Unexpected results in Chernozem soil respiration while measuring the effect of a bio-fertilizer on soil microbial activity.

PubMed

Bautista, Gabriela; Mátyás, Bence; Carpio, Isabel; Vilches, Richard; Pazmino, Karina

2017-01-01

The number of studies investigating the effect of bio-fertilizers is increasing because of their importance in sustainable agriculture and environmental quality. In our experiments, we measured the effect of different fertilizers on soil respiration. In the present study, we were looking for the cause of unexpected changes in CO2 values while examining Chernozem soil samples. We concluded that CO2 oxidizing microbes or methanotrophs may be present in the soil that periodically consume CO2 . This is unusual for a sample taken from the upper layer of well-ventilated Chernozem soil with optimal moisture content.

Unexpected results in Chernozem soil respiration while measuring the effect of a bio-fertilizer on soil microbial activity

PubMed Central

Bautista, Gabriela; Mátyás, Bence; Carpio, Isabel; Vilches, Richard; Pazmino, Karina

2017-01-01

The number of studies investigating the effect of bio-fertilizers is increasing because of their importance in sustainable agriculture and environmental quality. In our experiments, we measured the effect of different fertilizers on soil respiration. In the present study, we were looking for the cause of unexpected changes in CO2 values while examining Chernozem soil samples. We concluded that CO2 oxidizing microbes or methanotrophs may be present in the soil that periodically consume CO2 . This is unusual for a sample taken from the upper layer of well-ventilated Chernozem soil with optimal moisture content. PMID:29333243

[Interactions of straw, nitrogen fertilizer and bacterivorous nematodes on soil labile carbon and nitrogen and greenhouse gas emissions].

PubMed

Zhang, Teng-Hao; Wang, Nan; Liu, Man-Qiang; Li, Fang-Hui; Zhu, Kang-Li; Li, Hui-Xin; Hu, Feng

2014-11-01

A 3 x 2 factorial design of microcosm experiment was conducted to investigate the interactive effects of straw, nitrogen fertilizer and bacterivorous nematodes on soil microbial biomass carbon (C(mic)) and nitrogen (N(mic)), dissolved organic carbon (DOC) and nitrogen (DON), mineral nitrogen (NH(4+)-N and NO(3-)-N), and greenhouse gas (CO2, N2O and CH4) emissions. Results showed that straw amendment remarkably increased the numbers of bacterivorous nematodes and the contents of Cmic and Nmic, but Cmic and Nmic decreased with the increasing dose of nitrogen fertilization. The effects of bacterivorous nematodes strongly depended on either straw or nitrogen fertilization. The interactions of straw, nitrogen fertilization and bacterivorous nematodes on soil DOC, DON and mineral nitrogen were strong. Straw and nitrogen fertilization increased DOC and mineral nitrogen contents, but their influences on DON depended on the bacterivorous nematodes. The DOC and mineral nitrogen were negatively and positively influenced by the bacterivorous nematodes, re- spectively. Straw significantly promoted CO2 and N2O emissions but inhibited CH4 emission, while interactions between nematodes and nitrogen fertilization on emissions of greenhouse gases were obvious. In the presence of straw, nematodes increased cumulative CO2 emissions with low nitrogen fertilization, but decreased CO2 and N2O emissions with high nitrogen fertilization on the 56th day after incubation. In summary, mechanical understanding the soil ecological process would inevitably needs to consider the roles of soil microfauna.

Plant Regrowth as a Driver of Recent Enhancement of Terrestrial CO2 Uptake

NASA Astrophysics Data System (ADS)

Kondo, Masayuki; Ichii, Kazuhito; Patra, Prabir K.; Poulter, Benjamin; Calle, Leonardo; Koven, Charles; Pugh, Thomas A. M.; Kato, Etsushi; Harper, Anna; Zaehle, Sönke; Wiltshire, Andy

2018-05-01

The increasing strength of land CO2 uptake in the 2000s has been attributed to a stimulating effect of rising atmospheric CO2 on photosynthesis (CO2 fertilization). Using terrestrial biosphere models, we show that enhanced CO2 uptake is induced not only by CO2 fertilization but also an increasing uptake by plant regrowth (accounting for 0.33 ± 0.10 Pg C/year increase of CO2 uptake in the 2000s compared with the 1960s-1990s) with its effect most pronounced in eastern North America, southern-eastern Europe, and southeastern temperate Eurasia. Our analysis indicates that ecosystems in North America and Europe have established the current productive state through regrowth since the 1960s, and those in temperate Eurasia are still in a stage from regrowth following active afforestation in the 1980s-1990s. As the strength of model representation of CO2 fertilization is still in debate, plant regrowth might have a greater potential to sequester carbon than indicated by this study.

Iron in the Ross Sea: 2. Impact of discrete iron addition strategies

NASA Astrophysics Data System (ADS)

Arrigo, Kevin R.; Tagliabue, Alessandro

2005-03-01

Presented are results of a regional-scale numerical investigation into the effectiveness of Fe fertilization as a means to increase the efficiency of the biological pump in Fe-limited waters of the Ross Sea, Antarctica. This investigation was conducted using a modified version of the Coupled Ice And Ocean (CIAO) ecosystem model of the Ross Sea sector of the Southern Ocean. Four sets of experiments were performed, investigating the impacts of differences in (1) timing of fertilization, (2) duration of fertilization, (3) amount of Fe added, and (4) size of the fertilized patch. Results show that the stimulation of air-sea CO2 exchange (FCO2) depends primarily on the timing of fertilization, regardless of the amount of Fe added. When Fe was added at the optimal time of year, FCO2 from the atmosphere into the Ross Sea was increased by 3-22%, depending on fertilization strategy. Increasing patch size produced the largest response, and increasing initial Fe concentration produced the smallest. In all cases, as the intensity of Fe fertilization increased, the fertilization efficiency (increase in CO2 uptake per unit added Fe) dropped. Strategies that maximized the fertilization efficiency resulted in relatively little additional CO2 being drawn out of the atmosphere. To markedly increase oceanic uptake of atmospheric CO2 would require the addition of large amounts of Fe due to the low fertilization efficiencies associated with maximum air-sea CO2 exchange. Our results also show that differences in the fertilization strategy should be kept in mind when comparing the results of different Fe fertilization experiments.

CO2 and N-fertilization effects on fine-root length, production, and mortality: a 4-year ponderosa pine study.

PubMed

Phillips, Donald L; Johnson, Mark G; Tingey, David T; Storm, Marjorie J; Ball, J Timothy; Johnson, Dale W

2006-06-01

We conducted a 4-year study of juvenile Pinus ponderosa fine root (< or =2 mm) responses to atmospheric CO2 and N-fertilization. Seedlings were grown in open-top chambers at three CO2 levels (ambient, ambient+175 mumol/mol, ambient+350 mumol/mol) and three N-fertilization levels (0, 10, 20 g m(-2) year(-1)). Length and width of individual roots were measured from minirhizotron video images bimonthly over 4 years starting when the seedlings were 1.5 years old. Neither CO2 nor N-fertilization treatments affected the seasonal patterns of root production or mortality. Yearly values of fine-root length standing crop (m m(-2)), production (m m(-2) year(-1)), and mortality (m m(-2) year(-1)) were consistently higher in elevated CO2 treatments throughout the study, except for mortality in the first year; however, the only statistically significant CO2 effects were in the fine-root length standing crop (m m(-2)) in the second and third years, and production and mortality (m m(-2) year(-1)) in the third year. Higher mortality (m m(-2) year(-1)) in elevated CO2 was due to greater standing crop rather than shorter life span, as fine roots lived longer in elevated CO2. No significant N effects were noted for annual cumulative production, cumulative mortality, or mean standing crop. N availability did not significantly affect responses of fine-root standing crop, production, or mortality to elevated CO2. Multi-year studies at all life stages of trees are important to characterize belowground responses to factors such as atmospheric CO2 and N-fertilization. This study showed the potential for juvenile ponderosa pine to increase fine-root C pools and C fluxes through root mortality in response to elevated CO2.

Short-term effects of fertilization on photosynthesis and leaf morphology of field-grown loblolly pine following long-term exposure to elevated CO2 concentration

Treesearch

Chris A. Maier; Sari Palmroth; Eric Ward

2008-01-01

We examined effects of a first nitrogen (N) fertilizer application on upper-canopy needle morphology and gas exchange in ~20-m-tall loblolly pine (Pinus taeda L.) exposed to elevated carbon dioxide concentration ([CO2]) for 9 years. Duke Forest free-air CO2 enrichment (FACE) plots were split and half of...

INDEPENDENT AND CONTRASTING EFFECTS OF ELEVATED CO2 AND N-FERTILIZATION ROOT ARCHITECTURE

EPA Science Inventory

The effects of elevated CO2 and N fertilization on architecture of Pinus ponderosa fine roots and their associated mycorrhizal symbionts were measured over a 4-year period. The study was conducted in open-top field-exposure chambers located near Placerville, CA. A replicated (thr...

Tree ring evidence for limited direct CO2 fertilization of forests over the 20th century

NASA Astrophysics Data System (ADS)

Gedalof, Ze'ev; Berg, Aaron A.

2010-09-01

The effect that rising atmospheric CO2 levels will have on forest productivity and water use efficiency remains uncertain, yet it has critical implications for future rates of carbon sequestration and forest distributions. Efforts to understand the effect that rising CO2 will have on forests are largely based on growth chamber studies of seedlings, and the relatively small number of FACE sites. Inferences from these studies are limited by their generally short durations, artificial growing conditions, unnatural step-increases in CO2 concentrations, and poor replication. Here we analyze the global record of annual radial tree growth, derived from the International Tree ring Data Bank (ITRDB), for evidence of increasing growth rates that cannot be explained by climatic change alone, and for evidence of decreasing sensitivity to drought. We find that approximately 20 percent of sites globally exhibit increasing trends in growth that cannot be attributed to climatic causes, nitrogen deposition, elevation, or latitude, which we attribute to a direct CO2 fertilization effect. No differences were found between species in their likelihood to exhibit growth increases attributable to CO2 fertilization, although Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa), the two most commonly sampled species in the ITRDB, exhibit a CO2 fertilization signal at frequencies very near their upper and lower confidence limits respectively. Overall these results suggest that CO2 fertilization of forests will not counteract emissions or slow warming in any substantial fashion, but do suggest that future forest dynamics may differ from those seen today depending on site conditions and individual species' responses to elevated CO2.

DO ELEVATED CO2 AND N FERTILIZATION ALTER FINE ROOT-MYCORRHIZAE RELATIONSHIPS IN PINUS PONDEROSA?

EPA Science Inventory

Despite extensive studies on the response of plants to elevated CO2, climate change and N deposition, little is known about the response of roots and mycorrhizae in spite of their key role in plant water and nutrient acquisition. The effects of elevated CO2 and N fertilization on...

Root length, biomass, tissue chemistry and mycorrhizal colonization following 14 years of CO2 enrichment and 6 years of N fertilization in a warm temperate forest.

PubMed

Taylor, Benton N; Strand, Allan E; Cooper, Emily R; Beidler, Katilyn V; Schönholz, Marcos; Pritchard, Seth G

2014-09-01

Root systems serve important roles in carbon (C) storage and resource acquisition required for the increased photosynthesis expected in CO2-enriched atmospheres. For these reasons, understanding the changes in size, distribution and tissue chemistry of roots is central to predicting the ability of forests to capture anthropogenic CO2. We sampled 8000 cm(3) soil monoliths in a pine forest exposed to 14 years of free-air-CO2-enrichment and 6 years of nitrogen (N) fertilization to determine changes in root length, biomass, tissue C : N and mycorrhizal colonization. CO2 fumigation led to greater root length (98%) in unfertilized plots, but root biomass increases under elevated CO2 were only found for roots <1 mm in diameter in unfertilized plots (59%). Neither fine root [C] nor [N] was significantly affected by increased CO2. There was significantly less root biomass in N-fertilized plots (19%), but fine root [N] and [C] both increased under N fertilization (29 and 2%, respectively). Mycorrhizal root tip biomass responded positively to CO2 fumigation in unfertilized plots, but was unaffected by CO2 under N fertilization. Changes in fine root [N] and [C] call for further study of the effects of N fertilization on fine root function. Here, we show that the stimulation of pine roots by elevated CO2 persisted after 14 years of fumigation, and that trees did not rely exclusively on increased mycorrhizal associations to acquire greater amounts of required N in CO2-enriched plots. Stimulation of root systems by CO2 enrichment was seen primarily for fine root length rather than biomass. This observation indicates that studies measuring only biomass might overlook shifts in root systems that better reflect treatment effects on the potential for soil resource uptake. These results suggest an increase in fine root exploration as a primary means for acquiring additional soil resources under elevated CO2. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

EFFECTS OF ELEVATED CO-2 AND N FERTILIZATION ON FINE ROOT DYNAMICS AND FUNGAL GROWTH IN SEEDLING PINUS PONDEROSA

EPA Science Inventory

The effects of elevated CO-2 and N fertilization on fine root growth of Pinus ponderosa Dougl. ex P. Laws. C. Laws., grown in native soil in open-top field-exposure chambers at Placerville, CA, were monitored for a 2-year period using minirhizotrons. The experimental design was a...

Method of euthanasia influences the oocyte fertilization rate with fresh mouse sperm.

PubMed

Hazzard, Karen C; Watkins-Chow, Dawn E; Garrett, Lisa J

2014-11-01

In vitro fertilization (IVF) is used to produce mouse embryos for a variety of reasons. We evaluated the effect of the method of euthanasia on the fertilization rate in 2 different IVF protocols. Oocytes collected from C57BL/6J female mice euthanized by CO2 inhalation or cervical dislocation were used in IVF with fresh sperm from either wild-type or genetically engineered C57BL/6J. Compared with CO2 inhalation, cervical dislocation improved the resulting rate of fertilization by 18% in an IVF method using Cook media and by 13% in an IVF method using methyl-B cyclodextrin and reduced glutathione. The lower fertilization rate due to euthanasia by CO2 inhalation was accompanied by changes in blood pH and body temperature despite efforts to minimize temperature drops. In our hands, euthanasia by cervical dislocation improved fertilization rates and consequently reduced the number of egg-donor mice required.

A first-order analysis of the potential role of CO2 fertilization to affect the global carbon budget: A comparison of four terrestrial biosphere models

USGS Publications Warehouse

Kicklighter, D.W.; Bruno, M.; Donges, S.; Esser, G.; Heimann, Martin; Helfrich, J.; Ift, F.; Joos, F.; Kaduk, J.; Kohlmaier, G.H.; McGuire, A.D.; Melillo, J.M.; Meyer, R.; Moore, B.; Nadler, A.; Prentice, I.C.; Sauf, W.; Schloss, A.L.; Sitch, S.; Wittenberg, U.; Wurth, G.

1999-01-01

We compared the simulated responses of net primary production, heterotrophic respiration, net ecosystem production and carbon storage in natural terrestrial ecosystems to historical (1765 to 1990) and projected (1990 to 2300) changes of atmospheric CO2 concentration of four terrestrial biosphere models: the Bern model, the Frankfurt Biosphere Model (FBM), the High-Resolution Biosphere Model (HRBM) and the Terrestrial Ecosystem Model (TEM). The results of the model intercomparison suggest that CO2 fertilization of natural terrestrial vegetation has the potential to account for a large fraction of the so-called 'missing carbon sink' of 2.0 Pg C in 1990. Estimates of this potential are reduced when the models incorporate the concept that CO2 fertilization can be limited by nutrient availability. Although the model estimates differ on the potential size (126 to 461 Pg C) of the future terrestrial sink caused by CO2 fertilization, the results of the four models suggest that natural terrestrial ecosystems will have a limited capacity to act as a sink of atmospheric CO2 in the future as a result of physiological constraints and nutrient constraints on NPP. All the spatially explicit models estimate a carbon sink in both tropical and northern temperate regions, but the strength of these sinks varies over time. Differences in the simulated response of terrestrial ecosystems to CO2 fertilization among the models in this intercomparison study reflect the fact that the models have highlighted different aspects of the effect of CO2 fertilization on carbon dynamics of natural terrestrial ecosystems including feedback mechanisms. As interactions with nitrogen fertilization, climate change and forest regrowth may play an important role in simulating the response of terrestrial ecosystems to CO2 fertilization, these factors should be included in future analyses. Improvements in spatially explicit data sets, whole-ecosystems experiments and the availability of net carbon exchange measurements across the globe will also help to improve future evaluations of the role of CO2 fertilization on terrestrial carbon storage.

Projected land photosynthesis constrained by changes in the seasonal cycle of atmospheric CO2.

PubMed

Wenzel, Sabrina; Cox, Peter M; Eyring, Veronika; Friedlingstein, Pierre

2016-10-27

Uncertainties in the response of vegetation to rising atmospheric CO 2 concentrations contribute to the large spread in projections of future climate change. Climate-carbon cycle models generally agree that elevated atmospheric CO 2 concentrations will enhance terrestrial gross primary productivity (GPP). However, the magnitude of this CO 2 fertilization effect varies from a 20 per cent to a 60 per cent increase in GPP for a doubling of atmospheric CO 2 concentrations in model studies. Here we demonstrate emergent constraints on large-scale CO 2 fertilization using observed changes in the amplitude of the atmospheric CO 2 seasonal cycle that are thought to be the result of increasing terrestrial GPP. Our comparison of atmospheric CO 2 measurements from Point Barrow in Alaska and Cape Kumukahi in Hawaii with historical simulations of the latest climate-carbon cycle models demonstrates that the increase in the amplitude of the CO 2 seasonal cycle at both measurement sites is consistent with increasing annual mean GPP, driven in part by climate warming, but with differences in CO 2 fertilization controlling the spread among the model trends. As a result, the relationship between the amplitude of the CO 2 seasonal cycle and the magnitude of CO 2 fertilization of GPP is almost linear across the entire ensemble of models. When combined with the observed trends in the seasonal CO 2 amplitude, these relationships lead to consistent emergent constraints on the CO 2 fertilization of GPP. Overall, we estimate a GPP increase of 37 ± 9 per cent for high-latitude ecosystems and 32 ± 9 per cent for extratropical ecosystems under a doubling of atmospheric CO 2 concentrations on the basis of the Point Barrow and Cape Kumukahi records, respectively.

Ocean acidification compromises recruitment success of the threatened Caribbean coral Acropora palmata

PubMed Central

Albright, Rebecca; Mason, Benjamin; Miller, Margaret; Langdon, Chris

2010-01-01

Ocean acidification (OA) refers to the ongoing decline in oceanic pH resulting from the uptake of atmospheric CO2. Mounting experimental evidence suggests that OA will have negative consequences for a variety of marine organisms. Whereas the effect of OA on the calcification of adult reef corals is increasingly well documented, effects on early life history stages are largely unknown. Coral recruitment, which necessitates successful fertilization, larval settlement, and postsettlement growth and survivorship, is critical to the persistence and resilience of coral reefs. To determine whether OA threatens successful sexual recruitment of reef-building corals, we tested fertilization, settlement, and postsettlement growth of Acropora palmata at pCO2 levels that represent average ambient conditions during coral spawning (∼400 μatm) and the range of pCO2 increases that are expected to occur in this century [∼560 μatm (mid-CO2) and ∼800 μatm (high-CO2)]. Fertilization, settlement, and growth were all negatively impacted by increasing pCO2, and impairment of fertilization was exacerbated at lower sperm concentrations. The cumulative impact of OA on fertilization and settlement success is an estimated 52% and 73% reduction in the number of larval settlers on the reef under pCO2 conditions projected for the middle and the end of this century, respectively. Additional declines of 39% (mid-CO2) and 50% (high-CO2) were observed in postsettlement linear extension rates relative to controls. These results suggest that OA has the potential to impact multiple, sequential early life history stages, thereby severely compromising sexual recruitment and the ability of coral reefs to recover from disturbance. PMID:21059900

Ocean acidification compromises recruitment success of the threatened Caribbean coral Acropora palmata.

PubMed

Albright, Rebecca; Mason, Benjamin; Miller, Margaret; Langdon, Chris

2010-11-23

Ocean acidification (OA) refers to the ongoing decline in oceanic pH resulting from the uptake of atmospheric CO(2). Mounting experimental evidence suggests that OA will have negative consequences for a variety of marine organisms. Whereas the effect of OA on the calcification of adult reef corals is increasingly well documented, effects on early life history stages are largely unknown. Coral recruitment, which necessitates successful fertilization, larval settlement, and postsettlement growth and survivorship, is critical to the persistence and resilience of coral reefs. To determine whether OA threatens successful sexual recruitment of reef-building corals, we tested fertilization, settlement, and postsettlement growth of Acropora palmata at pCO(2) levels that represent average ambient conditions during coral spawning (∼400 μatm) and the range of pCO(2) increases that are expected to occur in this century [∼560 μatm (mid-CO(2)) and ∼800 μatm (high-CO(2))]. Fertilization, settlement, and growth were all negatively impacted by increasing pCO(2), and impairment of fertilization was exacerbated at lower sperm concentrations. The cumulative impact of OA on fertilization and settlement success is an estimated 52% and 73% reduction in the number of larval settlers on the reef under pCO(2) conditions projected for the middle and the end of this century, respectively. Additional declines of 39% (mid-CO(2)) and 50% (high-CO(2)) were observed in postsettlement linear extension rates relative to controls. These results suggest that OA has the potential to impact multiple, sequential early life history stages, thereby severely compromising sexual recruitment and the ability of coral reefs to recover from disturbance.

Ocean acidification and fertilization in the antarctic sea urchin Sterechinus neumayeri: the importance of polyspermy.

PubMed

Sewell, Mary A; Millar, Russell B; Yu, Pauline C; Kapsenberg, Lydia; Hofmann, Gretchen E

2014-01-01

Ocean acidification (OA), the reduction of the seawater pH as a result of increasing levels of atmospheric CO2, is an important climate change stressor in the Southern Ocean and Antarctic. We examined the impact of OA on fertilization success in the Antarctic sea urchin Sterechinus neumayeri using pH treatment conditions reflective of the current and near-future "pH seascape" for this species: current (control: pH 8.052, 384.1 μatm of pCO2), a high CO2 treatment approximating the 0.2-0.3 unit decrease in pH predicted for 2100 (high CO2: pH 7.830, 666.0 μatm of pCO2), and an intermediate medium CO2 (pH 7.967, 473.4 μatm of pCO2). Using a fertilization kinetics approach and mixed-effect models, we observed significant variation in the OA response between individual male/female pairs (N = 7) and a significant population-level increase (70-100%) in tb (time for a complete block to polyspermy) at medium and high CO2, a mechanism that potentially explains the higher levels of abnormal development seen in OA conditions. However, two pairs showed higher fertilization success with CO2 treatment and a nonsignificant effect. Future studies should focus on the mechanisms and levels of interindividual variability in OA response, so that we can consider the potential for selection and adaptation of organisms to a future ocean.

Drivers of multi-century trends in the atmospheric CO2 mean annual cycle in a prognostic ESM

NASA Astrophysics Data System (ADS)

Liptak, Jessica; Keppel-Aleks, Gretchen; Lindsay, Keith

2017-03-01

The amplitude of the mean annual cycle of atmospheric CO2 is a diagnostic of seasonal surface-atmosphere carbon exchange. Atmospheric observations show that this quantity has increased over most of the Northern Hemisphere (NH) extratropics during the last 3 decades, likely from a combination of enhanced atmospheric CO2, climate change, and anthropogenic land use change. Accurate climate prediction requires accounting for long-term interactions between the environment and carbon cycling; thus, analysis of the evolution of the mean annual cycle in a fully prognostic Earth system model may provide insight into the multi-decadal influence of environmental change on the carbon cycle. We analyzed the evolution of the mean annual cycle in atmospheric CO2 simulated by the Community Earth System Model (CESM) from 1950 to 2300 under three scenarios designed to separate the effects of climate change, atmospheric CO2 fertilization, and land use change. The NH CO2 seasonal amplitude increase in the CESM mainly reflected enhanced primary productivity during the growing season due to climate change and the combined effects of CO2 fertilization and nitrogen deposition over the mid- and high latitudes. However, the simulations revealed shifts in key climate drivers of the atmospheric CO2 seasonality that were not apparent before 2100. CO2 fertilization and nitrogen deposition in boreal and temperate ecosystems were the largest contributors to mean annual cycle amplification over the midlatitudes for the duration of the simulation (1950-2300). Climate change from boreal ecosystems was the main driver of Arctic CO2 annual cycle amplification between 1950 and 2100, but CO2 fertilization had a stronger effect on the Arctic CO2 annual cycle amplitude during 2100-2300. Prior to 2100, the NH CO2 annual cycle amplitude increased in conjunction with an increase in the NH land carbon sink. However, these trends decoupled after 2100, underscoring that an increasing atmospheric CO2 annual cycle amplitude does not necessarily imply a strengthened terrestrial carbon sink.

Fertilizer application timing influences greenhouse gas fluxes over a growing season.

PubMed

Phillips, Rebecca L; Tanaka, Donald L; Archer, David W; Hanson, Jon D

2009-01-01

Microbial production and consumption of greenhouse gases (GHG) is influenced by temperature and nutrients, especially during the first few weeks after agricultural fertilization. The effect of fertilization on GHG fluxes should occur during and shortly after application, yet data indicating how application timing affects both GHG fluxes and crop yields during a growing season are lacking. We designed a replicated (n = 5) field experiment to test for the short-term effect of fertilizer application timing on fluxes of methane (CH(4)), carbon dioxide (CO(2)), and nitrous oxide (N(2)O) over a growing season in the northern Great Plains. Each 0.30-ha plot was planted to maize (Zea mays L.) and treated similarly with the exception of fertilizer timing: five plots were fertilized with urea in early spring (1 April) and five plots were fertilized with urea in late spring (13 May). We hypothesized time-integrated fluxes over a growing season would be greater for the late-spring treatment, resulting in a greater net GHG flux, as compared to the early-spring treatment. Data collected on 59 dates and integrated over a 5-mo time course indicated CO(2) fluxes were greater (P < 0.0001) and CH(4) fluxes were lower (P < 0.05) for soils fertilized in late spring. Net GHG flux was also significantly affected by treatment, with 0.84 +/- 0.11 kg CO(2) equivalents m(-2) for early spring and 1.04 +/- 0.13 kg CO(2) equivalents m(-2) for late spring. Nitrous oxide fluxes, however, were similar for both treatments. Results indicate fertilizer application timing influences net GHG emissions in dryland cropping systems.

Effect of atmospheric carbon dioxide levels and nitrate fertilization on glucosinolate biosynthesis in mechanically damaged Arabidopsis plants.

PubMed

Paudel, Jamuna Risal; Amirizian, Alexandre; Krosse, Sebastian; Giddings, Jessica; Ismail, Shoieb Akaram Arief; Xia, Jianguo; Gloer, James B; van Dam, Nicole M; Bede, Jacqueline C

2016-03-22

Increased atmospheric carbon dioxide (CO2) levels predicted to occur before the end of the century will impact plant metabolism. In addition, nitrate availability will affect metabolism and levels of nitrogen-containing defense compounds, such as glucosinolates (GSLs). We compared Arabidopsis foliar metabolic profile in plants grown under two CO2 regimes (440 vs 880 ppm), nitrate fertilization (1 mM vs 10 mM) and in response to mechanical damage of rosette leaves. Constitutive foliar metabolites in nitrate-limited plants show distinct global patterns depending on atmospheric CO2 levels; in contrast, plants grown under higher nitrate fertilization under elevated atmospheric CO2 conditions have a unique metabolite signature. Nitrate fertilization dampens the jasmonate burst in response to wounding in plants grown at elevated CO2 levels. Leaf GSL profile mirrors the jasmonate burst; in particular, indole GSLs increase in response to damage in plants grown at ambient CO2 but only in nitrate-limited plants grown under elevated CO2 conditions. This may reflect a reduced capacity of C3 plants grown under enriched CO2 and nitrate levels to signal changes in oxidative stress and has implications for future agricultural management practices.

Fertilization success of an arctic sea urchin species, Strongylocentrotus droebachiensis (O. F. Müller, 1776) under CO2-induced ocean acidification

NASA Astrophysics Data System (ADS)

Bögner, D.; Bickmeyer, U.; Köhler, A.

2013-05-01

Sea urchins as broadcasting spawners, release their gametes into open water for fertilization, thus being particularly vulnerable to ocean acidification. In this study, we assessed the effects of different pH scenarios on fertilization success of Strongylocentrotus droebachiensis, collected at Spitsbergen, Arctic. We achieved acidification by bubbling CO2 into filtered seawater using partial pressures (pCO2) of 180, 380, 980, 1400 and 3000 μatm}. Untreated filtered seawater was used as control. We recorded fertilization rates and diagnosed morphological aberrations after post-fertilization periods of 1 h and 3 h under different exposure conditions in experiments with and without pre-incubation of the eggs prior to fertilization. In parallel, we conducted measurements of intracellular pH changes using BCECF/AM in unfertilized eggs exposed to a range of acidified seawater. We observed increasing rates of polyspermy in relation to higher seawater pCO2, which might be due to failures in the formation of the fertilization envelope. In addition, our experiments showed anomalies in fertilized eggs: incomplete lifting-off of the fertilization envelope and blebs of the hyaline layer. Other drastic malformations consisted of constriction, extrusion, vacuolization or degeneration (observed as a gradient from the cortex to the central region of the cell) of the egg cytoplasm, and irregular cell divisions until 2- to 4-cell stages. The intracellular pH (pHi) decreased significantly from 1400 μatm on. All results indicate a decreasing fertilization success at CO2 concentrations from 1400 μatm upwards. Exposure time to low pH might be a threatening factor for the cellular buffer capacity, viability, and development after fertilization.

Shifting terrestrial feedbacks from CO2 fertilization to global warming

NASA Astrophysics Data System (ADS)

Peñuelas, Josep; Ciais, Philippe; Janssens, Ivan; Canadell, Josep; Obersteiner, Michael; Piao, Shilong; Vautard, Robert; Sardans Jordi Sardans, Jordi

2016-04-01

Humans are increasingly fertilizing the planet. Our activities are increasing atmospheric concentrations of carbon dioxide, nitrogen inputs to ecosystems and global temperatures. Individually and combined, they lead to biospheric availability of carbon and nitrogen, enhanced metabolic activity, and longer growing seasons. Plants can consequently grow more and take up more carbon that can be stored in ecosystem carbon pools, thus enhancing carbon sinks for atmospheric CO2. Data on the increased strength of carbon sinks are, however, inconclusive: Some data (eddy covariance, short-term experiments on elevated CO2 and nutrient fertilization) suggest that biospheric carbon uptake is already effectively increasing but some other data suggest it is not, or are not general and conclusive (tree-ring, forest inventory). The combined land-ocean CO2 sink flux per unit of excess atmospheric CO2 above preindustrial levels declined over 1959-2012 by a factor of about 1/3, implying that CO2 sinks increased more slowly than excess CO2. We will discuss the available data, and the discussion will drive us to revisit our projections for enhanced carbon sinks. We will reconsider the performance of the modulators of increased carbon uptake in a CO2 fertilized and warmed world: nutrients, climate, land use and pollution. Nutrient availability in particular plays a crucial role. A simple mass-balance approach indicates that limited phosphorus availability and the corresponding N:P imbalances can jointly reduce the projected future carbon storage by natural ecosystems during this century. We then present a new paradigm: we are shifting from a fertilization to a warming era. Compared to the historical period, future impacts of warming will be larger than the benefits of CO2 fertilization given nutrient limitations, management and disturbance (which reduces C stocks and thus sequestration potential) and because CO2 will decrease by 2050 in RCP2.6, meaning loss of CO2 fertilization, and CO2 stabilizes by 2060 in RCP4.5. So in light of the Paris agreement, it is more important to investigate climate change impacts on carbon stocks than to expect a continuation of increasing sink due to CO2 fertilization, which will have only a small role or disappear in RCP2.6 during this century.

Soil CO2 Efflux and Its Components Responded Differently to Throughfall Exclusion and Fertilization in a Loblolly Pine (Pinus taeda) Plantation

NASA Astrophysics Data System (ADS)

Yang, J.; Luedtke, C.; Akers, K.; McGuire, M.; Aubrey, D. P.; Teskey, R. O.

2014-12-01

Soil CO2 efflux (RS) is an important component of forest ecosystem carbon budgets and net ecosystem CO2 exchange, but little is known about how RS and its components respond to decreasing soil moisture and changes in soil fertility. The experiment design was a 2 X 2 factorial combination of fertilization (2 levels) and precipitation (throughfall exclusion, 2 levels) replicated in four blocks. We measured RS along with soil temperature (Ts) and soil moisture (WS) from 2012 to 2014 in a loblolly pine plantation in Washington, GA. The autotrophic (RA) and heterotrophic (RH) components of soil CO2 efflux were separated using trenched plots. Our objectives were to (1) quantify impacts of throughfall exclusion and fertilization on RS and its components (RA, RH).and (2) determine soil CO2efflux and its components individually response to environmental factors and biological factors in throughfall exclusion and fertilization treatments. Annual mean RS was 2.11, 1.73, 2.09 and 1.92 for treatments of control, fertilization, throughfall exclusion and combination of fertilization and throughfall exclusion, respectively, from 2012 to 2013. The apparent Q10 for RS was 2.26, 2.25, 2.12 and 2.35 in the four treatments, respectively. There were no significant differences in RS among treatments except between the Ws treatments. However, there was slight reduction in RS and RA in fertilization and the fertilization plus throughfall exclusion treatment. In all treaments, Ts explained more than 80% of variation in RS. The contribution of CO2-derived from ectomycorrhizal hyphae was less than 15%. RS and RH was better predicted by TS in the dormant season than the growing season, indicating that additional factors such as root growth and photosynthesis became more important contributors to RS during the growing season. Fertilization slightly decreased RS mainly from a decrease in RH. Throughfall exclusion increased the contribution of RA to RS. We concluded that soil moisture had more effect on RS and its components than changes in fertility.

Nitrogen fertilization raises CO2 efflux from inorganic carbon: A global assessment.

PubMed

Zamanian, Kazem; Zarebanadkouki, Mohsen; Kuzyakov, Yakov

2018-07-01

Nitrogen (N) fertilization is an indispensable agricultural practice worldwide, serving the survival of half of the global population. Nitrogen transformation (e.g., nitrification) in soil as well as plant N uptake releases protons and increases soil acidification. Neutralizing this acidity in carbonate-containing soils (7.49 × 10 9  ha; ca. 54% of the global land surface area) leads to a CO 2 release corresponding to 0.21 kg C per kg of applied N. We here for the first time raise this problem of acidification of carbonate-containing soils and assess the global CO 2 release from pedogenic and geogenic carbonates in the upper 1 m soil depth. Based on a global N-fertilization map and the distribution of soils containing CaCO 3 , we calculated the CO 2 amount released annually from the acidification of such soils to be 7.48 × 10 12  g C/year. This level of continuous CO 2 release will remain constant at least until soils are fertilized by N. Moreover, we estimated that about 273 × 10 12  g CO 2 -C are released annually in the same process of CaCO 3 neutralization but involving liming of acid soils. These two CO 2 sources correspond to 3% of global CO 2 emissions by fossil fuel combustion or 30% of CO 2 by land-use changes. Importantly, the duration of CO 2 release after land-use changes usually lasts only 1-3 decades before a new C equilibrium is reached in soil. In contrast, the CO 2 released by CaCO 3 acidification cannot reach equilibrium, as long as N fertilizer is applied until it becomes completely neutralized. As the CaCO 3 amounts in soils, if present, are nearly unlimited, their complete dissolution and CO 2 release will take centuries or even millennia. This emphasizes the necessity of preventing soil acidification in N-fertilized soils as an effective strategy to inhibit millennia of CO 2 efflux to the atmosphere. Hence, N fertilization should be strictly calculated based on plant-demand, and overfertilization should be avoided not only because N is a source of local and regional eutrophication, but also because of the continuous CO 2 release by global acidification. © 2018 John Wiley & Sons Ltd.

Reducing Soil CO2 Emission and Improving Upland Rice Yield with no-Tillage, Straw Mulch and Nitrogen Fertilization in Northern Benin

NASA Astrophysics Data System (ADS)

Dossou-Yovo, E.; Brueggemann, N.; Naab, J.; Huat, J.; Ampofo, E.; Ago, E.; Agbossou, E.

2015-12-01

To explore effective ways to decrease soil CO2 emission and increase grain yield, field experiments were conducted on two upland rice soils (Lixisols and Gleyic Luvisols) in northern Benin in West Africa. The treatments were two tillage systems (no-tillage, and manual tillage), two rice straw managements (no rice straw, and rice straw mulch at 3 Mg ha-1) and three nitrogen fertilizers levels (no nitrogen, recommended level of nitrogen: 60 kg ha-1, and high level of nitrogen: 120 kg ha-1). Potassium and phosphorus fertilizers were applied to be non-limiting at 40 kg K2O ha-1 and 40 kg P2O5 ha-1. Four replications of the twelve treatment combinations were arranged in a randomized complete block design. Soil CO2 emission, soil moisture and soil temperature were measured at 5 cm depth in 6 to 10 days intervals during the rainy season and every two weeks during the dry season. Soil moisture was the main factor explaining the seasonal variability of soil CO2 emission. Much larger soil CO2 emissions were found in rainy than dry season. No-tillage planting significantly reduced soil CO2 emissions compared with manual tillage. Higher soil CO2 emissions were recorded in the mulched treatments. Soil CO2 emissions were higher in fertilized treatments compared with non fertilized treatments. Rice biomass and yield were not significantly different as a function of tillage systems. On the contrary, rice biomass and yield significantly increased with application of rice straw mulch and nitrogen fertilizer. The highest response of rice yield to nitrogen fertilizer addition was obtained for 60 kg N ha-1 in combination with 3 Mg ha-1 of rice straw for the two tillage systems. Soil CO2 emission per unit grain yield was lower under no-tillage, rice straw mulch and nitrogen fertilizer treatments. No-tillage combined with rice straw mulch and 60 kg N ha-1 could be used by smallholder farmers to achieve higher grain yield and lower soil CO2 emission in upland rice fields in northern Benin.

Carbon dioxide emissions from semi-arid soils amended with biochar alone or combined with mineral and organic fertilizers.

PubMed

Fernández, José M; Nieto, M Aurora; López-de-Sá, Esther G; Gascó, Gabriel; Méndez, Ana; Plaza, César

2014-06-01

Semi-arid soils cover a significant area of Earth's land surface and typically contain large amounts of inorganic C. Determining the effects of biochar additions on CO2 emissions from semi-arid soils is therefore essential for evaluating the potential of biochar as a climate change mitigation strategy. Here, we measured the CO2 that evolved from semi-arid calcareous soils amended with biochar at rates of 0 and 20tha(-1) in a full factorial combination with three different fertilizers (mineral fertilizer, municipal solid waste compost, and sewage sludge) applied at four rates (equivalent to 0, 75, 150, and 225kg potentially available Nha(-1)) during 182 days of aerobic incubation. A double exponential model, which describes cumulative CO2 emissions from two active soil C compartments with different turnover rates (one relatively stable and the other more labile), was found to fit very well all the experimental datasets. In general, the organic fertilizers increased the size and decomposition rate of the stable and labile soil C pools. In contrast, biochar addition had no effects on any of the double exponential model parameters and did not interact with the effects ascribed to the type and rate of fertilizer. After 182 days of incubation, soil organic and microbial biomass C contents tended to increase with increasing the application rates of organic fertilizer, especially of compost, whereas increasing the rate of mineral fertilizer tended to suppress microbial biomass. Biochar was found to increase both organic and inorganic C contents in soil and not to interact with the effects of type and rate of fertilizer on C fractions. As a whole, our results suggest that the use of biochar as enhancer of semi-arid soils, either alone or combined with mineral and organic fertilizers, is unlikely to increase abiotic and biotic soil CO2 emissions. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of ultrashort gamete co-incubation time on porcine in vitro fertilization.

PubMed

Almiñana, C; Gil, M A; Cuello, C; Parrilla, I; Roca, J; Vazquez, J M; Martinez, E A

2008-07-01

A reduction in co-incubation time has been suggested as an alternative method to reduce polyspermic fertilization. The aim of this study was to evaluate the effect of short periods of gamete co-incubation during pig in vitro fertilization. A total of 2,833 in vitro matured oocytes were inseminated with thawed spermatozoa and coincubated for 0.25, 1, 2, 3, 7, 10 min and 6h. The oocytes from the 0.25-10 min groups were washed three times in modified Tris-buffered medium (mTBM) medium to remove spermatozoa not bound to the zona and transferred to the same medium (containing no spermatozoa) until 6h of co-incubation time were completed. After 6h, presumptive zygotes from each group were cultured in NCSU-23 medium for 12-15 h to assess fertilization parameters. After each period of co-incubation, 45-50 oocytes from each group were stained with Hoechst-33342 and the number of spermatozoa bound to the zona was counted. Although the number of zona bound spermatozoa increased (p<0.05) with the co-incubation time, no increase was observed in penetration rates among groups from 2 min to 6h of co-incubation time (ranging from 53.5+/-2.8 to 61.3+/-2.6%). Similarly, the efficiency of fertilization reached a maximum for the 2 min of co-incubation group with values ranging between 32.3+/-2.4 and 41.9+/-2.5%. The reduction of co-incubation time did not affect the monospermy rate (range: 71.3+/-3.4-80.2+/-3.8%) and the mean number of spermatozoa/oocyte (range: 1.2+/-0.4-1.4+/-0.5). These results show that, under our in vitro conditions, high penetration rate can be obtained with co-incubation times as short as 2 min, although monospermy could not be improved using this strategy.

Field-quantified responses of tropical rainforest aboveground productivity to increasing CO2 and climatic stress, 1997-2009

NASA Astrophysics Data System (ADS)

Clark, Deborah A.; Clark, David B.; Oberbauer, Steven F.

2013-06-01

A directional change in tropical-forest productivity, a large component in the global carbon budget, would affect the rate of increase in atmospheric carbon dioxide ([CO2]). One current hypothesis is that "CO2 fertilization" has been increasing tropical forest productivity. Some lines of evidence instead suggest climate-driven productivity declines. Relevant direct field observations remain extremely limited for this biome. Using a unique long-term record of annual field measurements, we assessed annual aboveground net primary productivity (ANPP) and its relation to climatic factors and [CO2] in a neotropical rainforest through 1997-2009. Over this 12 year period, annual productivity did not increase, as would be expected with a dominant CO2 fertilization effect. Instead, the negative responses of ANPP components to climatic stress far exceeded the small positive responses associated with increasing [CO2]. Annual aboveground biomass production was well explained (73%) by the independent negative effects of increasing minimum temperatures and greater dry-season water stress. The long-term records enable a first field-based estimate of the [CO2] response of tropical forest ANPP: 5.24 g m-2 yr-1 yr-1 (the summed [CO2]-associated increases in two of the four production components; the largest component, leaf litterfall, showed no [CO2] association). If confirmed by longer data series, such a small response from a fertile tropical rainforest would indicate that current global models overestimate the benefits from CO2 fertilization for this biome, where most forests' poorer nutrient status more strongly constrains productivity responses to increasing [CO2]. Given the rapidly intensifying warming across tropical regions, tropical forest productivity could sharply decline through coming decades.

Method of Euthanasia Influences the Oocyte Fertilization Rate with Fresh Mouse Sperm

PubMed Central

Hazzard, Karen C; Watkins-Chow, Dawn E; Garrett, Lisa J

2014-01-01

In vitro fertilization (IVF) is used to produce mouse embryos for a variety of reasons. We evaluated the effect of the method of euthanasia on the fertilization rate in 2 different IVF protocols. Oocytes collected from C57BL/6J female mice euthanized by CO2 inhalation or cervical dislocation were used in IVF with fresh sperm from either wild-type or genetically engineered C57BL/6J. Compared with CO2 inhalation, cervical dislocation improved the resulting rate of fertilization by 18% in an IVF method using Cook media and by 13% in an IVF method using methyl-B cyclodextrin and reduced glutathione. The lower fertilization rate due to euthanasia by CO2 inhalation was accompanied by changes in blood pH and body temperature despite efforts to minimize temperature drops. In our hands, euthanasia by cervical dislocation improved fertilization rates and consequently reduced the number of egg-donor mice required. PMID:25650969

Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees.

PubMed

Silva, Lucas C R; Salamanca-Jimenez, Alveiro; Doane, Timothy A; Horwath, William R

2015-08-21

The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases ((13)CO2 and (15)NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the (13)CO2 pulse, assimilation and transport of the (15)NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history.

Organic and inorganic fertilizer effect on soil CO2 flux, microbial biomass, and growth of Nigella sativa L.

NASA Astrophysics Data System (ADS)

Salehi, Aliyeh; Fallah, Seyfollah; Sourki, Ali Abasi

2017-01-01

Cattle manure has a high carbon/nitrogen ratio and may not decompose; therefore, full-dose application of urea fertilizer might improve biological properties by increasing manure decomposition. This study aimed to investigate the effect of combining cattle manure and urea fertilizer on soil CO2 flux, microbial biomass carbon, and dry matter accumulation during Nigella sativa L. (black cumin) growth under field conditions. The treatments were control, cattle manure, urea, different levels of split and full-dose integrated fertilizer. The results showed that integrated application of cattle manure and chemical fertilizer significantly increased microbial biomass carbon by 10%, soil organic carbon by 2.45%, total N by 3.27%, mineral N at the flowering stage by 7.57%, and CO2 flux by 9% over solitary urea application. Integrated application increased microbial biomass carbon by 10% over the solitary application and the full-dose application by 5% over the split application. The soil properties and growth parameters of N. sativa L. benefited more from the full-dose application than the split application of urea. Cattle manure combined with chemical fertilizer and the full-dose application of urea increased fertilizer efficiency and improved biological soil parameters and plant growth. This method decreased the cost of top dressing urea fertilizer and proved beneficial for the environment and medicinal plant health.

Tillage, Mulch and N Fertilizer Affect Emissions of CO2 under the Rain Fed Condition

PubMed Central

Tanveer, Sikander Khan; Wen, Xiaoxia; Lu, Xing Li; Zhang, Junli; Liao, Yuncheng

2013-01-01

A two year (2010–2012) study was conducted to assess the effects of different agronomic management practices on the emissions of CO2 from a field of non-irrigated wheat planted on China's Loess Plateau. Management practices included four tillage methods i.e. T1: (chisel plow tillage), T2: (zero-tillage), T3: (rotary tillage) and T4: (mold board plow tillage), 2 mulch levels i.e., M0 (no corn residue mulch) and M1 (application of corn residue mulch) and 5 levels of N fertilizer (0, 80, 160, 240, 320 kg N/ha). A factorial experiment having a strip split-split arrangement, with tillage methods in the main plots, mulch levels in the sub plots and N-fertilizer levels in the sub-sub plots with three replicates, was used for this study. The CO2 data were recorded three times per week using a portable GXH-3010E1 gas analyzer. The highest CO2 emissions were recorded following rotary tillage, compared to the lowest emissions from the zero tillage planting method. The lowest emissions were recorded at the 160 kg N/ha, fertilizer level. Higher CO2 emissions were recorded during the cropping year 2010–11 relative to the year 2011–12. During cropping year 2010–11, applications of corn residue mulch significantly increased CO2 emissions in comparison to the non-mulched treatments, and during the year 2011–12, equal emissions were recorded for both types of mulch treatments. Higher CO2 emissions were recorded immediately after the tillage operations. Different environmental factors, i.e., rain, air temperatures, soil temperatures and soil moistures, had significant effects on the CO2 emissions. We conclude that conservation tillage practices, i.e., zero tillage, the use of corn residue mulch and optimum N fertilizer use, can reduce CO2 emissions, give better yields and provide environmentally friendly options. PMID:24086256

Projected near-future levels of temperature and pCO2 reduce coral fertilization success.

PubMed

Albright, Rebecca; Mason, Benjamin

2013-01-01

Increases in atmospheric carbon dioxide (pCO2) are projected to contribute to a 1.1-6.4°C rise in global average surface temperatures and a 0.14-0.35 reduction in the average pH of the global surface ocean by 2100. If realized, these changes are expected to have negative consequences for reef-building corals including increased frequency and severity of coral bleaching and reduced rates of calcification and reef accretion. Much less is known regarding the independent and combined effects of temperature and pCO2 on critical early life history processes such as fertilization. Here we show that increases in temperature (+3°C) and pCO2 (+400 µatm) projected for this century negatively impact fertilization success of a common Indo-Pacific coral species, Acropora tenuis. While maximum fertilization did not differ among treatments, the sperm concentration required to obtain 50% of maximum fertilization increased 6- to 8- fold with the addition of a single factor (temperature or CO2) and nearly 50- fold when both factors interact. Our results indicate that near-future changes in temperature and pCO2 narrow the range of sperm concentrations that are capable of yielding high fertilization success in A. tenuis. Increased sperm limitation, in conjunction with adult population decline, may have severe consequences for coral reproductive success. Impaired sexual reproduction will further challenge corals by inhibiting population recovery and adaptation potential.

Projected Near-Future Levels of Temperature and pCO2 Reduce Coral Fertilization Success

PubMed Central

Albright, Rebecca; Mason, Benjamin

2013-01-01

Increases in atmospheric carbon dioxide (pCO2) are projected to contribute to a 1.1–6.4°C rise in global average surface temperatures and a 0.14–0.35 reduction in the average pH of the global surface ocean by 2100. If realized, these changes are expected to have negative consequences for reef-building corals including increased frequency and severity of coral bleaching and reduced rates of calcification and reef accretion. Much less is known regarding the independent and combined effects of temperature and pCO2 on critical early life history processes such as fertilization. Here we show that increases in temperature (+3°C) and pCO2 (+400 µatm) projected for this century negatively impact fertilization success of a common Indo-Pacific coral species, Acropora tenuis. While maximum fertilization did not differ among treatments, the sperm concentration required to obtain 50% of maximum fertilization increased 6- to 8- fold with the addition of a single factor (temperature or CO2) and nearly 50- fold when both factors interact. Our results indicate that near-future changes in temperature and pCO2 narrow the range of sperm concentrations that are capable of yielding high fertilization success in A. tenuis. Increased sperm limitation, in conjunction with adult population decline, may have severe consequences for coral reproductive success. Impaired sexual reproduction will further challenge corals by inhibiting population recovery and adaptation potential. PMID:23457572

Direct effects of increasing carbon dioxide on vegetation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strain, B R; Cure, J D

1985-12-01

CO/sub 2/ is an essential environmental resource. It is required as a raw material of the orderly development of all green plants. As the availability of CO/sub 2/ increases, perhaps reaching two or three times the concentration prevailing in preindustrial times, plants and all other organisms dependent on them for food will be affected. Humans are releasing a gaseous fertilizer into the global atmosphere in quantities sufficient to affect all life. This volume considers the direct effects of global CO/sub 2/ fertilization on plants and thus on all other life. Separate abstracts have been prepared for individual papers. (ACR)

Reduced CO2 fertilization effect in temperate C3 grasslands under more extreme weather conditions

NASA Astrophysics Data System (ADS)

Obermeier, W. A.; Lehnert, L. W.; Kammann, C. I.; Müller, C.; Grünhage, L.; Luterbacher, J.; Erbs, M.; Moser, G.; Seibert, R.; Yuan, N.; Bendix, J.

2017-02-01

The increase in atmospheric greenhouse gas concentrations from anthropogenic activities is the major driver of recent global climate change. The stimulation of plant photosynthesis due to rising atmospheric carbon dioxide concentrations ([CO2]) is widely assumed to increase the net primary productivity (NPP) of C3 plants--the CO2 fertilization effect (CFE). However, the magnitude and persistence of the CFE under future climates, including more frequent weather extremes, are controversial. Here we use data from 16 years of temperate grassland grown under `free-air carbon dioxide enrichment’ conditions to show that the CFE on above-ground biomass is strongest under local average environmental conditions. The observed CFE was reduced or disappeared under wetter, drier and/or hotter conditions when the forcing variable exceeded its intermediate regime. This is in contrast to predictions of an increased CO2 fertilization effect under drier and warmer conditions. Such extreme weather conditions are projected to occur more intensely and frequently under future climate scenarios. Consequently, current biogeochemical models might overestimate the future NPP sink capacity of temperate C3 grasslands and hence underestimate future atmospheric [CO2] increase.

Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees

PubMed Central

Silva, Lucas C. R.; Salamanca-Jimenez, Alveiro; Doane, Timothy A.; Horwath, William R.

2015-01-01

The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases (13CO2 and 15NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the 13CO2 pulse, assimilation and transport of the 15NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history. PMID:26294035

Response to elevated CO2 in the temperate C3 grass Festuca arundinaceae across a wide range of soils

PubMed Central

Nord, Eric A.; Jaramillo, Raúl E.; Lynch, Jonathan P.

2015-01-01

Soils vary widely in mineral nutrient availability and physical characteristics, but the influence of this variability on plant responses to elevated CO2 remains poorly understood. As a first approximation of the effect of global soil variability on plant growth response to CO2, we evaluated the effect of CO2 on tall fescue (Festuca arundinacea) grown in soils representing 10 of the 12 global soil orders plus a high-fertility control. Plants were grown in small pots in continuously stirred reactor tanks in a greenhouse. Elevated CO2 (800 ppm) increased plant biomass in the high-fertility control and in two of the more fertile soils. Elevated CO2 had variable effects on foliar mineral concentration—nitrogen was not altered by elevated CO2, and phosphorus and potassium were only affected by CO2 in a small number of soils. While leaf photosynthesis was stimulated by elevated CO2 in six soils, canopy photosynthesis was not stimulated. Four principle components were identified; the first was associated with foliar minerals and soil clay, and the second with soil acidity and foliar manganese concentration. The third principle component was associated with gas exchange, and the fourth with plant biomass and soil minerals. Soils in which tall fescue did not respond to elevated CO2 account for 83% of global land area. These results show that variation in soil physical and chemical properties have important implications for plant responses to global change, and highlight the need to consider soil variability in models of vegetation response to global change. PMID:25774160

Economic impacts of climate change on agriculture: a comparison of process-based and statistical yield models

NASA Astrophysics Data System (ADS)

Moore, Frances C.; Baldos, Uris Lantz C.; Hertel, Thomas

2017-06-01

A large number of studies have been published examining the implications of climate change for agricultural productivity that, broadly speaking, can be divided into process-based modeling and statistical approaches. Despite a general perception that results from these methods differ substantially, there have been few direct comparisons. Here we use a data-base of yield impact studies compiled for the IPCC Fifth Assessment Report (Porter et al 2014) to systematically compare results from process-based and empirical studies. Controlling for differences in representation of CO2 fertilization between the two methods, we find little evidence for differences in the yield response to warming. The magnitude of CO2 fertilization is instead a much larger source of uncertainty. Based on this set of impact results, we find a very limited potential for on-farm adaptation to reduce yield impacts. We use the Global Trade Analysis Project (GTAP) global economic model to estimate welfare consequences of yield changes and find negligible welfare changes for warming of 1 °C-2 °C if CO2 fertilization is included and large negative effects on welfare without CO2. Uncertainty bounds on welfare changes are highly asymmetric, showing substantial probability of large declines in welfare for warming of 2 °C-3 °C even including the CO2 fertilization effect.

The effect of wood ash fertilization on soil respiration and tree stand growth in boreal peatland forests

NASA Astrophysics Data System (ADS)

Liimatainen, Maarit; Maljanen, Marja; Hytönen, Jyrki

2017-04-01

Out of Finland's original 10 million hectares of peatlands over half has been drained for forestry. Natural peatlands act as a sink for carbon but when peatland is drained, increased oxygen concentration in the peat accelerates the aerobic decomposition of the old organic matter of the peat leading to carbon dioxide (CO2) emissions to atmosphere. Increasing use of bioenergy increases also the amount of ash produced as a byproduct in power plants. Wood ash contains all essential nutrients for trees to grow except nitrogen. Therefore, wood ash is ideal fertilizer for nitrogen rich peatland forests where lack of phosphorus or potassium may restrict tree growth. At the moment, wood ash is the only available PK-fertilizer for peatland forests in Finland and areas of peatland forests fertilized with ash are increasing annually. The effects of wood ash on vegetation, soil properties and tree growth are rather well known although most of the studies have been made using fine ash whereas nowadays mostly stabilized ash (e.g. granulated) is used. Transporting and spreading of stabilized ash is easier than that of dusty fine ash. Also, slower leaching rate of nutrients is environmentally beneficial and prolongs the fertilizer effect. The knowledge on the impact of granulated wood ash on greenhouse gas emissions is still very limited. The aim of this study was to examine the effects of granulated wood ash on CO2 emissions from peat and tree stand growth. Field measurements were done in two boreal peatland forests in 2011 and 2012. One of the sites is more nutrient rich with soil carbon to nitrogen ratio (C/N) of 18 whereas the other site is nutrient poor with C/N ratio of 82. Both sites were fertilized with granulated wood ash in 2003 (5000 kg ha-1). The effect of fertilization was followed with tree stand measurements conducted 0, 5 and 10 years after the fertilization. The CO2 emissions of the decomposing peat (heterotrophic respiration) were measured from study plots where vegetation and litter were removed to eliminate respiration by vegetation (autotrophic respiration). Roots were cut by installing aluminum tubes into the depth of 30 cm. Emissions were measured with chamber method using portable CO2 analyzer. Soil temperature was measured simultaneously with gas measurements manually from the depth of 5 cm as well as continuously with data loggers embedded into the peat. Annual soil respiration was modelled assuming that emissions change as a function of temperature. According to preliminary results, fertilization with granulated wood ash increased CO2 emissions of the peat significantly, especially in nutrient poor site. Ash fertilization increased also strongly the accumulation of carbon into the trees. Nonetheless, in both sites CO2emissions from decomposing peat where higher than carbon that was stored in biomass. This was the case especially in the nutrient poor site where trees are growing poorly and due to low peat nitrogen content the area is not considered suitable for ash fertilization. However, at the more fertile site both stand C sequestration and soil C efflux increased similarly.

Effects of elevated CO2 and N fertilization on soil respiration from ponderosa pine (Pine ponderosa) in open-top chambers

Treesearch

James M. Vose; Katherine J. Elliott; Dale W. Johnson; Roger F. Walker; Mark G. Johnson; David T. Tingey

1995-01-01

We measured growing season soil CO2 evolution under elevated atmospheric CO2 and soil nitrogen (N) additions. Our objectives were to determine treatment effects, quantify seasonal variation, and determine regulating mechanisms. Elevated CO2 treatments were applied in open-top chambers containing 3-...

Nitrogen-mediated effects of elevated CO2 on intra-aggregate soil pore structure

USDA-ARS?s Scientific Manuscript database

While previous elevated atmospheric CO2 research has addressed changes in belowground processes, its effects on soil structure remain virtually undescribed. This study examined the long-term effects of elevated CO2 and N fertilization on soil structural changes in a bahiagrass pasture grown on a san...

Greenhouse gas emissions from solid and liquid organic fertilizers applied to lettuce

USDA-ARS?s Scientific Manuscript database

Excessive and improper application of nitrogen (N) fertilizer, and environmental factors can cause the loss of carbon dioxide (CO2) and nitrous oxide (N2O) to the environment. Also, different types of fertilizers may have different effects on the environment. The focus of this study was to evaluate ...

Amazon rainforest responses to elevated CO2: Deriving model-based hypotheses for the AmazonFACE experiment

NASA Astrophysics Data System (ADS)

Rammig, A.; Fleischer, K.; Lapola, D.; Holm, J.; Hoosbeek, M.

2017-12-01

Increasing atmospheric CO2 concentration is assumed to have a stimulating effect ("CO2 fertilization effect") on forest growth and resilience. Empirical evidence, however, for the existence and strength of such a tropical CO2 fertilization effect is scarce and thus a major impediment for constraining the uncertainties in Earth System Model projections. The implications of the tropical CO2 effect are far-reaching, as it strongly influences the global carbon and water cycle, and hence future global climate. In the scope of the Amazon Free Air CO2 Enrichment (FACE) experiment, we addressed these uncertainties by assessing the CO2 fertilization effect at ecosystem scale. AmazonFACE is the first FACE experiment in an old-growth, highly diverse tropical rainforest. Here, we present a priori model-based hypotheses for the experiment derived from a set of 12 ecosystem models. Model simulations identified key uncertainties in our understanding of limiting processes and derived model-based hypotheses of expected ecosystem responses to elevated CO2 that can directly be tested during the experiment. Ambient model simulations compared satisfactorily with in-situ measurements of ecosystem carbon fluxes, as well as carbon, nitrogen, and phosphorus stocks. Models consistently predicted an increase in photosynthesis with elevated CO2, which declined over time due to developing limitations. The conversion of enhanced photosynthesis into biomass, and hence ecosystem carbon sequestration, varied strongly among the models due to different assumptions on nutrient limitation. Models with flexible allocation schemes consistently predicted an increased investment in belowground structures to alleviate nutrient limitation, in turn accelerating turnover rates of soil organic matter. The models diverged on the prediction for carbon accumulation after 10 years of elevated CO2, mainly due to contrasting assumptions in their phosphorus cycle representation. These differences define the expected response ratio to elevated CO2 at the AmazonFACE site and identify priorities for experimental work and model development.

The evaluation of polycyclic aromatic hydrocarbons (PAHs) biodegradation kinetics in soil amended with organic fertilizers and bulking agents.

PubMed

Włóka, Dariusz; Placek, Agnieszka; Rorat, Agnieszka; Smol, Marzena; Kacprzak, Małgorzata

2017-11-01

The aim of this study was to investigate the polycyclic aromatic hydrocarbons (PAHs) biodegradation kinetics in soils fertilized with organic amendments (sewage sludge, compost), bulking agents (mineral sorbent, silicon dioxide in form of nano powder), and novel compositions of those materials. The scope of conducted works includes a cyclic CO 2 production measurements and the determinations of PAHs content in soil samples, before and after 3-months of incubation. Obtained results show that the use of both type of organic fertilizers have a positive effect on the PAHs removal from soil. However, the CO 2 emission remains higher only in the first stage of the process. The best acquired means in terms of PAHs removal as well as most sustained CO 2 production were noted in samples treated with the mixtures of organic fertilizers and bulking agents. In conclusion the addition of structural forming materials to the organic fertilizers was critical for the soil bioremediation efficiency. Therefore, the practical implementation of collected data could find a wide range of applications during the design of new, more effective solutions for the soil bioremediation purposes. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of tillage and nitrogen fertilizers on CH4 and CO2 emissions and soil organic carbon in paddy fields of central China.

PubMed

Cheng-Fang, Li; Dan-Na, Zhou; Zhi-Kui, Kou; Zhi-Sheng, Zhang; Jin-Ping, Wang; Ming-Li, Cai; Cou-Gui, Cao

2012-01-01

Quantifying carbon (C) sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT) and no-tillage (NT)] and the application of nitrogen (N) fertilizer (0 and 210 kg N ha(-1)) on fluxes of CH(4) and CO(2), and soil organic C (SOC) sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH(4) emissions by 13%-66% and SOC by 21%-94% irrespective of soil sampling depths, but had no effect on CO(2) emissions in either year. Tillage significantly affected CH(4) and CO(2) emissions, where NT significantly decreased CH(4) emissions by 10%-36% but increased CO(2) emissions by 22%-40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%-48% in the 0-5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0-20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered.

New technologies reduce greenhouse gas emissions from nitrogenous fertilizer in China

PubMed Central

Dou, Zheng-xia; He, Pan; Ju, Xiao-Tang; Powlson, David; Chadwick, Dave; Norse, David; Lu, Yue-Lai; Zhang, Ying; Wu, Liang; Chen, Xin-Ping; Cassman, Kenneth G.; Zhang, Fu-Suo

2013-01-01

Synthetic nitrogen (N) fertilizer has played a key role in enhancing food production and keeping half of the world’s population adequately fed. However, decades of N fertilizer overuse in many parts of the world have contributed to soil, water, and air pollution; reducing excessive N losses and emissions is a central environmental challenge in the 21st century. China’s participation is essential to global efforts in reducing N-related greenhouse gas (GHG) emissions because China is the largest producer and consumer of fertilizer N. To evaluate the impact of China’s use of N fertilizer, we quantify the carbon footprint of China’s N fertilizer production and consumption chain using life cycle analysis. For every ton of N fertilizer manufactured and used, 13.5 tons of CO2-equivalent (eq) (t CO2-eq) is emitted, compared with 9.7 t CO2-eq in Europe. Emissions in China tripled from 1980 [131 terrogram (Tg) of CO2-eq (Tg CO2-eq)] to 2010 (452 Tg CO2-eq). N fertilizer-related emissions constitute about 7% of GHG emissions from the entire Chinese economy and exceed soil carbon gain resulting from N fertilizer use by several-fold. We identified potential emission reductions by comparing prevailing technologies and management practices in China with more advanced options worldwide. Mitigation opportunities include improving methane recovery during coal mining, enhancing energy efficiency in fertilizer manufacture, and minimizing N overuse in field-level crop production. We find that use of advanced technologies could cut N fertilizer-related emissions by 20–63%, amounting to 102–357 Tg CO2-eq annually. Such reduction would decrease China’s total GHG emissions by 2–6%, which is significant on a global scale. PMID:23671096

New technologies reduce greenhouse gas emissions from nitrogenous fertilizer in China.

PubMed

Zhang, Wei-Feng; Dou, Zheng-Xia; He, Pan; Ju, Xiao-Tang; Powlson, David; Chadwick, Dave; Norse, David; Lu, Yue-Lai; Zhang, Ying; Wu, Liang; Chen, Xin-Ping; Cassman, Kenneth G; Zhang, Fu-Suo

2013-05-21

Synthetic nitrogen (N) fertilizer has played a key role in enhancing food production and keeping half of the world's population adequately fed. However, decades of N fertilizer overuse in many parts of the world have contributed to soil, water, and air pollution; reducing excessive N losses and emissions is a central environmental challenge in the 21st century. China's participation is essential to global efforts in reducing N-related greenhouse gas (GHG) emissions because China is the largest producer and consumer of fertilizer N. To evaluate the impact of China's use of N fertilizer, we quantify the carbon footprint of China's N fertilizer production and consumption chain using life cycle analysis. For every ton of N fertilizer manufactured and used, 13.5 tons of CO2-equivalent (eq) (t CO2-eq) is emitted, compared with 9.7 t CO2-eq in Europe. Emissions in China tripled from 1980 [131 terrogram (Tg) of CO2-eq (Tg CO2-eq)] to 2010 (452 Tg CO2-eq). N fertilizer-related emissions constitute about 7% of GHG emissions from the entire Chinese economy and exceed soil carbon gain resulting from N fertilizer use by several-fold. We identified potential emission reductions by comparing prevailing technologies and management practices in China with more advanced options worldwide. Mitigation opportunities include improving methane recovery during coal mining, enhancing energy efficiency in fertilizer manufacture, and minimizing N overuse in field-level crop production. We find that use of advanced technologies could cut N fertilizer-related emissions by 20-63%, amounting to 102-357 Tg CO2-eq annually. Such reduction would decrease China's total GHG emissions by 2-6%, which is significant on a global scale.

Effects of elevated seawater pCO2 on early development of scallop Argopecten irradias (Lamarck, 1819)

NASA Astrophysics Data System (ADS)

Wang, Weimin; Liu, Guangxing; Zhang, Tianwen; Chen, Hongju; Tang, Liao; Mao, Xuewei

2016-12-01

To investigate the effects of elevated seawater pCO2 on the early developmental stages of marine benthic calcifying organisms, we exposed the eggs and larvae of Argopecten irradias, an important bivalve species in Chinese aquaculture, in seawater equilibrated with CO2-enriched (1000 ppm) gas mixtures. We demonstrated that elevated seawater pCO2 significantly interfered with fertilization and larval development and resulted in an increased aberration rate. Fertilization in the treatment (pH 7.6) was 74.3% ± 3.8%, which was 9.7% lower than that in the control (pH 8.3) (84.0% ±3.0%). Hatching success decreased by 23.7%, and aberration rate increased by 30.3% under acidic condition. Larvae in acidified seawater still developed a shell during the post-embryonic phase. However, the shell length and height in the treatment were smaller than those in the control. The development of embryos differed significantly at 12 h after fertilization between the two experimental groups. Embryos developed slower in acidified seawater. Nearly half of the embryos in the control developed into D-shaped larvae at 48 h after fertilization, which were considerably more than those in the treatment (11.7%). Results suggest that future ocean acidification (OA) would cause detrimental effects on the early development of A. irradias.

Contribution of nitrous oxide and methan to the overall climate impact of maize on well-drained sandy soils of north-east Germany

NASA Astrophysics Data System (ADS)

Andres, M.; Hagemann, U.; Pohl, M.; Sommer, M.; Augustin, J.

2012-04-01

Erosion effects and the influence of organic fertiliser (fermentation residues, FR) on the climate impact and greenhouse gas (GHG) emissions of N2O, CH4 and CO2 were investigated at an experimental field side in the lowlands of north-east Germany during the years 2010 and 2011. This intensively used agricultural landscape is glacially shaped and characterized by well-drained sandy and loamy soils. Erosion effects on GHG exchange were investigated for energy maize at the CarboZALF-D project site near Dedelow, Uckermark. In addition to a non-eroded haplic luvisol (reference), emissions were measured for three eroded soil types: a) eroded haplic luvisol, b) haplic regosol (calcaric) and c) endogleyic colluvic regosol (deposition side). In a second field trial, the impact of organic fertilization on GHG emissions was assessed for a range of FR fertilization (0-200% N) and compared to a non-fertilized and a minerally fertilized control. Only 70% of the N content of the FR was assumed to be available for plants. Discontinuous measurements of N2O and CH4 were carried out bi-weekly using the closed-chamber method and 20-minute interval sampling. Gas samples were analysed using a gas chromatograph. Gas fluxes were calculated using linear regression, interpolated and finally cumulated. CO2 flux measurements of ecosystem respiration (Reco) and net ecosystem exchange (NEE) were conducted every four weeks by using a non-flow-through non-steady-state closed chamber system (Livingston and Hutchinson 1995) based on Drösler (2005). Measurement gaps of NEE were filled by modeling the Reco fluxes using the Lloyd-Taylor (Lloyd and Taylor 1994) method and the gross primary production (GPP) fluxes using Michaelis-Menten (Michaelis and Menten 1913) modeling approach. Annual NEE balances were then calculated based on the modeled Reco and GPP fluxes. All investigated soil types were C sinks, storing up to 9,6 t CO2eq ha-1 yr-1. As expected for this well-drained soils, the climate impact of CH4 emissions was negligible on all plots with mineral and organic fertilization (-0,05 t CO2eq ha-1 yr-1 up to 0,01 t CO2eq ha-1 yr-1). On minerally fertilized plots, contribution of N2O emissions were very different and varied between 10% and 43% to the overall climate impact (-9,6 t CO2eq ha-1 yr-1 to -2,3 t CO2eq ha-1 yr-1). The highest amount was investigated on the deposition plot. For organic fertilization, N2O emissions increased moderate from 0,02 t CO2eq ha-1 yr-1 (non-fertilized control) with increasing amount of fertilizer to 1,5 t CO2eq ha-1 yr-1. In contrast to N fertilizer application, the contribution of N2O and CH4 to the overall climate impact of eroded agriculturally soils in the glacially shaped landscape is very heterogeneous. Drösler, M. 2005. Trace Gas Exchange and climatic relevance of bog ecosystems, Southern Germany, phD-thesis, TU München, München Livingston, G.P. & Hutchinson, G.L. 1995. Enclosure-based measurement of trace gas exchange: Applications and sources of error. p. 14-51. In P.A. Matson & Harriss, R.C. (ed.) Methods in ecology - Biogenic trace gases: Measuring emissions from soil and water. Blackwell Science, Oxford, England

Impact of mesophyll diffusion on estimated global land CO 2 fertilization

DOE PAGES

Sun, Ying; Gu, Lianhong; Dickinson, Robert E.; ...

2014-10-13

In C 3 plants, CO 2 concentrations drop considerably along mesophyll diffusion pathways from substomatal cavities to chloroplasts where CO 2 assimilation occurs. Global carbon cycle models have not explicitly represented this internal drawdown and so overestimate CO 2 available for carboxylation and underestimate photosynthetic responsiveness to atmospheric CO 2. An explicit consideration of mesophyll diffusion increases the modeled cumulative CO 2 fertilization effect (CFE) for global gross primary production (GPP) from 915 PgC to 1057 PgC for the period of 1901 to 2010. This increase represents a 16% correction, large enough to explain the persistent overestimation of growth ratesmore » of historical atmospheric CO 2 by Earth System Models. Without this correction, the CFE for global GPP is underestimated by 0.05 PgC yr -1ppm -1. This finding implies that the contemporary terrestrial biosphere is more CO 2-limited than previously thought.« less

Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization

USGS Publications Warehouse

Smith, W. Kolby; Reed, Sasha C.; Cleveland, Cory C.; Ballantyne, Ashley P; Anderegg, William R. L.; Wieder, William R.; Liu, Yi Y; Running, Steven W.

2015-01-01

Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (that is, ‘CO2 fertilization’). Here, we present a new satellite-derived global terrestrial NPP data set, which shows a significant increase in NPP from 1982 to 2011. However, comparison against Earth system model (ESM) NPP estimates reveals a significant divergence, with satellite-derived increases (2.8 ± 1.50%) less than half of ESM-derived increases (7.6  ±  1.67%) over the 30-year period. By isolating the CO2 fertilization effect in each NPP time series and comparing it against a synthesis of available free-air CO2 enrichment data, we provide evidence that much of the discrepancy may be due to an over-sensitivity of ESMs to atmospheric [CO2], potentially reflecting an under-representation of climatic feedbacks and/or a lack of representation of nutrient constraints. Our understanding of CO2 fertilization effects on NPP needs rapid improvement to enable more accurate projections of future C cycle–climate feedbacks; we contend that better integration of modelling, satellite and experimental approaches offers a promising way forward.

Synergy of rising nitrogen depositions and atmospheric CO2 on land carbon uptake moderately offsets global warming

NASA Astrophysics Data System (ADS)

Churkina, Galina; Brovkin, Victor; von Bloh, Werner; Trusilova, Kristina; Jung, Martin; Dentener, Frank

2009-12-01

Increased carbon uptake of land in response to elevated atmospheric CO2 concentration and nitrogen deposition could slow down the rate of CO2 increase and facilitate climate change mitigation. Using a coupled model of climate, ocean, and land biogeochemistry, we show that atmospheric nitrogen deposition and atmospheric CO2 have a strong synergistic effect on the carbon uptake of land. Our best estimate of the global land carbon uptake in the 1990s is 1.34 PgC/yr. The synergistic effect could explain 47% of this carbon uptake, which is higher than either the effect of increasing nitrogen deposition (29%) or CO2 fertilization (24%). By 2030, rising carbon uptake on land has a potential to reduce atmospheric CO2 concentration by about 41 ppm out of which 16 ppm reduction would come from the synergetic response of land to the CO2 and nitrogen fertilization effects. The strength of the synergy depends largely on the cooccurrence of high nitrogen deposition regions with nonagricultural ecosystems. Our study suggests that reforestation and sensible ecosystem management in industrialized regions may have larger potential for climate change mitigation than anticipated.

SOIL RESPIRATION RESPONSE TO THREE YEARS OF ELEVATED CO-2 AND N FERTILIZATION IN PONDEROSA PINE (PINUS PONDEROSA DOUG. EX LAWS.)

EPA Science Inventory

We measured growing season soil CO-2 evolution under elevated atmospheric (CO-2) and soil nitrogen (N) additions. Our objectives were to determine treatment effects, quantify seasonal variation, and compare two measurement techniques. Elevated (CO-2) treatments were applied in op...

Effects of elevated atmospheric CO2 and N fertilization on bahiagrass root distribution

USDA-ARS?s Scientific Manuscript database

The effects of elevated atmospheric CO2 on pasture systems remain understudied in the Southeastern US. A 10-year study of bahiagrass (Paspalum notatum Flüggé) response to elevated CO2 was established in 2005 using open top field chambers on a Blanton loamy sand (loamy siliceous, thermic, Grossarenic...

Increasing drought will diminish the benefits of elevated carbon dioxide for soybean yields across the US Midwest

USDA-ARS?s Scientific Manuscript database

Elevated atmospheric CO2 concentrations ([CO2]) are expected to benefit the production of C3 crops through the CO2 fertilization effect (CFE) by stimulating photosynthesis and by reducing stomatal conductance and transpiration. The latter effect is also widely believed to lead to greater benefits in...

Use of the new Nitrogen Index tier zero to assess the effects of nitrogen fertilizer on N2O emissions from cropping systems in Mexico

USDA-ARS?s Scientific Manuscript database

Mexico is one of the largest users of N fertilizer in the world, and the 2nd largest user in Latin America after Brazil. Across large areas of Mexico, N fertilizers are being over-applied, resulting in lower N use efficiencies. Mexico’s trace gas inventory (in CO2 equivalents) reports that agricultu...

Sensitivity towards elevated pCO2 in great scallop (Pecten maximus Lamarck) embryos and fed larvae

NASA Astrophysics Data System (ADS)

Andersen, Sissel; Grefsrud, Ellen S.; Harboe, Torstein

2017-02-01

The increasing amount of dissolved anthropogenic CO2 has caused a drop in pH values in the open ocean known as ocean acidification. This change in seawater carbonate chemistry has been shown to have a negative effect on a number of marine organisms. Early life stages are the most vulnerable, and especially the organisms that produce calcified structures in the phylum Mollusca. Few studies have looked at effects on scallops, and this is the first study presented including fed larvae of the great scallop (Pecten maximus) followed until day 14 post-fertilization. Fertilized eggs from unexposed parents were exposed to three levels of pCO2 using four replicate units: 465 (ambient), 768 and 1294 µatm, corresponding to pHNIST of 7.94, 7.75 (-0.19 units) and 7.54 (-0.40 units), respectively. All of the observed parameters were negatively affected by elevated pCO2: survival, larval development, shell growth and normal shell development. The latter was observed to be affected only 2 days after fertilization. Negative effects on the fed larvae at day 7 were similar to what was shown earlier for unfed P. maximus larvae. Growth rate in the group at 768 µatm seemed to decline after day 7, indicating that the ability to overcome the environmental change at moderately elevated pCO2 was lost over time. The present study shows that food availability does not decrease the sensitivity to elevated pCO2 in P. maximus larvae. Unless genetic adaptation and acclimatization counteract the negative effects of long term elevated pCO2, recruitment in populations of P. maximus will most likely be negatively affected by the projected drop of 0.06-0.32 units in pH within year 2100.

Effects of Tillage and Nitrogen Fertilizers on CH4 and CO2 Emissions and Soil Organic Carbon in Paddy Fields of Central China

PubMed Central

Zhi-Kui, Kou; Zhi-Sheng, Zhang; Jin-Ping, Wang; Ming-Li, Cai; Cou-Gui, Cao

2012-01-01

Quantifying carbon (C) sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT) and no-tillage (NT)] and the application of nitrogen (N) fertilizer (0 and 210 kg N ha−1) on fluxes of CH4 and CO2, and soil organic C (SOC) sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH4 emissions by 13%–66% and SOC by 21%–94% irrespective of soil sampling depths, but had no effect on CO2 emissions in either year. Tillage significantly affected CH4 and CO2 emissions, where NT significantly decreased CH4 emissions by 10%–36% but increased CO2 emissions by 22%–40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%–48% in the 0–5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0–20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered. PMID:22574109

Climate change in Canadian forests: Effect of global warming and CO2 fertilization on natural populations of black and white spruce

NASA Astrophysics Data System (ADS)

Nelson, E. A.; Thomas, S. C.

2007-12-01

Global increases in temperature and atmospheric CO2 concentration are predicted to enhance tree growth in the short term, but studies of current impacts of climate change on Canada's forests are limited. This study examined the effects of increasing temperature and atmospheric CO2 concentration on tree ring growth in west-central Manitoba and northern Ontario, sampling white spruce (Picea glauca) and black spruce (Picea mariana), respectively. Over 50 tree cores from each site were sampled, analysed for ring-width, cross-dated and detrended, generating a ~100 y chronology for each population. We found a positive correlation between ring-width increment and spring temperatures (April-May: p<0.005) in Ontario. In Manitoba, however, we found a negative correlation between summer temperatures (Jul-Aug: p<0.005) and ring-width increment coincident with a positive relationship with summer precipitation (July: p<0.03). We examined the residuals following a regression with temperature for a positive trend over time, which has been interpreted in prior studies as evidence for a CO2 fertilization effect. We detected no such putative CO2 fertilization signal in either spruce population. Our results suggest that temperature-limited lowland black spruce communities may respond positively to moderate warming, but that water-limited upland white spruce communities may suffer from drought stress under high temperature conditions. Neither population appears to benefit from increasing CO2 availability.

Dynamic constraints on CO2 uptake by an iron-fertilized Antarctic

NASA Technical Reports Server (NTRS)

Peng, Tsung-Hung; Broecker, Wallace S.; Oestlund, H. G.

1992-01-01

The topics covered include the following: tracer distribution and dynamics in the Antarctic Ocean; a model of Antarctic and Non-Antarctic Oceans; effects on an anthropogenically affected atmosphere; effects of seasonal iron fertilization; and implications of the South Atlantic Ventilation Experiment C-14 results.

Soil respiration response to three years of elevated CO2 and N fertilization in ponderosa pine (Pinus ponderosa Doug. ex Laws.)

Treesearch

James M. Vose; Katherine J. Elliott; Dale W. Johnson; David T. Tingey; Mark G. Johnson

1997-01-01

We measured growing season soil CO2 evolution under elevated atmospheric [CO2 and soil nitrogen (N) additions. Our objectives were to determine treatment effects, quantify seasonal variation, and compare two measurement techniques. Elevated [CO2] treatments were applied in open-top chambers...

Response of Quercus velutina growth and water use efficiency to climate variability and nitrogen fertilization in a temperate deciduous forest in the northeastern USA.

PubMed

Jennings, Katie A; Guerrieri, Rossella; Vadeboncoeur, Matthew A; Asbjornsen, Heidi

2016-04-01

Nitrogen (N) deposition and changing climate patterns in the northeastern USA can influence forest productivity through effects on plant nutrient relations and water use. This study evaluates the combined effects of N fertilization, climate and rising atmospheric CO2on tree growth and ecophysiology in a temperate deciduous forest. Tree ring widths and stable carbon (δ(13)C) and oxygen (δ(18)O) isotopes were used to assess tree growth (basal area increment, BAI) and intrinsic water use efficiency (iWUE) ofQuercus velutinaLamb., the dominant tree species in a 20+ year N fertilization experiment at Harvard Forest (MA, USA). We found that fertilized trees exhibited a pronounced and sustained growth enhancement relative to control trees, with the low- and high-N treatments responding similarly. All treatments exhibited improved iWUE over the study period (1984-2011). Intrinsic water use efficiency trends in the control trees were primarily driven by changes in stomatal conductance, while a stimulation in photosynthesis, supported by an increase in foliar %N, contributed to enhancing iWUE in fertilized trees. All treatments were predominantly influenced by growing season vapor pressure deficit (VPD), with BAI responding most strongly to early season VPD and iWUE responding most strongly to late season VPD. Nitrogen fertilization increasedQ. velutinasensitivity to July temperature and precipitation. Combined, these results suggest that ambient N deposition in N-limited northeastern US forests has enhanced tree growth over the past 30 years, while rising ambient CO2has improved iWUE, with N fertilization and CO2having synergistic effects on iWUE. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

EFFECTS OF ELEVATED CO2 AND N-FERTILIZATION ON SURVIVAL OF PONDEROSA PINE FINE ROOTS

EPA Science Inventory

We used minihizaotrons to assess the effects of elevated CO2N and season on the life-span of ponderosa pine (Pinus ponderosa Dougl. Ex Laws.) fine roots. CO2 levels were ambient air (A), ambient air + 175 ?mol mol-1 (A+175) and ambient air + 350 ?mol mol-1 (A+350). N treatments ...

Interactive effects between nitrogen fertilization and elevated CO2 on growth and gas exchange of papaya seedling

USDA-ARS?s Scientific Manuscript database

Elevation of CO2 in the atmosphere will change requirements for minerals, mainly nitrogen, altering the relationship between nutrients demand and growth of the plants. We evaluated the interacting effects between CO2 concentrations (390 or 750 µL L-1) and nitrogen levels (3mM or 8mM) on the growth, ...

Climate change impacts on crop yield and quality with CO2 fertilization in China

PubMed Central

Erda, Lin; Wei, Xiong; Hui, Ju; Yinlong, Xu; Yue, Li; Liping, Bai; Liyong, Xie

2005-01-01

A regional climate change model (PRECIS) for China, developed by the UK's Hadley Centre, was used to simulate China's climate and to develop climate change scenarios for the country. Results from this project suggest that, depending on the level of future emissions, the average annual temperature increase in China by the end of the twenty-first century may be between 3 and 4 °C. Regional crop models were driven by PRECIS output to predict changes in yields of key Chinese food crops: rice, maize and wheat. Modelling suggests that climate change without carbon dioxide (CO2) fertilization could reduce the rice, maize and wheat yields by up to 37% in the next 20–80 years. Interactions of CO2 with limiting factors, especially water and nitrogen, are increasingly well understood and capable of strongly modulating observed growth responses in crops. More complete reporting of free-air carbon enrichment experiments than was possible in the Intergovernmental Panel on Climate Change's Third Assessment Report confirms that CO2 enrichment under field conditions consistently increases biomass and yields in the range of 5–15%, with CO2 concentration elevated to 550 ppm Levels of CO2 that are elevated to more than 450 ppm will probably cause some deleterious effects in grain quality. It seems likely that the extent of the CO2 fertilization effect will depend upon other factors such as optimum breeding, irrigation and nutrient applications. PMID:16433100

Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere.

PubMed

Cleveland, Cory C; Townsend, Alan R

2006-07-05

Terrestrial biosphere-atmosphere carbon dioxide (CO(2)) exchange is dominated by tropical forests, where photosynthetic carbon (C) uptake is thought to be phosphorus (P)-limited. In P-poor tropical forests, P may also limit organic matter decomposition and soil C losses. We conducted a field-fertilization experiment to show that P fertilization stimulates soil respiration in a lowland tropical rain forest in Costa Rica. In the early wet season, when soluble organic matter inputs to soil are high, P fertilization drove large increases in soil respiration. Although the P-stimulated increase in soil respiration was largely confined to the dry-to-wet season transition, the seasonal increase was sufficient to drive an 18% annual increase in CO(2) efflux from the P-fertilized plots. Nitrogen (N) fertilization caused similar responses, and the net increases in soil respiration in response to the additions of N and P approached annual soil C fluxes in mid-latitude forests. Human activities are altering natural patterns of tropical soil N and P availability by land conversion and enhanced atmospheric deposition. Although our data suggest that the mechanisms driving the observed respiratory responses to increased N and P may be different, the large CO(2) losses stimulated by N and P fertilization suggest that knowledge of such patterns and their effects on soil CO(2) efflux is critical for understanding the role of tropical forests in a rapidly changing global C cycle.

An Integrated Hydrogen Production-CO2 Capture Process from Fossil Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhicheng Wang

The new technology concept integrates two significant complementary hydrogen production and CO{sub 2}-sequestration approaches that have been developed at Oak Ridge National Laboratory (ORNL) and Clark Atlanta University. The process can convert biomass into hydrogen and char. Hydrogen can be efficiently used for stationary power and mobile applications, or it can be synthesized into Ammonia which can be used for CO{sub 2}-sequestration, while char can be used for making time-release fertilizers (NH{sub 4}HCO{sub 3}) by absorption of CO{sub 2} and other acid gases from exhaust flows. Fertilizers are then used for the growth of biomass back to fields. This projectmore » includes bench scale experiments and pilot scale tests. The Combustion and Emission Lab at Clark Atlanta University has conducted the bench scale experiments. The facility used for pilot scale tests was built in Athens, GA. The overall yield from this process is 7 wt% hydrogen and 32 wt% charcoal/activated carbon of feedstock (peanut shell). The value of co-product activated carbon is about $1.1/GJ and this coproduct reduced the selling price of hydrogen. And the selling price of hydrogen is estimated to be $6.95/GJ. The green house experimental results show that the samples added carbon-fertilizers have effectively growth increase of three different types of plants and improvement ability of keeping fertilizer in soil to avoid the fertilizer leaching with water.« less

Suppression of Native Soil Organic Matter Decomposition by Post-Fermentation Sludge in Agriculture Soil as Assessed by 13C Natural Abundance

NASA Astrophysics Data System (ADS)

Stelmach, W.; Bieganowski, A.; Kuzyakov, Y.

2016-12-01

Anaerobic digestion of organic wastes results in the production of biogas and post-fermentation sludge. Post-fermentation sludge, which is rich in nutrients and contains more easily accessible inorganic-N than comparable composts, can be used as an alternative fertilizer in organic agriculture systems. While the effects of post fermentation sludge application on crop health and productivity have been extensively studied, little is known about its effects on soil parameters and long-term soil health. Thus, the main aim of this study was to determine the effects of post-fermentation sludge fertilization on agriculture soil quality. Specifically, it examined the efficiency and sequence of sludge utilisation by microorganisms and its influence on the utilisation/stabilization of native soil organic matter (SOM).To determine changes in SOM turnover after the addition of sludge, we utilized a natural stable carbon isotope labelling approach. Sludge produced from C4 plant residues (e.g. maize) was applied to soil under C3 cropping, resulting in distinct stable isotope signatures of fertilizer and SOM. Measuring the carbon isotope composition of CO2 produced in this microcosm experiment permitted accurate determination of the proportion of CO2 fluxes arising from both C sources. The addition of post-fermentation sludge increased the CO2 emissions from the soil by 30%. δ13C analysis of the total CO2 efflux revealed that post-fermentation sludge decreased SOM decomposition by 42% compared to control. Only 34% of the post-fermentation sludge had been mineralized after two months of incubation in the soil.The collective results of our study reveal that application of post-fermentation sludge suppresses SOM decomposition, suggesting its use as a fertilizer could positively influence long-term soil quality. Finally, the success of the natural abundance microcosm labeling approach in our study supports its use as an effective method of analyzing the effects of various fertilization techniques on soil nutrient retention.

[Contents of nutrient elements in NH4(+)-N fertilizer and urea].

PubMed

Wang, Zheng-Rui; Qu, Gui-Qin; Rui, Yu-Kui; Shen, Jian-Bo; Zhang, Fu-Suo

2009-03-01

Fertilizer contains not only one compound or one element, so it is important to determine the contents of other elements necessitous and beneficial to plant. All the other nutrient elements for plant, including necessitous elements and beneficial elements in ammonia nitrogen fertilizer ((NH4)2SO4) and CO(NH2)2, were analyzed by method of ICP-MS. The results showed that ammonia nitrogen fertilizer ((NH4)2SO4) and CO(NH2)2 both contain many necessitous elements, Mg, P, K, Ca, Mn, Fe, Ni, Cu, Zn and Mo, thereinto the contents of Mg, P, K, Ca, Mn and Fe were on microg x g(-1) the level, and Ni, Cu, Zn and Mo were on the ng x g(-1) level; compared with CO(NH2)2, ammonia nitrogen fertilizer ((NH4)2SO4) contains more necessitous elements and beneficial elements except Mo and Si. All the above elements could influence the results of nitrogen fertilizer efficiency experiments, so pure fertilizer should be used in the future nitrogen fertilizer efficiency experiments and the comparative experiments of different form nitrogen fertilizer.

Coupled effects of straw and nitrogen management on N2O and CH4 emissions of rainfed agriculture in Northwest China

NASA Astrophysics Data System (ADS)

Htun, Yin Min; Tong, Yanan; Gao, Pengcheng; Xiaotang, Ju

2017-05-01

Straw incorporation is a common agricultural practice, but the additional carbon source may increase greenhouse gas emissions by stimulating microbial activity in soil, particularly when straw is applied at the same time as nitrogen (N) fertilizer. We investigated the coupled effects of straw and N fertilizer on greenhouse gas emissions in a rainfed winter wheat-summer fallow system in Northwest China. Simultaneous applications of straw and N fertilizer increased N2O emissions by up to 88%, net greenhouse gas (NGHG) emission and net greenhouse gas intensity (NGHGI) by over 90%, and the N2O emission factor by over 2-fold. When straw was applied before N fertilizer, the emission factor (0.22%) decreased by approximately one-half compared with that for simultaneous applications (0.45%). In addition, early straw incorporation decreased N2O emissions, NGHG, and NGHGI by 35% (0.62 kg N2O-N ha-1 yr-1), 40% (242 kg CO2-eq ha-1 yr-1), and 38% (42 kg CO2-eq t-1 grain), respectively. We identified the period 30-35 days after N fertilization as a crucial period for evaluating the effectiveness of management practices on N2O emissions. The time between straw and fertilizer applications was negatively related to N2O emission (R2 = 0.8031; p < 0.01) but positively related to soil CH4 uptake (R2 = 0.7662; p < 0.01). Therefore, early straw incorporation can effectively mitigate greenhouse gas emissions by reducing N2O flux and increasing soil CH4 uptake without significantly decreasing grain yield.

Impact of nitrogen fertilization on soil-Atmosphere greenhouse gas exchanges in eucalypt plantations with different soil characteristics in southern China.

PubMed

Zhang, Kai; Zheng, Hua; Chen, Falin; Li, Ruida; Yang, Miao; Ouyang, Zhiyun; Lan, Jun; Xiang, Xuewu

2017-01-01

Nitrogen (N) fertilization is necessary to sustain productivity in eucalypt plantations, but it can increase the risk of greenhouse gas emissions. However, the response of soil greenhouse gas emissions to N fertilization might be influenced by soil characteristics, which is of great significance for accurately assessing greenhouse gas budgets and scientific fertilization in plantations. We conducted a two-year N fertilization experiment (control [CK], low N [LN], middle N [MN] and high N [HN] fertilization) in two eucalypt plantations with different soil characteristics (higher and lower soil organic carbon sites [HSOC and LSOC]) in Guangxi, China, and assessed soil-atmosphere greenhouse gas exchanges. The annual mean fluxes of soil CO2, CH4, and N2O were separately 153-266 mg m-2 h-1, -55 --40 μg m-2 h-1, and 11-95 μg m-2 h-1, with CO2 and N2O emissions showing significant seasonal variations. N fertilization significantly increased soil CO2 and N2O emissions and decreased CH4 uptake at both sites. There were significant interactions of N fertilization and SOC level on soil CO2 and N2O emissions. At the LSOC site, the annual mean flux of soil CO2 emission was only significantly higher than the CK treatment in the HN treatment, but, at the HSOC site, the annual mean flux of soil CO2 emission was significantly higher for both the LN (or MN) and HN treatments in comparison to the CK treatment. Under the CK and LN treatments, the annual mean flux of N2O emission was not significantly different between HSOC and LSOC sites, but under the HN treatment, it was significantly higher in the HSOC site than in the LSOC site. Correlation analysis showed that changes in soil CO2 and N2O emissions were significantly related to soil dissolved organic carbon, ammonia, nitrate and pH. Our results suggested significant interactions of N fertilization and soil characteristics existed in soil-atmosphere greenhouse gas exchanges, which should be considered in assessing greenhouse gas budgets and scientific fertilization strategies in eucalypt plantations.

Impact of different fertilizers on carbonate weathering in a typical karst area, Southwest China: a field column experiment

NASA Astrophysics Data System (ADS)

Song, Chao; Liu, Changli; Han, Guilin; Liu, Congqiang

2017-09-01

Carbonate weathering, as a significant vector for the movement of carbon both between and within ecosystems, is strongly influenced by agricultural fertilization, since the addition of fertilizers tends to change the chemical characteristics of soil such as the pH. Different fertilizers may exert a different impact on carbonate weathering, but these discrepancies are as yet not well-known. In this study, a field column experiment was conducted to explore the response of carbonate weathering to the addition of different fertilizers. We compared 11 different treatments, including a control treatment, using three replicates per treatment. Carbonate weathering was assessed by measuring the weight loss of limestone and dolostone tablets buried at the bottom of soil-filled columns. The results show that the addition of urea, NH4NO3, NH4HCO3, NH4Cl and (NH4)2CO3 distinctly increased carbonate weathering, which was attributed to the nitrification of NH4+. The addition of Ca3(PO4)2, Ca-Mg-P and K2CO3 induced carbonate precipitation due to the common ion effect. The addition of (NH4)3PO4 and NaNO3 had a relatively small impact on carbonate weathering in comparison to those five NH4-based fertilizers above. The results of NaNO3 treatment raise a new question: the negligible impact of nitrate on carbonate weathering may result in an overestimation of the impact of N fertilizer on CO2 consumption by carbonate weathering on the regional/global scale if the effects of NO3 and NH4 are not distinguished.

Investigating the relative importance of nitrogen deposition on the 21st century terrestrial carbon sink

NASA Astrophysics Data System (ADS)

O'Sullivan, Michael; Buermann, Wolfgang; Spracklen, Dominick; Arnold, Steve; Gloor, Manuel

2017-04-01

The global terrestrial carbon sink has increased since the start of this century at a time of rapidly growing carbon dioxide emissions from fossil fuel burning. Here we test the hypothesis that increases in nitrogen deposition from fossil fuel burning and linked carbon-nitrogen interactions fertilized terrestrial ecosystems, increasing carbon uptake and storage. Using the dynamic global vegetation model CLM4.5-BGC, we perform factorial analyses, separating the effects of individual drivers to changes in carbon fluxes and sinks. Globally, we find that increases in nitrogen deposition from 1960 to 2010 increased carbon uptake by 1PgC/yr. One third of this increase can be attributed to East Asia alone, with Europe also having a significant contribution. The global, post-2000 anthropogenic nitrogen deposition effect on terrestrial carbon uptake is entirely accounted for from East Asia (increase of 0.05 PgC/yr). We will also quantify the relative effects of various other drivers on carbon exchanges such as CO2 fertilization, climate change, and land-use and land-cover change. This increased nitrogen deposition has served to fertilize the biosphere in recent years, but its influence on carbon sink processes may be rather short-lived due to the short lifetime of atmospheric reactive nitrogen while the influence of increased CO2 emissions (and the CO2 fertilization effect) will last multiple decades, a 'Faustian Bargain'.

The effects of elevated CO2 and nitrogen fertilization on stomatal conductance estimated from 11 years of scaled sap flux measurements at Duke FACE.

PubMed

Ward, Eric J; Oren, Ram; Bell, David M; Clark, James S; McCarthy, Heather R; Kim, Hyun-Seok; Domec, Jean-Christophe

2013-02-01

In this study, we employ a network of thermal dissipation probes (TDPs) monitoring sap flux density to estimate leaf-specific transpiration (E(L)) and stomatal conductance (G(S)) in Pinus taeda (L.) and Liquidambar styraciflua L. exposed to +200 ppm atmospheric CO(2) levels (eCO(2)) and nitrogen fertilization. Scaling half-hourly measurements from hundreds of sensors over 11 years, we found that P. taeda in eCO(2) intermittently (49% of monthly values) decreased stomatal conductance (G(S)) relative to the control, with a mean reduction of 13% in both total E(L) and mean daytime G(S). This intermittent response was related to changes in a hydraulic allometry index (A(H)), defined as sapwood area per unit leaf area per unit canopy height, which decreased a mean of 15% with eCO(2) over the course of the study, due mostly to a mean 19% increase in leaf area (A(L)). In contrast, L. styraciflua showed a consistent (76% of monthly values) reduction in G(S) with eCO(2) with a total reduction of 32% E(L), 31% G(S) and 23% A(H) (due to increased A(L) per sapwood area). For L. styraciflua, like P. taeda, the relationship between A(H) and G(S) at reference conditions suggested a decrease in G(S) across the range of A(H). Our findings suggest an indirect structural effect of eCO(2) on G(S) in P. taeda and a direct leaf level effect in L. styraciflua. In the initial year of fertilization, P. taeda in both CO(2) treatments, as well as L. styraciflua in eCO(2), exhibited higher G(S) with N(F) than expected from shifts in A(H), suggesting a transient direct effect on G(S). Whether treatment effects on mean leaf-specific G(S) are direct or indirect, this paper highlights that long-term treatment effects on G(S) are generally reflected in A(H) as well.

Management practices effects on soil carbon dioxide emission and carbon storage

USDA-ARS?s Scientific Manuscript database

Management practices can influence soil CO2 emission and C content in cropland, which can effect global warming. We examined the effects of combinations of irrigation, tillage, cropping systems, and N fertilization on soil CO2 flux, temperature, water, and C content at the 0 to 20 cm depth from May ...

The impact of CO2-driven ocean acidification on early development and calcification in the sea urchin Strongylocentrotus intermedius.

PubMed

Zhan, Yaoyao; Hu, Wanbin; Zhang, Weijie; Liu, Minbo; Duan, Lizhu; Huang, Xianya; Chang, Yaqing; Li, Cong

2016-11-15

The impact of CO 2 -driven ocean acidification(OA) on early development and calcification in the sea urchin Strongylocentrotus intermedius cultured in northern Yellow Sea was investigated by comparing fertilization success, early cleavage rate, hatching rate of blastulae, larvae survival rate at 70h post-fertilization, larval morphology and calcification under present natural seawater condition (pH=8.00±0.03) and three laboratory-controlled acidified conditions (OA 1 , △pH=-0.3units; OA 2 , △pH=-0.4units; OA 3 , △pH=-0.5units) projected by IPCC for 2100. Results showed that pH decline had no effect on the overall fertilization, however, with decreased pH, delayed early embryonic cleavage, reduced hatching rate of blastulae and four-armed larvae survival rate at 70h post-fertilization, impaired larval symmetry, shortened larval spicules, and corrosion spicule structure were observed in all OA-treated groups as compared to control, which indicated that CO 2 -driven OA affected early development and calcification in S. intermedius negatively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Long tree-ring chronologies provide evidence of recent tree growth decrease in a Central African tropical forest.

PubMed

Battipaglia, Giovanna; Zalloni, Enrica; Castaldi, Simona; Marzaioli, Fabio; Cazzolla-Gatti, Roberto; Lasserre, Bruno; Tognetti, Roberto; Marchetti, Marco; Valentini, Riccardo

2015-01-01

It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2.

Long Tree-Ring Chronologies Provide Evidence of Recent Tree Growth Decrease in a Central African Tropical Forest

PubMed Central

Battipaglia, Giovanna; Zalloni, Enrica; Castaldi, Simona; Marzaioli, Fabio; Cazzolla- Gatti, Roberto; Lasserre, Bruno; Tognetti, Roberto; Marchetti, Marco; Valentini, Riccardo

2015-01-01

It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2. PMID:25806946

Transient nature of CO2 fertilization in arctic tundra

Treesearch

Walter C. Oechel; Sid Cowles; Nancy Grulke; Steven J. Hastings; Bill Lawrence; Tom Prudhomme; George Riechers; Boyd Strain; David Tissue; George Vourlitis

1994-01-01

There has been much debate about the effect of increased atmospheric CO2 concentrations on plant net primary production1,3 and on net ecosystem CO2 flux3–10. Apparently conflicting experimental findings could be the result of differences in genetic potential11–15...

The influences of CO2 fertilization and land use change on the total aboveground biomass in Amazonian tropical forest

NASA Astrophysics Data System (ADS)

Castanho, A. D.; Zhang, K.; Coe, M. T.; Costa, M. H.; Moorcroft, P. R.

2012-12-01

Field observations from undisturbed old-growth Amazonian forest plots have recently reported on the temporal variation of many of the physical and chemical characteristics such as: physiological properties of leaves, above ground live biomass, above ground productivity, mortality and turnover rates. However, although this variation has been measured, it is still not well understood what mechanisms control the observed temporal variability. The observed changes in time are believed to be a result of a combination of increasing atmospheric CO2 concentration, climate variability, recovery from natural disturbance (drought, wind blow, flood), and increase of nutrient availability. The time and spatial variability of the fertilization effect of CO2 on above ground biomass will be explored in more detail in this work. A precise understanding of the CO2 effect on the vegetation is essential for an accurate prediction of the future response of the forest to climate change. To address this issue we simultaneously explore the effects of climate variability, historical CO2 and land-use change on total biomass and productivity using two different Dynamic Global Vegetation Models (DGVM). We use the Integrated Biosphere Simulator (IBIS) and the Ecosystem Demography Model 2.1 (ED2.1). Using land use changes database from 1700 - 2008 we reconstruct the total carbon balance in the Amazonian forest in space and time and present how the models predict the forest as carbon sink or source and explore why the model and field data diverge from each other. From 1970 to 2005 the Amazonian forest has been exposed to an increase of approximately 50 ppm in the atmospheric CO2 concentration. Preliminary analyses with the IBIS and ED2.1 dynamic vegetation model shows the CO2 fertilization effect could account for an increase in above ground biomass of 0.03 and 0.04 kg-C/m2/yr on average for the Amazon basin, respectively. The annual biomass change varies temporally and spatially from about 0.01 - 0.08 Kg-C/m2/yr, indicating a significant combined effect of the physical environment and climatological variability. The change in biomass due to CO2 fertilization in this study is comparable to the lower limit of the change that has been observed in the field (0.04 - 0.085 kg-C/m2/yr), which suggests that other factors must also be considered to explain the total amount of biomass change observed in the field.

Soil pCO2, soil respiration, and root activity in CO2 - fumigated and nitrogen-fertilized ponderosa pine

Treesearch

Dale Johnson; Donn Geisinger; Roger Walker; John Newman; James Vose; Katherine Elliott; Timothy Ball

1994-01-01

The purpose of this paper is to describe the effects of C02 and N treatments on soil pC02, calculated CO2 efflux, root biomass and soil carbon in open-top chambers planted with Pinus ponderosa seedlings. Based upon the literature, it was hypothesized that both elevated CO...

Long-term Nutrient Fertilization Increases CO2 Loss in Arctic Tundra

NASA Astrophysics Data System (ADS)

Graham, L. M.; Natali, S.; Rastetter, E. B.; Shaver, G. R.; Risk, D. A.; Loranty, M. M.; Jastrow, J. D.

2015-12-01

As anthropogenic climate change warms the Arctic, organic carbon (C) trapped in permafrost is at an increased risk of being released to the atmosphere as carbon dioxide (CO2). At the same time, higher rates of decomposition may increase nutrient availability and enhance plant growth, leading to an uptake of C that may offset respiratory losses. Arctic tundra ecosystems are highly nitrogen (N) limited, and the indirect effects of warming on nutrient availability will be the most likely outcome of increased temperature on plant productivity. This study aims to understand the effects of nutrient addition on arctic CO2 and H2O exchange in a tundra ecosystem at Toolik Lake Field Station, Alaska. The nutrient addition experiment, which began in 2006, is comprised of 7 fertilization treatments: 0.5, 1, 2, 5, and 10 g m-2 of N as NO3- and NH4+ (1:1) with 0.25, 0.5, 1, 2.5, and 5 g m-2 of phosphorus as PO43-; 5 g m-2 of N as NO3-; 5 g m-2 of N as NH4+, and one control plot. Plot-level CO2 and H2O exchange was measured at 5 light levels 7 times over a four-week period in June and July 2015. We measured ecosystem CO2 and H2O exchange using a rectangular plexiglass chamber (0.49 m2) that was connected to an infrared gas analyzer (LI-840). Other ecosystem variables measured include thaw depth, soil moisture and temperature, and normalized difference vegetation index. After 10 years of nutrient addition, fertilization significantly altered ecosystem C cycling. Soil respiration was greatest in the highest fertilization treatment (2.97 μmol m-2 s-1), increasing linearly with nutrient level at a rate of 0.133 μmol m-2 s-1 per g m-2 of N added (R2=0.914). Net CO2 uptake was greatest under highest fertilization (-2.06 μmol m-2 s-1), decreasing linearly with nutrient addition at a rate of -0.068 μmol m-2 s-1 per g m-2 of N added (R2=0.687). These results suggest that as nutrients become more available under a warmer climate, plant productivity increases may not offset respiratory losses, leading to a positive feedback to global climate.

Effects of modification of in vitro fertilization techniques on the sex ratio of the resultant bovine embryos.

PubMed

Iwata, H; Shiono, H; Kon, Y; Matsubara, K; Kimura, K; Kuwayama, T; Monji, Y

2008-05-01

The duration of sperm-oocyte co-incubation has been observed to affect the sex ratio of in vitro produced bovine embryos. The purpose of this study was to investigate some factors that may be responsible for the skewed sex ratio. The factors studied were selected combinations of the duration of co-incubation, the presence or absence of cumulus cells, and the level of hyaluronic acid (HA) in the culture medium. Experiment 1 examined the effect of selected combinations of different factors during the fertilization phase of in vitro oocyte culture. The factors were the nature of the sperm or its treatment, the duration of the sperm-oocyte co-incubation, and the level of hyaluronic acid in the culture medium. In experiment 2, the capacitation of frozen-thawed-Percoll-washed sperm (control), pre-incubated, and non-binding sperm was evaluated by the zona pellucida (ZP) binding assay and the hypo-osmotic swelling test (HOST). The purpose of experiment 3 was to determine the oocyte cleavage rate and sex ratio of the embryos (>5 cells) produced as a consequence of the 10 treatments used in experiment 1. In treatments 1-3 (experiments 1 and 3) COC were co-cultured with sperm for 1, 5 or 18 h. Polyspermic fertilization rose as the co-incubation period increased (1 h 6.5%, 5 h 15.9%, 18 h 41.8%; P<0.05), and the highest rate of normal fertilization was observed for 5h culture (73.4%; P<0.05). The sex ratio was significantly (P<0.05) skewed from the expected 50:50 towards males following 1 h (64.4%) and 5 h (67.3%) co-incubation, but was not affected by 18 h incubation (52.3%). In treatment 4, sperm was pre-incubated for 1h and cultured with COC for 5 h. Relative to control sperm, pre-incubation of sperm increased ZP binding (116 versus 180 per ZP; P<0.05) and decreased the proportion of HOST positive sperm (65.8-48.6%; P<0.05; experiment 2). Pre-incubation did not affect the rates of polyspermy, normal fertilization or the sex ratio of the embryos (experiments 1 and 3). The oocytes used in treatments 5-10 of experiments 1 and 3 were denuded prior to fertilization. Co-incubation of denuded oocytes for 1h (treatment 5) or 5h (treatment 6) resulted in levels of polyspermic fertilization similar to that for treatment 2 with significantly lower levels of normal fertilization (41.7% and 52.6%, respectively; P<0.05), and the 1h co-incubation significantly skewed (P<0.05) the proportion of male embryos to 70.0%. Denuded oocytes were fertilized for 5h with sperm unable to bind to cumulus cells (NB sperm) in treatment 7 or those that bound to cumulus cells (B) in treatment 8. These two treatments had similar rates of polyspermic, normal and non-fertilization. However, the B sperm caused the sex ratio of the embryos to be significantly skewed to males (63.9%; P<0.05). Fertilization of denuded oocytes in medium containing hyaluronic acid (0.1 mg/ml, treatment 9; 1.0 mg/ml treatment 10) significantly (P<0.05) reduced the incidence of polyspermic fertilization relative to treatments 2 and 6, and normal fertilization relative to treatment 2, but did not affect the sex ratio of the embryos. It was concluded that exposure of sperm to cumulus cells, either before fertilization of denuded oocytes or during the process of fertilization of complete COC, increased the proportion of male embryos produced by in vitro culture. It was hypothesized that this may be due to the capacitation state of the sperm, the cumulus-sperm interaction, and/or the ability of the sperm to bind to cumulus cells or oocytes.

Fertilization capacity of cryopreserved Iberian ibex epididymal sperm in a heterologous in vitro fertilization assay.

PubMed

López-Saucedo, J; Santiago-Moreno, J; Fierro, R; Izquierdo, D; Coloma, M A; Catalá, M G; Jiménez, I; Paramio, M T

2015-02-01

In vitro fertilization (IVF) can be used to assess the fertilization capacity of sperm. Heterologous IVF may be useful when assessing that of wild animals as it is often difficult to obtain adequate numbers of naturally corresponding oocytes. The aim of the present study was to assess the fertilization capacity of frozen-thawed ibex epididymal spermatozoa via heterologous IVF involving the oocytes of prepubertal domestic goats. The effect on fertilization and embryo development of adding oestrous sheep serum (ESS) to the fertilization medium was also examined. Cumulus-oocyte complexes (COCs) were matured in TCM-199 for 24-27 h at 38.5°C in a 5% CO2 in air atmosphere. Frozen-thawed epididymal spermatozoa were selected by density gradient centrifugation. After maturation, the oocytes were co-incubated with spermatozoa in synthetic oviductal fluid (SOF) with different concentrations of ESS: SOF-C (0%), SOF-2 (2%) and SOF-20 (20%). At 17 h post-insemination (hpi), zygotes with one female and one male pronucleus (2PN) were categorised as normal; zygotes with 3PN were recorded as polyspermic, and oocytes with 1PN as asynchronous. Cleavage and blastocyst development were assessed at 48 and 168 hpi respectively. The percentage of zygotes with 2PN was higher in the SOF-2 than in the SOF-20 treatment group (27.7% versus 2.9% P < 0.05). The percentage of blastocysts formed with the SOF-C, SOF-2 and SOF-20 treatments were 1.1%, 7.5% and 0% respectively. These results show that the presence of 2% ESS achieves better results than the use of no serum or the standard 20% concentration. Heterologous IVF may be an effective method for predicting the fertilization capacity of ibex spermatozoa, and therefore perhaps that of other wild mountain ungulates.

Greenhouse gas emissions and plant characteristics from soil cultivated with sunflower (Helianthus annuus L.) and amended with organic or inorganic fertilizers.

PubMed

López-Valdez, F; Fernández-Luqueño, F; Luna-Suárez, S; Dendooven, L

2011-12-15

Agricultural application of wastewater sludge has become the most widespread method of disposal, but the environmental effects on soil, air, and crops must be considered. The effect of wastewater sludge or urea on sunflower's (Helianthus annuus L.) growth and yield, the soil properties, and the resulting CO(2) and N(2)O emissions are still unknown. The objectives of this study were to investigate: i) the effect on soil properties of organic or inorganic fertilizer added to agricultural soil cultivated with sunflower, ii) how urea or wastewater sludge increases CO(2) and N(2)O emissions from agricultural soil over short time periods, and iii) the effect on plant characteristics and yield of urea or wastewater sludge added to agricultural soil cultivated with sunflower. The sunflower was fertilized with wastewater sludge or urea or grown in unamended soil under greenhouse conditions while plant and soil characteristics, yield, and greenhouse gas emissions were monitored. Sludge and urea modified some soil characteristics at the onset of the experiment and during the first two months but not thereafter. Some plant characteristics were improved by sludge. Urea and sludge treatments increased the yield at similar rates, while sludge-amended soil significantly increased N(2)O emissions but not CO(2) emissions compared to the other amended or unamended soils. This implies that wastewater sludge increased the biomass and/or the yield; however, from a holistic point of view, using wastewater sludge as fertilizer should be viewed with concern. Copyright © 2011 Elsevier B.V. All rights reserved.

Impact of atmospheric and terrestrial CO2 feedbacks on fertilization-induced marine carbon uptake

NASA Astrophysics Data System (ADS)

Oschlies, A.

2009-04-01

The sensitivity of oceanic CO2 uptake to alterations in the marine biological carbon pump, such as brought about by natural or purposeful ocean fertilization, has repeatedly been investigated by studies employing numerical biogeochemical ocean models. It is shown here that the results of such ocean-centered studies are very sensitive to the assumption made about the response of the carbon reservoirs on the atmospheric side of the sea surface. Assumptions made include prescribed atmospheric pCO2, an interactive atmospheric CO2 pool exchanging carbon with the ocean but not with the terrestrial biosphere, and an interactive atmosphere that exchanges carbon with both oceanic and terrestrial carbon pools. The impact of these assumptions on simulated annual to millennial oceanic carbon uptake is investigated for a hypothetical increase in the C:N ratio of the biological pump and for an idealized enhancement of phytoplankton growth. Compared to simulations with interactive atmosphere, using prescribed atmospheric pCO2 overestimates the sensitivity of the oceanic CO2 uptake to changes in the biological pump, by about 2%, 25%, 100%, and >500% on annual, decadal, centennial, and millennial timescales, respectively. Adding an interactive terrestrial carbon pool to the atmosphere-ocean model system has a small effect on annual timescales, but increases the simulated fertilization-induced oceanic carbon uptake by about 4%, 50%, and 100% on decadal, centennial, and millennial timescales, respectively. On longer than decadal timescales, a substantial fraction of oceanic carbon uptake induced by natural or purposeful ocean fertilization may not come from the atmosphere but from the terrestrial biosphere.

Impact of atmospheric and terrestrial CO2 feedbacks on fertilization-induced marine carbon uptake

NASA Astrophysics Data System (ADS)

Oschlies, A.

2009-08-01

The sensitivity of oceanic CO2 uptake to alterations in the marine biological carbon pump, such as brought about by natural or purposeful ocean fertilization, has repeatedly been investigated by studies employing numerical biogeochemical ocean models. It is shown here that the results of such ocean-centered studies are very sensitive to the assumption made about the response of the carbon reservoirs on the atmospheric side of the sea surface. Assumptions made include prescribed atmospheric pCO2, an interactive atmospheric CO2 pool exchanging carbon with the ocean but not with the terrestrial biosphere, and an interactive atmosphere that exchanges carbon with both oceanic and terrestrial carbon pools. The impact of these assumptions on simulated annual to millennial oceanic carbon uptake is investigated for a hypothetical increase in the C:N ratio of the biological pump and for an idealized enhancement of phytoplankton growth. Compared to simulations with interactive atmosphere, using prescribed atmospheric pCO2 overestimates the sensitivity of the oceanic CO2 uptake to changes in the biological pump, by about 2%, 25%, 100%, and >500% on annual, decadal, centennial, and millennial timescales, respectively. The smaller efficiency of the oceanic carbon uptake under an interactive atmosphere is due to the back flux of CO2 that occurs when atmospheric CO2 is reduced. Adding an interactive terrestrial carbon pool to the atmosphere-ocean model system has a small effect on annual timescales, but increases the simulated fertilization-induced oceanic carbon uptake by about 4%, 50%, and 100% on decadal, centennial, and millennial timescales, respectively, for pCO2 sensitivities of the terrestrial carbon storage in the middle range of the C4MIP models (Friedlingstein et al., 2006). For such sensitivities, a substantial fraction of oceanic carbon uptake induced by natural or purposeful ocean fertilization originates, on timescales longer than decades, not from the atmosphere but from the terrestrial biosphere.

Impact of nitrogen fertilization on soil–Atmosphere greenhouse gas exchanges in eucalypt plantations with different soil characteristics in southern China

PubMed Central

Zhang, Kai; Zheng, Hua; Chen, Falin; Li, Ruida; Yang, Miao; Ouyang, Zhiyun; Lan, Jun; Xiang, Xuewu

2017-01-01

Nitrogen (N) fertilization is necessary to sustain productivity in eucalypt plantations, but it can increase the risk of greenhouse gas emissions. However, the response of soil greenhouse gas emissions to N fertilization might be influenced by soil characteristics, which is of great significance for accurately assessing greenhouse gas budgets and scientific fertilization in plantations. We conducted a two-year N fertilization experiment (control [CK], low N [LN], middle N [MN] and high N [HN] fertilization) in two eucalypt plantations with different soil characteristics (higher and lower soil organic carbon sites [HSOC and LSOC]) in Guangxi, China, and assessed soil–atmosphere greenhouse gas exchanges. The annual mean fluxes of soil CO2, CH4, and N2O were separately 153–266 mg m-2 h-1, -55 –-40 μg m-2 h-1, and 11–95 μg m-2 h-1, with CO2 and N2O emissions showing significant seasonal variations. N fertilization significantly increased soil CO2 and N2O emissions and decreased CH4 uptake at both sites. There were significant interactions of N fertilization and SOC level on soil CO2 and N2O emissions. At the LSOC site, the annual mean flux of soil CO2 emission was only significantly higher than the CK treatment in the HN treatment, but, at the HSOC site, the annual mean flux of soil CO2 emission was significantly higher for both the LN (or MN) and HN treatments in comparison to the CK treatment. Under the CK and LN treatments, the annual mean flux of N2O emission was not significantly different between HSOC and LSOC sites, but under the HN treatment, it was significantly higher in the HSOC site than in the LSOC site. Correlation analysis showed that changes in soil CO2 and N2O emissions were significantly related to soil dissolved organic carbon, ammonia, nitrate and pH. Our results suggested significant interactions of N fertilization and soil characteristics existed in soil–atmosphere greenhouse gas exchanges, which should be considered in assessing greenhouse gas budgets and scientific fertilization strategies in eucalypt plantations. PMID:28192496

Ocean acidification hampers sperm-egg collisions, gamete fusion, and generation of Ca2+ oscillations of a broadcast spawning bivalve, Tegillarca granosa.

PubMed

Shi, Wei; Han, Yu; Guo, Cheng; Zhao, Xinguo; Liu, Saixi; Su, Wenhao; Wang, Yichen; Zha, Shanjie; Chai, Xueliang; Liu, Guangxu

2017-09-01

Although the effect of ocean acidification on fertilization success of marine organisms is increasingly well documented, the underlying mechanisms are not completely understood. The fertilization success of broadcast spawning invertebrates depends on successful sperm-egg collisions, gamete fusion, and standard generation of Ca 2+ oscillations. Therefore, the realistic effects of future ocean pCO 2 levels on these specific aspects of fertilization of Tegillarca granosa were investigated in the present study through sperm velocity trials, fertilization kinetics model analysis, and intracellular Ca 2+ assays, respectively. Results obtained indicated that ocean acidification significantly reduced the fertilization success of T. granosa, which could be accountable by (i) decreased sperm velocity hence reducing the probability for sperm-egg collisions; (ii) lowered probability of gamete fusion for each gamete collision event; and (iii) disrupted intracellular Ca 2+ oscillations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of CO₂ on Acer negundo pollen fertility, protein content, allergenic properties, and carbohydrates.

PubMed

Silva, M; Ribeiro, H; Abreu, I; Cruz, A; Esteves da Silva, J C G

2015-05-01

Atmospheric gaseous pollutants can induce qualitative and quantitative changes in airborne pollen characteristics. In this work, it was investigated the effects of carbon dioxide (CO2) on Acer negundo pollen fertility, protein content, allergenic properties, and carbohydrates. Pollen was collected directly from the anthers and in vitro exposed to three CO2 levels (500, 1000, and 3000 ppm) for 6 and 24 h in an environmental chamber. Pollen fertility was determined using viability and germination assays, total soluble protein was determined with Coomassie Protein Assay Reagent, and the antigenic and allergenic properties were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunological techniques using patients' sera. Also, pollen fructose, sucrose, and glucose values were determined. Carbon dioxide exposure affected negatively pollen fertility, total soluble protein content, and fructose content. The patient sera revealed increased IgE reactivity to proteins of A. negundo pollen exposed to increasing levels of the pollutant. No changes were detected in the SDS-PAGE protein profiles and in sucrose and glucose levels. Our results indicate that increase in atmospheric CO2 concentrations can have a negative influence of some features of A. negundo airborne pollen that can influence the reproductive processes as well as respiratory pollen allergies in the future.

CO2 and fertility affect growth and reproduction but not susceptibility to aphids in field grown Solanum ptycanthum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, T.M.

1995-09-01

In general, C3 annual plants respond positively in terms of growth, reproduction and biomass accrued when grown under elevated levels of atmospheric carbon dioxide. However, most studies documenting this response have been conducted in growth chambers where plants can be reared under conditions free form environmental stressors such as nutrient and water constraints, UV exposure and damage from pests. During the 1993 fieldseason, I grew 200 individuals of Solanum ptycanthum in an array of 10 outdoor, open-topped CO2 enclosures (5 @ 700 ppm CO2) at the University of Michigan Biological Station in Pellston, MI. Half of the plants were grownmore » in a 50;50 mix of native C-horizon soil and topsoil (low fertility); the other half were grown in 100% topsoil (high-fertility). Plants were censused throughout the growing season for flower and fruit production, growth rate and degree of infestation of aphids. Fertility and CO2 both significantly affected production of flowers and fruits, but only fertility was significantly related to vegetative growth. Aphid infestation varied significantly among enclosures, but was not related to CO2 or fertility.« less

Efficiency of small scale carbon mitigation by patch iron fertilization

NASA Astrophysics Data System (ADS)

Sarmiento, J. L.; Slater, R. D.; Dunne, J.; Gnanadesikan, A.; Hiscock, M. R.

2009-11-01

While nutrient depletion scenarios have long shown that the high-latitude High Nutrient Low Chlorophyll (HNLC) regions are the most effective for sequestering atmospheric carbon dioxide, recent simulations with prognostic biogeochemical models have suggested that only a fraction of the potential drawdown can be realized. We use a global ocean biogeochemical general circulation model developed at GFDL and Princeton to examine this and related issues. We fertilize two patches in the North and Equatorial Pacific, and two additional patches in the Southern Ocean HNLC region north of the biogeochemical divide and in the Ross Sea south of the biogeochemical divide. We obtain by far the greatest response to iron fertilization at the Ross Sea site. Here the CO2 remains sequestered on century time-scales and the efficiency of fertilization remains almost constant no matter how frequently iron is applied as long as it is confined to the growing season. The second most efficient site is in the Southern Ocean. Here the biological response to iron fertilization is comparable to the Ross Sea, but the enhanced biological uptake of CO2 is more spread out in the vertical and thus less effective at leading to removal of CO2 from the atmosphere. The North Pacific site has lower initial nutrients and thus a lower efficiency. Fertilization of the Equatorial Pacific leads to an expansion of the suboxic zone and a striking increase in denitrification that causes a sharp reduction in overall surface biological export production and CO2 uptake. The impacts on the oxygen distribution and surface biological export are less prominent at other sites, but nevertheless still a source of concern. The century time scale retention of iron in these models greatly increases the long-term biological response to iron addition as compared with models in which the added iron is rapidly scavenged from the ocean.

Increased resin flow in mature pine trees growing under elevated CO2 and moderate soil fertility

Treesearch

K.A. Novick; G.G. Katul; H.R. McCarthy; R. Oren

2012-01-01

Warmer climates induced by elevated atmospheric CO2 (eCO2) are expected to increase damaging bark beetle activity in pine forests, yet the effect of eCO2 on resin production—the tree’s primary defense against beetle attack—remains largely unknown. Following growth-differentiation balance theory, if extra carbohydrates produced under eCO2 are not consumed by respiration...

Long-term CO2 rise has increased photosynthetic efficiency and water use efficiency but did not stimulate diameter growth of tropical trees

NASA Astrophysics Data System (ADS)

Groenendijk, P.; Zuidema, P.; Sleen, P. V. D.; Vlam, M.; Ehlers, I.; Schleucher, J.

2014-12-01

Tropical forests are a crucial component of the global carbon cycle, and their responses to atmospheric changes may shift carbon cycling and climate systems. Dynamic Global Vegetation Models (DGVMs) are the major tools to simulate tropical forest responses to climate change. One of the main determinants of these simulated responses is the effect of CO2 on tropical tree physiology and growth, the 'CO2 fertilization effect'. The paucity of CO2 enrichment experiments in the tropics importantly limits insights into the CO2 fertilization effect as well as the validation of DGVMs. However, use can be made of the 40% rise in atmospheric CO2 concentration since the onset of the Industrial Revolution. The effects of the historical CO2 rise on tree physiology and growth can be obtained from stable isotopes, isotopomers and tree diameter increments obtained in tree-ring studies. We studied the physiological and growth responses of 12 tree species in Bolivia, Cameroon and Thailand to 150 years of CO2 enrichment. Analyses of 13C of wood cellulose revealed strong, long-term increases in leaf intercellular CO2 concentrations for all study species and a marked improvement of intrinsic water use efficiency (iWUE). For a subset of one species per site, we studied the Deuterium isotopomers (isomers with isotopic atoms) of glucose in wood to obtain a direct estimate of the photorespiration-to-photosynthesis ratio. We found that this ratio consistently and strongly decreased over the past century, thus increasing the effeciency and rate of photosynthesis. In spite of these strong physiological responses to increased CO2levels, we did not find evidence for increased tree diameter growth for any of the sites, or for sites combined. Possible reasons for the lack of a growth stimulation include increased (leaf) temperature, insufficient availability of nutrients or a shift in biomass investment in trees. Our results suggest that the strong CO2 fertilization of tropical tree growth often assumed in DGVMs does not hold and that these models may overestimate future biomass production in tropical forests. Empirical information on responses of tropical trees to historical CO2rise as presented here can be used to validate and possibly adapt (components of) DGVMs and improve the projections of tropical forest structure under climate change.

Interactive Effects of Elevated CO2 and N Fertilization on Yield and Quality of Tomato Grown Under Reduced Irrigation Regimes

PubMed Central

Wei, Zhenhua; Du, Taisheng; Li, Xiangnan; Fang, Liang; Liu, Fulai

2018-01-01

The interactive effects of CO2 elevation, N fertilization, and reduced irrigation regimes on fruit yield (FY) and quality in tomato (Solanum lycopersicum L.) were investigated in a split-root pot experiment. The plants were grown in two separate climate-controlled greenhouse cells at atmospheric [CO2] of 400 and 800 ppm, respectively. In each cell, the plants were fertilized at either 100 or 200 mg N kg-1 soil and were either irrigated to full water holding capacity [i.e., a volumetric soil water content of 18%; full irrigation (FI)], or using 70% water of FI to the whole pot [deficit irrigation (DI)] or alternately to only half of the pot [partial root-zone irrigation (PRI)]. The yield and fruit quality attributes mainly from sugars (sucrose, fructose, and glucose) and organic acids (OAs; citric acid and malic acid) to various ionic (NH4+, K+, Mg2+, Ca2+, NO3-, SO42-, and PO43-) concentrations in fruit juice were determined. The results indicated that lower N supply reduced fruit number and yield, whereas it enhanced some of the quality attributes of fruit as indicated by greater firmness and higher concentrations of sugars and OAs. Elevated [CO2] (e[CO2]) attenuated the negative influence of reduced irrigation (DI and PRI) on FY. Principal component analysis revealed that the reduced irrigation regimes, especially PRI, in combination with e[CO2] could synergistically improve the comprehensive quality of tomato fruits at high N supply. These findings provide useful knowledge for sustaining tomato FY and quality in a future drier and CO2-enriched environment. PMID:29636756

Host suitability of Phaseolus lunata for Trichoplusia ni (lepidoptera: noctuidae) in controlled carbon dioxide atmospheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osbrink, W.L.A.; Trumble, J.T.; Wagner, R.E.

1987-06-01

Elevated atmospheric carbon dioxide (CO/sub 2/) levels of 1000 parts per million (ppm) significantly increased consumption of foliage by Trichoplusia ni (Huebner) and significantly enhanced growth of Phaseolus lunata L. when compared with ambient levels of 340 ppm. Mean pupal weight was less under treatments with elevated atmospheric CO/sub 2/ under a high fertilization regime, but larval survival and percent nitrogen content of pupae were not affected by level of CO/sub 2/ treatments at high, medium, or low fertilizer rates. Regardless of CO/sub 2/ concentration, larval survival and pupal weight were reduced in absence of fertilizer. Nitrogen and protein consumptionmore » increased with fertilization rate. Because percent leaf area of plants consumed by T. ni larvae was not affected by CO/sub 2/ concentration, this study suggests that increased plant growth resulting from elevated atmospheric CO/sub 2/ may benefit the plant proportionately more than the insect.« less

Net global warming potential and greenhouse gas intensity influenced by irrigation, tillage, crop rotation, and nitrogen fertilization.

PubMed

Sainju, Upendra M; Stevens, William B; Caesar-TonThat, Thecan; Liebig, Mark A; Wang, Jun

2014-05-01

Little information exists about how global warming potential (GWP) is affected by management practices in agroecosystems. We evaluated the effects of irrigation, tillage, crop rotation, and N fertilization on net GWP and greenhouse gas intensity (GHGI or GWP per unit crop yield) calculated by soil respiration (GWP and GHGI) and organic C (SOC) (GWP and GHGI) methods after accounting for CO emissions from all sources (irrigation, farm operations, N fertilization, and greenhouse gas [GHG] fluxes) and sinks (crop residue and SOC) in a Lihen sandy loam from 2008 to 2011 in western North Dakota. Treatments were two irrigation practices (irrigated vs. nonirrigated) and five cropping systems (conventional-till malt barley [ L.] with N fertilizer [CTBN], conventional-till malt barley with no N fertilizer [CTBO], no-till malt barley-pea [ L.] with N fertilizer [NTB-P], no-till malt barley with N fertilizer, and no-till malt barley with no N fertilizer [NTBO]). While CO equivalents were greater with irrigation, tillage, and N fertilization than without, NO and CH fluxes were 2 to 218 kg CO eq. ha greater in nonirrigated NTBN and irrigated CTBN than in other treatments. Previous year's crop residue and C sequestration rate were 202 to 9316 kg CO eq. ha greater in irrigated NTB-P than in other treatments. Compared with other treatments, GWP and GWP were 160 to 9052 kg CO eq. ha lower in irrigated and nonirrigated NTB-P. Similarly, GHGI and GHGI were lower in nonirrigated NTB-P than in other treatments. Regardless of irrigation practices, NTB-P may lower net GHG emissions more than other treatments in the northern Great Plains. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

-induced fertilization impairment in Strongylocentrotus droebachiensis collected in the Arctic

NASA Astrophysics Data System (ADS)

Bögner, D.; Bickmeyer, U.; Köhler, A.

2014-06-01

Fertilization depends on distribution and aggregation patterns of sea urchins which influence gamete contact time and may potentially enhance their vulnerability to ocean acidification. In this study, we conducted fertilization experiments to assess the effects of selected pH scenarios on fertilization success of Strongylocentrotus droebachiensis, from Spitsbergen, Arctic. Acidification was achieved by aerating seawater with different CO2 partial pressures to represent pre-industrial and present conditions (measured ~180-425 µatm) and future acidification scenarios (~550-800, ~1,300, ~2,000 µatm). Fertilization success was defined as the proportion of successful/unsuccessful fertilizations per treatment; eggs were classified according to features of their fertilization envelope (FE), hyaline layer (HL) and achievement of cellular division. The diagnostic findings of specific pathological aberrations were described in detail. We additionally measured intracellular pH changes in unfertilized eggs exposed for 1 h to selected acidification treatments using BCECF/AM. We conclude that (a) acidified conditions increase the proportion of eggs that failed fertilization, (b) acidification may increase the risk of polyspermy due to failures in the FE formation supported by the occasional observation of multiple sperms in the perivitelline space and (c) irregular formation of the embryo may arise due to impaired formation of the HL. The decrease in fertilization success could be also related to the observed changes in intracellular pH at pCO2 ~ 1,000 μatm or higher.

Effects of the herbicides prosulfuron and metolachlor on fluxes of CO2, N2O, and CH4 in a fertilized Colorado grassland soil

USGS Publications Warehouse

Kinney, C.A.; Mosier, A.R.; Ferrer, I.; Furlong, E.T.; Mandernack, K.W.

2004-01-01

The effect that pesticides have on trace gas production and consumption in agricultural soils is often overlooked. Independent field and laboratory experiments were used to measure the effects that the commonly used herbicides prosulfuron and metolachlor have on trace gas fluxes (CO2, N2O, and CH4) from fertilized soil of the Colorado shortgrass steppe. Separate sample plots (1 m2) on tilled and no-till soil at the sites included the following treatments: 1) a control without fertilizer or herbicide, 2) a fertilized (NH4NO3 equivalent to 244 kg ha-1) control without herbicide, 3) and fertilized plots amended with an herbicide (prosulfuron equivalent to 0.46 kg ha-1 57% by weight active ingredient or metolachlor equivalent to 5.7 L ha-1, 82.4% by weight active ingredient). During an initial study of one year duration, measurement of gas exchange revealed that prosulfuron-amendment stimulated N2O emissions and CH4 consumption by as much as 1600% and 1300% during a single measurement, respectively. During a second set of flux measurements beginning in August 2001, more frequent weekly measurements were made during a twelve week period. From this second study an increased N2O efflux and CH4 uptake occurred after a 7-week lag period that persisted for about 5 weeks. These changes in gas flux amounted to an overall increase of 41% and 30% for N2O emission and CH4 consumption, respectively. The co-occurrence of stimulated N2O and CH4 fluxes suggests a similar cause that is related to prosulfuron degradation. Evidence suggested that prosulfuron degradation stimulated microbial activity responsible for trace gas flux. Ultimately, prosulfuron-amendment led to an ???50% reduction in the global warming potential from N2O and CH4 fluxes at this field site, which is equivalent to a reduction of the global warming potential of 0.18 mols CO2 m-2 d-1 from these gases. Metolachlor application did not significantly affect the trace gas fluxes measured. These results demonstrate the potential impact that pesticides have on trace gas fluxes from agricultural soils, which could mean that the effects of other agricultural practices have been over or under estimated. Copyright 2004 by the American Geophysical Union.

RISING ATMOSPHERIC CO2 AND CARBON SEQUESTRATION IN FORESTS

EPA Science Inventory

Rising CO2 concentrations in the Earth's atmosphere could alter Earth's climate system, but it is thought that higher concentrations may improve plant growth by way of the fertilization effect. Forests, an important part of the Earth's carbon cycle, are postulated to sequester a...

Water availability drives gas exchange and growth of trees in northeastern US, not elevated CO2 and reduced acid deposition.

PubMed

Levesque, Mathieu; Andreu-Hayles, Laia; Pederson, Neil

2017-04-10

Dynamic global vegetation models (DGVM) exhibit high uncertainty about how climate change, elevated atmospheric CO 2 (atm. CO 2 ) concentration, and atmospheric pollutants will impact carbon sequestration in forested ecosystems. Although the individual roles of these environmental factors on tree growth are understood, analyses examining their simultaneous effects are lacking. We used tree-ring isotopic data and structural equation modeling to examine the concurrent and interacting effects of water availability, atm. CO 2 concentration, and SO 4 and nitrogen deposition on two broadleaf tree species in a temperate mesic forest in the northeastern US. Water availability was the strongest driver of gas exchange and tree growth. Wetter conditions since the 1980s have enhanced stomatal conductance, photosynthetic assimilation rates and, to a lesser extent, tree radial growth. Increased water availability seemingly overrides responses to reduced acid deposition, CO 2 fertilization, and nitrogen deposition. Our results indicate that water availability as a driver of ecosystem productivity in mesic temperate forests is not adequately represented in DGVMs, while CO 2 fertilization is likely overrepresented. This study emphasizes the importance to simultaneously consider interacting climatic and biogeochemical drivers when assessing forest responses to global environmental changes.

Humus and energy balances and greenhouse gas emissions with compost fertilization in organic farming compared with mineral fertilization

NASA Astrophysics Data System (ADS)

Erhart, Eva; Schmid, Harald; Hülsbergen, Kurt-Jürgen; Hartl, Wilfried

2015-04-01

Humus and energy balances and greenhouse gas emissions with compost fertilization in organic farming compared with mineral fertilization E. Erhart, H. Schmid, K.-J. Hülsbergen, W. Hartl The positive effects of compost fertilization on soil humus with their associated benefits for soil quality are well-established. The aim of the present study was to assess the effect of compost fertilization on humus and energy balances and greenhouse gas emissions and to compare the results of the humus balances with the changes in soil organic carbon contents measured in the soil of the experimental field. In order to assess the effects of compost use in organic farming as compared to conventional farming practice using mineral fertilizers, the field experiment with compost fertilization 'STIKO' was set up in 1992 near Vienna, Austria, on a Molli-gleyic Fluvisol. It included three treatments with compost fertilization (C1, C2 and C3 with 8, 14 and 20 t ha-1 y-1 f. m. on average of 14 years), three treatments with mineral nitrogen fertilization (N1, N2 and N3 with 29, 46 and 63 kg N ha-1 y 1 on average) and an unfertilized control (0) in six replications in a latin rectangle design. In the field trial, biowaste compost from the composting plant of the City of Vienna was used. Data from the field experiment (from 14 experimental years) were fed into the model software REPRO to calculate humus and energy balances and greenhouse gas emissions. The model software REPRO (REPROduction of soil fertility) couples the balancing of C, N and energy fluxes. For the determination of the net greenhouse effect, REPRO performs calculations of C sequestration in the soil, CO2 emissions from the use of fossil energy and N2O emissions from the soil. Humus balances showed that compost fertilization at a rate of 8 t ha-1 y-1 (C1) resulted in a positive humus balance of +115 kg C ha-1 y-1. With 14 and 20 t ha-1 y-1 compost (C2 and C3), respectively, humus accumulated at rates of 558 and 1021 kg C ha-1 y-1. With mineral fertilization at rates of 29 - 63 kg N ha-1 y-1 (N1 - N3), balances were moderately negative ( 169 to -227 kg C ha-1 y-1), while a clear humus deficit of 457 kg C ha-1 y-1 showed in the unfertilized control. Compared with measured soil organic carbon data REPRO predicted soil organic carbon contents fairly well with the exception of the treatments with high compost rates. Here REPRO clearly overestimated soil organic carbon contents for this site. Energy efficiency, as described by the output/input ratio, was highest in the control, followed by C1. Mineral fertilization treatment N3 was most energy intensive. The greenhouse gas balance indicated net carbon sequestration already with medium compost rates (C2), and net carbon sequestration of 1700 kg CO2-eq ha-1 y-1 in C3. Mineral fertilization yielded net greenhouse gas emissions of around 2000 kg CO2-eq ha-1 y 1. The highest greenhouse gas emissions had the unfertilized control due to the degradation of soil organic matter and lowest organic matter input. These findings underline that compost fertilization holds a high potential for carbon sequestration and for the reduction of greenhouse gas emissions.

Olive oil mill wastewater for soil nitrogen and carbon conservation.

PubMed

Aguilar, Manuel Jimenez

2009-06-01

In this work the application of two levels of N fertilizer (NH(4)NO(3)) dissolved in water or olive oil mill wastewater (OOMW) diluted 10 or 20 times in water, has been studied in relation to the properties of two soils (Loam and Silt-Clay-Loam). Also, the effect of irrigation water bubbled with CO(2) (Dissolved Inorganic Carbon, DIC) was studied. Nitrate N, ammonium N, total N, organic C (OC), and CaCO(3) contents were determined in the soil as well as pH, electrical conductivity (EC), oxidation-reduction potential (ORP), and absorbance at 250 and 360 nm. Our data provide evidence that inorganic-N fertilizer dissolved in OOMW significantly reduced the emission of nitrates from soils for two months, increasing OC values. Moreover, OOMW significantly lowered the ORP. The irrigation with DIC also increased soil OC. Thus, the application of inorganic-N fertilizers dissolved in OOMW diluted with water on soils and the irrigation with water bubbled with CO(2) could reduce the environmental impact of OOMW, nitrates, and CO(2).

Enhancement of Carbon Sequestration in west coast Douglas-fir Forests with Nitrogen Fertilization

NASA Astrophysics Data System (ADS)

Chen, B.; Jassal, R.; Black, A.; Brummer, C.; Spittlehouse, D.; Nesic, Z.

2008-12-01

Fertilization is one of the eligible management practices for C sequestering and hence reducing CO2 emissions under Article 3.4 of the Kyoto Protocol. In the coastal regions of British Columbia, which have very little nitrogen (N) deposition from pollution sources owing to their remote location, and soils deficient in N (Hanley et al., 1996), Douglas-fir stands respond to N fertilization (Brix, 1981; Fisher and Binkley, 2000; Chapin et al., 2002). However, a major concern with N fertilization is the potential loss from the soil surface of the highly potent greenhouse gas N2O, and little is known about such losses in N-fertilized forest soils. While it is necessary to determine and quantify the effects of N fertilization on stand C sequestration, it is also important to address environmental concerns by measuring N2O emissions to determine the net greenhouse gas (GHG) global warming potential (GWP). The GWP of N2O is 296 times (100-year time horizon) greater than that of CO2 (Ehhalt and Prather, 2001), yet there is little information on its net radiative forcing as a result of forest fertilization. We report two years of results on the effects of N fertilization in a chronosequence of three Douglas-fir stands (7, 19 and 58 years old, hereafter referred to as HDF00, HDF88 and DF49, respectively) on net C sequestration or net primary productivity measured using the eddy-covariance technique. DF49 (110 ha) and HDF88 (20 ha) were aerially fertilized with urea at 200 kg N ha-1 on Jan 13 and Feb 17, 2007, respectively, while due to its young age and competing understory, fertilizer to HDF00 (5 ha) was manually applied at 80 g urea/tree (60 kg N ha-1) along the tree drip line on Feb 13-14, 2007. Additionally, we calculate the net change in GHG GWP resulting from fertilization of DF49 by accounting for N2O emissions and energy costs of fertilizer production, transport, and application. We also compare polymer-coated slow-release urea (Environmentally Smart Nitrogen (ESN), Agrium Inc., Calgary, AB, Canada) with regular urea for its potential effectiveness in reducing N2O emissions from the forest-floor.

Effect of Increasing Nitrogen Deposition on Soil Microbial Communities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Shengmu; Xue, Kai; He, Zhili

2010-05-17

Increasing nitrogen deposition, increasing atmospheric CO2, and decreasing biodiversity are three main environmental changes occurring on a global scale. The BioCON (Biodiversity, CO2, and Nitrogen) ecological experiment site at the University of Minnesota's Cedar Creek Ecosystem Science Reserve started in 1997, to better understand how these changes would affect soil systems. To understand how increasing nitrogen deposition affects the microbial community diversity, heterogeneity, and functional structure impact soil microbial communities, 12 samples were collected from the BioCON plots in which nitrogenous fertilizer was added to simulate the effect of increasing nitrogen deposition and 12 samples from without added fertilizer. DNAmore » from the 24 samples was extracted using a freeze-grind protocol, amplified, labeled with a fluorescent dye, and then hybridized to GeoChip, a functional gene array containing probes for genes involved in N, S and C cycling, metal resistance and organic contaminant degradation. Detrended correspondence analysis (DCA) of all genes detected was performed to analyze microbial community patterns. The first two axes accounted for 23.5percent of the total variation. The samples fell into two major groups: fertilized and non-fertilized, suggesting that nitrogenous fertilizer had a significant impact on soil microbial community structure and diversity. The functional gene numbers detected in fertilized samples was less that detected in non-fertilizer samples. Functional genes involving in the N cycling were mainly discussed.« less

Regional contributions of ocean iron fertilization to atmospheric CO2 changes during the last glacial termination

NASA Astrophysics Data System (ADS)

Opazo, N. E.; Lambert, F.

2017-12-01

Mineral dust aerosols affect climate directly by changing the radiative balance of the Earth, and indirectly by acting as cloud condensation nuclei and by affecting biogeochemical cycles. The impact on marine biogeochemical cycles is primarily through the supply of micronutrients such as iron to nutrient-limited regions of the oceans. Iron fertilization of High Nutrient Low Chlorophyll (HNLC) regions of the oceans is thought to have significantly affected the carbon cycle on glacial-interglacial scales and contributed about one fourth of the 80-100 ppm lowering of glacial atmospheric CO2 concentrations.In this study, we quantify the effect of global dust fluxes on atmospheric CO2 using the cGENIE model, an Earth System Model of Intermediate Complexity with emphasis on the carbon cycle. Global Holocene and Last Glacial Maximum (LGM) dust flux fields were obtained from both dust model simulations and reconstructions based on observational data. The analysis was performed in two stages. In the first instance, we produced 8 global intermediate dust flux fields between Holocene and LGM and simulated the atmospheric CO2 drawdown due to these 10 dust levels. In the second stage, we only changed dust flux levels in specific HNLC regions to isolate the effect of these ocean basins. We thus quantify the contribution of the South Atlantic, the South Pacific, the North Pacific, and the Central Pacific HNLC regions to the total atmospheric CO2 difference due to iron fertilization of the Earth's oceans.

[Evaluating the response of yield and evapotranspiration of winter wheat and the adaptation by adjusting crop variety to climate change in Huang-Huai-Hai Plain].

PubMed

Hu, Shi; Mo, Xing-guo; Lin, Zhong-hui

2015-04-01

Based on the multi-model datasets of three representative concentration pathway (RCP) emission scenarios from IPCC5, the response of yield and accumulative evapotranspiration (ET) of winter wheat to climate change in the future were assessed by VIP model. The results showed that if effects of CO2 enrichment were excluded, temperature rise would lead to a reduction in the length of the growing period for wheat under the three climate change scenarios, and the wheat yield and ET presented a decrease tendency. The positive effect of atmospheric CO2 enrichment could offset most negative effect introduced by temperature rising, indicating that atmospheric CO2 enrichment would be the prime reason of the wheat yield rising in future. In 2050s, wheat yield would increase 14.8% (decrease 2.5% without CO2 fertilization) , and ET would decrease 2.1% under RCP4.5. By adoption of new crop variety with enhanced requirement on accumulative temperature, the wheat yield would increase more significantly with CO2 fertilization, but the water consumption would also increase. Therefore, cultivar breeding new irrigation techniques and agronomical management should be explored under the challenges of climate change in the future.

Soil fertility limits carbon sequestration by forest ecosystems in a CO2-enriched atmosphere

Treesearch

Ram Oren; David S. Ellsworth; Kurt H. Johnsen; Nathan Phillips; Brent E. Ewers; Chris Maier; Karina V.R. Schafer; Heather McCarthy; George Hendrey; Steven G. McNulty; Gabriel G. Katul

2001-01-01

Northern mid-latitude forests are a large terrestrial carbon sink. Ignoring nutrient limitations, large increases in carbon sequestration from carbon dioxide (CO2) fertilization are expected in these forests. Yet, forests are usually relegated to sites of moderate to poor fertility, where tree growth is often limited by nutrient supply, in...

Invasive forb benefits from water savings by native plants and carbon fertilization under elevated CO2 and warming.

PubMed

Blumenthal, Dana M; Resco, Víctor; Morgan, Jack A; Williams, David G; Lecain, Daniel R; Hardy, Erik M; Pendall, Elise; Bladyka, Emma

2013-12-01

As global changes reorganize plant communities, invasive plants may benefit. We hypothesized that elevated CO2 and warming would strongly influence invasive species success in a semi-arid grassland, as a result of both direct and water-mediated indirect effects. To test this hypothesis, we transplanted the invasive forb Linaria dalmatica into mixed-grass prairie treated with free-air CO2 enrichment and infrared warming, and followed survival, growth, and reproduction over 4 yr. We also measured leaf gas exchange and carbon isotopic composition in L. dalmatica and the dominant native C3 grass Pascopyrum smithii. CO2 enrichment increased L. dalmatica biomass 13-fold, seed production 32-fold, and clonal expansion seven-fold, while warming had little effect on L. dalmatica biomass or reproduction. Elevated CO2 decreased stomatal conductance in P. smithii, contributing to higher soil water, but not in L. dalmatica. Elevated CO2 also strongly increased L. dalmatica photosynthesis (87% versus 23% in P. smithii), as a result of both enhanced carbon supply and increased soil water. More broadly, rapid growth and less conservative water use may allow invasive species to take advantage of both carbon fertilization and water savings under elevated CO2 . Water-limited ecosystems may therefore be particularly vulnerable to invasion as CO2 increases. No claim to original US goverment works. New Phytologist © 2013 New Phytologist Trust.

Options to reduce greenhouse gas emissions during wastewater treatment for agricultural use.

PubMed

Fine, Pinchas; Hadas, Efrat

2012-02-01

Treatment of primarily-domestic sewage wastewater involves on-site greenhouse gas (GHG) emissions due to energy inputs, organic matter degradation and biological nutrient removal (BNR). BNR causes both direct emissions and loss of fertilizer value, thus eliminating possible reduction of emissions caused by fertilizer manufacture. In this study, we estimated on-site GHG emissions under different treatment scenarios, and present options for emission reduction by changing treatment methods, avoiding BNR and by recovering energy from biogas. Given a typical Israeli wastewater strength (1050mg CODl(-1)), the direct on-site GHG emissions due to energy use were estimated at 1618 and 2102g CO(2)-eq m(-3), respectively, at intermediate and tertiary treatment levels. A potential reduction of approximately 23-55% in GHG emissions could be achieved by fertilizer preservation and VS conversion to biogas. Wastewater fertilizers constituted a GHG abatement potential of 342g CO(2)-eq m(-3). The residual component that remained in the wastewater effluent following intermediate (oxidation ponds) and enhanced (mechanical-biological) treatments was 304-254g CO(2)-eq m(-3) and 65-34g CO(2)-eq m(-3), respectively. Raw sludge constituted approximately 47% of the overall wastewater fertilizers load with an abatement potential of 150g CO(2)-eq m(-3) (385kg CO(2)-eq dry tonne(-1)). Inasmuch as anaerobic digestion reduced it to 63g CO(2)-eq m(-3) (261kg CO(2)-eq dry tonne(-1)), the GHG abatement gained through renewable biogas energy (approx. 428g CO(2)-eq m(-3)) favored digestion. However, sludge composting reduced the fertilizer value to 17g CO(2)-eq m(-3) (121kg CO(2)-eq dry tonne(-1)) or less (if emissions, off-site inputs and actual phytoavailability were considered). Taking Israel as an example, fully exploiting the wastewater derived GHG abatement potential could reduce the State overall GHG emissions by almost 1%. This demonstrates the possibility of optional carbon credits which might be exploited in the construction of new wastewater treatment facilities, especially in developing countries. Copyright © 2011 Elsevier B.V. All rights reserved.

The impact of geoengineering on vegetation in experiment G1 of the GeoMIP

NASA Astrophysics Data System (ADS)

Glienke, Susanne; Irvine, Peter J.; Lawrence, Mark G.

2015-10-01

Solar Radiation Management (SRM) has been proposed as a mean to partly counteract global warming. The Geoengineering Model Intercomparison Project (GeoMIP) has simulated the climate consequences of a number of SRM techniques. Thus far, the effects on vegetation have not yet been thoroughly analyzed. Here the vegetation response to the idealized GeoMIP G1 experiment from eight fully coupled Earth system models (ESMs) is analyzed, in which a reduction of the solar constant counterbalances the radiative effects of quadrupled atmospheric CO2 concentrations (abrupt4 × CO2). For most models and regions, changes in net primary productivity (NPP) are dominated by the increase in CO2, via the CO2 fertilization effect. As SRM will reduce temperatures relative to abrupt4 × CO2, in high latitudes this will offset increases in NPP. In low latitudes, this cooling relative to the abrupt4 × CO2 simulation decreases plant respiration while having little effect on gross primary productivity, thus increasing NPP. In Central America and the Mediterranean, generally dry regions which are expected to experience increased water stress with global warming, NPP is highest in the G1 experiment for all models due to the easing of water limitations from increased water use efficiency at high-CO2 concentrations and the reduced evaporative demand in a geoengineered climate. The largest differences in the vegetation response are between models with and without a nitrogen cycle, with a much smaller CO2 fertilization effect for the former. These results suggest that until key vegetation processes are integrated into ESM predictions, the vegetation response to SRM will remain highly uncertain.

Modification of fecundity and fertility during oogenesis by. gamma. radiation and/or ozone with a cytological analysis in the ectoparasitic wasp, Habrobracon juglandis (Ashmead)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ofuoku, E.E.

1984-01-01

In Experiment I, adult female wasps were exposed to ozone for 0, 2, 4, 6, 8, 10, 12, 16, 24, and 27 h. The results indicated that the 27 h of ozone exposure produced 100% lethality on the first day. Exposures below 27 h progressively decreased life span with increasing length of exposure. In Experiment II A, adult virgin Habrobracon females were exposed to ozone for 0, 2, 4, 6, 8, 10, 12, 16, and 24 h to determine the effects of ozone on fecundity (egg laying ability) and fertility (egg hatching ability). The results showed that ozone significantly decreasedmore » fecundity and fertility in all meiotic stages except metaphase I. In Experiment II B, adult virgin Habrobracon females were exposed to Co-60 ..gamma.. radiation. All treated wasps showed significant progressive decreases in fecundity and fertility with increases in radiation dose. In Experiment II C, adult virgin Habrobracon females were exposed to Co-60 ..gamma.. radiation, to ozone, or to combinations thereof to determine the effects of these insults on fecundity and fertility. Together or singly ozone and radiation reduced fecundity and fertility. In Experiment III, adult virgin Habrobracon females were exposed to the conditions of Experiment II C to correlate by cytological examination of the ovarioles the effects of ionizing radiation and/or ozone on the germ cells at specific meiotic stages. Results obtained from the cytological study explain the fecundity and fertility observations.« less

Production and turnover of ectomycorrhizal extramatrical mycelial biomass and necromass under elevated CO2 and nitrogen fertilization.

PubMed

Ekblad, Alf; Mikusinska, Anna; Ågren, Göran I; Menichetti, Lorenzo; Wallander, Håkan; Vilgalys, Rytas; Bahr, Adam; Eriksson, Ulrika

2016-08-01

Extramatrical mycelia (EMM) of ectomycorrhizal fungi are important in carbon (C) and nitrogen (N) cycling in forests, but poor knowledge about EMM biomass and necromass turnovers makes the quantification of their role problematic. We studied the impacts of elevated CO2 and N fertilization on EMM production and turnover in a Pinus taeda forest. EMM C was determined by the analysis of ergosterol (biomass), chitin (total bio- and necromass) and total organic C (TOC) of sand-filled mycelium in-growth bags. The production and turnover of EMM bio- and necromass and total C were estimated by modelling. N fertilization reduced the standing EMM biomass C to 57% and its production to 51% of the control (from 238 to 122 kg C ha(-1)  yr(-1) ), whereas elevated CO2 had no detectable effects. Biomass turnover was high (˜13 yr(-1) ) and unchanged by the treatments. Necromass turnover was slow and was reduced from 1.5 yr(-1) in the control to 0.65 yr(-1) in the N-fertilized treatment. However, TOC data did not support an N effect on necromass turnover. An estimated EMM production ranging from 2.5 to 6% of net primary production stresses the importance of its inclusion in C models. A slow EMM necromass turnover indicates an importance in building up forest humus. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Emissions of carbon dioxide and methane from fields fertilized with digestate from an agricultural biogas plant

NASA Astrophysics Data System (ADS)

Czubaszek, Robert; Wysocka-Czubaszek, Agnieszka

2018-01-01

Digestate from biogas plants can play important role in agriculture by providing nutrients, improving soil structure and reducing the use of mineral fertilizers. Still, less is known about greenhouse gas emissions from soil during and after digestate application. The aim of the study was to estimate the emissions of carbon dioxide (CO2) and methane (CH4) from a field which was fertilized with digestate. The gas fluxes were measured with the eddy covariance system. Each day, the eddy covariance system was installed in various places of the field, depending on the dominant wind direction, so that each time the results were obtained from an area where the digestate was distributed. The results showed the relatively low impact of the studied gases emissions on total greenhouse gas emissions from agriculture. Maximum values of the CO2 and CH4 fluxes, 79.62 and 3.049 µmol s-1 m-2, respectively, were observed during digestate spreading on the surface of the field. On the same day, the digestate was mixed with the topsoil layer using a disc harrow. This resulted in increased CO2 emissions the following day. Intense mineralization of digestate, observed after fertilization may not give the expected effects in terms of protection and enrichment of soil organic matter.

Radial growth rate increases in naturally occurring ponderosa pine trees: a late-20th century CO2 fertilization effect?

PubMed

Soulé, Peter T; Knapp, Paul A

2006-01-01

The primary objective of this study was to determine if gradually increasing levels of atmospheric CO2, as opposed to 'step' increases commonly employed in controlled studies, have a positive impact on radial growth rates of ponderosa pine (Pinus ponderosa) in natural environments, and to determine the spatial extent and variability of this growth enhancement. We developed a series of tree-ring chronologies from minimally disturbed sites across a spectrum of environmental conditions. A series of difference of means tests were used to compare radial growth post-1950, when the impacts of rising atmospheric CO2 are best expressed, with that pre-1950. Spearman's correlation was used to relate site stress to growth-rate changes. Significant increases in radial growth rates occurred post-1950, especially during drought years, with the greatest increases generally found at the most water-limited sites. Site harshness is positively related to enhanced radial growth rates. Atmospheric CO2 fertilization is probably operative, having a positive effect on radial growth rates of ponderosa pine through increasing water-use efficiency. A CO2-driven growth enhancement may affect ponderosa pine growing under both natural and controlled conditions.

Atmospheric carbon dioxide, irrigation, and fertilization effects on phenolic and nitrogen concentrations in loblolly pine (Pinus taeda) needles

Treesearch

Fitzgerald L. Booker; Christopher A. Maier

2001-01-01

Concentrations of total soluble phenolics, catechin, proanthocyanidins (PA), lignin and nitrogen (N) were measured in loblolly pine (Pinus taeda L.) needles exposed to either ambient CO2 concentration ([CO2]), ambient plus 175 or ambient plus 350 µmol O2 mol-1 in branch chambers...

Does elevated CO 2 alter silica uptake in trees?

DOE PAGES

Fulweiler, Robinson W.; Maguire, Timothy J.; Carey, Joanna C.; ...

2015-01-13

Human activities have greatly altered global carbon (C) and Nitrogen (N) cycling. In fact, atmospheric concentrations of carbon dioxide (CO 2) have increased 40% over the last century and the amount of N cycling in the biosphere has more than doubled. In an effort to understand how plants will respond to continued global CO 2 fertilization, longterm free-air CO 2 enrichment experiments have been conducted at sites around the globe. Here we examine how atmospheric CO 2 enrichment and N fertilization affects the uptake of silicon (Si) in the Duke Forest, North Carolina, a stand dominated by Pinus taeda (loblollymore » pine), and five hardwood species. Specifically, we measured foliar biogenic silica concentrations in five deciduous and one coniferous species across three treatments: CO 2 enrichment, N enrichment, and N and CO 2 enrichment. We found no consistent trends in foliar Si concentration under elevated CO 2, N fertilization, or combined elevated CO 2 and N fertilization. However, two-thirds of the tree species studied here have Si foliar concentrations greater than well-known Si accumulators, such as grasses. Based on net primary production values and aboveground Si concentrations in these trees, we calculated forest Si uptake rates under control and elevated CO 2 concentrations. Due largely to increased primary production, elevated CO 2 enhanced the magnitude of Si uptake between 20 and 26%, likely intensifying the terrestrial silica pump. This uptake of Si by forests has important implications for Si export from terrestrial systems, with the potential to impact C sequestration and higher trophic levels in downstream ecosystems.« less

A 5-day method for determination of soluble silicon concentrations in nonliquid fertilizer materials using a sodium carbonate-ammonium nitrate extractant followed by visible spectroscopy with heteropoly blue analysis: single-laboratory validation.

PubMed

Sebastian, Dennis; Rodrigues, Hugh; Kinsey, Charles; Korndörfer, Gaspar; Pereira, Hamilton; Buck, Guilherme; Datnoff, Lawrence; Miranda, Stephen; Provance-Bowley, Mary

2013-01-01

A 5-day method for determining the soluble silicon (Si) concentrations in nonliquid fertilizer products was developed using a sodium carbonate (Na2CO3)-ammonium nitrate (NH4NO3) extractant followed by visible spectroscopy with heteropoly blue analysis at 660 nm. The 5-Day Na2CO3-NH4NO3 Soluble Si Extraction Method can be applied to quantify the plant-available Si in solid fertilizer products at levels ranging from 0.2 to 8.4% Si with an LOD of 0.06%, and LOQ of 0.20%. This Si extraction method for fertilizers correlates well with plant uptake of Si (r2 = 0.96 for a range of solid fertilizers) and is applicable to solid Si fertilizer products including blended products and beneficial substances. Fertilizer materials can be processed as received using commercially available laboratory chemicals and materials at ambient laboratory temperatures. The single-laboratory validation of the 5-Day Na2CO3-NH4NO3 Soluble Si Extraction Method has been approved by The Association of American Plant Food Control Officials for testing nonliquid Si fertilizer products.

Influence of Atmospheric CO{sub 2} enrichment on rangeland forage quality and animal grazing. Final technical report, September 1, 1989--August 31, 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sionit, N.

1992-12-31

Increased biomass production in terrestrial ecosystems with elevated atmospheric CO{sub 2}, may be constrained by nutrient limitations as a result of increased requirement or reduced availability caused by reduced turnover rates of nutrients. To determine the short-term impact of nitrogen (N) fertilization on plant biomass production under elevated CO{sub 2}, we compared the response of N-fertilized tallgrass prairie at ambient and twice-ambient CO{sub 2} levels. Native tall grass prairie plots were exposed continuously to ambient and twice-ambient CO{sub 2}. We compared our results to an unfertilized companion experiment on the same research site. Above- and below-ground biomass production and leafmore » area of fertilized plots were greater with elevated than ambient CO{sub 2}. Nitrogen concentration was lower in plants exposed to elevated CO{sub 2}, but total standing crop N was greater at high CO{sub 2} increased root biomass under elevated CO{sub 2} apparently increased N uptake. The biomass production response to elevated CO{sub 2} was much greater on N-fertilized than unfertilized prairie, particularly in the dry year. We conclude that biomass production response to elevated C{sub 2} was suppressed by N limitation in years with below-normal precipitation. Reduced N concentration in above- and below-ground biomass could slow microbial degradation of soil organic matter and surface litter. The reduced tissue N concentration higher acid detergent fiber under elevated CO{sub 2} compared to ambient for forage indicated that ruminant growth and reproduction could be reduced under elevated CO{sub 2}.« less

Using dendrochronology to detect and attribute CO2-induced growth increases in P. menziesii and P. ponderosa in western North America

NASA Astrophysics Data System (ADS)

Stretch, V.; Gedalof, Z.; Berg, A. A.

2010-12-01

Increased atmospheric CO2 could increase photosynthetic rates and cause trees to use water more efficiently, thereby increasing overall growth rates relative to climatic limiting factors. CO2 fertilization has been found across a range of forest types; however results have been inconsistent and based on short-term studies. Long-term studies based on tree-rings have generally been restricted to a few sites and have produced conflicting results. An initial global analysis of tree-ring widths for evidence of increasing growth relative to drought suggested a small but highly significant proportion of trees exhibit increasing growth over the past 130 years. These growth increases could not be attributed to increasing water use efficiency, elevation effects, nitrogen deposition, or divergence. These results suggest that CO2 fertilization is occurring at some locations and may influence future forest dynamics but this does not appear to occur at all locations. The processes causing differential responses are the focus of this study. Here we illustrate response differences between Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa). Using multiple site chronologies from these species over western North America, we demonstrate several site-specific explanations for differential responses to CO2 fertilization, such as forest composition, density, slope, aspect, soil type, and position relative to range limits.

Closing CO2 Loop in Biogas Production: Recycling Ammonia As Fertilizer.

PubMed

He, Qingyao; Yu, Ge; Tu, Te; Yan, Shuiping; Zhang, Yanlin; Zhao, Shuaifei

2017-08-01

We propose and demonstrate a novel system for simultaneous ammonia recovery, carbon capture, biogas upgrading, and fertilizer production in biogas production. Biogas slurry pretreatment (adjusting the solution pH, turbidity, and chemical oxygen demand) plays an important role in the system as it significantly affects the performance of ammonia recovery. Vacuum membrane distillation is used to recover ammonia from biogas slurry at various conditions. The ammonia removal efficiency in vacuum membrane distillation is around 75% regardless of the ammonia concentration of the biogas slurry. The recovered ammonia is used for CO 2 absorption to realize simultaneous biogas upgrading and fertilizer generation. CO 2 absorption performance of the recovered ammonia (absorption capacity and rate) is compared with a conventional model absorbent. Theoretical results on biogas upgrading are also provided. After ammonia recovery, the treated biogas slurry has significantly reduced phytotoxicity, improving the applicability for agricultural irrigation. The novel concept demonstrated in this study shows great potential in closing the CO 2 loop in biogas production by recycling ammonia as an absorbent for CO 2 absorption associated with producing fertilizers.

Water-saving ground cover rice production system reduces net greenhouse gas fluxes in an annual rice-based cropping system

NASA Astrophysics Data System (ADS)

Yao, Z.; Du, Y.; Tao, Y.; Zheng, X.; Liu, C.; Lin, S.; Butterbach-Bahl, K.

2014-11-01

To safeguard food security and preserve precious water resources, the technology of water-saving ground cover rice production system (GCRPS) is being increasingly adopted for rice cultivation. However, changes in soil water status and temperature under GCRPS may affect soil biogeochemical processes that control the biosphere-atmosphere exchanges of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2). The overall goal of this study is to better understand how net ecosystem greenhouse gas exchanges (NEGE) and grain yields are affected by GCRPS in an annual rice-based cropping system. Our evaluation was based on measurements of the CH4 and N2O fluxes and soil heterotrophic respiration (CO2 emissions) over a complete year, and the estimated soil carbon sequestration intensity for six different fertilizer treatments for conventional paddy and GCRPS. The fertilizer treatments included urea application and no N fertilization for both conventional paddy (CUN and CNN) and GCRPS (GUN and GNN), and solely chicken manure (GCM) and combined urea and chicken manure applications (GUM) for GCRPS. Averaging across all the fertilizer treatments, GCRPS increased annual N2O emission and grain yield by 40 and 9%, respectively, and decreased annual CH4 emission by 69%, while GCRPS did not affect soil CO2 emissions relative to the conventional paddy. The annual direct emission factors of N2O were 4.01, 0.09 and 0.50% for GUN, GCM and GUM, respectively, and 1.52% for the conventional paddy (CUN). The annual soil carbon sequestration intensity under GCRPS was estimated to be an average of -1.33 Mg C ha-1 yr-1, which is approximately 44% higher than the conventional paddy. The annual NEGE were 10.80-11.02 Mg CO2-eq ha-1 yr-1 for the conventional paddy and 3.05-9.37 Mg CO2-eq ha-1 yr-1 for the GCRPS, suggesting the potential feasibility of GCRPS in reducing net greenhouse effects from rice cultivation. Using organic fertilizers for GCRPS considerably reduced annual emissions of CH4 and N2O and increased soil carbon sequestration, resulting in the lowest NEGE (3.05-5.00 Mg CO2-eq ha-1 yr-1). Accordingly, water-saving GCRPS with organic fertilizer amendments was considered the most promising management regime for simultaneously achieving relatively high grain yield and reduced net greenhouse gas emission.

Water-saving ground cover rice production system reduces net greenhouse gas fluxes in an annual rice-based cropping system

NASA Astrophysics Data System (ADS)

Yao, Z.; Du, Y.; Tao, Y.; Zheng, X.; Liu, C.; Lin, S.; Butterbach-Bahl, K.

2014-06-01

To safeguard food security and preserve precious water resources, the technology of water-saving ground cover rice production system (GCRPS) is being increasingly adopted for the rice cultivation. However, changes in soil water status and temperature under GCRPS may affect soil biogeochemical processes that control the biosphere-atmosphere exchanges of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2). The overall goal of this study is to better understand how net ecosystem greenhouse gas exchanges (NEGE) and grain yields are affected by GCRPS in an annual rice-based cropping system. Our evaluation was based on measurements of the CH4 and N2O fluxes and soil heterotrophic respiration (CO2 emission) over a complete year, as well as the estimated soil carbon sequestration intensity for six different fertilizer treatments for conventional paddy and GCRPS. The fertilizer treatments included urea application and no N fertilization for both conventional paddy (CUN and CNN) and GCRPS (GUN and GNN), solely chicken manure (GCM) and combined urea and chicken manure applications (GUM) for GCRPS. Averaging across all the fertilizer treatments, GCRPS increased annual N2O emission and grain yield by 40% and 9%, respectively, and decreased annual CH4 emission by 69%, while GCRPS did not affect soil CO2 emissions relative to the conventional paddy. The annual direct emission factors of N2O were 4.01, 0.087 and 0.50% for GUN, GCM and GUM, respectively, and 1.52% for the conventional paddy (CUN). The annual soil carbon sequestration intensity under GCRPS was estimated to be an average of -1.33 Mg C ha-1 yr-1, which is approximately 44% higher than the conventional paddy. The annual NEGE were 10.80-11.02 Mg CO2-eq ha-1 yr-1 for the conventional paddy and 3.05-9.37 Mg CO2-eq ha-1 yr-1 for the GCRPS, suggesting the potential feasibility of GCRPS in reducing net greenhouse effect from rice cultivation. Using organic fertilizers for GCRPS considerably reduced annual emissions of CH4 and N2O and increased soil carbon sequestration, resulting in the lowest NEGE (3.05-5.00 Mg CO2-eq ha-1 yr-1). Accordingly, water-saving GCRPS with organic fertilizer amendments was considered the most promising management regime for simultaneously achieving relatively high grain yield and reduced net greenhouse gas emission.

Land Use Effects on Net Greenhouse Gas Fluxes in the US Great Plains: Historical Trends and Model Projections

NASA Astrophysics Data System (ADS)

Del Grosso, S. J.; Parton, W. J.; Ojima, D. S.; Mosier, A. R.; Mosier, A. R.; Paustian, K.; Peterson, G. A.

2001-12-01

We present maps showing regional patterns of land use change and soil C levels in the US Great Plains during the 20th century and time series of net greenhouse gas fluxes associated with different land uses. Net greenhouse gas fluxes were calculated by accounting for soil CO2 fluxes, the CO2 equivalents of N2O emissions and CH4 uptake, and the CO2 costs of N fertilizer production. Both historical and modern agriculture in this region have been net sources of greenhouse gases. The primary reason for this, prior to 1950, is that agriculture mined soil C and resulted in net CO2 emissions. When chemical N fertilizer became widely used in the 1950's agricultural soils began to sequester CO2-C but these soils were still net greenhouse gas sources if the effects of increased N2O emissions and decreased CH4 uptake are included. The sensitivity of net greenhouse gas fluxes to conventional and alternative land uses was explored using the DAYCENT ecosystem model. Model projections suggest that conversion to no-till, reduction of the fallow period, and use of nitrification inhibitors can significantly decrease net greenhouse gas emissions in dryland and irrigated systems, while maintaining or increasing crop yields.

Efficiency of small scale carbon mitigation by patch iron fertilization

NASA Astrophysics Data System (ADS)

Sarmiento, J. L.; Slater, R. D.; Dunne, J.; Gnanadesikan, A.; Hiscock, M. R.

2010-11-01

While nutrient depletion scenarios have long shown that the high-latitude High Nutrient Low Chlorophyll (HNLC) regions are the most effective for sequestering atmospheric carbon dioxide, recent simulations with prognostic biogeochemical models have suggested that only a fraction of the potential drawdown can be realized. We use a global ocean biogeochemical general circulation model developed at GFDL and Princeton to examine this and related issues. We fertilize two patches in the North and Equatorial Pacific, and two additional patches in the Southern Ocean HNLC region north of the biogeochemical divide and in the Ross Sea south of the biogeochemical divide. We evaluate the simulations using observations from both artificial and natural iron fertilization experiments at nearby locations. We obtain by far the greatest response to iron fertilization at the Ross Sea site, where sea ice prevents escape of sequestered CO2 during the wintertime, and the CO2 removed from the surface ocean by the biological pump is carried into the deep ocean by the circulation. As a consequence, CO2 remains sequestered on century time-scales and the efficiency of fertilization remains almost constant no matter how frequently iron is applied as long as it is confined to the growing season. The second most efficient site is in the Southern Ocean. The North Pacific site has lower initial nutrients and thus a lower efficiency. Fertilization of the Equatorial Pacific leads to an expansion of the suboxic zone and a striking increase in denitrification that causes a sharp reduction in overall surface biological export production and CO2 uptake. The impacts on the oxygen distribution and surface biological export are less prominent at other sites, but nevertheless still a source of concern. The century time scale retention of iron in this model greatly increases the long-term biological response to iron addition as compared with simulations in which the added iron is rapidly scavenged from the ocean.

The influence of microbial-based inoculants on N2O emissions from soil planted with corn (Zea mays L.) under greenhouse conditions with different nitrogen fertilizer regimens.

PubMed

Calvo, Pamela; Watts, Dexter B; Kloepper, Joseph W; Torbert, H Allen

2016-12-01

Nitrous oxide (N 2 O) emissions are increasing at an unprecedented rate owing to the increased use of nitrogen (N) fertilizers. Thus, new innovative management tools are needed to reduce emissions. One potential approach is the use of microbial inoculants in agricultural production. In a previous incubation study, we observed reductions in N 2 O emissions when microbial-based inoculants were added to soil (no plants present) with N fertilizers under laboratory incubations. This present study evaluated the effects of microbial-based inoculants on N 2 O and carbon dioxide (CO 2 ) emissions when applied to soil planted with corn (Zea mays L.) under controlled greenhouse conditions. Inoculant treatments consisted of (i) SoilBuilder (SB), (ii) a metabolite extract of SoilBuilder (SBF), and (iii) a mixture of 4 strains of plant-growth-promoting Bacillus spp. (BM). Experiments included an unfertilized control and 3 N fertilizers: urea, urea - ammonium nitrate with 32% N (UAN-32), and calcium - ammonium nitrate with 17% N (CAN-17). Cumulative N 2 O fluxes from pots 41 days after planting showed significant reductions in N 2 O of 15% (SB), 41% (BM), and 28% (SBF) with CAN-17 fertilizer. When UAN-32 was used, reductions of 34% (SB), 35% (SBF), and 49% (BM) were obtained. However, no reductions in N 2 O emissions occurred with urea. Microbial-based inoculants did not affect total CO 2 emissions from any of the fertilized treatments or the unfertilized control. N uptake was increased by an average of 56% with microbial inoculants compared with the control (nonmicrobial-based treatments). Significant increases in plant height, SPAD chlorophyll readings, and fresh and dry shoot mass were also observed when the microbial-based treatments were applied (with and without N). Overall, results demonstrate that microbial inoculants can reduce N 2 O emissions following fertilizer application depending on the N fertilizer type used and can enhance N uptake and plant growth. Future studies are planned to evaluate the effectiveness of these microbial inoculants in field-based trials and determine the mechanisms involved in N 2 O reduction.

Carbon Dioxide Enrichment: Data on the Response of Cotton to Varying CO2 Irrigation, and Nitrogen (NDP-037)

DOE Data Explorer

Kimball, B. A. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Mauney, J. R. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); La Morte, R. L. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Guinn, G. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Nakayama, F. S. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Radin, J. W. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Lakatos, E. A. [University of Arizona, Tucson, AZ (United States); Mitchell, S. T. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Parker, L. L. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Peresta, G. J. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Nixon III, P. E. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Savoy, B. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Harris, S. M. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); MacDonald, R. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Pros, H. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Martinez, J. [US Dept. of Agriculture (USDA)., Agricultural Research Service, Phoenix, AZ (United States); Sepanski, R. J. [Univ. of Tennessee, Knoxville, TN (United States)

1992-01-01

This NDP presents data on the effects of continuous CO2 enrichment of cotton during five consecutive growing seasons, 1983 to 1987, under both optimal and limiting levels of water and nitrogen. Unlike many prior CO2-enrichment experiments in growth chambers or greenhouses, these studies were conducted on field-planted cotton at close to natural conditions with open-top chambers. Measurements were made on a variety of crop-response variables during the growing season and upon crop harvest. The initial experiment examined the effects of varying CO2 concentration only. During the following two seasons, the interactive effects of CO2 concentration and water availability were studied. During the final two seasons, the interactions among CO2 concentration, water availability, and nitrogen fertility were investigated.

Greenhouse Gas Emissions from Solid and Liquid Organic Fertilizers Applied to Lettuce.

PubMed

Toonsiri, Phasita; Del Grosso, Stephen J; Sukor, Arina; Davis, Jessica G

2016-11-01

Improper application of nitrogen (N) fertilizer and environmental factors can cause the loss of nitrous oxide (NO) to the environment. Different types of fertilizers with different C/N ratios may have different effects on the environment. The focus of this study was to evaluate the effects of environmental factors and four organic fertilizers (feather meal, blood meal, fish emulsion, and cyano-fertilizer) applied at different rates (0, 28, 56, and 112 kg N ha) on NO emissions and to track CO emissions from a lettuce field ( L.). The study was conducted in 2013 and 2014 and compared preplant-applied solid fertilizers (feather meal and blood meal) and multiple applications of liquid fertilizers (fish emulsion and cyano-fertilizer). Three days a week, NO and CO emissions were measured twice per day in 2013 and once per day in 2014 using a closed-static chamber, and gas samples were analyzed by gas chromatography. Preplant-applied solid fertilizers significantly increased cumulative NO emissions as compared with control, but multiple applications of liquid fertilizers did not. Emission factors for NO ranged from 0 to 0.1% for multiple applications of liquid fertilizers and 0.6 to 11% for preplant-applied solid fertilizers, which could be overestimated due to chamber placement over fertilizer bands. In 2014, solid fertilizers with higher C/N ratios (3.3-3.5) resulted in higher CO emissions than liquid fertilizers (C/N ratio, 0.9-1.5). Therefore, organic farmers should consider the use of multiple applications of liquid fertilizers as a means to reduce soil greenhouse gas emissions while maintaining high yields. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Enhancement of non-CO2 radiative forcing via intensified carbon cycle feedbacks

NASA Astrophysics Data System (ADS)

MacDougall, Andrew H.; Knutti, Reto

2016-06-01

The global carbon cycle is sensitive to changes in global temperature and atmospheric CO2 concentration, with increased temperature tending to reduce the efficiency of carbon sinks and increased CO2 enhancing the efficiency of carbon sinks. The emission of non-CO2 greenhouse gases warms the Earth but does not induce the CO2 fertilization effect or increase the partial-pressure gradient between the atmosphere and the surface ocean. Here we present idealized climate model experiments that explore the indirect interaction between non-CO2 forcing and the carbon cycle. The experiments suggest that this interaction enhances the warming effect of the non-CO2 forcing by up to 25% after 150 years and that much of the warming caused by these agents lingers for over 100 years after the dissipation of the non-CO2 forcing. Overall, our results suggest that the longer emissions of non-CO2 forcing agents persists the greater effect these agents will have on global climate.

Soil greenhouse gas emissions affected by irrigation, tillage, crop rotation, and nitrogen fertilization.

PubMed

Sainju, Upendra M; Stevens, William B; Caesar-Tonthat, Thecan; Liebig, Mark A

2012-01-01

Management practices, such as irrigation, tillage, cropping system, and N fertilization, may influence soil greenhouse gas (GHG) emissions. We quantified the effects of irrigation, tillage, crop rotation, and N fertilization on soil CO, NO, and CH emissions from March to November, 2008 to 2011 in a Lihen sandy loam in western North Dakota. Treatments were two irrigation practices (irrigated and nonirrigated) and five cropping systems (conventional-tilled malt barley [ L.] with N fertilizer [CT-N], conventional-tilled malt barley with no N fertilizer [CT-C], no-tilled malt barley-pea [ L.] with N fertilizer [NT-PN], no-tilled malt barley with N fertilizer [NT-N], and no-tilled malt barley with no N fertilizer [NT-C]). The GHG fluxes varied with date of sampling and peaked immediately after precipitation, irrigation, and/or N fertilization events during increased soil temperature. Both CO and NO fluxes were greater in CT-N under the irrigated condition, but CH uptake was greater in NT-PN under the nonirrigated condition than in other treatments. Although tillage and N fertilization increased CO and NO fluxes by 8 to 30%, N fertilization and monocropping reduced CH uptake by 39 to 40%. The NT-PN, regardless of irrigation, might mitigate GHG emissions by reducing CO and NO emissions and increasing CH uptake relative to other treatments. To account for global warming potential for such a practice, information on productions associated with CO emissions along with NO and CH fluxes is needed. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Informing climate models with rapid chamber measurements of forest carbon uptake.

PubMed

Metcalfe, Daniel B; Ricciuto, Daniel; Palmroth, Sari; Campbell, Catherine; Hurry, Vaughan; Mao, Jiafu; Keel, Sonja G; Linder, Sune; Shi, Xiaoying; Näsholm, Torgny; Ohlsson, Klas E A; Blackburn, M; Thornton, Peter E; Oren, Ram

2017-05-01

Models predicting ecosystem carbon dioxide (CO 2 ) exchange under future climate change rely on relatively few real-world tests of their assumptions and outputs. Here, we demonstrate a rapid and cost-effective method to estimate CO 2 exchange from intact vegetation patches under varying atmospheric CO 2 concentrations . We find that net ecosystem CO 2 uptake (NEE) in a boreal forest rose linearly by 4.7 ± 0.2% of the current ambient rate for every 10 ppm CO 2 increase, with no detectable influence of foliar biomass, season, or nitrogen (N) fertilization. The lack of any clear short-term NEE response to fertilization in such an N-limited system is inconsistent with the instantaneous downregulation of photosynthesis formalized in many global models. Incorporating an alternative mechanism with considerable empirical support - diversion of excess carbon to storage compounds - into an existing earth system model brings the model output into closer agreement with our field measurements. A global simulation incorporating this modified model reduces a long-standing mismatch between the modeled and observed seasonal amplitude of atmospheric CO 2 . Wider application of this chamber approach would provide critical data needed to further improve modeled projections of biosphere-atmosphere CO 2 exchange in a changing climate. © 2016 John Wiley & Sons Ltd.

Effect of increased pCO2 level on early shell development in great scallop (Pecten maximus Lamarck) larvae

NASA Astrophysics Data System (ADS)

Andersen, S.; Grefsrud, E. S.; Harboe, T.

2013-10-01

As a result of high anthropogenic CO2 emissions, the concentration of CO2 in the oceans has increased, causing a decrease in pH, known as ocean acidification (OA). Numerous studies have shown negative effects on marine invertebrates, and also that the early life stages are the most sensitive to OA. We studied the effects of OA on embryos and unfed larvae of the great scallop (Pecten maximus Lamarck), at pCO2 levels of 469 (ambient), 807, 1164, and 1599 μatm until seven days after fertilization. To our knowledge, this is the first study on OA effects on larvae of this species. A drop in pCO2 level the first 12 h was observed in the elevated pCO2 groups due to a discontinuation in water flow to avoid escape of embryos. When the flow was restarted, pCO2 level stabilized and was significantly different between all groups. OA affected both survival and shell growth negatively after seven days. Survival was reduced from 45% in the ambient group to 12% in the highest pCO2 group. Shell length and height were reduced by 8 and 15%, respectively, when pCO2 increased from ambient to 1599 μatm. Development of normal hinges was negatively affected by elevated pCO2 levels in both trochophore larvae after two days and veliger larvae after seven days. After seven days, deformities in the shell hinge were more connected to elevated pCO2 levels than deformities in the shell edge. Embryos stained with calcein showed fluorescence in the newly formed shell area, indicating calcification of the shell at the early trochophore stage between one and two days after fertilization. Our results show that P. maximus embryos and early larvae may be negatively affected by elevated pCO2 levels within the range of what is projected towards year 2250, although the initial drop in pCO2 level may have overestimated the effect of the highest pCO2 levels. Future work should focus on long-term effects on this species from hatching, throughout the larval stages, and further into the juvenile and adult stages.

Rapid establishment of the CO2 sink associated with Kerguelen's bloom observed during the KEOPS2/OISO20 cruise

NASA Astrophysics Data System (ADS)

Lo Monaco, C.; Metzl, N.; D'Ovidio, F.; Llort, J.; Ridame, C.

2014-12-01

Iron and light are the main factors limiting the biological pump of CO2 in the Southern Ocean. Iron fertilization experiments have demonstrated the potential for increased uptake of atmospheric CO2, but little is known about the evolution of fertilized environnements. This paper presents observations collected in one of the largest phytoplankton bloom of the Southern Ocean sustained by iron originating from the Kerguelen Plateau. We first complement previous studies by investigating the mechanisms that control air-sea CO2 fluxes over and downstream of the Kerguelen Plateau at the onset of the bloom based on measurements obtained in October-November 2011. These new observations show the rapid establishment of a strong CO2 sink in waters fertilized with iron as soon as vertical mixing is reduced. The magnitude of the CO2 sink was closely related to chlorophyll a and iron concentrations. Because iron concentration strongly depends on the distance from the iron source and the mode of delivery, we identified lateral advection as the main mechanism controlling air-sea CO2 fluxes downtream the Kerguelen Plateau during the growing season. In the southern part of the bloom, situated over the Plateau (iron source), the CO2 sink was stronger and spatially more homogeneous than in the plume offshore. However, we also witnessed a substantial reduction in the uptake of atmospheric CO2 over the Plateau following a strong winds event. Next, we used all the data available in this region in order to draw the seasonal evolution of air-sea CO2 fluxes. The CO2 sink is rapidly reduced during the course of the growing season, which we attribute to iron and silicic acid depletion. South of the Polar Front, where nutrients depletion is delayed, we suggest that the amplitude and duration of the CO2 sink is mainly controlled by vertical mixing. The impact of iron fertilization on air-sea CO2 fluxes is revealed by comparing the uptake of CO2 integrated over the productive season in the bloom, between 1 and 1.5 mol C m-2 yr-1, and in the iron-poor HNLC waters, where we found a typical value of 0.4 mol C m-2 yr-1. Extrapolating our results to the ice-free Southern Ocean (~50-60° S) suggests that iron fertilization of the whole area would increase the contemporay oceanic uptake of CO2 by less than 0.1 Pg C yr-1, i.e., less than 1% of the current anthropogenic CO2 emissions.

N fertilization reduces the losses of old soil organic carbon

NASA Astrophysics Data System (ADS)

Zang, H.; Blagodatskaya, E.; Wang, J.; Kuzyakov, Y.; Xu, X.

2016-12-01

Agricultural soils have experiencing large anthropogenic nitrogen (N) inputs, which directly and indirectly affect soil organic matter (SOM) stocks and CO2 emissions. However, current understanding of how these additional N inputs affect SOM pools of various ages and turnover remains incomplete. The δ13C values of SOM after wheat (C3) - maize (C4) vegetation change enable to calculate the contribution of C4-derived rhizodeposited C (rhizo-C) and C3-derived old SOM pools. Soil (Ap from Haplic Luvisol) sampled from maize rhizosphere was incubated over 56 days after increasing N fertilization (4 levels up to 300 kg N ha-1). N fertilization decreased soil CO2 emissions by 27-42% as compared to unfertilized control. This decrease was mainly caused by the retardation of old C mineralization. The relative availability of rhizo-C (released by maize roots within 4 weeks) for microorganisms was about 10 times higher than of old C (older than 4 weeks). Microbial biomass and dissolved organic C were unaffected by increasing N. N fertilization, however, increased relative contribution of rhizo-C to microbial biomass for 2 - 5 times and to CO2 for about 2 times. This clearly reflects acceleration of microbial biomass turnover by N addition. The decomposition rate of rhizo-C was 3.7 times higher than of old C, and it increased additionally by the factor of 6.5 under high N fertilization. Our study is the first estimated the turnover and incorporation of very recent rhizo-C (within 4 weeks). Compared with several-years old C4, the turnover of rhizo-C was about 2 times faster. Concluding, the contribution of rhizo-C to CO2 and microbial biomass was highly responsive to N fertilization. N fertilization facilitates C sequestration in agricultural soils by decreasing old SOM decomposition mainly through increase the turnover and C use efficiency of rhizo-C. Keywords: CO2 partitioning; C3-C4 vegetation; microbial biomass; SOM decomposition; Nutrient availability

Field experimental data for crop modeling of wheat growth response to nitrogen fertilizer, elevated CO2, water stress, and high temperature

USDA-ARS?s Scientific Manuscript database

Field experimental data of five experiments covering a wide range Field experimental data of five experiments covering a wide range of growing conditions are assembled for wheat growth and cropping systems modeling. The data include (i) an experiment on interactive effects of elevated CO2 by water a...

A Model based Investigation of the Relative Importance of CO2-fertilization, Climate Warming, Nitrogen deposition and Land Use Change on the Global Terrestrial Carbon Cycle in the Historical Period

NASA Astrophysics Data System (ADS)

Bala, G.; N, D.

2015-12-01

In this work, using the fully coupled NCAR Community Earth System Model (CESM1.0.4), we investigate the relative importance of CO2-fertilization, climate warming, anthropogenic nitrogen deposition, and land use and land cover change (LULCC) for terrestrial carbon uptake during the historical period (1850-2005). In our simulations, between the beginning and end of this period, we find an increase in global net primary productivity (NPP) on land of about 4 PgCyr-1 (8.1%) with a contribution of 2.3 PgCyr-1 from CO2-fertilization and 2.0 PgCyr-1 from nitrogen deposition. Climate warming also causes NPP to increase by 0.35 PgCyr-1 but LULCC causes a decline of 0.7 PgCyr-1. These results indicate that the recent increase in vegetation productivity is most likely driven by CO2 fertilization and nitrogen deposition. Further, we find that this configuration of CESM projects that the global terrestrial ecosystem has been a net source of carbon during 1850-2005 (release of 45.1±2.4 PgC), largely driven by historical LULCC related CO2 fluxes to the atmosphere. During the recent three decades (early 1970s to early 2000s), however, our model simulations project that the terrestrial ecosystem acts as a sink, taking up about 10 PgC mainly due to CO2 fertilization and nitrogen deposition. Our results are in good qualitative agreement with recent studies that indicate an increase in vegetation production and water use efficiency in the satellite era and that the terrestrial ecosystem has been a net sink for carbon in recent decades.

Effects of season and nitrogen supply on the partitioning of recently fixed carbon in understory vegetation using a 13CO2 pulse labeling technique

NASA Astrophysics Data System (ADS)

Hasselquist, Niles; Metcalfe, Daniel; Högberg, Peter

2013-04-01

Vegetation research in boreal forests has traditionally been focused on trees, with little attention given to understory vegetation. However, understory vegetation has been identified as a key driver for the functioning of boreal forests and may play an important role in the amount of carbon (C) that is entering and leaving these forested ecosystems. We conducted a large-scale 13C pulse labeling experiment to better understand how recently fixed C is allocated in the understory vegetation characteristic of boreal forests. We used transparent plastic chambers to pulse label the understory vegetation with enriched 13CO2 in the early (June) and late (August) growing seasons. This study was also replicated across a nitrogen (N) fertilization treatment to better understand the effects of N availability on C allocation patterns. We present data on the amount of 13C label found in different components of the understory vegetation (i.e. leaves, stems, lichens, mosses, rhizomes and fine roots) as well as CO2 efflux. Additionally, we provide estimates of C residence time (MRT) among the different components and examine how MRT of C is affected by seasonality and N availability. Seasonality had a large effect on how recently fixed C is allocated in understory vegetation, whereas N fertilization influenced the MRT of C in the different components of ericaceous vegetation. Moreover, there was a general trend that N additions increased the amount of 13C in CO2 efflux compared to the amount of 13C in biomass, suggesting that N fertilization may lead to an increase in the utilization of recently fixed C, whereas N-limitation promotes the storage of recently fixed C.

Effect of long-term fertilization on humic redox mediators in multiple microbial redox reactions.

PubMed

Guo, Peng; Zhang, Chunfang; Wang, Yi; Yu, Xinwei; Zhang, Zhichao; Zhang, Dongdong

2018-03-01

This study investigated the effects of different long-term fertilizations on humic substances (HSs), humic acids (HAs) and humins, functioning as redox mediators for various microbial redox biotransformations, including 2,2',4,4',5,5'- hexachlorobiphenyl (PCB 153 ) dechlorination, dissimilatory iron reduction, and nitrate reduction, and their electron-mediating natures. The redox activity of HSs for various microbial redox metabolisms was substantially enhanced by long-term application of organic fertilizer (pig manure). As a redox mediator, only humin extracted from soils with organic fertilizer amendment (OF-HM) maintained microbial PCB 153 dechlorination activity (1.03 μM PCB 153 removal), and corresponding HA (OF-HA) most effectively enhanced iron reduction and nitrate reduction by Shewanella putrefaciens. Electrochemical analysis confirmed the enhancement of their electron transfer capacity and redox properties. Fourier transform infrared analysis showed that C=C and C=O bonds, and carboxylic or phenolic groups in HSs might be the redox functional groups affected by fertilization. This research enhances our understanding of the influence of anthropogenic fertility on the biogeochemical cycling of elements and in situ remediation ability in agroecosystems through microorganisms' metabolisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of the effects of thermal stress and CO₂-driven acidified seawater on fertilization in coral Acropora digitifera.

PubMed

Iguchi, Akira; Suzuki, Atsushi; Sakai, Kazuhiko; Nojiri, Yukihiro

2015-08-01

Global warming (GW) and ocean acidification (OA) have been recognized as severe threats for reef-building corals that support coral reef ecosystems, but these effects on the early life history stage of corals are relatively unknown compared with the effects on calcification of adult corals. In this study, we evaluated the effects of thermal stress and CO2-driven acidified seawater on fertilization in a reef-building coral, Acropora digitifera. The fertilization rates of A. digitifera decreased in response to thermal stress compared with those under normal seawater conditions. In contrast, the changes of fertilization rates were not evident in the acidified seawater. Generalized Linear Mixed Model (GLMM) predicted that sperm/egg crosses and temperature were explanatory variables in the best-fitted model for the fertilization data. In the best model, interactions between thermal stress and acidified seawater on the fertilization rates were not selected. Our results suggested that coral fertilization is more sensitive to future GW than OA. Taking into consideration the previous finding that sperm motility of A. digitifera was decreased by acidified seawater, the decrease in coral cover followed by that of sperm concentration might cause the interacting effects of GW and OA on coral fertilization.

Bicarbonate uptake by Southern Ocean phytoplankton

NASA Astrophysics Data System (ADS)

Cassar, Nicolas; Laws, Edward A.; Bidigare, Robert R.; Popp, Brian N.

2004-06-01

Marine phytoplankton have the potential to significantly buffer future increases in atmospheric carbon dioxide levels. However, in order for CO2 fertilization to have an effect on carbon sequestration to the deep ocean, the increase in dissolved CO2 must stimulate primary productivity; that is, marine phototrophs must be CO2 limited [, 1993]. Estimation of the extent of bicarbonate (HCO3-) uptake in the oceans is therefore required to determine whether the anthropogenic carbon sources will enhance carbon flux to the deep ocean. Using short-term 14CO2-disequilibrium experiments during the Southern Ocean Iron Experiment (SOFeX), we show that HCO3- uptake by Southern Ocean phytoplankton is significant. Since the majority of dissolved inorganic carbon (DIC) in the ocean is in the form of bicarbonate, the biological pump may therefore be insensitive to anthropogenic CO2. Approximately half of the DIC uptake observed was attributable to direct HCO3- uptake, the other half being direct CO2 uptake mediated either by passive diffusion or active uptake mechanisms. The increase in growth rates and decrease in CO2 concentration associated with the iron fertilization did not trigger any noticeable changes in the mode of DIC acquisition, indicating that under most environmental conditions the carbon concentrating mechanism (CCM) is constitutive. A low-CO2 treatment induced an increase in uptake of CO2, which we attributed to increased extracellular carbonic anhydrase activity, at the expense of direct HCO3- transport across the plasmalemma. Isotopic disequilibrium experimental results are consistent with Southern Ocean carbon stable isotope fractionation data from this and other studies. Although iron fertilization has been shown to significantly enhance phytoplankton growth and may potentially increase carbon flux to the deep ocean, an important source of the inorganic carbon taken up by phytoplankton in this study was HCO3-, whose concentration is negligibly affected by the anthropogenic rise in CO2. We conclude that biological productivity in this region of the world's ocean is unlikely to be directly regulated by natural or anthropogenic variations in atmospheric CO2 concentrations because of the presence of a constitutive CCM.

Exploring a suitable nitrogen fertilizer rate to reduce greenhouse gas emissions and ensure rice yields in paddy fields.

PubMed

Zhong, Yiming; Wang, Xiaopeng; Yang, Jingping; Zhao, Xing; Ye, Xinyi

2016-09-15

The application rate of nitrogen fertilizer was believed to dramatically influence greenhouse gas (GHG) emissions from paddy fields. Thus, providing a suitable nitrogen fertilization rate to ensure rice yields, reducing GHG emissions and exploring emission behavior are important issues for field management. In this paper, a two year experiment with six rates (0, 75, 150, 225, 300, 375kgN/ha) of nitrogen fertilizer application was designed to examine GHG emissions by measuring carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) flux and their cumulative global warming potential (GWP) from paddy fields in Hangzhou, Zhejiang in 2013 and 2014. The results indicated that the GWP and rice yields increased with an increasing application rate of nitrogen fertilizer. Emission peaks of CH4 mainly appeared at the vegetative phase, and emission peaks of CO2, and N2O mainly appeared at reproductive phase of rice growth. The CO2 flux was significantly correlated with soil temperature, while the CH4 flux was influenced by logging water remaining period and N2O flux was significantly associated with nitrogen application rates. This study showed that 225kgN/ha was a suitable nitrogen fertilizer rate to minimize GHG emissions with low yield-scaled emissions of 3.69 (in 2013) and 2.23 (in 2014) kg CO2-eq/kg rice yield as well as to ensure rice yields remained at a relatively high level of 8.89t/ha in paddy fields. Copyright © 2016 Elsevier B.V. All rights reserved.

The fate of Amazonian ecosystems over the coming century arising from changes in climate, atmospheric CO2, and land use.

PubMed

Zhang, Ke; de Almeida Castanho, Andrea D; Galbraith, David R; Moghim, Sanaz; Levine, Naomi M; Bras, Rafael L; Coe, Michael T; Costa, Marcos H; Malhi, Yadvinder; Longo, Marcos; Knox, Ryan G; McKnight, Shawna; Wang, Jingfeng; Moorcroft, Paul R

2015-02-20

There is considerable interest in understanding the fate of the Amazon over the coming century in the face of climate change, rising atmospheric CO 2 levels, ongoing land transformation, and changing fire regimes within the region. In this analysis, we explore the fate of Amazonian ecosystems under the combined impact of these four environmental forcings using three terrestrial biosphere models (ED2, IBIS, and JULES) forced by three bias-corrected IPCC AR4 climate projections (PCM1, CCSM3, and HadCM3) under two land-use change scenarios. We assess the relative roles of climate change, CO 2 fertilization, land-use change, and fire in driving the projected changes in Amazonian biomass and forest extent. Our results indicate that the impacts of climate change are primarily determined by the direction and severity of projected changes in regional precipitation: under the driest climate projection, climate change alone is predicted to reduce Amazonian forest cover by an average of 14%. However, the models predict that CO 2 fertilization will enhance vegetation productivity and alleviate climate-induced increases in plant water stress, and, as a result, sustain high biomass forests, even under the driest climate scenario. Land-use change and climate-driven changes in fire frequency are predicted to cause additional aboveground biomass loss and reductions in forest extent. The relative impact of land use and fire dynamics compared to climate and CO 2 impacts varies considerably, depending on both the climate and land-use scenario, and on the terrestrial biosphere model used, highlighting the importance of improved quantitative understanding of all four factors - climate change, CO 2 fertilization effects, fire, and land use - to the fate of the Amazon over the coming century. © 2015 John Wiley & Sons Ltd.

Effect of Elevated CO2 Concentration, Elevated Temperature and No Nitrogen Fertilization on Methanogenic Archaeal and Methane-Oxidizing Bacterial Community Structures in Paddy Soil

PubMed Central

Liu, Dongyan; Tago, Kanako; Hayatsu, Masahito; Tokida, Takeshi; Sakai, Hidemitsu; Nakamura, Hirofumi; Usui, Yasuhiro; Hasegawa, Toshihiro; Asakawa, Susumu

2016-01-01

Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions. PMID:27600710

Effect of Elevated CO2 Concentration, Elevated Temperature and No Nitrogen Fertilization on Methanogenic Archaeal and Methane-Oxidizing Bacterial Community Structures in Paddy Soil.

PubMed

Liu, Dongyan; Tago, Kanako; Hayatsu, Masahito; Tokida, Takeshi; Sakai, Hidemitsu; Nakamura, Hirofumi; Usui, Yasuhiro; Hasegawa, Toshihiro; Asakawa, Susumu

2016-09-29

Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions.

Effects of CO2 and Nitrogen Fertilization on Growth and Nutrient Content of Juvenile Ponderosa Pine (NDP-061A)

DOE Data Explorer

Johnson, Dale W [Desert Research Inst. (DRI), Reno, NV (United States); University of Nevada, Reno, NV (United States); Ball, J. Timothy [Desert Research Inst. (DRI), Reno, NV (United States); Walker, Roger F [University of Nevada, Reno, NV (United States)

1998-03-01

This data set presents measured values of plant diameter and height, biomass of plant components, and nutrient (carbon, nitrogen, phosphorus, sulfur, potassium, calcium, magnesium, boron, copper, iron, manganese, and zinc) concentrations from a study of the effects of carbon dioxide and nitrogen fertilization on ponderosa pine (Pinus ponderosa Dougl. ex Laws.) conducted in open-top chambers in Placerville, California, from 1991 through 1996. This data set contains values from 1991 through 1993.

The 2017 Fertilizer Emissions Airborne Study (FEAST): Quantifying N2O emissions from croplands and fertilizer plants in the Mississippi River Valley.

NASA Astrophysics Data System (ADS)

Kort, E. A.; Gvakharia, A.; Smith, M. L.; Conley, S.; Frauhammer, K.

2017-12-01

Nitrous Oxide (N2O) is a crucial atmospheric trace gas that drives 21st century stratospheric ozone depletion and substantively impacts climate. Anthropogenic emissions drive the global imbalance and annual growth of N2O, and the dominant anthropogenic source is fertilizer production and application, both of which have large uncertainties. In this presentation we will discuss the FEAST campaign, a study designed to demonstrate new approaches to quantify N2O emissions from fertilizer production and usage with aircraft measurements. In the FEAST campaign we deployed new instrumentation along with experienced flight sensors onboard the Scientific Aviation Mooney aircraft to make 40 hours of continuous 1Hz measurements of N2O, CO2, CO, H2O, CH4, O3, T, and winds. The Mississippi River Valley provided an optimal target as this location includes significant fertilizer production facilities as well as large cropland areas (dominated by corn, soy, rice, and cotton) with substantive fertilizer application. By leveraging our payload and unique airborne capabilities we directly observe and quantify N2O emissions from individual fertilizer production facilities (as well as CO2 and CH4 emissions from these same facilities). We are also able to quantify N2O fluxes from large cropland areas ( 100's km) employing a mass balance approach, a first for N2O, and will show results highlighting differences between crop types and amounts of applied fertilizer. The ability to quantify fluxes of croplands at 100km scale enables new understanding of processes controlling emissions at spatial scales that has eluded prior studies that either rely on extrapolation of small (flux chamber, towers), or work on 1,000+ km spatial scales (regional-global inversions from atmospheric measurements).

Carbonate counter pump stimulated by natural iron fertilization in the Polar Frontal Zone

NASA Astrophysics Data System (ADS)

Salter, Ian; Schiebel, Ralf; Ziveri, Patrizia; Movellan, Aurore; Lampitt, Richard; Wolff, George A.

2014-12-01

The production of organic carbon in the ocean's surface and its subsequent downward export transfers carbon dioxide to the deep ocean. This CO2 drawdown is countered by the biological precipitation of carbonate, followed by sinking of particulate inorganic carbon, which is a source of carbon dioxide to the surface ocean, and hence the atmosphere over 100-1,000 year timescales. The net transfer of CO2 to the deep ocean is therefore dependent on the relative amount of organic and inorganic carbon in sinking particles. In the Southern Ocean, iron fertilization has been shown to increase the export of organic carbon, but it is unclear to what degree this effect is compensated by the export of inorganic carbon. Here we assess the composition of sinking particles collected from sediment traps located in the Polar Frontal Zone of the Southern Ocean. We find that in high-nutrient, low-chlorophyll regions that are characterized by naturally high iron concentrations, fluxes of both organic and inorganic carbon are higher than in regions with no iron fertilization. However, the excess flux of inorganic carbon is greater than that of organic carbon. We estimate that the production and flux of carbonate in naturally iron-fertilized waters reduces the overall amount of CO2 transferred to the deep ocean by 6-32%, compared to 1-4% at the non-fertilized site. We suggest that an increased export of organic carbon, stimulated by iron availability in the glacial sub-Antarctic oceans, may have been accompanied by a strengthened carbonate counter pump.

Biogenic CH4 and N2O emissions overwhelm land CO2 sink in Asia: Toward a full GHG budget

NASA Astrophysics Data System (ADS)

Tian, H.

2017-12-01

The recent global assessment indicates the terrestrial biosphere as a net source of greenhouse gases to the atmosphere (Tian et al Nature 2016). The fluxes of greenhouse gases (GHG) vary by region. Both TD and BU approaches indicate that human-caused biogenic fluxes of CO2, CH4 and N2O in the biosphere of Southern Asia led to a large net climate warming effect, because the 100-year cumulative effects of CH4 and N2O emissions together exceed that of the terrestrial CO2 sink. Southern Asia has about 90% of the global rice fields and represents more than 60% of the world's nitrogen fertilizer consumption, with 64%-81% of CH4 emissions and 36%-52% of N2O emissions derived from the agriculture and waste sectors. Given the large footprint of agriculture in Southern Asia, improved fertilizer use efficiency, rice management and animal diets could substantially reduce global agricultural N2O and CH4 emissions. This study highlights the importance of including all three major GHGs in regional climate impact assessments, mitigation option and climate policy development.

The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump

NASA Astrophysics Data System (ADS)

Jin, X.; Gruber, N.; Frenzel, H.; Doney, S. C.; McWilliams, J. C.

2007-10-01

Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical biogeochemical ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC) removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability) tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump

NASA Astrophysics Data System (ADS)

Jin, X.; Gruber, N.; Frenzel, H.; Doney, S. C.; McWilliams, J. C.

2008-03-01

Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical/biogeochemical/ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC) removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, integrated over 10 years, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production and export. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability) tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

Validation on wheat response to irrigation, CO2 and nitrogen fertilization in the Community Land Model

NASA Astrophysics Data System (ADS)

Lu, Y.

2016-12-01

Wheat is a staple crop for global food security, and is the dominant vegetation cover for a significant fraction of earth's croplands. As such, it plays an important role in soil carbon balance, and land-atmosphere interactions in these key regions. Understanding whether the Community Land Model (CLM) appropriate response to elevated CO2 and different levels of nitrogen fertilization and irrigation is a crucial question. We participated the AgMIP-wheat project and run 72 simulations at Maricopa spring wheat FACE sites and five winter wheat sites in North America forcing with site observed meteorology data. After calibration on the phenology, carbon allocation, and soil hydrology parameters, wheat in CLM45 has reasonable response to irrigation and elevated CO2. However, wheat in CLM45 has no response to low or high N fertilization because the low amount of N fertilization is sufficient for wheat growth in CLM45. We plan to further extend the same simulations for CLM5 (will release in Fall 2016), which has substantial improvements on soil hydrology (improved soil evaporation and plant hydraulic parameterization) and nitrogen dynamics (flexible leaf CN ratio and Vcmax25, plant pays for carbon to get nitrogen). We will evaluate the uncertainties of wheat response to nitrogen fertilization, irrigation, CO2 due to model improvements.

Oleanolic-bioenhancer coloaded chitosan modified nanocarriers attenuate breast cancer cells by multimode mechanism and preserve female fertility.

PubMed

Sharma, Monika; Sharma, Shweta; Sharma, Vikas; Sharma, Komal; Yadav, Santosh Kumar; Dwivedi, Pankaj; Agrawal, Satish; Paliwal, Sarvesh Kumar; Dwivedi, Anil Kumar; Maikhuri, Jagdamba Prasad; Gupta, Gopal; Mishra, Prabhat Ranjan; Rawat, Ajay Kumar Singh

2017-11-01

Addressing multidrug resistant stage of breast cancer is an impediment for chemotherapy. Moreover, breast cancer chemotherapy has potential enduring confrontations i.e. related toxicity including effect on fertility of young female patients. The co-delivery of polyphenolic bio-enhancers with oleanolic acid in chitosan coated PLGA nanoparticles was designed for oral delivery with enhanced antitumor effect consecutively preserving the female fertility. The optimized oleanolic- bio-enhancer nano formulation CH-OA-B-PLGA with particle size was 342.2±3.7nm and zeta potential of 34.2±3.1mV was capable of lowering viability in MDAMB 231 cell line 16 times than OA. Further, mechanistic studies in MDAMB-231 cells revealed that CH-OA-PLGA induces apoptosis by mitochondrial membrane disruption; follows ROS mediated and caspase dependent apoptosis. The antitumor effect studied in 4-T1 induced Balb/c mice mammary tumor model displayed augmented antitumor potency by CH-OA-B-PLGA in comparison to OA. In the in vivo toxicity on Sprague-Dawley rat model, CH-OA-B-PLGA significantly displayed the safe profile and also preserves fertility in female rats. The experiment result suggests co-delivery of oleanolic acid with bio-enhancers as a breakthrough for developing safe chemotherapy for hormone independent breast cancer therapy countering the toxicity issues. Copyright © 2017. Published by Elsevier B.V.

Strategies to improve fertility in post partum Bos indicus cows submitted to a fixed-time insemination protocol with GnRH and PGF2a

USDA-ARS?s Scientific Manuscript database

In Experiment 1, we evaluated the effects of two lengths of progesterone exposure (CIDR; 7 vs. 14 d) prior to a modified CO-Synch protocol, with or without temporary weaning (TW) before GnRH treatments, on fertility of suckled Bos indicus Nelore cows (n = 283) and on calf performance. Timed AI (TAI)...

Modeling cumulative effects in life cycle assessment: the case of fertilizer in wheat production contributing to the global warming potential.

PubMed

Laratte, Bertrand; Guillaume, Bertrand; Kim, Junbeum; Birregah, Babiga

2014-05-15

This paper aims at presenting a dynamic indicator for life cycle assessment (LCA) measuring cumulative impacts over time of greenhouse gas (GHG) emissions from fertilizers used for wheat cultivation and production. Our approach offers a dynamic indicator of global warming potential (GWP), one of the most used indicator of environmental impacts (e.g. in the Kyoto Protocol). For a case study, the wheat production in France was selected and considered by using data from official sources about fertilizer consumption and production of wheat. We propose to assess GWP environmental impact based on LCA method. The system boundary is limited to the fertilizer production for 1 ton of wheat produced (functional unit) from 1910 to 2010. As applied to wheat production in France, traditional LCA shows a maximum GWP impact of 500 kg CO2-eq for 1 ton of wheat production, whereas the GWP impact of wheat production over time with our approach to dynamic LCA and its cumulative effects increases to 18,000 kg CO2-eq for 1 ton of wheat production. In this paper, only one substance and one impact assessment indicator are presented. However, the methodology can be generalized and improved by using different substances and indicators. Copyright © 2014 Elsevier B.V. All rights reserved.

Amplification of heat extremes by plant CO2 physiological forcing.

PubMed

Skinner, Christopher B; Poulsen, Christopher J; Mankin, Justin S

2018-03-15

Plants influence extreme heat events by regulating land-atmosphere water and energy exchanges. The contribution of plants to changes in future heat extremes will depend on the responses of vegetation growth and physiology to the direct and indirect effects of elevated CO 2 . Here we use a suite of earth system models to disentangle the radiative versus vegetation effects of elevated CO 2 on heat wave characteristics. Vegetation responses to a quadrupling of CO 2 increase summer heat wave occurrence by 20 days or more-30-50% of the radiative response alone-across tropical and mid-to-high latitude forests. These increases are caused by CO 2 physiological forcing, which diminishes transpiration and its associated cooling effect, and reduces clouds and precipitation. In contrast to recent suggestions, our results indicate CO 2 -driven vegetation changes enhance future heat wave frequency and intensity in most vegetated regions despite transpiration-driven soil moisture savings and increases in aboveground biomass from CO 2 fertilization.

A comparison of cellulosic fuel yields and separated soil-surface CO2 fluxes in maize and prairie biofuel cropping systems

NASA Astrophysics Data System (ADS)

Nichols, Virginia A.

It has been suggested that strategic incorporation of perennial vegetation into agricultural landscapes could provide ecosystem services while maintaining agricultural productivity. To evaluate potential use of prairie as a Midwestern cellulosic feedstock, we investigated theoretical cellulosic fuel yields, as well as soil-surface carbon dioxide emissions of prairie-based biofuel systems as compared to maize-based systems on fertile soils in Boone County, IA, USA. Investigated systems were: a maize-soybean rotation grown for grain only, continuous maize grown for grain and stover both with and without a winter rye cover crop, and a 31-species reconstructed prairie grown with and without spring nitrogen fertilization for fall-harvested biomass. From 2009-2013, the highest producing system was N-fertilized prairie, averaging 10.4 Mg ha -1 yr-1 above-ground biomass with average harvest removals of 7.8 Mg ha-1 yr-1. The unfertilized prairie produced 7.4 Mg ha-1 yr-1, averaging harvests of 5.3 Mg ha-1 yr-1. Lowest cellulosic biomass harvests were realized from continuous maize systems, averaging 3.5 Mg ha -1 yr-1 when grown with, and 3.7 Mg ha-1 yr-1 when grown without a winter rye cover crop, respectively. Un-fertilized prairie biomass and maize stover had equivalent dietary conversion ratios at 330 g ethanol kg-1 dry biomass, but N-fertilized prairie was lower at 315. Over four years prairie systems averaged 1287 L cellulosic ethanol ha-1 yr-1 more than maize systems, with fertilization increasing prairie ethanol production by 865 L ha-1 yr-1. Harvested biomass accounted for >90% of ethanol yield variation. A major hurdle in carbon cycling studies is the separation of the soil-surface CO2 flux into its respective components. From 2012-2013 we used a shading method to separate soil-surface CO2 resulting from oxidation of soil organic matter and CO2 derived from live-root activity in three systems: unfertilized prairie, N-fertilized prairie, and continuous maize. Contrary to our hypothesis, total growing-season root CO2 flux was not proportional to end-of-season root biomass of cropping systems; unfertilized prairie contained nearly twice the root biomass of N-fertilized prairie, but the two systems' total root CO2 fluxes were not significantly different in either year. We found that the total growing-season flux of both root- and organic matter-derived CO 2 was higher in the prairie systems compared to the maize system. However, on a percentage basis, the prairies' soil-surface CO2 flux from May-September averaged 29% root-derived while from mid-June through September the maize averaged 22% root-derived. The percentage of the total CO2 flux that was root-derived in a given system varied from year to year, indicating there is no set relationship for a given cropping system.

Soil fertility controls soil-atmosphere carbon dioxide and methane fluxes in a tropical landscape converted from lowland forest to rubber and oil palm plantations

NASA Astrophysics Data System (ADS)

Hassler, E.; Corre, M. D.; Tjoa, A.; Damris, M.; Utami, S. R.; Veldkamp, E.

2015-06-01

Expansion of palm oil and rubber production, for which global demand is increasing, causes rapid deforestation in Sumatra, Indonesia and is expected to continue in the next decades. Our study aimed to (1) quantify changes in soil CO2 and CH4 fluxes with land-use change, and (2) determine their controlling factors. In Jambi Province, Sumatra, we selected two landscapes on heavily weathered soils that differ mainly in texture: loam and clay Acrisol soils. At each landscape, we investigated the reference land uses: forest and secondary forest with regenerating rubber, and the converted land uses: rubber (7-17 years old) and oil palm plantations (9-16 years old). We measured soil CO2 and CH4 fluxes monthly from December 2012 to December 2013. Annual soil CO2 fluxes from the reference land uses were correlated with soil fertility: low extractable phosphorus (P) coincided with high annual CO2 fluxes from the loam Acrisol soil that had lower fertility than the clay Acrisol soil (P < 0.05). Soil CO2 fluxes from the oil palm decreased compared to the other land uses (P < 0.01). Across land uses, annual CO2 fluxes were positively correlated with soil organic carbon (C) and negatively correlated with 15N signatures, extractable P and base saturation. This suggests that the reduced soil CO2 fluxes from oil palm was a result of strongly decomposed soil organic matter due to reduced litter input, and possible reduction in C allocation to roots due to improved soil fertility from liming and P fertilization in these plantations. Soil CH4 uptake in the reference land uses was negatively correlated with net nitrogen (N) mineralization and soil mineral N, suggesting N limitation of CH4 uptake, and positively correlated with exchangeable aluminum (Al), indicating decrease in methanotrophic activity at high Al saturation. Reduction in soil CH4 uptake in the converted land uses compared to the reference land uses (P < 0.01) was due to decrease in soil N availability in the converted land uses. Our study shows for the first time that differences in soil fertility control soil-atmosphere exchange of CO2 and CH4 in a tropical landscape, a mechanism that we were able to detect by conducting this study at the landscape scale.

The Fate of Amazonian Ecosystems over the Coming Century Arising from Changes in Climate, Atmospheric CO2 and Land-use

NASA Astrophysics Data System (ADS)

Moorcroft, P. R.; Zhang, K.; Castanho, A. D. D. A.; Galbraith, D.; Moghim, S.; Levine, N. M.; Bras, R. L.; Coe, M. T.; Costa, M. H.; Malhi, Y.; Longo, M.; Knox, R. G.; McKnight, S. L.; Wang, J.

2014-12-01

There is considerable interest and uncertainty regarding the expected fate of the Amazon over the coming century in face of the combined impacts of climate change, rising atmospheric CO2 levels, and on-going land transformation in the region. In this analysis, we explore the fate of Amazonian ecosystems under projected climate, CO2 and land-use change in the 21st century using three state-of-the-art terrestrial biosphere models (ED2, IBIS, and JULES) driven by three representative, bias-corrected GCM climate projections (PCM1, CCSM3, and HadCM3) under the SRES A2 scenario, coupled with two land-use change scenarios. We assess the relative roles of climate change, CO2 fertilization, land-use change, and fire in driving the projected changes in Amazonian biomass and forest extent. Our results indicate that the impacts of climate change depend strongly on the direction and severity of projected changes in precipitation regimes within the region: under the driest climate projection, climate change alone is predicted to reduce Amazonian forest cover by an average of 14%; however, the models predict that CO2 fertilization will enhance vegetation productivity and alleviate climate-induced increases in plant water stress, and as a result sustain high biomass forests, even under the driest climate scenario. Land-use change and changes in fire frequency are predicted cause additional aboveground live biomass loss and changes in forest extent. The relative impact of land-use and fire dynamics versus the impacts of climate and CO2 on the Amazon varies considerably, depending on both the climate and land-use scenarios used and on the terrestrial biosphere model, highlighting the importance of improved understanding of all four factors -- future climate, CO2 fertilization effects, fire and land-use -- to the fate of the Amazon over the coming century.

Mediterranean irrigation under climate change: more efficient irrigation needed to compensate increases in irrigation water requirements

NASA Astrophysics Data System (ADS)

Fader, M.; Shi, S.; von Bloh, W.; Bondeau, A.; Cramer, W.

2015-08-01

Irrigation in the Mediterranean is of vital importance for food security, employment and economic development. This study systematically assesses how climate change and increases in atmospheric CO2 concentrations may affect irrigation requirements in the Mediterranean region by 2080-2090. Future demographic change and technological improvements in irrigation systems are accounted for, as is the spread of climate forcing, warming levels and potential realization of the CO2-fertilization effect. Vegetation growth, phenology, agricultural production and irrigation water requirements and withdrawal were simulated with the process-based ecohydrological and agro-ecosystem model LPJmL after a large development that comprised the improved representation of Mediterranean crops. At present the Mediterranean region could save 35 % of water by implementing more efficient irrigation and conveyance systems. Some countries like Syria, Egypt and Turkey have higher saving potentials than others. Currently some crops, especially sugar cane and agricultural trees, consume in average more irrigation water per hectare than annual crops. Different crops show different magnitude of changes in net irrigation requirements due to climate change, being the increases most pronounced in agricultural trees. The Mediterranean area as a whole might face an increase in gross irrigation requirements between 4 and 18 % from climate change alone if irrigation systems and conveyance are not improved (2 °C global warming combined with full CO2-fertilization effect, and 5 °C global warming combined with no CO2-fertilization effect, respectively). Population growth increases these numbers to 22 and 74 %, respectively, affecting mainly the Southern and Eastern Mediterranean. However, improved irrigation technologies and conveyance systems have large water saving potentials, especially in the Eastern Mediterranean, and may be able to compensate to some degree the increases due to climate change and population growth. Both subregions would need around 35 % more water than today if they could afford some degree of modernization of irrigation and conveyance systems and benefit from the CO2-fertilization effect. Nevertheless, water scarcity might pose further challenges to the agricultural sector: Algeria, Libya, Israel, Jordan, Lebanon, Syria, Serbia, Morocco, Tunisia and Spain have a high risk of not being able to sustainably meet future irrigation water requirements in some scenarios. The results presented in this study point to the necessity of performing further research on climate-friendly agro-ecosystems in order to assess, on the one side, their degree of resilience to climate shocks, and on the other side, their adaptation potential when confronted with higher temperatures and changes in water availability.

Chances and challenges of forest scale CO2 enrichment

NASA Astrophysics Data System (ADS)

Körner, Christian

2016-04-01

Rising CO2 is changing the biosphere's diet. As with any dietary change, both amount and quality of food matter. Atmospheric CO2 enrichment is clearly providing a rather one-sided, C-rich diet. Hence, the reaiistic experimental simulation of its effect on the single biggest C reservoir of the biosphere, that is forest, requires experimental conditions that resemble exactly that situation. In the past, trees where most commonly exposed to elevated CO2 while provided with ample other constituents of a plant's diet (soil nutrients), yielding exaggerated growth stimulation, unlikely to reflect real world responses. So, by either selecting fertile soils, disturbing the system by fire or planting activities, offering ample soil space to isolated individuals or even adding fertilizer, almost any CO2-response can be 'designed'. The 'art' of designing future Free Air CO2 Enrichment (FACE) experiments will be to avoid exactly these pitfalls. Plants can incorporate additional C only to the extent the provision of chemical elements other than C will permit, given the stoichiometry of life. Site selection (soil fertility), degree of canopy closure, recent disturbance regime or successional stage will influence CO2 effects. It is the fundamental dilemma in CO2-enrichment research that simple, homogenous, artificial test systems offer statistical power, while systems that account for 'naturalness' and species diversity do not. Any new FACE program needs to handle that tradeoff between precision and relevance. In this presentation I will advocate a pragmatic approach that will inevitably have to lean on individual tree responses, across a wide as possible range of neighborhoods, age and growth conditions, with the statistical power depending in obtaining the best possible pre-treatment traits and responses. By illustrating the results of 15 years of FACE with 30-40 m tall forest trees, I will caution against over-optimistic ecosystem scale approaches with just ONE technology, given the sheer size such test systems would require. I rather suggest combining the best choice technology at different scales, which is not necessarily the most costly FACE approach. FACE emerged from overestimating potential bias from atmospheric conditions and greatly unerestimating the key role of soil conditions and biodiversity. Reference: Körner C (2006) Plant CO2 responses: an issue of definition, time and resource supply. New Phytol 172:393-411. Bader MKF, et al. (2013) Central European hardwood trees in a high-CO2 future: synthesis of an 8-year forest canopy CO2 enrichment project. J Ecol 101:1509-1519.

Effects of Nitrogen Addition on Litter Decomposition and CO2 Release: Considering Changes in Litter Quantity

PubMed Central

Li, Hui-Chao; Hu, Ya-Lin; Mao, Rong; Zhao, Qiong; Zeng, De-Hui

2015-01-01

This study aims to evaluate the impacts of changes in litter quantity under simulated N deposition on litter decomposition, CO2 release, and soil C loss potential in a larch plantation in Northeast China. We conducted a laboratory incubation experiment using soil and litter collected from control and N addition (100 kg ha−1 year−1 for 10 years) plots. Different quantities of litter (0, 1, 2 and 4 g) were placed on 150 g soils collected from the same plots and incubated in microcosms for 270 days. We found that increased litter input strongly stimulated litter decomposition rate and CO2 release in both control and N fertilization microcosms, though reduced soil microbial biomass C (MBC) and dissolved inorganic N (DIN) concentration. Carbon input (C loss from litter decomposition) and carbon output (the cumulative C loss due to respiration) elevated with increasing litter input in both control and N fertilization microcosms. However, soil C loss potentials (C output–C input) reduced by 62% in control microcosms and 111% in N fertilization microcosms when litter addition increased from 1 g to 4 g, respectively. Our results indicated that increased litter input had a potential to suppress soil organic C loss especially for N addition plots. PMID:26657180

Sperm preparation through Sephadex™ filtration improves in vitro fertilization rate of buffalo oocytes.

PubMed

Husna, A U; Azam, A; Qadeer, S; Awan, M A; Nasreen, S; Shahzad, Q; Fouladi-Nashta, A; Khalid, M; Akhter, S

2018-04-01

Routinely, swim-up method is used to separate high-quality sperm; however, long processing time and close cell-to-cell contact during the centrifugation step are inevitable elements of oxidative stress to sperm. The objective was to evaluate Sephadex ™ and glass wool filtration to separate motile, intact and viable sperm for in vitro fertilization in buffalo. The cumulus-oocyte complexes (COCs) were collected from ovaries of slaughtered buffaloes by aspiration and matured for 24 hr in CO 2 incubator at 38.5°C and 5% CO 2 . Matured COCs were rinsed twice in fertilization TALP and placed in the pre-warmed fertilization medium without sperm. Cryopreserved buffalo semen was thawed at 37°C for 30 s and processed through Sephadex ™ , glass wool filtration and swim-up (control). Total and motile sperm recovery rates were assessed, resuspended in fertilization TALP and incubated for 15-20 min in CO 2 incubator. Samples prepared by each method were divided into two aliquots: one aliquot was studied for sperm quality (progressive motility, membrane integrity, viability, liveability), while the other was subjected to co-incubation with sets of 10-15 in vitro matured oocytes. Data on sperm quality were analysed by ANOVA, while in vitro fertilizing rates were compared by chi-squared test using SPSS-20. Least significant difference (LSD) test was used to compare treatment means. Glass wool filtration yielded higher total and motile sperm recovery rate, while Sephadex ™ filtration improved (p < .05) sperm quality (progressive motility, membrane integrity, viability, liveability). Sperm preparation through Sephadex filtration yielded higher in vitro fertilization rate in terms of cleavage rate compared to glass wool filtration and swim-up (control). In conclusion, cryopreserved Nili-Ravi buffalo sperm selected through Sephadex filtration showed improved quality and yielded better fertilization rates (cleavage rate) of in vitro matured/fertilized oocytes. Sephadex filtration could be a promising technique for use in in vitro fertilization in buffalo. © 2017 Blackwell Verlag GmbH.

Closed-loop 15N measurement of N2O and its isotopomers for real-time greenhouse gas tracing

NASA Astrophysics Data System (ADS)

Slaets, Johanna; Mayr, Leopold; Heiling, Maria; Zaman, Mohammad; Resch, Christian; Weltin, Georg; Gruber, Roman; Dercon, Gerd

2016-04-01

Quantifying sources of nitrous oxide is essential to improve understanding of the global N cycle and to develop climate-smart agriculture, as N2O has a global warming potential 300 times higher than CO2. The isotopic signature and the intramolecular distribution (site preference) of 15N are powerful tools to trace N2O, but the application of these methods is limited as conventional methods cannot provide continuous and in situ data. Here we present a method for closed-loop, real time monitoring of the N2O flux, the isotopic signature and the intramolecular distribution of 15N by using off-axis integrated cavity output spectroscopy (ICOS, Los Gatos Research). The developed method was applied to a fertilizer inhibitor experiment, in which N2O emissions were measured on undisturbed soil cores for three weeks. The treatments consisted of enriched urea-N (100 kg urea-N/ha), the same fertilizer combined with the nitrification inhibitor nitrapyrin (375 g/100 kg urea), and control cores. Monitoring the isotopic signature makes it possible to distinguish emissions from soil and fertilizer. Characterization of site preference could additionally provide a tool to identify different microbial processes leading to N2O emissions. Furthermore, the closed-loop approach enables direct measurement on site and does not require removal of CO2 and H2O. Results showed that 75% of total N2O emissions (total=11 346 μg N2O-N/m2) in the fertilized cores originated from fertilizer, while only 55% of total emissions (total=2 450 μg N2ON/m2) stemmed from fertilizer for the cores treated with nitrapyrin. In the controls, N2O derived from soil was only 40% of the size of the corresponding pool from the fertilized cores, pointing towards a priming effect on the microbial community from the fertilizer and demonstrating the bias that could be introduced by relying on non-treated cores to estimate soil emission rates, rather than using the isotopic signature. The site preference increased linearly over time for the cores with fertilizer and those with nitrapyrin, but the increase was stronger for the fertilized cores: during the first 10 days of the experiment, theses cores showed a more negative site preference than the cores with inhibitor, while during the last 10 days, the site preference for the fertilized cores was more positive than that of the inhibitor. This change indicates that the site preference of 15N can be used to distinguish the processes of nitrification and denitrification, the former having been supressed by nitrapyrin in the cores treated with the inhibitor. Low enrichment levels (5% atomic excess in this study) sufficed in order to separate emissions from soil and fertilizer, making the proposed closed-loop approach a cost-effective and practical tool to obtain a continuous, in situ characterization of N2O sources.

Emissions of nitrous acid (HONO), nitric oxide (NO) and nitrous oxide (N2O) from boreal agricultural soil - Effect of N fertilization

NASA Astrophysics Data System (ADS)

Bhattarai, Hem Raj; Virkajärvi, Perttu; -Yli Pirilä, Pasi; Maljanen, Marja

2017-04-01

There is no doubt that nitrogen (N) fertilization has crucial role in increasing food production. However, in parallel it can cause severe impact in environment such as eutrophication, surface/groundwater pollution via nitrate (NO3-) leaching and emissions of N trace gases. Fertilization increases the emissions of nitrous oxide (N2O) which is 260 stronger greenhouse gas than carbon dioxide (CO2). It also enhances the emissions of nitric oxide (NO); an oxidized and very reactive form of nitrogen which can fluctuate the ozone (O3) concentration in atmosphere and cause acidification. The effects of N- fertilization on the emission of N2O and NO from agricultural soil are well known. However, the effects of N fertilization on nitrous acid (HONO) emissions are unknown. Few studies have shown that HONO is emitted from soil but they lack to interlink fertilization and HONO emission. HONO accounts for 17-34 % of hydroxyl (OH-) radical production? in the atmosphere, OH- radicals have vital role in atmospheric chemistry; they can cause photochemical smog, form O3, oxidize volatile organic compounds and also atmospheric methane (CH4). We formulated hypothesis that N fertilization will increase the HONO emissions as it does for N2O and NO. To study this, we took soil samples from agricultural soil receiving different amount of N-fertilizer (0, 250 and 450 kg ha-1) in eastern Finland. HONO emissions were measured by dynamic chamber technique connected with LOPAP (Quma Elektronik & Analytik GmbH), NO by NOx analyzer (Thermo scientific) and static chamber technique and gas chromatograph was used for N2O gas sampling and analysis. Several soil parameters were also measured to establish the relationship between the soil properties, fertilization rate and HONO emission. This study is important because eventually it will open up more questions regarding the forms of N loss from soils and impact of fertilization on atmospheric chemistry.

Subtask 1.22 - Microbial Cycling of CH4, CO2, and N2O in a Wetlands Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dingyi Ye; Bethany Kurz; Marc Kurz

Soil microbial metabolic activities play an important role in determining CO{sub 2}, CH{sub 4}, and N{sub 2}O fluxes from terrestrial ecosystems. To verify and evaluate CO{sub 2} sequestration potential by wetland restoration in the Prairie Pothole Region (PPR), as well as to address concern over restoration effects on CH{sub 4} and N{sub 2}O emissions, laboratory and in situ microcosm studies on microbial cycling of CO{sub 2}, CH{sub 4}, and N{sub 2}O were initiated. In addition, to evaluate the feasibility of the use of remote sensing to detect soil gas flux from wetlands, a remote-sensing investigation was also conducted. Results ofmore » the laboratory microcosm study unequivocally proved that restoration of PPR wetlands does sequester atmospheric CO{sub 2}. Under the experimental conditions, the simulated restored wetlands did not promote neither N{sub 2}O nor CH{sub 4} fluxes. Application of ammonia enhanced both N{sub 2}O and CH{sub 4} emission, indicating that restoration of PPR wetlands may reduce both N{sub 2}O and CH{sub 4} emission by cutting N-fertilizer input. Enhancement of CO{sub 2} emission by the N-fertilizer was observed, and this observation revealed an overlooked fact that application of N-fertilizer may potentially increase CO{sub 2} emission. In addition, the CO{sub 2} results also demonstrate that wetland restoration sequesters atmospheric carbon not only by turning soil conditions from aerobic to anoxic, but also by cutting N-fertilizer input that may enhance CO{sub 2} flux. The investigation on microbial community structure and population dynamics showed that under the experimental conditions restoration of the PPR wetlands would not dramatically increase population sizes of those microorganisms that produce N{sub 2}O and CH{sub 4}. Results of the in situ study proved that restoration of the PPR wetland significantly reduced CO{sub 2} flux. Ammonia enhanced the greenhouse gas emission and linearly correlated to the CO{sub 2} flux within the experimental rate range (46-200 kg N ha{sup -1}). The results also clarified that the overall reduction in global warming potential (GWP) by the PPR wetland restoration was mainly contributed from reduction in CO{sub 2} flux. These results demonstrate that restoration of currently farmed PPR wetlands will significantly reduce the overall GWP budget. Remote sensing investigations indicate that while the 15-meter resolution of the imagery was sufficient to delineate multiple zones in larger wetlands, it was not sufficient for correlation with the ground-based gas flux measurement data, which were collected primarily for smaller wetland sites (<250 meters) in the areas evaluated by this task. To better evaluate the feasibility of using satellite imagery to quantify wetland gas flux, either higher-resolution satellite imagery or gas flux data from larger wetland sites is needed.« less

The Effects of Nitrogen Fertilization of a Corn Ecosystem's Oxidative Ratio and Its Carbon Cycle Implications

NASA Astrophysics Data System (ADS)

Gallagher, M. E.; Masiello, C. A.; Hockaday, W. C.; McSwiney, C. P.; Robertson, G. P.

2008-12-01

One of the most effective ways to estimate the size of carbon sinks in the terrestrial biosphere and oceans is through paired measurements of atmospheric CO2 and O2 concentrations (e.g. (Keeling et al. 1996)). Successful use of this technique requires knowledge of the oxidative ratio (OR) of the terrestrial biosphere (the ratio of moles of O2 released per moles of CO2 consumed in gas fluxes between the terrestrial biosphere and atmosphere.) Historically the terrestrial biosphere's OR has been assumed to be a constant, approximately 1.1 (e.g. Prentice et al. 2001). However, small shifts in the biosphere's OR values can lead to large variations in the calculated sizes of the terrestrial biosphere and ocean carbon sinks (Randerson et al. 2006). We have recently shown that it is possible to measure the OR of biomass to at least +/- 0.01 units (Masiello et al., 2008), and that there is significant natural variability in ecosystem OR. Ecosystem OR is impacted by human activities. In this presentation, we explore the effects of one major form of anthropogenic ecosystem alteration: nitrogen fertilization. We are measuring ecosystem OR in corn agricultural ecosystems under a range of nitrogen fertilization treatments at the Kellogg Biological Station- Long Term Ecological Research Site (KBS-LTER) in Michigan. We measure OR indirectly, through its relationship with organic carbon oxidation state (Cox) (Masiello et al. 2008). Here we present data showing the effects of varying corn ecosystem nitrogen fertilization rates (from 0 to 202 kg N/ha) on ecosystem OR and the implications it will have on apportionment calculations.

Effects of plant diversity, N fertilization, and elevated carbon dioxide on grassland soil N cycling in a long-term experiment.

PubMed

Mueller, Kevin E; Hobbie, Sarah E; Tilman, David; Reich, Peter B

2013-04-01

The effects of global environmental changes on soil nitrogen (N) pools and fluxes have consequences for ecosystem functions such as plant productivity and N retention. In a 13-year grassland experiment, we evaluated how elevated atmospheric carbon dioxide (CO2 ), N fertilization, and plant species richness alter soil N cycling. We focused on soil inorganic N pools, including ammonium and nitrate, and two N fluxes, net N mineralization and net nitrification. In contrast with existing hypotheses, such as progressive N limitation, and with observations from other, often shorter, studies, elevated CO2 had relatively static and small, or insignificant, effects on soil inorganic N pools and fluxes. Nitrogen fertilization had inconsistent effects on soil N transformations, but increased soil nitrate and ammonium concentrations. Plant species richness had increasingly positive effects on soil N transformations over time, likely because in diverse subplots the concentrations of N in roots increased over time. Species richness also had increasingly positive effects on concentrations of ammonium in soil, perhaps because more carbon accumulated in soils of diverse subplots, providing exchange sites for ammonium. By contrast, subplots planted with 16 species had lower soil nitrate concentrations than less diverse subplots, especially when fertilized, probably due to greater N uptake capacity of subplots with 16 species. Monocultures of different plant functional types had distinct effects on N transformations and nitrate concentrations, such that not all monocultures differed from diverse subplots in the same manner. The first few years of data would not have adequately forecast the effects of N fertilization and diversity on soil N cycling in later years; therefore, the dearth of long-term manipulations of plant species richness and N inputs is a hindrance to forecasting the state of the soil N cycle and ecosystem functions in extant plant communities. © 2012 Blackwell Publishing Ltd.

Sensitivity of Terrestrial Water and Energy Budgets to CO2-Physiological Forcing: An Investigation Using an Offline Land Model

NASA Technical Reports Server (NTRS)

Gopalakrishnan, Ranjith; Bala, Govindsamy; Jayaraman, Mathangi; Cao, Long; Nemani, Ramakrishna; Ravindranath, N. H.

2011-01-01

Increasing concentrations of atmospheric carbon dioxide (CO2) influence climate by suppressing canopy transpiration in addition to its well-known greenhouse gas effect. The decrease in plant transpiration is due to changes in plant physiology (reduced opening of plant stomata). Here, we quantify such changes in water flux for various levels of CO2 concentrations using the National Center for Atmospheric Research s (NCAR) Community Land Model. We find that photosynthesis saturates after 800 ppmv (parts per million, by volume) in this model. However, unlike photosynthesis, canopy transpiration continues to decline at about 5.1% per 100 ppmv increase in CO2 levels. We also find that the associated reduction in latent heat flux is primarily compensated by increased sensible heat flux. The continued decline in canopy transpiration and subsequent increase in sensible heat flux at elevated CO2 levels implies that incremental warming associated with the physiological effect of CO2 will not abate at higher CO2 concentrations, indicating important consequences for the global water and carbon cycles from anthropogenic CO2 emissions. Keywords: CO2-physiological effect, CO2-fertilization, canopy transpiration, water cycle, runoff, climate change 1.

[Effects of long-term applying sulfur- and chloride-containing chemical fertilizers on weed growth in paddy field].

PubMed

Shen, Pu; Gao, Ju-sheng; Xu, Ming-gang; Li, Dong-chu; Niu, De-kui; Qin, Dao-zhu

2011-04-01

An investigation was made at a double-rice paddy field in the Qiyang Red Soil Field Experimental Station, Hunan Province, China to study the species and biomass of weeds growing in rice (Oryza sativa L.) growth season after 34-year application of sulfur (SO4(2-)) and chloride (Cl(-))-containing chemical fertilizers under the same application rates of nitrogen (N), phosphorus (P), and potassium (K). Long-term application of Cl(-)-containing chemical fertilizer resulted in the greatest species number of weeds and the highest biomass of floating weeds and wet weeds, compared with long-term application of SO4(2-) and Cl(-) +SO4(2-)-containing chemical fertilizers. In early rice growth season, the biomass of weeds after applying Cl(-)-containing chemical fertilizer was 51.4% and 17.6% higher than that after applying Cl(-) + SO4(2-) and SO4(2-)-containing chemical fertilizers, respectively; in late rice growth season, the increment was 144% and 242%, respectively. More floating weeds were observed after applying Cl(-) + SO4(2-) and SO4(2-)-containing chemical fertilizers, but few of them were found after applying Cl(-)-containing chemical fertilizer. The total dry mass of weeds and the dry mass of wet weeds were positively correlated with soil Cl(-) content (r = 0.764, P < 0.01 and r = 0.948, P < 0.01, respectively), but negatively correlated with soil SO4(2-)-S content (r = 0.849, P < 0.01 and r = 0.641, P < 0.05). Soil alkali-hydrolyzable N and available P, under the co-effects of soil SO4(2-)-S, Cl(-), and pH, had indirect effects on the total dry mass of weeds. By adopting various fertilization measures to maintain proper soil pH and alkali-hydrolyzable N and available P contents, increase soil SO42(-)-S content, and decrease soil Cl(-) content, it could be possible to effectively inhibit the growth of wet weeds and to decrease the total biomass of weeds in double-rice paddy field.

Probabilistic Change of Wheat Productivity and Water Use in China

NASA Astrophysics Data System (ADS)

Liu, Yujie; Chen, Qiaomin

2017-04-01

Impacts of climate change on agriculture are a major concern worldwide, but uncertainties of climate models and emission scenarios may hamper efforts to adapt to climate change. In this paper, a probabilistic approach is used to estimate the uncertainties and simulate impacts of global warming on wheat production and water use in the main wheat cultivation regions of China, with a global mean temperature (GMT) increase scale relative to 1961-90 values. From output of 20 climate scenarios of the Intergovernmental Panel on Climate Change Data Distribution Centre, median values of projected changes in monthly mean climate variables for representative stations are adapted. These are used to drive the Crop Environment Resource Synthesis (CERES)-Wheat model to simulate wheat production and water use under baseline and global warming scenarios, with and without consideration of carbon dioxide (CO2) fertilization effects. Results show that, because of temperature increase, projected wheat-growing periods for GMT changes of 18, 28, and 38C would shorten, with averaged median values of 3.94%, 6.90%, and 9.67%, respectively. There is a high probability of decreasing (increasing) changes in yield and water-use efficiency under higher temperature scenarios without (with) consideration of CO2 fertilization effects. Elevated CO2 concentration generally compensates for the negative effects of warming temperatures on production. Moreover, positive effects of elevated CO2 concentration on grain yield increase with warming temperatures. The findings could be critical for climate-change-driven agricultural production that ensures global food security.

Reduction of forest floor respiration by fertilization on both carbon dioxide-enriched and reference 17-year-old loblolly pine stands

Treesearch

John R. Butnor; Kurt H. Johnsen; Ram Oren; Gabriel G. Katul

2003-01-01

Elevated atmospheric carbon dioxide (CO2e) increases soil respiration rates in forest, grassland, agricultural and wetland systems as a result of increased growth, root biomass and enhanced biological activity of soil microorganisms. Less is known about how forest floor fluxes respond to the combined effects of elevated CO...

Impacts of elevated CO2 on exogenous Bacillus thuringiensis toxins and transgene expression in transgenic rice under different levels of nitrogen.

PubMed

Jiang, Shoulin; Lu, Yongqing; Dai, Yang; Qian, Lei; Muhammad, Adnan Bodlah; Li, Teng; Wan, Guijun; Parajulee, Megha N; Chen, Fajun

2017-11-07

Recent studies have highlighted great challenges of transgene silencing for transgenic plants facing climate change. In order to understand the impacts of elevated CO 2 on exogenous Bacillus thuringiensis (Bt) toxins and transgene expression in transgenic rice under different levels of N-fertilizer supply, we investigated the biomass, exogenous Bt toxins, Bt-transgene expression and methylation status in Bt rice exposed to two levels of CO 2 concentrations and nitrogen (N) supply (1/8, 1/4, 1/2, 1 and 2 N). It is elucidated that the increased levels of global atmospheric CO 2 concentration will trigger up-regulation of Bt toxin expression in transgenic rice, especially with appropriate increase of N fertilizer supply, while, to some extent, the exogenous Bt-transgene expression is reduced at sub-N levels (1/4 and 1/2N), even though the total protein of plant tissues is reduced and the plant growth is restricted. The unpredictable and stochastic occurrence of transgene silencing and epigenetic alternations remains unresolved for most transgenic plants. It is expected that N fertilization supply may promote the expression of transgenic Bt toxin in transgenic Bt rice, particularly under elevated CO 2 .

Improving farming practices reduces the carbon footprint of spring wheat production.

PubMed

Gan, Yantai; Liang, Chang; Chai, Qiang; Lemke, Reynald L; Campbell, Con A; Zentner, Robert P

2014-11-18

Wheat is one of the world's most favoured food sources, reaching millions of people on a daily basis. However, its production has climatic consequences. Fuel, inorganic fertilizers and pesticides used in wheat production emit greenhouse gases that can contribute negatively to climate change. It is unknown whether adopting alternative farming practices will increase crop yield while reducing carbon emissions. Here we quantify the carbon footprint of alternative wheat production systems suited to semiarid environments. We find that integrating improved farming practices (that is, fertilizing crops based on soil tests, reducing summerfallow frequencies and rotating cereals with grain legumes) lowers wheat carbon footprint effectively, averaging -256 kg CO2 eq ha(-1) per year. For each kg of wheat grain produced, a net 0.027-0.377 kg CO2 eq is sequestered into the soil. With the suite of improved farming practices, wheat takes up more CO2 from the atmosphere than is actually emitted during its production.

Improving farming practices reduces the carbon footprint of spring wheat production

NASA Astrophysics Data System (ADS)

Gan, Yantai; Liang, Chang; Chai, Qiang; Lemke, Reynald L.; Campbell, Con A.; Zentner, Robert P.

2014-11-01

Wheat is one of the world’s most favoured food sources, reaching millions of people on a daily basis. However, its production has climatic consequences. Fuel, inorganic fertilizers and pesticides used in wheat production emit greenhouse gases that can contribute negatively to climate change. It is unknown whether adopting alternative farming practices will increase crop yield while reducing carbon emissions. Here we quantify the carbon footprint of alternative wheat production systems suited to semiarid environments. We find that integrating improved farming practices (that is, fertilizing crops based on soil tests, reducing summerfallow frequencies and rotating cereals with grain legumes) lowers wheat carbon footprint effectively, averaging -256 kg CO2 eq ha-1 per year. For each kg of wheat grain produced, a net 0.027-0.377 kg CO2 eq is sequestered into the soil. With the suite of improved farming practices, wheat takes up more CO2 from the atmosphere than is actually emitted during its production.

Improving farming practices reduces the carbon footprint of spring wheat production

PubMed Central

Gan, Yantai; Liang, Chang; Chai, Qiang; Lemke, Reynald L.; Campbell, Con A.; Zentner, Robert P.

2014-01-01

Wheat is one of the world’s most favoured food sources, reaching millions of people on a daily basis. However, its production has climatic consequences. Fuel, inorganic fertilizers and pesticides used in wheat production emit greenhouse gases that can contribute negatively to climate change. It is unknown whether adopting alternative farming practices will increase crop yield while reducing carbon emissions. Here we quantify the carbon footprint of alternative wheat production systems suited to semiarid environments. We find that integrating improved farming practices (that is, fertilizing crops based on soil tests, reducing summerfallow frequencies and rotating cereals with grain legumes) lowers wheat carbon footprint effectively, averaging −256 kg CO2 eq ha−1 per year. For each kg of wheat grain produced, a net 0.027–0.377 kg CO2 eq is sequestered into the soil. With the suite of improved farming practices, wheat takes up more CO2 from the atmosphere than is actually emitted during its production. PMID:25405548

Risky future for Mediterranean forests unless they undergo extreme carbon fertilization.

PubMed

Gea-Izquierdo, Guillermo; Nicault, Antoine; Battipaglia, Giovanna; Dorado-Liñán, Isabel; Gutiérrez, Emilia; Ribas, Montserrat; Guiot, Joel

2017-07-01

Forest performance is challenged by climate change but higher atmospheric [CO 2 ] (c a ) could help trees mitigate the negative effect of enhanced water stress. Forest projections using data assimilation with mechanistic models are a valuable tool to assess forest performance. Firstly, we used dendrochronological data from 12 Mediterranean tree species (six conifers and six broadleaves) to calibrate a process-based vegetation model at 77 sites. Secondly, we conducted simulations of gross primary production (GPP) and radial growth using an ensemble of climate projections for the period 2010-2100 for the high-emission RCP8.5 and low-emission RCP2.6 scenarios. GPP and growth projections were simulated using climatic data from the two RCPs combined with (i) expected c a ; (ii) constant c a  = 390 ppm, to test a purely climate-driven performance excluding compensation from carbon fertilization. The model accurately mimicked the growth trends since the 1950s when, despite increasing c a , enhanced evaporative demands precluded a global net positive effect on growth. Modeled annual growth and GPP showed similar long-term trends. Under RCP2.6 (i.e., temperatures below +2 °C with respect to preindustrial values), the forests showed resistance to future climate (as expressed by non-negative trends in growth and GPP) except for some coniferous sites. Using exponentially growing c a and climate as from RCP8.5, carbon fertilization overrode the negative effect of the highly constraining climatic conditions under that scenario. This effect was particularly evident above 500 ppm (which is already over +2 °C), which seems unrealistic and likely reflects model miss-performance at high c a above the calibration range. Thus, forest projections under RCP8.5 preventing carbon fertilization displayed very negative forest performance at the regional scale. This suggests that most of western Mediterranean forests would successfully acclimate to the coldest climate change scenario but be vulnerable to a climate warmer than +2 °C unless the trees developed an exaggerated fertilization response to [CO 2 ]. © 2017 John Wiley & Sons Ltd.

Evapotranspiration and water yield of a pine-broadleaf forest are not altered by long-term atmospheric [CO2 ] enrichment under native or enhanced soil fertility.

PubMed

Ward, Eric J; Oren, Ram; Kim, Hyun Seok; Kim, Dohyoung; Tor-Ngern, Pantana; Ewers, Brent E; McCarthy, Heather R; Oishi, A Christopher; Pataki, Diane E; Palmroth, Sari; Phillips, Nathan G; Schäfer, Karina V R

2018-06-27

Changes in evapotranspiration (ET) from terrestrial ecosystems affect their water yield (WY), with considerable ecological and economic consequences. Increases of surface runoff observed over the past century have been attributed to increasing atmospheric CO 2 concentrations resulting in reduced ET by terrestrial ecosystems. Here we evaluate the water balance of a Pinus taeda (L.) forest with a broadleaf component that was exposed to atmospheric [CO 2 ] enrichment (ECO 2 ; +200 ppm) for over 17 years and fertilization for six years, monitored with hundreds of environmental and sap flux sensors on a half-hourly basis. These measurements were synthesized using a 1-dimensional Richard's equation model to evaluate treatment differences in transpiration (T), evaporation (E), ET and WY. We found that ECO 2 did not create significant differences in stand T, ET or WY under either native or enhanced soil fertility, despite a 20% and 13% increase in leaf area index, respectively. While T, ET and WY responded to fertilization, this response was weak (<3% of mean annual precipitation). Likewise, while E responded to ECO 2 in the first 7 years of the study, this effect was of negligible magnitude (<1% mean annual precipitation). Given the global range of conifers similar to P. taeda, our results imply that recent observations of increased global streamflow cannot be attributed to decreases in ET across all ecosystems, demonstrating a great need for model-data synthesis activities to incorporate our current understanding of terrestrial vegetation in global water cycle models. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The secretions of oviduct epithelial cells increase the equine in vitro fertilization rate: are osteopontin, atrial natriuretic peptide A and oviductin involved?

PubMed

Mugnier, Sylvie; Kervella, Morgane; Douet, Cécile; Canepa, Sylvie; Pascal, Géraldine; Deleuze, Stefan; Duchamp, Guy; Monget, Philippe; Goudet, Ghylène

2009-11-19

Oviduct epithelial cells (OEC) co-culture promotes in vitro fertilization (IVF) in human, bovine and porcine species, but no data are available from equine species. Yet, despite numerous attempts, equine IVF rates remain low. Our first aim was to verify a beneficial effect of the OEC on equine IVF. In mammals, oviductal proteins have been shown to interact with gametes and play a role in fertilization. Thus, our second aim was to identify the proteins involved in fertilization in the horse. In the first experiment, we co-incubated fresh equine spermatozoa treated with calcium ionophore and in vitro matured equine oocytes with or without porcine OEC. We showed that the presence of OEC increases the IVF rates. In the subsequent experiments, we co-incubated equine gametes with OEC and we showed that the IVF rates were not significantly different between 1) gametes co-incubated with equine vs porcine OEC, 2) intact cumulus-oocyte complexes vs denuded oocytes, 3) OEC previously stimulated with human Chorionic Gonadotropin, Luteinizing Hormone and/or oestradiol vs non stimulated OEC, 4) in vivo vs in vitro matured oocytes. In order to identify the proteins responsible for the positive effect of OEC, we first searched for the presence of the genes encoding oviductin, osteopontin and atrial natriuretic peptide A (ANP A) in the equine genome. We showed that the genes coding for osteopontin and ANP A are present. But the one for oviductin either has become a pseudogene during evolution of horse genome or has been not well annotated in horse genome sequence. We then showed that osteopontin and ANP A proteins are present in the equine oviduct using a surface plasmon resonance biosensor, and we analyzed their expression during oestrus cycle by Western blot. Finally, we co-incubated equine gametes with or without purified osteopontin or synthesized ANP A. No significant effect of osteopontin or ANP A was observed, though osteopontin slightly increased the IVF rates. Our study shows a beneficial effect of homologous and heterologous oviduct cells on equine IVF rates, though the rates remain low. Furthers studies are necessary to identify the proteins involved. We showed that the surface plasmon resonance technique is efficient and powerful to analyze molecular interactions during fertilization.

The secretions of oviduct epithelial cells increase the equine in vitro fertilization rate: are osteopontin, atrial natriuretic peptide A and oviductin involved?

PubMed Central

2009-01-01

Background Oviduct epithelial cells (OEC) co-culture promotes in vitro fertilization (IVF) in human, bovine and porcine species, but no data are available from equine species. Yet, despite numerous attempts, equine IVF rates remain low. Our first aim was to verify a beneficial effect of the OEC on equine IVF. In mammals, oviductal proteins have been shown to interact with gametes and play a role in fertilization. Thus, our second aim was to identify the proteins involved in fertilization in the horse. Methods & results In the first experiment, we co-incubated fresh equine spermatozoa treated with calcium ionophore and in vitro matured equine oocytes with or without porcine OEC. We showed that the presence of OEC increases the IVF rates. In the subsequent experiments, we co-incubated equine gametes with OEC and we showed that the IVF rates were not significantly different between 1) gametes co-incubated with equine vs porcine OEC, 2) intact cumulus-oocyte complexes vs denuded oocytes, 3) OEC previously stimulated with human Chorionic Gonadotropin, Luteinizing Hormone and/or oestradiol vs non stimulated OEC, 4) in vivo vs in vitro matured oocytes. In order to identify the proteins responsible for the positive effect of OEC, we first searched for the presence of the genes encoding oviductin, osteopontin and atrial natriuretic peptide A (ANP A) in the equine genome. We showed that the genes coding for osteopontin and ANP A are present. But the one for oviductin either has become a pseudogene during evolution of horse genome or has been not well annotated in horse genome sequence. We then showed that osteopontin and ANP A proteins are present in the equine oviduct using a surface plasmon resonance biosensor, and we analyzed their expression during oestrus cycle by Western blot. Finally, we co-incubated equine gametes with or without purified osteopontin or synthesized ANP A. No significant effect of osteopontin or ANP A was observed, though osteopontin slightly increased the IVF rates. Conclusion Our study shows a beneficial effect of homologous and heterologous oviduct cells on equine IVF rates, though the rates remain low. Furthers studies are necessary to identify the proteins involved. We showed that the surface plasmon resonance technique is efficient and powerful to analyze molecular interactions during fertilization. PMID:19925651

[Effects of combined application of nitrogen and phosphorus on diurnal variation of photosynthesis at grain-filling stage and grain yield of super high-yielding wheat].

PubMed

Zhao, Hai-bo; Lin, Qi; Liu, Yi-guo; Jiang, Wen; Liu, Jian-jun; Zhai, Yan-ju

2010-10-01

Taking super high-yielding wheat cultivar Jimai 22 as test material, a field experiment was conducted to study the effects of combined application of nitrogen (N) and phosphorus (P) on the diurnal variation of photosynthesis at grain-filling stage and the grain yield of the cultivar. In treatments CK (without N and P application) and low N/P application (225 kg N x hm(-2) and 75 kg P x hm(-2)), the diurnal variation of net photosynthetic rate (Pn) was presented as double-peak curve, and there existed obvious midday depression of photosynthesis. Under reasonable application of N/P (300 kg N x hm(-2) and 150 kg P x hm(-2), treatment N2P2), the midday depression of photosynthesis weakened or even disappeared. Stomatal and non-stomatal limitations could be the causes of the midday depression. Increasing N and P supply increased the Pn, stomatal conductance (Gs), stomatal limitation value (Ls), and transpiration rate (Tr). Fertilizer P had less effects on the photosynthesis, compared with fertilizer N. When the P supply was over 150 kg x hm(-2), the increment of Pn was alleviated and even decreased. Among the fertilization treatments, treatment N2P2 had the highest Pn, Gs, and water use efficiency, being significantly different from CK. It appeared that fertilizer N had greater regulatory effect on the diurnal variation of photosynthesis, compared with fertilizer P, while the combined application of N and P had significant co-effect on the Pn, Gs, and Tr. A combined application of 300 kg N x hm(-2) and 150 kg P x hm(-2) benefited the enhancement of Pn and grain yield.

Influence of sustainable irrigation regimes and agricultural practices on the soil CO2 fluxes from olive groves in SE Spain

NASA Astrophysics Data System (ADS)

Marañón-Jiménez, Sara; Serrano-Ortíz, Penelope; Vicente-Vicente, Jose Luis; Chamizo, Sonia; Kowalski, Andrew S.

2017-04-01

Olive (Olea europaea) is the dominant agriculture plantation in Spain and its main product, olive oil, is vital to the economy of Mediterranean countries. Given the extensive surface dedicated to olive plantations, olive groves can potentially sequester large amounts of carbon and contribute to mitigate climate change. Their potential for carbon sequestration will, however, largely depend on the management and irrigation practices in the olive grove. Although soil respiration is the main path of C release from the terrestrial ecosystems to the atmosphere and a suitable indicator of soil health and fertility, the interaction of agricultural management practices with irrigation regimes on soil CO2 fluxes have not been assessed yet. Here we investigate the influence of the presence of herbaceous cover, use of artificial fertilizers and their interaction with the irrigation regime on the CO2 emission from the soil to the atmosphere. For this, the three agricultural management treatments were established in replicated plots in an olive grove in the SE of Spain: presence of herbaceous cover ("H"), exclusion of herbaceous cover by using herbicides ("NH"), and exclusion of herbaceous cover along with addition of artificial fertilizers (0.55 kg m-2 year-1 of N, P, K solid fertilizer in the proportion 20:10:10, "NHF"). Within each management treatment, three irrigation regimes were also implemented in a randomized design: no-irrigation ("NO") or rain fed, full irrigation (224 l week-1 per olive tree, "MAX"), and a 50% restriction (112 l week-1 per olive tree, "MED"). Soil respiration was measured every 2-3 weeks at 1, 3, and 5 meters from each olive tree together with soil temperature and soil moisture in order to account for the spatial and seasonal variability over the year. Soil respiration was higher when herbaceous cover was present compared to the herbaceous exclusion, whereas the addition of fertilizer did not exert any significant effect. Although the different irrigation regimes did affect soil moisture, soil CO2 fluxes remained unaffected by the amount of water added. Soil moisture and temperature were actually reduced by the presence of herbaceous cover during the growing season, which suggests water competition between herbaceous plants and olives with counteracting effects on soil respiration values. Soil respiration showed high spatial heterogeneity, with values decreasing exponentially with the distance from the olive trees. These data highlight the need to account for their spatial and seasonal heterogeneity when estimating the contribution of soil respiration to atmospheric CO2 emissions and the crucial role of the agricultural management on determining the carbon sequestration potential of soil from olive groves.

Low temperature circulating fluidized bed gasification and co-gasification of municipal sewage sludge. Part 2: Evaluation of ash materials as phosphorus fertilizer.

PubMed

Thomsen, Tobias Pape; Hauggaard-Nielsen, Henrik; Gøbel, Benny; Stoholm, Peder; Ahrenfeldt, Jesper; Henriksen, Ulrik B; Müller-Stöver, Dorette Sophie

2017-08-01

The study is part 2 of 2 in an investigation of gasification and co-gasification of municipal sewage sludge in low temperature gasifiers. In this work, solid residuals from thermal gasification and co-gasification of municipal sewage sludge were investigated for their potential use as fertilizer. Ashes from five different low temperature circulating fluidized bed (LT-CFB) gasification campaigns including two mono-sludge campaigns, two sludge/straw mixed fuels campaigns and a straw reference campaign were compared. Experiments were conducted on two different LT-CFBs with thermal capacities of 100kW and 6MW, respectively. The assessment included: (i) Elemental composition and recovery of key elements and heavy metals; (ii) content of total carbon (C) and total nitrogen (N); (iii) pH; (iv) water extractability of phosphorus after incubation in soil; and (v) plant phosphorus response measured in a pot experiment with the most promising ash material. Co-gasification of straw and sludge in LT-CFB gasifiers produced ashes with a high content of recalcitrant C, phosphorus (P) and potassium (K), a low content of heavy metals (especially cadmium) and an improved plant P availability compared to the mono-sludge ashes, thereby showing the best fertilizer qualities among all assessed materials. It was also found that bottom ashes from the char reactor contained even less heavy metals than cyclone ashes. It is concluded that LT-CFB gasification and co-gasification is a highly effective way to purify and sanitize sewage sludge for subsequent use in agricultural systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Historical emissions critical for mapping decarbonization pathways

NASA Astrophysics Data System (ADS)

Majkut, J.; Kopp, R. E.; Sarmiento, J. L.; Oppenheimer, M.

2016-12-01

Policymakers have set a goal of limiting temperature increase from human influence on the climate. This motivates the identification of decarbonization pathways to stabilize atmospheric concentrations of CO2. In this context, the future behavior of CO2 sources and sinks define the CO2 emissions necessary to meet warming thresholds with specified probabilities. We adopt a simple model of the atmosphere-land-ocean carbon balance to reflect uncertainty in how natural CO2 sinks will respond to increasing atmospheric CO2 and temperature. Bayesian inversion is used to estimate the probability distributions of selected parameters of the carbon model. Prior probability distributions are chosen to reflect the behavior of CMIP5 models. We then update these prior distributions by running historical simulations of the global carbon cycle and inverting with observationally-based inventories and fluxes of anthropogenic carbon in the ocean and atmosphere. The result is a best-estimate of historical CO2 sources and sinks and a model of how CO2 sources and sinks will vary in the future under various emissions scenarios, with uncertainty. By linking the carbon model to a simple climate model, we calculate emissions pathways and carbon budgets consistent with meeting specific temperature thresholds and identify key factors that contribute to remaining uncertainty. In particular, we show how the assumed history of CO2 emissions from land use change (LUC) critically impacts estimates of the strength of the land CO2 sink via CO2 fertilization. Different estimates of historical LUC emissions taken from the literature lead to significantly different parameterizations of the carbon system. High historical CO2 emissions from LUC lead to a more robust CO2 fertilization effect, significantly lower future atmospheric CO2 concentrations, and an increased amount of CO2 that can be emitted to satisfy temperature stabilization targets. Thus, in our model, historical LUC emissions have a significant impact on allowable carbon budgets under temperture targets.

Exploring the biogeophysical limits of global food production under different climate change scenarios

NASA Astrophysics Data System (ADS)

de Vrese, Philipp; Stacke, Tobias; Hagemann, Stefan

2018-04-01

An adapted Earth system model is used to investigate the limitations that future climate and water availability impose on the potential expansion and productivity of croplands. The model maximizes the cropland area under prevailing climate conditions and accounts for an optimized, sustainable irrigation practice, thus allowing us to consider the two-way feedback between climate and agriculture. For three greenhouse gas concentration scenarios (RCP2.6, RCP4.5, RCP8.5), we show that the total cropland area could be extended substantially throughout the 21st century, especially in South America and sub-Saharan Africa, where the rising water demand resulting from increasing temperatures can largely be met by increasing precipitation and irrigation rates. When accounting for the CO2 fertilization effect, only a few agricultural areas have to be abandoned owing to declines in productivity, while increasing temperatures allow for the expansion of croplands even into high northern latitudes. Without the CO2 fertilization effect there is no increase in the overall cropland fraction during the second half of the century but areal losses in increasingly water-stressed regions can be compensated for by an expansion in regions that were previously too cold. However, global yields are more sensitive and, without the benefits of CO2 fertilization, they may decrease when greenhouse gas concentrations exceed the RCP4.5 scenario. For certain regions the situation is even more concerning and guaranteeing food security in dry areas in Northern Africa, the Middle East and South Asia will become increasingly difficult, even for the idealized scenarios investigated in this study.

Nitrogen fertilization challenges the climate benefit of cellulosic biofuels

DOE PAGES

Ruan, Leilei; Bhardwaj, Ajay K.; Hamilton, Stephen K.; ...

2016-06-01

Cellulosic biofuels are intended to improve future energy and climate security. Nitrogen (N) fertilizer is commonly recommended to stimulate yields but can increase losses of the greenhouse gas nitrous oxide (N 2O) and other forms of reactive N, including nitrate. We measured soil N2O emissions and nitrate leaching along a switchgrass ( Panicum virgatum) high resolution N-fertilizer gradient for three years post-establishment. Results revealed an exponential increase in annual N2O emissions that each year became stronger (R 2 > 0.9, P < 0.001) and deviated further from the fixed percentage assumed for IPCC Tier 1 emission factors. Concomitantly, switchgrass yieldsmore » became less responsive each year to N fertilizer. Nitrate leaching (and calculated indirect N2O emissions) also increased exponentially in response to N inputs, but neither methane (CH4) uptake nor soil organic carbon changed detectably. Overall, N fertilizer inputs at rates greater than crop need curtailed the climate benefit of ethanol production almost two-fold, from a maximum mitigation capacity of–5.71 ± 0.22 Mg CO 2e ha –1 yr –1 in switchgrass fertilized at 56 kgNha –1 to only –2.97 ± 0.18 MgCO 2e ha –1 yr –1 in switchgrass fertilized at 196 kgNha –1. In conclusion, minimizing N fertilizer use will be an important strategy for fully realizing the climate benefits of cellulosic biofuel production.« less

Nitrogen fertilization challenges the climate benefit of cellulosic biofuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruan, Leilei; Bhardwaj, Ajay K.; Hamilton, Stephen K.

Cellulosic biofuels are intended to improve future energy and climate security. Nitrogen (N) fertilizer is commonly recommended to stimulate yields but can increase losses of the greenhouse gas nitrous oxide (N 2O) and other forms of reactive N, including nitrate. We measured soil N2O emissions and nitrate leaching along a switchgrass ( Panicum virgatum) high resolution N-fertilizer gradient for three years post-establishment. Results revealed an exponential increase in annual N2O emissions that each year became stronger (R 2 > 0.9, P < 0.001) and deviated further from the fixed percentage assumed for IPCC Tier 1 emission factors. Concomitantly, switchgrass yieldsmore » became less responsive each year to N fertilizer. Nitrate leaching (and calculated indirect N2O emissions) also increased exponentially in response to N inputs, but neither methane (CH4) uptake nor soil organic carbon changed detectably. Overall, N fertilizer inputs at rates greater than crop need curtailed the climate benefit of ethanol production almost two-fold, from a maximum mitigation capacity of–5.71 ± 0.22 Mg CO 2e ha –1 yr –1 in switchgrass fertilized at 56 kgNha –1 to only –2.97 ± 0.18 MgCO 2e ha –1 yr –1 in switchgrass fertilized at 196 kgNha –1. In conclusion, minimizing N fertilizer use will be an important strategy for fully realizing the climate benefits of cellulosic biofuel production.« less

The Interrelationship of pCO2, Soil Moisture Content, and Biomass Fertilization Expressed in the Carbon Isotope Signature of C3 Plant Tissue

NASA Astrophysics Data System (ADS)

Schubert, B.; Jahren, A. H.

2017-12-01

Hundreds of chamber and field experiments have shown an increase in C3 plant biomass in response to elevated atmospheric carbon dioxide (pCO2); however, secondary water and nutrient deficits are thought to limit this response. Some have hypothesized that secondary limitation might be self-alleviating under elevated pCO2 as greater root biomass imparts enhanced access to water and nutrients. Here we present results of growth chamber experiments designed to test this hypothesis: we grew 206 Arabidopsis thaliana plants within 5 growth chambers, each set at a different level of pCO2: 390, 685, 1075, 1585, and 2175 ppmv. Within each growth chamber, soil moisture content (θm) was maintained across a spectrum: 1.50, 0.83, 0.44, and 0.38 g g-1. After 3 weeks of total growth, tissues were analyzed for both biomass and net carbon isotope discrimination (Δ13C) value. From these values, we calculated Δresidual, which represents the residual effect of water stress after subtraction of the effect of pCO2 due to photorespiration. Across the full range of moisture content, Δresidual displayed a significant 2.5‰ increase with increasing pCO2. This further implies a 0.1 unit increase in ci/ca, consistent with decreased water stress at elevated pCO2. The influence of CO2 fertilization on the alleviation of water stress was further evidenced in a positive correlation between percent biomass change and Δresidual, such that a doubling of plant biomass yielded a 1.85‰ increase in carbon isotope discrimination. In addition to providing new insight into water uptake in plants growing under elevated carbon dioxide, these data underscore the importance of separating the effects of increased pCO2 (via photorespiration) and altered ci/ca (via stomatal conductance) when considering changes in the Δ13C value of C3 land plants during the Anthropocene, or across any geological period that includes a marked change in global carbon cycling.

[Effects of elevated atmospheric CO2 and nitrogen application on cotton biomass, nitrogen utilization and soil urease activity].

PubMed

Lyu, Ning; Yin, Fei-hu; Chen, Yun; Gao, Zhi-jian; Liu, Yu; Shi, Lei

2015-11-01

In this study, a semi-open-top artificial climate chamber was used to study the effect of CO2 enrichment (360 and 540 µmol · mol(-1)) and nitrogen addition (0, 150, 300 and 450 kg · hm(-2)) on cotton dry matter accumulation and distribution, nitrogen absorption and soil urease activity. The results showed that the dry matter accumulation of bud, stem, leaf and the whole plant increased significantly in the higher CO2 concentration treatment irrespective of nitrogen level. The dry matter of all the detected parts of plant with 300 kg · hm(-2) nitrogen addition was significantly higher than those with the other nitrogen levels irrespective of CO2 concentration, indicating reasonable nitrogen fertilization could significantly improve cotton dry matter accumulation. Elevated CO2 concentration had significant impact on the nitrogen absorption contents of cotton bud and stem. Compared to those under CO2 concentration of 360 µmol · mol(-1), the nitrogen contents of bud and stem both increased significantly under CO2 concentration of 540 µmol · mol(-1). The nitrogen content of cotton bud in the treatment of 300 kg · hm(-2) nitrogen was the highest among the four nitrogen fertilizer treatments. While the nitrogen contents of cotton stem in the treatments of 150 kg · hm(-2) and 300 kg · hm(-2) nitrogen levels were higher than those in the treatment of 0 kg · hm(-2) and 450 kg · hm(-2) nitrogen levels. The nitrogen content of cotton leaf was significantly influenced by the in- teraction of CO2 elevation and N addition as the nitrogen content of leaf increased in the treatments of 0, 150 and 300 kg · hm(-2) nitrogen levels under the CO2 concentration of 540 µmol · mol(-1). The nitrogen content in cotton root was significantly increased with the increase of nitrogen fertilizer level under elevated CO2 (540 µmol · mol(-1)) treatment. Overall, the cotton nitrogen absorption content under the elevated CO2 (540 µmol · mol(-1)) treatment was higher than that under the ambient CO2- (360 µmol · mol(-1)) treatment. The order of nitrogen accumulation content in organs was bud > leaf > stem > root. Soil urease activity of both layers increased significantly with the elevation of CO2 concentration in all the nitrogen treatments. Under each CO2 concentration treatment, the soil urease activity in the upper layer (0-20 cm) increased significantly with nitrogen application, while the urease activity under the application of 300 kg · hm(-2) nitrogen was highest in the lower layer (20- 40 cm). The average soil urease activity in the upper layer (0-20 cm) was significantly higher than that in the lower layer (20-40 cm). This study suggested that the cotton dry matter accumulation and nitrogen absorption content were significantly increased in response to the elevated CO2 concentration (540 µmol · mol(-1)) and higher nitrogen addition (300 kg · hm(-2)).

Mediterranean irrigation under climate change: more efficient irrigation needed to compensate for increases in irrigation water requirements

NASA Astrophysics Data System (ADS)

Fader, M.; Shi, S.; von Bloh, W.; Bondeau, A.; Cramer, W.

2016-03-01

Irrigation in the Mediterranean is of vital importance for food security, employment and economic development. This study systematically assesses how climate change and increases in atmospheric CO2 concentrations may affect irrigation requirements in the Mediterranean region by 2080-2090. Future demographic change and technological improvements in irrigation systems are taken into account, as is the spread of climate forcing, warming levels and potential realization of the CO2-fertilization effect. Vegetation growth, phenology, agricultural production and irrigation water requirements and withdrawal were simulated with the process-based ecohydrological and agro-ecosystem model LPJmL (Lund-Potsdam-Jena managed Land) after an extensive development that comprised the improved representation of Mediterranean crops. At present the Mediterranean region could save 35 % of water by implementing more efficient irrigation and conveyance systems. Some countries such as Syria, Egypt and Turkey have a higher savings potential than others. Currently some crops, especially sugar cane and agricultural trees, consume on average more irrigation water per hectare than annual crops. Different crops show different magnitudes of changes in net irrigation requirements due to climate change, the increases being most pronounced in agricultural trees. The Mediterranean area as a whole may face an increase in gross irrigation requirements between 4 and 18 % from climate change alone if irrigation systems and conveyance are not improved (4 and 18 % with 2 °C global warming combined with the full CO2-fertilization effect and 5 °C global warming combined with no CO2-fertilization effect, respectively). Population growth increases these numbers to 22 and 74 %, respectively, affecting mainly the southern and eastern Mediterranean. However, improved irrigation technologies and conveyance systems have a large water saving potential, especially in the eastern Mediterranean, and may be able to compensate to some degree for the increases due to climate change and population growth. Both subregions would need around 35 % more water than today if they implement some degree of modernization of irrigation and conveyance systems and benefit from the CO2-fertilization effect. Nevertheless, water scarcity may pose further challenges to the agricultural sector: Algeria, Libya, Israel, Jordan, Lebanon, Syria, Serbia, Morocco, Tunisia and Spain have a high risk of not being able to sustainably meet future irrigation water requirements in some scenarios. The results presented in this study point to the necessity of performing further research on climate-friendly agro-ecosystems in order to assess, on the one hand, their degree of resilience to climate shocks and, on the other hand, their adaptation potential when confronted with higher temperatures and changes in water availability.

Effect of rising atmospheric carbon dioxide concentration on the protein composition of cereal grain.

PubMed

Wroblewitz, Stefanie; Hüther, Liane; Manderscheid, Remy; Weigel, Hans-Joachim; Wätzig, Hermann; Dänicke, Sven

2014-07-16

The present study investigates effects of rising atmospheric CO2 concentration on protein composition of maize, wheat, and barley grain, especially on the fractions prolamins and glutelins. Cereals were grown at different atmospheric CO2 concentrations to simulate future climate conditions. Influences of two nitrogen fertilization levels were studied for wheat and barley. Enriched CO2 caused an increase of globulin and B-hordein of barley. In maize, the content of globulin, α-zein, and LMW polymers decreased, whereas total glutelin, zein, δ-zein, and HMW polymers rose. Different N supplies resulted in variations of barley subfractions and wheat globulin. Other environmental influences showed effects on the content of nearly all fractions and subfractions. Variations in starch-protein bodies caused by different CO2 treatments could be visualized by scanning electron microscopy. In conclusion, climate change would have impacts on structural composition of proteins and, consequently, on the nutritional value of cereals.

Effects of industrial and agricultural waste amendment on soil greenhouse gas production in a paddy field in Southeastern China

NASA Astrophysics Data System (ADS)

Wang, Weiqi; Neogi, Suvadip; Lai, Derrick Y. F.; Zeng, Congsheng; Wang, Chun; Zeng, Dongping

2017-09-01

Controlling the production and subsequent emissions of greenhouse gases (GHGs) from paddy fields is crucial to minimize the climatic impacts arising from crop production. The application of chemical or biological amendments is one possible way to limit the production of GHGs in paddy soils. Yet, few existing studies have examined the impacts of applying fertilizers originated from industrial and agricultural wastes on soil GHG production and its governing factors in subtropical paddy fields. In this study, we examined the effects of various agricultural and industrial amendments, including biochar, steel slag, shell slag, gypsum slag, and slag-derived silicate and calcium fertilizers, on the production potential of GHGs in an early paddy field in southeast China. The mean CO2 production rates from soils amended with steel slag as well as silicate and calcium fertilizers were significantly higher than those of the controls by 13.4% and 18.6%, respectively (P < 0.05). Mean soil CH4 production rates from the plots amended with steel slag, biochar, shell slag, and gypsum slag were significantly lower than those of the controls by 42.5%, 36.1%, 60.8%, and 61.8%, respectively (P < 0.05). Meanwhile, we found no significant difference in mean soil N2O production rates between the control and any of the treatments (P > 0.05). Overall, the soil production rate of CO2 was positively correlated with that of CH4 (P < 0.05), but negatively correlated with that of N2O (P < 0.05). When compared to the controls, the ratio of soil CO2:CH4 production increased significantly in the plots receiving biochar, and silicate and calcium fertilizer amendments (P < 0.05), while that of CO2:N2O production increased significantly only in the biochar-amended plots. Soil CH4:N2O production ratio decreased significantly in the plots amended with steel slag and gypsum slag, as compared to the controls (P < 0.05). Our results suggest that the application of biochar, shell slag and gypsum slag would help reduce greenhouse gas production and mitigate climate change impacts of rice cultivation, largely attributable to the reduction in methanogenesis.

Nitrogen-Use Efficiency, Nitrous Oxide Emissions, and Cereal Production in Brazil: Current Trends and Forecasts.

PubMed

Pires, Marcel Viana; da Cunha, Dênis Antônio; de Matos Carlos, Sabrina; Costa, Marcos Heil

2015-01-01

The agriculture sector has historically been a major source of greenhouse gas (GHG) emissions into the atmosphere. Although the use of synthetic fertilizers is one of the most common widespread agricultural practices, over-fertilization can lead to negative economic and environmental consequences, such as high production costs, depletion of energy resources, and increased GHG emissions. Here, we provide an analysis to understand the evolution of cereal production and consumption of nitrogen (N) fertilizers in Brazil and to correlate N use efficiency (NUE) with economic and environmental losses as N2O emissions. Our results show that the increased consumption of N fertilizers is associated with a large decrease in NUE in recent years. The CO2 eq. of N2O emissions originating from N fertilization for cereal production were approximately 12 times higher in 2011 than in 1970, indicating that the inefficient use of N fertilizers is directly related to environmental losses. The projected N fertilizer forecasts are 2.09 and 2.37 million ton for 2015 and 2023, respectively. An increase of 0.02% per year in the projected NUE was predicted for the same time period. However, decreases in the projected CO2 eq. emissions for future years were not predicted. In a hypothetical scenario, a 2.39% increase in cereal NUE would lead to $ 21 million savings in N fertilizer costs. Thus, increases in NUE rates would lead not only to agronomic and environmental benefits but also to economic improvement.

Nitrogen-Use Efficiency, Nitrous Oxide Emissions, and Cereal Production in Brazil: Current Trends and Forecasts

PubMed Central

Pires, Marcel Viana; da Cunha, Dênis Antônio; de Matos Carlos, Sabrina; Costa, Marcos Heil

2015-01-01

The agriculture sector has historically been a major source of greenhouse gas (GHG) emissions into the atmosphere. Although the use of synthetic fertilizers is one of the most common widespread agricultural practices, over-fertilization can lead to negative economic and environmental consequences, such as high production costs, depletion of energy resources, and increased GHG emissions. Here, we provide an analysis to understand the evolution of cereal production and consumption of nitrogen (N) fertilizers in Brazil and to correlate N use efficiency (NUE) with economic and environmental losses as N2O emissions. Our results show that the increased consumption of N fertilizers is associated with a large decrease in NUE in recent years. The CO2 eq. of N2O emissions originating from N fertilization for cereal production were approximately 12 times higher in 2011 than in 1970, indicating that the inefficient use of N fertilizers is directly related to environmental losses. The projected N fertilizer forecasts are 2.09 and 2.37 million ton for 2015 and 2023, respectively. An increase of 0.02% per year in the projected NUE was predicted for the same time period. However, decreases in the projected CO2 eq. emissions for future years were not predicted. In a hypothetical scenario, a 2.39% increase in cereal NUE would lead to $ 21 million savings in N fertilizer costs. Thus, increases in NUE rates would lead not only to agronomic and environmental benefits but also to economic improvement. PMID:26252377

Conversion from rice to vegetable production increases N2O emission via increased soil organic matter mineralization.

PubMed

Wu, Lei; Tang, Shuirong; He, Dongdong; Wu, Xian; Shaaban, Muhammad; Wang, Milan; Zhao, Jingsong; Khan, Imran; Zheng, Xunhua; Hu, Ronggui; Horwath, William R

2017-04-01

The conversion from rice to vegetable production widely occurs in China. However, the effects of this conversion on N 2 O emission and the underlying mechanisms are not well understood. In the present study, 12 rice paddies (R) were selected and half of them converted to vegetable fields (V) with the following treatments: rice paddies without N-fertilizer (R-CK), rice paddies with conventional N-fertilizer (R-CN), converted vegetable fields without N-fertilizer (V-CK), and converted vegetable fields with conventional N-fertilizer (V-CN) in a randomized block design with 3 replicates. N 2 O emissions were measured with static chambers from December 2012 to December 2015. Within each V-CN plot, a root exclusion subplot was established to measure soil heterotrophic respiration (CO 2 effluxes), a proxy for soil organic matter mineralization. Conversion of rice paddies to vegetable production dramatically increased N 2 O emissions. The three-year cumulative N 2 O emissions were 0.59, 1.90, 55.50 and 160.14kg N ha -1 for R-CK, R-CN, V-CK and V-CN, respectively. The annual N 2 O emissions from vegetable fields ranged between 5.99 and 113.45kg N ha -1 yr -1 , with substantially higher emissions in the first year. N 2 O fluxes from V-CN were significantly and positively related to CO 2 fluxes and inorganic N concentrations. The linear relationship between natural logarithms of N 2 O and CO 2 fluxes was stronger and the regression coefficient higher in the first year, showing the dependence of N 2 O on soil organic matter mineralization. These results suggest that soil organic matter and N mineralization contributes significantly to N 2 O emission following conversion of rice paddies to vegetable production. Copyright © 2017 Elsevier B.V. All rights reserved.

Ocean acidification affects fish spawning but not paternity at CO2 seeps.

PubMed

Milazzo, Marco; Cattano, Carlo; Alonzo, Suzanne H; Foggo, Andrew; Gristina, Michele; Rodolfo-Metalpa, Riccardo; Sinopoli, Mauro; Spatafora, Davide; Stiver, Kelly A; Hall-Spencer, Jason M

2016-07-27

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse (Symphodus ocellatus) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO2 levels. Despite the higher risk of sperm competition found at elevated CO2, we also found a trend of lower satellite and sneaker male paternity at elevated CO2 Given the importance of fish for food security and ecosystem stability, this study highlights the need for targeted research into the effects of rising CO2 levels on patterns of reproduction in wild fish. © 2016 The Author(s).

Ocean acidification affects fish spawning but not paternity at CO2 seeps

PubMed Central

Cattano, Carlo; Alonzo, Suzanne H.; Foggo, Andrew; Gristina, Michele; Rodolfo-Metalpa, Riccardo; Sinopoli, Mauro; Spatafora, Davide; Stiver, Kelly A.; Hall-Spencer, Jason M.

2016-01-01

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse (Symphodus ocellatus) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO2 levels. Despite the higher risk of sperm competition found at elevated CO2, we also found a trend of lower satellite and sneaker male paternity at elevated CO2. Given the importance of fish for food security and ecosystem stability, this study highlights the need for targeted research into the effects of rising CO2 levels on patterns of reproduction in wild fish. PMID:27466451

Effects of cover crops incorporation and nitrogen fertilization on N2O and CO2 emissions

NASA Astrophysics Data System (ADS)

Kandel, T. P.; Gowda, P. H.; Northup, B. K.; DuPont, J.; Somenahally, A. C.; Rocateli, A.

2017-12-01

In this study, we measured N2O and CO2 fluxes from plots planted to hairy vetch (winter cover crop) and broadleaf vetch (spring cover crop) as N sources for the following crabgrass (summer forage crop) in El Reno, Oklahoma, USA. Comparisons also included 0 and 60 kg ha-1 mineral N fertilizer supplied as dry urea. No significant N2O fluxes were observed during rapid growing periods of cover crops (March-April, 2017), however, large fluxes were observed after hairy vetch incorporation. Immediately after the hairy vetch biomass incorporation, large rainfall events were recorded. The fluxes subsided gradually with drying soil condition but were enhanced after every consecutive rainfall events. A rainfall induced flux measuring up to 8.2 kg N2O ha-1 day-1 was observed after 26 days of biomass incorporation. In total, 29 kg N2O ha-1 (18 kg N ha-1) was emitted within a month after biomass incorporation from hairy vetch plots. Growth of broadleaf vetch was poor and N2O fluxes were also lower. Similarly, plots fertilized with 60 kg N ha-1 had significant fluxes of N2O but the magnitude was much lower than the hairy vetch plots. Dynamics of N2O and CO fluxes correlated strongly. The results thus indicated that although cover crops may provide many environmental/agronomic benefits such as N fixation, soil carbon built-up, weed suppression and erosion control, high N2O emissions may dwarf these benefits.

Plant growth responses to elevated atmospheric CO2 are increased by phosphorus sufficiency but not by arbuscular mycorrhizas.

PubMed

Jakobsen, Iver; Smith, Sally E; Smith, F Andrew; Watts-Williams, Stephanie J; Clausen, Signe S; Grønlund, Mette

2016-11-01

Capturing the full growth potential in crops under future elevated CO 2 (eCO 2 ) concentrations would be facilitated by improved understanding of eCO 2 effects on uptake and use of mineral nutrients. This study investigates interactions of eCO 2 , soil phosphorus (P), and arbuscular mycorrhizal (AM) symbiosis in Medicago truncatula and Brachypodium distachyon grown under the same conditions. The focus was on eCO 2 effects on vegetative growth, efficiency in acquisition and use of P, and expression of phosphate transporter (PT) genes. Growth responses to eCO 2 were positive at P sufficiency, but under low-P conditions they ranged from non-significant in M. truncatula to highly significant in B. distachyon Growth of M. truncatula was increased by AM at low P conditions at both CO 2 levels and eCO 2 ×AM interactions were sparse. Elevated CO 2 had small effects on P acquisition, but enhanced conversion of tissue P into biomass. Expression of PT genes was influenced by eCO 2 , but effects were inconsistent across genes and species. The ability of eCO 2 to partly mitigate P limitation-induced growth reductions in B. distachyon was associated with enhanced P use efficiency, and requirements for P fertilizers may not increase in such species in future CO 2 -rich climates. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Nitrogen Fertilization of Corn: Plant Biochemistry Effects and Carbon Cycle Implications

NASA Astrophysics Data System (ADS)

Gallagher, M. E.; Hockaday, W. C.; Masiello, C. A.; McSwiney, C. P.; Robertson, G. P.; Baldock, J. A.

2008-05-01

Atmospheric carbon dioxide (CO2) concentrations are rising due to anthropogenic CO2 emissions (Alley et al. 2007; Prentice et al. 2001). About half of the anthropogenic CO2 emitted during the 1990s was absorbed by the terrestrial biosphere and ocean (Prentice et al. 2001). It is possible to estimate the size of terrestrial and oceanic carbon sinks individually using atmospheric CO2 and O2 measurements (Keeling et al. 1996). To best estimate the sizes of these carbon sinks, we need to accurately know the oxidative ratio (OR) of the terrestrial biosphere (Randerson et al. 2006). OR is the ratio of the moles of O2 released per moles of CO2 consumed in gas fluxes between the terrestrial biosphere and atmosphere. Though it is likely that the net OR of the biosphere varies with ecosystem type and nutrient status, OR is assumed constant in carbon sink apportionment calculations (e.g. Prentice et al. 2001). Small shifts in OR can lead to large variations in the calculated sizes of the terrestrial biosphere and ocean carbon sinks (Randerson et al. 2006). OR likely shifts with changes in climate, nutrient status, and land use. These shifts are due, in part, to shifts in plant biochemistry. We are measuring ecosystem OR in corn agricultural ecosystems under a range of nitrogen fertilization treatments at the Kellogg Biological Station-Long Term Ecological Research Site (KBS-LTER) in Michigan. We measure OR indirectly, through its relationship with organic carbon oxidation state (Cox) (Masiello et al. in press 2008). Cox can be measured through elemental analysis and, with basic knowledge of plant nitrogen use patterns, Cox values can be converted to OR values. Cox can also be measured through 13C nuclear magnetic resonance spectroscopy (NMR), which can be combined with a molecular mixing model to determine Cox, OR, and plant biochemical composition (i.e. percentage carbohydrates, lignin, lipids, and proteins) (Baldock et al. 2004). Here we present data showing the effects of varying corn ecosystem nitrogen fertilization rates (from 0 to 292 kg N/ha) on ecosystem OR and plant biochemistry.

CO2 induced seawater acidification impacts sea urchin larval development II: gene expression patterns in pluteus larvae.

PubMed

Stumpp, M; Dupont, S; Thorndyke, M C; Melzner, F

2011-11-01

Extensive use of fossil fuels is leading to increasing CO(2) concentrations in the atmosphere and causes changes in the carbonate chemistry of the oceans which represents a major sink for anthropogenic CO(2). As a result, the oceans' surface pH is expected to decrease by ca. 0.4 units by the year 2100, a major change with potentially negative consequences for some marine species. Because of their carbonate skeleton, sea urchins and their larval stages are regarded as likely to be one of the more sensitive taxa. In order to investigate sensitivity of pre-feeding (2 days post-fertilization) and feeding (4 and 7 days post-fertilization) pluteus larvae, we raised Strongylocentrotus purpuratus embryos in control (pH 8.1 and pCO(2) 41 Pa e.g. 399 μatm) and CO(2) acidified seawater with pH of 7.7 (pCO(2) 134 Pa e.g. 1318 μatm) and investigated growth, calcification and survival. At three time points (day 2, day 4 and day 7 post-fertilization), we measured the expression of 26 representative genes important for metabolism, calcification and ion regulation using RT-qPCR. After one week of development, we observed a significant difference in growth. Maximum differences in size were detected at day 4 (ca. 10% reduction in body length). A comparison of gene expression patterns using PCA and ANOSIM clearly distinguished between the different age groups (two-way ANOSIM: Global R=1) while acidification effects were less pronounced (Global R=0.518). Significant differences in gene expression patterns (ANOSIM R=0.938, SIMPER: 4.3% difference) were also detected at day 4 leading to the hypothesis that differences between CO(2) treatments could reflect patterns of expression seen in control experiments of a younger larva and thus a developmental artifact rather than a direct CO(2) effect. We found an up regulation of metabolic genes (between 10%and 20% in ATP-synthase, citrate synthase, pyruvate kinase and thiolase at day 4) and down regulation of calcification related genes (between 23% and 36% in msp130, SM30B, and SM50 at day 4). Ion regulation was mainly impacted by up regulation of Na(+)/K(+)-ATPase at day 4 (15%) and down regulation of NHE3 at day 4 (45%). We conclude that in studies in which a stressor induces an alteration in the speed of development, it is crucial to employ experimental designs with a high time resolution in order to correct for developmental artifacts. This helps prevent misinterpretation of stressor effects on organism physiology. Copyright © 2011 Elsevier Inc. All rights reserved.

Multifunctional slow-release organic-inorganic compound fertilizer.

PubMed

Ni, Boli; Liu, Mingzhu; Lü, Shaoyu; Xie, Lihua; Wang, Yanfang

2010-12-08

Multifunctional slow-release organic-inorganic compound fertilizer (MSOF) has been investigated to improve fertilizer use efficiency and reduce environmental pollution derived from fertilizer overdosage. The special fertilizer is based on natural attapulgite (APT) clay used as a matrix, sodium alginate used as an inner coating and sodium alginate-g-poly(acrylic acid-co-acrylamide)/humic acid (SA-g-P(AA-co-AM)/HA) superabsorbent polymer used as an outer coating. The coated multielement compound fertilizer granules were produced in a pan granulator, and the diameter of the prills was in the range of 2.5-3.5 mm. The structural and chemical characteristics of the product, as well as its efficiency in slowing the nutrients release, were examined. In addition, a mathematical model for nutrient release from the fertilizer was applied to calculate the diffusion coefficient D of nutrients in MSOF. The degradation of the SA-g-P(AA-co-AM)/HA coating was assessed by examining the weight loss with incubation time in soil. It is demonstrated that the product prepared by a simple route with good slow-release property may be expected to have wide potential applications in modern agriculture and horticulture.

Reducing N losses through surface runoff from rice-wheat rotation by improving fertilizer management.

PubMed

Cao, Yansheng; Sun, Huifeng; Liu, Yaqin; Fu, Zishi; Chen, Guifa; Zou, Guoyan; Zhou, Sheng

2017-02-01

To better understand N runoff losses from rice-wheat rotation and demonstrate the effectiveness of improved fertilizer management in reducing N runoff losses, a field study was conducted for three consecutive rice-wheat rotations. Nitrogen losses through surface runoff were measured for five treatments, including CK without N application, C200, C300 simulating the conventional practices, CO200, and CO300. Optimum N rate was applied for C200 and CO200, and 30% of chemical fertilizer was substituted with organic fertilizer for CO200 and CO300 with respect to C200 and C300, respectively. Rice season had higher runoff coefficients than wheat season. Approximately 52% of total N was lost as NH 4 + -N in rice season, ranging from 21 to 83%, and in wheat season, the proportion of NO 3 - -N in total N averaged 53% with a variation from 38 to 67%. The N treatments lost less total N in rice season (1.67-10.7 kg N ha -1 ) than in wheat season (1.72-17.1 kg N ha -1 ). These suggested that a key to controlling N runoff losses from rice-wheat rotation was to limit NO 3 - -N accumulation in wheat season. In both seasons, N runoff losses for C200 and CO300 were lower than those for C300. CO200 better cut N losses than C200 and CO300, with 64 and 57% less N in rice and wheat seasons than C300, respectively. Compared with the conventional practices, optimum N inputs integrated with co-application of organic and chemical fertilizers could reduce N runoff losses with a better N balance under rice-wheat rotation.

Effects of Land-Use Conversion from Double Rice Cropping to Vegetables on Methane and Nitrous Oxide Fluxes in Southern China

PubMed Central

Yuan, Ye; Dai, Xiaoqin; Wang, Huimin; Xu, Ming; Fu, Xiaoli; Yang, Fengting

2016-01-01

Compared with CO2, methane (CH4) and nitrous oxide (N2O) are potent greenhouse gases in terms of their global warming potentials. Previous studies have indicated that land-use conversion has a significant impact on greenhouse gas emissions. However, little is known regarding the impact of converting rice (Oryza sativa L.) to vegetable fields, an increasing trend in land-use change in southern China, on CH4 and N2O fluxes. The effects of converting double rice cropping to vegetables on CH4 and N2O fluxes were examined using a static chamber method in southern China from July 2012 to July 2013. The results indicate that CH4 fluxes could reach 31.6 mg C m−2 h−1 under rice before land conversion. The cumulative CH4 emissions for fertilized and unfertilized rice were 348.9 and 321.0 kg C ha−1 yr−1, respectively. After the land conversion, the cumulative CH4 emissions were −0.4 and 1.4 kg C ha−1 yr−1 for the fertilized and unfertilized vegetable fields, respectively. Similarly, the cumulative N2O fluxes under rice were 1.27 and 0.56 kg N ha−1 yr−1 for the fertilized and unfertilized treatments before the land conversion and 19.2 and 8.5 kg N ha−1 yr−1, respectively, after the land conversion. By combining the global warming potentials (GWPs) of both gases, the overall land-use conversion effect was minor (P = 0.36) with fertilization, but the conversion reduced GWP by 63% when rice and vegetables were not fertilized. Increase in CH4 emissions increased GWP under rice compared with vegetables with non-fertilization, but increased N2O emissions compensated for similar GWPs with fertilization under rice and vegetables. PMID:27195497

Effects of Land-Use Conversion from Double Rice Cropping to Vegetables on Methane and Nitrous Oxide Fluxes in Southern China.

PubMed

Yuan, Ye; Dai, Xiaoqin; Wang, Huimin; Xu, Ming; Fu, Xiaoli; Yang, Fengting

2016-01-01

Compared with CO2, methane (CH4) and nitrous oxide (N2O) are potent greenhouse gases in terms of their global warming potentials. Previous studies have indicated that land-use conversion has a significant impact on greenhouse gas emissions. However, little is known regarding the impact of converting rice (Oryza sativa L.) to vegetable fields, an increasing trend in land-use change in southern China, on CH4 and N2O fluxes. The effects of converting double rice cropping to vegetables on CH4 and N2O fluxes were examined using a static chamber method in southern China from July 2012 to July 2013. The results indicate that CH4 fluxes could reach 31.6 mg C m-2 h-1 under rice before land conversion. The cumulative CH4 emissions for fertilized and unfertilized rice were 348.9 and 321.0 kg C ha-1 yr-1, respectively. After the land conversion, the cumulative CH4 emissions were -0.4 and 1.4 kg C ha-1 yr-1 for the fertilized and unfertilized vegetable fields, respectively. Similarly, the cumulative N2O fluxes under rice were 1.27 and 0.56 kg N ha-1 yr-1 for the fertilized and unfertilized treatments before the land conversion and 19.2 and 8.5 kg N ha-1 yr-1, respectively, after the land conversion. By combining the global warming potentials (GWPs) of both gases, the overall land-use conversion effect was minor (P = 0.36) with fertilization, but the conversion reduced GWP by 63% when rice and vegetables were not fertilized. Increase in CH4 emissions increased GWP under rice compared with vegetables with non-fertilization, but increased N2O emissions compensated for similar GWPs with fertilization under rice and vegetables.

Spatial variation related to hydroloigc patterns and vegetation in greenhouse gas fluxes from the Mississippi Delta agricultural region

USDA-ARS?s Scientific Manuscript database

Methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) fluxes from agricultural landscapes may contribute significantly to regional greenhouse gas budgets due to stimulation of soil microbial activity through fertilizer application and variable soil moisture effects. In this study, measuremen...

Genotypic effects of elevated CO[sub 2] on fecundity in an annual weed (wild radish, Raphanus raphanistrum)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, P.S.; Snow, A.A.

1993-06-01

Rising atmospheric CO[sub 2] levels may lead to microevolutionary change in native plant populations. To test for within-population variation in genetic responses to elevated p(CO[sub 2]), we exposed five paternal sibships of wild radish to ambient and 2X ambient (700 [mu]bar) p(CO[sub 2]) in 3 m open top chambers for an entre growing season. Seeds were planted singly in 2.5 1 pots filled with locally derived, low fertility soil (160 plants per CO[sub 2] treatment). Net CO[sub 2] assimilation increased 25% in vegetative plants and 48% in reproductive plants growing at elevated p(CO[sub 2]). Every flower was hand-pollinated to mimicmore » natural pollination levels. Lifetime fecundity was greater in the elevated CO[sub 2] treatment, but the magnitude of this effect differed dramatically among paternal sibships: seed production increased 13% overall, yet among paternal sibships seed production varied between 0% and 50% more seeds in elevated p(CO[sub 2]) as compared to ambient. Our results suggest that natural selection can occur due to genotypic differences in the CO[sub 2] response. This process should be considered in estimates of long-term effects of elevated p(CO[sub 2]), especially with regard to anticipated increases in primary productivity.« less

Long-term manure application increased greenhouse gas emissions but had no effect on ammonia volatilization in a Northern China upland field.

PubMed

Zhang, Tao; Liu, Hongbin; Luo, Jiafa; Wang, Hongyuan; Zhai, Limei; Geng, Yucong; Zhang, Yitao; Li, Jungai; Lei, Qiuliang; Bashir, Muhammad Amjad; Wu, Shuxia; Lindsey, Stuart

2018-08-15

The impacts of manure application on soil ammonia (NH 3 ) volatilization and greenhouse gas (GHG) emissions are of interest for both agronomic and environmental reasons. However, how the swine manure addition affects greenhouse gas and N emissions in North China Plain wheat fields is still unknown. A long-term fertilization experiment was carried out on a maize-wheat rotation system in Northern China (Zea mays L-Triticum aestivum L.) from 1990 to 2017. The experiment included four treatments: (1) No fertilizer (CK), (2) single application of chemical fertilizers (NPK), (3) NPK plus 22.5t/ha swine manure (NPKM), (4) NPK plus 33.7t/ha swine manure (NPKM+). A short-term fertilization experiment was conducted from 2016 to 2017 using the same treatments in a field that had been abandoned for decades. The emissions of NH 3 and GHGs were measured during the wheat season from 2016 to 2017. Results showed that after long-term fertilization the wheat yields for NPKM treatment were 7105kg/ha, which were higher than NPK (3880kg/ha) and NPKM+ treatments (5518kg/ha). The wheat yields were similar after short-term fertilization (6098-6887kg/ha). The NH 3 -N emission factors (EF amm ) for NPKM and NPKM+ treatments (1.1 and 1.1-1.4%, respectively) were lower than NPK treatment (2.2%) in both the long and short-term fertilization treatments. In the long- and short-term experiments the nitrous oxide (N 2 O) emission factors (EF nit ) for NPKM+ treatment were 4.2% and 3.7%, respectively, which were higher than for the NPK treatment (3.5% and 2.5%, respectively) and the NPKM treatment (3.6% and 2.2%, respectively). In addition, under long and short-term fertilization, the greenhouse gas intensities for the NPKM+ treatment were 33.7 and 27.0kg CO 2 -eq/kg yield, respectively, which were higher than for the NPKM treatment (22.8 and 21.1kg CO 2 -eq/kg yield, respectively). These results imply that excessive swine manure application does not increase yield but increases GHG emissions. Copyright © 2018 Elsevier B.V. All rights reserved.

Elevated atmospheric CO2 increases microbial growth rates and enzymes activity in soil

NASA Astrophysics Data System (ADS)

Blagodatskaya, Evgenia; Blagodatsky, Sergey; Dorodnikov, Maxim; Kuzyakov, Yakov

2010-05-01

Increasing the belowground translocation of assimilated carbon by plants grown under elevated CO2 can cause a shift in the structure and activity of the microbial community responsible for the turnover of organic matter in soil. We investigated the long-term effect of elevated CO2 in the atmosphere on microbial biomass and specific growth rates in root-free and rhizosphere soil. The experiments were conducted under two free air carbon dioxide enrichment (FACE) systems: in Hohenheim and Braunschweig, as well as in the intensively managed forest mesocosm of the Biosphere 2 Laboratory (B2L) in Oracle, AZ. Specific microbial growth rates (μ) were determined using the substrate-induced respiration response after glucose and/or yeast extract addition to the soil. We evaluated the effect of elevated CO2 on b-glucosidase, chitinase, phosphatase, and sulfatase to estimate the potential enzyme activity after soil amendment with glucose and nutrients. For B2L and both FACE systems, up to 58% higher μ were observed under elevated vs. ambient CO2, depending on site, plant species and N fertilization. The μ-values increased linearly with atmospheric CO2 concentration at all three sites. The effect of elevated CO2 on rhizosphere microorganisms was plant dependent and increased for: Brassica napus=Triticum aestivum

Azotobacter chroococcum as a potentially useful bacterial biofertilizer for cotton (Gossypium hirsutum): Effect in reducing N fertilization.

PubMed

Romero-Perdomo, Felipe; Abril, Jorge; Camelo, Mauricio; Moreno-Galván, Andrés; Pastrana, Iván; Rojas-Tapias, Daniel; Bonilla, Ruth

The aim of this research was to evaluate whether the application of two plant growth-promoting (rhizo)bacteria might reduce nitrogen fertilization doses in cotton. We used strains Azotobacter chroococcum AC1 and AC10 for their proven ability to promote seed germination and cotton growth. These microorganisms were characterized by their plant growth-promoting activities. Then, we conducted a glasshouse study to evaluate the plant growth promoting ability of these strains with reduced doses of urea fertilization in cotton. Results revealed that both strains are capable of fixing nitrogen, solubilizing phosphorus, synthesizing indole compounds and producing hydrolytic enzymes. After 12 weeks, the glasshouse experiment showed that cotton growth was positively influenced due to bacterial inoculation with respect to chemical fertilization. Notably, we observed that microbial inoculation further influenced plant biomass (p<0.05) than nitrogen content. Co-inoculation, interestingly, exhibited a greater beneficial effect on plant growth parameters compared to single inoculation. Moreover, similar results without significant statistical differences were observed among bacterial co-inoculation plus 50% urea and 100% fertilization. These findings suggest that co-inoculation of A. chroococcum strains allow to reduce nitrogen fertilization doses up to 50% on cotton growth. Our results showed that inoculation with AC1 and AC10 represents a viable alternative to improve cotton growth while decreasing the N fertilizer dose and allows to alleviate the environmental deterioration related to N pollution. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Duke FACE -- Forest-Atmosphere Carbon Transfer and Storage (FACTS I)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oren, Ram

The Duke FACE experiment increases atmospheric [CO 2] to a height of 25 m in four 30-m diameter plots, each containing ~100 canopy trees and many sub-canopy individuals. The experiment was initiated in 1994 with CO 2 fumigation of the prototype plot, and reached full CO 2-fumigation capacity in 1996 when three additional FACE plots came on line. All elevated plots enriched the atmospheric CO 2 concentration by 200 ppmv relative to paired, ambient-CO 2 plots. Formalizing the analysis of CO 2 x N interactions, in March of 2005 each of the six FACE plots established in 1996 was trenchedmore » in half, and one half plot fertilized with nitrogen (N) at a rate of 11 g m -2 yr -1, following the approach established in 1998 in the prototype and its reference plot. The δ 13C of the fumigated plots’ atmosphere was -42.6‰, and while the 15N of the fertilizer did not affect the δ 15N of tissues directly it greatly reduced the effect of a 15N tracer study on tissue δ 15N. The CO 2 enrichment was completed in early November, 2010. Prior to termination of fumigation, 1-8 branches from 4-5 Pinus taeda individuals in each half plot were harvested, as well as most Juniperus occidentalis and broadleaved individuals <2 cm in diameter (1.4 m aboveground), including vine and herbaceous individuals. Following the termination, all individuals <8 cm in diameter, followed by all remaining individuals were harvested in half of each plot (a quarter in each CO 2 X N treatment). In all, 189 m 3 of dry material and 826 m 3 of wet material, or a total of 1014 m 3 of material is stored in various suited settings. The project quantified the effect of CO 2 X N on carbon uptake, allocation to various pools, accumulation of carbon in these pools, the release of carbon to the atmosphere, and factors controlling these processes. The project also assessed the effect of CO 2 X N on the components of the water budget, and related processes, as well as on the amount and diversity of understory vegetation.« less

The growth response of Alternanthera philoxeroides in a simulated post-combustion emission with ultrahigh [CO2] and acidic pollutants.

PubMed

Xu, Cheng-Yuan; Griffin, Kevin L; Blazier, John C; Craig, Elizabeth C; Gilbert, Dominique S; Sritrairat, Sanpisa; Anderson, O Roger; Castaldi, Marco J; Beaumont, Larry

2009-07-01

Although post-combustion emissions from power plants are a major source of air pollution, they contain excess CO2 that could be used to fertilize commercial greenhouses and stimulate plant growth. We addressed the combined effects of ultrahigh [CO2] and acidic pollutants in flue gas on the growth of Alternanthera philoxeroides. When acidic pollutants were excluded, the biomass yield of A. philoxeroides saturated near 2000 micromol mol(-1) [CO2] with doubled biomass accumulation relative to the ambient control. The growth enhancement was maintained at 5000 micromol mol(-1) [CO2], but declined when [CO2] rose above 1%, in association with a strong photosynthetic inhibition. Although acidic components (SO2 and NO2) significantly offset the CO2 enhancement, the aboveground yield increased considerably when the concentration of pollutants was moderate (200 times dilution). Our results indicate that using excess CO2 from the power plant emissions to optimize growth in commercial green house could be viable.

The Combination of Trichoderma harzianum and Chemical Fertilization Leads to the Deregulation of Phytohormone Networking, Preventing the Adaptive Responses of Tomato Plants to Salt Stress.

PubMed

Rubio, M B; Hermosa, Rosa; Vicente, Rubén; Gómez-Acosta, Fabio A; Morcuende, Rosa; Monte, Enrique; Bettiol, Wagner

2017-01-01

Plants have evolved effective mechanisms to avoid or reduce the potential damage caused by abiotic stresses. In addition to biocontrol abilities, Trichoderma genus fungi promote growth and alleviate the adverse effects caused by saline stress in plants. Morphological, physiological, and molecular changes were analyzed in salt-stressed tomato plants grown under greenhouse conditions in order to investigate the effects of chemical and biological fertilizations. The application of Trichoderma harzianum T34 to tomato seeds had very positive effects on plant growth, independently of chemical fertilization. The application of salt stress significantly changed the parameters related to growth and gas-exchange rates in tomato plants subject to chemical fertilization. However, the gas-exchange parameters were not affected in unfertilized plants under the same moderate saline stress. The combined application of T34 and salt significantly reduced the fresh and dry weights of NPK-fertilized plants, while the opposite effects were detected when no chemical fertilization was applied. Decaying symptoms were observed in salt-stressed and chemically fertilized plants previously treated with T34. This damaged phenotype was linked to significantly higher intercellular CO 2 and slight increases in stomatal conductance and transpiration, and to the deregulation of phytohormone networking in terms of significantly lower expression levels of the salt overlay sensitivity 1 ( SOS1 ) gene, and the genes involved in signaling abscisic acid-, ethylene-, and salicylic acid-dependent pathways and ROS production, in comparison with those observed in salt-challenged NPK-fertilized plants.

Modification of land-atmosphere interactions by CO2 effects

NASA Astrophysics Data System (ADS)

Lemordant, Leo; Gentine, Pierre

2017-04-01

Plant stomata couple the energy, water and carbon cycles. Increased CO2 modifies the seasonality of the water cycle through stomatal regulation and increased leaf area. As a result, the water saved during the growing season through higher water use efficiency mitigates summer dryness and the impact of potential heat waves. Land-atmosphere interactions and CO2 fertilization together synergistically contribute to increased summer transpiration. This, in turn, alters the surface energy budget and decreases sensible heat flux, mitigating air temperature rise. Accurate representation of the response to higher CO2 levels, and of the coupling between the carbon and water cycles are therefore critical to forecasting seasonal climate, water cycle dynamics and to enhance the accuracy of extreme event prediction under future climate.

Soil fertility controls soil-atmosphere carbon dioxide and methane fluxes in a tropical landscape converted from lowland forest to rubber and oil palm plantations

NASA Astrophysics Data System (ADS)

Hassler, E.; Corre, M. D.; Tjoa, A.; Damris, M.; Utami, S. R.; Veldkamp, E.

2015-10-01

Expansion of palm oil and rubber production, for which global demand is increasing, causes rapid deforestation in Sumatra, Indonesia, and is expected to continue in the next decades. Our study aimed to (1) quantify changes in soil CO2 and CH4 fluxes with land-use change and (2) determine their controlling factors. In Jambi Province, Sumatra, we selected two landscapes on heavily weathered soils that differ mainly in texture: loam and clay Acrisol soils. In each landscape, we investigated the reference land-use types (forest and secondary forest with regenerating rubber) and the converted land-use types (rubber, 7-17 years old, and oil palm plantations, 9-16 years old). We measured soil CO2 and CH4 fluxes monthly from December 2012 to December 2013. Annual soil CO2 fluxes from the reference land-use types were correlated with soil fertility: low extractable phosphorus (P) coincided with high annual CO2 fluxes from the loam Acrisol soil that had lower fertility than the clay Acrisol soil (P < 0.05). Soil CO2 fluxes from the oil palm (107.2 to 115.7 mg C m-2 h-1) decreased compared to the other land-use types (between 178.7 and 195.9 mg C m-2 h-1; P < 0.01). Across land-use types, annual CO2 fluxes were positively correlated with soil organic carbon (C) and negatively correlated with 15N signatures, extractable P and base saturation. This suggests that the reduced soil CO2 fluxes from oil palm were the result of strongly decomposed soil organic matter and reduced soil C stocks due to reduced litter input as well as being due to a possible reduction in C allocation to roots due to improved soil fertility from liming and P fertilization in these plantations. Soil CH4 uptake in the reference land-use types was negatively correlated with net nitrogen (N) mineralization and soil mineral N, suggesting N limitation of CH4 uptake, and positively correlated with exchangeable aluminum (Al), indicating a decrease in methanotrophic activity at high Al saturation. Reduction in soil CH4 uptake in the converted land-use types (ranging from -3.0 to -14.9 μg C m-2 h-1) compared to the reference land-use types (ranging from -20.8 to -40.3 μg C m-2 h-1; P < 0.01) was due to a decrease in soil N availability in the converted land-use types. Our study shows for the first time that differences in soil fertility control the soil-atmosphere exchange of CO2 and CH4 in a tropical landscape, a mechanism that we were able to detect by conducting this study on the landscape scale.

Field-Based Estimates of Global Warming Potential in Bioenergy Systems of Hawaii: Crop Choice and Deficit Irrigation.

PubMed

Pawlowski, Meghan N; Crow, Susan E; Meki, Manyowa N; Kiniry, James R; Taylor, Andrew D; Ogoshi, Richard; Youkhana, Adel; Nakahata, Mae

2017-01-01

Replacing fossil fuel with biofuel is environmentally viable from a climate change perspective only if the net greenhouse gas (GHG) footprint of the system is reduced. The effects of replacing annual arable crops with perennial bioenergy feedstocks on net GHG production and soil carbon (C) stock are critical to the system-level balance. Here, we compared GHG flux, crop yield, root biomass, and soil C stock under two potential tropical, perennial grass biofuel feedstocks: conventional sugarcane and ratoon-harvested, zero-tillage napiergrass. Evaluations were conducted at two irrigation levels, 100% of plantation application and at a 50% deficit. Peaks and troughs of GHG emission followed agronomic events such as ratoon harvest of napiergrass and fertilization. Yet, net GHG flux was dominated by carbon dioxide (CO2), as methane was oxidized and nitrous oxide (N2O) emission was very low even following fertilization. High N2O fluxes that frequently negate other greenhouse gas benefits that come from replacing fossil fuels with agronomic forms of bioenergy were mitigated by efficient water and fertilizer management, including direct injection of fertilizer into buried irrigation lines. From soil intensively cultivated for a century in sugarcane, soil C stock and root biomass increased rapidly following cultivation in grasses selected for robust root systems and drought tolerance. The net soil C increase over the two-year crop cycle was three-fold greater than the annualized soil surface CO2 flux. Deficit irrigation reduced yield, but increased soil C accumulation as proportionately more photosynthetic resources were allocated belowground. In the first two years of cultivation napiergrass did not increase net greenhouse warming potential (GWP) compared to sugarcane, and has the advantage of multiple ratoon harvests per year and less negative effects of deficit irrigation to yield.

Field-Based Estimates of Global Warming Potential in Bioenergy Systems of Hawaii: Crop Choice and Deficit Irrigation

PubMed Central

Meki, Manyowa N.; Kiniry, James R.; Taylor, Andrew D.; Ogoshi, Richard; Youkhana, Adel; Nakahata, Mae

2017-01-01

Replacing fossil fuel with biofuel is environmentally viable from a climate change perspective only if the net greenhouse gas (GHG) footprint of the system is reduced. The effects of replacing annual arable crops with perennial bioenergy feedstocks on net GHG production and soil carbon (C) stock are critical to the system-level balance. Here, we compared GHG flux, crop yield, root biomass, and soil C stock under two potential tropical, perennial grass biofuel feedstocks: conventional sugarcane and ratoon-harvested, zero-tillage napiergrass. Evaluations were conducted at two irrigation levels, 100% of plantation application and at a 50% deficit. Peaks and troughs of GHG emission followed agronomic events such as ratoon harvest of napiergrass and fertilization. Yet, net GHG flux was dominated by carbon dioxide (CO2), as methane was oxidized and nitrous oxide (N2O) emission was very low even following fertilization. High N2O fluxes that frequently negate other greenhouse gas benefits that come from replacing fossil fuels with agronomic forms of bioenergy were mitigated by efficient water and fertilizer management, including direct injection of fertilizer into buried irrigation lines. From soil intensively cultivated for a century in sugarcane, soil C stock and root biomass increased rapidly following cultivation in grasses selected for robust root systems and drought tolerance. The net soil C increase over the two-year crop cycle was three-fold greater than the annualized soil surface CO2 flux. Deficit irrigation reduced yield, but increased soil C accumulation as proportionately more photosynthetic resources were allocated belowground. In the first two years of cultivation napiergrass did not increase net greenhouse warming potential (GWP) compared to sugarcane, and has the advantage of multiple ratoon harvests per year and less negative effects of deficit irrigation to yield. PMID:28052075

The Effect of Low Carbohydrate Diets on Fertility Hormones and Outcomes in Overweight and Obese Women: A Systematic Review

PubMed Central

McGrice, Melanie; Porter, Judi

2017-01-01

(1) Background: Medical interventions including assisted reproductive technologies have improved fertility outcomes for many sub-fertile couples. Increasing research interest has investigated the effect of low carbohydrate diets, with or without energy restriction. We aimed to systematically review the published literature to determine the extent to which low carbohydrate diets can affect fertility outcomes; (2) Methods: The review protocol was registered prospectively with Prospective Register for Systematic Reviews (registration number CRD42016042669) and followed Preferred Reporting Items For Systematic Reviews and Meta-Analyses guidelines. Infertile women were the population of interest, the intervention was low carbohydrate diets (less than 45% total energy from carbohydrates), compared to usual diet (with or without co-treatments). Four databases were searched from date of commencement until April 2016; a supplementary Google scholar search was also undertaken. Title and abstract, then full text review, were undertaken independently and in duplicate. Reference lists of included studies and relevant systematic reviews were checked to ensure that all relevant studies were identified for inclusion. Quality assessment was undertaken independently by both authors using the Quality Criteria Checklist for Primary Research. Outcome measures were improved fertility outcomes defined by an improvement in reproductive hormones, ovulation rates and/or pregnancy rates; (3) Results: Seven studies fulfilled the inclusion criteria and were included in the evidence synthesis. Interventions were diverse and included a combination of low carbohydrate diets with energy deficit or other co-treatments. Study quality was rated as positive for six studies, suggesting a low risk of bias, with one study rated as neutral. Of the six studies which reported changes in reproductive hormones, five reported significant improvements post intervention; (4) Conclusion: The findings of these studies suggest that low carbohydrate diets warrant further research to determine their effect. These randomised controlled trials should consider the effect of carbohydrates (with or without energy deficit) on hormonal and fertility outcomes. PMID:28264433

The effect of follicle age on pregnancy rate in beef cows

USDA-ARS?s Scientific Manuscript database

The objective of this study was to test the effect of age of the ovulatory follicle on fertility in beef cows. Ovulation was synchronized with the 5 d CO-Synch + CIDR program in multiparous (n = 171) and primiparous (n = 130) postpartum beef cows in two groups (G1 and G2) before application of treat...

The effect of Follicle Age on Pregnancy Rate in Beef Cows

USDA-ARS?s Scientific Manuscript database

The objective of this study was to test the effect of age of the ovulatory follicle on fertility in beef cows. Ovulation was synchronized with the 5 d CO-Synch + CIDR program in multiparous (n = 171) and primiparous (n = 130) postpartum beef cows in two groups (G1 and G2) before application of treat...

[Effects of superphosphate addition on NH3 and greenhouse gas emissions during vegetable waste composting].

PubMed

Yang, Yan; Sun, Qin-ping; Li, Ni; Liu, Chun-sheng; Li, Ji-jin; Liu, Ben-sheng; Zou, Guo-yuan

2015-01-01

To study the effects of superphosphate (SP) on the NH, and greenhouse gas emissions, vegetable waste composting was performed for 27 days using 6 different treatments. In addition to the controls, five vegetable waste mixtures (0.77 m3 each) were treated with different amounts of the SP additive, namely, 5%, 10%, 15%, 20% and 25%. The ammonia volatilization loss and greenhouse gas emissions were measured during composting. Results indicated that the SP additive significantly decreased the ammonia volatilization and greenhouse gas emissions during vegetable waste composting. The additive reduced the total NH3 emission by 4.0% to 16.7%. The total greenhouse gas emissions (CO2-eq) of all treatments with SP additives were decreased by 10.2% to 20.8%, as compared with the controls. The NH3 emission during vegetable waste composting had the highest contribution to the greenhouse effect caused by the four different gases. The amount of NH3 (CO2-eq) from each treatment ranged from 59.90 kg . t-1 to 81.58 kg . t-1; NH3(CO2-eq) accounted for 69% to 77% of the total emissions from the four gases. Therefore, SP is a cost-effective phosphorus-based fertilizer that can be used as an additive during vegetable waste composting to reduce the NH3 and greenhouse gas emissions as well as to improve the value of compost as a fertilizer.

Effects of N loading rate on CH4 and N2O emissions during cultivation and fallow periods from forage rice fields fertilized with liquid cattle waste.

PubMed

Riya, S; Zhou, S; Kobara, Y; Sagehashi, M; Terada, A; Hosomi, M

2015-09-15

The use of liquid cattle waste (LCW) as a fertilizer for forage rice is important for material recycling because it can promote biomass production, and reduce the use of chemical fertilizer. Meanwhile, increase in emission of greenhouse gases (GHGs), especially CH4 and N2O would be concerned. We conducted a field study to determine the optimum loading rate of LCW as N to promote forage rice growth with lower GHG emissions. The LCW was applied to forage rice fields, N100, N250, N500, and N750, at four different N loading rates of 107, 258, 522, and 786 kg N ha(-1), respectively, including 50 kg N ha(-1) of basal chemical fertilizer. The above-ground biomass yields increased 14.6-18.5 t ha(-1) with increases in N loading rates. During the cultivation period, both the CH4 and N2O fluxes increased with increases in LCW loading rates. In the treatments of N100, N250, N500, and N750, the cumulative CH4 emissions during the entire period, including cultivation and fallow period were 29.6, 18.1, 54.4, and 67.5 kg C ha(-1), respectively, whereas those of N2O were -0.15, -0.02, 1.49, and 5.82 kg N ha(-1), respectively. Considering the greenhouse gas emissions and above-ground biomass, the yield-scaled CO2-equivalents (CO2-eqs) were 66.3, 35.9, 161, and 272 kg CO2 t(-1) for N100, N250, N500, and N750, respectively. These results suggest that N250 is the most appropriate LCW loading rate for promoting forage rice production with lower GHG emissions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rain pulses - how different data streams provide insight in response-times and help to attribute biophysical properties to ecosystem processes.

NASA Astrophysics Data System (ADS)

El-Madany, T. S.; Migliavacca, M.; Perez-Priego, O.; Luo, Y.; Kolle, O.; Carrara, A.; Moreno, G.; Reichstein, M.

2017-12-01

Rain pulses play a major role for the carbon cycle in semiarid ecosystems, as they can release large amounts of stored carbon. Physical and biological processes, triggered by the availability of water start to develop on various time scales and are dependent on the amount of available water. Especially, in savanna type ecosystems with an herbaceous understory and sparsely distributed trees the response time of the two plant functional types to rain pulses might be different. We present results from an ongoing large-scale nutrient manipulation experiment (MANIP) in a Mediterranean savanna type ecosystem and its response to rain pulses. Within MANIP the footprint areas from two out of three ecosystem eddy co-variance (EC) sites were fertilized with nitrogen (NT) and nitrogen plus phosphorous (NPT), the third served as the control (CT). The analysis combines EC data to determine the net ecosystem exchange, PhenoCam data to define the senescence and re-greening period, SAP-flow measurements to evaluate the response of trees to rain pulses, high frequency (1 Hz) CO2-concentration measurements to estimate the response time to of the ecosystem to rain pulses, and meteorological measurements to quantify the intensity of the rain pulses. Additionally, at NT canopy reflectance and SIF are measured continuously for trees and grasses. The combination of SIF and SAP-flow measurements allows to separate the contribution of trees to ecosystem fluxes and can be utilized to partition NEE into ecosystem respiration and gross primary productivity during the senescence period. The analyses focus on three topics; (i) utilizing high frequency dynamics of CO2 concentration to disentangle physical and biological responses to water availability; (ii) fertilization effect of respiration pulses on ecosystem fluxes; (iii) response of tree transpiration to rain pulses. CO2 concentrations show an instantaneous reaction to rain fall. Within minutes concentrations increase strongly and follow distinct patterns. The fertilization effect is not clear in terms of respiration magnitude triggered by the rain pulse but the fertilized areas show slightly more carbon uptake during daytime after a precipitation pulse. Sap-flow measurements indicate a response of the trees to the rain pulses which effect nocturnal and daytime sap velocities.

Partitioning direct and indirect effects reveals the response of water-limited ecosystems to elevated CO2.

PubMed

Fatichi, Simone; Leuzinger, Sebastian; Paschalis, Athanasios; Langley, J Adam; Donnellan Barraclough, Alicia; Hovenden, Mark J

2016-10-24

Increasing concentrations of atmospheric carbon dioxide are expected to affect carbon assimilation and evapotranspiration (ET), ultimately driving changes in plant growth, hydrology, and the global carbon balance. Direct leaf biochemical effects have been widely investigated, whereas indirect effects, although documented, elude explicit quantification in experiments. Here, we used a mechanistic model to investigate the relative contributions of direct (through carbon assimilation) and indirect (via soil moisture savings due to stomatal closure, and changes in leaf area index) effects of elevated CO 2 across a variety of ecosystems. We specifically determined which ecosystems and climatic conditions maximize the indirect effects of elevated CO 2 The simulations suggest that the indirect effects of elevated CO 2 on net primary productivity are large and variable, ranging from less than 10% to more than 100% of the size of direct effects. For ET, indirect effects were, on average, 65% of the size of direct effects. Indirect effects tended to be considerably larger in water-limited ecosystems. As a consequence, the total CO 2 effect had a significant, inverse relationship with the wetness index and was directly related to vapor pressure deficit. These results have major implications for our understanding of the CO 2 response of ecosystems and for global projections of CO 2 fertilization, because, although direct effects are typically understood and easily reproducible in models, simulations of indirect effects are far more challenging and difficult to constrain. Our findings also provide an explanation for the discrepancies between experiments in the total CO 2 effect on net primary productivity.

Effects of elevated atmospherical CO2 concentration and nitrogen fertilisation on priming effects in soils

NASA Astrophysics Data System (ADS)

Ohm, H.; Marschner, B.

2009-04-01

It is expected that the biomass production and thus the input of organic carbon to the soil will increase in response to elevated CO¬2 concentrations in the atmosphere. It remains unclear whether this will lead to a long term increased carbon pool, because only little is known about the stability of the additional carbon inputs. The soil samples were taken on an agricultural field at the experimental farm of the Federal Agricultural Research Centre (FAL) in Braunschweig, Germany. A Free-Air Carbon-dioxide Enrichment (FACE) system was installed here in May 2000. It consists of rings with 20 m diameter. Two rings were operated with CO2 enriched air (550 ppm), another two rings received ambient air (370 ppm). One half of each ring received the full amount of nitrogen fertiliser, the remainder received only half of this N-amount. The soil samples were taken after 6 years of operation and were incubated with 14C-labeled fructose and alanine for 21 days. Furthermore, combined additions with the respective substrate and ammonium nitrate or ammonium nitrate alone were conducted. The microbial biomass was determined after 2 and 21 days. In the untreated controls the SOC mineralisation amounted to 0.59 to 0.68%. The addition of fructose, fructose+NH4NO3, alanine and alanine+NH4NO3 to the different soil samples increased SOC mineralization and thus caused priming effects of different extents. For NH4NO3 no priming effects occurred. The addition of fructose induced positive priming effects in all samples. The lowest priming effect was observed in the sample ambient CO2+50% N (+50%), either with fructose alone or in combination with NH4NO3. The addition of alanine caused similar priming effects in the ambient CO2+100% N and the elevated CO2+100% N samples (+92.4 and +95.6%, respectively). Again, the lowest priming effect was observed in the sample ambient CO2+50% N. The microbial biomass showed a clear increase in the substrate treated samples compared to the controls. The addition of NH4NO3 did not change the amount of Cmic. The results show, that in no treatment SOC degradation was N-limited, but always limited by easily available energy substrates. On the other hand, N-fertilization had a stronger effect on the microbial response to alanine addition than the CO2-level. Only with low N-fertilization, soils under elevated CO2 are more substrate limited than under elevated CO2, indicating that biomass C-inputs are of different quality.

Elevated CO2 can modify the response to a water status gradient in a steppe grass: from cell organelles to photosynthetic capacity to plant growth.

PubMed

Jiang, Yanling; Xu, Zhenzhu; Zhou, Guangsheng; Liu, Tao

2016-07-12

The atmospheric CO2 concentration is rising continuously, and abnormal precipitation may occur more frequently in the future. Although the effects of elevated CO2 and drought on plants have been well reported individually, little is known about their interaction, particularly over a water status gradient. Here, we aimed to characterize the effects of elevated CO2 and a water status gradient on the growth, photosynthetic capacity, and mesophyll cell ultrastructure of a dominant grass from a degraded grassland. Elevated CO2 stimulated plant biomass to a greater extent under moderate changes in water status than under either extreme drought or over-watering conditions. Photosynthetic capacity and stomatal conductance were also enhanced by elevated CO2 under moderate drought, but inhibited with over-watering. Severe drought distorted mesophyll cell organelles, but CO2 enrichment partly alleviated this effect. Intrinsic water use efficiency (WUEi) and total biomass water use efficiency (WUEt) were increased by elevated CO2, regardless of water status. Plant structural traits were also found to be tightly associated with photosynthetic potentials. The results indicated that CO2 enrichment alleviated severe and moderate drought stress, and highlighted that CO2 fertilization's dependency on water status should be considered when projecting key species' responses to climate change in dry ecosystems.

Combined global change effects on ecosystem processesin nine U.S. topographically complex areas

USGS Publications Warehouse

Hartman, Melannie D.; Baron, Jill S.; Ewing, Holly A.; Weathers, Kathleen

2014-01-01

Concurrent changes in climate, atmospheric nitrogen (N) deposition, and increasing levels of atmospheric carbon dioxide (CO2) affect ecosystems in complex ways. The DayCent-Chem model was used to investigate the combined effects of these human-caused drivers of change over the period 1980–2075 at seven forested montane and two alpine watersheds in the United States. Net ecosystem production (NEP) increased linearly with increasing N deposition for six out of seven forested watersheds; warming directly increased NEP at only two of these sites. Warming reduced soil organic carbon storage at all sites by increasing heterotrophic respiration. At most sites, warming together with high N deposition increased nitrous oxide (N2O) emissions enough to negate the greenhouse benefit of soil carbon sequestration alone, though there was a net greenhouse gas sink across nearly all sites mainly due to the effect of CO2 fertilization and associated sequestration by plants. Over the simulation period, an increase in atmospheric CO2 from 350 to 600 ppm was the main driver of change in net ecosystem greenhouse gas sequestration at all forested sites and one of two alpine sites, but an additional increase in CO2 from 600 to 760 ppm produced smaller effects. Warming either increased or decreased net greenhouse gas sequestration, depending on the site. The N contribution to net ecosystem greenhouse gas sequestration averaged across forest sites was only 5–7 % and was negligible for the alpine. Stream nitrate (NO3−) fluxes increased sharply with N-loading, primarily at three watersheds where initial N deposition values were high relative to terrestrial N uptake capacity. The simulated results displayed fewer synergistic responses to warming, N-loading, and CO2 fertilization than expected. Overall, simulations with DayCent-Chem suggest individual site characteristics and historical patterns of N deposition are important determinants of forest or alpine ecosystem responses to global change.

Assessing environmental impacts of organic and inorganic fertilizer on daily and seasonal Greenhouse Gases effluxes in rice field

NASA Astrophysics Data System (ADS)

Yuan, Jing; Sha, Zhi-min; Hassani, Danial; Zhao, Zheng; Cao, Lin-kui

2017-04-01

According to the 5th Intergovernmental Panel on Climate Change evaluation report, the average surface temperature of the earth has escalated from 0.69 °C (1901) to 1.08 °C (2012), which is primarily ascribed to the anthropogenic emissions of Greenhouse Gases (GHGs). For the current study, a field experiment with four treatments, including chemical fertilizer, mixed fertilizer (MT), organic fertilizer (OT) and control (CK) was carried out in the Station of Long-term Fertilization Qingpu, Shanghai. The probable impact of fertilization on the average daily and accumulative emissions of GHGs were examined during different growth stages. The results indicated that fertilizer treatments considerably affected emissions of CH4, N2O and CO2. CH4 emitted most in OT, followed by MT, CT and CK, with the emissions of 77.29, 41.64, 30.20 and 17.37 kg ha-1, respectively. As for N2O emissions, there were no significant variations between CT (1.18 kg ha-1) and MT (1.05 kg ha-1), which were both higher than OT (0.66 kg ha-1) and CK (0.23 kg ha-1). CO2 emissions in CT (34 371 kg ha-1) came first, followed by MT (28 929 kg ha-1), OT (19 118 kg ha-1) and CK (11 533 kg ha-1), independently. Soil nutrients or fertility (humid acid, carbon, nitrogen, phosphorus, potassium and C: N) may perhaps speed up CH4 emissions, whilst drainage implicated could alleviate its production. Furthermore, applying substantial organic fertilizer at once might accelerate sudden and huge release of N2O. In addition, despite the inconsistencies among different years observed, the trend that organic fertilizer made the biggest amount of contribution to warming potential was alike. Consequently, the utilization of organic fertilizer should be mitigated, by applying some other inorganic fertilizers.

Management effects on greenhouse gas emissions from a fen covered with riverine silt

NASA Astrophysics Data System (ADS)

Bräuer, Melanie; Gatersleben, Peter; Tiemeyer, Bärbel

2017-04-01

Drainage is necessary to use peatlands for conventional agriculture, but this practice causes high emissions of the greenhouse gases carbon dioxide (CO2) and nitrous oxide (N2O). The effect of hydrological conditions and management on greenhouse gas (GHG) emissions from "true" peat soils is relatively well examined, but there is little data on GHG emissions from organic soils covered with mineral soil. Such a cover may either be man-made to improve the trafficability of the fields or natural, e.g. due to the deposition of riverine silt. Such mineral covers are widespread in North-Western Germany and other regions with intensively used peatlands. Here, we aim to evaluate the effect of management, water table depth and properties of the mineral cover on the emissions of CO2, N2O and methane (CH4). As the majority of peatlands in North-Western Germany, the study area is used as grassland. The area is artificially drained and intensively used (4 to 5 cuts per year, annual nitrogen fertilisation of 112 to 157 kg/ha). The fen peat with a thickness of 0.6 to 1.50 m is covered by riverine silt deposited by the river Weser. Six measurement sites have been chosen to represent typical agricultural management, soil properties and hydrological conditions of one hydrological management unit. The sites differ in the soil organic carbon (SOC) content of the riverine silt (4 - 15 % SOC), the occurrence of a ploughed horizon as well as water and agricultural management. We use static closed chambers to measure CO2, CH4 and N2O fluxes. CO2 measurement campaigns using transparent and opaque chambers and a portable IRGA take place every third or fourth week depending on season. CH4 and N2O samples are taken every second week and, in addition, on the first, third and seventh day after fertilizer application. Samples are analyzed by gas chromatography. First results show negligible CH4 fluxes due to low groundwater levels. Total N2O emissions reflected mainly the different fertilizer application rates although there were rarely specific N2O peaks directly after fertilizer application, probably due to low soil moisture during these periods. Estimated from the first six months of data, N2O emissions from peat soils covered with riverine silt are in the same range as emissions from true peat soils with comparable fertilisation rates. First results on CO2 emissions will be presented as well.

A seasonal carbon budget for a naturally iron-fertilized bloom over the Kerguelen Plateau in the Southern Ocean

NASA Astrophysics Data System (ADS)

Jouandet, Marie Paule; Blain, Stephane; Metzl, Nicolas; Brunet, Christian; Trull, Thomas W.; Obernosterer, Ingrid

2008-03-01

During the Kerguelen Ocean and Plateau compared Study (KEOPS, January-February 2005), a high-resolution distribution of surface fugacity of carbon dioxide ( fCO 2) was obtained from underway measurements. The stations in the core of the naturally iron-fertilized bloom were characterized by low fCO 2 (311±8 μatm) compared to the atmosphere, thus representing a large CO 2 sink. This contrasted with stations typical of high-nutrient low-chlorophyll (HNLC) conditions where the surface water was roughly in equilibrium with the atmosphere ( fCO 2=372±5 μatm). The vertical distribution of dissolved inorganic carbon (DIC) also was obtained at stations within and outside the bloom. Based on this data set, we constructed a carbon budget for the mixed layer that allowed us to determine the seasonal net community production (NCP season) and the seasonal carbon export in two contrasting environments. The robustness of the approach and the errors also were estimated. The NCP season in the core of the bloom was 6.6±2.2 mol m -2, typical of productive areas of the Southern Ocean. At the HNLC station the NCP season was 3 times lower than in the bloom. Our estimate of the daily net community production (NCP daily) within the bloom compares well with shipboard measurements of NCP. The NCP daily obtained above the Kerguelen Plateau was of the same order as the estimates from Southern Ocean artificial iron-fertilization experiments (SOIREE and EisenEx). The seasonal carbon export was derived from NCP season after subtraction of the seasonal accumulation of particulate and dissolved organic carbon. In the bloom, the carbon export (5.4±1.9 mol m -2) was 3-fold higher than at the HNLC station (1.7±0.4 mol m -2). Comparison of our results to artificial iron-fertilization experiments shows that the biological pump is enhanced by natural iron fertilization.

Substrate quality and nutrient availability influence CO2 production from tropical peat decomposition

NASA Astrophysics Data System (ADS)

Swails, E.; Jaye, D.; Verchot, L. V.; Hergoualc'h, K.; Wahyuni, N. S.; Borchard, N.; Lawrence, D.

2015-12-01

In Indonesia, peatlands are a major and growing source of greenhouse gas emissions due to increasing pressure from oil palm and pulp wood plantations. We are using a combination of field measures, laboratory experiments, and remote sensing to investigate relationships among land use, climatic factors and biogeochemical controls, and their influence on trace gas fluxes from tropical peat soils. Analysis of soils collected from peat sites on two major islands indicated substantial variation in peat substrate quality and nutrient content among land uses and geographic location. We conducted laboratory incubations to test the influence of substrate quality and nutrient availability on CO2 production from peat decomposition. Differences in peat characteristics attributable to land use change were tested by comparison of forest and oil palm peat samples collected from the same peat dome in Kalimantan. Regional differences in peat characteristics were tested by comparison of samples from Sumatra with samples from Kalimantan. We conducted additional experiments to test the influence of N and P availability and labile carbon on CO2 production. Under moisture conditions typical of oil palm plantations, CO2 production was higher from peat forest samples than from oil palm samples. CO2 production from Sumatra and Kalimantan oil palm samples was not different, despite apparent differences in nutrient content of these soils. N and P treatments representative of fertilizer application rates raised CO2 production from forest samples but not oil palm samples. Labile carbon treatments raised CO2 production in all samples. Our results suggest that decomposition of peat forest soils is nutrient limited, while substrate quality controls decomposition of oil palm soils post-conversion. Though fertilizer application could accelerate peat decomposition initially, fertilizer application may not influence long-term CO2 emissions from oil palm on peat.

Nitrogen Availability Dampens the Positive Impacts of CO2 Fertilization on Terrestrial Ecosystem Carbon and Water Cycles

NASA Astrophysics Data System (ADS)

He, Liming; Chen, Jing M.; Croft, Holly; Gonsamo, Alemu; Luo, Xiangzhong; Liu, Jane; Zheng, Ting; Liu, Ronggao; Liu, Yang

2017-11-01

The magnitude and variability of the terrestrial CO2 sink remain uncertain, partly due to limited global information on ecosystem nitrogen (N) and its cycle. Without N constraint in ecosystem models, the simulated benefits from CO2 fertilization and CO2-induced increases in water use efficiency (WUE) may be overestimated. In this study, satellite observations of a relative measure of chlorophyll content are used as a proxy for leaf photosynthetic N content globally for 2003-2011. Global gross primary productivity (GPP) and evapotranspiration are estimated under elevated CO2 and N-constrained model scenarios. Results suggest that the rate of global GPP increase is overestimated by 85% during 2000-2015 without N limitation. This limitation is found to occur in many tropical and boreal forests, where a negative leaf N trend indicates a reduction in photosynthetic capacity, thereby suppressing the positive vegetation response to enhanced CO2 fertilization. Based on our carbon-water coupled simulations, enhanced CO2 concentration decreased stomatal conductance and hence increased WUE by 10% globally over the 1982 to 2015 time frame. Due to increased anthropogenic N application, GPP in croplands continues to grow and offset the weak negative trend in forests due to N limitation. Our results also show that the improved WUE is unlikely to ease regional droughts in croplands because of increases in evapotranspiration, which are associated with the enhanced GPP. Although the N limitation on GPP increase is large, its associated confidence interval is still wide, suggesting an urgent need for better understanding and quantification of N limitation from satellite observations.

No Memory Effects of Restoration on N2O Exchange above an intensively managed Grassland in Switzerland

NASA Astrophysics Data System (ADS)

Merbold, L.; Decock, C.; Hörtnagl, L. J.; Fuchs, K.; Eugster, W.

2015-12-01

Here we present 3 consecutive years of EC flux measurements of N2O, CH4 and CO2) carried out in intensively managed grassland in Switzerland. Our measurements of greenhouse gas (GHG) concentrations were based on a recently developed CW-QCL absorption spectrometer to measure the concentrations of N2O and CH4 and an infrared gas analyzer to measure the concentrations of CO2 and H2O. We investigated the magnitude of trace gas emissions during a year of major disturbance (grassland restoration - including ploughing and fertilization in 2012) and the two following years representing business as usual (up to 6 harvests per year which are followed by fertilizer application, 2013 and 2014). We observed large peaks of N2O (up to 50 nmol m-2 s-1) in 2012 during thawing of the soil after the winter period and after re-sowing as well as inorganic fertilizer application at the beginning of summer. N2O emissions following harvest and fertilizer application ranged between 2 and 7 nmol m-2 s-1 and background fluxes were no larger than 1 nmol m-2 s-1. Fluxes of N2O were primarily controlled by soil water content and temperature, while management activities lead to larger variation of N2O fluxes during several days after the management event when compared to the background flux measurements. Annual flux budgets were dominated by CO2 emissions and N2O emissions contributed largely to the annual budget in 2012 but to a much lesser extend in the post-disturbance years (2013/2014). CH4 flux contribution to the annual budget was negligible. We conclude that grassland restoration results in large N2O emissions, while not leading to larger N2O emissions in subsequent years. Still, such specific time periods of enhanced N2O emissions need to be considered in decadal greenhouse gas budget estimates due to the fact that a single year can offset previous carbon and nitrogen sinks.

Agricultural management impact on greenhouse gas emissions

USDA-ARS?s Scientific Manuscript database

Management practices used on croplands to enhance crop yields and quality can contribute about 10 to 20% of global greenhouse gases (GHGs: carbon dioxide [CO2], nitrous oxide [N2O], and methane [CH4]). Some of these practices are tillage, cropping systems, N fertilization, organic fertilizer applica...

Accelerating forest growth enhancement due to climate and atmospheric changes in British Colombia, Canada over 1956-2001.

PubMed

Wu, Chaoyang; Hember, Robbie A; Chen, Jing M; Kurz, Werner A; Price, David T; Boisvenue, Céline; Gonsamo, Alemu; Ju, Weimin

2014-03-25

Changes in climate and atmospheric CO2 and nitrogen (N) over the last several decades have induced significant effects on forest carbon (C) cycling. However, contributions of individual factors are largely unknown because of the lack of long observational data and the undifferentiating between intrinsic factors and external forces in current ecosystem models. Using over four decades (1956-2001) of forest inventory data at 3432 permanent samples in maritime and boreal regions of British Columbia (B.C.), Canada, growth enhancements were reconstructed and partitioned into contributions of climate, CO2 and N after removal of age effects. We found that climate change contributed a particularly large amount (over 70%) of the accumulated growth enhancement, while the remaining was attributed to CO2 and N, respectively. We suggest that climate warming is contributing a widespread growth enhancement in B.C.'s forests, but ecosystem models should consider CO2 and N fertilization effects to fully explain inventory-based observations.

Global crop yield response to extreme heat stress under multiple climate change futures

NASA Astrophysics Data System (ADS)

Deryng, D.; Conway, D.; Ramankutty, N.; Price, J.; Warren, R.

2014-12-01

Extreme heat stress during the crop reproductive period can be critical for crop productivity. Projected changes in the frequency and severity of extreme climatic events are expected to negatively impact crop yields and global food production. This study applies the global crop model PEGASUS to quantify, for the first time at the global scale, impacts of extreme heat stress on maize, spring wheat and soybean yields resulting from 72 climate change scenarios for the 21st century. Our results project maize to face progressively worse impacts under a range of RCPs but spring wheat and soybean to improve globally through to the 2080s due to CO2 fertilization effects, even though parts of the tropic and sub-tropic regions could face substantial yield declines. We find extreme heat stress at anthesis (HSA) by the 2080s (relative to the 1980s) under RCP 8.5, taking into account CO2 fertilization effects, could double global losses of maize yield (dY = -12.8 ± 6.7% versus -7.0 ± 5.3% without HSA), reduce projected gains in spring wheat yield by half (dY = 34.3 ± 13.5% versus 72.0 ± 10.9% without HSA) and in soybean yield by a quarter (dY = 15.3 ± 26.5% versus 20.4 ± 22.1% without HSA). The range reflects uncertainty due to differences between climate model scenarios; soybean exhibits both positive and negative impacts, maize is generally negative and spring wheat generally positive. Furthermore, when assuming CO2 fertilization effects to be negligible, we observe drastic climate mitigation policy as in RCP 2.6 could avoid more than 80% of the global average yield losses otherwise expected by the 2080s under RCP 8.5. We show large disparities in climate impacts across regions and find extreme heat stress adversely affects major producing regions and lower income countries.

Global crop yield response to extreme heat stress under multiple climate change futures

NASA Astrophysics Data System (ADS)

Deryng, Delphine; Conway, Declan; Ramankutty, Navin; Price, Jeff; Warren, Rachel

2014-03-01

Extreme heat stress during the crop reproductive period can be critical for crop productivity. Projected changes in the frequency and severity of extreme climatic events are expected to negatively impact crop yields and global food production. This study applies the global crop model PEGASUS to quantify, for the first time at the global scale, impacts of extreme heat stress on maize, spring wheat and soybean yields resulting from 72 climate change scenarios for the 21st century. Our results project maize to face progressively worse impacts under a range of RCPs but spring wheat and soybean to improve globally through to the 2080s due to CO2 fertilization effects, even though parts of the tropic and sub-tropic regions could face substantial yield declines. We find extreme heat stress at anthesis (HSA) by the 2080s (relative to the 1980s) under RCP 8.5, taking into account CO2 fertilization effects, could double global losses of maize yield (ΔY = -12.8 ± 6.7% versus - 7.0 ± 5.3% without HSA), reduce projected gains in spring wheat yield by half (ΔY = 34.3 ± 13.5% versus 72.0 ± 10.9% without HSA) and in soybean yield by a quarter (ΔY = 15.3 ± 26.5% versus 20.4 ± 22.1% without HSA). The range reflects uncertainty due to differences between climate model scenarios; soybean exhibits both positive and negative impacts, maize is generally negative and spring wheat generally positive. Furthermore, when assuming CO2 fertilization effects to be negligible, we observe drastic climate mitigation policy as in RCP 2.6 could avoid more than 80% of the global average yield losses otherwise expected by the 2080s under RCP 8.5. We show large disparities in climate impacts across regions and find extreme heat stress adversely affects major producing regions and lower income countries.

Vulnerability of carbon storage in North American boreal forests to wildfires during the 21st century

USGS Publications Warehouse

Balshi, M. S.; McGuire, Anthony David; Duffy, P.; Flannigan, M.; Kicklighter, David W.; Melillo, J.

2009-01-01

The boreal forest contains large reserves of carbon. Across this region, wildfires influence the temporal and spatial dynamics of carbon storage. In this study, we estimate fire emissions and changes in carbon storage for boreal North America over the 21st century. We use a gridded data set developed with a multivariate adaptive regression spline approach to determine how area burned varies each year with changing climatic and fuel moisture conditions. We apply the process-based Terrestrial Ecosystem Model to evaluate the role of future fire on the carbon dynamics of boreal North America in the context of changing atmospheric carbon dioxide (CO2) concentration and climate in the A2 and B2 emissions scenarios of the CGCM2 global climate model. Relative to the last decade of the 20th century, decadal total carbon emissions from fire increase by 2.5–4.4 times by 2091–2100, depending on the climate scenario and assumptions about CO2fertilization. Larger fire emissions occur with warmer climates or if CO2 fertilization is assumed to occur. Despite the increases in fire emissions, our simulations indicate that boreal North America will be a carbon sink over the 21st century if CO2 fertilization is assumed to occur in the future. In contrast, simulations excluding CO2 fertilization over the same period indicate that the region will change to a carbon source to the atmosphere, with the source being 2.1 times greater under the warmer A2 scenario than the B2 scenario. To improve estimates of wildfire on terrestrial carbon dynamics in boreal North America, future studies should incorporate the role of dynamic vegetation to represent more accurately post-fire successional processes, incorporate fire severity parameters that change in time and space, account for human influences through increased fire suppression, and integrate the role of other disturbances and their interactions with future fire regime.

Depression of belowground respiration is more pronounced than enhancement of photosynthesis during the first year after nitrogen fertilization of a mature Pacific Northwest Douglas-fir forest

NASA Astrophysics Data System (ADS)

Chen, B.; Black, T. A.; Jassal, R.; Nesic, Z.; Bruemmer, C.

2008-05-01

Nitrogen (N) additions to forest have shown variable effects on both respiration and photosynthesis. With increasing rates of anthropogenic N deposition, there is a strong need to understand the ecosystem response to N inputs. We investigated how N fertilization affects the ecosystem carbon (C) balance of a 57-year-old coast Douglas-fir stand in British Columbia, Canada, based on eddy-covariance (EC) and soil-chamber (fertilized and control plots) measurements and process-based modeling. The stand was fertilized by helicopter with urea at 200 kg N ha-1 in January 2007. A land surface model (Ecosystem Atmosphere Simulation Scheme, EASS) was combined with an ecosystem model (Boreal Ecosystem Productivity Simulator, BEPS) and a coupled C and N subroutine was incorporated into the integrated EASS-BEPS model in this study. This half-hourly time step model was run continuously for the period from 2001 to 2007 in two scenarios: with and without fertilization. Modeled C fluxes without fertilization [net ecosystem productivity (NEP), gross primary productivity (GPP), ecosystem respiration (Re) and belowground respiration (Rs)] agreed well with EC and soil chamber measurements over diurnal, seasonal and annual time scales for 2001 to 2006; while simulated NEP, GPP, Re and Rs with fertilization reasonably followed EC and chamber measurements in 2007 (545 vs. 520, 2163 vs. 2155, 1618 vs. 1635, and 920 vs. 906 g C m-2 yr-1, respectively). Comparison of EC-determined C fluxes in 2007 with model simulations without fertilization suggests that annual Re decreased by 6.7% (1635 vs. 1752 g C m-2), gross primary productivity (GPP) increased by 6.8% (2155 vs. 2017 g C m-2), and annual NEP increased by 96.2% (520 vs. 265 g C m-2) due to fertilization. The modeled reduction in Rs (9.6%, comparing modeled values without and with fertilization: 1008 vs. 920 g C m-2 yr-1) is consistent with that measured using the soil chambers (~11.5%, comparing CO2 effluxes from control and fertilized plots measured from late summer to fall). The model also indicated that the effect of fertilization on aboveground (leaf and stem) respiration was very small. These experimental and modeling results suggest N fertilization significantly increased NEP mainly as a result of strongly reduced Rs (~10-12%) and moderately enhanced GPP (~6.8%) in the first year after fertilization.

The Effects of Elevated pCO2, Hypoxia and Temperature on ...

EPA Pesticide Factsheets

Estuarine fish are acclimated to living in an environment with rapid and frequent changes in temperature, salinity, pH, and dissolved oxygen (DO) levels; the physiology of these organisms is well suited to cope with extreme thermal, hypercapnic, and hypoxic stress. While the adverse effects of low dissolved oxygen levels on estuarine fish has been well-documented, the interaction between low DO and elevated pCO2 is not well understood. There is some evidence that low DO and elevated pCO2 interact antagonistically, however little information exists on how projected changes of pCO2 levels in near-shore waters may affect estuarine species, and how these changes may specifically interact with dissolved oxygen and temperature. We explored the survivability of 7-day post fertilization sheepshead minnow, Cyprinodon variegatus, using short term exposure to the combined effects of elevated pCO2 (~1300 µatm; IPCC RCP 8.5) and low dissolved oxygen levels (~2 mg/L). Additionally, we determined if the susceptibility of these fish to elevated pCO2 and low DO was influenced by increases in temperature from 27.5°C to 35°C. Results from this study and future studies will be used to identify estuarine species and lifestages sensitive to the combined effects of elevated pCO2 and low dissolved oxygen. This project was created in order to better understand the interactive effects of projected pCO2 levels and hypoxia in estuarine organisms. This work is currently focused on the se

In vitro embryo production in camel (Camelus dromedarius) from in vitro matured oocytes fertilized with epididymal spermatozoa stored at 4 degrees C.

PubMed

Wani, N A

2009-03-01

Experiments were conducted to study the effect of storing epididymal spermatozoa, in tris-tes- and tris-lactose egg yolk extenders, on their fertilizing ability and subsequent in vitro embryo development. Ovaries and testes were collected from a local slaughterhouse in normal saline solution (NSS) at 37 degrees C and on ice (0-1 degrees C), respectively. Cumulus oocyte complexes (COCs) aspirated from the follicles were randomly distributed to 4-well culture plates (20-25COCs/well) containing 500 microL of maturation medium and cultured at 38.5 degrees C in an atmosphere of 5% CO(2) in air for 36 h. Spermatozoa were collected from the cauda epididymides in syringes containing 2-3 mL of either tris-tes- or tris-lactose egg yolk extender. They were cooled down slowly and stored at refrigeration (4 degrees C) temperature. The spermatozoa were evaluated for motility and used for IVF of IVM oocytes on the day of collection and after 2, 4, 6 and 8 days of storage. On the day of IVF, spermatozoa were prepared by the swim up technique and both spermatozoa and oocytes were co-incubated at 38.5 degrees C in a humidified atmosphere of 5% CO(2) in air for 15-16 h. Presumptive zygotes were either fixed and stained with Hoechst 33342 for evaluation of fertilization or were cultured in 500 microL of the culture medium at 38.5 degrees C in an atmosphere of 5% CO(2), 5% O(2) and 90% N(2) in air. There was no significant difference (P>0.05) in the proportion of oocytes fertilized with spermatozoa stored in either of the two extenders for up to 8 days. The proportion of oocytes that cleaved (43-60%) and those that developed to blastocysts (14-21%) did not show any difference (P>0.05) either, when spermatozoa from different days of storage were used. First cleavage was observed as early as 16 h after IVF, early blastocysts had developed by day 4, expanded blastocysts after day 5 and hatching of blastocysts started after day 6 of culture. It may be concluded that dromedary epididymal spermatozoa survive in storage for at least 8 days in tris-lactose- and tris-tes egg yolk diluents at 4 degrees C. These spermatozoa maintain fertilizing ability and may be suitable for use in IVF and other assisted reproductive procedures.

Triticale (XTriticosecale W.) Heavy Metal Upptake as a Possibility of Food Chain Pollution in a Long-Term Field Experiment in Hungary

NASA Astrophysics Data System (ADS)

László Phd, M., ,, Dr.

2009-04-01

Some trace elements are dangerous because they tend to bioaccumulate in food chain. Bioaccumulation means an increase in the concentration of a chemical in a biological organism over time, compared to the chemical's concentration in they environment. Compounds accumulate in living things any time they are taken up and stored faster han they are broken down (metabolize) or extreted. Triticale is the stabilized man-made hybrid of wheat (Triticum eastivum L.) and rye (Secale cereale L.). Wheat-rye hybrids date back to 1875, it was only in 1953 that the first North American triticale breeding programme was initiated at the University Manitoba. Globally, triticale is used primary for livestock feed today. NPKCaMg fertilization effects were estimated on trace element bioavailability by Triticale in a long-term field experiment on a Haplic Luvisol (acidic sandy brown forest soil) at Nyírlugos in East-Hungary in 1998. Soil geochemical parameters were as follow: humus 0.6%, pH (H2O) 5.8, pH (KCl) 4.6, total N 32.8 mg . kg-1, AL (ammonium lactate soluble)- P2O5 43 mg . kg-1, AL-K2O 52 mg . kg-1. The experiments involved 32 NPKCaMg treatments and their combinations in 4 replications giving a total of 128 plots from 1980. N levels were 0, 50, 100, 150 kg . ha-1 . yr-1, P2O5 and K2O 0, 60, 120, 180 kg . ha-1 . yr-1, CaCO3 0, 250, 500, 1000 kg . ha-1 . yr-1 and MgCO3 doses were 0, 140, 280 kg . ha-1 . yr-1. Plot brutto size was 50 m2. The main results were as follows. Main soil chemical parameters depend on NPKCaMg treatments. Soil pH (H2O) and pH (KCl) values ranged from 4.6 to 6.3 and from 3.5 to 5.8 indicating wide range from extremely acidic to slightly acidic. Ca, Fe, Mg, Mn and Al element concentrations shown a large variability too in interaction with fertilization doses and pH values (Ca 36-594 mg . kg-1, Fe 61-90 mg . kg-1, Mg 5-42 mg . kg-1, Mn 16-36 mg . kg-1, Al 79-118 mg . kg-1). The better soil pH (H2O), pH (KCl) and Ca parameters resulted by NPKCaMg combinations [pH (H2O) 6.3, pH (KCl) 5.8, Ca 596 mg . kg-1]. Fe, Zn, B, Pb, Cr and Cd leaf+straw status was not influenced hardly by N treatments, but in case of the leaf+straw Co, concentration was significantly increasing. NP combination effects on Fe, Zn, B, Co, Pb, Cr and Cd were similar to N fertilization. Fe leafe+straw contents decreased strongly by NK effects. NPK and NPKCaMg nutrition growing up Pb accumulation to 1.5 mg . kg-1 [cereal average content (CAC) 0.3-0.6 mg . kg-1]. The experimental Zn, Cr, and Cd leaf+straw values not were on higher level than the CAC. The yield ranged from 0.9 t . ha-1 to 7.9 t . ha-1 on dependence of fertilization treatments. The NPKCaMg combinations yielded more around 9 times than the non fertilized plots. Fe, Zn, B, Co, Al, Sr and Cu grain status was not influenced significantly by N and NK treatments. The NP combination effects on Fe, Zn, B, Co, Al and Cu were similar to N fertilization, but in case of the Sr, concentration was dramatically increasing. Triticale seed Zn values not were on higher level than the CAC. Fe actual transfer index (ATI)(Márton, 2004) values are shown N and NPKCaMg fertilization plus effects on Fe translocation from soils to triticale grain. The Al ATI datas were on low level. These results shown Triticale have ability to Co, Pb and Sr accumulation from soil to crop and food chain to a different degree. Key words: trace element, bioavailability, Haplic Luvisol, triticale Introduction: Triticale is the stabilized man-made hybrid of wheat (Triticum eastivum L.) and rye (Secale cereale L.). Wheat-rye hybrids date back to 1875, it was only in 1953 that the first North American triticale breeding programme was initiated at the University Manitoba. Globally, triticale is used primary for livestock feed (Oelke et al. 1989). In Mexico, which grows the crop triticale is used mostly for whole-grain triticale breads and tortillas. In the US, triticale is harvested mostly for forage but there is a small market for pancake mixes and crackers due to a savory, nutty flavor. Etanol plants will pay a premium for triticale over barley since it has more starch and no hull, making alcohol production more efficient. Germany, France, China, Poland and Hungary account for nearly 90 percent of world triticale production (Donald et al. 2001). Heavy metals are dangerous because they tend to bioaccumulate in food chain. Bioaccumulation means an increase in the concentration of a chemical in a biological organism over time, compared to the chemical`s concentration in they environment. Compounds accumulate in living things any time they are taken up and stored faster han they are broken down (metabolize) or extreted. Crops have ability to heavy metal accumulation from fertilizers such as Cd, Pb, Cu, Zn etc. to a different degree (Lee et al. 2001, Scholz and Ellerbrock 2004). The main purposes of this study was to determine the triticale toxic element upptake by the soil, triticale leaf+straw and grain element concentrations on acid sandy soil in a long-term field fertilization experiment at Nyirlugos, Hungary in 1998. Material and Methods: Field experiments were carried out on an acidic sandy brown forest soil at Nyírlugos in East-Hungary from 1962 to 2005. Soil geochemical parameters were as follow: humus 0.6%, pH (H2O) 5.8, pH (KCl) 4.6, total N 32.8 mg/kg, AL (ammonium lactate soluble)- P2O5 43 mg/kg, AL-K2O 52 mg/kg. The experiments involved 32 NPKCaMg treatments in 4 replications giving a total of 128 plots. N levels were 0, 50, 100, 150 kg/ha/yr, P2O5 and K2O 0, 60, 120, 180 kg/ha/yr, CaCO3 0, 250, 500, 1000 kg/ha/yr and MgCO3 doses were 0, 140, 280 kg/ha/yr. Plot brutto size was 50 m2. Composite soil samples consisting of 25 subsamples collected at before flowering time from the ploughed layer of each plot. The so-called "mobile" fraction was extracted by ammonium-acetate+EDTA (AAc+EDTA, Lakanen and Ervio 1971) and the heavy metal determination by ICP-AES technic. Plant leaf+straw and seed samples taken at before flowering and at harvest time. Total element content measured after microwave digestion using cc. HNO3 + cc. H2O2 by ICP-AES technic. Actual translocation indexes (ATI=plant metal c./soil metal c.) determinated by Márton 2004. Datamatrixes estimated by SPSS biometrichal method. Results: Depend on NPKCaMg treatments soil pH (H2O) and pH (KCl) values ranged from 4.6 to 6.3 and from 3.5 to 5.8 indicating wide range from extremely acidic to slightly acidic. Ca, Fe, Mg, Mn and Al element concentrations shown a large variability too in interaction with fertilization doses and pH values (Ca 36-594 mg/kg, Fe 61-90 mg/kg, Mg 5-42 mg/kg, Mn 16-36 mg/kg, Al 79-118 mg/kg). The better soil pH (H2O), pH (KCl) and Ca parameters resulted by NPKCaMg combinations [pH (H2O) 6.3, pH (KCl) 5.8, Ca 596 mg/kg]. Fe, Zn, B, Co, Pb, Cr, and Cd element contents of triticale leaf+straw before flowering time presented in Table 2. Fe, Zn, B, Pb, Cr and Cd leaf+straw status was not influenced hardly by N treatments, but in case of the leaf+straw Co, concentration was significantly increasing. NP combination effects on Fe, Zn, B, Co, Pb, Cr and Cd were similar to N fertilization. Fe leafe+straw contents decreased strongly by NK effects. NPK and NPKCaMg nutrition growing up Pb accumulation to 1.5 mg/kg [cereal average content (CAC) 0.3-0.6 mg/kg. The experimental Zn, Cr, and Cd leaf+straw values not were on higher level than the CAC. The yield ranged from 0.9 t/ha to 7.9 t/ha on dependence of fertilization treatments. The NPKCaMg combinations yielded more around 9 times than the non fertilized plots. Fe, Zn, B, Co, Al, Sr and Cu grain status was not influenced significantly by N and NK treatments. The NP combination effects on Fe, Zn, B, Co, Al and Cu were similar to N fertilization, but in case of the Sr, concentration was dramatically increasing. Triticale seed Zn values not were on higher level than the CAC. Conclusions: Depend on NPKCaMg treatments soil pH (H2O) and pH (KCl) values ranged from 4.6-6.3 and 3.5-5.8 indicating wide range from extremely acidic to slightly acidic. The leaf+straw Co concentrations increased hardly by N treatment effects. NPK and NPKCaMg nutrition growing up Pb accumulation to 1.5 mg/kg [cereal average content (CAC) 0.3-0.6 mg/kg) in leaf+straw. The NPKCaMg combinations yielded more around 9 times than the non fertilized plots. The NP combination effects in case of the grain Sr concentration was dramatically increasing. These experimental results have demonstrated that triticale has a gerat ability to leaf+straw`s Co, Pb and grain`s Sr bioaccumulation. By this way Co, Pb and Sr can be enter to food chain. Acknowledgements: This study was supported by Applied Geochemistry and Geochemical Engineering School of Civil, Urban and Geosystem Engineering College of Engineering Seoul National University Seoul, Research Institute for Soil Sience and Agricultural Chemistry of the Hungarian Academy of Sciences Budapest and No.: E-2/04 Hungarian & Spanish International Project by Hungarian Technology & Sciences Foundation, Budapest. References Donald, S., Murray, McL., Trevor, S., Patricia, J. 2001. Triticale. Food and Rural Development Lacombe. Alberta Lee, C. G., Chon, H. T., Jung, M. C. 2001. Heavy metal contamination in the vicinity of the Daduk Au-Ag-Pb-Zn mine in Korea. Applied Geochemistry, 16:1377-1386. Márton, L. 2004. Research report for 2004. RISSAC-HAS, Budapest Oelke, E. A., Oplinger, E. S., Brinkman M. A. 1989. Alternative field crops manual. University Minnesota, University Visconsin. St. Paul, Madison Scholz, V., Ellerbrock, R. 2004. Environment friendly and energetically efficient cultivation of energy plants on sandy soil. IAB, ZAL. Potsdam

Fertility and social interaction at the workplace: Does childbearing spread among colleagues?

PubMed

Pink, Sebastian; Leopold, Thomas; Engelhardt, Henriette

2014-09-01

This research investigates whether colleagues' fertility influences women's transitions to parenthood. We draw on Linked-Employer-Employee data (1993-2007) from the German Institute for Employment Research comprising 33,119 female co-workers in 6579 firms. Results from discrete-time hazard models reveal social interaction effects on fertility among women employed in the same firm. In the year after a colleague gave birth, transition rates to first pregnancy double. This effect declines over time and vanishes after two years. Further analyses suggest that the influence of colleagues' fertility is mediated by social learning. Copyright © 2013 Elsevier Ltd. All rights reserved.

Potential effects of earthworm activity on C and N dynamics in tropical paddy soil

NASA Astrophysics Data System (ADS)

John, Katharina; Zaitsev, Andrey S.; Wolters, Volkmar

2016-04-01

Earthworms are involved in key ecosystem processes and are generally considered important for sustainable crop production. However, their provision of essential ecosystem services and contribution to tropical soil carbon and nitrogen balance in rice-based agroecosystems are not yet completely understood. We carried out two microcosm experiments to quantify the impact of a tropical earthworm Pheretima sp. from the Philippines on C and N turnover in rice paddy soils. First one was conducted to understand the modulation impact of soil water saturation level and nitrogen fertilizer input intensity on C and N cycles. The second one focused on the importance of additional organic matter (rice straw) amendment on the earthworm modulation of mineralization in non-flooded conditions. We measured CO2, CH4 (Experiments 1 and 2) and N2O evolution (Experiment 2) from rice paddy soil collected at the fields of the International Rice Research Institute (Philippines). Further we analysed changes in soil C and N content as well as nutrient loss via leaching induced by earthworms (Experiment 2). Addition of earthworms resulted in the strong increase of CH4 release under flooded conditions as well as after rice straw amendment. Compared to flooded conditions, earthworms suppressed the distinct CO2 respiration maximum at intermediate soil water saturation levels. In the first few days after the experiment establishment (Experiment 1) intensive nitrogen application resulted in the suppression of CO2 emission by earthworms at non-flooded soil conditions. However, at the longer term perspective addressed in the second experiment (30 days) earthworm activity rather increased average soil respiration under intensive fertilization or rice straw amendment. The lowest N2O release rates were revealed in the microcosms with earthworm and straw treatments. The combined effect of N fertilizer and straw addition to microcosms resulted in the increased leachate volume due to earthworm bioturbation activity. The mean relative C loss with leaching was increased by earthworms under intensive fertilization and consequently resulting soil C content in the end of Experiment 2 decreased. N concentration in the leachate remained unaffected by earthworms although the remaining N content in soil with straw application and earthworm treatment was significantly higher than in the control. Our results showed that the potential role of earthworms in C-stabilization is confined to moderately irrigated soils that allow high earthworm activity. Earthworm effects on C and N release under non-flooded conditions were largely modulated by the application of N fertilizer (urea) and by the amendment of rice straw. Our findings suggest that the presence of earthworms significantly affect C and N budgets in rice paddy soil, especially in the intensively managed non-flooded fields. In the short term perspective they sequester C and N loss from soil. However, in the longer term (ca. 30 days) this sequestration effect remains significant only for nitrogen under the straw application treatment. The study was supported by ICON project within the DFG-Research Unit FOR 1701.

Application of intracytoplasmic sperm injection (ICSI) for fertilization and development in birds.

PubMed

Shimada, Kiyoshi; Ono, Tamao; Mizushima, Shusei

2014-01-15

Intracytoplasmic sperm injection (ICSI) technology in birds has been hampered due to opacity of oocyte. We developed ICSI-assisted fertilization and gene transfer in quail. This paper reviews recent advances of our ICSI experiments. The oocyte retrieved from the oviduct and a quail sperm was injected into the oocyte under a stereomicroscope. The oocyte was cultured for 24h at 41°C under 5% CO2 in air. The fertilization and development was assessed by microscopic observation. The fertility rate ranged 12-18% and development varied from stage II to V in trials. To improve the fertility rate, phospholipase C (PLC) zeta was injected with a sperm. It was increased to 37-50%. Furthermore, injection of inositol trisphosphate increased to over 85%. Quail oocyte can be fertilized with chicken sperm and so can testicular elongated spermatid. To extend embryonic development, chicken eggshell was used as a surrogate culture at 37°C after the 24h incubation at 41°C under 5% CO2 in air. It survived up to 2days thereafter. Finally, gene transfer was attempted in quail egg. The sperm membrane was disrupted with Triton X-100 (TX-100) and was injected with PLCzeta cRNA and enhanced green fluorescent protein (EGFP) gene in oocyte. The GFP expression was evaluated at 24h incubation at 41°C under 5% CO2 in air in the embryos. While the expression was not detected in the control oocytes, the experimental treatment induced blastoderm development (44%) of the oocytes and 86% of blastoderm showed fluorescent emission. In addition, PCR analysis detected EGFP fragments in 50% of GFP-expressing blastoderm. Our ICSI method may be the first step toward the production of transgenic birds. Copyright © 2013 Elsevier Inc. All rights reserved.

Effect of elevated CO2, O3, and UV radiation on soils.

PubMed

Formánek, Pavel; Rejšek, Klement; Vranová, Valerie

2014-01-01

In this work, we have attempted to review the current knowledge on the impact of elevated CO2, O3, and UV on soils. Elevated CO2 increases labile and stabile soil C pool as well as efficiency of organic pollutants rhizoremediation and phytoextraction of heavy metals. Conversely, both elevated O3 and UV radiation decrease inputs of assimilates to the rhizosphere being accompanied by inhibitory effects on decomposition processes, rhizoremediation, and heavy metals phytoextraction efficiency. Contrary to elevated CO2, O3, or UV-B decreases soil microbial biomass, metabolisable C, and soil N t content leading to higher C/N of soil organic matter. Elevated UV-B radiation shifts soil microbial community and decreases populations of soil meso- and macrofauna via direct effect rather than by induced changes of litter quality and root exudation as in case of elevated CO2 or O3. CO2 enrichment or increased UV-B is hypothesised to stimulate or inhibit both plant and microbial competitiveness for soluble soil N, respectively, whereas O3 favours only microbial competitive efficiency. Understanding the consequences of elevated CO2, O3, and UV radiation for soils, especially those related to fertility, phytotoxins inputs, elements cycling, plant-microbe interactions, and decontamination of polluted sites, presents a knowledge gap for future research.

Effect of Elevated CO2, O3, and UV Radiation on Soils

PubMed Central

Rejšek, Klement; Vranová, Valerie

2014-01-01

In this work, we have attempted to review the current knowledge on the impact of elevated CO2, O3, and UV on soils. Elevated CO2 increases labile and stabile soil C pool as well as efficiency of organic pollutants rhizoremediation and phytoextraction of heavy metals. Conversely, both elevated O3 and UV radiation decrease inputs of assimilates to the rhizosphere being accompanied by inhibitory effects on decomposition processes, rhizoremediation, and heavy metals phytoextraction efficiency. Contrary to elevated CO2, O3, or UV-B decreases soil microbial biomass, metabolisable C, and soil Nt content leading to higher C/N of soil organic matter. Elevated UV-B radiation shifts soil microbial community and decreases populations of soil meso- and macrofauna via direct effect rather than by induced changes of litter quality and root exudation as in case of elevated CO2 or O3. CO2 enrichment or increased UV-B is hypothesised to stimulate or inhibit both plant and microbial competitiveness for soluble soil N, respectively, whereas O3 favours only microbial competitive efficiency. Understanding the consequences of elevated CO2, O3, and UV radiation for soils, especially those related to fertility, phytotoxins inputs, elements cycling, plant-microbe interactions, and decontamination of polluted sites, presents a knowledge gap for future research. PMID:24688424

Growth, Yield, and Nutritional Responses of Chamber-Grown Sweet Potato to Elevated Carbon Dioxide Levels Expected Across the Next 200 Years

NASA Astrophysics Data System (ADS)

Czeck, B. C.; Jahren, H.; Deenik, J. L.; Crow, S. E.; Schubert, B.; Stewart, M.

2012-12-01

Understanding the effects of increasing atmospheric carbon dioxide (CO2) concentrations on crops will be critical to assuring that sufficient food is available to the world's growing population. Previous work has shown that slightly elevated CO2 levels (CO2 = 550-700 ppm) increase the economic yield of most crops by ~33%, on average. The majority of these studies have focused on rice, wheat, and soybean; however, climate change is expected to have greatest impact on regions of the world that rely heavily on root crops, such as sweet potato (Ipomoea batatas). Sweet potato is cultivated in more than 100 developing countries; it is ranked seventh in world crop statistics and can produce more edible energy per hectare and per day than wheat, rice or cassava. In order to quantify the effect that rising CO2 levels will have on sweet potato, we grew a total of 64 sweet potato plants to maturity in large controlled growth chambers at ambient, 760, 1,140, and 1,520-ppm CO2 levels. At planting, initial measurements (of mass, length, and number of nodes) for each plant were recorded. Throughout the duration of the experiment (90 days) measurements (of stem length, and number of leaves) were recorded every 7 to 14 days. To ensure optimum growing conditions moisture content was monitored using soil tensiometers; temperature, relative humidity and CO2 concentrations were recorded every ten minutes. Half the plants were supplemented with an inorganic fertilizer and the other half with an organic fertilizer to test the effect of nutrient availability on biomass production under elevated CO2 levels. After 3 months of growth, we measured fresh and dry biomass of all above- and below-ground tissues. Results showed a substantial increase in both above- and below-ground biomass at elevated levels of CO2. For the organic treatment, a 43% increase in aboveground dry biomass at the highest CO2 concentration (1520ppm) was found; the inorganic treatment showed a 31% increase. The belowground response was appreciably greater, with a 61% increase in the organic treatment and 101% increase in the inorganic treatment. We conclude that the belowground response of root crops under elevated CO2 could have a significant impact on the food supply of developing countries as CO2 levels continue to rise. Ongoing work to quantify the nutritional status of both the leaves for animal feed and the tubers for human consumption will add insight into the quality of the enhanced biomass.

Effects of fertilizer placement on trace gas emissions from container-grown plant production

USDA-ARS?s Scientific Manuscript database

Increased trace gas emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are widely believed to be a primary cause of global warming. Agriculture is a large contributor to these emissions; however, its role in climate change is unique in that it can act as a source of trace gas ...

Effects of fertilizer placement on trace gas emissions from nursery container production

USDA-ARS?s Scientific Manuscript database

Increased trace gas emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are widely believed to be a primary cause of global warming. Agriculture is a large contributor to these emissions; however, its role in climate change is unique in that it can act as a source of trace gas ...

Forest response to elevated CO2 is conserved across a broad range of productivity

Treesearch

R. Norby; E. DeLucia; B. Gielen; C. Calfapietra; C. Giardina; J. King; J. Ledford; H. McCarthy; D. Moore; R. Ceulemans; P. De Angelis; A. C. Finzi; D. F. Karnosky; M. E. Kubiske; M. Lukac; K. S. Pregitzer; G. E. Scarascia-Mugnozza; W. Schlesinger and R. Oren.

2005-01-01

Climate change predictions derived from coupled carbon-climate models are highly dependent on assumptions about feedbacks between the biosphere and atmosphere. One critical feedback occurs if C uptake by the biosphere increases in response to the fossil-fuel driven increase in atmospheric [CO2] ("CO2 fertilization...

Causes of variation among rice models in yield response to CO2 examined with Free-Air CO2 Enrichment and growth chamber experiments.

PubMed

Hasegawa, Toshihiro; Li, Tao; Yin, Xinyou; Zhu, Yan; Boote, Kenneth; Baker, Jeffrey; Bregaglio, Simone; Buis, Samuel; Confalonieri, Roberto; Fugice, Job; Fumoto, Tamon; Gaydon, Donald; Kumar, Soora Naresh; Lafarge, Tanguy; Marcaida Iii, Manuel; Masutomi, Yuji; Nakagawa, Hiroshi; Oriol, Philippe; Ruget, Françoise; Singh, Upendra; Tang, Liang; Tao, Fulu; Wakatsuki, Hitomi; Wallach, Daniel; Wang, Yulong; Wilson, Lloyd Ted; Yang, Lianxin; Yang, Yubin; Yoshida, Hiroe; Zhang, Zhao; Zhu, Jianguo

2017-11-01

The CO 2 fertilization effect is a major source of uncertainty in crop models for future yield forecasts, but coordinated efforts to determine the mechanisms of this uncertainty have been lacking. Here, we studied causes of uncertainty among 16 crop models in predicting rice yield in response to elevated [CO 2 ] (E-[CO 2 ]) by comparison to free-air CO 2 enrichment (FACE) and chamber experiments. The model ensemble reproduced the experimental results well. However, yield prediction in response to E-[CO 2 ] varied significantly among the rice models. The variation was not random: models that overestimated at one experiment simulated greater yield enhancements at the others. The variation was not associated with model structure or magnitude of photosynthetic response to E-[CO 2 ] but was significantly associated with the predictions of leaf area. This suggests that modelled secondary effects of E-[CO 2 ] on morphological development, primarily leaf area, are the sources of model uncertainty. Rice morphological development is conservative to carbon acquisition. Uncertainty will be reduced by incorporating this conservative nature of the morphological response to E-[CO 2 ] into the models. Nitrogen levels, particularly under limited situations, make the prediction more uncertain. Improving models to account for [CO 2 ] × N interactions is necessary to better evaluate management practices under climate change.

Quantifying Direct and Indirect Effects of Elevated CO2 on Ecosystem Response

NASA Astrophysics Data System (ADS)

Fatichi, S.; Leuzinger, S.; Paschalis, A.; Donnellan-Barraclough, A.; Hovenden, M. J.; Langley, J. A.

2015-12-01

Increasing concentrations of atmospheric carbon dioxide are expected to affect carbon assimilation, evapotranspiration (ET) and ultimately plant growth. Direct leaf biochemical effects have been widely investigated, while indirect effects, although documented, are very difficult to quantify in experiments. We hypothesize that the interaction of direct and indirect effects is a possible reason for conflicting results concerning the magnitude of CO2 fertilization effects across different climates and ecosystems. A mechanistic ecohydrological model (Tethys-Chloris) is used to investigate the relative contribution of direct (through plant physiology) and indirect (via stomatal closure and thus soil moisture, and changes in Leaf Area Index, LAI) effects of elevated CO2 across a number of ecosystems. We specifically ask in which ecosystems and climate indirect effects are expected to be largest. Data and boundary conditions from flux-towers and free air CO2 enrichment (FACE) experiments are used to force the model and evaluate its performance. Numerical results suggest that indirect effects of elevated CO2, through water savings and increased LAI, are very significant and sometimes larger than direct effects. Indirect effects tend to be considerably larger in water-limited ecosystems, while direct effects correlate positively with mean air temperature. Increasing CO2 from 375 to 550 ppm causes a total effect on Net Primary Production in the order of 15 to 40% and on ET from 0 to -8%, depending on climate and ecosystem type. The total CO2 effect has a significant negative correlation with the wetness index and positive correlation with vapor pressure deficit. These results provide a more general mechanistic understanding of relatively short-term (less than 20 years) implications of elevated CO2 on ecosystem response and suggest plausible magnitudes for the expected changes.

Ammonia and greenhouse gas emissions from a subtropical wheat field under different nitrogen fertilization strategies.

PubMed

Liu, Shuai; Wang, Jim J; Tian, Zhou; Wang, Xudong; Harrison, Stephen

2017-07-01

Minimizing soil ammonia (NH 3 ) and nitrous oxide (N 2 O) emission factors (EFs) has significant implications in regional air quality and greenhouse gas (GHG) emissions besides nitrogen (N) nutrient loss. The aim of this study was to investigate the impacts of different N fertilizer treatments of conventional urea, polymer-coated urea, ammonia sulfate, urease inhibitor (NBPT, N-(n-butyl) thiophosphoric triamide)-treated urea, and nitrification inhibitor (DCD, dicyandiamide)-treated urea on emissions of NH 3 and GHGs from subtropical wheat cultivation. A field study was established in a Cancienne silt loam soil. During growth season, NH 3 emission following N fertilization was characterized using active chamber method whereas GHG emissions of N 2 O, carbon dioxide (CO 2 ), and methane (CH 4 ) were by passive chamber method. The results showed that coated urea exhibited the largest reduction (49%) in the EF of NH 3 -N followed by NBPT-treated urea (39%) and DCD-treated urea (24%) over conventional urea, whereas DCD-treated urea had the greatest suppression on N 2 O-N (87%) followed by coated urea (76%) and NBPT-treated urea (69%). Split fertilization of ammonium sulfate-urea significantly lowered both NH 3 -N and N 2 O-N EF values but split urea treatment had no impact over one-time application of urea. Both NBPT and DCD-treated urea treatments lowered CO 2 -C flux but had no effect on CH 4 -C flux. Overall, application of coated urea or urea with NPBT or DCD could be used as a mitigation strategy for reducing NH 3 and N 2 O emissions in subtropical wheat production in Southern USA. Copyright © 2017. Published by Elsevier B.V.

Potential climate change impacts on temperate forest ecosystem processes

USGS Publications Warehouse

Peters, Emily B.; Wythers, Kirk R.; Zhang, Shuxia; Bradford, John B.; Reich, Peter B.

2013-01-01

Large changes in atmospheric CO2, temperature and precipitation are predicted by 2100, yet the long-term consequences for carbon, water, and nitrogen cycling in forests are poorly understood. We applied the PnET-CN ecosystem model to compare the long-term effects of changing climate and atmospheric CO2 on productivity, evapotranspiration, runoff, and net nitrogen mineralization in current Great Lakes forest types. We used two statistically downscaled climate projections, PCM B1 (warmer and wetter) and GFDL A1FI (hotter and drier), to represent two potential future climate and atmospheric CO2 scenarios. To separate the effects of climate and CO2, we ran PnET-CN including and excluding the CO2 routine. Our results suggest that, with rising CO2 and without changes in forest type, average regional productivity could increase from 67% to 142%, changes in evapotranspiration could range from –3% to +6%, runoff could increase from 2% to 22%, and net N mineralization could increase 10% to 12%. Ecosystem responses varied geographically and by forest type. Increased productivity was almost entirely driven by CO2 fertilization effects, rather than by temperature or precipitation (model runs holding CO2 constant showed stable or declining productivity). The relative importance of edaphic and climatic spatial drivers of productivity varied over time, suggesting that productivity in Great Lakes forests may switch from being temperature to water limited by the end of the century.

Preindustrial, historical, and fertilization simulations using a global ocean carbon model with new parameterizations of iron limitation, calcification, and N 2 fixation

NASA Astrophysics Data System (ADS)

Zahariev, Konstantin; Christian, James R.; Denman, Kenneth L.

2008-04-01

The Canadian Model of Ocean Carbon (CMOC) has been developed as part of a global coupled climate carbon model. In a stand-alone integration to preindustrial equilibrium, the model ecosystem and global ocean carbon cycle are in general agreement with estimates based on observations. CMOC reproduces global mean estimates and spatial distributions of various indicators of the strength of the biological pump; the spatial distribution of the air-sea exchange of CO 2 is consistent with present-day estimates. Agreement with the observed distribution of alkalinity is good, consistent with recent estimates of the mean rain ratio that are lower than historic estimates, and with calcification occurring primarily in the lower latitudes. With anthropogenic emissions and climate forcing from a 1850-2000 climate model simulation, anthropogenic CO 2 accumulates at a similar rate and with a similar spatial distribution as estimated from observations. A hypothetical scenario for complete elimination of iron limitation generates maximal rates of uptake of atmospheric CO 2 of less than 1 PgC y -1, or about 11% of 2004 industrial emissions. Even a ‘perfect’ future of sustained fertilization would have a minor impact on atmospheric CO 2 growth. In the long term, the onset of fertilization causes the ocean to take up an additional 77 PgC after several thousand years, compared with about 84 PgC thought to have occurred during the transition into the last glacial maximum due to iron fertilization associated with increased dust deposition.

Effects of nitrogen additions on above- and belowground carbon dynamics in two tropical forests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cusack, D.; Silver, W.L.; Torn, M.S.

2011-04-15

Anthropogenic nitrogen (N) deposition is increasing rapidly in tropical regions, adding N to ecosystems that often have high background N availability. Tropical forests play an important role in the global carbon (C) cycle, yet the effects of N deposition on C cycling in these ecosystems are poorly understood. We used a field N-fertilization experiment in lower and upper elevation tropical rain forests in Puerto Rico to explore the responses of above- and belowground C pools to N addition. As expected, tree stem growth and litterfall productivity did not respond to N fertilization in either of these Nrich forests, indicating amore » lack of N limitation to net primary productivity (NPP). In contrast, soil C concentrations increased significantly with N fertilization in both forests, leading to larger C stocks in fertilized plots. However, different soil C pools responded to N fertilization differently. Labile (low density) soil C fractions and live fine roots declined with fertilization, while mineral-associated soil C increased in both forests. Decreased soil CO2 fluxes in fertilized plots were correlated with smaller labile soil C pools in the lower elevation forest (R2 = 0.65, p\\0.05), and with lower live fine root biomass in the upper elevation forest (R2 = 0.90, p\\0.05). Our results indicate that soil C storage is sensitive to N deposition in tropical forests, even where plant productivity is not N-limited. The mineral-associated soil C pool has the potential to respond relatively quickly to N additions, and can drive increases in bulk soil C stocks in tropical forests.« less

Impacts of sugarcane agriculture expansion over low-intensity cattle ranch pasture in Brazil on greenhouse gases.

PubMed

Bento, Camila Bolfarini; Filoso, Solange; Pitombo, Leonardo Machado; Cantarella, Heitor; Rossetto, Raffaella; Martinelli, Luiz Antonio; do Carmo, Janaina Braga

2018-01-15

Sugarcane is a widespread bioenergy crop in tropical regions, and the growing global demand for renewable energy in recent years has led to a dramatic expansion and intensification of sugarcane agriculture in Brazil. Currently, extensive areas of low-intensity pasture are being converted to sugarcane, while management in the remaining pasture is becoming more intensive, i.e., includes tilling and fertilizer use. In this study, we assessed how such changes in land use and management practices alter emissions of greenhouse gases (GHG) such as CO 2 , N 2 O and CH 4 by measuring in situ fluxes for one year after conversion from low-intensity pasture to conventional sugarcane agriculture and management-intensive pasture. Results show that CO 2 and N 2 O fluxes increased significantly in pasture and sugarcane with tillage, fertilizer use, or both combined. Emissions were highly variable for all GHGs, yet, cumulatively, it was clear that annual emissions in CO 2 -equivalent (CO 2 -eq) were higher in management-intense pasture and sugarcane than in unmanaged pasture. Surprisingly, tilled pasture with fertilizer (management-intensive pasture) resulted in higher CO 2 -eq emissions than conventional sugarcane. We concluded that intensification of pasture management and the conversion of pasture to sugarcane can increase the emission factor (EF) estimated for sugarcane produced in Brazil. The role of management practices and environmental conditions and the potential for reducing emissions are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nitrogen Alters Fungal Communities in Boreal Forest Soil: Implications for Carbon Cycling

NASA Astrophysics Data System (ADS)

Allison, S. D.; Treseder, K. K.

2005-12-01

One potential effect of climate change in high latitude ecosystems is to increase soil nutrient availability. In particular, greater nitrogen availability could impact decomposer communities and lead to altered rates of soil carbon cycling. Since fungi are the primary decomposers in many high-latitude ecosystems, we used molecular techniques and field surveys to test whether fungal communities and abundances differed in response to nitrogen fertilization in a boreal forest ecosystem. We predicted that fungi that degrade recalcitrant carbon would decline under nitrogen fertilization, while fungi that degrade labile carbon would increase, leading to no net change in rates of soil carbon mineralization. The molecular data showed that basidiomycete fungi dominate the active fungal community in both fertilized and unfertilized soils. However, we found that fertilization reduced peak mushroom biomass by 79%, although most of the responsive fungi were ectomycorrhizal and therefore their capacity to degrade soil carbon is uncertain. Fertilization increased the activity of the cellulose-degrading enzyme beta-glucosidase by 78%, while protease activity declined by 39% and polyphenol oxidase, a lignin-degrading enzyme, did not respond. Rates of soil respiration did not change in response to fertilization. These results suggest that increased nitrogen availability does alter the composition of the fungal community, and its potential to degrade different carbon compounds. However, these differences do not affect the total flux of CO2 from the soil, even though the contribution to CO2 respiration from different carbon pools may vary with fertilization. We conclude that in the short term, increased nitrogen availability due to climate warming or nitrogen deposition is more likely to alter the turnover of individual carbon pools rather than total carbon fluxes from the soil. Future work should determine if changes in fungal community structure and associated differences in substrate utilization will also affect total carbon fluxes over longer time scales.

Complex spatiotemporal responses of global terrestrial primary production to climate change and increasing atmospheric CO2 in the 21st century.

PubMed

Pan, Shufen; Tian, Hanqin; Dangal, Shree R S; Zhang, Chi; Yang, Jia; Tao, Bo; Ouyang, Zhiyun; Wang, Xiaoke; Lu, Chaoqun; Ren, Wei; Banger, Kamaljit; Yang, Qichun; Zhang, Bowen; Li, Xia

2014-01-01

Quantitative information on the response of global terrestrial net primary production (NPP) to climate change and increasing atmospheric CO2 is essential for climate change adaptation and mitigation in the 21st century. Using a process-based ecosystem model (the Dynamic Land Ecosystem Model, DLEM), we quantified the magnitude and spatiotemporal variations of contemporary (2000s) global NPP, and projected its potential responses to climate and CO2 changes in the 21st century under the Special Report on Emission Scenarios (SRES) A2 and B1 of Intergovernmental Panel on Climate Change (IPCC). We estimated a global terrestrial NPP of 54.6 (52.8-56.4) PgC yr(-1) as a result of multiple factors during 2000-2009. Climate change would either reduce global NPP (4.6%) under the A2 scenario or slightly enhance NPP (2.2%) under the B1 scenario during 2010-2099. In response to climate change, global NPP would first increase until surface air temperature increases by 1.5 °C (until the 2030s) and then level-off or decline after it increases by more than 1.5 °C (after the 2030s). This result supports the Copenhagen Accord Acknowledgement, which states that staying below 2 °C may not be sufficient and the need to potentially aim for staying below 1.5 °C. The CO2 fertilization effect would result in a 12%-13.9% increase in global NPP during the 21st century. The relative CO2 fertilization effect, i.e. change in NPP on per CO2 (ppm) bases, is projected to first increase quickly then level off in the 2070s and even decline by the end of the 2080s, possibly due to CO2 saturation and nutrient limitation. Terrestrial NPP responses to climate change and elevated atmospheric CO2 largely varied among biomes, with the largest increases in the tundra and boreal needleleaf deciduous forest. Compared to the low emission scenario (B1), the high emission scenario (A2) would lead to larger spatiotemporal variations in NPP, and more dramatic and counteracting impacts from climate and increasing atmospheric CO2.

Complex Spatiotemporal Responses of Global Terrestrial Primary Production to Climate Change and Increasing Atmospheric CO2 in the 21st Century

PubMed Central

Pan, Shufen; Tian, Hanqin; Dangal, Shree R. S.; Zhang, Chi; Yang, Jia; Tao, Bo; Ouyang, Zhiyun; Wang, Xiaoke; Lu, Chaoqun; Ren, Wei; Banger, Kamaljit; Yang, Qichun; Zhang, Bowen; Li, Xia

2014-01-01

Quantitative information on the response of global terrestrial net primary production (NPP) to climate change and increasing atmospheric CO2 is essential for climate change adaptation and mitigation in the 21st century. Using a process-based ecosystem model (the Dynamic Land Ecosystem Model, DLEM), we quantified the magnitude and spatiotemporal variations of contemporary (2000s) global NPP, and projected its potential responses to climate and CO2 changes in the 21st century under the Special Report on Emission Scenarios (SRES) A2 and B1 of Intergovernmental Panel on Climate Change (IPCC). We estimated a global terrestrial NPP of 54.6 (52.8–56.4) PgC yr−1 as a result of multiple factors during 2000–2009. Climate change would either reduce global NPP (4.6%) under the A2 scenario or slightly enhance NPP (2.2%) under the B1 scenario during 2010–2099. In response to climate change, global NPP would first increase until surface air temperature increases by 1.5°C (until the 2030s) and then level-off or decline after it increases by more than 1.5°C (after the 2030s). This result supports the Copenhagen Accord Acknowledgement, which states that staying below 2°C may not be sufficient and the need to potentially aim for staying below 1.5°C. The CO2 fertilization effect would result in a 12%–13.9% increase in global NPP during the 21st century. The relative CO2 fertilization effect, i.e. change in NPP on per CO2 (ppm) bases, is projected to first increase quickly then level off in the 2070s and even decline by the end of the 2080s, possibly due to CO2 saturation and nutrient limitation. Terrestrial NPP responses to climate change and elevated atmospheric CO2 largely varied among biomes, with the largest increases in the tundra and boreal needleleaf deciduous forest. Compared to the low emission scenario (B1), the high emission scenario (A2) would lead to larger spatiotemporal variations in NPP, and more dramatic and counteracting impacts from climate and increasing atmospheric CO2. PMID:25401492

Effects of climate change, CO2 and O3 on wheat productivity in Eastern China, singly and in combination

NASA Astrophysics Data System (ADS)

Tao, Fulu; Feng, Zhaozhong; Tang, Haoye; Chen, Yi; Kobayashi, Kazuhiko

2017-03-01

Air pollution and climate change are increasing threats to agricultural production and food security. Extensive studies have focused on the effect of climate change, but the interactive effects of multiple global change factors are poorly understood. Here, we incorporate the interactions between climate change, carbon dioxide (CO2) and ozone (O3) into an eco-physiological mechanistic model based on three years of O3 Free-Air Concentration Elevation (O3-FACE) experiments. We then investigate the effects of climate change, elevated CO2 concentration ([CO2]) and rising O3 concentration ([O3]) on wheat growth and productivity in eastern China in 1996-2005 (2000s) and 2016-2025 (2020s) under two climate change scenarios, singly and in combination. We find the interactive effects of climate change, CO2 and O3 on wheat productivity have spatially explicit patterns; the effect of climate change dominates the general pattern, which is however subject to the large uncertainties of climate change scenarios. Wheat productivity is estimated to increase by 2.8-9.0% due to elevated [CO2] however decline by 2.8-11.7% due to rising [O3] in the 2020s, relative to the 2000s. The combined effects of CO2 and O3 are less than that of O3 only, on average by 4.6-5.2%, however with O3 damage outweighing CO2 benefit in most of the region. This study demonstrates a more biologically meaningful and appropriate approach for assessing the interactive effects of climate change, CO2 and O3 on crop growth and productivity. Our findings promote the understanding on the interactive effects of multiple global change factors across contrasting climate conditions, cast doubt on the potential of CO2 fertilization effect in offsetting possible negative effect of climate change on crop productivity as suggested by many previous studies.

Effect of metal oxides on the stabilization of soil organic matter

NASA Astrophysics Data System (ADS)

Stelmach, Wioleta

2017-04-01

Soil organic matter (SOM) is protected from decomposition by three mechanisms: 1) biochemical stabilization through the accumulation of recalcitrant SOM compounds, 2) physical stabilization, i.e. spatial inaccessibility of SOM for microbes, and 3) chemical protection of SOM through intimate interaction with minerals and metal oxides. The latter mechanisms suggest that added organic substances (i.e. post-fermentation sludge) can be stabilized by metal oxides to increase C sequestration in soil. The aim of this study was to determine the effects of Fe2O3 - one of the dominant metal oxides in soil - on the sequestration of post-fermentation sludge C in soil by separately tracing the decomposition of sludge and of SOM to carbon dioxide (CO2). To determine changes in SOM turnover after the addition of post-fermentation sludge without/with Fe2O3, the isotopic signatures of both C sources (SOM and post-fermentation sludge) were used. Using differences in the 13C natural abundance of the soil (C3 originated, δ13C = -26) and the post-fermentation sludge (C4 originated, δ13C = -18), the CO2 fluxes arising from both C sources were tracked. Addition of post-fermentation sludge to the soil increased the CO2 production by 30% compared to soil without sludge. δ13C analysis of the total CO2 efflux revealed that post-fermentation sludge decreased SOM decomposition. Fe2O3 slightly suppressed sludge decomposition, and therefore increased C sequestration in soil. Only 30% of the post-fermentation sludge had been mineralized after one month of incubation in the soil. The collective results of my study reveal that application of post-fermentation sludge suppresses SOM decomposition, suggesting its use as a fertilizer could positively influence long-term soil quality. Finally, the success of the 13C natural abundance microcosm labeling approach in my study supports its use as an effective method of analyzing the effects of various fertilization techniques on soil nutrient retention. Such results were only possible by partitioning of the total CO2.

Changing concentrations of CO, CH(4), C(5)H(8), CH(3)Br, CH(3)I, and dimethyl sulfide during the Southern Ocean Iron Enrichment Experiments.

PubMed

Wingenter, Oliver W; Haase, Karl B; Strutton, Peter; Friederich, Gernot; Meinardi, Simone; Blake, Donald R; Rowland, F Sherwood

2004-06-08

Oceanic iron (Fe) fertilization experiments have advanced the understanding of how Fe regulates biological productivity and air-sea carbon dioxide (CO(2)) exchange. However, little is known about the production and consumption of halocarbons and other gases as a result of Fe addition. Besides metabolizing inorganic carbon, marine microorganisms produce and consume many other trace gases. Several of these gases, which individually impact global climate, stratospheric ozone concentration, or local photochemistry, have not been previously quantified during an Fe-enrichment experiment. We describe results for selected dissolved trace gases including methane (CH(4)), isoprene (C(5)H(8)), methyl bromide (CH(3)Br), dimethyl sulfide, and oxygen (O(2)), which increased subsequent to Fe fertilization, and the associated decreases in concentrations of carbon monoxide (CO), methyl iodide (CH(3)I), and CO(2) observed during the Southern Ocean Iron Enrichment Experiments.

Increased Activity of Rhizosphere and Hyphosphere Enzymes under Elevated CO2 in a Loblolly Pine Stand

NASA Astrophysics Data System (ADS)

Meier, I.; Phillips, R.

2012-12-01

The stimulatory effect of elevated atmospheric CO2 under global climate change on forest productivity has been predicted to decrease over time as pools of available N in soil become depleted, but empirical support for such progressive N limitation has been lacking. Increased N acquisition from soil depleted in inorganic nitrogen requires stimulation of the microbial processing of organic N, possibly through increasing C supply to soil by plant roots or mycorrhizal hyphae. Increases in (mycorr)rhizosphere C fluxes could stimulate microbes to produce extra-cellular enzymes that release N from SOM, feeding back from soil microsites to ecosystem-scale processes. We investigated the influence of elevated CO2 on root exudation and soil enzyme activity at the Duke Forest FACE site, USA, where loblolly pine (Pinus taeda L.) stands have been exposed to elevated CO2 for 14 years and N fertilization for five years. In each plot, root boxes containing acetate windows were installed in 2008. Two years after installation, we collected soils adjacent to root tips (the rhizosphere), hyphal tips (the hyphosphere) and bulk soil. We measured in situ root exudation rates from intact pine roots. Study objectives were to analyze (i) the influence of atmospheric CO2 on root exudation and extra-cellular enzyme activities, (ii) the influence of soil N availability in regulating these activities, and (iii) the relationship between the activities of enzymes involved in N cycling in soils and gross N transformations at soil microsites. Elevated atmospheric CO2 significantly increased the activity of β-1-4-N-acetylglucosaminidase (NAG) in the rhizosphere by almost 2.5 times (39 to 95 nmol h-1 g-1), and 1.6fold in the hyphosphere relative to ambient plots. NAG is an enzyme involved in the degradation of chitin from the cell walls of soil organisms, releasing absorbable forms of nitrogen. The activity of peroxidase, which degrades aromatic C compounds of SOM, increased significantly in the hyphosphere of stands exposed to elevated CO2. Nitrogen fertilization diminished this effect of elevated CO2 on enzyme activities at microsites. Our results show that the metabolism of microbial communities is shifted to the decomposition of organic N under elevated atmospheric CO2, presumably stimulated by N limitation and increased root C exudation.

Heat stress during in vitro fertilization decreases fertilization success by disrupting anti-polyspermy systems of the oocytes.

PubMed

Sakatani, Miki; Yamanaka, Kenichi; Balboula, Ahmed Z; Takenouchi, Naoki; Takahashi, Masashi

2015-01-01

Low pregnancy rates during the summer are due, in part, to reduced fertilization. Given that elevated temperature is associated with this season, we investigated the effect of heat stress during fertilization using an in vitro model. Three experiments were performed to determine the mechanism by which exposure to elevated temperature disrupts fertilization. Oocytes were fertilized for 6 hr at 38.5°C or 41.0°C or 40.0°C with non-pre-incubated sperm, or for 6 hr at 38.5°C with sperm that had been pre-incubated at 38.5°C or 41.0°C for 4 hr. In each experiment, zygotes were cultured at 38.5°C in 5% CO(2) and 5% O(2). Rates of cleavage and blasocyst formation were reduced when fertilization occurs at elevated temperatures. The percent of sperm classified as alive, using fluorescein diacetate labeling, was decreased by pre-incubation and fertilization at 40.0°C. Although no difference was observed in sperm penetration rate, polyspermy tended to be increased by heat stress during fertilization. The zona pellucidae of zygotes formed following fertilization at 40.0°C for 6 hr were more sensitive to digestion with pronase. Furthermore, these zygotes exhibited higher hydrogen peroxide levels, measured by 2,7-dihydrodichlorofluorescein diacetate staining, and showed increased transcript abundance for HSPA1A, a gene involved in the heat-shock response, but decreased transcript abundance for UCHL1, a gene involved in preventing polyspermy. Results indicate that heat stress during fertilization is lethal to sperm, and causes oxidative stress, altered transcript abundance, and a defective block to polyspermy in the zygote. Thus, an increase in polyspermy is likely one cause of the reduced competency of zygotes fertilized under elevated temperatures to develop to the blastocyst stage. © 2014 Wiley Periodicals, Inc.

Comparison of greenhouse gas emissions from rice paddy fields under different nitrogen fertilization loads in Chongming Island, Eastern China.

PubMed

Zhang, Xianxian; Yin, Shan; Li, Yinsheng; Zhuang, Honglei; Li, Changsheng; Liu, Chunjiang

2014-02-15

Rice is one of the major crops of southern China and Southeast Asia. Rice paddies are one of the largest agricultural greenhouse gas (GHG) sources in this region because of the application of large quantities of nitrogen (N) fertilizers to the plants. In particular, the production of methane (CH4) is a concern. Investigating a reasonable amount of fertilizers to apply to plants is essential to maintaining high yields while reducing GHG emissions. In this study, three levels of fertilizer application [high (300 kg N/ha), moderate (210 kg N/ha), and low (150 kg N/ha)] were designed to examine the effects of variation in N fertilizer application rate on carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions from the paddy fields in Chongming Island, Shanghai, China. The high level (300 kg N/ha) represented the typical practice adopted by the local farmers in the area. Maximum amounts of CH4 and N2O fluxes were observed upon high-level fertilizer application in the plots. Cumulative N2O emissions of 23.09, 40.10, and 71.08 mg N2O/m(2) were observed over the growing season in 2011 under the low-, moderate-, and high-level applications plots, respectively. The field data also indicated that soil temperatures at 5 and 10 cm soil depths significantly affected soil respiration; the relationship between Rs and soil temperature in this study could be described by an exponential model. Our study showed that reducing the high rate of fertilizer application is a feasible way of attenuating the global-warming potential while maintaining the optimum yield for the studied paddy fields. Copyright © 2013 Elsevier B.V. All rights reserved.

Investigating the relative importance of nitrogen deposition on the terrestrial carbon sink in recent decades

NASA Astrophysics Data System (ADS)

O'Sullivan, M.; Buermann, W.; Spracklen, D. V.; Gloor, E. U.; Arnold, S.

2017-12-01

The global terrestrial carbon sink has increased since the start of this century at a time of rapidly growing carbon dioxide emissions from fossil fuel burning. Here we test the hypothesis that these parallel increases in fossil fuel burning and terrestrial sink are causally linked via increases in atmospheric CO2 and nitrogen deposition (and carbon-nitrogen interaction). Using the dynamic global vegetation model CLM4.5-BGC, we performed factorial analyses, separating the effects of individual drivers to changes in carbon fluxes and sinks. Globally, we found that increases in nitrogen deposition from 1900 to 2016 led to an additional 32 PgC stored. 40% of this increase could be attributed to East Asia and Europe alone, with North America also having a significant contribution. The global, post-2000 anthropogenic nitrogen deposition effect on terrestrial carbon uptake was 0.7 PgC/yr (20% of the total sink). Comparing the past decade (2005-2016) to the previous (1990-2005), regionally, we find nitrogen deposition to be an important driver of changes in net carbon uptake. In East Asia, increases in nitrogen deposition contributed 26% of the total increase in carbon uptake, with direct CO2 fertilization contributing 67%, and the synergistic carbon-nitrogen effect explaining 7% of the sink. Conversely, declining nitrogen deposition rates over North America contributed negatively (-35%) to the carbon sink, with a near zero contribution from the synergistic effect. At global scale, however, our findings suggest that changes in nitrogen deposition (both direct and via increasing the efficiency of the CO2 fertilization effect) played only a minor role in the enhanced plant carbon uptake and sink activity during the most recent decade. This finding is due to regional compensations but also suggesting that other factors (direct CO2, climate, land use change) may have been more important drivers.

Future Climate CO2 Levels Mitigate Stress Impact on Plants: Increased Defense or Decreased Challenge?

PubMed Central

AbdElgawad, Hamada; Zinta, Gaurav; Beemster, Gerrit T. S.; Janssens, Ivan A.; Asard, Han

2016-01-01

Elevated atmospheric CO2 can stimulate plant growth by providing additional C (fertilization effect), and is observed to mitigate abiotic stress impact. Although, the mechanisms underlying the stress mitigating effect are not yet clear, increased antioxidant defenses, have been held primarily responsible (antioxidant hypothesis). A systematic literature analysis, including “all” papers [Web of Science (WoS)-cited], addressing elevated CO2 effects on abiotic stress responses and antioxidants (105 papers), confirms the frequent occurrence of the stress mitigation effect. However, it also demonstrates that, in stress conditions, elevated CO2 is reported to increase antioxidants, only in about 22% of the observations (e.g., for polyphenols, peroxidases, superoxide dismutase, monodehydroascorbate reductase). In most observations, under stress and elevated CO2 the levels of key antioxidants and antioxidant enzymes are reported to remain unchanged (50%, e.g., ascorbate peroxidase, catalase, ascorbate), or even decreased (28%, e.g., glutathione peroxidase). Moreover, increases in antioxidants are not specific for a species group, growth facility, or stress type. It seems therefore unlikely that increased antioxidant defense is the major mechanism underlying CO2-mediated stress impact mitigation. Alternative processes, probably decreasing the oxidative challenge by reducing ROS production (e.g., photorespiration), are therefore likely to play important roles in elevated CO2 (relaxation hypothesis). Such parameters are however rarely investigated in connection with abiotic stress relief. Understanding the effect of elevated CO2 on plant growth and stress responses is imperative to understand the impact of climate changes on plant productivity. PMID:27200030

Quantifying root lateral distribution and turnover using pine trees with a distinct stable carbon isotope signature

Treesearch

Kurt H. Johnsen; Chris A. Maier; Lance W. Kress

2005-01-01

In order to help assess spatial competition for below-ground resources, we quantified the effects of fertilization on root biomass quantity and lateral root distribution of midrotation Pinus taeda trees. Open-top chambers exposed trees to ambient or ambient plus 200 µmol mol-1 atmospheric CO2...

Recent pause in the growth rate of atmospheric CO2 due to enhanced terrestrial carbon uptake

PubMed Central

Keenan, Trevor F; Prentice, I. Colin; Canadell, Josep G; Williams, Christopher A; Wang, Han; Raupach, Michael; Collatz, G. James

2016-01-01

Terrestrial ecosystems play a significant role in the global carbon cycle and offset a large fraction of anthropogenic CO2 emissions. The terrestrial carbon sink is increasing, yet the mechanisms responsible for its enhancement, and implications for the growth rate of atmospheric CO2, remain unclear. Here using global carbon budget estimates, ground, atmospheric and satellite observations, and multiple global vegetation models, we report a recent pause in the growth rate of atmospheric CO2, and a decline in the fraction of anthropogenic emissions that remain in the atmosphere, despite increasing anthropogenic emissions. We attribute the observed decline to increases in the terrestrial sink during the past decade, associated with the effects of rising atmospheric CO2 on vegetation and the slowdown in the rate of warming on global respiration. The pause in the atmospheric CO2 growth rate provides further evidence of the roles of CO2 fertilization and warming-induced respiration, and highlights the need to protect both existing carbon stocks and regions, where the sink is growing rapidly. PMID:27824333

Recent pause in the growth rate of atmospheric CO 2 due to enhanced terrestrial carbon uptake

DOE PAGES

Keenan, Trevor F.; Prentice, I. Colin; Canadell, Josep G.; ...

2016-11-08

Terrestrial ecosystems play a significant role in the global carbon cycle and offset a large fraction of anthropogenic CO 2 emissions. The terrestrial carbon sink is increasing, yet the mechanisms responsible for its enhancement, and implications for the growth rate of atmospheric CO 2, remain unclear. Here using global carbon budget estimates, ground, atmospheric and satellite observations, and multiple global vegetation models, we report a recent pause in the growth rate of atmospheric CO 2, and a decline in the fraction of anthropogenic emissions that remain in the atmosphere, despite increasing anthropogenic emissions. We also attribute the observed decline tomore » increases in the terrestrial sink during the past decade, associated with the effects of rising atmospheric CO 2 on vegetation and the slowdown in the rate of warming on global respiration. Furthermore, the pause in the atmospheric CO 2 growth rate provides further evidence of the roles of CO 2 fertilization and warming-induced respiration, and highlights the need to protect both existing carbon stocks and regions, where the sink is growing rapidly.« less

Recent pause in the growth rate of atmospheric CO 2 due to enhanced terrestrial carbon uptake

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keenan, Trevor F.; Prentice, I. Colin; Canadell, Josep G.

Terrestrial ecosystems play a significant role in the global carbon cycle and offset a large fraction of anthropogenic CO 2 emissions. The terrestrial carbon sink is increasing, yet the mechanisms responsible for its enhancement, and implications for the growth rate of atmospheric CO 2, remain unclear. Here using global carbon budget estimates, ground, atmospheric and satellite observations, and multiple global vegetation models, we report a recent pause in the growth rate of atmospheric CO 2, and a decline in the fraction of anthropogenic emissions that remain in the atmosphere, despite increasing anthropogenic emissions. We also attribute the observed decline tomore » increases in the terrestrial sink during the past decade, associated with the effects of rising atmospheric CO 2 on vegetation and the slowdown in the rate of warming on global respiration. Furthermore, the pause in the atmospheric CO 2 growth rate provides further evidence of the roles of CO 2 fertilization and warming-induced respiration, and highlights the need to protect both existing carbon stocks and regions, where the sink is growing rapidly.« less

Field-based estimates of global warming potential in bioenergy systems of Hawaii: Crop choice and deficit irrigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pawlowski, Meghan N.; Crow, Susan E.; Meki, Manyowa N.

Replacing fossil fuel with biofuel is environmentally viable from a climate change perspective only if the net greenhouse gas (GHG) footprint of the system is reduced. The effects of replacing annual arable crops with perennial bioenergy feedstocks on net GHG production and soil carbon (C) stock are critical to the system-level balance. Here, we compared GHG flux, crop yield, root biomass, and soil C stock under two potential tropical, perennial grass biofuel feedstocks: conventional sugarcane and ratoon-harvested, zero-tillage napiergrass. Evaluations were conducted at two irrigation levels, 100% of plantation application and at a 50% deficit. Peaks and troughs of GHGmore » emission followed agronomic events such as ratoon harvest of napiergrass and fertilization. Yet, net GHG flux was dominated by carbon dioxide (CO 2), as methane was oxidized and nitrous oxide (N 2O) emission was very low even following fertilization. High N 2O fluxes that frequently negate other greenhouse gas benefits that come from replacing fossil fuels with agronomic forms of bioenergy were mitigated by efficient water and fertilizer management, including direct injection of fertilizer into buried irrigation lines. From soil intensively cultivated for a century in sugarcane, soil C stock and root biomass increased rapidly following cultivation in grasses selected for robust root systems and drought tolerance. The net soil C increase over the two-year crop cycle was three-fold greater than the annualized soil surface CO 2 flux. Furthermore, deficit irrigation reduced yield, but increased soil C accumulation as proportionately more photosynthetic resources were allocated below ground. In the first two years of cultivation napier grass did not increase net greenhouse warming potential (GWP) compared to sugarcane, and has the advantage of multiple ratoon harvests per year and less negative effects of deficit irrigation to yield.« less

Field-based estimates of global warming potential in bioenergy systems of Hawaii: Crop choice and deficit irrigation

DOE PAGES

Pawlowski, Meghan N.; Crow, Susan E.; Meki, Manyowa N.; ...

2017-01-04

Replacing fossil fuel with biofuel is environmentally viable from a climate change perspective only if the net greenhouse gas (GHG) footprint of the system is reduced. The effects of replacing annual arable crops with perennial bioenergy feedstocks on net GHG production and soil carbon (C) stock are critical to the system-level balance. Here, we compared GHG flux, crop yield, root biomass, and soil C stock under two potential tropical, perennial grass biofuel feedstocks: conventional sugarcane and ratoon-harvested, zero-tillage napiergrass. Evaluations were conducted at two irrigation levels, 100% of plantation application and at a 50% deficit. Peaks and troughs of GHGmore » emission followed agronomic events such as ratoon harvest of napiergrass and fertilization. Yet, net GHG flux was dominated by carbon dioxide (CO 2), as methane was oxidized and nitrous oxide (N 2O) emission was very low even following fertilization. High N 2O fluxes that frequently negate other greenhouse gas benefits that come from replacing fossil fuels with agronomic forms of bioenergy were mitigated by efficient water and fertilizer management, including direct injection of fertilizer into buried irrigation lines. From soil intensively cultivated for a century in sugarcane, soil C stock and root biomass increased rapidly following cultivation in grasses selected for robust root systems and drought tolerance. The net soil C increase over the two-year crop cycle was three-fold greater than the annualized soil surface CO 2 flux. Furthermore, deficit irrigation reduced yield, but increased soil C accumulation as proportionately more photosynthetic resources were allocated below ground. In the first two years of cultivation napier grass did not increase net greenhouse warming potential (GWP) compared to sugarcane, and has the advantage of multiple ratoon harvests per year and less negative effects of deficit irrigation to yield.« less

Soil CO2 flux in response to elevated atmospheric CO2 and nitrogen fertilization: patterns and methods

Treesearch

James M. Vose; Katherine J. Elliott; D.W. Johnson

1995-01-01

The evolution of carbon dioxide (CO2) from soils is due to the metabolic activity of roots, mycorrhizae, and soil micro- and macro-organisms. Although precise estimates of carbon (C) recycled to the atmosphere from belowground sources are unavailable, Musselman and Fox (1991) propose that the belowground contribution exceeds 100 Pg y-1...

Responses of beech and spruce foliage to elevated carbon dioxide, increased nitrogen deposition and soil type

PubMed Central

Günthardt-Goerg, Madeleine Silvia; Vollenweider, Pierre

2015-01-01

Although enhanced carbon fixation by forest trees may contribute significantly to mitigating an increase in atmospheric carbon dioxide (CO2), capacities for this vary greatly among different tree species and locations. This study compared reactions in the foliage of a deciduous and a coniferous tree species (important central European trees, beech and spruce) to an elevated supply of CO2 and evaluated the importance of the soil type and increased nitrogen deposition on foliar nutrient concentrations and cellular stress reactions. During a period of 4 years, beech (represented by trees from four different regions) and spruce saplings (eight regions), planted together on either acidic or calcareous forest soil in the experimental model ecosystem chambers, were exposed to single and combined treatments consisting of elevated carbon dioxide (+CO2, 590 versus 374 μL L−1) and elevated wet nitrogen deposition (+ND, 50 versus 5 kg ha−1 a−1). Leaf size and foliage mass of spruce were increased by +CO2 on both soil types, but those of beech by +ND on the calcareous soil only. The magnitude of the effects varied among the tree origins in both species. Moreover, the concentration of secondary compounds (proanthocyanidins) and the leaf mass per area, as a consequence of cell wall thickening, were also increased and formed important carbon sinks within the foliage. Although the species elemental concentrations differed in their response to CO2 fertilization, the +CO2 treatment effect was weakened by an acceleration of cell senescence in both species, as shown by a decrease in photosynthetic pigment and nitrogen concentration, discolouration and stress symptoms at the cell level; the latter were stronger in beech than spruce. Hence, young trees belonging to a species with different ecological niches can show contrasting responses in their foliage size, but similar responses at the cell level, upon exposure to elevated levels of CO2. The soil type and its nutrient supply largely determined the fertilization gain, especially in the case of beech trees with a narrow ecological amplitude. PMID:26092041

Photosynthesis sensitivity to climate change in land surface models

NASA Astrophysics Data System (ADS)

Manrique-Sunen, Andrea; Black, Emily; Verhoef, Anne; Balsamo, Gianpaolo

2016-04-01

Accurate representation of vegetation processes within land surface models is key to reproducing surface carbon, water and energy fluxes. Photosynthesis determines the amount of CO2 fixated by plants as well as the water lost in transpiration through the stomata. Photosynthesis is calculated in land surface models using empirical equations based on plant physiological research. It is assumed that CO2 assimilation is either CO2 -limited, radiation -limited ; and in some models export-limited (the speed at which the products of photosynthesis are used by the plant) . Increased levels of atmospheric CO2 concentration tend to enhance photosynthetic activity, but the effectiveness of this fertilization effect is regulated by environmental conditions and the limiting factor in the photosynthesis reaction. The photosynthesis schemes at the 'leaf level' used by land surface models JULES and CTESSEL have been evaluated against field photosynthesis observations. Also, the response of photosynthesis to radiation, atmospheric CO2 and temperature has been analysed for each model, as this is key to understanding the vegetation response that climate models using these schemes are able to reproduce. Particular emphasis is put on the limiting factor as conditions vary. It is found that while at present day CO2 concentrations export-limitation is only relevant at low temperatures, as CO2 levels rise it becomes an increasingly important restriction on photosynthesis.

Growing Azolla to produce sustainable protein feed: the effect of differing species and CO2 concentrations on biomass productivity and chemical composition.

PubMed

Brouwer, Paul; Schluepmann, Henriette; Nierop, Klaas Gj; Elderson, Janneke; Bijl, Peter K; van der Meer, Ingrid; de Visser, Willem; Reichart, Gert-Jan; Smeekens, Sjef; van der Werf, Adrie

2018-03-24

Since available arable land is limited and nitrogen fertilizers pollute the environment, cropping systems ought to be developed that do not rely on them. Here we investigate the rapidly growing, N 2 -fixing Azolla/Nostoc symbiosis for its potential productivity and chemical composition to determine its potential as protein feed. In a small production system, cultures of Azolla pinnata and Azolla filiculoides were continuously harvested for over 100 days, yielding an average productivity of 90.0-97.2 kg dry weight (DW) ha -1  d -1 . Under ambient CO 2 levels, N 2 fixation by the fern's cyanobacterial symbionts accounted for all nitrogen in the biomass. Proteins made up 176-208 g kg -1 DW (4.9 × total nitrogen), depending on species and CO 2 treatment, and contained more essential amino acids than protein from soybean. Elevated atmospheric CO 2 concentrations (800 ppm) significantly boosted biomass production by 36-47%, without decreasing protein content. Choice of species and CO 2 concentrations further affected the biomass content of lipids (79-100 g kg -1 DW) and (poly)phenols (21-69 g kg -1 DW). By continuous harvesting, high protein yields can be obtained from Azolla cultures, without the need for nitrogen fertilization. High levels of (poly)phenols likely contribute to limitations in the inclusion rate of Azolla in animal diets and need further investigation. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Elevated atmospheric CO2 negatively impacts photosynthesis through radiative forcing and physiology-mediated climate feedback

NASA Astrophysics Data System (ADS)

Zhu, Peng; Zhuang, Qianlai; Ciais, Philippe; Welp, Lisa; Li, Wenyu; Xin, Qinchuan

2017-02-01

Increasing atmospheric CO2 affects photosynthesis involving directly increasing leaf carboxylation rates, stomatal closure, and climatic effects. The direct effects are generally thought to be positive leading to increased photosynthesis, while its climatic effects can be regionally positive or negative. These effects are usually considered to be independent from each other, but they are in fact coupled through interactions between land surface exchanges of gases and heat and the physical climate system. In particular, stomatal closure reduces evapotranspiration and increases sensible heat emissions from ecosystems, leading to decreased atmospheric moisture and precipitation and local warming. We use a coupled earth system model to attribute the influence of the increase in CO2 on gross primary productivity (GPP) during the period of 1930-2011. In our model, CO2 radiative effects cause climate change that has only a negligible effect on global GPP (a reduction of 0.9 ± 2% during the last 80 years) because of opposite responses between tropical and northern biomes. On the other hand, CO2 physiological effects on GPP are both positive, by increased carboxylation rates and water use efficiency (7.1 ± 0.48% increase), and negative, by vegetation-climate feedback reducing precipitation, as a consequence of decreased transpiration and increased sensible heat in areas without water limitation (2.7 ± 1.76% reduction).When considering the coupled atmosphere-vegetation system, negative climate feedback on photosynthesis and plant growth due to the current level of CO2 opposes 29-38% of the gains from direct fertilization effects.

Agricultural green revolution as a driver of increasing atmospheric CO2 seasonal amplitude

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Ning; Zhao, Fang; Collatz, George

The atmospheric carbon dioxide (CO2) record displays a prominent seasonal cycle that arises mainly from changes in vegetation growth and the corresponding CO2 uptake during the boreal spring and summer growing seasons and CO2 release during the autumn and winter seasons. The CO2 seasonal amplitude has increased over the past five decades, suggesting an increase in Northern Hemisphere biospheric activity. It has been proposed that vegetation growth may have been stimulated by higher concentrations of CO2 as well as by warming in recent decades, but such mechanisms have been unable to explain the full range and magnitude of the observedmore » increase in CO2 seasonal amplitude. Here we suggest that the intensification of agriculture (the Green Revolution, in which much greater crop yield per unit area was achieved by hybridization, irrigation and fertilization) during the past five decades is a driver of changes in the seasonal characteristics of the global carbon cycle. Our analysis of CO2 data and atmospheric inversions shows a robust 15 per cent long-term increase in CO2 seasonal amplitude from 1961 to 2010, punctuated by large decadal and interannual variations. Using a terrestrial carbon cycle model that takes into account high-yield cultivars, fertilizer use and irrigation, we find that the long-term increase in CO2 seasonal amplitude arises from two major regions: the mid-latitude cropland between 256N and 606N and the high-latitude natural vegetation between 506N and 706 N. The long-term trend of seasonal amplitude increase is 0.311 ± 0.027 percent per year, of which sensitivity experiments attribute 45, 29 and 26 per cent to land-use change, climate variability and change, and increased productivity due to CO2 fertilization, respectively. Vegetation growth was earlier by one to two weeks, as measured by the mid-point of vegetation carbon uptake, and took up 0.5 petagrams more carbon in July, the height of the growing season, during 2001–2010 than in 1961–1970, suggesting that human land use and management contribute to seasonal changes in the CO2 exchange between the biosphere and the atmosphere.« less

Synthesis of a novel slow-release potassium fertilizer from modified Pidgeon magnesium slag by potassium carbonate.

PubMed

Li, Yongling; Cheng, Fangqin

2016-08-01

A novel slow-release potassium fertilizer (SPF) was synthesized using Pidgeon magnesium slag (PMS) and potassium carbonate, which could minimize fertilizer nutrient loss and PMS disposal problems. Orthogonal experiments were conducted to determine the optimum conditions for synthesis. The potassium (K)-bearing compounds of SPF existed mainly in the form of crystalline phases Ca1.197K0.166SiO4, K2MgSiO4, and K4CaSi3O9, and in the noncrystalline phase. The active silicon content of SPF was 2.09 times as much as that of magnesium slag, and the slow-release character of SPF met the requirement for partly slow-release fertilizer in the national standard (GB/T23348-2009). The best models for describing the K release kinetics in water and 2% citric acid were the Elovich model and the first-order model, respectively. The heavy metal contents of SPF conformed to the national standard for organic-inorganic compound fertilizers, and the leaching mass concentrations of heavy metals and Fluorine were far lower than the limit values of the identification standard for hazardous waste identification for extraction toxicity (GB5085.3-2007), and also met the class II quality standard for ground water. The environmental risk of SPF is therefore very low, but because SPF is alkaline, its effect on soil pH should be taken into account. PMS is the solid waste resulting from the production of magnesium metal by Pidgeon's reduction process. Utilization of PMS in the high-technology and high-value areas may promote the high-efficiency development of worldwide collection metallic magnesium industry and contribute to the reduction of emissions of fine dust to air. This paper presents one of the new techniques in the use of PMS as a slow-release fertilizer by adding K2CO3. The product can serve as a very cost-effective and reliable artificial fertilizer.

Photosynthetic and stomatal acclimation to elevated CO{sub 2} depends on soil type in Quercus prinus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunce, J.A.

1995-06-01

Quercus prinus (L.) seedlings grown outdoors at ambient and elevated (ambient + 350 ppm) CO{sub 2} with a fertile soil had no photosynthetic acclimation to elevated CO{sub 2} and no stomatal response to growth or measurement CO{sub 2}. In contrast, seedlings grown with soil collected from a Q. prinus stand had photosynthetic and stomatal acclimation, and stomatal conductance was sensitive to measurement CO{sub 2}. In plants grown with the native soil, light-saturated stomatal conductance measured at the growth CO{sub 2} was reduced by 54% at elevated CO{sub 2}, compared to the short-term reduction of 36%. Photosynthetic acclimation in plants grownmore » with the native soil reduced the stimulation of light-saturated photosynthesis at elevated CO{sub 2} from a factor of 1.9 to a factor of 1.3. In contrast to the dependence of photosynthetic and stomatal acclimation on soil type, the response of leaf respiration to elevated CO{sub 2} was the same for both soils. Respiration of leaves was reduced in the elevated CO{sub 2} treatment by 41 % on a leaf area basis. However, this effect was immediately reversible by altering the measurement CO{sub 2}, indicating that no acclimation of respiration occurred.« less

The greenhouse gas balance of European grasslands.

PubMed

Chang, Jinfeng; Ciais, Philippe; Viovy, Nicolas; Vuichard, Nicolas; Sultan, Benjamin; Soussana, Jean-François

2015-10-01

The greenhouse gas (GHG) balance of European grasslands (EU-28 plus Norway and Switzerland), including CO2 , CH4 and N2 O, is estimated using the new process-based biogeochemical model ORCHIDEE-GM over the period 1961-2010. The model includes the following: (1) a mechanistic representation of the spatial distribution of management practice; (2) management intensity, going from intensively to extensively managed; (3) gridded simulation of the carbon balance at ecosystem and farm scale; and (4) gridded simulation of N2 O and CH4 emissions by fertilized grassland soils and livestock. The external drivers of the model are changing animal numbers, nitrogen fertilization and deposition, land-use change, and variable CO2 and climate. The carbon balance of European grassland (NBP) is estimated to be a net sink of 15 ± 7 g C m(-2 ) year(-1) during 1961-2010, equivalent to a 50-year continental cumulative soil carbon sequestration of 1.0 ± 0.4 Pg C. At the farm scale, which includes both ecosystem CO2 fluxes and CO2 emissions from the digestion of harvested forage, the net C balance is roughly halved, down to a small sink, or nearly neutral flux of 8 g C m(-2 ) year(-1) . Adding CH4 and N2 O emissions to net ecosystem exchange to define the ecosystem-scale GHG balance, we found that grasslands remain a net GHG sink of 19 ± 10 g C-CO2 equiv. m(-2 ) year(-1) , because the CO2 sink offsets N2 O and grazing animal CH4 emissions. However, when considering the farm scale, the GHG balance (NGB) becomes a net GHG source of -50 g C-CO2 equiv. m(-2 ) year(-1) . ORCHIDEE-GM simulated an increase in European grassland NBP during the last five decades. This enhanced NBP reflects the combination of a positive trend of net primary production due to CO2 , climate and nitrogen fertilization and the diminishing requirement for grass forage due to the Europe-wide reduction in livestock numbers. © 2015 John Wiley & Sons Ltd.

Ecosystem-based greenhouse budgets in oil palm plantations differ with plantation age

NASA Astrophysics Data System (ADS)

Meijide, Ana; Hassler, Evelyn; Corre, Marife D.; June, Tania; Veldkamp, Edzo; Knohl, Alexander

2016-04-01

Global increase in demand of palm oil is leading to the expansion of oil palm plantations, particularly in SE Asia. Oil palm plantations in Sumatra, Indonesia, together with those in Kalimantan, are responsible for half of the world's palm oil production. Available studies point to plantations being large carbon dioxide (CO2) sinks due to the high photosynthetic rates of oil palm as a result of high fertilizer inputs, especially in large-scale plantations. However, methane (CH4) uptake in the soil of oil palm plantations is reduced and soil nitrous oxide (N2O) emissions increased right after nitrogen (N) fertilization. Greenhouse gas (GHG) budgets at the ecosystem level are still missing, and the few available information was derived from mature plantations, pointing to a lack of knowledge on the changes of these GHG budgets with plantation age. With the aim of quantifying CO2, CH4 and N2O fluxes during the non-productive and productive phases of oil palm cultivation, an eddy covariance (EC) tower was installed in a 2-year old (non-productive) oil palm plantation and was subsequently moved to a 12-year old (productive) plantation. Both sites were on Acrisol soils and were located in Jambi province, Sumatra. Chamber-based measurements of soil GHG fluxes were also carried out along the EC footprint. Net ecosystem exchange (NEE), based on EC measurement, showed that the non-productive plantation was a strong CO2 source (990 g C m-2 yr-1) whereas the productive plantation was a CO2 sink (-790 g C m-2 yr-1). For CH4 fluxes, both plantations showed similar soil CH4 uptake that led to a small carbon sink of (~1.3 g C m-2 yr-1). Soil N2O fluxes were high in the productive plantation (3.26 ± 1.73 kg N ha-1 yr-1), as measurements were carried out in a plantation with high fertilization rates. In the non-productive plantation, soil N2O fluxes were lower and were associated with fertilization events. Our results show that the global warming potential of a non-productive oil palm plantation was dominated by CO2 fluxes, whereas in a productive plantation N2O contribution to the global warming could be significant due to high N fertilizer input. Our results also highlight the need of evaluating various stages of development of oil palm cultivation when assessing their GHG budgets at a regional scale in order to support quantitative-based mitigation strategies.

The cultivation of energy crops for biogas production and the application of digestates are characterized by high variability of CO2 exchange and soil organic C stock changes

NASA Astrophysics Data System (ADS)

Augustin, Juergen; Fiedler, Sebastian; Heintze, Gawan; Rohwer, Marcus; Prescher, Anne-Katrin; Pohl, Madlen; Jurisch, Nicole; Hagemann, Ulrike

2017-04-01

In Germany, agricultural production accounts for approx. 15% of total anthropogenic greenhouse gas emissions. The cultivation of energy crops is thus considered an important option to reduce the climate impact and maintain or increase soil organic carbon (SOC) stocks. In particular, this applies to the continuously expanding cultivation of energy crops for biogas production and the associated use of residues from anaerobic digestion (digestates) as organic fertilizer. To date, there is only limited and contradicting evidence on the impacts of this management practice on the CO2 exchange as well as the change of SOC stocks. We will present results from a 4-year field study at 5 sites in Germany using identical methods to investigate the interacting effects of i) 3 N-fertilizer treatments including calcium ammonium nitrate and digestates and ii) a crop rotation of 7 energy crops like maize, sorghum, triticale, and wheat on net ecosystem CO2 exchange (NEE) and the change of SOC stocks. We used the manual chamber approach for measuring NEE as the difference between gross primary production and ecosystem respiration. The determination of SOC stock changes was based on a C budget approach, which includes the cumulated annual NEE, the C export by harvest, and the C import by application of anaerobic digestates. The CO2 exchange and the change of SOC stocks were influenced by multiple factors like crop, site, fertilization, and climate, as well as their complex interactions. A large proportion of the variability of the CO2 exchange can be attributed to interannual climatic variability. Productive crops like maize and sorghum generally feature the most intensive CO2 exchange, while less productive crops can compensate for this by means of longer cultivation times. Regardless of the extreme variability, pronounced and partly significant differences of NEE and C budgets between sites were observed. On average, SOC stocks declined over a full crop rotation, but with highly variable positive and negative C budgets. This indicates that, in most cases, neither the selected crops nor the application of anaerobic digestates were sufficient to compensate for SOC losses. Apparently, the potential of anaerobic digestates to maintain or increase SOC stocks is considerably smaller than expected. If continuous decreases of SOC stocks due to energy crop cultivation are to be avoided, additional studies on the optimization of crop rotations (selection of plants with high C input), and digestate fertilization (type of digestate, amount and application technique) are required. A continuously improved version of the methodology used in this study promises faster and more precise results than classic long-term field trials.

Crop yield changes induced by emissions of individual climate-altering pollutants

NASA Astrophysics Data System (ADS)

Shindell, Drew T.

2016-08-01

Climate change damages agriculture, causing deteriorating food security and increased malnutrition. Many studies have examined the role of distinct physical processes, but impacts have not been previously attributed to individual pollutants. Using a simple model incorporating process-level results from detailed models, here I show that although carbon dioxide (CO2) is the largest driver of climate change, other drivers appear to dominate agricultural yield changes. I calculate that anthropogenic emissions to date have decreased global agricultural yields by 9.5 ± 3.0%, with roughly 93% stemming from non-CO2 emissions, including methane (-5.2 ± 1.7%) and halocarbons (-1.4 ± 0.4%). The differing impacts stem from atmospheric composition responses: CO2 fertilizes crops, offsetting much of the loss induced by warming; halocarbons do not fertilize; methane leads to minimal fertilization but increases surface ozone which augments warming-induced losses. By the end of the century, strong CO2 mitigation improves agricultural yields by ˜3 ± 5%. In contrast, strong methane and hydrofluorocarbon mitigation improve yields by ˜16 ± 5% and ˜5 ± 4%, respectively. These are the first quantitative analyses to include climate, CO2 and ozone simultaneously, and hence, additional studies would be valuable. Nonetheless, as policy makers have leverage over pollutant emissions rather than isolated processes, the perspective presented here may be more useful for decision making than that in the prior work upon which this study builds. The results suggest that policies should target a broad portfolio of pollutant emissions in order to optimize mitigation of societal damages.

Fertility: purinergic receptors and the male contraceptive pill.

PubMed

Dunn, P M

2000-04-20

Knockout mice lacking the P2X(1) receptor appear normal, but fail to breed. Analysis of these mutant mice clearly shows that purinergic co-transmission has a physiological role in the was deferens. These findings also raise the possibility of developing non-hormonal ways of regulating male fertility.

The issues of energy and carbon cycle: new perspectives for assessing the environmental impact of animal waste utilization.

PubMed

Ceotto, E

2005-01-01

This paper focuses on the benefits of an efficient use of animal waste from the standpoint of curbing the rise of anthropogenic carbon dioxide (CO(2)) in the atmosphere. An effective use of animal waste resources might provide a partial, but still important, contribution in reducing net CO(2) emissions. In particular: the fulfillment of nutrient requirements of crop plants growing in non-limiting conditions and thus sequestering CO(2) at their potential level; the chance of diminishing the use of fossil energy, and related CO(2) emissions, required for manufacturing industrial fertilizers; the possibility of enhancing carbon sequestration in agricultural soils by the application of farmyard manure. The future success of agriculture in providing these ecosystem services can only be achieved with a changed social awareness of the links between sustainable land use and global environmental change.

Impacts of Stratospheric Sulfate Geoengineering on Chinese Agricultural Production

NASA Astrophysics Data System (ADS)

Xia, L.; Robock, A.

2012-12-01

Possible food supply change is one of the most important concerns in the discussion of stratospheric sulfate geoengineering. In China, the high population density and strong summer monsoon influence on agriculture make this region sensitive to climate changes, such as reductions of precipitation, temperature, and solar radiation spurred by stratospheric sulfate injection. We used results from the Geoengineering Model Intercomparison Project G2 scenario to force the Decision Support System for Agrotechnology Transfer (DSSAT) crop model to predict crop yield changes from rice, maize, and winter wheat. We first evaluated the DSSAT model by forcing it with daily observed weather data and management practices for the period 1978-2008 for all the provinces in China, and compared the results to observations of the yields of the three major crops in China. We then created two 50-year sets of climate anomalies using the results from eight climate models, for 1%/year increase of CO2 and for G2 (1%/year increase of CO2 balanced by insolation reduction), and compared the resulting agricultural responses. Considering that geoengineering could happen in the future, we used two geoengineering starting years, 2020 and 2060. For 2020, we increased the mean temperature by 1°C and started the CO2 concentration at 410 ppm. For 2060, we increased temperature by 2°C and started the CO2 concentration at 550 ppm. Without changing agriculture technology, we find that compared to the control run, geoengineering with the G2 scenario starting in 2020 or 2060 would both moderately increase rice and winter wheat production due to the CO2 fertilization effect, but the increasing rates are different. However, as a C4 crop, without a significant CO2 fertilization effect, maize production would decrease slightly because of regional drought. Compared to the reference run, the three crops all have less heat stress in southern China and their yields increase, but in northern China cooler temperatures cause yields to decrease, especially for winter wheat. Therefore after deploying geoengineering (G2), there are positive effects from temperature reduction, but regions with precipitation reduction may be harmful for agriculture activity. In addition, the starting year of geoengineering would affect its impacts on agriculture.

Coupling of N2O and CO2 fluxes from agriculture in Michigan

NASA Astrophysics Data System (ADS)

Cui, M.; Tang, J.; Hastings, M. G.; Gelfand, I.; Tao, L.; Sun, K.

2012-12-01

CO2 has been known to cause global warming, and N2O is the largest contributor to the greenhouse gas burden of cropping systems in the United States due to application of fertilizer. In our study, fluxes of N2O and CO2 were measured at two maize fields and one reference grassland from Kellogg Biological Station in Southwest Michigan. Here we compared two measuring systems, traditional GC method and LGR/Li-Cor system. Our initial results show that the two measuring systems are consistent (N2O slope=0.96, R2=0.96; and CO2 slope= 1.03, R2=0.86 measuring from the same chamber). Measurements done in pairs of chambers suggest great spatial variations, despite that the chambers were only 0.5 meter apart. The two systems are still comparable by averaging 8 pairs of chambers distributed within one site. Increase of CO2 fluxes were observed the second day after fertilization, but no significant change of N2O fluxes was shown. After artificial rainfall, boosting N2O fluxes and further increase in CO2 fluxes were demonstrated. Our result indicates that precipitation is necessary before a prominent N2O peak. In our LGR/Li-Cor system, CO was also measured from chambers. Interesting CO fluxes were shown in our experiment. Soil, which is usually considered as a CO sink, emits CO in some chambers during our measurement, which is probably related to the nationwide forest fires and lack of precipitation during the period.

Modification of land-atmosphere interactions by CO2 effects: Implications for summer dryness and heat wave amplitude

NASA Astrophysics Data System (ADS)

Lemordant, Léo.; Gentine, Pierre; Stéfanon, Marc; Drobinski, Philippe; Fatichi, Simone

2016-10-01

Plant stomata couple the energy, water, and carbon cycles. We use the framework of Regional Climate Modeling to simulate the 2003 European heat wave and assess how higher levels of surface CO2 may affect such an extreme event through land-atmosphere interactions. Increased CO2 modifies the seasonality of the water cycle through stomatal regulation and increased leaf area. As a result, the water saved during the growing season through higher water use efficiency mitigates summer dryness and the heat wave impact. Land-atmosphere interactions and CO2 fertilization together synergistically contribute to increased summer transpiration. This, in turn, alters the surface energy budget and decreases sensible heat flux, mitigating air temperature rise. Accurate representation of the response to higher CO2 levels and of the coupling between the carbon and water cycles is therefore critical to forecasting seasonal climate, water cycle dynamics, and to enhance the accuracy of extreme event prediction under future climate.

Differential response of kabuli and desi chickpea genotypes toward inoculation with PGPR in different soils

PubMed Central

Imran, Asma; Mirza, Muhammad S.; Shah, Tariq M.; Malik, Kauser A.; Hafeez, Fauzia Y.

2015-01-01

Pakistan is among top three chickpea producing countries but the crop is usually grown on marginal lands without irrigation and fertilizer application which significantly hampers its yield. Soil fertility and inoculation with beneficial rhizobacteria play a key role in nodulation and yield of legumes. Four kabuli and six desi chickpea genotypes were, therefore, evaluated for inoculation response with IAA-producing Ochrobactrum ciceri Ca-34T and nitrogen fixing Mesorhizobium ciceri TAL-1148 in single and co-inoculation in two soils. The soil type 1 was previously unplanted marginal soil having low organic matter, P and N contents compared to soil type 2 which was a fertile routinely legume-cultivated soil. The effect of soil fertility status was pronounced and fertile soil on average, produced 31% more nodules, 62% more biomass and 111% grain yield than marginal soil. Inoculation either with O. ciceri alone or its co-inoculation with M. ciceri produced on average higher nodules (42%), biomass (31%), grains yield (64%) and harvest index (72%) in both chickpea genotypes over non-inoculated controls in both soils. Soil 1 showed maximum relative effectiveness of Ca-34T inoculation for kabuli genotypes while soil 2 showed for desi genotypes except B8/02. Desi genotype B8/02 in soil type 1 and Pb-2008 in soil type 2 showed significant yield increase as compared to respective un-inoculated controls. Across bacterial inoculation treatments, grain yield was positively correlated to growth and yield contributing parameters (r = 0.294* to 0.838*** for desi and r = 0.388* to 0.857** for kabuli). PCA and CAT-PCA analyses clearly showed a site-specific response of genotype x bacterial inoculation. Furthermore, the inoculated bacterial strains were able to persist in the rhizosphere showing colonization on root and within nodules. Present study shows that plant growth promoting rhizobacteria (PGPR) inoculation should be integrated with national chickpea breading program in Pakistan especially for marginal soils. Furthermore, the study shows the potential of phytohormone producing strain Ca-34T as promising candidate for development of biofertilizer alongwith nodulating strains to get sustainable yield of kabuli and desi chickpea with minimum inputs at marginal land. PMID:26379638

Influence of soil organic C content on the greenhouse gas emission potential after application of biogas residues or cattle slurry - Results from a pot experiment

NASA Astrophysics Data System (ADS)

Heintze, Gawan

2017-04-01

Influence of soil organic C content on the greenhouse gas emission potential after application of biogas residues or cattle slurry - Results from a pot experiment Gawan Heintze1,2, Tim Eickenscheidt1, Urs Schmidthalter2 and Matthias Drösler1 1University of Applied Sciences Weihenstephan-Triesdorf, Chair of Vegetation Ecology, Weihenstephaner Berg 4, 85354 Freising, Germany 2Technische Universität München, Chair of Plant Nutrition, Emil-Ramann-Str. 2, 85354 Freising, Germany The European Union Renewable Energy Directive, which sets a binding target of a final energy consumption of 20% from renewable sources by 2020, has markedly promoted the increase of biogas plants, particularly in Germany. As a consequence, a large amount of biogas residue remains as a by-product of the fermentative process. These residues are now widely used instead of mineral fertilizers or animal slurries to maintain soil fertility and productivity. However, to date, the effect of the application of biogas residue on greenhouse gas (GHG) emission, compared to that of other organic fertilizers, is contradictory in literature, not having been completely understood. It is often stated that GHG fluxes are closely related to the quality of the raw material, particularly the type of soil to which the digestates are applied. This study addresses the questions (a) to what extent are the applications of biogas digestate and cattle slurry different in terms of their GHG emission (CO2, CH4 and N2O) potential, and (b) how do different soil organic carbon contents (SOCs) influence the rate of GHG exchange. We hypothesize that, i) cattle slurry application enhances the CO2 and N2O fluxes compared to the biogas digestate due to the overall higher C and N input, and ii) that with increasing SOC and N content, higher emissions of CO2 and N2O can be expected. The study was conducted as a pot experiment. Biogas digestate and cattle slurry were applied to and incorporated into three different soil types with varying SOC contents (Cambisol, termed Clow; Mollic Gleysol, termed Cmedium and Sapric Histosol, termed Chigh). The application rate was equivalent to 150 kg NH4+-N ha-1. GHG exchange (CO2, CH4 and N2O) was measured on five replicates over a period of 22 days using the closed chamber technique to simulate the high-risk situation of enhanced GHG emissions following organic fertilizer application in energy maize cultivation. Generally, it was found that the application of cattle slurry resulted in significantly higher CO2 and N2O fluxes compared to the application of biogas digestate. The total cumulative CO2 exchange rates after 22 days ranged from 137 ± 4.6 kg C ha-1 22d-1 (Clow, control) to 885 ± 32.5 kg C ha-1 22 d-1 (Chigh, CS). However, the total cumulative N2O exchange rates ranged from 7.7 ± 6.1 g N ha-1 22 d-1 (Clow, control) up to 2000 ± 226 g N ha-1 22 d-1 (Cmedium, CS). No differences were found regarding the CH4 exchange, which was close to zero for all treatments. Total cumulative CH4 exchange rates ranged between -31 ± 32 g C ha-1 22d-1 (Cmedium, control) and -167 ± 34 g C ha-1 22d-1 (Chigh, CS). Calculated cumulative emissions revealed that 4% to 15% of the C derived from the organic fertilizer was emitted as CO2, and 0.06% to 0.67% of the applied N as N2O. Significantly higher CO2 emissions were observed at the Chigh treatments compared to the other two soil types investigated, whereas the significantly highest N2O emissions were found at the Cmedium treatments. The results clearly demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions. Considering the distinctly higher global warming potential (GWP) of N2O compared to CO2 (298:1; IPCC 2014), the present results revealed that soil type-specific 22-day cumulative N2O emissions contributed to 8% of the total GWP balance at Clow, 25% at Cmedium and 4% at Chigh, respectively. Overall, it seems that soils rich in SOM have a higher sensitivity regarding changing physical soil conditions than soils with low SOM contents.

CO2 fertilization and enhanced drought resistance in Greek firs from Cephalonia Island, Greece.

PubMed

Koutavas, Athanasios

2013-02-01

Growth-climate relationships were investigated in Greek firs from Ainos Mountain on the island of Cephalonia in western Greece, using dendrochronology. The goal was to test whether tree growth is sensitive to moisture stress, whether such sensitivity has been stable through time, and whether changes in growth-moisture relationships support an influence of atmospheric CO2 on growth. Regressions of tree-ring indices (ad 1820-2007) with instrumental temperature, precipitation, and Palmer Drought Severity Index (PDSI) indicate that growth is fundamentally limited by growing-season moisture in late spring/early summer, most critically during June. However, this simple picture obscures a pattern of sharply evolving growth-climate relationships during the 20th century. Correlations between growth and June temperature, precipitation, and PDSI were significantly greater in the early 20th century but later degraded and disappeared. By the late 20th-early 21st century, there remains no statistically significant relationship between moisture and growth implying markedly enhanced resistance to drought. Moreover, growth experienced a net increase over the last half-century culminating with a sharp spike in ad 1988-1990. This recent growth acceleration is evident in the raw ring-width data prior to standardization, ruling out artifacts from statistical detrending. The vanishing relationship with moisture and parallel enhancement of growth are all the more notable because they occurred against a climatic backdrop of increasing aridity. The results are most consistent with a significant CO2 fertilization effect operating through restricted stomatal conductance and improved water-use efficiency. If this interpretation is correct, atmospheric CO2 is now overcompensating for growth declines anticipated from drier climate, suggesting its effect is unusually strong and likely to be detectable in other up-to-date tree-ring chronologies from the Mediterranean. © 2012 Blackwell Publishing Ltd.

In situ 13CO2 pulse labelling of field-grown eucalypt trees revealed the effects of potassium nutrition and throughfall exclusion on phloem transport of photosynthetic carbon.

PubMed

Epron, Daniel; Cabral, Osvaldo Machado Rodrigues; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo Zacharias; Trivelin, Paulo Cesar Ocheuze; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

2016-01-01

Potassium (K) is an important limiting factor of tree growth, but little is known of the effects of K supply on the long-distance transport of photosynthetic carbon (C) in the phloem and of the interaction between K fertilization and drought. We pulse-labelled 2-year-old Eucalyptus grandis L. trees grown in a field trial combining K fertilization (+K and -K) and throughfall exclusion (+W and -W), and we estimated the velocity of C transfer by comparing time lags between the uptake of (13)CO2 and its recovery in trunk CO2 efflux recorded at different heights. We also analysed the dynamics of the labelled photosynthates recovered in the foliage and in the phloem sap (inner bark extract). The mean residence time of labelled C in the foliage was short (21-31 h). The time series of (13)C in excess in the foliage was affected by the level of fertilization, whereas the effect of throughfall exclusion was not significant. The velocity of C transfer in the trunk (0.20-0.82 m h(-1)) was twice as high in +K trees than in -K trees, with no significant effect of throughfall exclusion except for one +K -W tree labelled in the middle of the drought season that was exposed to a more pronounced water stress (midday leaf water potential of -2.2 MPa). Our results suggest that besides reductions in photosynthetic C supply and in C demand by sink organs, the lower velocity under K deficiency is due to a lower cross-sectional area of the sieve tubes, whereas an increase in phloem sap viscosity is more likely limiting phloem transport under drought. In all treatments, 10 times less (13)C was recovered in inner bark extracts at the bottom of the trunk when compared with the base of the crown, suggesting that a large part of the labelled assimilates has been exported out of the phloem and replaced by unlabelled C. This supports the 'leakage-retrieval mechanism' that may play a role in maintaining the pressure gradient between source and sink organs required to sustain high velocity of phloem transport in tall trees. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of fertilization on growth and foliar nutrients of red alder seedlings.

Treesearch

M.A. Radwan

1987-01-01

Effects of P, K, Ca, Mg, S, Co, and Mo fertilizers on growth and foliar nutrients of red alder seedlings potted in Grove, Bunker, and Wishkah forest soils were determined. Growth in Grove soil was stimulated most by P, Ca, and P + Ca + Mg + K + S. Growth in Bunker soil was improved only by P. In Wishkah soil, best growth was obtained when P was used alone; all...

HIV/AIDS and Infertility: Emerging Problems in the Era of Highly Active Antiretrovirals

PubMed Central

Kushnir, Vitaly A.; Lewis, William

2011-01-01

Objective To review the effects of HIV/AIDS, associated co-morbid conditions, and side effects of antiretroviral treatment on fertility. Design A Pubmed computer search was performed to identify relevant articles. Setting Research institution. Intervention(s) None. Result(s) Biological alterations in reproductive physiology may account for sub-fertility in patients infected with HIV. Psychosocial factors in patients with HIV infection may affect reproductive desires and outcomes. Antiretroviral medications may have direct toxicity on gametes and embryos. Available evidence indicates that fertility treatments can be a safe option for HIV-discordant couples; although, potential risk of viral transmission cannot be completely eliminated. Conclusion(s) Reproductive desires are increasingly becoming prominent in the healthcare of young HIV-infected patients. Additional data is needed to address the effect of HIV and its treatments on fertility and reproductive outcomes. PMID:21722892

Viral effects on bacterial respiration, production and growth efficiency: Consistent trends in the Southern Ocean and the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Bonilla-Findji, Osana; Malits, Andrea; Lefèvre, Dominique; Rochelle-Newall, Emma; Lemée, Rodolphe; Weinbauer, Markus G.; Gattuso, Jean-Pierre

2008-03-01

To investigate the potential effects of viruses on bacterial respiration (BR), production (BP) and growth efficiency (BGE), experiments were performed using natural microbial communities from the coastal Mediterranean Sea, from a typical high-nutrient low-chlorophyll (HNLC) region in the Southern Ocean and from a naturally iron (Fe)-fertilized algal bloom above the Kerguelen Plateau (Southern Ocean). Seawater was sequentially filtered and concentrated to produce a bacterial concentrate, a viral concentrate and a virus-free ultrafiltrate. The combination of all three fractions served as treatments with active viruses. Heating or microwaving was used to inactivate viruses for the control treatments. Despite the differences in the initial trophic state and community composition of the study sites, consistent trends were found. In the presence of active viruses, BR was stimulated (up to 113%), whereas BP and BGE were reduced (up to 51%). Our results suggest that viruses enhance the role of bacteria as oxidizers of organic matter, hence as producers of CO 2, and remineralizers of CO 2, N, P and Fe. In the context of Fe-fertilization, this has important implications for the final fate of organic carbon in marine systems.

Interactions of CO2, temperature and management practices: simulations with a modified version of CERES-Wheat

NASA Technical Reports Server (NTRS)

Tubiello, F. N.; Rosenzweig, C.; Volk, T.

1995-01-01

A new growth subroutine was developed for CERES-Wheat, a computer model of wheat (Triticum aestivum) growth and development. The new subroutine simulates canopy photosynthetic response to CO2 concentrations and light levels, and includes the effects of temperature on canopy light-use efficiency. Its performance was compared to the original CERES-Wheat V-2 10 in 30 different cases. Biomass and yield predictions of the two models were well correlated (correlation coefficient r > 0.95). As an application, summer growth of spring wheat was simulated at one site. Modeled crop responses to higher mean temperatures, different amounts of minimum and maximum warming, and doubled CO2 concentrations were compared to observations. The importance of irrigation and nitrogen fertilization in modulating the wheat crop climatic responses were also analyzed. Specifically, in agreement with observations, rainfed crops were found to be more sensitive to CO2 increases than irrigated ones. On the other hand, low nitrogen applications depressed the ability of the wheat crop to respond positively to CO2 increases. In general, the positive effects of high CO2 on grain yield were found to be almost completely counterbalanced by the negative effects of high temperatures. Depending on how temperature minima and maxima were increased, yield changes averaged across management practices ranged from -4% to 8%.

Climate change impacts of US reactive nitrogen.

PubMed

Pinder, Robert W; Davidson, Eric A; Goodale, Christine L; Greaver, Tara L; Herrick, Jeffrey D; Liu, Lingli

2012-05-15

Fossil fuel combustion and fertilizer application in the United States have substantially altered the nitrogen cycle, with serious effects on climate change. The climate effects can be short-lived, by impacting the chemistry of the atmosphere, or long-lived, by altering ecosystem greenhouse gas fluxes. Here we develop a coherent framework for assessing the climate change impacts of US reactive nitrogen emissions, including oxides of nitrogen, ammonia, and nitrous oxide (N(2)O). We use the global temperature potential (GTP), calculated at 20 and 100 y, in units of CO(2) equivalents (CO(2)e), as a common metric. The largest cooling effects are due to combustion sources of oxides of nitrogen altering tropospheric ozone and methane concentrations and enhancing carbon sequestration in forests. The combined cooling effects are estimated at -290 to -510 Tg CO(2)e on a GTP(20) basis. However, these effects are largely short-lived. On a GTP(100) basis, combustion contributes just -16 to -95 Tg CO(2)e. Agriculture contributes to warming on both the 20-y and 100-y timescales, primarily through N(2)O emissions from soils. Under current conditions, these warming and cooling effects partially offset each other. However, recent trends show decreasing emissions from combustion sources. To prevent warming from US reactive nitrogen, reductions in agricultural N(2)O emissions are needed. Substantial progress toward this goal is possible using current technology. Without such actions, even greater CO(2) emission reductions will be required to avoid dangerous climate change.

Climate change impacts of US reactive nitrogen

PubMed Central

Pinder, Robert W.; Davidson, Eric A.; Goodale, Christine L.; Greaver, Tara L.; Herrick, Jeffrey D.; Liu, Lingli

2012-01-01

Fossil fuel combustion and fertilizer application in the United States have substantially altered the nitrogen cycle, with serious effects on climate change. The climate effects can be short-lived, by impacting the chemistry of the atmosphere, or long-lived, by altering ecosystem greenhouse gas fluxes. Here we develop a coherent framework for assessing the climate change impacts of US reactive nitrogen emissions, including oxides of nitrogen, ammonia, and nitrous oxide (N2O). We use the global temperature potential (GTP), calculated at 20 and 100 y, in units of CO2 equivalents (CO2e), as a common metric. The largest cooling effects are due to combustion sources of oxides of nitrogen altering tropospheric ozone and methane concentrations and enhancing carbon sequestration in forests. The combined cooling effects are estimated at −290 to −510 Tg CO2e on a GTP20 basis. However, these effects are largely short-lived. On a GTP100 basis, combustion contributes just −16 to −95 Tg CO2e. Agriculture contributes to warming on both the 20-y and 100-y timescales, primarily through N2O emissions from soils. Under current conditions, these warming and cooling effects partially offset each other. However, recent trends show decreasing emissions from combustion sources. To prevent warming from US reactive nitrogen, reductions in agricultural N2O emissions are needed. Substantial progress toward this goal is possible using current technology. Without such actions, even greater CO2 emission reductions will be required to avoid dangerous climate change. PMID:22547815

An Analysis of the Climate Change Mitigation Potential through Soil Organic Carbon Sequestration in a Corn Belt Watershed.

PubMed

Bhattarai, Mukesh Dev; Secchi, Silvia; Schoof, Justin

2017-01-01

Land-based carbon sequestration constitutes a major low cost and immediately viable option in climate change mitigation. Using downscaled data from eight atmosphere-ocean general circulation models for a simulation period between 2015 and 2099, we examine the carbon sequestration potential of alternative agricultural land uses in an intensively farmed Corn Belt watershed and the impact of climate change on crop yields. Our results show that switching from conventional tillage continuous corn to no-till corn-soybean can sequester the equivalent of 192.1 MtCO 2 eq of soil organic carbon per hectare with a sequestration rate of 2.26 MtCO 2 eq ha -1 yr -1 . Our results also indicate that switchgrass can sequester the equivalent of 310.7 MtCO 2 eq of soil organic carbon per hectare with a sequestration rate of 3.65 MtCO 2 eq ha -1 yr -1 . Our findings suggest that, unlike for corn and soybean yields, climate change does not have a significant effect on switchgrass yields, possibly due to the carbon fertilization effect.

An Analysis of the Climate Change Mitigation Potential through Soil Organic Carbon Sequestration in a Corn Belt Watershed

NASA Astrophysics Data System (ADS)

Bhattarai, Mukesh Dev; Secchi, Silvia; Schoof, Justin

2017-01-01

Land-based carbon sequestration constitutes a major low cost and immediately viable option in climate change mitigation. Using downscaled data from eight atmosphere-ocean general circulation models for a simulation period between 2015 and 2099, we examine the carbon sequestration potential of alternative agricultural land uses in an intensively farmed Corn Belt watershed and the impact of climate change on crop yields. Our results show that switching from conventional tillage continuous corn to no-till corn-soybean can sequester the equivalent of 192.1 MtCO2 eq of soil organic carbon per hectare with a sequestration rate of 2.26 MtCO2 eq ha-1 yr-1. Our results also indicate that switchgrass can sequester the equivalent of 310.7 MtCO2 eq of soil organic carbon per hectare with a sequestration rate of 3.65 MtCO2 eq ha-1 yr-1. Our findings suggest that, unlike for corn and soybean yields, climate change does not have a significant effect on switchgrass yields, possibly due to the carbon fertilization effect.

Management of irrigation frequency and nitrogen fertilization to mitigate GHG and NO emissions from drip-fertigated crops.

PubMed

Abalos, Diego; Sanchez-Martin, Laura; Garcia-Torres, Lourdes; van Groenigen, Jan Willem; Vallejo, Antonio

2014-08-15

Drip irrigation combined with split application of fertilizer nitrogen (N) dissolved in the irrigation water (i.e. drip fertigation) is commonly considered best management practice for water and nutrient efficiency. As a consequence, its use is becoming widespread. Some of the main factors (water-filled pore space, NH4(+) and NO3(-)) regulating the emissions of greenhouse gases (i.e. N2O, CO2 and CH4) and NO from agroecosystems can easily be manipulated by drip fertigation without yield penalties. In this study, we tested management options to reduce these emissions in a field experiment with a melon (Cucumis melo L.) crop. Treatments included drip irrigation frequency (weekly/daily) and type of N fertilizer (urea/calcium nitrate) applied by fertigation. Crop yield, environmental parameters, soil mineral N concentrations and fluxes of N2O, NO, CH4 and CO2 were measured during 85 days. Fertigation with urea instead of calcium nitrate increased N2O and NO emissions by a factor of 2.4 and 2.9, respectively (P<0.005). Daily irrigation reduced NO emissions by 42% (P<0.005) but increased CO2 emissions by 21% (P<0.05) compared with weekly irrigation. We found no relation between irrigation frequency and N2O emissions. Based on yield-scaled Global Warming Potential as well as NO cumulative emissions, we conclude that weekly fertigation with a NO3(-)-based fertilizer is the best option to combine agronomic productivity with environmental sustainability. Our study shows that adequate management of drip fertigation, while contributing to the attainment of water and food security, may provide an opportunity for climate change mitigation. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of natural and anthropogenic factors on the dynamics of CO2 emissions from chernozems soil

NASA Astrophysics Data System (ADS)

Syabruk, Olesia

2017-04-01

Twentieth century marked a significant expansion of agricultural production. Soil erosion caused by human activity, conversion of forests and grasslands to cropland, desertification, burning nutrient residues, drainage, excessive cultivation led to intense oxidation of soil carbon to the atmosphere and allocation of additional amounts of CO2. According to the UN Intergovernmental Panel on Climate Change, agriculture is one of the main sources of greenhouse gases emissions to the atmosphere. The thesis reveals main patterns of the impact of natural and anthropogenic factors on CO2 emissions in the chernozems typical and podzolized in a Left-bank Forest-Steppe of Ukraine, seasonal and annual dynamics. New provisions for conducting monitoring CO2 emissions from soil were developed by combining observations in natural and controlled conditions, which allows isolating the impact of hydrological, thermal and trophic factors. During the research, the methods for operational monitoring of emission of carbon losses were improved, using a portable infrared gas analyzer, which allows receiving information directly in the field. It was determined that the volumes of emission losses of carbon chernozems typical and podzolized Left-bank Forest-Steppe of Ukraine during the growing season are 480-910 kg/ha and can vary depending on the soil treatment ±( 4,0 - 6,0) % and fertilizer systems ± (3,8 - 7,1) %. The significant impact of long application of various fertilizer systems and soil treatment on the intensity of carbon dioxide emissions was investigated. It was found that most emission occurs in organic- mineral fertilizers systems with direct seeding. The seasonal dynamics of the potential capacity of the soil to produce CO2 were researched. Under identical conditions of humidity and temperature it has maximum in June and July and the gradual extinction of the autumn. It was determined that the intensity of the CO2 emission from the surface of chernozem fluctuates daily from 5 to 15 % of the average level. The influence of the crop on the allocation dynamics of CO2 was also investigates during the research. Due to root respiration, total CO2 flux from soil increases by an average of 12-32 % when growing grain crops. The mathematical models of dependency between the CO2 emissions intensity and hydrothermal conditions were developed. These models will allow to predict the volume of CO2 emissions from automorphic chernozems under different scenarios of weather conditions during warm period, based on generalizing models with the corrections depending on the method of cultivation, fertilization system and agricultural culture. As a result of the research, it was proved that there is a necessity to conduct periodic direct measurements of CO2 emission losses from the soil surface and to summarize the results in an annual cycle, which allows estimating the probable emission losses of carbon already in the first years of the introduction of new agricultural technologies.

Throughfall reduction and nutrient availability effects on carbon balance in loblolly pine plantations in the southeastern United States

NASA Astrophysics Data System (ADS)

Bracho, R. G.; Vogel, J.; Jokela, E. J.; Cucinella, J.; Noormets, A.; Laviner, M. A.; Gonzalez-Benecke, C. A.; Samuelson, L. J.; Markewitz, D.; Will, R.; Meek, C.; Seiler, J.; Strahm, B. D.; McElligott, K.; Martin, T.

2016-12-01

Planted loblolly pine covers over 11 million hectares in the southeastern United States. Occurring across a range of climatic conditions, these pine plantations are critical for the regional economy and offset a significant fraction of anthropogenic CO2 emissions. Loblolly pine productivity has been enhanced through genetic improvement and intensive silviculture. However, climate projections forecast higher air temperature and more variable precipitation patterns for the region. A critical question is how silvicultural practices will interact with projected climate change to affect loblolly pine carbon balance. A fertilization by throughfall reduction experiment was established in the spring of 2012 at four loblolly pine plantations at the margins of the natural range of the specie (Florida FL, Georgia GA, Oklahoma OK and Virginia VA). Net primary productivity (NPP) was estimated from repeated tree inventories and net ecosystem productivity (NEP) as the difference between NPP and heterotrophic respiration (RH). Soil respiration (RS) and RH were measured simultaneously several times during the experiment. Throughfall reduction significantly decreased surface soil water content at all sites. After four years of treatment, fertilization increased NPP at all sites and throughfall reduction had a negative effect on NPP at the GA and OK sites. The combination fertilization x throughfall reduction did not have a significant effect on NPP. RS and RH were, in general negatively affected by fertilization and throughfall reduction with differential responses between sites, leading to significant NEP increases under fertilization, while throughfall reduction increased NEP at FL and VA due to no effect on NPP and negative effect on RS. Fertilization offset the negative effect of throughfall reduction on NEP in the fertilization x throughfall reduction treatment. All sites were significant carbon sinks, accumulating from 3.5 to 24 Mg C ha-1 in a 3 year period under a range of climatic conditions, age and treatments.

Parthenogenesis in mated Chinese Painted quail (Coturnix chinensis) hens decreases sperm-egg penetration and alters albumen characteristics.

PubMed

Santa Rosa, P; Parker, H M; Kiess, A S; McDaniel, C D

2016-10-15

Parthenogenesis, embryonic development without fertilization, resembles very early embryonic mortality in fertilized eggs. Also, parthenogenesis alters egg albumen characteristics in virgin Chinese Painted quail hens genetically selected for parthenogenesis (PV). When these PV hens are mated (PM), hatchability is reduced versus control mated (CM) hens that were not genetically selected for parthenogenesis. However, it is unclear if parthenogenesis, which occurs in PM hens, reduces hatchability due to infertility and altered albumen characteristics. Sperm-egg penetration (SEP) holes are indicative of true fertilization and may be useful in identifying if eggs from PM hens exhibit a decrease in fertility versus CM hens. Therefore, the objectives of this study were to determine if parthenogenesis in PM hens (1) decreases SEP, (2) alters albumen characteristics similar to parthenogenesis in eggs from PV hens, and (3) yields albumen characteristics similar to fertilized eggs containing early mortality. Daily, PV and PM eggs were collected, labeled, and incubated for 10 days, then broken out to determine the incidence of parthenogenesis and albumen characteristics. Also daily, fresh PM and CM quail eggs were macroscopically examined to determine if an egg was infertile with no embryonic development, parthenogenetic, or fertile. Each of these eggs was then microscopically examined for SEP. For both PV and PM incubated eggs, parthenogenesis decreased albumen pH, O2, and protein concentrations yet increased Ca(2+) and CO2 concentrations versus eggs with no development. For incubated PM eggs, albumen pH and O2 were lower, yet CO2 was higher for eggs containing parthenogens or early dead embryos versus infertile eggs. For SEP, fresh eggs classified as infertile or parthenogenetic from PM and CM hens had similar SEP holes but only one sixth as many SEP holes as eggs classified as fertilized. Eggs from CM hens had 3.5 times as many SEP holes as PM eggs. In conclusion, parthenogenesis that occurs in mated quail hens inhibits fertility and alters albumen characteristics similarly to parthenogenesis in unfertilized eggs and early embryonic mortality in fertilized eggs. Copyright © 2016 Elsevier Inc. All rights reserved.

Nitrogen attenuation of terrestrial carbon cycle response to global environmental factors

USGS Publications Warehouse

Jain, A.A.; Yang, Xiaojuan; Kheshgi, H.; McGuire, A. David; Post, W.; Kicklighter, David W.

2009-01-01

Nitrogen cycle dynamics have the capacity to attenuate the magnitude of global terrestrial carbon sinks and sources driven by CO2 fertilization and changes in climate. In this study, two versions of the terrestrial carbon and nitrogen cycle components of the Integrated Science Assessment Model (ISAM) are used to evaluate how variation in nitrogen availability influences terrestrial carbon sinks and sources in response to changes over the 20th century in global environmental factors including atmospheric CO2 concentration, nitrogen inputs, temperature, precipitation and land use. The two versions of ISAM vary in their treatment of nitrogen availability: ISAM-NC has a terrestrial carbon cycle model coupled to a fully dynamic nitrogen cycle while ISAM-C has an identical carbon cycle model but nitrogen availability is always in sufficient supply. Overall, the two versions of the model estimate approximately the same amount of global mean carbon uptake over the 20th century. However, comparisons of results of ISAM-NC relative to ISAM-C reveal that nitrogen dynamics: (1) reduced the 1990s carbon sink associated with increasing atmospheric CO2 by 0.53 PgC yr−1 (1 Pg = 1015g), (2) reduced the 1990s carbon source associated with changes in temperature and precipitation of 0.34 PgC yr−1 in the 1990s, (3) an enhanced sink associated with nitrogen inputs by 0.26 PgC yr−1, and (4) enhanced the 1990s carbon source associated with changes in land use by 0.08 PgC yr−1 in the 1990s. These effects of nitrogen limitation influenced the spatial distribution of the estimated exchange of CO2 with greater sink activity in high latitudes associated with climate effects and a smaller sink of CO2 in the southeastern United States caused by N limitation associated with both CO2 fertilization and forest regrowth. These results indicate that the dynamics of nitrogen availability are important to consider in assessing the spatial distribution and temporal dynamics of terrestrial carbon sources and sinks.

Role of Marine Biology in Glacial-Interglacial CO2 Cycles

NASA Astrophysics Data System (ADS)

Kohfeld, Karen E.; Le Quéré, Corinne; Harrison, Sandy P.; Anderson, Robert F.

2005-04-01

It has been hypothesized that changes in the marine biological pump caused a major portion of the glacial reduction of atmospheric carbon dioxide by 80 to 100 parts per million through increased iron fertilization of marine plankton, increased ocean nutrient content or utilization, or shifts in dominant plankton types. We analyze sedimentary records of marine productivity at the peak and the middle of the last glacial cycle and show that neither changes in nutrient utilization in the Southern Ocean nor shifts in plankton dominance explain the CO2 drawdown. Iron fertilization and associated mechanisms can be responsible for no more than half the observed drawdown.

Changes in the microbial community during bioremediation of gasoline-contaminated soil.

PubMed

Leal, Aline Jaime; Rodrigues, Edmo Montes; Leal, Patrícia Lopes; Júlio, Aline Daniela Lopes; Fernandes, Rita de Cássia Rocha; Borges, Arnaldo Chaer; Tótola, Marcos Rogério

We aimed to verify the changes in the microbial community during bioremediation of gasoline-contaminated soil. Microbial inoculants were produced from successive additions of gasoline to municipal solid waste compost (MSWC) previously fertilized with nitrogen-phosphorous. To obtain Inoculant A, fertilized MSWC was amended with gasoline every 3 days during 18 days. Inoculant B received the same application, but at every 6 days. Inoculant C included MSWC fertilized with N-P, but no gasoline. The inoculants were applied to gasoline-contaminated soil at 10, 30, or 50g/kg. Mineralization of gasoline hydrocarbons in soil was evaluated by respirometric analysis. The viability of the inoculants was evaluated after 103 days of storage under refrigeration or room temperature. The relative proportions of microbial groups in the inoculants and soil were evaluated by FAME. The dose of 50g/kg of inoculants A and B led to the largest CO 2 emission from soil. CO 2 emissions in treatments with inoculant C were inversely proportional to the dose of inoculant. Heterotrophic bacterial counts were greater in soil treated with inoculants A and B. The application of inoculants decreased the proportion of actinobacteria and increased of Gram-negative bacteria. Decline in the density of heterotrophic bacteria in inoculants occurred after storage. This reduction was bigger in inoculants stored at room temperature. The application of stored inoculants in gasoline-contaminated soil resulted in a CO 2 emission twice bigger than that observed in uninoculated soil. We concluded that MSWC is an effective material for the production of microbial inoculants for the bioremediation of gasoline-contaminated soil. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Influence of fertilizer placement on gaseous loss (CO2, CH4, N2O, and NH4) under different tillage management practices in a corn cropping system

USDA-ARS?s Scientific Manuscript database

Tillage and fertilizer application methods could alter plant yield and quality of corn production. Thus, a field experiment was conducted at the Sand Mountain Research Station located in the Appalachian Plateau region of Northeast Alabama on a Hartsells fine sandy loam to evaluate tillage (conventi...

Elevated CO2 benefits the soil microenvironment in the rhizosphere of Robinia pseudoacacia L. seedlings in Cd- and Pb-contaminated soils.

PubMed

Huang, Shuping; Jia, Xia; Zhao, Yonghua; Bai, Bo; Chang, Yafei

2017-02-01

Soil contamination by heavy metals in combination with elevated atmospheric CO 2 has important effects on the rhizosphere microenvironment by influencing plant growth. Here, we investigated the response of the R. pseudoacacia rhizosphere microenvironment to elevated CO 2 in combination with cadmium (Cd)- and lead (Pb)-contamination. Organic compounds (total soluble sugars, soluble phenolic acids, free amino acids, and organic acids), microbial abundance and activity, and enzyme activity (urease, dehydrogenase, invertase, and β-glucosidase) in rhizosphere soils increased significantly (p < 0.05) under elevated CO 2 relative to ambient CO 2 ; however, l-asparaginase activity decreased. Addionally, elevated CO 2 alone affected soil microbial community in the rhizosphere. Heavy metals alone resulted in an increase in total soluble sugars, free amino acids, and organic acids, a decrease in phenolic acids, microbial populations and biomass, and enzyme activity, and a change in microbial community in rhizosphere soils. Elevated CO 2 led to an increase in organic compounds, microbial populations, biomass, and activity, and enzyme activity (except for l-asparaginase), and changes in microbial community under Cd, Pb, or Cd + Pb treatments relative to ambient CO 2 . In addition, elevated CO 2 significantly (p < 0.05) enhanced the removal ratio of Cd and Pb in rhizosphere soils. Overall, elevated CO 2 benefited the rhizosphere microenvironment of R. pseudoacacia seedlings under heavy metal stress, which suggests that increased atmospheric CO 2 concentrations could have positive effects on soil fertility and rhizosphere microenvironment under heavy metals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tidal marsh plant responses to elevated CO2 , nitrogen fertilization, and sea level rise.

PubMed

Adam Langley, J; Mozdzer, Thomas J; Shepard, Katherine A; Hagerty, Shannon B; Patrick Megonigal, J

2013-05-01

Elevated CO2 and nitrogen (N) addition directly affect plant productivity and the mechanisms that allow tidal marshes to maintain a constant elevation relative to sea level, but it remains unknown how these global change drivers modify marsh plant response to sea level rise. Here we manipulated factorial combinations of CO2 concentration (two levels), N availability (two levels) and relative sea level (six levels) using in situ mesocosms containing a tidal marsh community composed of a sedge, Schoenoplectus americanus, and a grass, Spartina patens. Our objective is to determine, if elevated CO2 and N alter the growth and persistence of these plants in coastal ecosystems facing rising sea levels. After two growing seasons, we found that N addition enhanced plant growth particularly at sea levels where plants were most stressed by flooding (114% stimulation in the + 10 cm treatment), and N effects were generally larger in combination with elevated CO2 (288% stimulation). N fertilization shifted the optimal productivity of S. patens to a higher sea level, but did not confer S. patens an enhanced ability to tolerate sea level rise. S. americanus responded strongly to N only in the higher sea level treatments that excluded S. patens. Interestingly, addition of N, which has been suggested to accelerate marsh loss, may afford some marsh plants, such as the widespread sedge, S. americanus, the enhanced ability to tolerate inundation. However, if chronic N pollution reduces the availability of propagules of S. americanus or other flood-tolerant species on the landscape scale, this shift in species dominance could render tidal marshes more susceptible to marsh collapse. © 2013 Blackwell Publishing Ltd.

Comment on “Mycorrhizal association as a primary control of the CO 2 fertilization effect”

DOE PAGES

Norby, R. J.; De Kauwe, M. G.; Walker, A. P.; ...

2017-01-26

Terrer et al. (Reports, 1 July 2016, p. 72) used meta-analysis of CO 2 enrichment experiments as evidence of an interaction between mycorrhizal symbiosis and soil nitrogen availability. The comment presented here challenges their database and biomass as the response metric, and hence their recommendation that incorporation of mycorrhizae in models will improve predictions of terrestrial ecosystem responses to increasing atmospheric CO 2.

Comment on “Mycorrhizal association as a primary control of the CO 2 fertilization effect”

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norby, R. J.; De Kauwe, M. G.; Walker, A. P.

Terrer et al. (Reports, 1 July 2016, p. 72) used meta-analysis of CO 2 enrichment experiments as evidence of an interaction between mycorrhizal symbiosis and soil nitrogen availability. The comment presented here challenges their database and biomass as the response metric, and hence their recommendation that incorporation of mycorrhizae in models will improve predictions of terrestrial ecosystem responses to increasing atmospheric CO 2.

Sequestration of Soil Carbon as Secondary Carbonates (Invited)

NASA Astrophysics Data System (ADS)

Lal, R.

2013-12-01

Rattan Lal Carbon Management and Sequestration Center The Ohio State University Columbus, OH 43210 USA Abstract World soils, the major carbon (C) reservoir among the terrestrial pools, contain soil organic C (SOC) and soil inorganic C (SIC). The SIC pool is predominant in soils of arid and semi-arid regions. These regions cover a land area of about 4.9x109 ha. The SIC pool in soils containing calcic and petrocalcic horizons is estimated at about 695-748 Pg (Pg = 1015 g = 1 gigaton) to 1-m depth. There are two types of carbonates. Lithogenic or primary carbonates are formed from weathering of carbonaceous rocks. Pedogenic or secondary carbonates are formed by dissolution of CO2 in the soil air to form carbonic acid and precipitation as carbonates of Ca+2 or Mg+2. It is the availability of Ca+2 or Mg+2 from outside the ecosystem that is essential to sequester atmospheric CO2. Common among outside sources of Ca+2 or Mg+2 are irrigation water, aerial deposition, sea breeze, fertilizers, manure and other amendments. The decomposition of SOC and root respiration may increase the partial pressure of CO2 in the soil air and lead to the formation of HCO_3^- upon dissolution in H20. Precipitation of secondary carbonates may result from decreased partial pressure of CO2 in the sub-soil, increased concentration of Ca+2, Mg+2 and HCO_3^- in soil solution, and decreased soil moisture content by evapotranspiration. Transport of bicarbonates in irrigated soils and subsequent precipitation above the ground water (calcrete), activity of termites and other soil fauna, and management of urban soils lead to formation of secondary carbonates. On a geologic time scale, weathering of silicate minerals and transport of the by-products into the ocean is a geological process of sequestration of atmospheric CO2. Factors affecting formation of secondary carbonates include land use, and soil and crop management including application of biosolids, irrigation and the quality of irrigation water, activity and species diversity of soil biota, management of soil fertility and application of Ca-bearing amendments (e.g., lime, single and triple super phosphate, manure), and adoption of conservation-effective measures which trap alluvial and aeolian sediments. Even the low rate of formation of secondary carbonates at 2-5 kg C/ha/yr has implications to aggregation, and microbiological and regolith properties. The isotropic composition of secondary carbonates is a useful tool for reconstructing paleoecological conditions. Researchable priorities include: 1) assessment of the depth distribution of CO2 concentration in soil air and its spatial and temporal variation in relation to tillage systems, crop residue management, fertilizer and manuring, irrigation, cover cropping, agroforestry, etc., 2) understanding the effects of micro and meso-climate (e.g., rainfall, evapotranspiration, air and soil temperatures) on CO2 concentration in soil air, 3) determination of the relation between soil profile characteristics (texture, structure, horizonation, hydrology) and secondary carbonates at present and under paleoecological conditions, 4) establishing the relationship between SOC and SIC pools, 5) determination of the impacts of deforestation, biomass burning, wild fires, drought, inundation, etc., on SIC dynamics, and 6) evaluating the effects of secondary carbonates on soil aggregation and water retention.

Greening of the Earth and its drivers

DOE PAGES

Zhu, Zaichun; Piao, Shilong; Myneni, Ranga B.; ...

2016-04-25

Global environmental change is rapidly altering the dynamics of terrestrial vegetation, with consequences for the functioning of the Earth system and provision of ecosystem services 1, 2. Yet how global vegetation is responding to the changing environment is not well established. Here we use three long-term satellite leaf area index (LAI) records and ten global ecosystem models to investigate four key drivers of LAI trends during 1982 2009. We show a persistent and widespread increase of growing season integrated LAI (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing LAImore » (browning). Factorial simulations with multiple global ecosystem models suggest that CO 2 fertilization effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (LCC) (4%). CO 2 fertilization effects explain most of the greening trends in the tropics, whereas climate change resulted in greening of the high latitudes and the Tibetan Plateau. LCC contributed most to the regional greening observed in southeast China and the eastern United States. In conclusion, the regional effects of unexplained factors suggest that the next generation of ecosystem models will need to explore the impacts of forest demography, differences in regional management intensities for cropland and pastures, and other emerging productivity constraints such as phosphorus availability.« less

Greening of the Earth and its drivers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Zaichun; Piao, Shilong; Myneni, Ranga B.

Global environmental change is rapidly altering the dynamics of terrestrial vegetation, with consequences for the functioning of the Earth system and provision of ecosystem services 1, 2. Yet how global vegetation is responding to the changing environment is not well established. Here we use three long-term satellite leaf area index (LAI) records and ten global ecosystem models to investigate four key drivers of LAI trends during 1982 2009. We show a persistent and widespread increase of growing season integrated LAI (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing LAImore » (browning). Factorial simulations with multiple global ecosystem models suggest that CO 2 fertilization effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (LCC) (4%). CO 2 fertilization effects explain most of the greening trends in the tropics, whereas climate change resulted in greening of the high latitudes and the Tibetan Plateau. LCC contributed most to the regional greening observed in southeast China and the eastern United States. In conclusion, the regional effects of unexplained factors suggest that the next generation of ecosystem models will need to explore the impacts of forest demography, differences in regional management intensities for cropland and pastures, and other emerging productivity constraints such as phosphorus availability.« less

Underground coal gasification with extended CO2 utilization as economic and carbon neutral approach to address energy and fertilizer supply shortages in Bangladesh

NASA Astrophysics Data System (ADS)

Nakaten, Natalie; Islam, Rafiqul; Kempka, Thomas

2014-05-01

The application of underground coal gasification (UCG) with proven carbon mitigation techniques may provide a carbon neutral approach to tackle electricity and fertilizer supply shortages in Bangladesh. UCG facilitates the utilization of deep-seated coal seams, not economically exploitable by conventional coal mining. The high-calorific synthesis gas produced by UCG can be used for e.g. electricity generation or as chemical raw material for hydrogen, methanol and fertilizer production. Kempka et al. (2010) carried out an integrated assessment of UCG operation, demonstrating that about 19 % of the CO2 produced during UCG may be mitigated by CO2 utilization in fertilizer production. In the present study, we investigated an extension of the UCG system by introducing excess CO2 storage in the gas deposit of the Bahkrabad gas field (40 km east of Dhaka, Bangladesh). This gas field still holds natural gas resources of 12.8 million tons of LNG equivalent, but is close to abandonment due to a low reservoir pressure. Consequently, applying enhanced gas recovery (EGR) by injection of excess carbon dioxide from the coupled UCG-urea process may mitigate carbon emissions and support natural gas production from the Bahkrabad gas field. To carry out an integrated techno-economic assessment of the coupled system, we adapted the techno-economic UCG-CCS model developed by Nakaten et al. (2014) to consider the urea and EGR processes. Reservoir simulations addressing EGR in the Bakhrabad gas field by utilization of excess carbon dioxide from the UCG process were carried out to account for the induced pressure increase in the reservoir, and thus additional gas recovery potentials. The Jamalganj coal field in Northwest Bangladesh provides favorable geological and infrastructural conditions for a UCG operation at coal seam depths of 640 m to 1,158 m. Excess CO2 can be transported via existing pipeline networks to the Bahkrabad gas field (about 300 km distance from the coal deposit) to be injected in the scope of the scheduled EGR operation. Our techno-economic modeling results considering EGR reservoir simulations demonstrate that an economic and carbon neutral operation of UCG combined with fertilizer production and CCS is feasible. The suggested approach may provide a bridging technology to tackle fertilizer and power supply shortages in Bangladesh, and in addition support further production from depleting natural gas deposits. References Kempka, T., Plötz, M.L., Hamann, J., Deowan, S.A., Azzam, R. (2010) Carbon dioxide utilisation for carbamide production by application of the coupled UCG-urea process. Energy Procedia 4: 2200-2205. Nakaten, N., Schlüter, R., Azzam, R., Kempka, T. (2014) Development of a techno-economic model for dynamic calculation of COE, energy demand and CO2 emissions of an integrated UCG-CCS process. Energy (in print). Doi 10.1016/j.energy.2014.01.014

Impact of ocean warming and ocean acidification on larval development and calcification in the sea urchin Tripneustes gratilla.

PubMed

Sheppard Brennand, Hannah; Soars, Natalie; Dworjanyn, Symon A; Davis, Andrew R; Byrne, Maria

2010-06-29

As the oceans simultaneously warm, acidify and increase in P(CO2), prospects for marine biota are of concern. Calcifying species may find it difficult to produce their skeleton because ocean acidification decreases calcium carbonate saturation and accompanying hypercapnia suppresses metabolism. However, this may be buffered by enhanced growth and metabolism due to warming. We examined the interactive effects of near-future ocean warming and increased acidification/P(CO2) on larval development in the tropical sea urchin Tripneustes gratilla. Larvae were reared in multifactorial experiments in flow-through conditions in all combinations of three temperature and three pH/P(CO2) treatments. Experiments were placed in the setting of projected near future conditions for SE Australia, a global change hot spot. Increased acidity/P(CO2) and decreased carbonate mineral saturation significantly reduced larval growth resulting in decreased skeletal length. Increased temperature (+3 degrees C) stimulated growth, producing significantly bigger larvae across all pH/P(CO2) treatments up to a thermal threshold (+6 degrees C). Increased acidity (-0.3-0.5 pH units) and hypercapnia significantly reduced larval calcification. A +3 degrees C warming diminished the negative effects of acidification and hypercapnia on larval growth. This study of the effects of ocean warming and CO(2) driven acidification on development and calcification of marine invertebrate larvae reared in experimental conditions from the outset of development (fertilization) shows the positive and negative effects of these stressors. In simultaneous exposure to stressors the dwarfing effects of acidification were dominant. Reduction in size of sea urchin larvae in a high P(CO2) ocean would likely impair their performance with negative consequent effects for benthic adult populations.

Impact of Ocean Warming and Ocean Acidification on Larval Development and Calcification in the Sea Urchin Tripneustes gratilla

PubMed Central

Sheppard Brennand, Hannah; Soars, Natalie; Dworjanyn, Symon A.; Davis, Andrew R.; Byrne, Maria

2010-01-01

Background As the oceans simultaneously warm, acidify and increase in P CO2, prospects for marine biota are of concern. Calcifying species may find it difficult to produce their skeleton because ocean acidification decreases calcium carbonate saturation and accompanying hypercapnia suppresses metabolism. However, this may be buffered by enhanced growth and metabolism due to warming. Methodology/Principal Findings We examined the interactive effects of near-future ocean warming and increased acidification/P CO2 on larval development in the tropical sea urchin Tripneustes gratilla. Larvae were reared in multifactorial experiments in flow-through conditions in all combinations of three temperature and three pH/P CO2 treatments. Experiments were placed in the setting of projected near future conditions for SE Australia, a global change hot spot. Increased acidity/P CO2 and decreased carbonate mineral saturation significantly reduced larval growth resulting in decreased skeletal length. Increased temperature (+3°C) stimulated growth, producing significantly bigger larvae across all pH/P CO2 treatments up to a thermal threshold (+6°C). Increased acidity (-0.3-0.5 pH units) and hypercapnia significantly reduced larval calcification. A +3°C warming diminished the negative effects of acidification and hypercapnia on larval growth. Conclusions and Significance This study of the effects of ocean warming and CO2 driven acidification on development and calcification of marine invertebrate larvae reared in experimental conditions from the outset of development (fertilization) shows the positive and negative effects of these stressors. In simultaneous exposure to stressors the dwarfing effects of acidification were dominant. Reduction in size of sea urchin larvae in a high P CO2 ocean would likely impair their performance with negative consequent effects for benthic adult populations. PMID:20613879

[Comparison of growth and field microclimate characteristics of broomcorn millet under different fertilization conditions].

PubMed

Zhang, Pan-pan; Zhou, Yu; Song, Hui; Qiao, Zhi-jun; Wang, Hai-gang; Zheng, Dian-feng; Feng, Bai-li

2015-02-01

A field experiment with two broomcorn millet varieties Longmi 8 (strong drought-resistant variety) and Jinmi 4 (drought-sensitive variety) was conducted to compare their differences in growth, field microclimate and photosynthetic capacity from anthesis to maturity under different fertility conditions. The results showed that, fertilization decreased canopy temperature, air temperature, soil temperature, illumination, but improved the relative humidity among broomcorn millet plants compared with the non-fertilization treatment. With an increase of the fertilizer level, the plant height, SPAD, LAI, net photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2 concentration in broomcorn millet showed an increasing trend, which of the high fertilization treatment were 9.2%, 15.1%, 56.6%, 17.8%, 24.6%, 14.2%, 29.7% higher than those of non-fertilization treatment, respectively. Compared with Jinmi 4, Longmi 8 showed a cold wet characteristic, with lower canopy temperature, air temperature, soil temperature; illumination, and higher plant height, LAI, SPAD and relative humidity during grain filling. Moreover, each photosynthetic index of Longmi 8 slowly decreased and extended the period of leaf photosynthetic function so as to accumulate more photosynthetic products.

Effects of the fungicides mancozeb and chlorothalonil on fluxes of CO2, N2O, and CH4 in a fertilized Colorado grassland soil

USGS Publications Warehouse

Kinney, C.A.; Mosier, A.R.; Ferrer, I.; Furlong, E.T.; Mandernack, K.W.

2004-01-01

Management of agricultural soil plays an important role in present and future atmospheric concentrations of the greenhouse gases carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). Pesticides are used as management tools in crop production, but little is known about their effects on soil-atmosphere exchange of CO2, N2O, and CH4. Field studies described in this paper determined the effect of two commonly used fungicides, mancozeb and chlorothalonil, on trace gas exchange. Separate experimental plots, 1 m2, were established in nitrogen fertilized no-tilled native grassland and tilled soils with and without fungicide application. Two studies were conducted. The first study was initiated in June 1999 and lasted for 1 year with monthly flux measurements from tilled and no-till soils. The second study commenced in August 2001 with twelve weekly measurements from tilled soils only. From both studies mancozeb suppressed emissions of CO2 and N2O in the tilled soil by an average of 28% and 47%, respectively. This suppression corresponded with efficacy periods of 14-29 and 56-77 days, respectively. From the no-till soils mancozeb decreased CO2 and N2O emissions by 33% and 80% for periods of 29 and 94 days, respectively. Mancozeb inhibited CH4 consumption in the first study by 46% and 71% in the tilled and no-till soil for periods of 8 and 29 days, respectively, but had no effect in the second study. From both studies chlorothalonil initially suppressed CO2 and N2O emissions and enhanced CH4 uptake in the tilled soil by an average of 37%, 40%, and 115%, respectively. These effects corresponded with efficacy periods of 14-29, 21-56, and 1-14 days, respectively. In the no-till soil chlorothalonil inhibited CO2 and N2O emissions and enhanced CH4 uptake by 29%, 48%, and 86% for periods of 29, 56, and 56 days, respectively. Following the initial period of suppression, chlorothalonil subsequently enhanced N2O emissions in the tilled soil by an average of 51% and in the no-till soil by 81% before returning to near background levels. The beginning of increased N2O emissions from the chlorothalonil-amended plots corresponded with a maximum soil concentration of the chlorothalonil degradate, 4-hydroxy-2, 5, 6-trichloroisophthalonitrile. The site specific global warming potential (GWP) resulting from the fluxes of CO2, N2O, and CH4 from all soils was determined to decrease by an average 26% and 21% as a result of a single application of mancozeb or chlorothalonil, respectively. The decrease in CO2 emissions in the fungicide-amended plots potentially could result in the conservation of as much as 1200 and 2400 kg C ha-1 yr-1 organic carbon in the tilled and no-till plots, respectively. Therefore it is feasible that application of certain fungicides to agricultural soil might lead to enhanced soil carbon sequestration and thus have additional positive effects on atmospheric CO2 concentrations. Copyright 2004 by the American Geophysical Union.

Nitrogen-mediated effects of elevated CO2 on intra-aggregate soil pore structure.

PubMed

Caplan, Joshua S; Giménez, Daniel; Subroy, Vandana; Heck, Richard J; Prior, Stephen A; Runion, G Brett; Torbert, H Allen

2017-04-01

Soil pore structure has a strong influence on water retention, and is itself influenced by plant and microbial dynamics such as root proliferation and microbial exudation. Although increased nitrogen (N) availability and elevated atmospheric CO 2 concentrations (eCO 2 ) often have interacting effects on root and microbial dynamics, it is unclear whether these biotic effects can translate into altered soil pore structure and water retention. This study was based on a long-term experiment (7 yr at the time of sampling) in which a C 4 pasture grass (Paspalum notatum) was grown on a sandy loam soil while provided factorial additions of N and CO 2 . Through an analysis of soil aggregate fractal properties supported by 3D microtomographic imagery, we found that N fertilization induced an increase in intra-aggregate porosity and a simultaneous shift toward greater accumulation of pore space in larger aggregates. These effects were enhanced by eCO 2 and yielded an increase in water retention at pressure potentials near the wilting point of plants. However, eCO 2 alone induced changes in the opposite direction, with larger aggregates containing less pore space than under control conditions, and water retention decreasing accordingly. Results on biotic factors further suggested that organic matter gains or losses induced the observed structural changes. Based on our results, we postulate that the pore structure of many mineral soils could undergo N-dependent changes as atmospheric CO 2 concentrations rise, having global-scale implications for water balance, carbon storage, and related rhizosphere functions. © 2016 John Wiley & Sons Ltd.

The influence of sperm concentration, length of the gamete co-culture and the evolution of different sperm parameters on the in vitro fertilization of prepubertal goat oocytes.

PubMed

Palomo, M J; Mogas, T; Izquierdo, D; Paramio, M T

2010-11-01

The aims of the present study were: (1) to evaluate the influence of sperm concentration (ranging from 0.5 × 10(6) to 4 × 10(6) spermatozoa/ml) and length of the gamete co-incubation time (2, 4, 6, 8, 10, 12, 16, 20, 24 or 28 h) on in vitro fertilization (IVF), assessing the sperm penetration rate; (2) to investigate the kinetics of different semen parameters as motility, viability and acrosome status during the co-culture period; and (3) to analyse the effect of the presence of cumulus-oocytes complexes (COCs) on these parameters. To achieve these objectives, several experiments were carried out using in vitro matured oocytes from prepubertal goats. The main findings of this work are that: (1) in our conditions, the optimum sperm concentration is 4 × 10(6) sperm/ml, as this sperm:oocyte ratio (approximately 28,000) allowed us to obtain the highest penetration rate, without increasing polyspermy incidence; (2) the highest percentage of viable acrosome-reacted spermatozoa is observed between 8-12 h of gamete co-culture, while the penetration rate is maximum at 12 h of co-incubation; and (3) the presence of COCs seems to favour the acrosome reaction of free spermatozoa on IVF medium, but not significantly. In conclusion, we suggest that a gamete co-incubation for 12-14 h, with a concentration of 4 × 10(6) sperm/ml, would be sufficient to obtain the highest rate of penetration, reducing the exposure of oocytes to high levels of reactive oxygen species produced by spermatozoa, especially when a high sperm concentration is used to increase the caprine IVF outcome.

The effects of household management practices on the global warming potential of urban lawns.

PubMed

Gu, Chuanhui; Crane, John; Hornberger, George; Carrico, Amanda

2015-03-15

Nitrous oxide (N2O) emissions are an important component of the greenhouse gas (GHG) budget for urban turfgrasses. A biogeochemical model DNDC successfully captured the magnitudes and patterns of N2O emissions observed at an urban turfgrass system at the Richland Creek Watershed in Nashville, TN. The model was then used to study the long-term (i.e. 75 years) impacts of lawn management practice (LMP) on soil organic carbon sequestration rate (dSOC), soil N2O emissions, and net Global Warming Potentials (net GWPs). The model simulated N2O emissions and net GWP from the three management intensity levels over 75 years ranged from 0.75 to 3.57 kg N ha(-1)yr(-1) and 697 to 2443 kg CO2-eq ha(-1)yr(-1), respectively, which suggested that turfgrasses act as a net carbon emitter. Reduction of fertilization is most effective to mitigate the global warming potentials of turfgrasses. Compared to the baseline scenario, halving fertilization rate and clipping recycle as an alternative to synthetic fertilizer can reduce net GWPs by 17% and 12%, respectively. In addition, reducing irrigation and mowing are also effective in lowering net GWPs. The minimum-maintenance LMP without irrigation and fertilization can reduce annual N2O emissions and net GWPs by approximately 53% and 70%, respectively, with the price of gradual depletion of soil organic carbon, when compared to the intensive-maintenance LMP. A lawn age-dependent best management practice is recommended: a high dose fertilizer input at the initial stage of lawn establishment to enhance SOC sequestration, followed by decreasing fertilization rate when the lawn ages to minimize N2O emissions. A minimum-maintained LMP with clipping recycling, and minimum irrigation and mowing, is recommended to mitigate global warming effects from urban turfgrass systems. Among all practices, clipping recycle may be a relatively malleable behavior and, therefore, a good target for interventions seeking to reduce the environmental impacts of lawn management through public education. Our results suggest that a long-term or a chronosequence study of turfgrasses with varying ages is warranted to capture the complete dynamics of contribution of turfgrasses to global warming. Copyright © 2015 Elsevier Ltd. All rights reserved.

Physiological Ecology of Mesozoic Polar Forests in a High CO2 Environment

PubMed Central

BEERLING, D. J.; OSBORNE, C. P.

2002-01-01

Fossils show that coniferous forests extended into polar regions during the Mesozoic, a time when models and independent palaeo‐CO2 indicators suggest that the atmospheric CO2 concentration was at least double that of the present day. Consequently, such polar forests would have experienced high CO2 interacting with an extreme variation in light. Here we describe an experiment investigating this plant–environment interaction for extant tree species that were important components of polar forests, and give results from the first year of treatment. Specifically, we tested the hypotheses that growth in elevated CO2 (1) stimulates photosynthesis; (2) reduces photoinhibition during the polar summer; and (3) reduces respiration of above‐ and below‐ground plant organs. Our results indicate that CO2 fertilization generally does not affect photosynthesis under continuous daylight characteristic of the polar summer but does increase it when the period of illumination is shorter. Growth in elevated CO2 did not alter the potential for photoinhibition. CO2 enrichment significantly reduced leaf and root respiration rates by 50 and 25 %, respectively, in a range of evergreen taxa. Incorporating these observed CO2 effects into numerical simulations using a process‐based model of coniferous forest growth indicates that a high palaeo‐CO2 concentration would have increased the productivity of Cretaceous conifer forests in northern Alaska. This results from decreased respiratory costs that more than compensate for the absence of high CO2–high temperature interactions during the polar summer. The longer‐term effects of CO2 enrichment on seasonal changes in the above‐ and below‐ground carbon balance of trees are discussed. PMID:12096745

Plant growth and fertility requires functional interactions between specific PABP and eIF4G gene family members

PubMed Central

2018-01-01

The initiation of protein synthesis requires the involvement of the eukaryotic translation initiation factor (eIF) 4G to promote assembly of the factors needed to recruit a 40S ribosomal subunit to an mRNA. Although many eukaryotes express two eIF4G isoforms that are highly similar, those in plants, referred to as eIF4G and eIFiso4G, are highly divergent in size, sequence, and domain organization. Species of the Brassicaceae and the Cleomaceae also express a divergent eIFiso4G isoform, referred to as eIFiso4G2, not found elsewhere in the plant kingdom. Despite their divergence, eIF4G and eIFiso4G interact with eIF4A, eIF4B, and eIF4E isoforms needed for binding an mRNA. eIF4G and eIFiso4G also interact with the poly(A)-binding protein (PABP) which promotes ribosome recruitment to an mRNA. Increasing the complexity of such an interaction, however, Arabidopsis also expresses three PABP isoforms (PAB2, PAB4, and PAB8) in vegetative and reproductive tissues. In this study, the functional interactions among the eIF4G and the widely-expressed PABP isoforms were examined. Loss of PAB2 or PAB8 in combination with loss of eIF4G or eIFiso4G had little to no effect on growth or fertility whereas pab2 pab8 eif4g or pab2 pab8 eifiso4g1/2 mutants exhibited smaller stature and reduced fertility. Although the pab4 eifiso4g1 mutant grows normally and is fertile, pab4 eif4g or pab4 eifiso4g2 mutants could not be isolated. Even pab4/PAB4 eif4g/eIF4G heterozygous plants exhibited growth defects and low fertility. Mutant co-inheritance analysis in reciprocal crosses with wild-type plants revealed that most ovaries and pollen from pab4/PAB4 eif4g/eIF4G plants were PAB4 eif4g. Similarly, co-inheritance studies with pab4/PAB4 eifiso4g2/eIFiso4G2 plants suggested most ovaries were PAB4 eifiso4g2. These results suggest that a functional interaction between PAB4 and eIF4G and between PAB4 and eIFiso4G2 is required for growth and normal fertility. PMID:29381712

The immediate impact of semen diluent and rate of dilution on the sperm quality index, ATP utilization, gas exchange, and ionic balance of broiler breeder sperm.

PubMed

Parker, H M; McDaniel, C D

2006-01-01

The sperm quality index (SQI) is a tool used to predict overall rooster semen quality, fertility, and hatchability. However, semen must be diluted before SQI analysis, and research has shown that the SQI is most predictive of fertility at lower semen dilutions. Therefore, the present study was undertaken to determine why the SQI is not as predictive of fertility at higher semen dilutions and whether semen diluent type alters the SQI, adenosine triphosphate (ATP) utilization, gas exchange, and ionic balance of broiler breeder sperm. Semen was diluted with saline, seminal plasma, or minimum essential medium (MEM) from 2- to 200-fold. The following parameters were measured for each diluent type at each dilution: SQI, ATP, Na+, Ca2+, K+, Cl-, CO2, and O2. To examine the rate of sperm motility, the SQI was expressed as SQI/million sperm per mL (SQI/sperm). There was an interaction between diluent type and dilution for the SQI, SQI/sperm, CO2 generated, O2 used, as well as Na+, Ca2+, and K+ internalization. For sperm diluted with saline, the SQI declined more rapidly with increasing dilution. However, SQI/sperm increased rapidly when semen was diluted with MEM or SP. Sperm diluted in SP used ATP with increasing dilution whereas sperm diluted with saline and MEM generated ATP. Neat semen contained no free O2; however, each diluent type contained abundant O2 resulting in more O2 available as semen was diluted. Sperm diluted in SP produced more CO2 and used more O2 than semen diluted in saline or MEM. For SQI/sperm, ATP and CO2 generated, as well as Na+ and Ca2+ internalization, differences between diluent types occurred when semen was diluted 50-fold and greater. In conclusion, it appears that sperm motility, ATP utilization, gas exchange, and ionic balance are altered by diluent type and rate of dilution. These alterations in semen quality are exacerbated at semen dilutions of 50-fold and greater yielding an SQI that is not indicative of sperm motility or fertility.

Temperature modulates the response of the thermophilous sea urchin Arbacia lixula early life stages to CO2-driven acidification.

PubMed

Gianguzza, Paola; Visconti, Giulia; Gianguzza, Fabrizio; Vizzini, Salvatrice; Sarà, Gianluca; Dupont, Sam

2014-02-01

The increasing abundances of the thermophilous black sea urchin Arbacia lixula in the Mediterranean Sea are attributed to the Western Mediterranean warming. However, few data are available on the potential impact of this warming on A. lixula in combination with other global stressors such as ocean acidification. The aim of this study is to investigate the interactive effects of increased temperature and of decreased pH on fertilization and early development of A. lixula. This was tested using a fully crossed design with four temperatures (20, 24, 26 and 27 °C) and two pH levels (pHNBS 8.2 and 7.9). Temperature and pH had no significant effect on fertilization and larval survival (2d) for temperature <27 °C. At 27 °C, the fertilization success was very low (<1%) and all larvae died within 2d. Both temperature and pH had effects on the developmental dynamics. Temperature appeared to modulate the impact of decreasing pH on the % of larvae reaching the pluteus stage leading to a positive effect (faster growth compared to pH 8.2) of low pH at 20 °C, a neutral effect at 24 °C and a negative effect (slower growth) at 26 °C. These results highlight the importance of considering a range of temperatures covering today and the future environmental variability in any experiment aiming at studying the impact of ocean acidification. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterizing differences in the phosphorus activation coefficient of three typical cropland soils and the influencing factors under long-term fertilization.

PubMed

Wu, Qihua; Zhang, Shuxiang; Zhu, Ping; Huang, Shaomin; Wang, Boren; Zhao, LinPing; Xu, Minggang

2017-01-01

The phosphorus activation coefficient (PAC, the ratio of available P to total P) is an important indicator of soil P availability and the transformation of P fractions. Understanding the details of the PAC is useful to estimate soil available P status and to provide P management guidance. In this research, soils from five long-term (23 years) fertilization treatments in three croplands were selected to examine the relationships between the PAC and P fractions and to analyse the influencing factors. PAC was affected by both soil types and fertilization treatments. Compared to the unfertilized control (CK) treatment, long-term P application significantly increased the PAC, all of the inorganic P (Pi) fractions and most of the organic P (Po) fractions in all the three soils, particularly in chemical fertilizer combined with manure treatment (NPKM). The PAC was significantly correlated to all of the Pi fractions proportions (P<0.05) except for Dil. HCl-Pi and Conc. HCl-Pi. Compared with CK, the chemical P and chemical P combined with manure treatments increased the ratio of total Pi fractions to total Po fractions (Pit/Pot); furthermore, NPKM significantly increased the organic C (Co) content and decreased the Co/Pot ratio. Stepwise multiple regressions showed that PAC = 0.93 Co+0.69 Pit/Pot-0.07 Co/Pot-0.27CaCO3-3.79 (R2 = 0.924, P<0.001). In addition, the variance partitioning analysis showed that more variance of PAC is explained by soil factors (29.53%) than by P input (0.19%) and climate (0.25%) factors. Our findings demonstrate that P application increased the PAC by changing the Co content and the proportion of P fractions. Moreover, soil factors were the most important drivers of P transformations, and NPKM was optimal for improving soil fertility in Chinese croplands.

Characterizing differences in the phosphorus activation coefficient of three typical cropland soils and the influencing factors under long-term fertilization

PubMed Central

Wu, Qihua; Zhang, Shuxiang; Zhu, Ping; Huang, Shaomin; Wang, Boren; Zhao, LinPing; Xu, Minggang

2017-01-01

The phosphorus activation coefficient (PAC, the ratio of available P to total P) is an important indicator of soil P availability and the transformation of P fractions. Understanding the details of the PAC is useful to estimate soil available P status and to provide P management guidance. In this research, soils from five long-term (23 years) fertilization treatments in three croplands were selected to examine the relationships between the PAC and P fractions and to analyse the influencing factors. PAC was affected by both soil types and fertilization treatments. Compared to the unfertilized control (CK) treatment, long-term P application significantly increased the PAC, all of the inorganic P (Pi) fractions and most of the organic P (Po) fractions in all the three soils, particularly in chemical fertilizer combined with manure treatment (NPKM). The PAC was significantly correlated to all of the Pi fractions proportions (P<0.05) except for Dil. HCl-Pi and Conc. HCl-Pi. Compared with CK, the chemical P and chemical P combined with manure treatments increased the ratio of total Pi fractions to total Po fractions (Pit/Pot); furthermore, NPKM significantly increased the organic C (Co) content and decreased the Co/Pot ratio. Stepwise multiple regressions showed that PAC = 0.93 Co+0.69 Pit/Pot-0.07 Co/Pot-0.27CaCO3-3.79 (R2 = 0.924, P<0.001). In addition, the variance partitioning analysis showed that more variance of PAC is explained by soil factors (29.53%) than by P input (0.19%) and climate (0.25%) factors. Our findings demonstrate that P application increased the PAC by changing the Co content and the proportion of P fractions. Moreover, soil factors were the most important drivers of P transformations, and NPKM was optimal for improving soil fertility in Chinese croplands. PMID:28467425

76 FR 65653 - New Source Performance Standards (NSPS) Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-24

..., PM 2.5 , PM 10 ), nitrogen oxides (NO X ), carbon monoxide (CO), lead (Pb), volatile organic... Refineries Ja 06/24/2008 (73FR35867) 12/22/2008 \\4\\ (73FR78552) (Stay) Phosphate Fertilizers--Diammonium V 08/06/1975 (40FR33155) 10/17/2000 3 4 (65FR61757) Phosphate Plants. Phosphate Fertilizers--Granular X 08...

Reconciling top-down and bottom-up estimates of CO2 fluxes to understand increased seasonal exchange in Northern ecosystems

NASA Astrophysics Data System (ADS)

Bastos, A.; Ciais, P.; Zhu, D.; Maignan, F.; Wang, X.; Chevallier, F.; Ballantyne, A.

2017-12-01

Continuous atmospheric CO2 monitoring data indicate enhanced seasonal exchange in the high-latitudes in the Northern Hemisphere (above 40oN), mainly attributed to terrestrial ecosystems. Whether this enhancement is mostly explained by increased vegetation growth due to CO2 fertilization and warming, or by changes in land-use and land-management practices is still an unsettled question (e.g. Forkel et al. (2016) and Zeng et al. (2013)). Previous studies have shown that models present variable performance in capturing trends in CO2 amplitude at CO2 monitoring sites, and that Earth System Models present large spread in their estimates of such trends. Here we integrate data of atmospheric CO2 exchange in terrestrial ecosystems by a set of atmospheric CO2 inversions and a range of land-surface models to evaluate the ability of models to reproduce changes in CO2 seasonal exchange within the observation uncertainty. We then analyze the factors that explain the model spread to understand if the trend in seasonal CO2 amplitude may indeed be a useful metric to constrain future changes in terrestrial photosynthesis (Wenzel et al., 2016). We then compare model simulations with satellite and other observation-based datasets of vegetation productivity, biomass stocks and land-cover change to test the contribution of natural (CO2 fertilization, climate) and human (land-use change) factors to the increasing trend in seasonal CO2 amplitude. Forkel, Matthias, et al. "Enhanced seasonal CO2 exchange caused by amplified plant productivity in northern ecosystems." Science 351.6274 (2016): 696-699. Wenzel, Sabrina, et al. "Projected land photosynthesis constrained by changes in the seasonal cycle of atmospheric CO2." Nature 538, no. 7626 (2016): 499-501.Zeng, Ning, et al. "Agricultural Green Revolution as a driver of increasing atmospheric CO2 seasonal amplitude." Nature 515.7527 (2014): 394.

Use of sugarcane filter cake and nitrogen, phosphorus and potassium fertilization in the process of bioremediation of soil contaminated with diesel.

PubMed

Tellechea, Fernando Reynel Fundora; Martins, Marco Antônio; da Silva, Alexsandro Araujo; da Gama-Rodrigues, Emanuela Forestieri; Martins, Meire Lelis Leal

2016-09-01

This study evaluated the use of sugarcane filter cake and nitrogen, phosphorus and potassium (NPK) fertilization in the bioremediation of a soil contaminated with diesel fuel using a completely randomized design. Five treatments (uncontaminated soil, T1; soil contaminated with diesel, T2; soil contaminated with diesel and treated with 15 % (wt) filter cake, T3; soil contaminated with diesel and treated with NPK fertilizer, T4; and soil contaminated with diesel and treated with 15 % (wt) filter cake and NPK fertilizer, T5) and four evaluation periods (1, 60, 120, and 180 days after the beginning of the experiment) were used according to a 4 × 5 factorial design to analyze CO2 release. The variables total organic carbon (TOC) and total petroleum hydrocarbons (TPH) remaining in the soil were analyzed using a 5 × 2 factorial design, with the same treatments described above and two evaluation periods (1 and 180 days after the beginning of the experiment). In T3 and T5, CO2 release was significantly higher, compared with the other treatments. Significant TPH removal was observed on day 180, when percent removal values were 61.9, 70.1, 68.2, and 75.9 in treatments T2, T3, T4, and T5, respectively, compared with the initial value (T1).

Greenhouse gas budget (CO2, CH4 and N2O) of intensively managed grassland following restoration.

PubMed

Merbold, Lutz; Eugster, Werner; Stieger, Jacqueline; Zahniser, Mark; Nelson, David; Buchmann, Nina

2014-06-01

The first full greenhouse gas (GHG) flux budget of an intensively managed grassland in Switzerland (Chamau) is presented. The three major trace gases, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were measured with the eddy covariance (EC) technique. For CO2 concentrations, an open-path infrared gas analyzer was used, while N2O and CH4 concentrations were measured with a recently developed continuous-wave quantum cascade laser absorption spectrometer (QCLAS). We investigated the magnitude of these trace gas emissions after grassland restoration, including ploughing, harrowing, sowing, and fertilization with inorganic and organic fertilizers in 2012. Large peaks of N2O fluxes (20-50 nmol m(-2) s(-1) compared with a <5 nmol m(-2) s(-1) background) were observed during thawing of the soil after the winter period and after mineral fertilizer application followed by re-sowing in the beginning of the summer season. Nitrous oxide (N2O) fluxes were controlled by nitrogen input, plant productivity, soil water content and temperature. Management activities led to increased variations of N2O fluxes up to 14 days after the management event as compared with background fluxes measured during periods without management (<5 nmol m(-2) s(-1)). Fluxes of CO2 remained small until full plant development in early summer 2012. In contrast, methane emissions showed only minor variations over time. The annual GHG flux budget was dominated by N2O (48% contribution) and CO2 emissions (44%). CH4 flux contribution to the annual budget was only minor (8%). We conclude that recently developed multi-species QCLAS in an EC system open new opportunities to determine the temporal variation of N2O and CH4 fluxes, which further allow to quantify annual emissions. With respect to grassland restoration, our study emphasizes the key role of N2O and CO2 losses after ploughing, changing a permanent grassland from a carbon sink to a significant carbon source. © 2014 John Wiley & Sons Ltd.

The effects of climatic and CO[sub 2] changes on grassland storage of soil carbon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ojima, D.S.; Parton, W.J.; Schimel, D.S.

1993-06-01

We present results from analysis of the sensitivity of global grassland ecosystems to modified climate. We assess over 30 grassland sites from around the world under two different GCM double CO[sub 2] climates. The results indicate that soil C losses occur in Ar grassland regions (losses range from 1.6 to 8.8% of current soil C levels for the surface 20 cm). The Eurasian grasslands lost the greatest amount of soil C ([approximately]700 g C/m[sub 2]) and the other temperate grasslands lost approximately half this amount. The tropical grasslands and savannas lost the least amount of soil C per unit areamore » (ranging from no change to 130 g C/m[sub 2] losses). Plant production varies according to modifications in rainfall amounts under the altered climate and to altered nitrogen mineralization rates. The two GCM's differed in predictions of rainfall with a doubling of CO[sub 2], and this difference is reflected in plant production. Soil decomposition rates responded most predictably to changes in temperature. CO[sub 2] fertilization effects on soil C loss and plant production tended to reduce the net impact of climate alterations.« less

Effects of elevated CO(2) concentration and nutrition on net photosynthesis, stomatal conductance and needle respiration of field-grown Norway spruce trees.

PubMed

Roberntz, Peter; Stockfors, Jan

1998-04-01

To study the effects of elevated CO(2) on gas exchange, nonstructural carbohydrate and nutrient concentrations in current-year foliage of 30-year-old Norway spruce (Picea abies (L.) Karst.) trees, branches were enclosed in ventilated, transparent plastic bags and flushed with ambient air (mean 370 &mgr;mol CO(2) mol(-1); control) or ambient air + 340 &mgr;mol CO(2) mol(-1) (elevated CO(2)) during two growing seasons. One branch bag was installed on each of 24 selected trees from control and fertilized plots. To reduce the effect of variation among trees, results from each treated branch were compared with those from a control branch on the same whorl of the same tree. Elevated CO(2) increased rates of light-saturated photosynthesis on average by 55% when measured at the treatment CO(2) concentration. The increase was larger in shoots with high needle nitrogen concentrations than in shoots with low needle nitrogen concentrations. However, shoots grown in elevated CO(2) showed a decrease in photosynthetic capacity compared with shoots grown in ambient CO(2). When measured at the internal CO(2) concentration of 200 &mgr;mol CO(2) mol(-1), photosynthetic rates of branches in the elevated CO(2) treatments were reduced by 8 to 32%. The elevated CO(2) treatment caused a 9 to 20% reduction in carboxylation efficiency and an 18% increase in respiration rates. In response to elevated CO(2), starch, fructose and glucose concentrations in the needles increased on average 33%, whereas concentrations of potassium, nitrogen, phosphorus, magnesium and boron decreased. Needle nitrogen concentrations explained 50-60% of the variation in photosynthesis and CO(2) acclimation was greater at low nitrogen concentrations than at high nitrogen concentrations. We conclude that the enhanced photosynthetic rates found in shoots exposed to elevated CO(2) increased carbohydrate concentrations, which may have a negative feedback on the photosynthetic apparatus and stimulate cyanide-resistant respiration. We also infer that the decrease in nutrient concentrations of needles exposed to elevated CO(2) was the result of retranslocation of nutrients to other parts of the branch or tree.

Ocean Acidification: Coccolithophore's Light Controlled Effect on Alkalinity

NASA Astrophysics Data System (ADS)

Dobbins, W.

2015-12-01

Coccolithophorids, which play a significant role in the flux of calcite and organic carbon from the photic region to deeper pelagic and benthic zones, are potentially far more useful than siliceous phytoplankton for ocean fertilization projects designed to sequester CO2. However, the production of H+ ions during calcification (HCO3 + Ca+ —> CaCO3 + H+) has resulted in localized acidification around coccolithophore blooms. It has been hypothesized that under the correct light conditions photosynthesis could proceed at a rate such that CO2 is removed in amounts equimolar or greater than the H+ produced by calcification, allowing stable or increasing alkalinity despite ongoing calcification. Previously, this effect had not been demonstrated under laboratory conditions. Fifteen Emiliania huxleyi cultures were separated into equal groups with each receiving: 0, 6, 12, 18, or 24 hours of light each day for 24 days. Daily pH, cell density, and temperature measurements revealed a strong positive correlation between light exposure and pH, and no significant decline in pH in any of the cultures. Alkalinity increases were temperature independent and not strongly correlated with cell density, implying photosynthetic removal of carbon dioxide as the root cause. The average pH across living cultures increased from 7.9 to 8.3 over the first week and changed little for the reminder of the 24-day period. The results demonstrate coccolithophorids can increase alkalinity across a broad range of cell densities, despite the acidification inherent to the calcification process. If the light-alkalinity effect reported here proves scalable to larger cultures, Emiliania huxleyi are a strong candidate for carbon sequestration via targeted ocean fertilization.

Estimating Trends and Variation of Net Biome Productivity in India for 1980-2012 Using a Land Surface Model

NASA Astrophysics Data System (ADS)

Gahlot, Shilpa; Shu, Shijie; Jain, Atul K.; Baidya Roy, Somnath

2017-11-01

In this paper we explore the trend in net biome productivity (NBP) over India for the period 1980-2012 and quantify the impact of different environmental factors, including atmospheric CO2 concentrations ([CO2]), land use and land cover change, climate, and nitrogen deposition on carbon fluxes using a land surface model, Integrated Science Assessment Model. Results show that terrestrial ecosystems of India have been a carbon sink for this period. Driven by a strong CO2 fertilization effect, magnitude of NBP increased from 27.17 TgC/yr in the 1980s to 34.39 TgC/yr in the 1990s but decreased to 23.70 TgC/yr in the 2000s due to change in climate. Adoption of forest conservation, management, and reforestation policies in the past decade has promoted carbon sequestration in the ecosystems, but this effect has been offset by loss of carbon from ecosystems due to rising temperatures and decrease in precipitation.

Water balance and N-metabolism in broccoli (Brassica oleracea L. var. Italica) plants depending on nitrogen source under salt stress and elevated CO2.

PubMed

Zaghdoud, Chokri; Carvajal, Micaela; Ferchichi, Ali; Del Carmen Martínez-Ballesta, María

2016-11-15

Elevated [CO2] and salinity in the soils are considered part of the effects of future environmental conditions in arid and semi-arid areas. While it is known that soil salinization decreases plant growth, an increased atmospheric [CO2] may ameliorate the negative effects of salt stress. However, there is a lack of information about the form in which inorganic nitrogen source may influence plant performance under both conditions. Single factor responses and the interactive effects of two [CO2] (380 and 800ppm), three different NO3(-)/NH4(+) ratios in the nutrient solution (100/0, 50/50 and 0/100, with a total N concentration of 3.5mM) and two NaCl concentrations (0 and 80mM) on growth, leaf gas exchange parameters in relation to root hydraulic conductance and N-assimilating enzymes of broccoli (Brassica oleracea L. var. Italica) plants were determined. The results showed that a reduced NO3(-) or co-provision of NO3(-) and NH4(+) could be an optimal source of inorganic N for broccoli plants. In addition, elevated [CO2] ameliorated the effect of salt exposure on the plant growth through an enhanced rate of photosynthesis, even at low N-concentration. However, NO3(-) or NO3(-)/NH4(+) co-provision display differential plant response to salt stress regarding water balance, which was associated to N metabolism. The results may contribute to our understanding of N-fertilization modes under increasing atmospheric [CO2] to cope with salt stress, where variations in N nutrition significantly influenced plant response. Copyright © 2016 Elsevier B.V. All rights reserved.

Short-term carbon cycling responses of a mature eucalypt woodland to gradual stepwise enrichment of atmospheric CO2 concentration.

PubMed

Drake, John E; Macdonald, Catriona A; Tjoelker, Mark G; Crous, Kristine Y; Gimeno, Teresa E; Singh, Brajesh K; Reich, Peter B; Anderson, Ian C; Ellsworth, David S

2016-01-01

Projections of future climate are highly sensitive to uncertainties regarding carbon (C) uptake and storage by terrestrial ecosystems. The Eucalyptus Free-Air CO2 Enrichment (EucFACE) experiment was established to study the effects of elevated atmospheric CO2 concentrations (eCO2 ) on a native mature eucalypt woodland with low fertility soils in southeast Australia. In contrast to other FACE experiments, the concentration of CO2 at EucFACE was increased gradually in steps above ambient (+0, 30, 60, 90, 120, and 150 ppm CO2 above ambient of ~400 ppm), with each step lasting approximately 5 weeks. This provided a unique opportunity to study the short-term (weeks to months) response of C cycle flux components to eCO2 across a range of CO2 concentrations in an intact ecosystem. Soil CO2 efflux (i.e., soil respiration or Rsoil ) increased in response to initial enrichment (e.g., +30 and +60 ppm CO2 ) but did not continue to increase as the CO2 enrichment was stepped up to higher concentrations. Light-saturated photosynthesis of canopy leaves (Asat ) also showed similar stimulation by elevated CO2 at +60 ppm as at +150 ppm CO2 . The lack of significant effects of eCO2 on soil moisture, microbial biomass, or activity suggests that the increase in Rsoil likely reflected increased root and rhizosphere respiration rather than increased microbial decomposition of soil organic matter. This rapid increase in Rsoil suggests that under eCO2, additional photosynthate was produced, transported belowground, and respired. The consequences of this increased belowground activity and whether it is sustained through time in mature ecosystems under eCO2 are a priority for future research. © 2015 John Wiley & Sons Ltd.

Efficacies of biochar and biochar-based amendment on vegetable yield and nitrogen utilization in four consecutive planting seasons.

PubMed

Wang, Hefang; Zheng, Hao; Jiang, Zhixiang; Dai, Yanhui; Liu, Guocheng; Chen, Lei; Luo, Xianxiang; Liu, Minhui; Wang, Zhenyu

2017-09-01

Biochar has been suggested as a potential tailored technology for mediating soil conditions and improving crop yields. However, the efficacies of biochar and biochar-based amendments (e.g., composted biochar) in agricultural soils under a rotation system remain uncertain. In this study, an arable soil was subjected to peanut shell biochar (PBC) and biochar-based amendment (PAD) combined with or without nitrogen (N) fertilizer to evaluate their effects on vegetable yield, N bioavailability, and their relative contribution to vegetable biomass in four consecutive planting seasons. PBC alone or in co-application with N fertilizer had little effect on vegetable yield, while PAD co-application with N fertilizer decreased vegetable biomass because of the inhibition of root morphology by excessive nutrient supply. PBC and PAD applications increased rhizosphere soil pH due to OH - and HCO 3 - release and NO 3 - -N uptake. Although the addition of PAD increased soil N contents due to its high contents in PAD, it had little effects on N utilization efficiency (NUE) in the four seasons. The relative contribution of PBC, PAD, and their interaction with N fertilizer to biomass yield was maintained at a low level. Our results indicated that a biochar-based amendment (e.g., PAD) was a potential alternative to N fertilizer, but the ratio of biochar to additives should be managed carefully to generate optimal benefits. Notably, the efficacy of PAD on plant growth was closely associated with plant species, and further related research on different plants is encouraged. Copyright © 2017. Published by Elsevier B.V.

Impacts of integrated nutrient management on methane emission, global warming potential and carbon storage capacity in rice grown in a northeast India soil.

PubMed

Bharali, Ashmita; Baruah, Kushal Kumar; Baruah, Sunitee Gohain; Bhattacharyya, Pradip

2018-02-01

Rice soil is a source of emission of two major greenhouse gases (methane (CH 4 ) and nitrous oxide (N 2 O)) and a sink of carbon dioxide (CO 2 ). The effect of inorganic fertilizers in combination with various organics (cow dung, green manure (Sesbania aculeata) Azolla compost, rice husk) on CH 4 emission, global warming potential, and soil carbon storage along with crop productivity were studied at university farm under field conditions. The experiment was conducted in a randomized block design for 2 years in a monsoon rice (cv. Ranjit) ecosystem (June-November, 2014 and 2015). Combined application of inorganic (NPK) with Sesbania aculeata resulted in high global warming potential (GWP) of 887.4 kg CO 2 ha -1 and low GWP of 540.6 kg CO 2 ha -1 was recorded from inorganic fertilizer applied field. Irrespective of the type of organic amendments, flag leaf photosynthesis of the rice crop increased over NPK application (control). There was an increase in CH 4 emission from the organic amended fields compared to NPK alone. The combined application of NPK and Azolla compost was effective in the buildup of soil carbon (16.93 g kg -1 ) and capacity of soil carbon storage (28.1 Mg C ha -1 ) with high carbon efficiency ratio (16.9). Azolla compost application along with NPK recorded 15.66% higher CH 4 emission with 27.43% yield increment over control. Azolla compost application significantly enhanced carbon storage of soil and improved the yielding ability of grain (6.55 Mg ha -1 ) over other treatments.

Greenhouse gas emissions under conservation agriculture compared to traditional cultivation of maize in the central highlands of Mexico.

PubMed

Dendooven, Luc; Gutiérrez-Oliva, Vicente F; Patiño-Zúñiga, Leonardo; Ramírez-Villanueva, Daniel A; Verhulst, Nele; Luna-Guido, Marco; Marsch, Rodolfo; Montes-Molina, Joaquín; Gutiérrez-Miceli, Federico A; Vásquez-Murrieta, Soledad; Govaerts, Bram

2012-08-01

In 1991, the 'International Maize and Wheat Improvement Center' (CIMMYT) started a field experiment in the rain fed Mexican highlands to investigate conservation agriculture (CA) as a sustainable alternative for conventional maize production practices (CT). CT techniques, characterized by deep tillage, monoculture and crop residue removal, have deteriorated soil fertility and reduced yields. CA, which combines minimum tillage, crop rotations and residue retention, restores soil fertility and increases yields. Soil organic matter increases in CA compared to CT, but increases in greenhouse gas emissions (GHG) in CA might offset the gains obtained to mitigate global warming. Therefore, CO(2), CH(4) and N(2)O emissions, soil temperature, C and water content were monitored in CA and CT treatments in 2010-2011. The cumulative GHG emitted were similar for CA and CT in both years, but the C content in the 0-60 cm layer was higher in CA (117.7 Mg C ha(-1)) than in CT (69.7 Mg C ha(-1)). The net global warming potential (GWP) of CA (considering soil C sequestration, GHG emissions, fuel use, and fertilizer and seeds production) was -7729 kg CO(2) ha(-1) y(-1) in 2008-2009 and -7892 kg CO(2) ha(-1) y(-1) in 2010-2011, whereas that of CT was 1327 and 1156 kg CO(2) ha(-1) y(-1). It was found that the contribution of CA to GWP was small compared to that of CT. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of cover crops on greenhouse gas emissions in an irrigated field under integrated soil fertility management

NASA Astrophysics Data System (ADS)

Guardia, Guillermo; Abalos, Diego; García-Marco, Sonia; Quemada, Miguel; Alonso-Ayuso, María; Cárdenas, Laura M.; Dixon, Elizabeth R.; Vallejo, Antonio

2016-09-01

Agronomical and environmental benefits are associated with replacing winter fallow by cover crops (CCs). Yet, the effect of this practice on nitrous oxide (N2O) emissions remains poorly understood. In this context, a field experiment was carried out under Mediterranean conditions to evaluate the effect of replacing the traditional winter fallow (F) by vetch (Vicia sativa L.; V) or barley (Hordeum vulgare L.; B) on greenhouse gas (GHG) emissions during the intercrop and the maize (Zea mays L.) cropping period. The maize was fertilized following integrated soil fertility management (ISFM) criteria. Maize nitrogen (N) uptake, soil mineral N concentrations, soil temperature and moisture, dissolved organic carbon (DOC) and GHG fluxes were measured during the experiment. Our management (adjusted N synthetic rates due to ISFM) and pedo-climatic conditions resulted in low cumulative N2O emissions (0.57 to 0.75 kg N2O-N ha-1 yr-1), yield-scaled N2O emissions (3-6 g N2O-N kg aboveground N uptake-1) and N surplus (31 to 56 kg N ha-1) for all treatments. Although CCs increased N2O emissions during the intercrop period compared to F (1.6 and 2.6 times in B and V, respectively), the ISFM resulted in similar cumulative emissions for the CCs and F at the end of the maize cropping period. The higher C : N ratio of the B residue led to a greater proportion of N2O losses from the synthetic fertilizer in these plots when compared to V. No significant differences were observed in CH4 and CO2 fluxes at the end of the experiment. This study shows that the use of both legume and nonlegume CCs combined with ISFM could provide, in addition to the advantages reported in previous studies, an opportunity to maximize agronomic efficiency (lowering synthetic N requirements for the subsequent cash crop) without increasing cumulative or yield-scaled N2O losses.

Causes of ice age intensification across the Mid-Pleistocene Transition

PubMed Central

Foster, Gavin L.; Rohling, Eelco J.; Sexton, Philip F.; Cherry, Soraya G.; Hasenfratz, Adam P.; Haug, Gerald H.; Martínez-García, Alfredo; Pälike, Heiko; Pancost, Richard D.; Wilson, Paul A.

2017-01-01

During the Mid-Pleistocene Transition (MPT; 1,200–800 kya), Earth’s orbitally paced ice age cycles intensified, lengthened from ∼40,000 (∼40 ky) to ∼100 ky, and became distinctly asymmetrical. Testing hypotheses that implicate changing atmospheric CO2 levels as a driver of the MPT has proven difficult with available observations. Here, we use orbitally resolved, boron isotope CO2 data to show that the glacial to interglacial CO2 difference increased from ∼43 to ∼75 μatm across the MPT, mainly because of lower glacial CO2 levels. Through carbon cycle modeling, we attribute this decline primarily to the initiation of substantive dust-borne iron fertilization of the Southern Ocean during peak glacial stages. We also observe a twofold steepening of the relationship between sea level and CO2-related climate forcing that is suggestive of a change in the dynamics that govern ice sheet stability, such as that expected from the removal of subglacial regolith or interhemispheric ice sheet phase-locking. We argue that neither ice sheet dynamics nor CO2 change in isolation can explain the MPT. Instead, we infer that the MPT was initiated by a change in ice sheet dynamics and that longer and deeper post-MPT ice ages were sustained by carbon cycle feedbacks related to dust fertilization of the Southern Ocean as a consequence of larger ice sheets. PMID:29180424

Covariation of deep Southern Ocean oxygenation and atmospheric CO2 through the last ice age.

PubMed

Jaccard, Samuel L; Galbraith, Eric D; Martínez-García, Alfredo; Anderson, Robert F

2016-02-11

No single mechanism can account for the full amplitude of past atmospheric carbon dioxide (CO2) concentration variability over glacial-interglacial cycles. A build-up of carbon in the deep ocean has been shown to have occurred during the Last Glacial Maximum. However, the mechanisms responsible for the release of the deeply sequestered carbon to the atmosphere at deglaciation, and the relative importance of deep ocean sequestration in regulating millennial-timescale variations in atmospheric CO2 concentration before the Last Glacial Maximum, have remained unclear. Here we present sedimentary redox-sensitive trace-metal records from the Antarctic Zone of the Southern Ocean that provide a reconstruction of transient changes in deep ocean oxygenation and, by inference, respired carbon storage throughout the last glacial cycle. Our data suggest that respired carbon was removed from the abyssal Southern Ocean during the Northern Hemisphere cold phases of the deglaciation, when atmospheric CO2 concentration increased rapidly, reflecting--at least in part--a combination of dwindling iron fertilization by dust and enhanced deep ocean ventilation. Furthermore, our records show that the observed covariation between atmospheric CO2 concentration and abyssal Southern Ocean oxygenation was maintained throughout most of the past 80,000 years. This suggests that on millennial timescales deep ocean circulation and iron fertilization in the Southern Ocean played a consistent role in modifying atmospheric CO2 concentration.

Causes of ice age intensification across the Mid-Pleistocene Transition

NASA Astrophysics Data System (ADS)

Chalk, Thomas B.; Hain, Mathis P.; Foster, Gavin L.; Rohling, Eelco J.; Sexton, Philip F.; Badger, Marcus P. S.; Cherry, Soraya G.; Hasenfratz, Adam P.; Haug, Gerald H.; Jaccard, Samuel L.; Martínez-García, Alfredo; Pälike, Heiko; Pancost, Richard D.; Wilson, Paul A.

2017-12-01

During the Mid-Pleistocene Transition (MPT; 1,200–800 kya), Earth's orbitally paced ice age cycles intensified, lengthened from ˜40,000 (˜40 ky) to ˜100 ky, and became distinctly asymmetrical. Testing hypotheses that implicate changing atmospheric CO2 levels as a driver of the MPT has proven difficult with available observations. Here, we use orbitally resolved, boron isotope CO2 data to show that the glacial to interglacial CO2 difference increased from ˜43 to ˜75 μatm across the MPT, mainly because of lower glacial CO2 levels. Through carbon cycle modeling, we attribute this decline primarily to the initiation of substantive dust-borne iron fertilization of the Southern Ocean during peak glacial stages. We also observe a twofold steepening of the relationship between sea level and CO2-related climate forcing that is suggestive of a change in the dynamics that govern ice sheet stability, such as that expected from the removal of subglacial regolith or interhemispheric ice sheet phase-locking. We argue that neither ice sheet dynamics nor CO2 change in isolation can explain the MPT. Instead, we infer that the MPT was initiated by a change in ice sheet dynamics and that longer and deeper post-MPT ice ages were sustained by carbon cycle feedbacks related to dust fertilization of the Southern Ocean as a consequence of larger ice sheets.

Estimating the risk of Amazonian forest dieback.

PubMed

Rammig, Anja; Jupp, Tim; Thonicke, Kirsten; Tietjen, Britta; Heinke, Jens; Ostberg, Sebastian; Lucht, Wolfgang; Cramer, Wolfgang; Cox, Peter

2010-08-01

*Climate change will very likely affect most forests in Amazonia during the course of the 21st century, but the direction and intensity of the change are uncertain, in part because of differences in rainfall projections. In order to constrain this uncertainty, we estimate the probability for biomass change in Amazonia on the basis of rainfall projections that are weighted by climate model performance for current conditions. *We estimate the risk of forest dieback by using weighted rainfall projections from 24 general circulation models (GCMs) to create probability density functions (PDFs) for future forest biomass changes simulated by a dynamic vegetation model (LPJmL). *Our probabilistic assessment of biomass change suggests a likely shift towards increasing biomass compared with nonweighted results. Biomass estimates range between a gain of 6.2 and a loss of 2.7 kg carbon m(-2) for the Amazon region, depending on the strength of CO(2) fertilization. *The uncertainty associated with the long-term effect of CO(2) is much larger than that associated with precipitation change. This underlines the importance of reducing uncertainties in the direct effects of CO(2) on tropical ecosystems.

Impacts of reactive nitrogen on climate change in China

PubMed Central

Shi, Yalan; Cui, Shenghui; Ju, Xiaotang; Cai, Zucong; Zhu, Yong-Guan

2015-01-01

China is mobilizing the largest anthropogenic reactive nitrogen (Nr) in the world due to agricultural, industrial and urban development. However, the climate effects related to Nr in China remain largely unclear. Here we comprehensively estimate that the net climate effects of Nr are −100 ± 414 and 322 ± 163 Tg CO2e on a GTP20 and a GTP100 basis, respectively. Agriculture contributes to warming at 187 ± 108 and 186 ± 56 Tg CO2e on a 20-y and 100-y basis, respectively, dominated by long-lived nitrous oxide (N2O) from fertilized soils. On a 20-y basis, industry contributes to cooling at −287 ± 306 Tg CO2e, largely owing to emissions of nitrogen oxides (NOx) altering tropospheric ozone, methane and aerosol concentrations. However, these effects are short-lived. The effect of industry converts to warming at 136 ± 107 Tg CO2e on a 100-y basis, mainly as a result of the reduced carbon (C) sink from the NOx-induced ozone effect on plant damage. On balance, the warming effects of gaseous Nr are partly offset by the cooling effects of N-induced carbon sequestration in terrestrial ecosystems. The large mitigation potentials through reductions in agricultural N2O and industrial NOx will accompany by a certain mitigation pressure from limited N-induced C sequestration in the future. PMID:25631557

Individual variability in reproductive success determines winners and losers under ocean acidification: a case study with sea urchins.

PubMed

Schlegel, Peter; Havenhand, Jon N; Gillings, Michael R; Williamson, Jane E

2012-01-01

Climate change will lead to intense selection on many organisms, particularly during susceptible early life stages. To date, most studies on the likely biotic effects of climate change have focused on the mean responses of pooled groups of animals. Consequently, the extent to which inter-individual variation mediates different selection responses has not been tested. Investigating this variation is important, since some individuals may be preadapted to future climate scenarios. We examined the effect of CO(2)-induced pH changes ("ocean acidification") in sperm swimming behaviour on the fertilization success of the Australasian sea urchin Heliocidaris erythrogramma, focusing on the responses of separate individuals and pairs. Acidification significantly decreased the proportion of motile sperm but had no effect on sperm swimming speed. Subsequent fertilization experiments showed strong inter-individual variation in responses to ocean acidification, ranging from a 44% decrease to a 14% increase in fertilization success. This was partly explained by the significant relationship between decreases in percent sperm motility and fertilization success at ΔpH = 0.3, but not at ΔpH = 0.5. The effects of ocean acidification on reproductive success varied markedly between individuals. Our results suggest that some individuals will exhibit enhanced fertilization success in acidified oceans, supporting the concept of 'winners' and 'losers' of climate change at an individual level. If these differences are heritable it is likely that ocean acidification will lead to selection against susceptible phenotypes as well as to rapid fixation of alleles that allow reproduction under more acidic conditions. This selection may ameliorate the biotic effects of climate change if taxa have sufficient extant genetic variation upon which selection can act.

Individual Variability in Reproductive Success Determines Winners and Losers under Ocean Acidification: A Case Study with Sea Urchins

PubMed Central

Schlegel, Peter; Havenhand, Jon N.; Gillings, Michael R.; Williamson, Jane E.

2012-01-01

Background Climate change will lead to intense selection on many organisms, particularly during susceptible early life stages. To date, most studies on the likely biotic effects of climate change have focused on the mean responses of pooled groups of animals. Consequently, the extent to which inter-individual variation mediates different selection responses has not been tested. Investigating this variation is important, since some individuals may be preadapted to future climate scenarios. Methodology/Principal Findings We examined the effect of CO2-induced pH changes (“ocean acidification”) in sperm swimming behaviour on the fertilization success of the Australasian sea urchin Heliocidaris erythrogramma, focusing on the responses of separate individuals and pairs. Acidification significantly decreased the proportion of motile sperm but had no effect on sperm swimming speed. Subsequent fertilization experiments showed strong inter-individual variation in responses to ocean acidification, ranging from a 44% decrease to a 14% increase in fertilization success. This was partly explained by the significant relationship between decreases in percent sperm motility and fertilization success at ΔpH = 0.3, but not at ΔpH = 0.5. Conclusions and Significance The effects of ocean acidification on reproductive success varied markedly between individuals. Our results suggest that some individuals will exhibit enhanced fertilization success in acidified oceans, supporting the concept of ‘winners’ and ‘losers’ of climate change at an individual level. If these differences are heritable it is likely that ocean acidification will lead to selection against susceptible phenotypes as well as to rapid fixation of alleles that allow reproduction under more acidic conditions. This selection may ameliorate the biotic effects of climate change if taxa have sufficient extant genetic variation upon which selection can act. PMID:23300876

Millennial-scale variability in dust deposition, marine export production, and nutrient consumption in the glacial subantarctic ocean (Invited)

NASA Astrophysics Data System (ADS)

Martinez-Garcia, A.; Sigman, D. M.; Anderson, R. F.; Ren, H. A.; Hodell, D. A.; Straub, M.; Jaccard, S.; Eglinton, T. I.; Haug, G. H.

2013-12-01

Based on the limitation of modern Southern Ocean phytoplankton by iron and the evidence of higher iron-bearing dust fluxes to the ocean during ice ages, it has been proposed that iron fertilization of Southern Ocean phytoplankton contributed to the reduction in atmospheric CO2 during ice ages. In the Subantarctic zone of the Atlantic Southern Ocean, glacial increases in dust flux and export production have been documented, supporting the iron fertilization hypothesis. However, these observations could be interpreted alternatively as resulting from the equatorward migration of Southern Ocean fronts during ice ages if the observed productivity rise was not accompanied by an increase in major nutrient consumption. Here, new 230Th-normalized lithogenic and opal fluxes are combined with high-resolution biomarker measurements to reconstruct millennial-scale changes in dust deposition and marine export production in the subantarctic Atlantic over the last glacial cycle. In the same record foraminifera-bound nitrogen isotopes are used to reconstruct ice age changes in surface nitrate utilization, providing a comprehensive test of the iron fertilization hypothesis. Elevation in foraminifera-bound δ15N, indicating more complete nitrate consumption, coincides with times of surface cooling and greater dust flux and export production. These observations indicate that the ice age Subantarctic was characterized by iron fertilized phytoplankton growth. The resulting strengthening of the Southern Ocean's biological pump can explain the ~40 ppm lowering of CO2 that characterizes the transitions from mid-climate states to full ice age conditions as well as the millennial-scale atmospheric CO2 fluctuations observed within the last ice age

Atmospheric deposition, CO2, and change in the land carbon sink.

PubMed

Fernández-Martínez, M; Vicca, S; Janssens, I A; Ciais, P; Obersteiner, M; Bartrons, M; Sardans, J; Verger, A; Canadell, J G; Chevallier, F; Wang, X; Bernhofer, C; Curtis, P S; Gianelle, D; Grünwald, T; Heinesch, B; Ibrom, A; Knohl, A; Laurila, T; Law, B E; Limousin, J M; Longdoz, B; Loustau, D; Mammarella, I; Matteucci, G; Monson, R K; Montagnani, L; Moors, E J; Munger, J W; Papale, D; Piao, S L; Peñuelas, J

2017-08-29

Concentrations of atmospheric carbon dioxide (CO 2 ) have continued to increase whereas atmospheric deposition of sulphur and nitrogen has declined in Europe and the USA during recent decades. Using time series of flux observations from 23 forests distributed throughout Europe and the USA, and generalised mixed models, we found that forest-level net ecosystem production and gross primary production have increased by 1% annually from 1995 to 2011. Statistical models indicated that increasing atmospheric CO 2 was the most important factor driving the increasing strength of carbon sinks in these forests. We also found that the reduction of sulphur deposition in Europe and the USA lead to higher recovery in ecosystem respiration than in gross primary production, thus limiting the increase of carbon sequestration. By contrast, trends in climate and nitrogen deposition did not significantly contribute to changing carbon fluxes during the studied period. Our findings support the hypothesis of a general CO 2 -fertilization effect on vegetation growth and suggest that, so far unknown, sulphur deposition plays a significant role in the carbon balance of forests in industrialized regions. Our results show the need to include the effects of changing atmospheric composition, beyond CO 2 , to assess future dynamics of carbon-climate feedbacks not currently considered in earth system/climate modelling.

Soil CO2 evolution and root respiration in 11 year-old Loblolly Pine (Pinus taeda) Plantations as Affected by Moisture and Nutrient Availability

Treesearch

Chris A. Maier; L.W. Kress

2000-01-01

We measured soil CO2 evolution rates with (Sff) and without (Sms) the forest floor litter and root respiration monthly in 11-year-old loblolly pine (Pinus taeda L.) plantations during the fourth year of fertilization and irrigation treatments. Values of Sff...

Long-term CO2 fertilization increases vegetation productivity and has little effect on hydrological partitioning in tropical rainforests

NASA Astrophysics Data System (ADS)

Yang, Yuting; Donohue, Randall J.; McVicar, Tim R.; Roderick, Michael L.; Beck, Hylke E.

2016-08-01

Understanding how tropical rainforests respond to elevated atmospheric CO2 concentration (eCO2) is essential for predicting Earth's carbon, water, and energy budgets under future climate change. Here we use long-term (1982-2010) precipitation (P) and runoff (Q) measurements to infer runoff coefficient (Q/P) and evapotranspiration (E) trends across 18 unimpaired tropical rainforest catchments. We complement that analysis by using satellite observations coupled with ecosystem process modeling (using both "top-down" and "bottom-up" perspectives) to examine trends in carbon uptake and relate that to the observed changes in Q/P and E. Our results show there have been only minor changes in the satellite-observed canopy leaf area over 1982-2010, suggesting that eCO2 has not increased vegetation leaf area in tropical rainforests and therefore any plant response to eCO2 occurs at the leaf level. Meanwhile, observed Q/P and E also remained relatively constant in the 18 catchments, implying an unchanged hydrological partitioning and thus approximately conserved transpiration under eCO2. For the same period, using a top-down model based on gas exchange theory, we predict increases in plant assimilation (A) and light use efficiency (ɛ) at the leaf level under eCO2, the magnitude of which is essentially that of eCO2 (i.e., 12% over 1982-2010). Simulations from 10 state-of-the-art bottom-up ecosystem models over the same catchments also show that the direct effect of eCO2 is to mostly increase A and ɛ with little impact on E. Our findings add to the current limited pool of knowledge regarding the long-term eCO2 impacts in tropical rainforests.

Impacts of Fertilization Regimes on Arbuscular Mycorrhizal Fungal (AMF) Community Composition Were Correlated with Organic Matter Composition in Maize Rhizosphere Soil

PubMed Central

Zhu, Chen; Ling, Ning; Guo, Junjie; Wang, Min; Guo, Shiwei; Shen, Qirong

2016-01-01

The understanding of the response of arbuscular mycorrhizal fungi (AMF) community composition to fertilization is of great significance in sustainable agriculture. However, how fertilization influences AMF diversity and composition is not well-established yet. A field experiment located in northeast China in typical black soil (Chernozem) was conducted and high-throughput sequencing approach was used to investigate the effects of different fertilizations on the variation of AMF community in the rhizosphere soil of maize crop. The results showed that AMF diversity in the maize rhizosphere was significantly altered by different fertilization regimes. As revealed by redundancy analysis, the application of organic manure was the most important factor impacting AMF community composition between samples with and without organic manure, followed by N fertilizer and P fertilizer inputs. Moreover, the organic matter composition in the rhizosphere, determined by GC–MS, was significantly altered by the organic manure amendment. Many of the chemical components displayed significant relationships with the AMF community composition according to the Mantel test, among those, 2-ethylnaphthalene explained the highest percentage (54.2%) of the variation. The relative contents of 2-ethylnaphthalene and 2, 6, 10-trimethyltetradecane had a negative correlation with Glomus relative abundance, while the relative content of 3-methylbiphenyl displayed a positive correlation with Rhizophagus. The co-occurrence patterns in treatments with and without organic manure amendment were analyzed, and more hubs were detected in the network of soils with organic manure amendment. Additionally, three operational taxonomic units (OTUs) belonging to Glomerales were identified as hubs in all treatments, indicating these OTUs likely occupied broad ecological niches and were always active for mediating AMF species interaction in the maize rhizosphere. Taken together, impacts of fertilization regimes on AMF community composition were correlated with organic matter composition in maize rhizosphere soil and the application of manure could activate more AMF species to interact with other species in the maize rhizosphere. This knowledge can be valuable in regulating the symbiotic system of plants and AMF, maintaining the health and high yields of crops and providing a primary basis for rational fertilization. PMID:27899920

Soil-atmosphere trace gas exchange from tropical oil palm plantations on peat

NASA Astrophysics Data System (ADS)

Arn Teh, Yit; Manning, Frances; Zin Zawawi, Norliyana; Hill, Timothy; Chocholek, Melanie; Khoon Kho, Lip

2015-04-01

Oil palm is the largest agricultural crop in the tropics, accounting for 13 % of all tropical land cover. Due to its large areal extent, oil palm cultivation may have important implications not only for terrestrial stores of C and N, but may also impact regional and global exchanges of material and energy, including fluxes of trace gases and water vapor. In particular, recent expansion of oil palm into tropical peatlands has raised concerns over enhanced soil C emissions from degradation of peat, and elevated N-gas fluxes linked to N fertilizer application. Here we report our preliminary findings on soil carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes from a long-term, multi-scale project investigating the C, N and greenhouse gas (GHG) dynamics of oil palm ecosystems established on peat soils in Sarawak, Malaysian Borneo. Flux chamber measurements indicate that soil CO2, CH4 and N2O fluxes averaged 20.0 ± 16.0 Mg CO2-C ha-1 yr-1, 37.4 ± 29.9 kg CH4-C ha-1 yr-1 and 4.7 ± 4.2 g N2O-N ha-1 yr-1, respectively. Soil CO2 fluxes were on par with other drained tropical peatlands; whereas CH4 fluxes exceeded observations from similar study sites elsewhere. Nitrous oxide fluxes were in a similar range to fluxes from other drained tropical peatlands, but lower than emissions from mineral-soil plantations by up to three orders of magnitude. Fluxes of soil CO2 and N2O were spatially stratified, and contingent upon the distribution of plants, deposited harvest residues, and soil moisture. Soil CO2 fluxes were most heavily influenced by the distribution of palms and their roots. On average, autotrophic (root) respiration accounted for approximately 78 % of total soil CO2 flux, and total soil respiration declined steeply away from palms; e.g. soil CO2 fluxes in the immediate 1 m radius around palms were up to 6 times greater than fluxes in inter-palm spaces due to higher densities of roots. Placement of harvest residues played an important - but secondary - role in modulating soil CO2 fluxes; soil respiration rates doubled in areas where harvest residues were deposited, reflecting an enhanced input of labile organic matter for decomposition. In contrast, N2O fluxes were best-predicted by the distribution of harvest residues, and were only weakly related to plant distributions or soil moisture. For example, N2O fluxes from harvest residue piles were up to twice of the overall plot-average. In contrast, N2O fluxes showed no clear pattern around palms or in inter-palm spaces; this finding is surprising because N fertilizers are applied within the 1 m radius around palms, and we expected to observe enhanced N2O fluxes in areas of greater fertilizer input. This suggests that palms may be a strong competitor for N in these ecosystems, and that fertilizer application may more closely match overall plant demand than in mineral-soil plantations. Overall, the spatial patterning of soil CO2 and N2O fluxes implies that soil biogeochemical processes are predictably distributed in space, potentially making it easier to model and constrain fluxes of these soil-derived GHGs.

Inoculation of soil native cyanobacteria to restore arid degraded soils

NASA Astrophysics Data System (ADS)

Raúl Román Fernández, José; Roncero Ramos, Beatriz; Chamizo de la Piedra, Sonia; Rodríguez Caballero, Emilio; Ángeles Muñoz Martín, M.; Mateo, Pilar; Cantón Castilla, Yolanda

2017-04-01

Restoration projects in semiarid lands often yield poor results. Water scarcity, low soil fertility, and poor soil structure strongly limit the survival and growth of planted seedlings in these areas. Under these conditions, a previous stage that improves edaphic conditions would turn out to a successful plant restoration. By successfully colonizing arid soils, cyanobacteria naturally provide suitable edaphic conditions, enhancing water availability, soil fertility and soil stability. Furthermore, cyanobacteria can be easily isolated and cultured ex-situ to produce high quantities of biomass, representing a potential tool to restore large areas efficiently. The objective of this study was to test the effect of inoculated cyanobacteria on degraded soils at three different semiarid areas from southeast Spain: Tabernas badlands, a limestone quarry located in Gádor, and grazed grassland in Las Amoladeras (Cabo de Gata). Soil native cyanobacteria belonging to three representative N-fixing genera (Nostoc, Scytonema and Tolypothrix) were isolated from such soils and cultured in BG110 medium. Each strain was inoculated (6 g m-2), separately and mixed (all in the same proportion), on Petri dishes with 80 g of each soil. Biocrust development was monitored during 3 months in these soils under laboratory conditions, at a constant temperature of 25oC. During the experiment, two irrigation treatments were applied simulating a dry (180 mm) and a wet (360 mm) rainfall year (average recorded in the study sites). After 3 months, net CO2 flux, spectral response and soil surface microtopography (1 mm spatial resolution) of inoculated and control soils was measured under wet conditions, all of them as a surrogate of biocrust development. Samples of the surface crust were collected in order to determine total soil organic carbon (SOC) content. The inoculated soils showed positive values of net CO2 flux, thus indicating a net CO2 uptake, whereas control soils showed CO2 fluxes closed to zero. This higher CO2 fixation in the inoculated soils was reflected in the higher SOC content found in these soils with respect to the non-inoculated soils. Soil surface roughness increased with biocrust development in the inoculated soils as compared to control soils. From the different treatments, soil inoculation with the mixture of the three strains promoted the highest SOC contents and absorbance at 680 nm (indicative of higher chlorophyll a content) on the three soil types. Therefore, using a consortium of cyanobacteria to inoculate degraded soils seems to be a more promising strategy to restore soils than inoculating individual species. Finally, differences between irrigation treatments were no significant, suggesting that water availability was not a key driver for cyanobacteria development under control laboratory conditions. Our results underline the viability of cyanobacteria inoculation to form an artificial developed biocrust that contribute to CO2 uptake and increase soil fertility which could facilitate further plant cover establishment. However, more studies are necessaries to test the effectiveness of inoculated crust development under field conditions.

Soil Management Effects on Gas Fluxes from an Organic Soil Agricultural System

NASA Astrophysics Data System (ADS)

Jennewein, S. P.; Bhadha, J. H.; Lang, T. A.; Singh, M.; Daroub, S. H.; McCray, M.

2015-12-01

The role of soil management on gas flux isn't well understood for Histosols of the Everglades Agricultural Area (EAA) of southern Florida. The region is responsible for roughly half of sugarcane (Saccharum spp. hybrids) production in the USA along with supplying winter vegetable crops to the eastern USA. Future productivity in the EAA is jeopardized by soil subsidence resulting from oxidation of organic matter. Establishing the role of tillage, water-table depth, nitrogen fertilizer, and soil depth on gas flux will help determine how effective various managements are on conserving soil. Ongoing lysimeter and field studies examined effects of management practices (water-table, tillage, and nitrogen fertilizer), and soil depth on, gas emission and microbial biomass. The trials were set in Belle Glade, FL, on Lauderhill muck (Lithic Haplosaprists). Results to be presented include soil microbial biomass and soil gas (CO2, CH4, and N2O) flux. This study provides insight into management effectiveness and agriculture sustainability on shallow muck soils of the EAA and will help farmers mitigate problems associated with soil subsidence and seasonally high water-tables.

Comparison greenhouse gas (GHG) emissions and global warming potential (GWP) effect of energy use in different wheat agroecosystems in Iran.

PubMed

Yousefi, Mohammad; Mahdavi Damghani, Abdolmajid; Khoramivafa, Mahmud

2016-04-01

The aims of this study were to determine energy requirement and global warming potential (GWP) in low and high input wheat production systems in western of Iran. For this purpose, data were collected from 120 wheat farms applying questionnaires via face-to-face interviews. Results showed that total energy input and output were 60,000 and 180,000 MJ ha(-1) in high input systems and 14,000 and 56,000 MJ ha(-1) in low input wheat production systems, respectively. The highest share of total input energy in high input systems recorded for electricity power, N fertilizer, and diesel fuel with 36, 18, and 13 %, respectively, while the highest share of input energy in low input systems observed for N fertilizer, diesel fuel, and seed with 32, 31, and 27 %. Energy use efficiency in high input systems (3.03) was lower than of low input systems (3.94). Total CO2, N2O, and CH4 emissions in high input systems were 1981.25, 31.18, and 1.87 kg ha(-1), respectively. These amounts were 699.88, 0.02, and 0.96 kg ha(-1) in low input systems. In high input wheat production systems, total GWP was 11686.63 kg CO2eq ha(-1) wheat. This amount was 725.89 kg CO2eq ha(-1) in low input systems. The results show that 1 ha of high input system will produce greenhouse effect 17 times of low input systems. So, high input production systems need to have an efficient and sustainable management for reducing environmental crises such as change climate.

The PTK7-Related Transmembrane Proteins Off-track and Off-track 2 Are Co-receptors for Drosophila Wnt2 Required for Male Fertility

PubMed Central

Honemann-Capito, Mona; Brechtel-Curth, Katja; Hedderich, Marie; Wodarz, Andreas

2014-01-01

Wnt proteins regulate many developmental processes and are required for tissue homeostasis in adult animals. The cellular responses to Wnts are manifold and are determined by the respective Wnt ligand and its specific receptor complex in the plasma membrane. Wnt receptor complexes contain a member of the Frizzled family of serpentine receptors and a co-receptor, which commonly is a single-pass transmembrane protein. Vertebrate protein tyrosine kinase 7 (PTK7) was identified as a Wnt co-receptor required for control of planar cell polarity (PCP) in frogs and mice. We found that flies homozygous for a complete knock-out of the Drosophila PTK7 homolog off track (otk) are viable and fertile and do not show PCP phenotypes. We discovered an otk paralog (otk2, CG8964), which is co-expressed with otk throughout embryonic and larval development. Otk and Otk2 bind to each other and form complexes with Frizzled, Frizzled2 and Wnt2, pointing to a function as Wnt co-receptors. Flies lacking both otk and otk2 are viable but male sterile due to defective morphogenesis of the ejaculatory duct. Overexpression of Otk causes female sterility due to malformation of the oviduct, indicating that Otk and Otk2 are specifically involved in the sexually dimorphic development of the genital tract. PMID:25010066

The PTK7-related transmembrane proteins off-track and off-track 2 are co-receptors for Drosophila Wnt2 required for male fertility.

PubMed

Linnemannstöns, Karen; Ripp, Caroline; Honemann-Capito, Mona; Brechtel-Curth, Katja; Hedderich, Marie; Wodarz, Andreas

2014-07-01

Wnt proteins regulate many developmental processes and are required for tissue homeostasis in adult animals. The cellular responses to Wnts are manifold and are determined by the respective Wnt ligand and its specific receptor complex in the plasma membrane. Wnt receptor complexes contain a member of the Frizzled family of serpentine receptors and a co-receptor, which commonly is a single-pass transmembrane protein. Vertebrate protein tyrosine kinase 7 (PTK7) was identified as a Wnt co-receptor required for control of planar cell polarity (PCP) in frogs and mice. We found that flies homozygous for a complete knock-out of the Drosophila PTK7 homolog off track (otk) are viable and fertile and do not show PCP phenotypes. We discovered an otk paralog (otk2, CG8964), which is co-expressed with otk throughout embryonic and larval development. Otk and Otk2 bind to each other and form complexes with Frizzled, Frizzled2 and Wnt2, pointing to a function as Wnt co-receptors. Flies lacking both otk and otk2 are viable but male sterile due to defective morphogenesis of the ejaculatory duct. Overexpression of Otk causes female sterility due to malformation of the oviduct, indicating that Otk and Otk2 are specifically involved in the sexually dimorphic development of the genital tract.

[Variation characteristics of maize yield and fertilizer utilization rate on an upland yellow soil under long term fertilization].

PubMed

Luo, Long-Zao; Li, Yu; Zhang, Wen-An; Xiao, Hou-Jun; Jiang, Tai-Ming

2013-10-01

An analysis was made on the 16-year experimental data from the long term fertilization, experiment of maize on a yellow soil in Guizhou of Southwest China. Four treatments, i. e. , no fertilization (CK), chemical fertilization (165 kg N x hm(-2), 82.5 kg P2O5 x hm(-2), and 82.5 kg K2O x hm(-2), NPK), organic manure (30555 kg x hm(-2), M), and combined applicatioin of chemical fertilizers and organic manure (NPKM), were selected to analyze the variation trends of maize yield and fertilizer use efficiency on yellow soil under effects of different long term fertilization modes, aimed to provide references for evaluating and establishing long term fertilization mode and promote the sustainable development of crop production. Overall, the maize yield under long term fertilization had an increasing trend, with a large annual variation. Treatment NPKM had the best yield-increasing effect, with the maize yield increased by 4075.71 kg x hm(-2) and the increment being up to 139.2%. Long term fertilization increased the fertilizer utilization efficiency of maize. In treatment M, the nitrogen and phosphorus utilization rates were increased significantly by 35.4% and 18.8%, respectively. Treatment NPK had obvious effect in improving potassium utilization rate, with an increment of 20% and being far higher than that in treatments M (8.7%) and NPKM (9.2%). The results showed that long term fertilization, especially the combined application of chemical fertilizers and organic manure, was of great importance in increasing crop yield and fertilizer use efficiency.

Plant growth improvement mediated by nitrate capture in co-composted biochar

PubMed Central

Kammann, Claudia I.; Schmidt, Hans-Peter; Messerschmidt, Nicole; Linsel, Sebastian; Steffens, Diedrich; Müller, Christoph; Koyro, Hans-Werner; Conte, Pellegrino; Stephen, Joseph

2015-01-01

Soil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting considerably promoted biochars’ positive effects, largely by nitrate (nutrient) capture and delivery. In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a sandy-poor soil amended with 2% (w/w) co-composted biochar (BCcomp). Conversely, addition of 2% (w/w) untreated biochar (BCpure) decreased the biomass to 60% of the control. Growth-promoting (BCcomp) as well as growth-reducing (BCpure) effects were more pronounced at lower nutrient-supply levels. Electro-ultra filtration and sequential biochar-particle washing revealed that co-composted biochar was nutrient-enriched, particularly with the anions nitrate and phosphate. The captured nitrate in BCcomp was (1) only partly detectable with standard methods, (2) largely protected against leaching, (3) partly plant-available, and (4) did not stimulate N2O emissions. We hypothesize that surface ageing plus non-conventional ion-water bonding in micro- and nano-pores promoted nitrate capture in biochar particles. Amending (N-rich) bio-waste with biochar may enhance its agronomic value and reduce nutrient losses from bio-wastes and agricultural soils. PMID:26057083

Plant growth improvement mediated by nitrate capture in co-composted biochar

NASA Astrophysics Data System (ADS)

Kammann, Claudia I.; Schmidt, Hans-Peter; Messerschmidt, Nicole; Linsel, Sebastian; Steffens, Diedrich; Müller, Christoph; Koyro, Hans-Werner; Conte, Pellegrino; Stephen, Joseph

2015-06-01

Soil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting considerably promoted biochars’ positive effects, largely by nitrate (nutrient) capture and delivery. In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a sandy-poor soil amended with 2% (w/w) co-composted biochar (BCcomp). Conversely, addition of 2% (w/w) untreated biochar (BCpure) decreased the biomass to 60% of the control. Growth-promoting (BCcomp) as well as growth-reducing (BCpure) effects were more pronounced at lower nutrient-supply levels. Electro-ultra filtration and sequential biochar-particle washing revealed that co-composted biochar was nutrient-enriched, particularly with the anions nitrate and phosphate. The captured nitrate in BCcomp was (1) only partly detectable with standard methods, (2) largely protected against leaching, (3) partly plant-available, and (4) did not stimulate N2O emissions. We hypothesize that surface ageing plus non-conventional ion-water bonding in micro- and nano-pores promoted nitrate capture in biochar particles. Amending (N-rich) bio-waste with biochar may enhance its agronomic value and reduce nutrient losses from bio-wastes and agricultural soils.

Distribution of heavy metals from flue gas in algal bioreactor

NASA Astrophysics Data System (ADS)

Napan, Katerine

Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavy metals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavy metals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavy metals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavy metals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavy metal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavy metal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavy metals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavy metals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

Disparate effects of global-change drivers on mountain conifer forests: warming-induced growth enhancement in young trees vs. CO2 fertilization in old trees from wet sites.

PubMed

Camarero, J Julio; Gazol, Antonio; Galván, Juan Diego; Sangüesa-Barreda, Gabriel; Gutiérrez, Emilia

2015-02-01

Theory predicts that the postindustrial rise in the concentration of CO2 in the atmosphere (c(a)) should enhance tree growth either through a direct fertilization effect or indirectly by improving water use efficiency in dry areas. However, this hypothesis has received little support in cold-limited and subalpine forests where positive growth responses to either rising ca or warmer temperatures are still under debate. In this study, we address this issue by analyzing an extensive dendrochronological network of high-elevation Pinus uncinata forests in Spain (28 sites, 544 trees) encompassing the whole biogeographical extent of the species. We determine if the basal area increment (BAI) trends are linked to climate warming and increased c(a) by focusing on region- and age-dependent responses. The largest improvement in BAI over the past six centuries occurred during the last 150 years affecting young trees and being driven by recent warming. Indeed, most studied regions and age classes presented BAI patterns mainly controlled by temperature trends, while growing-season precipitation was only relevant in the driest sites. Growth enhancement was linked to rising ca in mature (151-300 year-old trees) and old-mature trees (301-450 year-old trees) from the wettest sites only. This finding implies that any potential fertilization effect of elevated c(a) on forest growth is contingent on tree features that vary with ontogeny and it depends on site conditions (for instance water availability). Furthermore, we found widespread growth decline in drought-prone sites probably indicating that the rise in ca did not compensate for the reduction in water availability. Thus, warming-triggered drought stress may become a more important direct driver of growth than rising ca in similar subalpine forests. We argue that broad approaches in biogeographical and temporal terms are required to adequately evaluate any effect of rising c(a) on forest growth. © 2014 John Wiley & Sons Ltd.

A gradient of nutrient enrichment reveals nonlinear impacts of fertilization on Arctic plant diversity and ecosystem function.

PubMed

Prager, Case M; Naeem, Shahid; Boelman, Natalie T; Eitel, Jan U H; Greaves, Heather E; Heskel, Mary A; Magney, Troy S; Menge, Duncan N L; Vierling, Lee A; Griffin, Kevin L

2017-04-01

Rapid environmental change at high latitudes is predicted to greatly alter the diversity, structure, and function of plant communities, resulting in changes in the pools and fluxes of nutrients. In Arctic tundra, increased nitrogen (N) and phosphorus (P) availability accompanying warming is known to impact plant diversity and ecosystem function; however, to date, most studies examining Arctic nutrient enrichment focus on the impact of relatively large (>25x estimated naturally occurring N enrichment) doses of nutrients on plant community composition and net primary productivity. To understand the impacts of Arctic nutrient enrichment, we examined plant community composition and the capacity for ecosystem function (net ecosystem exchange, ecosystem respiration, and gross primary production) across a gradient of experimental N and P addition expected to more closely approximate warming-induced fertilization. In addition, we compared our measured ecosystem CO 2 flux data to a widely used Arctic ecosystem exchange model to investigate the ability to predict the capacity for CO 2 exchange with nutrient addition. We observed declines in abundance-weighted plant diversity at low levels of nutrient enrichment, but species richness and the capacity for ecosystem carbon uptake did not change until the highest level of fertilization. When we compared our measured data to the model, we found that the model explained roughly 30%-50% of the variance in the observed data, depending on the flux variable, and the relationship weakened at high levels of enrichment. Our results suggest that while a relatively small amount of nutrient enrichment impacts plant diversity, only relatively large levels of fertilization-over an order of magnitude or more than warming-induced rates-significantly alter the capacity for tundra CO 2 exchange. Overall, our findings highlight the value of measuring and modeling the impacts of a nutrient enrichment gradient, as warming-related nutrient availability may impact ecosystems differently than single-level fertilization experiments.

Water addition regulates the metabolic activity of ammonia oxidizers responding to environmental perturbations in dry subhumid ecosystems.

PubMed

Hu, Hang-Wei; Macdonald, Catriona A; Trivedi, Pankaj; Holmes, Bronwyn; Bodrossy, Levente; He, Ji-Zheng; Singh, Brajesh K

2015-02-01

Terrestrial arid and semi-arid ecosystems (drylands) constitute about 41% of the Earth's land surface and are predicted to experience increasing fluctuations in water and nitrogen availability. Mounting evidence has confirmed the significant importance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in nitrification, plant nitrogen availability and atmospheric N2 O emissions, but their responses to environmental perturbations in drylands remain largely unknown. Here we evaluate how the factorial combinations of irrigation and fertilization in forests and land-use change from grassland to forest affects the dynamics of AOA and AOB following a 6-year dryland field study. Potential nitrification rates and AOA and AOB abundances were significantly higher in the irrigated plots, accompanied by considerable changes in community compositions, but their responses to fertilization alone were not significant. DNA-stable isotope probing results showed increased (13) CO2 incorporation into the amoA gene of AOA, but not of AOB, in plots receiving water addition, coupled with significantly higher net mineralization and nitrification rates. High-throughput microarray analysis revealed that active AOA assemblages belonging to Nitrosopumilus and Nitrosotalea were increasingly labelled by (13) CO2 following irrigation. However, no obvious effects of land-use changes on nitrification rates or metabolic activity of AOA and AOB could be observed under dry conditions. We provide evidence that water addition had more important roles than nitrogen fertilization in influencing the autotrophic nitrification in dryland ecosystems, and AOA are increasingly involved in ammonia oxidation when dry soils become wetted. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

The regulatory role of endogenous iron on greenhouse gas emissions under intensive nitrogen fertilization in subtropical soils of China.

PubMed

Han, Jiangpei; Shi, Liangsheng; Wang, Yakun; Chen, Zhuowei; Wu, Laosheng

2018-05-01

Anaerobic batch experiments were conducted to study the regulatory role of endogenous iron in greenhouse gas emissions under intensive nitrogen fertilization in subtropical soils of China. Fe 2+ , Fe 3+ , and NO 3 - -N dynamics and N 2 O, CH 4 , and CO 2 emissions, as well as the relationships between N fertilizer, endogenous iron, and greenhouse gas emissions were investigated. The emissions of N 2 O increased to different extents from all the test soils by N1 (260 mg N kg -1 ) application compared with N0. After 24 days of anaerobic incubation, the cumulative emissions of N 2 O from red soils in De'an (DR) were significantly higher than that from paddy soils in De'an (DP) and Qujialing (QP) under N1. However, N application enhanced CH 4 and CO 2 emissions from the red soils slightly but inhibited the emissions from paddy soils. The maximal CH 4 and CO 2 emission fluxes occurred in DP soil without N input. Pearson's correlation analysis showed that there were significant correlations (P < 0.01) between Fe 2+ and Fe 3+ , NO 3 - -N, (N 2 O + N 2 )-N concentrations in DP soil, implying that Fe 2+ oxidation was coupled with nitrate reduction accompanied by (N 2 O + N 2 )-N emissions and the endogenous iron played a regulatory role in greenhouse gas emissions mainly through the involvement in denitrification. The proportion of the electrons donated by Fe 2+ used for N 2 O production in denitrification in DP soil was approximately 37.53%. Moreover, positive correlations between Fe 2+ and CH 4 , CO 2 were found in both DR and QP soils, suggesting that endogenous iron might regulate the anaerobic decomposition of organic carbon to CH 4 and CO 2 in the two soils. Soil pH was also an important factor controlling greenhouse gas emissions by affecting endogenous iron availability and C and N transformation processes.

Respiratory carbon use and carbon storage in mid-rotation loblolly pine (Pinus taeda L.) plantations: the effect of site resources on the stand carbon balance

Treesearch

Chris A. Maier; Timothy J. Albaugh; H. Lee Allen; Phillip M. Dougherty

2004-01-01

We used estimates of autotrophic respiration (RA), net primary productivity (NPP) and soil CO2 evolution (Sff), to develop component carbon budgets for 12-year-old loblolly pine plantations during the fifth year of a fertilization and irrigation experiment. Annual carbon use in RA was 7.5, 9.0, 15.0, and 15.1 Mg C ha

Wireless Mid-Infrared Spectroscopy Sensor Network for Automatic Carbon Dioxide Fertilization in a Greenhouse Environment

PubMed Central

Wang, Jianing; Niu, Xintao; Zheng, Lingjiao; Zheng, Chuantao; Wang, Yiding

2016-01-01

In this paper, a wireless mid-infrared spectroscopy sensor network was designed and implemented for carbon dioxide fertilization in a greenhouse environment. A mid-infrared carbon dioxide (CO2) sensor based on non-dispersive infrared (NDIR) with the functionalities of wireless communication and anti-condensation prevention was realized as the sensor node. Smart transmission power regulation was applied in the wireless sensor network, according to the Received Signal Strength Indication (RSSI), to realize high communication stability and low-power consumption deployment. Besides real-time monitoring, this system also provides a CO2 control facility for manual and automatic control through a LabVIEW platform. According to simulations and field tests, the implemented sensor node has a satisfying anti-condensation ability and reliable measurement performance on CO2 concentrations ranging from 30 ppm to 5000 ppm. As an application, based on the Fuzzy proportional, integral, and derivative (PID) algorithm realized on a LabVIEW platform, the CO2 concentration was regulated to some desired concentrations, such as 800 ppm and 1200 ppm, in 30 min with a controlled fluctuation of <±35 ppm in an acre of greenhouse. PMID:27869725

Effects of different forms of plant-derived organic matter on nitrous oxide emissions.

PubMed

Qiu, Qingyan; Wu, Lanfang; Ouyang, Zhu; Li, Binbin; Xu, Yanyan

2016-07-13

To investigate the impact of different forms of plant-derived organic matter on nitrous oxide (N2O) emissions, an incubation experiment with the same rate of total nitrogen (N) application was carried out at 25 °C for 250 days. Soils were incorporated with maize-derived organic matter (i.e., maize residue-derived dissolved organic matter and maize residues with different C/N ratios) and an inorganic N fertilizer (urea). The pattern and magnitude of nitrous oxide (N2O) emissions were affected by the form of N applied. Single application of maize-derived organic matter resulted in a higher N2O emission than single application of the inorganic N fertilizer or combined application of the inorganic N fertilizer and maize-derived organic matter. The positive effect of maize residue-derived dissolved organic matter (DOM) addition on N2O emissions was relatively short-lived and mainly occurred at the early stage following DOM addition. In contrast, the positive effect induced by maize residue addition was more pronounced and lasted for a longer period. Single application of maize residues resulted in a substantial decrease in soil nitric nitrogen (NO3(-)-N), but it did not affect the production of N2O. No significant relationship between N2O emission and NO3(-)-N and ammonium nitrogen (NH4(+)-N) suggested that the availability of soil N was not limiting the production of N2O in our study. The key factors affecting soil N2O emission were the soil dissolved organic carbon (DOC) content and metabolism quotient (qCO2). Both of them could explain 87% of the variation in cumulative N2O emission. The C/N ratio of maize-derived organic matter was a poor predictor of N2O emission when the soil was not limited by easily available C and the available N content met the microbial N demands for nitrification and denitrification. The results suggested that the magnitude of N2O emission was determined by the impact of organic amendments on soil C availability and microbial activity rather than on soil N availability. In agricultural management practices, if the N inputs from organic and inorganic N fertilizers are equivalent, addition of organic N fertilizers that contain high amounts of available C will result in a higher N2O emission.

[Effects of interaction between vermicompost and probiotics on soil nronerty, yield and quality of tomato].

PubMed

Shen, Fei; Zhu, Tong-bin; Teng, Ming-jiao; Chen, Yue; Liu, Man-qiang; Hu, Feng; Li, Hui-xin

2016-02-01

In this study, we investigated the effects of two strains of probiotic bacteria (Bacillus megaterium BM and Bacillus amyloliquefaciens BA) combined with chemical fertilizers and vermicompost on the soil property, the yield and quality of tomato. The results showed that under the same nutrient level, vermicompost significantly increased the yield, soluble sugar and protein contents of fruit, the soil pH and available phosphorus when compared with chemical fertilizers. Vermicompost combined with probiotics not only increased the tomato yield, soluble sugar, protein and vitamin C contents, sugar/acid ratio of fruit, and reduced the organic acid and nitrate nitrogen contents of fruit, also increased the soil pH and nitrate nitrogen content, and reduced soil electric conductivity when compared with vermicompost treatment. This improved efficiency was better than that by chemical fertilizers combined with probiotics. For BA and BM applied with chemical fertilizers or vermicompost, both stains had no significant effect on tomato quality. When co-applied with vermicompost, BA and BM showed significant difference in tomato yield. High soil available phosphorus content was determined when BM was combined with chemical fertilizers, while high soil available potassium content was obtained when BA was combined with vermicompost. Our results suggested that probiotics and vermicompost could be used as alternatives of chemical fertilizers in tomato production and soil fertility improvement.

Effects of N Fertilizer Sources and Tillage Practices on NH3 Volatilization, Grain Yield, and N Use Efficiency of Rice Fields in Central China

PubMed Central

Liu, Tianqi; Huang, Jinfeng; Chai, Kaibin; Cao, Cougui; Li, Chengfang

2018-01-01

Tillage practices and nitrogen (N) sources are important factors affecting rice production. Few studies, however, have examined the interactions between tillage practices and N fertilizer sources on NH3 volatilization, nitrogen use efficiency (NUE), and rice grain yield. This study aimed to investigate the effects of N fertilizer sources (no N fertilizer, inorganic N fertilizer, organic N fertilizer alone, organic N fertilizer plus inorganic N fertilizer, and slow-release N fertilizer plus inorganic N fertilizer) and tillage practices (no-tillage [NT] and conventional intensive tillage [CT]) on NH3 flux, grain yield, and NUE in the rice field of central China. N sources significantly affected NH3 volatilization, as the cumulative volatilization from the treatments of inorganic N fertilizer, organic N fertilizer, organic N fertilizer plus inorganic N fertilizer, slow-release N fertilizer plus inorganic N fertilizer was 4.19, 2.13, 3.42, and 2.23 folds in 2013, and 2.49, 1.68, 2.08, and 1.85 folds in 2014 compared with that under no N fertilizer treatment, respectively. The organic N fertilizer treatment had the lowest grain yield and NUE among all N fertilizer treatments, while slow-release N fertilizer plus inorganic N fertilizer treatment led to relatively higher grain yield and the greatest N use efficiency. Moreover, NT only markedly increased NH3 volatilization from basal fertilizer by 10–14% in average compared with CT, but had no obvious effects on total volatilization during the whole seasons. Tillage practices had no significant effects on grain yield and NUE. Our study suggested that the combination of slow-release N fertilizer plus inorganic N fertilizer and NT might be a sustainable method for mitigating greenhouse gas and NH3 emissions and improving grain yield and NUE in paddy fields of central China. PMID:29623086

The sweet side of global change-dynamic responses of non-structural carbohydrates to drought, elevated CO2 and nitrogen fertilization in tree species.

PubMed

Li, Weibin; Hartmann, Henrik; Adams, Henry D; Zhang, Hongxia; Jin, Changjie; Zhao, Chuanyan; Guan, Dexin; Wang, Anzhi; Yuan, Fenghui; Wu, Jiabing

2018-06-11

Non-structural carbohydrates (NSC) play a central role in plant functioning as energy carriers and building blocks for primary and secondary metabolism. Many studies have investigated how environmental and anthropogenic changes, like increasingly frequent and severe drought episodes, elevated CO2 and atmospheric nitrogen (N) deposition, influence NSC concentrations in individual trees. However, this wealth of data has not been analyzed yet to identify general trends using a common statistical framework. A thorough understanding of tree responses to global change is required for making realistic predictions of vegetation dynamics. Here we compiled data from 57 experimental studies on 71 tree species and conducted a meta-analysis to evaluate general responses of stored soluble sugars, starch and total NSC (soluble sugars + starch) concentrations in different tree organs (foliage, above-ground wood and roots) to drought, elevated CO2 and N deposition. We found that drought significantly decreased total NSC in roots (-17.3%), but not in foliage and above-ground woody tissues (bole, branch, stem and/or twig). Elevated CO2 significantly increased total NSC in foliage (+26.2%) and roots (+12.8%), but not in above-ground wood. By contrast, total NSC significantly decreased in roots (-17.9%), increased in above-ground wood (+6.1%), but was unaffected in foliage from N fertilization. In addition, the response of NSC to three global change drivers was strongly affected by tree taxonomic type, leaf habit, tree age and treatment intensity. Our results pave the way for a better understanding of general tree function responses to drought, elevated CO2 and N fertilization. The existing data also reveal that more long-term studies on mature trees that allow testing interactions between these factors are urgently needed to provide a basis for forecasting tree responses to environmental change at the global scale.

Integrated effect of nutrients from a recirculation aquaponic system and foliar nutrition on the yield of tomatoes Solanum lycopersicum L. and Solanum pimpinellifolium.

PubMed

Gullian Klanian, Mariel; Delgadillo Diaz, Mariana; Aranda, Javier; Rosales Juárez, Carolina

2018-06-01

The objective of this study was to evaluate the potential of tomato plants to efficiently use the nitrogen (N) of a recirculation aquaponic system (RAS) and to evaluate the effects of foliar fertilization as a complement to the water nutrition on the growth of the two tomato cultivars. The significant effect of six macro- and seven micronutrients was evaluated on the plant growth and on the fruit yield. Two experiments were performed in a nutrient film aquaponic unit. The first experiment was designed to study the effects of foliar fertilization on the seedlings of two tomato cultivars Costoluto Genovese (CG) (Solanum lycopersicum L.) and Currant tomato (Ct) (Solanum pimpinellifolium) with 8% of weekly water exchange (WE8%-RAS). The foliar fertilizer was formulated with N restriction in the last 11 weeks (TF1). In the second experiment, two other foliar fertilization treatments (TF2 and TF3) were applied with a concentration of nutrients twice and triple that in TF1, but with a lower proportion of NPK ratio. These treatments were tested on the cultivar CG in a RAS with zero water exchange (WE0%-RAS). The data from the 1st experiment showed a positive effect of the foliar fertilization on the yield of both cultivars. The fertilization markedly influenced the dry matter weight of the CG; however, this effect was not observed in the Ct. The root length of both cultivars was positively influenced by the P content, whereas the plant height was affected by the excess of Co and S. According to the results from the 2nd experiment, the TF2 plants had the highest number of fruits with a high mean weight. The system was efficient in utilizing N from fish tank; the water K favored the yield of the CG fruit and the foliar K favored the growth of the TF2 plants. With a decrease in the foliar N, the CG plants were able to absorb 27.5% of the NO 3 - and 7.06% of total ammonia nitrogen from water. The absolute and relative growth rate of Nile tilapia was not affected by the rate of water exchange. Fulton's condition factor of the total length and weight curve indicated that fish from WE8%-RAS had wider bodies than the fish from WE0%-RAS at the same length range. Nitrate and P in the final effluent were lower than the maximum reference values allowed for the discharged water.

Shortening gametes co-incubation time improves live birth rate for couples with a history of fragmented embryos.

PubMed

Le Bras, Anne; Hesters, Laetitia; Gallot, Vanessa; Tallet, Cathie; Tachdjian, Gerard; Frydman, Nelly

2017-10-01

Short gamete co-incubation (SGCO) consists in decreasing the duration of contact between oocytes and sperm from the standard overnight insemination (SOI) toward 2 hours. However, the effectiveness of this technique to improve in vitro fertilization and embryo transfer (IVF-ET) outcomes remains controversial. Our study was designed to evaluate the efficiency of SGCO in a poor prognosis population with a history of fragmented embryos defined by the presence of at least 50% of the embryos with more than 25% of cytoplasmic fragments. From January 2010 to January 2014, 97 couples were included in a SGCO protocol. We separated women into 2 subgroups: younger and older than 35 years. Compared to SOI, after SGCO, 2-cell stage embryos were higher in all women (p<0.001) and less fragmented in women over 35 years (p<0.05). On day 2, top quality embryos obtained and transferred were higher with SCGO than with SOI, independently of the age of the women (p<0.001). Moreover, the number of embryos with less than 25% of fragmentation was higher after SGCO than SOI (p<0.001) whereas the number of multinucleated embryos was lower (p<0.001). We observed that after fresh ET, independently of the age of the women, the clinical pregnancy rate was 3 times higher after SGCO than after SOI. However, the live-birth rate was 4 times higher with SGCO than with SOI in women above 35 years but 3 times higher with SGCO than with SOI in women younger than 35 years. The present results indicate that for a particular indication, reducing the time of oocytes and sperm co-incubation may improve IVF-ET outcomes in terms of live-birth rate. AMH: anti mullerian hormone; COC: cumulus-oocytes complex; E2: estradiol; ET: embryo transfer; FET: frozen embryo transfer; FSH: follicle stimulating hormone; GnRH: gonadotrophin releasing hormone; hCG: human chorionic gonadotropin hormone; hMG: human menopausal gonadotropin hormone; IRB: institutional review board; IVF: in vitro fertilization; IVF-ET: in vitro fertilization and embryo transfer; MNB: multinucleated blastomere; mRNA: messanger ribonucleic acid; OC: oocyte retrieval; O2: oxygen; ROS: reactive oxygen species; SGCO: short gamete co-incubation; SOI: standard overnight insemination.

Testing amendments for remediation of military range contaminated soil.

PubMed

Siebielec, Grzegorz; Chaney, Rufus L

2012-10-15

Military range soils are often strongly contaminated with metals. Information on the effectiveness of remediation of these soils is scarce. We tested the effectiveness of compost and mineral treatments for remediation and revegetation of military range soil collected in Aberdeen, MD. The soil was barren due to zinc (Zn) phytotoxicity while lead (Pb) posed a substantial risk to soil biota, wildlife and humans through various pathways. Seven treatments were tested: untreated control, agricultural NPK fertilization, high phosphate fertilization plus agricultural rates of NK, CaCO(3), "Orgro" biosolid compost, "Orgro" + CaCO(3), "Orgro" + CaCO(3) + Mn sulfate. All compost treatments alleviated Zn phytotoxicity to tall fescue; however compost combined with liming reduced plant Zn content up to 158-162 mg kg(-1). Compost added with lime reduced Pb in-vitro bioaccessibility from 32.5 to 20.4% of total Pb and was the most effective among the tested treatments. The study revealed the effectiveness of biosolids compost and lime mixture in the rapid stabilization of metals and revegetation of military range contaminated soils. The persistence of the remediation needs to be, however, confirmed in the long-term field study. Copyright © 2012 Elsevier Ltd. All rights reserved.

Urea deep placement reduces yield-scaled greenhouse gas (CH4 and N2O) and NO emissions from a ground cover rice production system.

PubMed

Yao, Zhisheng; Zheng, Xunhua; Zhang, Yanan; Liu, Chunyan; Wang, Rui; Lin, Shan; Zuo, Qiang; Butterbach-Bahl, Klaus

2017-09-12

Ground cover rice production system (GCRPS), i.e., paddy soils being covered by thin plastic films with soil moisture being maintained nearly saturated status, is a promising technology as increased yields are achieved with less irrigation water. However, increased soil aeration and temperature under GCRPS may cause pollution swapping in greenhouse gas (GHG) from CH 4 to N 2 O emissions. A 2-year experiment was performed, taking traditional rice cultivation as a reference, to assess the impacts of N-fertilizer placement methods on CH 4 , N 2 O and NO emissions and rice yields under GCRPS. Averaging across all rice seasons and N-fertilizer treatments, the GHG emissions for GCRPS were 1973 kg CO 2 -eq ha -1 (or 256 kg CO 2 -eq Mg -1 ), which is significantly lower than that of traditional cultivation (4186 kg CO 2 -eq ha -1 or 646 kg CO 2 -eq Mg -1 ). Furthermore, if urea was placed at a 10-15 cm soil depth instead of broadcasting, the yield-scaled GHG emissions from GCRPS were further reduced from 377 to 222 kg CO 2 -eq Mg -1 , as N 2 O emissions greatly decreased while yields increased. Urea deep placement also reduced yield-scaled NO emissions by 54%. Therefore, GCRPS with urea deep placement is a climate- and environment-smart management, which allows for maximal rice yields at minimal GHG and NO emissions.

In vitro and in vivo effects of ulipristal acetate on fertilization and early embryo development in mice.

PubMed

Gómez-Elías, Matías D; Munuce, María J; Bahamondes, Luis; Cuasnicú, Patricia S; Cohen, Débora J

2016-01-01

Does ulipristal acetate (UPA), a selective progesterone receptor modulator used for emergency contraception (EC), interfere with fertilization or early embryo development in vitro and in vivo? At doses similar to those used for EC, UPA does not affect mouse gamete transport, fertilization or embryo development. UPA acts as an emergency contraceptive mainly by inhibiting or delaying ovulation. However, there is little information regarding its effects on post-ovulatory events preceding implantation. This was an in vitro and in vivo experimental study involving the use of mouse gametes and embryos from at least three animals in each set of experiments. For in vitro fertilization experiments, mouse epididymal spermatozoa capacitated in the presence of different concentrations of UPA (0-1000 ng/ml) were used to inseminate cumulus-intact or cumulus-free eggs in the presence or absence of UPA during gamete co-incubation, and the percentage of fertilized eggs was determined. For in vivo fertilization experiments, superovulated females caged with proven fertile males were injected with UPA (40 mg/kg) or vehicle just before or just after mating and the percentage of fertilized eggs recovered from the ampulla was determined. To investigate the effect of UPA on embryo development, zygotes were recovered from mated females, cultured in the presence of UPA (1000 ng/ml) for 4 days and the progression of embryo development was monitored daily. In vitro studies revealed that the presence of UPA during capacitation and/or gamete co-incubation does not affect fertilization. Whereas the in vivo administration of UPA at the same time as hCG injection produced a decrease in the number of eggs ovulated compared with controls (vehicle injected animals, P < 0.05), no effects on fertilization were observed when UPA was administered shortly before or after mating. No differences were observed in either the percentage of cleaved embryos or the cleavage speed when UPA was present during in vitro embryo culture. Considering the ethical and technical limitations inherent to the use of human gametes for fertilization studies, the mouse model was used as an approach for exploring the potential effects of UPA on in vivo sperm transport and fertilization. Nevertheless, the extrapolation of these results to humans requires further investigation. This study presents new evidence on the lack of effect of UPA on gamete interaction and embryo development, providing new insights into the mechanism of action of UPA as an emergency contraceptive method with potential clinical implications. These new findings could contribute to increase the acceptability and proper use of UPA as an emergency contraceptive method. This study was partially supported by a National Agency of Scientific and Technological Promotion (ANPCyT), Argentina grants PICT 2011-061 to D.J.C. and PICT 2011-2023 to P.S.C. None of the authors has any competing interests to declare. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Enhancing crop yield with the use of N-based fertilizers co-applied with plant hormones or growth regulators.

PubMed

Zaman, Mohammad; Kurepin, Leonid V; Catto, Warwick; Pharis, Richard P

2015-07-01

Crop yield, vegetative or reproductive, depends on access to an adequate supply of essential mineral nutrients. At the same time, a crop plant's growth and development, and thus yield, also depend on in situ production of plant hormones. Thus optimizing mineral nutrition and providing supplemental hormones are two mechanisms for gaining appreciable yield increases. Optimizing the mineral nutrient supply is a common and accepted agricultural practice, but the co-application of nitrogen-based fertilizers with plant hormones or plant growth regulators is relatively uncommon. Our review discusses possible uses of plant hormones (gibberellins, auxins, cytokinins, abscisic acid and ethylene) and specific growth regulators (glycine betaine and polyamines) to enhance and optimize crop yield when co-applied with nitrogen-based fertilizers. We conclude that use of growth-active gibberellins, together with a nitrogen-based fertilizer, can result in appreciable and significant additive increases in shoot dry biomass of crops, including forage crops growing under low-temperature conditions. There may also be a potential for use of an auxin or cytokinin, together with a nitrogen-based fertilizer, for obtaining additive increases in dry shoot biomass and/or reproductive yield. Further research, though, is needed to determine the potential of co-application of nitrogen-based fertilizers with abscisic acid, ethylene and other growth regulators. © 2014 Society of Chemical Industry.

Vascular parameters continue to decrease post-exposure with simultaneous, but not individual exposure to BPA and hypoxia in zebrafish larvae.

PubMed

Cypher, Alysha D; Fetterman, Bryce; Bagatto, Brian

2018-04-01

How fish respond to hypoxia, a common stressor, can be altered by simultaneous exposure to pollutants like bisphenol A (BPA), a plasticizer. BPA is cardiotoxic and interferes with the hypoxia inducible factor pathway (HIF-1α), therefore disrupting the hypoxic response. Co-exposure to hypoxia and BPA also causes severe bradycardia and reduced cardiac output in zebrafish larvae. The purpose of this work was to determine how the cardiovascular effects of co-exposure vary with BPA concentration and persist beyond exposure. Zebrafish embryos were exposed to 0, 0.01, 0.1, 1, and 100 μg/L of BPA during normoxia (>6.0 mg/L O 2 ) and hypoxia (2.0 ± 0.5 mg/L O 2 ) between 1 h post fertilization (hpf) and late hatching (72-96 hpf). Heart rate, cardiac output, and red blood cell (RBC) velocity were determined through video microscopy and digital motion analysis at late hatching and 10 days post fertilization (dpf), several days post exposure. In comparison to the hypoxic control, RBC velocity was 25% lower with 0.01 μg/L BPA and hypoxia at late hatching. At 10 dpf, the difference in RBC velocity between these treatments doubled, despite several days of recovery. This coincided with a 24% thinner outer diameter for caudal vein but no effect on cardiac or developmental parameters. Statistical interactions between BPA and oxygen concentration were found for arterial RBC velocity at both ages. Because the co-occurrence of both stressors is extremely common, it would be beneficial to understand how BPA and hypoxia interact to affect cardiovascular function during and after exposure. Copyright © 2018 Elsevier Inc. All rights reserved.

[Effects of different fertilization modes on vegetable growth, fertilizer nitrogen utilization, and nitrogen loss from vegetable field].

PubMed

Huang, Dong-feng; Wang, Guo; Li, Wei-hua; Qiu, Xiao-xuan

2009-03-01

A field experiment with Chinese cabbage, water spinach, and three-colored amaranth cropped three times in one year was conducted to study the effects of seven fertilization modes, i.e., none fertilization, basal application of chemical fertilizers, 1/2 basal application and 1/2 top-dressing of chemical fertilizers, basal application of chemical fertilizers and dicyandiamide, 1/2 basal application and 1/2 top-dressing of chemical fertilizers and dicyandiamide, 1/2 basal application and 1/2 top-dressing of chemical fertilizers and organic manure, and basal application of organic manure, on the plant height, yield, nitrogen accumulation, and fertilizer nitrogen utilization of the vegetables, and the loss of NO3- -N and NH4+ -N from vegetable field under natural rainfall condition. The results showed that comparing with none fertilization, the fertilization modes '1/2 basal application and 1/2 top-dressing of chemical fertilizers and organic manure' and 'basal application of chemical fertilizers and dicyandiamide' improved the agronomic properties of test vegetables, increased their yields by 103%-219% and 93%-226%, and nitrogen accumulation by 153% -216% and 231%-320%, respectively, and enhanced fertilizer nitrogen utilization rate. They also decreased the surface runoff loss of NO3- -N and NH4+ -N by 48.1% and 46.5%, respectively, compared with the mode 'basal application of chemical fertilizers', and hence, reduced the risk of agricultural non-point pollution. Therefore, these two fertilization modes could be popularized in vegetable production.

Growth response of Douglas-fir seedlings to nitrogen fertilization: importance of Rubisco activation state and respiration rates.

PubMed

Manter, Daniel K; Kavanagh, Kathleen L; Rose, Cathy L

2005-08-01

High foliar nitrogen concentration ([N]) is associated with high rates of photosynthesis and thus high tree productivity; however, at excessive [N], tree productivity is reduced. Reports of excessive [N] in the Douglas-fir forests of the Oregon Coast Range prompted this investigation of growth and needle physiological responses to increasing foliar N concentrations in 1-year-old Douglas-fir seedlings. After 1 year of N fertilization, total seedling biomass increased with each successive increase in N fertilizer concentration, except in the highest N fertilization treatment. Of the many physiological responses that were analyzed, only photosynthetic capacity (i.e., Vcmax), respiration rates and leaf specific conductance (KL) differed significantly between N treatments. Photosynthetic capacity showed a curvilinear relationship with foliar [N], reaching an apparent maximum rate when needle N concentrations exceeded about 12 mg g(-1). In vitro measurements of ribulose-1,5-bisphosphate carboxylase (Rubisco) activity suggested that photosynthetic capacity was best related to activated, not total, Rubisco content. Rubisco activation state declined as foliar [N] increased, and based on its significant correlation (r2= 0.63) with foliar Mn:Mg ratios, it may be related to Mn inactivation of Rubisco. Respiration rates increased linearly as foliar N concentration increased (r2= 0.84). The value of K(L) also increased as foliar [N] increased, reaching a maximum when foliar [N] exceeded about 10 mg g(-1). Changes in K(L) were unrelated to changes in leaf area or sapwood area because leaf area to sapwood area ratios remained constant. Cumulative effects of the observed physiological responses to N fertilization were analyzed by modeling annual net CO2 assimilation (Anet) based on treatment specific values of Vcmax, dark respiration (Rdark) and KL. Estimates of Anet were highly correlated with measured total seedling biomass (r2= 0.992), suggesting that long-term, cumulative effects of maximum Rubisco carboxylation, Rdark and KL responses to N fertilization may limit seedling production when foliar N exceeds about 13 mg g(-1) or is reduced to less than about 11 mg g(-1).

Effects of seawater acidification on the early development of sea urchin Glyptocidaris crenularis

NASA Astrophysics Data System (ADS)

Zhan, Yaoyao; Hu, Wanbin; Duan, Lizhu; Liu, Minbo; Zhang, Weijie; Chang, Yaqing; Li, Cong

2017-10-01

In this study, we evaluated the effects of CO2-induced seawater acidification on fertilization, embryogenesis and early larval development in the sea urchin Glyptocidaris crenularis, that inhabits subtidal coastal areas in northern China. The range in seawater pH used in experiments was based on the projections of the Intergovernmental Panel on Climate Change (IPCC), to the year 2100. A natural seawater treatment (pHnbs=7.98±0.03) and three laboratory-controlled acidified treatments (OA1, ΔpHnbs=-0.3 units; OA2, ΔpHnbs=-0.4 units; OA3, ΔpHnbs=-0.5 units) were used in experiments. Results show that: (1) there was a negative effect of seawater acidification on fertilization and on the percentage of abnormal fertilized eggs; (2) the size of early cleavage stage embryos decreased in a dose-dependent manner with decreasing pH; (3) both the hatching rate of blastulae and the survival rate of four-armed pluteus larvae decreased as pH declined; (4) larval abnormalities including asymmetrical development, changes in the length of skeletal elements, and corroded spicules were observed in all seawater acidified-treatments compared with the control. These data indicate that seawater acidification has a negative impact on the early development of G. crenularis, and supports the hypothesis that the response of echinoderms to ocean acidification (OA) varies among species. Further research is required to clarify the specific cellular mechanisms involved.

Elevated CO2 enhances biological contributions to elevation change in coastal wetlands by offsetting stressors associated with sea-level rise

USGS Publications Warehouse

Cherry, J.A.; McKee, K.L.; Grace, J.B.

2009-01-01

1. Sea-level rise, one indirect consequence of increasing atmospheric CO2, poses a major challenge to long-term stability of coastal wetlands. An important question is whether direct effects of elevated CO 2 on the capacity of marsh plants to accrete organic material and to maintain surface elevations outweigh indirect negative effects of stressors associated with sea-level rise (salinity and flooding). 2. In this study, we used a mesocosm approach to examine potential direct and indirect effects of atmospheric CO2 concentration, salinity and flooding on elevation change in a brackish marsh community dominated by a C3 species, Schoenoplectus americanus, and a C4 grass, Spartina patens. This experimental design permitted identification of mechanisms and their role in controlling elevation change, and the development of models that can be tested in the field. 3. To test hypotheses related to CO2 and sea-level rise, we used conventional anova procedures in conjunction with structural equation modelling (SEM). SEM explained 78% of the variability in elevation change and showed the direct, positive effect of S. americanus production on elevation. The SEM indicated that C3 plant response was influenced by interactive effects between CO2 and salinity on plant growth, not a direct CO2 fertilization effect. Elevated CO2 ameliorated negative effects of salinity on S. americanus and enhanced biomass contribution to elevation. 4. The positive relationship between S. americanus production and elevation change can be explained by shoot-base expansion under elevated CO 2 conditions, which led to vertical soil displacement. While the response of this species may differ under other environmental conditions, shoot-base expansion and the general contribution of C3 plant production to elevation change may be an important mechanism contributing to soil expansion and elevation gain in other coastal wetlands. 5. Synthesis. Our results revealed previously unrecognized interactions and mechanisms contributing to marsh elevation change, including amelioration of salt stress by elevated CO2 and the importance of plant production and shoot-base expansion for elevation gain. Identification of biological processes contributing to elevation change is an important first step in developing comprehensive models that permit more accurate predictions of whether coastal marshes will persist with continued sea-level rise or become submerged. ?? 2008 The Authors.

Evaluation of terrestrial carbon cycle models with atmospheric CO2 measurements: Results from transient simulations considering increasing CO2, climate, and land-use effects

USGS Publications Warehouse

Dargaville, R.J.; Heimann, Martin; McGuire, A.D.; Prentice, I.C.; Kicklighter, D.W.; Joos, F.; Clein, Joy S.; Esser, G.; Foley, J.; Kaplan, J.; Meier, R.A.; Melillo, J.M.; Moore, B.; Ramankutty, N.; Reichenau, T.; Schloss, A.; Sitch, S.; Tian, H.; Williams, L.J.; Wittenberg, U.

2002-01-01

An atmospheric transport model and observations of atmospheric CO2 are used to evaluate the performance of four Terrestrial Carbon Models (TCMs) in simulating the seasonal dynamics and interannual variability of atmospheric CO2 between 1980 and 1991. The TCMs were forced with time varying atmospheric CO2 concentrations, climate, and land use to simulate the net exchange of carbon between the terrestrial biosphere and the atmosphere. The monthly surface CO2 fluxes from the TCMs were used to drive the Model of Atmospheric Transport and Chemistry and the simulated seasonal cycles and concentration anomalies are compared with observations from several stations in the CMDL network. The TCMs underestimate the amplitude of the seasonal cycle and tend to simulate too early an uptake of CO2 during the spring by approximately one to two months. The model fluxes show an increase in amplitude as a result of land-use change, but that pattern is not so evident in the simulated atmospheric amplitudes, and the different models suggest different causes for the amplitude increase (i.e., CO2 fertilization, climate variability or land use change). The comparison of the modeled concentration anomalies with the observed anomalies indicates that either the TCMs underestimate interannual variability in the exchange of CO2 between the terrestrial biosphere and the atmosphere, or that either the variability in the ocean fluxes or the atmospheric transport may be key factors in the atmospheric interannual variability.

Frozen Cropland Soil in Northeast China as Source of N2O and CO2 Emissions

PubMed Central

Qiao, Yunfa; Han, Xiaozeng; Brancher Franco, Roberta

2014-01-01

Agricultural soils are important sources of atmospheric N2O and CO2. However, in boreal agro-ecosystems the contribution of the winter season to annual emissions of these gases has rarely been determined. In this study, soil N2O and CO2 fluxes were measured for 6 years in a corn-soybean-wheat rotation in northeast China to quantify the contribution of wintertime N2O and CO2 fluxes to annual emissions. The treatments were chemical fertilizer (NPK), chemical fertilizer plus composted pig manure (NPKOM), and control (Cont.). Mean soil N2O fluxes among all three treatments in the winter (November–March), when soil temperatures are below −7°C for extended periods, were 0.89–3.01 µg N m−2 h−1, and in between the growing season and winter (October and April), when freeze-thaw events occur, 1.73–5.48 µg N m−2 h−1. The cumulative N2O emissions were on average 0.27–1.39, 0.03–0.08 and 0.03–0.11 kg N2O–N ha−1 during the growing season, October and April, and winter, respectively. The average contributions of winter N2O efflux to annual emissions were 6.3–12.1%. In all three seasons, the highest N2O emissions occurred in NPKOM, while NPK and Cont. emissions were similar. Cumulative CO2 emissions were 2.73–4.94, 0.13–0.20 and 0.07–0.11 Mg CO2-C ha−1 during growing season, October and April, and winter, respectively. The contribution of winter CO2 to total annual emissions was 2.0–2.4%. Our results indicate that in boreal agricultural systems in northeast China, CO2 and N2O emissions continue throughout the winter. PMID:25536036

Potential role of compost and green manure amendment to mitigate soil GHGs emissions in Mediterranean drip irrigated maize production systems.

PubMed

Forte, Annachiara; Fagnano, Massimo; Fierro, Angelo

2017-05-01

Organic fertilization can preserve soil organic matter (SOM) and is foreseen as an effective strategy to reduce green house gases (GHGs) emissions in agriculture. However, its effectiveness needs to be clarified under specific climate, crop management and soil characteristics. A field experiment was carried out in a Mediterranean drip irrigated maize system to assess the pattern of soil CO 2 and N 2 O fluxes in response to the replacement of a typical bare fallow-maize cycle under urea fertilization (130 kg N ha -1 y -1 ) (CONV) with: (i) bare fallow-maize cycles under two doses of compost (COM1 and COM2, 130 and 260 kg N ha -1 y -1 , respectively) and (ii) a vetch-maize cycle, with vetch incorporation as green manure (130 kg N ha -1 y -1 ) (GMAN). Along the maize period (MP), reduced daily N 2 O emissions were detected in organic treated soils compared to CONV, mainly in the first stages of the cultivation, thanks to the slow release of available nitrogen from the organic substrates. Cumulative N 2 O fluxes (kg N 2 O-N ha -1 ) in MP scored to 0.24, 0.14, 0.12 and 0.085 for CONV, COM1, COM2 and GMAN, respectively, with significantly lower emissions in GMAN respect to CONV. CO 2 fluxes partially reflected the ranking observed for maize yields, with cumulated values (Mg CO 2 -C ha -1 ) of 2.2, 1.5, 2.1, 2.1 for CONV, COM1, COM2 and GMAN, respectively, and significantly lower in COM1 respect to the other treatments. During the fallow period (FP), compared to CONV (0.77 Mg CO 2 -C ha -1 and 0.25 kg N 2 O-N ha -1 ), enhanced GHG fluxes were detected in COM treatments (about 0.90 Mg CO 2 -C ha -1 and 0.37 kg N 2 O-N ha -1 , as averaged values from COM1 and COM2), likely driven by the slow prolonged mineralization of the added organic matter. GMAN showed comparable CO 2 (0.82 Mg CO 2 -C ha -1 ) and N 2 O emissions (0.30 kg N 2 O-N ha -1 ), in consequence of restrained post-harvest residual N coupled with the counteracting effect of vetch uptake. Respect to the total yearly GHG emissions in CONV (about 194 kg CO 2 eq ha -1 y -1 ), the overall results showed commensurate slightly higher GWP in COM treatments (+11% as averaged value from COM1 and COM2). The yield-scaled global warming potential (GWP) resulted 60% higher and nearly doubled for COM2 and COM1 respectively, according to the lower COM yields, markedly dampening at halved compost dose. GMAN appeared the best performing organic treatment, with lower GWP (-27%) and competitive yields respect to CONV. All treatments showed N 2 O emission factors consistently lower compared with the default IPCC 1% value. Copyright © 2017 Elsevier Ltd. All rights reserved.

Increased CO2 stimulates reproduction in a coral reef fish.

PubMed

Miller, Gabrielle M; Watson, Sue-Ann; McCormick, Mark I; Munday, Philip L

2013-10-01

Ocean acidification is predicted to negatively impact the reproduction of many marine species, either by reducing fertilization success or diverting energy from reproductive effort. While recent studies have demonstrated how ocean acidification will affect larval and juvenile fishes, little is known about how increasing partial pressure of carbon dioxide (pCO(2)) and decreasing pH might affect reproduction in adult fishes. We investigated the effects of near-future levels of pCO(2) on the reproductive performance of the cinnamon anemonefish, Amphiprion melanopus, from the Great Barrier Reef, Australia. Breeding pairs were held under three CO(2) treatments [Current-day Control (430 μatm), Moderate (584 μatm) and High (1032 μatm)] for a 9-month period that included the summer breeding season. Unexpectedly, increased CO(2) dramatically stimulated breeding activity in this species of fish. Over twice as many pairs bred in the Moderate (67% of pairs) and High (55%) compared to the Control (27%) CO(2) treatment. Pairs in the High CO(2) group produced double the number of clutches per pair and 67% more eggs per clutch compared to the Moderate and Control groups. As a result, reproductive output in the High group was 82% higher than that in the Control group and 50% higher than that in the Moderate group. Despite the increase in reproductive activity, there was no difference in adult body condition among the three treatment groups. There was no significant difference in hatchling length between the treatment groups, but larvae from the High CO(2) group had smaller yolks than Controls. This study provides the first evidence of the potential effects of ocean acidification on key reproductive attributes of marine fishes and, contrary to expectations, demonstrates an initially stimulatory (hormetic) effect in response to increased pCO(2). However, any long-term consequences of increased reproductive effort on individuals or populations remain to be determined. © 2013 John Wiley & Sons Ltd.

Does encapsulation protect embryos from the effects of ocean acidification? The example of Crepidula fornicata.

PubMed

Noisette, Fanny; Comtet, Thierry; Legrand, Erwann; Bordeyne, François; Davoult, Dominique; Martin, Sophie

2014-01-01

Early life history stages of marine organisms are generally thought to be more sensitive to environmental stress than adults. Although most marine invertebrates are broadcast spawners, some species are brooders and/or protect their embryos in egg or capsules. Brooding and encapsulation strategies are typically assumed to confer greater safety and protection to embryos, although little is known about the physico-chemical conditions within egg capsules. In the context of ocean acidification, the protective role of encapsulation remains to be investigated. To address this issue, we conducted experiments on the gastropod Crepidula fornicata. This species broods its embryos within capsules located under the female and veliger larvae are released directly into the water column. C. fornicata adults were reared at the current level of CO2 partial pressure (pCO2) (390 μatm) and at elevated levels (750 and 1400 μatm) before and after fertilization and until larval release, such that larval development occurred entirely at a given pCO2. The pCO2 effects on shell morphology, the frequency of abnormalities and mineralization level were investigated on released larvae. Shell length decreased by 6% and shell surface area by 11% at elevated pCO2 (1400 μatm). The percentage of abnormalities was 1.5- to 4-fold higher at 750 μatm and 1400 μatm pCO2, respectively, than at 390 μatm. The intensity of birefringence, used as a proxy for the mineralization level of the larval shell, also decreased with increasing pCO2. These negative results are likely explained by increased intracapsular acidosis due to elevated pCO2 in extracapsular seawater. The encapsulation of C. fornicata embryos did not protect them against the deleterious effects of a predicted pCO2 increase. Nevertheless, C. fornicata larvae seemed less affected than other mollusk species. Further studies are needed to identify the critical points of the life cycle in this species in light of future ocean acidification.

Optimizing Available Phosphorus in Calcareous Soils Fertilized with Diammonium Phosphate and Phosphoric Acid Using Freundlich Adsorption Isotherm

PubMed Central

Akhtar, Muhammad

2013-01-01

In calcareous soils, phosphorus (P) retention and immobilization take place due to precipitation and adsorption. Since soil pH is considered a major soil variable affecting the P sorption, an acidic P fertilizer could result in low P adsorption compared to alkaline one. Therefore, P adsorption from DAP and phosphoric acid (PA) required to produce desired soil solution P concentration was estimated using Freundlich sorption isotherms. Two soils from Faisalabad and T. T. Singh districts were spiked with 0, 10, and 20 % CaCO3 for 15 days. Freundlich adsorption isotherms (P = aC b/a) were constructed, and theoretical doses of PA and DAP to develop a desired soil solution P level (i.e., 0.20 mg L−1) were calculated. It was observed that P adsorption in soil increased with CaCO3. Moreover, at all the levels of CaCO3, P adsorption from PA was lower compared to that from DAP in both the soils. Consequently, lesser quantity of PA was required to produce desired solution P, 0.2 mg L−1, compared to DAP. However, extrapolating the developed relationship between soil CaCO3 contents and quantity of fertilizer to other similar textured soils needs confirmation. PMID:24307878

Enhanced terrestrial carbon uptake: global drivers and implications for the growth rate of atmospheric CO2.

NASA Astrophysics Data System (ADS)

Keenan, Trevor F.; Prentice, Colin; Canadell, Josep; Williams, Christopher; Han, Wang; Riley, William; Zhu, Qing; Koven, Charlie; Chambers, Jeff

2017-04-01

In this presentation we will focus on using decadal changes in the global carbon cycle to better understand how ecosystems respond to changes in CO2 concentration, temperature, and water and nutrient availability. Using global carbon budget estimates, ground, atmospheric and satellite observations, and multiple process-based global vegetation models, we examine the causes and consequences of the long-term changes in the terrestrial carbon sink. We show that over the past century the sink has been greatly enhanced, largely due to the effect of elevated CO2 on photosynthesis dominating over warming induced increases in respiration. We also examine the relative roles of greening, water and nutrients, along with individual events such as El Nino. We show that a slowdown in the rate of warming over land since the start of the 21st century likely led to a large increase in the sink, and that this increase was sufficient to lead to a pause in the growth rate of atmospheric CO2. We also show that the recent El Nino resulted in the highest growth rate of atmospheric CO2 ever recorded. Our results provide evidence of the relative roles of CO2 fertilization and warming induced respiration in the global carbon cycle, along with an examination of the impact of climate extremes.

Elevated CO2: Impact on diurnal patterns of photosynthesis in natural microbial ecosystems

NASA Technical Reports Server (NTRS)

Rothschild, L. J.

1994-01-01

Algae, including blue-green algae (cyanobacteria), are the major source of fixed carbon in many aquatic ecosystems. Previous work has shown that photosynthetic carbon fixation is often enhanced in the presence of additional carbon dioxide (CO2). This study was undertaken to determine if this CO2 fertilization effect extended to microbial mats, and, if so, at what times during the day might the addition of CO2 affect carbon fixation. Four microbial mats from diverse environments were selected, including mats from a hypersaline pond (area 5, Exportadora de Sal, Mexico), the marine intertidal (Lyngbya, Laguna Ojo de Liebre, Mexico), an acidic hotspring (Cyanidium, Nymph Creek, Yellowstone National Park), and an acidic stream at ambient temperature (Zygogonium, Yellowstone National Park). Carbon fixation in the absence of additional CO2 essentially followed the rising and falling sunlight levels, except that during the middle of the day there was a short dip in carbon fixation rates. The addition of CO2 profoundly enhanced carbon fixation rates during the daylight hours, including during the midday dip. Therefore, it is unlikely that the midday dip was due to photoinhibition. Surprisingly, enhancement of carbon fixation was often greatest in the early morning or late afternoon, times when carbon fixation would be most likely to be light limited.

Using biochar in animal farming to recycle nutrients and reduce greenhouse gas emissions

NASA Astrophysics Data System (ADS)

Schmidt, Hans-Peter; Wilson, Kelpie; Kammann, Claudia

2017-04-01

Charcoal has been used to treat digestive disorder in animals since several thousand years. But only since about 2010 biochar has increasingly been used as regular feed additive in animal farming usually mixed with standard feed at approximately 1% of the daily feed intake. The use of biochar as feed additive has the potential to improve animal health, feed efficiency and the animal-stable environment; to reduce nutrient losses and GHG emissions; and to increase soil organic mater and thus soil fertility. The evaluation of more than 150 scientific papers on feeding (activated) biochar showed in most of the studies and for all investigated livestock species positive effects on parameters like toxin adsorption, digestion, blood values, feed use efficiency and livestock weight gain, meat quality and GHG emissions. The facilitation of direct electron transfers between different species of bacteria or microbial consortia via the biochar mediator in the animal digestion tract is hypothesized to be the main reason for a more energy efficient digestion and thus higher feed efficiency, for its selective probiotic effect, for reduced N-losses and eventually for less GHG emissions. While chicken, pigs, fish and other omnivore animals provoke GHG-emissions (mainly NH3, CH4, N2O) when their liquid and solid excretions decompose anaerobically, ruminants cause direct methane emissions through flatulence and burps (eructation). Preliminary studies demonstrated that feeding high temperature biochars might reduce ruminant CH4 emissions though more systematic research is needed. It is likely that microbial decomposition of manure containing digested biochar produces less ammonia, less methane and thus retain more nitrogen, as seen when manure was composted with and without biochar or when biochar is used as bedding or manure treatment additive. Laboratory adsorption trials estimated that using biochar for liquid manure treatment could safe 57,000 t NH4 and 4,600 t P2O5 fertilizer per year in California alone. It was further shown that feeding 0.3 to 1% biochar could replace antibiotic treatment in chicken and ducks, respectively. Feeding biochar could thus have an indirect effect on GHG emissions when it is able to replace regular antibiotic "feeding" that produces high indirect GHG emissions after soil application of antibiotic contaminated manure. Moreover, it was demonstrated that feeding biochar to grazing cows had positive secondary effects on soil fertility and fertilizer efficiency reducing mineral N-fertilizing requirements which could be another indirect biochar GHG mitigation effect. Considering an average C-content of fed biochar of 80% and produced at recommended temperatures above 500°C resulting in H/Corg ratios below 0.4, at least 56% of the dry weight of the fed and manure-applied biochar would persist as stable carbon in soil for at least 100 years. If the global livestock would receive 1% of their feed in form of such a biochar, a total of about 400 Mt of CO2eq or 1.2 % of the global CO2 emissions could be compensated. The apparent potential for improving animal health and nutrient efficiency, for reducing enteric methane emissions as well as GHG emissions from manure management and for sequestering carbon with soil fertility improvements makes it compelling to increase the scientific effort to investigate, measure and optimize the GHG reduction potential of biochar use in animal farming systems. The main results from literature and own experiments will be presented to illustrate and calculate this potential.

Interaction of ice storms and management practices on current carbon sequestration in forests with potential mitigation under future CO2 atmosphere

Treesearch

Heather R. McCarthy; Ram Oren; Hyun-Seok Kim; Kurt H. Johnsen; Chris Maier; Seth G. Pritchard; Michael A. Davis

2006-01-01

Ice storms are disturbance events with potential impacts on carbon sequestration. Common forest management practices, such as fertilization and thinning, can change wood and stand properties and thus may change vulnerability to ice storm damage. At the same time, increasing atmospheric CO2 levels may also influence ice storm vulnerability. Here...

Biogeologic Carbon Sequestration - a Cost-Effective Proposal

NASA Astrophysics Data System (ADS)

Shaw, G. H.; Kuhns, R.

2009-05-01

Carbon sequestration has been proposed as a strategy for reducing the impact of carbon dioxide emissions from burning of fossil fuels. There are two main routes: 1) capture CO2 emissions from power plants or other large point sources followed by some form of "burial/sequestration", and 2) extraction of CO2 from the ambient atmosphere (involving substantial concentration relative to atmospheric levels) also followed by burial/sequestration. In either case the goal is to achieve significant long-term isolation of CO2 at an economically sustainable price, perhaps measured by some "market price" for CO2, such as the European carbon futures market, where the price is now (2/3/09) about 14-15/tonne of CO2. The second approach, removal of CO2 from the atmosphere, has the potential benefit of reversing the previous buildup of atmospheric CO2, and perhaps even providing a means to "adjust" terrestrial climate by regulating atmospheric CO2 concentrations. For the present, ideas of planetary "geo-engineering" are not as popular as reducing the impact of continued CO2 emissions. In fact, the energy and capital costs of extraction from a dilute atmosphere appear to make this approach uneconomical. Proposals to fertilize the open ocean suffer from concerns about long term ecosystem effects, to say nothing of a lack of verifiability. There is, however, an approach using biological systems that can not only extract significant amounts of CO2, but can do so cost-effectively. Lakes are known in which primary productivity approaches or exceeds 1gm C/cm2-yr. This equates to removal of 35,000 tonnes of CO2 per km2 per year, with a "market value" of about 500,000/yr. Such productivity only occurs under highly eutrophic conditions, and presumably requires significant nutrient additions. As such it would be unthinkable to pursue this technique on a large scale in extant lakes. If, however, it is possible to produce one or more large artificial lakes under acceptable conditions it is conceivable that this approach to carbon sequestration could prove invaluable in both the near and long term.

Elevated CO2 induces substantial and persistent declines in forage quality irrespective of warming in mixedgrass prairie.

PubMed

Augustine, David J; Blumenthal, Dana M; Springer, Tim L; LeCain, Daniel R; Gunter, Stacey A; Derner, Justin D

2018-04-01

Increasing atmospheric [CO 2 ] and temperature are expected to affect the productivity, species composition, biogeochemistry, and therefore the quantity and quality of forage available to herbivores in rangeland ecosystems. Both elevated CO 2 (eCO 2 ) and warming affect plant tissue chemistry through multiple direct and indirect pathways, such that the cumulative outcomes of these effects are difficult to predict. Here, we report on a 7-yr study examining effects of CO 2 enrichment (to 600 ppm) and infrared warming (+1.5°C day/3°C night) under realistic field conditions on forage quality and quantity in a semiarid, mixedgrass prairie. For the three dominant forage grasses, warming effects on in vitro dry matter digestibility (IVDMD) and tissue [N] were detected only in certain years, varied from negative to positive, and were relatively minor. In contrast, eCO 2 substantially reduced IVDMD (two most abundant grasses) and [N] (all three dominant grass species) in most years, except the two wettest years. Furthermore, eCO 2 reduced IVDMD and [N] independent of warming effects. Reduced IVDMD with eCO 2 was related both to reduced [N] and increased acid detergent fiber (ADF) content of grass tissues. For the six most abundant forage species (representing 96% of total forage production), combined warming and eCO 2 increased forage production by 38% and reduced forage [N] by 13% relative to ambient climate. Although the absolute magnitude of the decline in IVDMD and [N] due to combined warming and eCO 2 may seem small (e.g., from 63.3 to 61.1% IVDMD and 1.25 to 1.04% [N] for Pascopyrum smithii), such shifts could have substantial consequences for the rate at which ruminants gain weight during the primary growing season in the largest remaining rangeland ecosystem in North America. With forage production increases, declining forage quality could potentially be mitigated by adaptively increasing stocking rates, and through management such as prescribed burning, fertilization at low rates, and legume interseeding to enhance forage quality. © 2018 by the Ecological Society of America.

Iron Fertilization of the Southern Ocean: Regional Simulation and Analysis of C-Sequestration in the Ross Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kevin Arrigo

2012-03-13

A modified version of the dynamic 3-dimensional mesoscale Coupled Ice, Atmosphere, and Ocean model (CIAO) of the Ross Sea ecosystem has been used to simulate the impact of environmental perturbations upon primary production and biogenic CO2 uptake. The Ross Sea supports two taxonomically, and spatially distinct phytoplankton populations; the haptophyte Phaeocystis antarctica and diatoms. Nutrient utilization ratios predict that P. antarctica and diatoms will be driven to nitrate and phosphate limitation, respectively. Model and field data have confirmed that the Ross Sea is iron limited with only two-thirds of the macronutrients consumed by the phytoplankton by the end of themore » growing season. In this study, the CIAO model was improved to simulate a third macronutrient (phosphate), dissolved organic carbon, air-sea gas exchange, and the carbonate system. This enabled us to effectively model pCO2 and subsequently oceanic CO2 uptake via gas exchange, allowing investigations into the affect of alleviating iron limitation on both pCO2 and nutrient drawdown.« less

CO2 and CH4 exchanges between land ecosystems and the atmosphere in northern high latitudes over the 21st century

USGS Publications Warehouse

Zhuang, Q.; Melillo, J.M.; Sarofim, M.C.; Kicklighter, D.W.; McGuire, A.D.; Felzer, B.S.; Sokolov, A.; Prinn, R.G.; Steudler, P.A.; Hu, S.

2006-01-01

Terrestrial ecosystems of the northern high latitudes (above 50??N) exchange large amounts of CO2 and CH4 with the atmosphere each year. Here we use a process-based model to estimate the budget of CO 2 and CH4 of the region for current climate conditions and for future scenarios by considering effects of permafrost dynamics, CO 2 fertilization of photosynthesis and fire. We find that currently the region is a net source of carbon to the atmosphere at 276 Tg C yr -1. We project that throughout the 21st century, the region will most likely continue as a net source of carbon and the source will increase by up to 473 Tg C yr-1 by the end of the century compared to the current emissions. However our coupled carbon and climate model simulations show that these emissions will exert relatively small radiative forcing on global climate system compared to large amounts of anthropogenic emissions. Copyright 2006 by the American Geophysical Union.

Source identification and exchangeability of heavy metals accumulated in vegetable soils in the coastal plain of eastern Zhejiang province, China.

PubMed

Qiutong, Xu; Mingkui, Zhang

2017-08-01

Vegetable production in China is suffering increasingly heavy metal damages from various pollution sources including agricultural, industrial and other activities. It is of practical significance to understand the effects of human activities on the accumulation and exchangeability of soil heavy metals in vegetable fields. In this study, seventy-two arable layer samples of vegetable soils were collected from the Shaoxing coastal plain, a representative region of the coastal plain of eastern Zhejiang province, China for characterizing the effects of fertilization methods on accumulation and exchangeable heavy metals in soils (Exchangeable heavy metals in the soil samples were extracted by 0.01molL -1 CaCl 2 ). The different origins of heavy metals in the vegetable soils were investigated by multivariate statistical techniques, including principal component analysis (PCA) and cluster analysis (CA). Marked increases were noted for soil heavy metals due to long-term manure or chemical fertilizer application. Three significant components were extracted by PCA, explaining 78.86% of total variance. Mn, Co, Ni, Fe, and Al were associated in lithogenic components, while an anthropogenic origin was identified for Cu, Cr, Pb, Zn, Cd, Hg. However, As level was due to the geochemical background and was not linked to soil management. The results obtained by cluster analysis elucidated individual relationships between metals and agreed with PCA. Cu, Cr, Pb, and Zn in the soils that were mainly associated with the application of chemical fertilizers, organic manures or other activities regarding soil management. Although the origin of Cd, Hg, and As was also attributed to soil management, other sources like vehicle exhaust or aerial depositions were not discarded as possible contributors. Soil amended with organic fertilizer contained more Cu, Pb, Zn and Cr; whereas the soil amended with chemical fertilizer had more Cd. Application of fertilizers also had significant effect on the concentrations of exchangeable heavy metals. Higher mean concentrations of exchangeable Cd and Pb were found in the soils amended with chemical fertilizers, while those of exchangeable Cu and Zn were found in the soils amended with organic fertilizers. Copyright © 2017 Elsevier Inc. All rights reserved.

The Potential Impacts of Nutrient and CO2 Variations on Ecosystem Oxidative Ratio

NASA Astrophysics Data System (ADS)

Gallagher, M. E.; Hockaday, W. C.; Masiello, C. A.; Snapp, S.; Polley, W.; McSwiney, C. P.; Baldock, J.

2009-12-01

A fraction of fossil fuel carbon dioxide (CO2) emissions are being taken up by the terrestrial biosphere and the oceans. One particularly effective way of determining the sizes of these terrestrial biosphere and ocean carbon sinks is based on the measurements of changes in atmospheric oxygen (O2) and CO2 concentrations (Keeling et al. 1996). This method of carbon apportionment requires knowledge of total fossil fuel CO2 emissions, atmospheric O2 and CO2 concentrations, and the value of the terrestrial biosphere oxidative ratio (OR), which has historically been assumed to be constant at 1.10 (e.g. Prentice et al. 2001). OR is the ratio of moles of O2 per mole of CO2 in gas exchanges between the terrestrial biosphere and the atmosphere. An incorrect estimation of the biosphere’s OR results in misapportionment of CO2 between the terrestrial biosphere and ocean carbon sinks (Randerson et al. 2006). Understanding how OR can vary with changing environmental properties is therefore essential to accurately estimate the size of the terrestrial carbon sink. We estimate OR through its relationship with organic carbon oxidation state (Cox) measurements made using a 13C nuclear magnetic resonance spectrometer and a CHNSO elemental analyzer (Masiello et al. 2008; Hockaday et al. 2009). It is clear that ecosystem OR values frequently deviate from the assumed 1.10 (Masiello et al., 2008; Hockaday et al., 2009). Here we review what mechanisms drive shifts in OR, including: fire, climate (precipitation and temperature), land use change, atmospheric CO2 concentrations, and nutrient supply. We present data on the impact of nitrogen supply and elevated CO2 on ecosystem OR at two different field sites. We measure the effect of nitrogen supply on an agricultural ecosystem at the Kellogg Biological Station-Living Field Laboratory (KBS-LFL) in Michigan over a fertilization gradient (0 to 202 kg N/ha). We also measured the effect of atmospheric CO2 variation on ecosystem OR at a grassland site experiencing three atmospheric CO2 levels: pre-industrial, current, and projected (the USDA-Agricultural Research Service field site in Temple, Texas).

Elevated atmospheric CO2 affected photosynthetic products in wheat seedlings and biological activity in rhizosphere soil under cadmium stress.

PubMed

Jia, Xia; Liu, Tuo; Zhao, Yonghua; He, Yunhua; Yang, Mingyan

2016-01-01

The objective of this study was to investigate the effects of elevated CO2 (700 ± 23 μmol mol(-1)) on photosynthetic products in wheat seedlings and on organic compounds and biological activity in rhizosphere soil under cadmium (Cd) stress. Elevated CO2 was associated with decreased quantities of reducing sugars, starch, and soluble amino acids, and with increased quantities of soluble sugars, total sugars, and soluble proteins in wheat seedlings under Cd stress. The contents of total soluble sugars, total free amino acids, total soluble phenolic acids, and total organic acids in the rhizosphere soil under Cd stress were improved by elevated CO2. Compared to Cd stress alone, the activity of amylase, phenol oxidase, urease, L-asparaginase, β-glucosidase, neutral phosphatase, and fluorescein diacetate increased under elevated CO2 in combination with Cd stress; only cellulase activity decreased. Bacterial abundance in rhizosphere soil was stimulated by elevated CO2 at low Cd concentrations (1.31-5.31 mg Cd kg(-1) dry soil). Actinomycetes, total microbial abundance, and fungi decreased under the combined conditions at 5.31-10.31 mg Cd kg(-1) dry soil. In conclusion, increased production of soluble sugars, total sugars, and proteins in wheat seedlings under elevated CO2 + Cd stress led to greater quantities of organic compounds in the rhizosphere soil relative to seedlings grown under Cd stress only. Elevated CO2 concentrations could moderate the effects of heavy metal pollution on enzyme activity and microorganism abundance in rhizosphere soils, thus improving soil fertility and the microecological rhizosphere environment of wheat under Cd stress.

Increasing drought and diminishing benefits of elevated carbon dioxide for soybean yields across the US Midwest.

PubMed

Jin, Zhenong; Ainsworth, Elizabeth A; Leakey, Andrew D B; Lobell, David B

2018-02-01

Elevated atmospheric CO 2 concentrations ([CO 2 ]) are expected to increase C3 crop yield through the CO 2 fertilization effect (CFE) by stimulating photosynthesis and by reducing stomatal conductance and transpiration. The latter effect is widely believed to lead to greater benefits in dry rather than wet conditions, although some recent experimental evidence challenges this view. Here we used a process-based crop model, the Agricultural Production Systems sIMulator (APSIM), to quantify the contemporary and future CFE on soybean in one of its primary production area of the US Midwest. APSIM accurately reproduced experimental data from the Soybean Free-Air CO 2 Enrichment site showing that the CFE declined with increasing drought stress. This resulted from greater radiation use efficiency (RUE) and above-ground biomass production at elevated [CO 2 ] that outpaced gains in transpiration efficiency (TE). Using an ensemble of eight climate model projections, we found that drought frequency in the US Midwest is projected to increase from once every 5 years currently to once every other year by 2050. In addition to directly driving yield loss, greater drought also significantly limited the benefit from rising [CO 2 ]. This study provides a link between localized experiments and regional-scale modeling to highlight that increased drought frequency and severity pose a formidable challenge to maintaining soybean yield progress that is not offset by rising [CO 2 ] as previously anticipated. Evaluating the relative sensitivity of RUE and TE to elevated [CO 2 ] will be an important target for future modeling and experimental studies of climate change impacts and adaptation in C3 crops. © 2017 John Wiley & Sons Ltd.

Processes regulating progressive nitrogen limitation under elevated carbon dioxide: a meta-analysis

NASA Astrophysics Data System (ADS)

Liang, J.; Qi, X.; Souza, L.; Luo, Y.

2015-10-01

Nitrogen (N) cycle has the potential to regulate climate change through its influence on carbon (C) sequestration. Although extensive researches have been done to explore whether or not progressive N limitation (PNL) occurs under CO2 enrichment, a comprehensive assessment of the processes that regulate PNL is still lacking. Here, we quantitatively synthesized the responses of all major processes and pools in terrestrial N cycle with meta-analysis of CO2 experimental data available in the literature. The results showed that CO2 enrichment significantly increased N sequestration in plant and litter pools but not in soil pool. Thus, the basis of PNL occurrence partially exists. However, CO2 enrichment also significantly increased the N influx via biological N fixation, but decreased the N efflux via leaching. In addition, no general diminished CO2 fertilization effect on plant growth over time was observed. Overall, our analyses suggest that the extra N supply by the increased biological N fixation and decreased leaching may potentially alleviate PNL under elevated CO2 conditions. Moreover, our synthesis showed that CO2 enrichment increased soil ammonium (NH4+) but decreased nitrate (NO3-). The different responses of NH4+ and NO3-, and the consequent biological processes, may result in changes in soil microenvironment, community structures and above-belowground interactions, which could potentially affect the terrestrial biogeochemical cycles and the feedback to climate change.

Simple global carbon model: The atmosphere-terrestrial biosphere-ocean interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwon, O.Y.; Schnoor, J.L.

A simple global carbon model has been developed for scenario analysis, and research needs prioritization. CO{sub 2} fertilization and temperature effects are included in the terrestrial biosphere compartment, and the ocean compartment includes inorganic chemistry which, with ocean water circulation, enables the calculation of time-variable oceanic carbon uptake. Model-derived Q{sub 10} values (the increasing rate for every 10{degrees}C increase of temperature) are 1.37 for land biota photosynthesis, 1.89 for land biota respiration, and 1.95 for soil respiration, and feedback temperature is set at 0.01{degrees}C/ppm of CO{sub 2}. These could be the important parameters controlling the carbon cycle in potential globalmore » warming scenarios. Scenario analysis, together with sensitivity analysis of temperature feedback, suggests that if CO{sub 2} emissions from fossil fuel combustion continue at the present increasing rate of {approximately}1.5% per year, a CO{sub 2} doubling (to 560 ppm) will appear in year 2060. Global warming would be responsible for 40 Gt as carbon (Gt C) accumulation in the land biota, 88 Gt C depletion from the soil carbon, a 7 Gt C accumulation in the oceans, and a 19 ppm increase in atmospheric CO{sub 2}. The ocean buffering capacity to take up the excess CO{sub 2} will decrease with the increasing atmospheric CO{sub 2} concentration. 51 refs., 8 figs., 3 tabs.« less

The effect of improving cow productivity, fertility, and longevity on the global warming potential of dairy systems.

PubMed

Bell, M J; Wall, E; Russell, G; Simm, G; Stott, A W

2011-07-01

This study compared the environmental impact of a range of dairy production systems in terms of their global warming potential (GWP, expressed as carbon dioxide equivalents, CO(2)-eq.) and associated land use, and explored the efficacy of reducing said impact. Models were developed using the unique data generated from a long-term genetic line × feeding system experiment. Holstein-Friesian cows were selected to represent the UK average for milk fat plus protein production (control line) or were selected for increased milk fat plus protein production (select line). In addition, cows received a low forage diet (50% forage) with no grazing or were on a high forage (75% forage) diet with summer grazing. A Markov chain approach was used to describe the herd structure and help estimate the GWP per year and land required per cow for the 4 alternative systems and the herd average using a partial life cycle assessment. The CO(2)-eq. emissions were expressed per kilogram of energy-corrected milk (ECM) and per hectare of land use, as well as land required per kilogram of ECM. The effects of a phenotypic and genetic standard deviation unit improvement on herd feed utilization efficiency, ECM yield, calving interval length, and incidence of involuntary culling were assessed. The low forage (nongrazing) feeding system with select cows produced the lowest CO(2)-eq. emissions of 1.1 kg/kg of ECM and land use of 0.65 m(2)/kg of ECM but the highest CO(2)-eq. emissions of 16.1t/ha of the production systems studied. Within the herd, an improvement of 1 standard deviation in feed utilization efficiency was the only trait of those studied that would significantly reduce the reliance of the farming system on bought-in synthetic fertilizer and concentrate feed, as well as reduce the average CO(2)-eq. emissions and land use of the herd (both by about 6.5%, of which about 4% would be achievable through selective breeding). Within production systems, reductions in CO(2)-eq. emissions per kilogram of ECM and CO(2)-eq. emissions per hectare were also achievable by an improvement in feed utilization. This study allowed development of models that harness the biological trait variation in the animal to improve the environmental impact of the farming system. Genetic selection for efficient feed use for milk production according to feeding system can bring about reductions in system nutrient requirements, CO(2)-eq. emissions, and land use per unit product. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

RADIATION GENETICS IN WHEAT. VII. COMPARISON OF RADIATION EFFECTS OF BETA- AND GAMMA-RAYS ON DIPLOID WHEAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumura, S.

1962-01-01

Seeds of Triticum monococcum flavescens were soaked in P/sup 32/ and I/ sup 131/solutions for 2 days before sowing, to compare the effects of beta and gamma radiations. Radioactive solutions of pH 6-7 contained 0.05-0.8 mc/gr P/sup 32/ and 0.2--0.8 mc/g I/sup 131/. For comparison, seeds soaked in water for 2 days were exposed to gamma radiation with Co/sup 60/ at the dosages 2.5, 5, 10, and 20 kr. The growth of seedlings, height of mature plants, single-spike fertility, and chromosome aberrations of treated plants in X/sub 1/ and chlorophyll mutations in X/sub 2/ were compared for beta and gammamore » irradiation. The higher the dosage of beta and gamma rays, the more delayed were emergence and growth of seedlings and the lower were survival rate, height of mature plants, and fertility. The relation between the inhibition of seedling growth and dosage of beta and gamma radiations coincides roughly with that between the decrease of survival rate or- fertility and dosage. There was no emergence of seedlings at 20 kr gamma radiation and 0.8 mc/g P/sup 32/ beta radiation. The effects of beta radiation from 0.15-0.2 mc/g P/sup 32/ and 0.8 mc/g I/sup 131/ solutions correspond roughly to those of 2.5 kr gamma radiation. As to chromosome aberrations and chlorophyll mutations, the effects of 2.5 kr gamma radiation coincide roughly with those of 0.1 mc/g P/sup 32/ and 0.6-0.8 mc/g I/sup 131/ solution. If it is assumed that the effects of beta radiation are confined only to the embryo, then a 0.2 mc/g P/sup 32/ solution equals about 2.4 krad. This will account for the present data. (auth)« less

Trace element contaminants in mineral fertilizers used in Iran.

PubMed

Latifi, Zahra; Jalali, Mohsen

2018-05-25

The application of mineral fertilizers which have contaminants of trace elements may impose concern regarding the entry and toxic accumulation of these elements in agro-ecosystems. In this study, 57 mineral fertilizers (nitrogen, potassium, phosphate, and compound fertilizers) distributed in Iran were analyzed for their contents of Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, and Fe. The results revealed that the contents of these trace elements varied considerably depending on the type of the element and the fertilizer. Among these elements, Fe displayed the highest average content, whereas Cd showed the lowest. Generally, the trace element contents in P-containing fertilizers were higher than those in nitrogen and potassium fertilizers. The mean values of trace elements (mg kg -1 ) in P-containing fertilizers were 4.0 (Cd), 5.5 (Co), 35.7 (Cr), 24.4 (Cu), 272 (Mn), 14.3 (Ni), 6.0 (Pb), 226 (Zn), and 2532 (Fe). Comparing trace element contents to limit values set by the German Fertilizer Ordinance showed that the mean contents of potentially toxic trace elements, such as Cd and Pb, were lower than their limit values in all groups of fertilizers. On the other hand, while a number of fertilizers contained a high content of some essential trace elements, particularly Fe, they were not labeled as such.

Evaluating the need for integrated land use and land cover analysis for robust assessment of climate adaptation and mitigation strategies

NASA Astrophysics Data System (ADS)

Di Vittorio, Alan; Mao, Jiafu; Shi, Xiaoying

2016-04-01

Several climate adaptation and mitigation strategies incorporate land use and land cover change to address global carbon balance and also food, fuel, fiber, and water resource sustainability. However, Land Use and Land Cover Change (LULCC) are not consistent across the CMIP5 model simulations because only the land use input was harmonized. Differences in LULCC impede understanding of global change because such differences can dramatically alter land-atmosphere mass and energy exchange in response to differences in associated use and distribution of land resources. For example, the Community Earth System Model (CESM) overestimates 2005 atmospheric CO2 concentration by 18 ppmv, and we explore the contribution of historical LULCC to this bias in relation to the effects of CO2 fertilization and nitrogen deposition on terrestrial carbon. Using identical land use input, a chronologically referenced LULCC that accounts for pasture, as opposed to the default year-2000 referenced LULCC, increases this bias to 27 ppmv because more forest needs to be cleared for land use. Assuming maximum forest retention for all land conversion reduces the new bias to ~21 ppmv, while minimum forest retention increases the new bias to ~32 ppmv. Corresponding ecosystem carbon changes from the default in 2005 are approximately -28 PgC, -10 PgC, and -43 PgC, respectively. This 33 PgC uncertainty range due to maximizing versus minimizing forest area is 66% of the estimated 50 PgC gain in ecosystem carbon due to CO2 fertilization from 1850-2005, and 150% of the estimated 22 PgC gain due to nitrogen deposition. This range is also similar to the 28 PgC difference generated by changing the LULCC reference year and accounting for pasture. These results indicate that LULCC uncertainty is not only a major driver of bias in simulated atmospheric CO2, but that it could contribute even more to this bias than uncertainty in CO2 fertilization or nitrogen deposition. This highlights the need for more accurate LULCC scenarios in earth system simulations to provide robust historical and future projections of carbon and climate, especially when incorporating climate feedbacks on human and environmental systems. More accurate LULCC scenarios will also improve impact and resource sustainability analyses in the context of climate adaptation and mitigation strategies. These new scenarios will need to be developed and implemented as an integrated process with interdependent land use and land cover to adequately incorporate human and environmental drivers of LULCC.

Long-term influence of tillage and fertilization on net carbon dioxide exchange rate on two soils with different textures.

PubMed

Feiziene, Dalia; Feiza, Virginijus; Slepetiene, Alvyra; Liaudanskiene, Inga; Kadziene, Grazina; Deveikyte, Irena; Vaideliene, Asta

2011-01-01

The importance of agricultural practices to greenhouse gas mitigation is examined worldwide. However, there is no consensus on soil organic carbon (SOC) content and CO emissions as affected by soil management practices and their relationships with soil texture. No-till (NT) agriculture often results in soil C gain, though, not always. Soil net CO exchange rate (NCER) and environmental factors (SOC, soil temperature [T], and water content [W]), as affected by soil type (loam and sandy loam), tillage (conventional, reduced, and NT), and fertilization, were quantified in long-term field experiments in Lithuania. Soil tillage and fertilization affected total CO flux (heterotrophic and autotrophic) through effect on soil SOC sequestration, water, and temperature regime. After 11 yr of different tillage and fertilization management, SOC content was 23% more in loam than in sandy loam. Long-term NT contributed to 7 to 27% more SOC sequestration on loam and to 29 to 33% more on sandy loam compared with reduced tillage (RT) or conventional tillage (CT). Soil water content in loam was 7% more than in sandy loam. Soil gravimetric water content, averaged across measurement dates and fertilization treatments, was significantly less in NT than CT and RT in both soils. Soil organic carbon content and water storage capacity of the loam and sandy loam soils exerted different influences on NCER. The NCER from the sandy loam soil was 13% greater than that from the loam. In addition, NCER was 4 to 9% less with NT than with CT and RT systems on both loam and sandy loam soils. Application of mineral NPK fertilizers promoted significantly greater NCER from loam but suppressed NCER by 15% from sandy loam. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Long-term fertilization of a boreal Norway spruce forest increases the temperature sensitivity of soil organic carbon mineralization

PubMed Central

Coucheney, Elsa; Strömgren, Monika; Lerch, Thomas Z; Herrmann, Anke M

2013-01-01

Boreal ecosystems store one-third of global soil organic carbon (SOC) and are particularly sensitive to climate warming and higher nutrient inputs. Thus, a better description of how forest managements such as nutrient fertilization impact soil carbon (C) and its temperature sensitivity is needed to better predict feedbacks between C cycling and climate. The temperature sensitivity of in situ soil C respiration was investigated in a boreal forest, which has received long-term nutrient fertilization (22 years), and compared with the temperature sensitivity of C mineralization measured in the laboratory. We found that the fertilization treatment increased both the response of soil in situ CO2 effluxes to a warming treatment and the temperature sensitivity of C mineralization measured in the laboratory (Q10). These results suggested that soil C may be more sensitive to an increase in temperature in long-term fertilized in comparison with nutrient poor boreal ecosystems. Furthermore, the fertilization treatment modified the SOC content and the microbial community composition, but we found no direct relationship between either SOC or microbial changes and the temperature sensitivity of C mineralization. However, the relation between the soil C:N ratio and the fungal/bacterial ratio was changed in the combined warmed and fertilized treatment compared with the other treatments, which suggest that strong interaction mechanisms may occur between nutrient input and warming in boreal soils. Further research is needed to unravel into more details in how far soil organic matter and microbial community composition changes are responsible for the change in the temperature sensitivity of soil C under increasing mineral N inputs. Such research would help to take into account the effect of fertilization managements on soil C storage in C cycling numerical models. PMID:24455147

Effects of phosphorus fertilizer and lime on the As, Cr, Pb, and V content of soils and plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodroad, L.L.; Caldwell, A.C.

1979-10-01

The occurrence in fertilizer material of small quantities of chemical elements not essential to plants suggests that the soil may become contaminated with these elements due to the use of fertilizers. Two experimental sites: a Nicollet clay loam fertilized with 0, 1111, 2222, 4444, and 8888 kg/ha of concentrated superphosphate (CSP) and 20.2 metric tons of lime, and a Port Byron silt loam fertilized for 19 years with 99, 73, 82, and 352 kg/ha annually of CSP, calcium metaphosphate, phosphoric acid, and southern rock phosphate, respectively, were sampled to determine if significant amounts of arsenic (As), chromium (Cr), lead (Pb),more » or vanadium (V) had been added from the use of these fertilizer materials. There was no indication of increased As, Cr, Pb, or V from the addition of P fertilizers to either the Nicollet or Port Byron soils. The addition of lime increased the Cr content of the Nicollet soil by approximately 3 ppM, but there was no increase in As, Pb, or V. There was no increase in As, Cr, Pb, or V from addition of CSP in soil samples from below the Ap horizon to a depth of 47.5 cm. Soil samples from a representative Nicollet soil suggest that higher As, Cr, Pb, and V concentrations in the A and B horizons are due to leaching of CaCO/sub 3/ into the C horizon. Corn (Zea mays L.) plant growth and grain yields were similar for all CSP and lime treatments. The results of this study indicate that the use of P fertilizers at the rates presently applied would not add substantially to the natural levels of As, Cr, Pb, and V in the soil.« less

Nitrous oxide emission reduction in temperate biochar-amended soils

NASA Astrophysics Data System (ADS)

Felber, R.; Hüppi, R.; Leifeld, J.; Neftel, A.

2012-01-01

Biochar, a pyrolysis product of organic residues, is an amendment for agricultural soils to improve soil fertility, sequester CO2 and reduce greenhouse gas (GHG) emissions. In highly weathered tropical soils laboratory incubations of soil-biochar mixtures revealed substantial reductions for nitrous oxide (N2O) and carbon dioxide (CO2). In contrast, evidence is scarce for temperate soils. In a three-factorial laboratory incubation experiment two different temperate agricultural soils were amended with green waste and coffee grounds biochar. N2O and CO2 emissions were measured at the beginning and end of a three month incubation. The experiments were conducted under three different conditions (no additional nutrients, glucose addition, and nitrate and glucose addition) representing different field conditions. We found mean N2O emission reductions of 60 % compared to soils without addition of biochar. The reduction depended on biochar type and soil type as well as on the age of the samples. CO2 emissions were slightly reduced, too. NO3- but not NH4+ concentrations were significantly reduced shortly after biochar incorporation. Despite the highly significant suppression of N2O emissions biochar effects should not be transferred one-to-one to field conditions but need to be tested accordingly.

Sulfur and Zinc Availability from Co-granulated Zn-Enriched Elemental Sulfur Fertilizers.

PubMed

Mattiello, Edson M; da Silva, Rodrigo C; Degryse, Fien; Baird, Roslyn; Gupta, Vadakattu V S R; McLaughlin, Michael J

2017-02-15

Acidification by oxidation of elemental sulfur (ES) can solubilize ZnO, providing slow release of both sulfur (S) and zinc (Zn) in soil. For this study, a new granular fertilizer with ES and ZnO was produced and evaluated. The effect of incorporating microorganisms or a carbon source in the granule was also evaluated. Four granulated ES-Zn fertilizers with and without S-oxidizing microorganisms, a commercial ES pastille, ZnSO 4 , and ZnO were applied to the center of Petri dishes containing two contrasting pH soils. Soil pH, CaCl 2 -extractable S and Zn, and remaining ES were evaluated at 30 and 60 days in two soil sections (0-5 and 5-9 mm from the fertilizer application site). A visualization test was performed to evaluate Zn diffusion over time. A significant pH decrease was observed in the acidic soil for all ES-Zn fertilizer treatments and in the alkaline soil for the Acidithiobacillus thiooxidans-inoculated treatment only. In agreement with Zn visualization tests, extractable-Zn concentrations were higher from the point of application in the acidic (62.9 mg dm -3 ) compared to the alkaline soil (5.5 mg dm -3 ). Elemental S oxidation was greater in the acidic soil (20.9%) than slightly alkaline soil (12%). The ES-Zn granular fertilizers increased S and Zn concentrations in soil and can provide a strategically slow release of nutrients to the soil.

Modelling female fertility traits in beef cattle using linear and non-linear models.

PubMed

Naya, H; Peñagaricano, F; Urioste, J I

2017-06-01

Female fertility traits are key components of the profitability of beef cattle production. However, these traits are difficult and expensive to measure, particularly under extensive pastoral conditions, and consequently, fertility records are in general scarce and somehow incomplete. Moreover, fertility traits are usually dominated by the effects of herd-year environment, and it is generally assumed that relatively small margins are kept for genetic improvement. New ways of modelling genetic variation in these traits are needed. Inspired in the methodological developments made by Prof. Daniel Gianola and co-workers, we assayed linear (Gaussian), Poisson, probit (threshold), censored Poisson and censored Gaussian models to three different kinds of endpoints, namely calving success (CS), number of days from first calving (CD) and number of failed oestrus (FE). For models involving FE and CS, non-linear models overperformed their linear counterparts. For models derived from CD, linear versions displayed better adjustment than the non-linear counterparts. Non-linear models showed consistently higher estimates of heritability and repeatability in all cases (h 2  < 0.08 and r < 0.13, for linear models; h 2  > 0.23 and r > 0.24, for non-linear models). While additive and permanent environment effects showed highly favourable correlations between all models (>0.789), consistency in selecting the 10% best sires showed important differences, mainly amongst the considered endpoints (FE, CS and CD). In consequence, endpoints should be considered as modelling different underlying genetic effects, with linear models more appropriate to describe CD and non-linear models better for FE and CS. © 2017 Blackwell Verlag GmbH.

The beneficial effects of cumulus cells and oocyte-cumulus cell gap junctions depends on oocyte maturation and fertilization methods in mice.

PubMed

Zhou, Cheng-Jie; Wu, Sha-Na; Shen, Jiang-Peng; Wang, Dong-Hui; Kong, Xiang-Wei; Lu, Angeleem; Li, Yan-Jiao; Zhou, Hong-Xia; Zhao, Yue-Fang; Liang, Cheng-Guang

2016-01-01

Cumulus cells are a group of closely associated granulosa cells that surround and nourish oocytes. Previous studies have shown that cumulus cells contribute to oocyte maturation and fertilization through gap junction communication. However, it is not known how this gap junction signaling affects in vivo versus in vitro maturation of oocytes, and their subsequent fertilization and embryonic development following insemination. Therefore, in our study, we performed mouse oocyte maturation and insemination using in vivo- or in vitro-matured oocyte-cumulus complexes (OCCs, which retain gap junctions between the cumulus cells and the oocytes), in vitro-matured, denuded oocytes co-cultured with cumulus cells (DCs, which lack gap junctions between the cumulus cells and the oocytes), and in vitro-matured, denuded oocytes without cumulus cells (DOs). Using these models, we were able to analyze the effects of gap junction signaling on oocyte maturation, fertilization, and early embryo development. We found that gap junctions were necessary for both in vivo and in vitro oocyte maturation. In addition, for oocytes matured in vivo, the presence of cumulus cells during insemination improved fertilization and blastocyst formation, and this improvement was strengthened by gap junctions. Moreover, for oocytes matured in vitro, the presence of cumulus cells during insemination improved fertilization, but not blastocyst formation, and this improvement was independent of gap junctions. Our results demonstrate, for the first time, that the beneficial effect of gap junction signaling from cumulus cells depends on oocyte maturation and fertilization methods.

Coupled nutrient cycling determines tropical forest trajectory under elevated CO2.

NASA Astrophysics Data System (ADS)

Bouskill, N.; Zhu, Q.; Riley, W. J.

2017-12-01

Tropical forests have a disproportionate capacity to affect Earth's climate relative to their areal extent. Despite covering just 12 % of land surface, tropical forests account for 35 % of global net primary productivity and are among the most significant of terrestrial carbon stores. As atmospheric CO2 concentrations increase over the next century, the capacity of tropical forests to assimilate and sequester anthropogenic CO2 depends on limitation by multiple factors, including the availability of soil nutrients. Phosphorus availability has been considered to be the primary factor limiting metabolic processes within tropical forests. However, recent evidence points towards strong spatial and temporal co-limitation of tropical forests by both nitrogen and phosphorus. Here, we use the Accelerated Climate Modeling for Energy (ACME) Land Model (ALMv1-ECA-CNP) to examine how nutrient cycles interact and affect the trajectory of the tropical forest carbon sink under, (i) external nutrient input, (ii) climate (iii) elevated CO2, and (iv) a combination of 1-3. ALMv1 includes recent theoretical advances in representing belowground competition between roots, microbes and minerals for N and P uptake, explicit interactions between the nitrogen and phosphorus cycles (e.g., phosphatase production and nitrogen fixation), the dynamic internal allocation of plant N and P resources, and the integration of global datasets of plant physiological traits. We report nutrient fertilization (N, P, N+P) predictions for four sites in the tropics (El Verde, Puerto Rico, Barro Colorado Island, Panama, Manaus, Brazil and the Osa Peninsula, Coast Rica) to short-term nutrient fertilization (N, P, N+P), and benchmarking of the model against a meta-analysis of forest fertilization experiments. Subsequent simulations focus on the interaction of the carbon, nitrogen, and phosphorus cycles across the tropics with a focus on the implications of coupled nutrient cycling and the fate of the tropical forest carbon sink. Our results highlight the importance of transient CNP allocation, leaf-level stoichiometric controls on photosynthesis, and trade-offs between above and belowground plant investments.

Simulated ocean acidification reveals winners and losers in coastal phytoplankton.

PubMed

Bach, Lennart T; Alvarez-Fernandez, Santiago; Hornick, Thomas; Stuhr, Annegret; Riebesell, Ulf

2017-01-01

The oceans absorb ~25% of the annual anthropogenic CO2 emissions. This causes a shift in the marine carbonate chemistry termed ocean acidification (OA). OA is expected to influence metabolic processes in phytoplankton species but it is unclear how the combination of individual physiological changes alters the structure of entire phytoplankton communities. To investigate this, we deployed ten pelagic mesocosms (volume ~50 m3) for 113 days at the west coast of Sweden and simulated OA (pCO2 = 760 μatm) in five of them while the other five served as controls (380 μatm). We found: (1) Bulk chlorophyll a concentration and 10 out of 16 investigated phytoplankton groups were significantly and mostly positively affected by elevated CO2 concentrations. However, CO2 effects on abundance or biomass were generally subtle and present only during certain succession stages. (2) Some of the CO2-affected phytoplankton groups seemed to respond directly to altered carbonate chemistry (e.g. diatoms) while others (e.g. Synechococcus) were more likely to be indirectly affected through CO2 sensitive competitors or grazers. (3) Picoeukaryotic phytoplankton (0.2-2 μm) showed the clearest and relatively strong positive CO2 responses during several succession stages. We attribute this not only to a CO2 fertilization of their photosynthetic apparatus but also to an increased nutrient competitiveness under acidified (i.e. low pH) conditions. The stimulating influence of high CO2/low pH on picoeukaryote abundance observed in this experiment is strikingly consistent with results from previous studies, suggesting that picoeukaryotes are among the winners in a future ocean.

Simulated ocean acidification reveals winners and losers in coastal phytoplankton

PubMed Central

Alvarez-Fernandez, Santiago; Hornick, Thomas; Stuhr, Annegret; Riebesell, Ulf

2017-01-01

The oceans absorb ~25% of the annual anthropogenic CO2 emissions. This causes a shift in the marine carbonate chemistry termed ocean acidification (OA). OA is expected to influence metabolic processes in phytoplankton species but it is unclear how the combination of individual physiological changes alters the structure of entire phytoplankton communities. To investigate this, we deployed ten pelagic mesocosms (volume ~50 m3) for 113 days at the west coast of Sweden and simulated OA (pCO2 = 760 μatm) in five of them while the other five served as controls (380 μatm). We found: (1) Bulk chlorophyll a concentration and 10 out of 16 investigated phytoplankton groups were significantly and mostly positively affected by elevated CO2 concentrations. However, CO2 effects on abundance or biomass were generally subtle and present only during certain succession stages. (2) Some of the CO2-affected phytoplankton groups seemed to respond directly to altered carbonate chemistry (e.g. diatoms) while others (e.g. Synechococcus) were more likely to be indirectly affected through CO2 sensitive competitors or grazers. (3) Picoeukaryotic phytoplankton (0.2–2 μm) showed the clearest and relatively strong positive CO2 responses during several succession stages. We attribute this not only to a CO2 fertilization of their photosynthetic apparatus but also to an increased nutrient competitiveness under acidified (i.e. low pH) conditions. The stimulating influence of high CO2/low pH on picoeukaryote abundance observed in this experiment is strikingly consistent with results from previous studies, suggesting that picoeukaryotes are among the winners in a future ocean. PMID:29190760

Bioenergy residues applied as soil amendments: N2O emissions and C sequestration potential

NASA Astrophysics Data System (ADS)

Cayuela, M.; Kuikman, P.; Oenema, O.; Bakker, R.; van Groenigen, J.

2009-12-01

Biofuels have been proposed as environmentally benign substitutes to fossil fuels. There is, however, substantial uncertainty in the scientific literature about how an expanding bioenergy sector would interact with other land uses and what could be the environmental consequences. In the particular case of greenhouse gas balance, the magnitude of discrepancy is tremendously high among different studies. Such controversy has been often attributed to the way the co-products generated were accounted for. It is likely that the intensification of bioenergy production will lead to an increased input of these co-products to the soil as alternative amendments or fertilizers. However, limited research has been done to determine how this will influence microbial transformation processes in soil and thereby the emissions of greenhouse gases. Neither have related issues such as the stabilization of soil organic matter, soil structure and soil fertility been adequately studied. Here, we report a laboratory study on the effects of the application of bioenergy residues on C and N mineralization and greenhouse gas emissions in an agricultural soil. Ten co-products were selected from different energy sectors: anaerobic digestion (digestates), first generation biofuel residues (rapeseed meal, distilled dried grains with solubles), second generation biofuel residues (non-fermentables from hydrolysis of different lignocellulosic materials) and pyrolysis (biochars). They were added at the same N rate (150 kg N ha-1) to a moist (80% water filled pore space) sandy soil and incubated at 20 C for 60 days. Most residues followed fast mineralization dynamics with a flush of CO2 respiration within the first week. The biochars were the exception: they showed very low respiration rates. After 60 days, first generation biofuel residues had emitted more than 80% of added C as CO2. Around 60% was emitted in the case of second generation biofuel residues and 40% with digestates. Biochars were the most stable residues with the lowest CO2 loss between 0.5 and 5.8 % of total added C. Regarding N2O emissions, first generation biofuel residues led to the highest total N2O emissions (between 2.5 - 6.0% of added N). Second generation biofuel residues emitted between 1.0-2.0% of added N, whereas anaerobic digestates led to emissions lower than 1% of added N. The two biochars used in this study led to negative N2O emissions, i.e. lower than the blank soil. We conclude that, at least in the short term, the effects of biofuel residues on the combined greenhouse gas balance of the soil ranges from beneficial (biochar) via mixed (digestates, second generation biofuels) to manifestly detrimental (first generation biofuels). These effects should be taken into account in life cycle analyses of biofuel production.

Plant growth improvement mediated by nitrate capture in co-composted biochar.

PubMed

Kammann, Claudia I; Schmidt, Hans-Peter; Messerschmidt, Nicole; Linsel, Sebastian; Steffens, Diedrich; Müller, Christoph; Koyro, Hans-Werner; Conte, Pellegrino; Joseph, Stephen; Stephen, Joseph

2015-06-09

Soil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting considerably promoted biochars' positive effects, largely by nitrate (nutrient) capture and delivery. In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a sandy-poor soil amended with 2% (w/w) co-composted biochar (BC(comp)). Conversely, addition of 2% (w/w) untreated biochar (BC(pure)) decreased the biomass to 60% of the control. Growth-promoting (BC(comp)) as well as growth-reducing (BC(pure)) effects were more pronounced at lower nutrient-supply levels. Electro-ultra filtration and sequential biochar-particle washing revealed that co-composted biochar was nutrient-enriched, particularly with the anions nitrate and phosphate. The captured nitrate in BC(comp) was (1) only partly detectable with standard methods, (2) largely protected against leaching, (3) partly plant-available, and (4) did not stimulate N2O emissions. We hypothesize that surface ageing plus non-conventional ion-water bonding in micro- and nano-pores promoted nitrate capture in biochar particles. Amending (N-rich) bio-waste with biochar may enhance its agronomic value and reduce nutrient losses from bio-wastes and agricultural soils.

DMPP-added nitrogen fertilizer affects soil N2O emission and microbial activity in Southern Italy

NASA Astrophysics Data System (ADS)

Vitale, Luca; De Marco, Anna; Maglione, Giuseppe; Polimeno, Franca; Di Tommasi, Paul; Magliulo, Vincenzo

2014-05-01

Arable sites contributes to global N2O emission due to massive utilization of nitrogen fertilizers. N2O derives from the biological processes such as nitrification and denitrification influenced by soil nitrogen availability. The use of nitrogen fertilizers added with nitrification inhibitors represents one among the proposed strategy to reduce soil N2O emission form arable sites. The aim of this work was to evaluate the effects of 3,4-dimethylphyrazole phosphate (DMPP), a nitrification inhibitor, on N2O emission and microbial activity of a soil cropped to potato in Southern Italy. The experiment was a randomized block design with two treatments applied and three replicates: control (C) and DMPP (Entec®, K+S Nitrogen) plots, both supplied with the same amount of ammonium nitrate. The nitrogen fertilizer was supplied in three events: at 0 Day After Sowing (DAS; 100 kg N ha-1), at 57 DAS (30 kg N ha-1), and at 71 DAS (30 kg N ha-1). Soil N2O emission was monitored by both dynamic and static chambers. Static chambers were located both on hills and furrows whereas dynamic chambers were located on furrows. Air samples were collected from chambers at different times and analysed by a gas chromatograph (SRI 8610C, Gas Chromatograph). Fluxes were estimated as a linear interpolation of N2O changes over a 30 min time. Microbial biomass and basal respiration were determined as CO2 evolution, analysed by means of an IRGA (Li6200, Licor), on 2 g of fresh soil over a 4h incubation time. Microbial biomass was determined by Substrate Induced Respiration method. Data show no statistical differences in N2O fluxes measured with either dynamic chambers between C and DMPP plots in studied period. However, after the first fertilization event, when the fertilizer was applied as 100 kg N ha-1, the average N2O fluxes measured with static chambers were higher in DMPP plots compared to C plots. In the same period, the microbial biomass significantly decreased in DMPP plots as compared to C plots, whereas an opposite trend for basal respiration was observed, thus evidencing a stressful condition for nitrifying microbial population. After 57 and 71 DAS, when fertilizer was applied as 30 kg N ha-1, the microbial biomass was similar between C and DMPP plots, whereas basal respiration resulted statistically lower in DMPP plots than C plots. During these periods, average DMPP N2O fluxes were also comparable or lower. In conclusion, our data evidence a stressful condition for soil microbes and in particular for nitrifiers when a higher DMPP quantity is supplied. On the contrary, when lower quantities of DMPP-added fertilizers are supplied (e.s. 30 kg N ha-1) effectiveness of DMPP in reducing soil N2O emission is guaranteed by reducing the nitrifiers activity without negatively affecting their growth.

Long-term nutrient fertilization and the carbon balance of permanent grassland: any evidence for sustainable intensification?

NASA Astrophysics Data System (ADS)

Fornara, Dario A.; Wasson, Elizabeth-Anne; Christie, Peter; Watson, Catherine J.

2016-09-01

Sustainable grassland intensification aims to increase plant yields while maintaining the ability of soil to act as a sink rather than sources of atmospheric CO2. High biomass yields from managed grasslands, however, can be only maintained through long-term nutrient fertilization, which can significantly affect soil carbon (C) storage and cycling. Key questions remain about (1) how long-term inorganic vs. organic fertilization influences soil C stocks, and (2) how soil C gains (or losses) contribute to the long-term C balance of managed grasslands. Using 43 years of data from a permanent grassland experiment, we show that soils not only act as significant C sinks but have not yet reached C saturation. Even unfertilized control soils showed C sequestration rates of 0.35 Mg C ha-1 yr-1 (i.e. 35 g C m-2 yr-1; 0-15 cm depth) between 1970 and 2013. High application rates of liquid manure (i.e. cattle slurry) further increased soil C sequestration to 0.86 Mg C ha-1 yr-1 (i.e. 86 g C m-2 yr-1) and a key cause of this C accrual was greater C inputs from cattle slurry. However, average coefficients of slurry-C retention in soils suggest that 85 % of C added yearly through liquid manure is lost possibly via CO2 fluxes and organic C leaching. Inorganically fertilized soils (i.e. NPK) had the lowest C-gain efficiency (i.e. unit of C gained per unit of N added) and lowest C sequestration (similar to control soils). Soils receiving cattle slurry showed higher C-gain and N-retention efficiencies compared to soils receiving NPK or pig slurry. We estimate that net rates of CO2-sequestration in the top 15 cm of the soil can offset 9-25 % of GHG (greenhouse gas) emissions from intensive management. However, because of multiple GHG sources associated with livestock farming, the net C balance of these grasslands remains positive (9-12 Mg CO2-equivalent ha-1 yr-1), thus contributing to climate change. Further C-gain efficiencies (e.g. reduced enteric fermentation and use of feed concentrates, better nutrient management) are required to make grassland intensification more sustainable.

Physiological and Transcriptome Responses to Combinations of Elevated CO2 and Magnesium in Arabidopsis thaliana

PubMed Central

Niu, Yaofang; Ahammed, Golam Jalal; Tang, Caixian; Guo, Longbiao; Yu, Jingquan

2016-01-01

The unprecedented rise in atmospheric CO2 concentration and injudicious fertilization or heterogeneous distribution of Mg in the soil warrant further research to understand the synergistic and holistic mechanisms involved in the plant growth regulation. This study investigated the influence of elevated CO2 (800 μL L−1) on physiological and transcriptomic profiles in Arabidopsis cultured in hydroponic media treated with 1 μM (low), 1000 μM (normal) and 10000 μM (high) Mg2+. Following 7-d treatment, elevated CO2 increased the shoot growth and chlorophyll content under both low and normal Mg supply, whereas root growth was improved exclusively under normal Mg nutrition. Notably, the effect of elevated CO2 on mineral homeostasis in both shoots and roots was less than that of Mg supply. Irrespective of CO2 treatment, high Mg increased number of young leaf but decreased root growth and absorption of P, K, Ca, Fe and Mn whereas low Mg increased the concentration of P, K, Ca and Fe in leaves. Transcriptomics results showed that elevated CO2 decreased the expression of genes related to cell redox homeostasis, cadmium response, and lipid localization, but enhanced signal transduction, protein phosphorylation, NBS-LRR disease resistance proteins and subsequently programmed cell death in low-Mg shoots. By comparison, elevated CO2 enhanced the response of lipid localization (mainly LTP transfer protein/protease inhibitor), endomembrane system, heme binding and cell wall modification in high-Mg roots. Some of these transcriptomic results are substantially in accordance with our physiological and/or biochemical analysis. The present findings broaden our current understanding on the interactive effect of elevated CO2 and Mg levels in the Arabidopsis, which may help to design the novel metabolic engineering strategies to cope with Mg deficiency/excess in crops under elevated CO2. PMID:26881808

Millennial-scale iron fertilization of the eastern equatorial Pacific over the past 100,000 years

NASA Astrophysics Data System (ADS)

Loveley, Matthew R.; Marcantonio, Franco; Wisler, Marilyn M.; Hertzberg, Jennifer E.; Schmidt, Matthew W.; Lyle, Mitchell

2017-10-01

The eastern equatorial Pacific Ocean plays a crucial role in global climate, as it is a substantial source of CO2 to the atmosphere and accounts for a significant portion of global new export productivity. Here we present a 100,000-year sediment core from the eastern equatorial Pacific, and reconstruct dust flux, export productivity and bottom-water oxygenation using excess-230Th-derived fluxes of 232Th and barium, and authigenic uranium concentrations, respectively. We find that during the last glacial period (71,000 to 41,000 years ago), increased delivery of dust to the eastern equatorial Pacific was coeval with North Atlantic Heinrich stadial events. Millennial-scale pulses of increased dust flux coincided with episodes of heightened biological productivity, suggesting that dissolution of dust released iron that promoted ocean fertilization. We also find that periods of low atmospheric CO2 concentrations were associated with suboxic conditions and increased storage of respired carbon in the deep eastern equatorial Pacific. Increases in CO2 concentrations during the deglaciation are coincident with increases in deep Pacific and Southern Ocean water oxygenation levels. We suggest that deep-ocean ventilation was a primary control on CO2 outgassing in this region, with superimposed pulses of high productivity providing a negative feedback.

Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia.

PubMed

Alshahri, Fatimh; Alqahtani, Muna

2015-06-01

The specific activities of (238)U, (226)Ra, (40)K, and (222)Rn in chemical fertilizers were measured using gamma ray spectrometer and Cr-39 detector. In this study, 21 chemical fertilizers were collected from Eastern Saudi Arabian markets. The specific activities of (238)U ranged from 23 ± 0.5 to 3900 ± 195 Bq kg(-1); (226)Ra ranged from 5.60 ± 2.80 to 392 ± 18 Bq kg(-1); and (40)K ranged from 18.4 ± 3 to 16,476 ± 820 Bq kg(-1). The radon concentrations and the radon exhalation rates were found to vary from 3.20 ± 1.20 to 1532 ± 160 Bq m(-3) and from 1.60 to 774 mBq m(-2) h(-1), respectively. Radium equivalent activities (Raeq) were calculated for the analyzed samples to assess the radiation hazards arising due to the use of these chemical fertilizers in the agriculture soil. The Raeq for six local samples (nitrogen, phosphorous, and potassium (NPK) and single superphosphate (SSP)) and one imported sample (Sulfate of Potash (SOP)) were greater than the acceptable value 370 Bq kg(-1). The total air absorbed doses rates in air 1 m above the ground (D) were calculated for all samples. All samples, except one imported granule sample diammonium phosphate (DAP), were higher than the estimated average global terrestrial radiation of 55 nGy h(-1). The highest annual effective dose was in triple super phosphate (TSP) fertilizers (2.1 mSv y(-1)). The results show that the local TSP, imported SOP, and local NPK (sample 13) fertilizers were unacceptable for use as fertilizers in agricultural soil. Furthermore, the toxic elements and trace metals (Pb, Cd, Cr, Co, Ni, Hg, and As) were determined using atomic absorption spectrometer. The concentrations of chromium in chemical fertilizers were higher than the global values.

Positive feedback between increasing atmospheric CO2 and ecosystem productivity

NASA Astrophysics Data System (ADS)

Gelfand, I.; Hamilton, S. K.; Robertson, G. P.

2009-12-01

Increasing atmospheric CO2 will likely affect both the hydrologic cycle and ecosystem productivity. Current assumptions that increasing CO2 will lead to increased ecosystem productivity and plant water use efficiency (WUE) are driving optimistic predictions of higher crop yields as well as greater availability of freshwater resources due to a decrease in evapotranspiration. The plant physiological response that drives these effects is believed to be an increase in carbon uptake either by (a) stronger CO2 gradient between the stomata and the atmosphere, or by (b) reduced CO2 limitation of enzymatic carboxylation within the leaf. The (a) scenario will lead to increased water use efficiency (WUE) in plants. However, evidence for increased WUE is mostly based on modeling studies, and experiments producing a short duration or step-wise increase in CO2 concentration (e.g. free-air CO2 enrichment). We hypothesize that the increase in atmospheric CO2 concentration is having a positive effect on ecosystem productivity and WUE. To investigate this hypothesis, we analyzed meteorological, ANPP, and soil CO2 flux datasets together with carbon isotopic ratio (13C/12C) of archived plant samples from the long term ecological research (LTER) program at Kellogg Biological Station. The datasets were collected between 1989 and 2007 (corresponding to an increase in atmospheric CO2 concentration of ~33 ppmv at Mauna Loa). Wheat (Triticum aestivum) samples taken from 1989 and 2007 show a significant decrease in the C isotope discrimination factor (Δ) over time. Stomatal conductance is directly related to Δ, and thus Δ is inversely related to plant intrinsic WUE (iWUE). Historical changes in the 13C/12C ratio (δ13C) in samples of a perennial forb, Canada goldenrod (Solidago canadensis), taken from adjacent successional fields, indicate changes in Δ upon uptake of CO2 as well. These temporal trends in Δ suggest a positive feedback between the increasing CO2 concentration in the atmosphere, air temperature, and plant iWUE. This positive feedback is expressed by (a) nonparallel changes of δ13C signal of atmospheric CO2 (δa) and plant samples (δp), (b) negative correlation between the Δ and average temperatures during the growth season, although only for temperatures up to 21°C. The lack of effect at higher temperatures suggests a negative influence of growing season warming on the iWUE. These results suggest a complex feedback between atmospheric CO2 increase, plant physiology, ecosystem productivity, and soil CO2 fluxes. These complex effects support our hypothesis of a CO2 fertilization effect on plant productivity, and they raise additional questions regarding adaptation of plants to changing atmospheric CO2 and climate.

Soil microbial metabolic quotient (qCO2) of twelve ecosystems of Mt. Kilimanjaro

NASA Astrophysics Data System (ADS)

Pabst, Holger; Gerschlauer, Friederike; Kiese, Ralf; Kuzyakov, Yakov

2014-05-01

Soil organic carbon, microbial biomass carbon (MBC) and the metabolic quotient qCO2 - as sensitive and important parameters for soil fertility and C turnover - are strongly affected by land-use changes all over the world. These effects are particularly distinct upon conversion of natural to agricultural ecosystems due to very fast carbon (C) and nutrient cycles and high vulnerability, especially in the tropics. In this study, we used an elevational gradient on Mt. Kilimanjaro to investigate the effects of land-use change and elevation on Corg, MBC and qCO2. Down to a soil depth of 18 cm we compared 4 natural (Helichrysum, Erica forest, Podocarpus forest, Ocotea forest), 5 seminatural (disturbed Podocarpus forest, disturbed Ocotea forest, lower montane forest, grassland, savannah), 1 sustainably used (homegarden) and 2 intensively used ecosystems (coffee plantation, maize field) on an elevation gradient from 950 to 3880 m a.s.l.. Using an incubation device, soil CO2-efflux of 18 cm deep soil cores was measured under field moist conditions and mean annual temperature. MBC to Corg ratios varied between 0.7 and 2.3%. qCO2 increased with magnitude of the disturbance, albeit this effect decreased with elevation. Following the annual precipitation of the ecosystems, both, Corg and MBC showed a hum-shaped distribution with elevation, whereas their maxima were between 2500 and 3000 m a.s.l.. Additionaly, Corg and MBC contents were significantly reduced in intensively used agricultural systems. We conclude that the soil microbial biomass and its activity in Mt. Kilimanjaro ecosystems are strongly altered by land-use. This effect is more distinct in lower than in higher elevated ecosystems and strongly dependent on the magnitude of disturbance.

The effect of juvenile hormone on Polistes wasp fertility varies with cooperative behavior.

PubMed

Tibbetts, Elizabeth A; Sheehan, Michael J

2012-04-01

Social insects provide good models for studying how and why the mechanisms that underlie reproduction vary, as there is dramatic reproductive plasticity within and between species. Here, we test how the effect of juvenile hormone (JH) on fertility covaries with cooperative behavior in workers and nest-founding queens in the primitively eusocial wasp Polistes metricus. P. metricus foundresses and workers appear morphologically similar and both are capable of reproduction, though there is variation in the extent of social cooperation and the probability of reproduction across castes. Do the endocrine mechanisms that mediate reproduction co-vary with cooperative behavior? We found dramatic differences in the effect of JH on fertility across castes. In non-cooperative nest-founding queens, all individuals responded to JH by increasing their fertility. However, in cooperative workers, the effect of JH on fertility varies with body weight; large workers increase their fertility in response to JH while small workers do not. The variation in JH response may be an adaptation to facilitate resource allocation based on the probability of independent reproduction. This work contrasts with previous studies in closely related Polistes dominulus paper wasps, in which both foundresses and workers form cooperative associations and both castes show similar, condition-dependent JH response. The variation in JH responsiveness within and between species suggests that endocrine responsiveness and the factors influencing caste differentiation are surprisingly evolutionarily labile. Copyright © 2012 Elsevier Inc. All rights reserved.

Nutrient enrichment shifts mangrove height distribution: Implications for coastal woody encroachment.

PubMed

Weaver, Carolyn A; Armitage, Anna R

2018-01-01

Global changes, such as increased temperatures and elevated CO2, are driving shifts in plant species distribution and dominance, like woody plant encroachment into grasslands. Local factors within these ecotones can influence the rate of regime shifts. Woody encroachment is occurring worldwide, though there has been limited research within coastal systems, where mangrove (woody shrub/tree) stands are expanding into salt marsh areas. Because coastal systems are exposed to various degrees of nutrient input, we investigated how nutrient enrichment may locally impact mangrove stand expansion and salt marsh displacement over time. We fertilized naturally co-occurring Avicennia germinans (black mangrove) and Spartina alterniflora (smooth cordgrass) stands in Port Aransas, TX, an area experiencing mangrove encroachment within the Northern Gulf of Mexico mangrove-marsh ecotone. After four growing seasons (2010-2013) of continuous fertilization, Avicennia was more positively influenced by nutrient enrichment than Spartina. Most notably, fertilized plots had a higher density of taller (> 0.5 m) mangroves and mangrove maximum height was 46% taller than in control plots. Fertilization may promote an increase in mangrove stand expansion within the mangrove-marsh ecotone by shifting Avicennia height distribution. Avicennia individuals, which reach certain species-specific height thresholds, have reduced negative neighbor effects and have higher resilience to freezing temperatures, which may increase mangrove competitive advantage over marsh grass. Therefore, we propose that nutrient enrichment, which augments mangrove height, could act locally as a positive feedback to mangrove encroachment, by reducing mangrove growth suppression factors, thereby accelerating the rates of increased mangrove coverage and subsequent marsh displacement. Areas within the mangrove-marsh ecotone with high anthropogenic nutrient input may be at increased risk of a regime shift from grass to woody dominated ecosystems.

Nutrient enrichment shifts mangrove height distribution: Implications for coastal woody encroachment

PubMed Central

Armitage, Anna R.

2018-01-01

Global changes, such as increased temperatures and elevated CO2, are driving shifts in plant species distribution and dominance, like woody plant encroachment into grasslands. Local factors within these ecotones can influence the rate of regime shifts. Woody encroachment is occurring worldwide, though there has been limited research within coastal systems, where mangrove (woody shrub/tree) stands are expanding into salt marsh areas. Because coastal systems are exposed to various degrees of nutrient input, we investigated how nutrient enrichment may locally impact mangrove stand expansion and salt marsh displacement over time. We fertilized naturally co-occurring Avicennia germinans (black mangrove) and Spartina alterniflora (smooth cordgrass) stands in Port Aransas, TX, an area experiencing mangrove encroachment within the Northern Gulf of Mexico mangrove-marsh ecotone. After four growing seasons (2010–2013) of continuous fertilization, Avicennia was more positively influenced by nutrient enrichment than Spartina. Most notably, fertilized plots had a higher density of taller (> 0.5 m) mangroves and mangrove maximum height was 46% taller than in control plots. Fertilization may promote an increase in mangrove stand expansion within the mangrove-marsh ecotone by shifting Avicennia height distribution. Avicennia individuals, which reach certain species-specific height thresholds, have reduced negative neighbor effects and have higher resilience to freezing temperatures, which may increase mangrove competitive advantage over marsh grass. Therefore, we propose that nutrient enrichment, which augments mangrove height, could act locally as a positive feedback to mangrove encroachment, by reducing mangrove growth suppression factors, thereby accelerating the rates of increased mangrove coverage and subsequent marsh displacement. Areas within the mangrove-marsh ecotone with high anthropogenic nutrient input may be at increased risk of a regime shift from grass to woody dominated ecosystems. PMID:29494657

Effects of different combinations of “Baoshiling” on soil physical and chemical properties of Huangguogan

NASA Astrophysics Data System (ADS)

Xu, Y. H.; Wang, Z. H.; Xiong, B.; Qiu, X.; Liao, L.; Shun, G. C.; Huang, S. J.; Dong, Z. X.; Liu, X. Y.; Xi, L. J.

2017-08-01

The research is done on the Huangguogan (unique citrus breed in Sichuan, China). The experiment setted 27 groups of “Baoshiling” (self-study compound fertilizer) fertilization treatment to explore the “Baoshiling” different combinations on soil physical and chemical properties of Huangguogan. The results showed that all the combinations had improved the soil of Huangguogan orchard. The combination of A3B2C2 had the best effect. The best Fertilization management measures was “Baoshiling” bud flowering fertilizer 2kg, stable fruit fertilizer 2kg, strong fruit fertilizer 2kg. It could reduce the pH of soil and the bulk density of soil, increase the available nitrogen, available phosphorus, available potassium and urease activity.

The next generation of iron fertilization experiments in the Southern Ocean.

PubMed

Smetacek, V; Naqvi, S W A

2008-11-13

Of the various macro-engineering schemes proposed to mitigate global warming, ocean iron fertilization (OIF) is one that could be started at short notice on relevant scales. It is based on the reasoning that adding trace amounts of iron to iron-limited phytoplankton of the Southern Ocean will lead to blooms, mass sinking of organic matter and ultimately sequestration of significant amounts of atmospheric carbon dioxide (CO2) in the deep sea and sediments. This iron hypothesis, proposed by John Martin in 1990 (Martin 1990 Paleoceanography 5, 1-13), has been tested by five mesoscale experiments that provided strong support for its first condition: stimulation of a diatom bloom accompanied by significant CO2 drawdown. Nevertheless, a number of arguments pertaining to the fate of bloom biomass, the ratio of iron added to carbon sequestered and various side effects of fertilization, continue to cast doubt on its efficacy. The idea is also unpopular with the public because it is perceived as meddling with nature. However, this apparent consensus against OIF is premature because none of the published experiments were specifically designed to test its second condition pertaining to the fate of iron-induced organic carbon. Furthermore, the arguments on side effects are based on worst-case scenarios. These doubts, formulated as hypotheses, need to be tested in the next generation of OIF experiments. We argue that such experiments, if carried out at appropriate scales and localities, will not only show whether the technique will work, but will also reveal a wealth of insights on the structure and functioning of pelagic ecosystems in general and the krill-based Southern Ocean ecosystem, in particular. The outcomes of current models on the efficacy and side effects of OIF differ widely, so data from adequately designed experiments are urgently needed for realistic parametrization. OIF is likely to boost zooplankton stocks, including krill, which could have a positive effect on recovery of the great whale populations. Negative effects of possible commercialization of OIF can be controlled by the establishment of an international body headed by scientists to supervise and monitor its implementation.

The effect of carbohydrate accumulation and nitrogen deficiency on feedback regulation of photosynthesis in beech (Fagus sylvatica) under elevated CO2 concentration

NASA Astrophysics Data System (ADS)

Klem, K.; Urban, O.; Holub, P.; Rajsnerova, P.

2012-04-01

One of the main manifestations of global change is an increase in atmospheric CO2 concentration. Elevated concentration of CO2 has stimulating effect on plant photosynthesis and consequently also on the productivity. Long-term studies, however, show that this effect is progressively reduced due to feedback regulation of photosynthesis. The main causes of this phenomenon are considered as two factors: i) increased biomass production consumes a larger amount of nitrogen from the soil and this leads to progressive nitrogen limitation of photosynthesis, particularly at the level of the enzyme Rubisco, ii) the sink capacity is genetically limited and elevated CO2 concentration leads to increased accumulation of carbohydtrates (mainly sucrose, which is the main transport form of assimilates) in leaves. Increased concentrations of carbohydrates leads to a feedback regulation of photosynthesis by both, long-term feedback regulation of synthesis of the enzyme Rubisco, and also due to reduced capacity to produce ATP in the chloroplasts. However, mechanisms for interactive effects of nitrogen and accumulation of non-structural carbohydrates are still not well understood. Using 3-year-old Fagus sylvatica seedlings we have explored the interactive effects of nitrogen nutrition and sink capacity manipulation (sucrose feeding) on the dynamics of accumulation of non-structural carbohydrates and changes in photosynthetic parameters under ambient (385 μmol (CO2) mol-1) and elevated (700 μmol(CO2) mol-1) CO2 concentration. Sink manipulation by sucrose feeding led to a continuous increase of non-structural carbohydrates in leaves, which was higher in nitrogen fertilized seedlings. The accumulation of non-structural carbohydrates was also slightly stimulated by elevated CO2 concentration. Exponential decay (p <0.01) was observed in CO2 assimilation rate and stomatal conductance when the content of non-structural carbohydrates increased. However, this relationship was modified by the nitrogen content. Accumulation of non-structural carbohydrates had relatively smaller effect on actual quantum yield of photosystem II. Both, CO2 assimilation rate and the actual quantum yield of photosystem II decreased more rapidly during sink manipulation in elevated concentrations of CO2 than in ambient. Application of chlorophyll fluorescence imaging enabled us to evaluate changes in spatial distribution of feedback regulation of photosynthesis on the leaf-level. We can conclude that the accumulation of non-structural carbohydrates down-regulates photosynthesis mainly through the stomatal conductance, and this effect is further modified by nitrogen content.

Effects of water hardness on size and hatching success of silver carp eggs

USGS Publications Warehouse

Rach, Jeff J.; Sass, Greg G.; Luoma, James A.; Gaikowski, Mark P.

2010-01-01

Eggs of silver carp Hypophthalmichthys molitrix absorb water after release from the female, causing them to become turgid and to increase substantially in size. The volume of water that diffuses within an egg is most likely determined by (1) the difference in ionic concentration between the egg and the water that surrounds it and (2) the elasticity of the egg membrane. Prior observations suggest that silver carp eggs may swell and burst in soft waters. If water hardness affects silver carp reproductive success in nonnative ecosystems, this abiotic factor could limit silver carp distribution or abundance. In this study, we tested the effect of water hardness on silver carp egg enlargement and hatching success. Groups of newly fertilized silver carp eggs were placed in water at one of five nominal water hardness levels (50, 100, 150, 200, or 250 mg/L as CaCO3) for 1 h to harden (absorb water after fertilization). Egg groups were then placed in separate incubation vessels housed in two recirculation systems that were supplied with either soft (50 mg/L as CaCO3) or hard (250 mg/L as CaCO3) water to evaluate hatching success. Tests were terminated within 24 h after viable eggs had hatched. Eggs that were initially placed in 50-mg/L water to harden were larger (i.e., swelled more) and had a greater probability of hatch than eggs hardened in other water hardness levels. Unlike the effect of water hardness during egg hardening, the water hardness during incubation appeared to have no effect on egg hatching success. Our research suggests that water hardness may not be a limiting factor in the reproduction, recruitment, and range expansion of silver carp in North America.

Improving yield potential in crops under elevated CO(2): Integrating the photosynthetic and nitrogen utilization efficiencies.

PubMed

Kant, Surya; Seneweera, Saman; Rodin, Joakim; Materne, Michael; Burch, David; Rothstein, Steven J; Spangenberg, German

2012-01-01

Increasing crop productivity to meet burgeoning human food demand is challenging under changing environmental conditions. Since industrial revolution atmospheric CO(2) levels have linearly increased. Developing crop varieties with increased utilization of CO(2) for photosynthesis is an urgent requirement to cope with the irreversible rise of atmospheric CO(2) and achieve higher food production. The primary effects of elevated CO(2) levels in most crop plants, particularly C(3) plants, include increased biomass accumulation, although initial stimulation of net photosynthesis rate is only temporal and plants fail to sustain the maximal stimulation, a phenomenon known as photosynthesis acclimation. Despite this acclimation, grain yield is known to marginally increase under elevated CO(2). The yield potential of C(3) crops is limited by their capacity to exploit sufficient carbon. The "C fertilization" through elevated CO(2) levels could potentially be used for substantial yield increase. Rubisco is the rate-limiting enzyme in photosynthesis and its activity is largely affected by atmospheric CO(2) and nitrogen availability. In addition, maintenance of the C/N ratio is pivotal for various growth and development processes in plants governing yield and seed quality. For maximizing the benefits of elevated CO(2), raising plant nitrogen pools will be necessary as part of maintaining an optimal C/N balance. In this review, we discuss potential causes for the stagnation in yield increases under elevated CO(2) levels and explore possibilities to overcome this limitation by improved photosynthetic capacity and enhanced nitrogen use efficiency. Opportunities of engineering nitrogen uptake, assimilatory, and responsive genes are also discussed that could ensure optimal nitrogen allocation toward expanding source and sink tissues. This might avert photosynthetic acclimation partially or completely and drive for improved crop production under elevated CO(2) levels.

Phylogenetic responses of forest trees to global change.

PubMed

Senior, John K; Schweitzer, Jennifer A; O'Reilly-Wapstra, Julianne; Chapman, Samantha K; Steane, Dorothy; Langley, Adam; Bailey, Joseph K

2013-01-01

In a rapidly changing biosphere, approaches to understanding the ecology and evolution of forest species will be critical to predict and mitigate the effects of anthropogenic global change on forest ecosystems. Utilizing 26 forest species in a factorial experiment with two levels each of atmospheric CO2 and soil nitrogen, we examined the hypothesis that phylogeny would influence plant performance in response to elevated CO2 and nitrogen fertilization. We found highly idiosyncratic responses at the species level. However, significant, among-genetic lineage responses were present across a molecularly determined phylogeny, indicating that past evolutionary history may have an important role in the response of whole genetic lineages to future global change. These data imply that some genetic lineages will perform well and that others will not, depending upon the environmental context.

Oyster reproduction is compromised by acidification experienced seasonally in coastal regions.

PubMed

Boulais, Myrina; Chenevert, Kyle John; Demey, Ashley Taylor; Darrow, Elizabeth S; Robison, Madison Raine; Roberts, John Park; Volety, Aswani

2017-10-16

Atmospheric carbon dioxide concentrations have been rising during the past century, leading to ocean acidification (OA). Coastal and estuarine habitats experience annual pH variability that vastly exceeds the magnitude of long-term projections in open ocean regions. Eastern oyster (Crassostrea virginica) reproduction season coincides with periods of low pH occurrence in estuaries, thus we investigated effects of moderate (pH 7.5, pCO 2 2260 µatm) and severe OA (pH 7.1, pCO 2 5584 µatm; and 6.7, pCO 2 18480 µatm) on oyster gametogenesis, fertilization, and early larval development successes. Exposure at severe OA during gametogenesis caused disruption in oyster reproduction. Oogenesis appeared to be more sensitive compared to spermatogenesis. However, Eastern oyster reproduction was resilient to moderate OA projected for the near-future. In the context of projected climate change exacerbating seasonal acidification, OA of coastal habitats could represent a significant bottleneck for oyster reproduction which may have profound negative implications for coastal ecosystems reliant on this keystone species.

Climate Change Mitigation through Enhanced Weathering in Bioenergy Crops

NASA Astrophysics Data System (ADS)

Kantola, I. B.; Masters, M. D.; Wolz, K. J.; DeLucia, E. H.

2016-12-01

Bioenergy crops are a renewable alternative to fossil fuels that reduce the net flux of CO2 to the atmosphere through carbon sequestration in plant tissues and soil. A portion of the remaining atmospheric CO2 is naturally mitigated by the chemical weathering of silica minerals, which sequester carbon as carbonates. The process of mineral weathering can be enhanced by crushing the minerals to increase surface area and applying them to agricultural soils, where warm temperatures, moisture, and plant roots and root exudates accelerate the weathering process. The carbonate byproducts of enhanced weathering are expected accumulate in soil water and reduce soil acidity, reduce nitrogen loss as N2O, and increase availability of certain soil nutrients. To determine the potential of enhanced weathering to alter the greenhouse gas balance in both annual (high disturbance, high fertilizer) and perennial (low disturbance, low fertilizer) bioenergy crops, finely ground basalt was applied to fields of maize, soybeans, and miscanthus at the University of Illinois Energy Farm. All plots showed an immediate soil temperature response at 10 cm depth, with increases of 1- 4 °C at midday. Early season CO2 and N2O fluxes mirrored soil temperature prior to canopy closure in all crops, while total N2O fluxes from miscanthus were lower than corn and soybeans in both basalt treatment and control plots. Mid-season N2O production was reduced in basalt-treated corn compared to controls. Given the increasing footprint of bioenergy crops, the ability to reduce GHG emissions in basalt-treated fields has the potential to mitigate atmospheric warming while benefitting soil fertility with the byproducts of weathering.

Scenario analysis of fertilizer management practices for N2O mitigation from corn systems in Canada.

PubMed

Abalos, Diego; Smith, Ward N; Grant, Brian B; Drury, Craig F; MacKell, Sarah; Wagner-Riddle, Claudia

2016-12-15

Effective management of nitrogen (N) fertilizer application by farmers provides great potential for reducing emissions of the potent greenhouse gas nitrous oxide (N 2 O). However, such potential is rarely achieved because our understanding of what practices (or combination of practices) lead to N 2 O reductions without compromising crop yields remains far from complete. Using scenario analysis with the process-based model DNDC, this study explored the effects of nine fertilizer practices on N 2 O emissions and crop yields from two corn production systems in Canada. The scenarios differed in: timing of fertilizer application, fertilizer rate, number of applications, fertilizer type, method of application and use of nitrification/urease inhibitors. Statistical analysis showed that during the initial calibration and validation stages the simulated results had no significant total error or bias compared to measured values, yet grain yield estimations warrant further model improvement. Sidedress fertilizer applications reduced yield-scaled N 2 O emissions by c. 60% compared to fall fertilization. Nitrification inhibitors further reduced yield-scaled N 2 O emissions by c. 10%; urease inhibitors had no effect on either N 2 O emissions or crop productivity. The combined adoption of split fertilizer application with inhibitors at a rate 10% lower than the conventional application rate (i.e. 150kgNha -1 ) was successful, but the benefits were lower than those achieved with single fertilization at sidedress. Our study provides a comprehensive assessment of fertilizer management practices that enables policy development regarding N 2 O mitigation from agricultural soils in Canada. Copyright © 2016 Elsevier B.V. All rights reserved.

Mitigation of greenhouse gas emission on abandoned peatlands by growing reed canary grass

NASA Astrophysics Data System (ADS)

Järveoja, J.; Laht, J.; Soosaar, K.; Maddison, M.; Ostonen, I.; Mander, Ü.

2012-04-01

We used combined closed-chamber and plant biomass techniques to study the impact of reed canary grass (RCG, Phalaris arundinacea) cultivation on greenhouse gas (GHG) fluxes and carbon balance of an abandoned peat extraction area in Lavassaare, Estonia (N58°34'20''; E24°23'15''). Three core study sites were chosen within the abandoned peat extraction area: (I) bare peat soil (abandoned and not planted site), (II) non-fertilized Phalaris site, (III) and fertilized Phalaris site (all on drained Fibric Histosols). In addition, (IV) the natural raised bog (Fibric Histosol) and (V) the cultivated fen meadow (drained Sapric Histosol) served as reference sites. The CO2, CH4 and N2O fluxes were determined using the closed-chamber method once a month from May 2010 to December 2011. White 60 L chambers made of PVC and sealed with a water-filled ring on the soil surface were installed in 5 replicates on each site. The gas was sampled 3 times per hour in 100 mL pre-evacuated glass bottles, and in the lab the gas concentrations were measured using the Shimadzu GC-2014 (ECD, FID) gas-chromatographic system combined with a Loftfield autosampler. Measurements of groundwater level and soil temperature (10, 20, 30, and 40 cm depths) were performed simultaneously. Biomass assessments of RCG were carried out just after maximal growth of macrophytes, in early September 2010, in April 2011 just after snow melt (time of minimum aboveground biomass), and again in September 2011. Aboveground biomass samples were collected from 1×1m plots. Belowground biomass samples were collected at a depth of 25 cm in 3 replicates adjacent to each chamber using a 10×10 cm auger. Samples were analyzed for N, P and C. Our results showed high nitrous oxide emissions (up to 541 μg N2O-N m-2 h-1) from the fen meadow and high methane emissions from the natural raised bog (up to 12915 μg CH4-C m-2 h-1). The low CH4 emission from the Phalaris plots and bare soil was due to the deeper water table (up to 85 cm below ground) and high sulfur concentration in peat (up to 23 g kg-1), which probably inhibited methanogenesis. The high CO2 emission on fertilized and non-fertilized Phalaris plots in comparison to the bare peat site was probably caused by: (1) the higher plant biomass: more dissolved C coming from roots and greater amount of fine root turnover, (2) the influence of fresh plant litter on the peat mineralization on Phalaris plots, and (3) inhibited mineralization by recalcitrant C of bare peat. Our results demonstrated that as a total, the Phalaris sites acted as net carbon sinks, sequestering C in the amount of 6929.5 and 6083.5 kg CO2-C ha-1 yr-1 on the fertilized and non-fertilized plots, respectively, whereas the bare peat site acted as a carbon source (emitting 687.5 kg CO2-C ha-1 yr-1).

Nanosiderite is effective to alleviate iron chlorosis in sensitive plants growing on calcareous soils

NASA Astrophysics Data System (ADS)

Sánchez-Alcalá, I.; del Campillo, M. C.; Barrón, V.; Torrent, J.

2012-04-01

Key words: siderite, iron chlorosis, calcareous soil, goethite, lepidocrocite Nanosized siderite (FeCO3) prepared by mixing FeSO4 and K2CO3 solutions [either alone or in presence of phosphate (siderites SID and SIDP, respectively)] was used in our experiments. The products of oxidation of siderite in a calcite suspension were goethite or a mixture of goethite and lepidocrocite when phosphate was present. These iron oxides were nanosized and acid NH4oxalate-soluble, which suggested they could be a good source of iron (Fe) for plants sensitive to Fe deficiency yellowing (chlorosis). To evaluate the effectiveness and long-term effects of suspensions of siderite mixed with calcareous soil to prevent Fe chlorosis, a pot growth experiment was carried out with five consecutive crops: chickpea (twice), peanut (twice) and strawberry. Suspensions of siderites (SID and SIDP) were mixed with 220 g of soil at the beginning of the experiment at rates of 0.24, 0.46, 0.93 and 1.40 g siderite (0.12, 0.22, 0.45, and 0.67 g Fe) kg-1 soil. A control (no Fe added) and a positive control (Fe-chelate as FeEDDHA before each cropping) were included. The concentration of chlorophyll in the youngest leaves was estimated three times for chickpea and peanut, and five times for strawberry via the SPAD value (SPAD 502 portable chlorophyll meter). The SPAD for the control plants was lower than that for Fe-fertilized plants. For all crops, times and siderite types, SPAD tended to systematically increase with increasing siderite dose, and SID and SIDP had similar effectiveness. At harvest, the SPAD for the plants fertilized with the highest siderite dose (1.40 g kg-1) did not differ significantly from that for FeEDDHA-fertilized plants. Our results suggest in summary that siderite is effective in preventing iron chlorosis and has a long-lasting effect, as the likely result of the high specific surface and high solubility of the crystalline Fe oxides resulting from its oxidation. Futhermore, siderite is readily prepared in the field, not easily leached from the soil and environmentally safe, thus constituting a good Fe fertilizer. Acknowledgments: This work was funded by the Spain's Ministerio de Ciencia e Innovación and the European Regional Development Fund (Projects AGL 2005-06691-C02-01 and AGL 2008-05053-C02-02).

Earth system model simulations show different feedback strengths of the terrestrial carbon cycle under glacial and interglacial conditions

NASA Astrophysics Data System (ADS)

Adloff, Markus; Reick, Christian H.; Claussen, Martin

2018-04-01

In simulations with the MPI Earth System Model, we study the feedback between the terrestrial carbon cycle and atmospheric CO2 concentrations under ice age and interglacial conditions. We find different sensitivities of terrestrial carbon storage to rising CO2 concentrations in the two settings. This result is obtained by comparing the transient response of the terrestrial carbon cycle to a fast and strong atmospheric CO2 concentration increase (roughly 900 ppm) in Coupled Climate Carbon Cycle Model Intercomparison Project (C4MIP)-type simulations starting from climates representing the Last Glacial Maximum (LGM) and pre-industrial times (PI). In this set-up we disentangle terrestrial contributions to the feedback from the carbon-concentration effect, acting biogeochemically via enhanced photosynthetic productivity when CO2 concentrations increase, and the carbon-climate effect, which affects the carbon cycle via greenhouse warming. We find that the carbon-concentration effect is larger under LGM than PI conditions because photosynthetic productivity is more sensitive when starting from the lower, glacial CO2 concentration and CO2 fertilization saturates later. This leads to a larger productivity increase in the LGM experiment. Concerning the carbon-climate effect, it is the PI experiment in which land carbon responds more sensitively to the warming under rising CO2 because at the already initially higher temperatures, tropical plant productivity deteriorates more strongly and extratropical carbon is respired more effectively. Consequently, land carbon losses increase faster in the PI than in the LGM case. Separating the carbon-climate and carbon-concentration effects, we find that they are almost additive for our model set-up; i.e. their synergy is small in the global sum of carbon changes. Together, the two effects result in an overall strength of the terrestrial carbon cycle feedback that is almost twice as large in the LGM experiment as in the PI experiment. For PI, ocean and land contributions to the total feedback are of similar size, while in the LGM case the terrestrial feedback is dominant.

Measuring priming using 14C of respired CO2: effects on respiration source pools and interactions with warming

NASA Astrophysics Data System (ADS)

Hopkins, F. M.; Trumbore, S.

2011-12-01

The role of substrate availability on soil carbon turnover is a critical unknown in predicting future soil carbon stocks. Substrate composition and availability can be altered by land cover change, warming, and nitrogen deposition, which can in turn affect soil carbon stocks through the priming effect. In particular, little is understood about the interaction between warming and changing substrate concentration. We examined the interactions between global change factors and the priming effect using sucrose addition to incubations of soils from two forest Free Air CO2 Enrichment (FACE) sites (Duke and Aspen). In addition to the in situ global change manipulations conducted at these sites, the CO2 fertilization procedure over the decade-long experiment labeled soil carbon pools with fossil-derived carbon (depleted in 14C relative to the background isotope content of soil carbon), allowing us to determine the effect of priming on respiration of soil carbon substrates of different ages. Thus, we used the carbon-13 signature of sucrose-derived CO2 to account for losses of substrate C, and the carbon-14 signature to partition fluxes of soil-derived CO2 between pre-FACE (> 10 y) and FACE derived (< 10 y) carbon sources. At both sites, we observed a positive priming effect-an increase in the rate of soil carbon derived respiration due to sucrose addition. However, the effect of substrate addition on respiratory source pools, as measured by 14C of respiration, varied greatly. At Duke FACE, we observed an increase in 14C content of CO2 of primed soil carbon, whereas at Aspen, we observed no difference. The amount of CO2 released by priming increased with temperature, but was proportionally similar to the amount of increase in basal respiration rates (no differences in Q10). At Duke, both warming and priming served to increase the 14C of respiration, whereas only warming changed 14C of respiration at Aspen. Despite similar overall carbon stocks, differences in the source of the priming effect between the two sites may be due to inherent differences in the relative role of stabilization factors within the soil carbon stock.

A review of national and international activities on modeling the effects of increased CO/sub 2/ concentrations on the simulation of regional crop production: (A report on linkage between climate and crop models): Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Decker, W.L.; Achutuni, R.

1987-01-01

General circulation models have been used to estimate the probable changes in climate due to increased levels of carbon dioxide. These models, generally, project increases in the mean surface temperatures; but changes in precipitation due to CO/sub 2/ enrichment are not as clear. It appears that some process models, which utilize a minimum amount of empiricism, can be adopted for use in studying the impacts of both climate change scenarios and the direct effects of CO/sub 2/ fertilization. The CERES-Maize, CERES-Wheat, SORGF, GLYCIM, and SOYGRO are among those classified for this use. There is a great deal of effort beingmore » directed toward these developments. A WMO/UNEP/ICSU focus has sponsored at least two European meetings but with only limited success for testing production models. A similar effort has been conducted by the Commission of European Communities. An attempt has been made to modify the CERES models, which have been used in climate studies, for use in simulation of the direct effects. Initial simulations involving this modification, show that doubling CO/sub 2/ will increase corn production 12 to 30% at locations in northern Illinois for the four-year period 1982 to 1985. The increase in yield due to higher photosynthesis showed a greater effect than the impact of decreased transpiration.« less

Growth but Not Photosynthesis Response of a Host Plant to Infection by a Holoparasitic Plant Depends on Nitrogen Supply

PubMed Central

Shen, Hao; Xu, Shu-Jun; Hong, Lan; Wang, Zhang-Ming; Ye, Wan-Hui

2013-01-01

Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the growth and photosynthesis responses of the host plant Mikania micrantha to infection by the holoparasite Cuscuta campestris by focusing on the interaction of nitrogen and infection. Mikania micrantha plants fertilized at 0.2, 1 and 5 mM nitrate were grown with and without C. campestris infection. We observed that the infection significantly reduced M. micrantha growth at each nitrate fertilization and more severely at low than at high nitrate. Such alleviation at high nitrate was largely attributed to a stronger influence of infection on root biomass at low than at high nitrate fertilization. However, although C. campestris altered allometry and inhibited host photosynthesis, the magnitude of the effects was independent of nitrate fertilizations. The infection reduced light saturation point, net photosynthesis at saturating irradiances, apparent quantum yield, CO2 saturated rate of photosynthesis, carboxylation efficiency, the maximum carboxylation rate of Rubisco, and maximum light-saturated rate of electron transport, and increased light compensation point in host leaves similarly across nitrate levels, corresponding to a similar magnitude of negative effects of the parasite on host leaf soluble protein and Rubisco concentrations, photosynthetic nitrogen use efficiency and stomatal conductance across nitrate concentrations. Thus, the more severe inhibition in host growth at low than at high nitrate supplies cannot be attributed to a greater parasite-induced reduction in host photosynthesis, but the result of a higher proportion of host resources transferred to the parasite at low than at high nitrate levels. PMID:24116055

By their words ye shall know them: Evidence of genetic selection against general intelligence and concurrent environmental enrichment in vocabulary usage since the mid 19th century

PubMed Central

Menie, Michael A. Woodley of; Fernandes, Heitor B. F.; José Figueredo, Aurelio; Meisenberg, Gerhard

2015-01-01

It has been theorized that declines in general intelligence (g) due to genetic selection stemming from the inverse association between completed fertility and IQ and the Flynn effect co-occur, with the effects of the latter being concentrated on less heritable non-g sources of intelligence variance. Evidence for this comes from the observation that 19th century populations were more intellectually productive, and also exhibited faster simple reaction times than modern ones, suggesting greater information-processing ability and therefore higher g. This co-occurrence model is tested via examination of historical changes in the utilization frequencies of words from the highly g-loaded WORDSUM test across 5.9 million texts spanning the period 1850–2005. Consistent with predictions, words with higher difficulties (δ parameters from Item Response Theory) and stronger negative correlations between pass rates and completed fertility declined in use over time whereas less difficult and less strongly selected words, increased in use over time, consistent with a Flynn effect stemming in part from the vocabulary enriching effects of increases in population literacy. These findings persisted when explicitly controlled for word age, changing literacy rates and temporal autocorrelation. These trends constitute compelling evidence for the co-occurrence model. PMID:25954211

Effects of ocean acidification on calcification of symbiont-bearing reef foraminifers

NASA Astrophysics Data System (ADS)

Fujita, K.; Hikami, M.; Suzuki, A.; Kuroyanagi, A.; Sakai, K.; Kawahata, H.; Nojiri, Y.

2011-08-01

Ocean acidification (decreases in carbonate ion concentration and pH) in response to rising atmospheric pCO2 is generally expected to reduce rates of calcification by reef calcifying organisms, with potentially severe implications for coral reef ecosystems. Large, algal symbiont-bearing benthic foraminifers, which are important primary and carbonate producers in coral reefs, produce high-Mg calcite shells, whose solubility can exceed that of aragonite produced by corals, making them the "first responder" in coral reefs to the decreasing carbonate saturation state of seawater. Here we report results of culture experiments performed to assess the effects of ongoing ocean acidification on the calcification of symbiont-bearing reef foraminifers using a high-precision pCO2 control system. Living clone individuals of three foraminiferal species (Baculogypsina sphaerulata, Calcarina gaudichaudii, and Amphisorus hemprichii) were subjected to seawater at five pCO2 levels from 260 to 970 μatm. Cultured individuals were maintained for about 12 weeks in an indoor flow-through system under constant water temperature, light intensity, and photoperiod. After the experiments, the shell diameter and weight of each cultured specimen were measured. Net calcification of B. sphaerulata and C. gaudichaudii, which secrete a hyaline shell and host diatom symbionts, increased under intermediate levels of pCO2 (580 and/or 770 μatm) and decreased at a higher pCO2 level (970 μatm). Net calcification of A. hemprichii, which secretes a porcelaneous shell and hosts dinoflagellate symbionts, tended to decrease at elevated pCO2. Observed different responses between hyaline and porcelaneous species are possibly caused by the relative importance of elevated pCO2, which induces CO2 fertilization effects by algal symbionts, versus associated changes in seawater carbonate chemistry, which decreases a carbonate concentration. Our findings suggest that ongoing ocean acidification might favor symbiont-bearing reef foraminifers with hyaline shells at intermediate pCO2 levels (580 to 770 μatm) but be unfavorable to those with either hyaline or porcelaneous shells at higher pCO2 levels (near 1000 μatm).

Generation of rats from vitrified oocytes with surrounding cumulus cells via in vitro fertilization with cryopreserved sperm.

PubMed

Fujiwara, Katsuyoshi; Kamoshita, Maki; Kato, Tsubasa; Ito, Junya; Kashiwazaki, Naomi

2017-01-01

The objective of this study was to evaluate fertility and full-term development of rat vitrified oocytes after in vitro fertilization (IVF) with cryopreserved sperm. Oocytes with or without surrounding cumulus cells were vitrified with 30% ethylene glycol + 0.5 mol/L sucrose + 20% fetal calf serum by using the Cryotop method. The warmed oocytes were co-cultured with sperm. Although the denuded/vitrified oocytes were not fertilized, some of the oocytes vitrified with cumulus cells were fertilized (32.7%) after IVF with fresh sperm. When IVF was performed with cryopreserved sperm, vitrified or fresh oocytes with cumulus cells were fertilized (62.9% or 41.1%, respectively). In addition, to confirm the full-term development of the vitrified oocytes with surrounding cumulus cells after IVF with cryopreserved sperm, 108 vitrified oocytes with two pronuclei (2PN) were transferred into eight pseudopregnant females, and eight pups were obtained from three recipients. The present work demonstrates that vitrified rat oocytes surrounded by cumulus cells can be fertilized in vitro with cryopreserved sperm, and that 2PN embryos derived from cryopreserved gametes can develop to term. To our knowledge, this is the first report of successful generation of rat offspring derived from vitrified oocytes that were fertilized in vitro with cryopreserved sperm. © 2016 Japanese Society of Animal Science.

Forecasting carbon budget under climate change and CO2 fertilization for subtropical region in China using integrated biosphere simulator (IBIS) model

USGS Publications Warehouse

Zhu, Q.; Jiang, H.; Liu, J.; Peng, C.; Fang, X.; Yu, S.; Zhou, G.; Wei, X.; Ju, W.

2011-01-01

The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr-1 during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr-1. NEP will increase to about 5 Mt C yr-1 by the end of the 21st century with the increasing atmospheric CO2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang's forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration will have little contribution to vegetation changes. Simulated NPP shows geographic patterns consistent with temperature to a certain extent, and precipitation is not the limiting factor for forest NPP in the subtropical climate conditions. There is no close relationship between the spatial pattern of NEP and climate condition.

Forecasting carbon budget under climate change and CO 2 fertilization for subtropical region in China using integrated biosphere simulator (IBIS) model

USGS Publications Warehouse

Zhu, Q.; Jiang, H.; Liu, J.; Peng, C.; Fang, X.; Yu, S.; Zhou, G.; Wei, X.; Ju, W.

2011-01-01

The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO 2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO 2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km 2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr -1 during the last half of the 21 st century. An NPP increase of about 24 Mt C by the end of the 21 st century was estimated with the combined effects of increasing CO 2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr -1. NEP will increase to about 5 Mt C yr -1 by the end of the 21 st century with the increasing atmospheric CO 2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang's forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO 2 concentration will have little contribution to vegetation changes. Simulated NPP shows geographic patterns consistent with temperature to a certain extent, and precipitation is not the limiting factor for forest NPP in the subtropical climate conditions. There is no close relationship between the spatial pattern of NEP and climate condition.

Effect of Biochar on Greenhouse Gas Emissions and Nitrogen Cycling in Laboratory and Field Experiments

NASA Astrophysics Data System (ADS)

Hagemann, Nikolas; Harter, Johannes; Kaldamukova, Radina; Ruser, Reiner; Graeff-Hönninger, Simone; Kappler, Andreas; Behrens, Sebastian

2014-05-01

The extensive use of nitrogen (N) fertilizers in agriculture is a major source of anthropogenic N2O emissions contributing 8% to global greenhouse gas emissions. Soil biochar amendment has been suggested as a means to reduce both CO2 and non-CO2 greenhouse gas emissions. The reduction of N2O emissions by biochar has been demonstrated repeatedly in field and laboratory experiments. However, the mechanisms of the reduction remain unclear. Further it is not known how biochar field-weathering affects GHG emissions and how agro-chemicals, such as the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), that is often simultaneously applied together with commercial N-fertilizers, impact nitrogen transformation and N2O emissions from biochar amended soils. In order investigate the duration of the biochar effect on soil N2O emissions and its susceptibility to DMPP application we performed a microcosm and field study with a high-temperature (400 ° C) beech wood derived biochar (60 t ha-1 and 5 % (w/w) biochar in the field and microcosms, respectively). While the field site contained the biochar already for three years, soil and biochar were freshly mixed for the laboratory microcosm experiments. In both studies we quantified GHG emissions and soil nitrogen speciation (nitrate, nitrite, ammonium). While the field study was carried out over the whole vegetation period of the sunflower Helianthus annuus L., soil microcosm experiments were performed for up to 9 days at 28° C. In both experiments a N-fertilizer containing DMPP was applied either before planting of the sunflowers or at the beginning of soil microcosms incubation. Laboratory microcosm experiments were performed at 60% water filled pore space reflecting average field conditions. Our results show that biochar effectively reduced soil N2O emissions by up to 60 % in the field and in the soil microcosm experiments. No significant differences in N2O emission mitigation potential between field-aged and fresh biochar were observed for the specific biochar used in this study. N2O emission reduction occurred even in the presence of DMPP in the field and in the laboratory microcosms. Our results suggest that simultaneous measurements of soil samples from the same field site in the laboratory yield similar biochar effects to those quantified in the field and that the mechanisms of N2O mitigation seem to be independent of plant growth and application of the commercial nitrification inhibitor DMPP.

Solidus of carbonated fertile peridotite under fluid-saturated conditions

NASA Astrophysics Data System (ADS)

Falloon, Trevor J.; Green, David H.

1990-03-01

The solidus for a fertile peridotite composition ("Hawaiian pyrolite") in the presence of a CO2-H2O fluid phase has been determined from 10 to 35 kbar. The intersection of the decarbonation reaction (olivine + diopside + CO2 ←→ orthopyroxene + dolomite) with the pyrolite solidus defines the point Q‧, located at 22 kbar and 940 °C. At pressures less than Q‧, the solidus passes through a temperature maximum at 14 kbar, 1060 °C. The solidus is coincident with amphibole breakdown at pressures less than 16 kbar. At pressures above Q‧, the solidus is defined by the dissolution of crystalline carbonate into a sodic, dolomitic carbonatite melt. The solidus is at a temperature of 925 °C at ˜28 kbar. The solidus temperature above the point Q‧ is similar to the solidus determined for Hawaiian pyrolite-H2O-CO2 for small contents of H2O (<0.3 wt%) and CO2 (<5 wt%), thus indicating that the primary sodic dolomitic carbonatite melt at both solidi has a very low and limited H2O solubility. The new data clarify the roles of carbonatite melt, carbonated silicate melt, and H2O-rich fluid in mantle conditions that are relatively oxidized (fO2 ˜ MW to FMQ). In particular, a carbonatite melt + garnet lherzolite region is intersected by continental shield geothermal gradients, but such geotherms only intersect regions with carbonated silicate melt if perturbed to higher temperatures ("kinked geotherm").

Hepatitis B Virus S Protein Enhances Sperm Apoptosis and Reduces Sperm Fertilizing Capacity In Vitro

PubMed Central

Huang, JiHua; Zhong, Ying; Fang, XiaoWu; Xie, QingDong; Kang, XiangJin; Wu, RiRan; Li, FangZheng; Xu, XiaoQin; Lu, Hui; Xu, Lan; Huang, TianHua

2013-01-01

Objective Studying the impact of Hepatitis B virus S protein (HBs) on early apoptotic events in human spermatozoa and sperm fertilizing capacity. Methodology/Principal Findings Spermatozoa were exposed to HBs (0, 25, 50, 100 µg/ml) for 3 h, and then fluo-4 AM calcium assay, Calcein/Co2+ assay, protein extraction and ELISA, ADP/ATP ratio assay, sperm motility and hyperactivation and sperm-zona pellucida (ZP) binding and ZP-induced acrosome reaction (ZPIAR) tests were performed. The results showed that in the spermatozoa, with increasing concentration of HBs, (1) average cytosolic free Ca2+ concentration ([Ca2+]i) rose; (2) fluorescence intensity of Cal-AM declined; (3) average levels of cytochrome c decreased in mitochondrial fraction and increased in cytosolic fraction; (4) ADP/ATP ratios rose; (5) average rates of total motility and mean hyperactivation declined; (6) average rate of ZPIAR declined. In the above groups the effects of HBs exhibited dose dependency. However, there was no significant difference in the number of sperms bound to ZP between the control and all test groups. Conclusion HBs could induce early events in the apoptotic cascade in human spermatozoa, such as elevation of [Ca2+]i, opening of mitochondrial permeability transition pore (MPTP), release of cytochrome c (cyt c) and increase of ADP/ATP ratio, but exerted a negative impact on sperm fertilizing capacity. PMID:23874723

Effect of nitrogen, phosphorous, and their interaction on coral reef algal succession in Glover's Reef, Belize.

PubMed

McClanahan, T R; Carreiro-Silva, M; DiLorenzo, M

2007-12-01

Nitrogen and phosphorous fertilizers were used to determine their short-term summer effects on algal colonization, abundance, and species composition in moderate herbivory treatments. Secondary succession of algae on coral skeletons was examined in four treatments: an untreated control, a pure phosphate fertilizer, a pure nitrogen fertilizer, and an equal mix of the two fertilizers. Turf algae cover was the only measure of algae abundance to respond significantly to fertilization. Turf cover was three times higher in treatments with added nitrogen when compared with the pure phosphorus treatment. These turfs were dominated by green and cyanobacteria taxa, namely Enteromorpha prolifera, Lyngbya confervoides, and two species of Cladophora. The phosphate treatment was dominated by encrusting corallines and the cyanobacteria L. confervoides, while the controls had the highest cover of frondose brown algae, namely Padina sanctae-crucis and two species of Dictyota. Results indicate that turf algae were co-limited by nitrogen and phosphorus but enrichment appeared to inhibit brown frondose algae that currently dominate these reefs. Number of species was lowest on the pure phosphorus and nitrogen treatments, highest in the controls and intermediate in the mixed treatments, which suggests that diversity is reduced most by an imbalanced nutrient ratio.

Role of CO2, climate and land use in regulating the seasonal amplitude increase of carbon fluxes in terrestrial ecosystems: a multimodel analysis

NASA Astrophysics Data System (ADS)

Zhao, Fang; Zeng, Ning; Asrar, Ghassem; Friedlingstein, Pierre; Ito, Akihiko; Jain, Atul; Kalnay, Eugenia; Kato, Etsushi; Koven, Charles D.; Poulter, Ben; Rafique, Rashid; Sitch, Stephen; Shu, Shijie; Stocker, Beni; Viovy, Nicolas; Wiltshire, Andy; Zaehle, Sonke

2016-09-01

We examined the net terrestrial carbon flux to the atmosphere (FTA) simulated by nine models from the TRENDY dynamic global vegetation model project for its seasonal cycle and amplitude trend during 1961-2012. While some models exhibit similar phase and amplitude compared to atmospheric inversions, with spring drawdown and autumn rebound, others tend to rebound early in summer. The model ensemble mean underestimates the magnitude of the seasonal cycle by 40 % compared to atmospheric inversions. Global FTA amplitude increase (19 ± 8 %) and its decadal variability from the model ensemble are generally consistent with constraints from surface atmosphere observations. However, models disagree on attribution of this long-term amplitude increase, with factorial experiments attributing 83 ± 56 %, -3 ± 74 and 20 ± 30 % to rising CO2, climate change and land use/cover change, respectively. Seven out of the nine models suggest that CO2 fertilization is the strongest control - with the notable exception of VEGAS, which attributes approximately equally to the three factors. Generally, all models display an enhanced seasonality over the boreal region in response to high-latitude warming, but a negative climate contribution from part of the Northern Hemisphere temperate region, and the net result is a divergence over climate change effect. Six of the nine models show that land use/cover change amplifies the seasonal cycle of global FTA: some are due to forest regrowth, while others are caused by crop expansion or agricultural intensification, as revealed by their divergent spatial patterns. We also discovered a moderate cross-model correlation between FTA amplitude increase and increase in land carbon sink (R2 = 0.61). Our results suggest that models can show similar results in some benchmarks with different underlying mechanisms; therefore, the spatial traits of CO2 fertilization, climate change and land use/cover changes are crucial in determining the right mechanisms in seasonal carbon cycle change as well as mean sink change.

Implications of overestimated anthropogenic CO2 emissions on East Asian and global land CO2 flux inversion

NASA Astrophysics Data System (ADS)

Saeki, Tazu; Patra, Prabir K.

2017-12-01

Measurement and modelling of regional or country-level carbon dioxide (CO2) fluxes are becoming critical for verification of the greenhouse gases emission control. One of the commonly adopted approaches is inverse modelling, where CO2 fluxes (emission: positive flux, sink: negative flux) from the terrestrial ecosystems are estimated by combining atmospheric CO2 measurements with atmospheric transport models. The inverse models assume anthropogenic emissions are known, and thus the uncertainties in the emissions introduce systematic bias in estimation of the terrestrial (residual) fluxes by inverse modelling. Here we show that the CO2 sink increase, estimated by the inverse model, over East Asia (China, Japan, Korea and Mongolia), by about 0.26 PgC year-1 (1 Pg = 1012 g) during 2001-2010, is likely to be an artifact of the anthropogenic CO2 emissions increasing too quickly in China by 1.41 PgC year-1. Independent results from methane (CH4) inversion suggested about 41% lower rate of East Asian CH4 emission increase during 2002-2012. We apply a scaling factor of 0.59, based on CH4 inversion, to the rate of anthropogenic CO2 emission increase since the anthropogenic emissions of both CO2 and CH4 increase linearly in the emission inventory. We find no systematic increase in land CO2 uptake over East Asia during 1993-2010 or 2000-2009 when scaled anthropogenic CO2 emissions are used, and that there is a need of higher emission increase rate for 2010-2012 compared to those calculated by the inventory methods. High bias in anthropogenic CO2 emissions leads to stronger land sinks in global land-ocean flux partitioning in our inverse model. The corrected anthropogenic CO2 emissions also produce measurable reductions in the rate of global land CO2 sink increase post-2002, leading to a better agreement with the terrestrial biospheric model simulations that include CO2-fertilization and climate effects.

Assessing the effect of elevated carbon dioxide on soil carbon: a comparison of four meta-analyses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hungate, B. A.; van Groenigen, K.; Six, J.

2009-08-01

Soil is the largest reservoir of organic carbon (C) in the terrestrial biosphere and soil C has a relatively long mean residence time. Rising atmospheric carbon dioxide (CO{sub 2}) concentrations generally increase plant growth and C input to soil, suggesting that soil might help mitigate atmospheric CO{sub 2} rise and global warming. But to what extent mitigation will occur is unclear. The large size of the soil C pool not only makes it a potential buffer against rising atmospheric CO{sub 2}, but also makes it difficult to measure changes amid the existing background. Meta-analysis is one tool that can overcomemore » the limited power of single studies. Four recent meta-analyses addressed this issue but reached somewhat different conclusions about the effect of elevated CO{sub 2} on soil C accumulation, especially regarding the role of nitrogen (N) inputs. Here, we assess the extent of differences between these conclusions and propose a new analysis of the data. The four meta-analyses included different studies, derived different effect size estimates from common studies, used different weighting functions and metrics of effect size, and used different approaches to address nonindependence of effect sizes. Although all factors influenced the mean effect size estimates and subsequent inferences, the approach to independence had the largest influence. We recommend that meta-analysts critically assess and report choices about effect size metrics and weighting functions, and criteria for study selection and independence. Such decisions need to be justified carefully because they affect the basis for inference. Our new analysis, with a combined data set, confirms that the effect of elevated CO{sub 2} on net soil C accumulation increases with the addition of N fertilizers. Although the effect at low N inputs was not significant, statistical power to detect biogeochemically important effect sizes at low N is limited, even with meta-analysis, suggesting the continued need for long-term experiments.« less

Parameters of microbial respiration in soils of the impact zone of a mineral fertilizer factory

NASA Astrophysics Data System (ADS)

Zhukova, A. D.; Khomyakov, D. M.

2015-08-01

The carbon content in the microbial biomass and the microbial production of CO2 (the biological component of soil respiration) were determined in the upper layer (0-10 cm) of soils in the impact zone of the OJSC Voskresensk Mineral Fertilizers, one of the largest factories manufacturing mineral fertilizers in Russia. Statistical characteristics and schematic distribution of the biological parameters in the soil cover of the impact zone were analyzed. The degree of disturbance of microbial communities in the studied objects varied from weak to medium. The maximum value (0.44) was observed on the sampling plot 4 km away from the factory and 0.5 km away from the place of waste (phosphogypsum) storage. Significantly lower carbon content in the microbial biomass and its specific respiration were recorded in the agrosoddy-podzolic soil as compared with the alluvial soil sampled at the same distance from the plant. The effects of potential soil pollutants (fluorine, sulfur, cadmium, and stable strontium) on the characteristics of soil microbial communities were described with reliable regression equations.

Carbon balance of a fertile forestry-drained peatland in southern Finland

NASA Astrophysics Data System (ADS)

Lohila, Annalea; Korkiakoski, Mika; Tuovinen, Juha-Pekka; Minkkinen, Kari; Penttilä, Timo; Ojanen, Paavo; Launiainen, Samuli; Laurila, Tuomas

2016-04-01

Forestry on peatlands is a significant land use form and has been economically important during the last decades particularly in the Nordic countries. While nutrient-poor forests are generally able to maintain their carbon sink status even after drainage, the peat soil at the fertile sites is typically considered as a large carbon dioxide (CO2) source. This means that despite of high timber production capacity, the fertile peatland forests gradually lose their peat carbon store. In addition, many of the nutrient-rich sites emit considerable amount of nitrous oxide (N2O) into the atmosphere. While the current estimates of the greenhouse gas (GHG) balance of forestry-drained peatlands are largely based on soil inventories or on data combining soil GHG fluxes and tree growth litter input measurements and modelling, only few studies have utilized the high-resolution, continuous eddy covariance (EC) data to address the short-term dynamics of the net CO2 fluxes covering both the soil, forest floor vegetation and the trees. Hence, little is known about the factors which control the year-to-year variation in fluxes. Here we present a 5-year dataset of CO2 fluxes measured with the EC method above a nutrient-rich forestry-drained peatland in southern Finland. The site, drained in the beginning of 1970's, is a well growing pine forest with some spruces and birches, the tree volume and carbon fixation rate equaling 8.0 kg C m-2 and 0.273 kg C m-2 yr-1, respectively. The average summer-time water level depth is -50 cm. By combining the gap-filled half-hourly net ecosystem exchange (NEE) data, the tree growth measurements, and the measurements on dissolved organic carbon (DOC) losses and soil methane (CH4) exchange, we will in this presentation estimate the total annual loss of peat carbon of this fertile peatland forest. In addition, using the N2O flux data we will estimate the contribution of different gases to the total GHG balance. Factors controlling the carbon balance and its seasonal and inter-annual variation are discussed.

Pleistocene atmospheric CO2 change linked to Southern Ocean nutrient utilization

NASA Astrophysics Data System (ADS)

Ziegler, M.; Diz, P.; Hall, I. R.; Zahn, R.

2011-12-01

Biological uptake of CO2 by the ocean and its subsequent storage in the abyss is intimately linked with the global carbon cycle and constitutes a significant climatic force1. The Southern Ocean is a particularly important region because its wind-driven upwelling regime brings CO2 laden abyssal waters to the surface that exchange CO2 with the atmosphere. The Subantarctic Zone (SAZ) is a CO2 sink and also drives global primary productivity as unutilized nutrients, advected with surface waters from the south, are exported via Subantarctic Mode Water (SAMW) as preformed nutrients to the low latitudes where they fuel the biological pump in upwelling areas. Recent model estimates suggest that up to 40 ppm of the total 100 ppm atmospheric pCO2 reduction during the last ice age were driven by increased nutrient utilization in the SAZ and associated feedbacks on the deep ocean alkalinity. Micro-nutrient fertilization by iron (Fe), contained in the airborne dust flux to the SAZ, is considered to be the prime factor that stimulated this elevated photosynthetic activity thus enhancing nutrient utilization. We present a millennial-scale record of the vertical stable carbon isotope gradient between subsurface and deep water (Δδ13C) in the SAZ spanning the past 350,000 years. The Δδ13C gradient, derived from planktonic and benthic foraminifera, reflects the efficiency of biological pump and is highly correlated (rxy = -0.67 with 95% confidence interval [0.63; 0.71], n=874) with the record of dust flux preserved in Antarctic ice cores6. This strongly suggests that nutrient utilization in the SAZ was dynamically coupled to dust-induced Fe fertilization across both glacial-interglacial and faster millennial timescales. In concert with ventilation changes of the deep Southern Ocean this drove ocean-atmosphere CO2 exchange and, ultimately, atmospheric pCO2 variability during the late Pleistocene.

[Effects of Water and Nitrogenous Fertilizer Coupling on CH4 and N2O Emission from Double-Season Rice Paddy Field].

PubMed

Fu, Zhi-qiang; Long, Pan; Liu, Yi-yi; Zhong, Juan; Long, Wen-fei

2015-09-01

To provide support for the efficient use of water and fertilizer technology to double-season rice cultivation, water and fertilizer coupling mode was applied in this research, including two irrigation methods and four N levels. The irrigation methods were flood irrigation and intermittent irrigation, while four N levels were high-N, middle-N, low-N and none-N. Field experiment was conducted to study the effect of water and fertilizer coupling mode on CH4 and N2O emission. The results showed that the accumulated CH4 emissions were significantly reduced by intermittent irrigation, in comparison with flood irrigation, the reduction in early rice season were from 13. 18 kg.hm-2 to 87. 90 kg.hm-2, and were from 74. 48 kg.hm-2 to 131. 07 kg.hm-2 in late rice season, with a rate of 24. 4% -67. 4% and 42. 5% -65. 5% respectively; whereas the accumulated N20 emissions were increased, the increment were from 0. 03 kg.hm-2 to 0. 24 kg.hm-2 in early rice season and from 0. 35 kg.hm-2 to 1. 53 kg.hm-2 in late rice season when compared flood irrigation, increased by 6.2% -18. 3% and 40.2% - 80.9% respectively. On the whole, intermittent irrigation reduces the warming potential of greenhouse gases (GWP), which were decreased by 18. 8% to 58. 6% in early rice season and by 34. 4% to 60. 1% in late rice season, and the reduction of total GWP were from 2 388 to 4 151 kg. hm-2 (CO2 eq), with a rate of 41% -54% . Through correlation analysis it found that CH4 emissions from soil were significantly related with soil solution Eh and solution CH4 concentration. In comparison with the flood irrigation, the application of intermittent irrigation in double-season rice cultivation was conducive to CH4 reduction, though the increase came in N2O, but the GWPs were significantly reduced. Comprehensively, intermittent irrigation matching with middle-N is more benefit to double-season rice cultivation.

Greenhouse gas emissions during co-composting of calf mortalities with manure.

PubMed

Xu, Shanwei; Hao, Xiying; Stanford, Kim; McAllister, Tim A; Larney, Francis J; Wang, Jingguo

2007-01-01

Composting may be a viable on-farm option for disposal of cattle carcasses. This study investigated greenhouse gas emissions during co-composting of calf mortalities with manure. Windrows were constructed that contained manure + straw (control compost [CK]) or manure + straw + calf mortalities (CM) using two technologies: a tractor-mounted front-end loader or a shredder bucket. Composting lasted 289 d. The windrows were turned twice (on Days 72 and 190), using the same technology used in their creation. Turning technology had no effect on greenhouse gas emissions or the properties of the final compost. The CO2 (75.2 g d(-1) m(-2)), CH4 (2.503 g d(-1) m(-2)), and N2O (0.370 g d(-1) m(-2)) emissions were higher (p < 0.05) in CM than in CK (25.7, 0.094, and 0.076 g d(-1) m(-2) for CO2, CH4, and N2O, respectively), which reflected differences in materials used to construct the compost windrows and therefore their total C and total N contents. The final CM compost had higher (p < 0.05) total N, total C, and mineral N content (NO3*+ NO2* + NH4+) than did CK compost and therefore has greater agronomic value as a fertilizer.

Carbon Cycle Model Linkage Project (CCMLP): Evaluating Biogeochemical Process Models with Atmospheric Measurements and Field Experiments

NASA Astrophysics Data System (ADS)

Heimann, M.; Prentice, I. C.; Foley, J.; Hickler, T.; Kicklighter, D. W.; McGuire, A. D.; Melillo, J. M.; Ramankutty, N.; Sitch, S.

2001-12-01

Models of biophysical and biogeochemical proceses are being used -either offline or in coupled climate-carbon cycle (C4) models-to assess climate- and CO2-induced feedbacks on atmospheric CO2. Observations of atmospheric CO2 concentration, and supplementary tracers including O2 concentrations and isotopes, offer unique opportunities to evaluate the large-scale behaviour of models. Global patterns, temporal trends, and interannual variability of the atmospheric CO2 concentration and its seasonal cycle provide crucial benchmarks for simulations of regionally-integrated net ecosystem exchange; flux measurements by eddy correlation allow a far more demanding model test at the ecosystem scale than conventional indicators, such as measurements of annual net primary production; and large-scale manipulations, such as the Duke Forest Free Air Carbon Enrichment (FACE) experiment, give a standard to evaluate modelled phenomena such as ecosystem-level CO2 fertilization. Model runs including historical changes of CO2, climate and land use allow comparison with regional-scale monthly CO2 balances as inferred from atmospheric measurements. Such comparisons are providing grounds for some confidence in current models, while pointing to processes that may still be inadequately treated. Current plans focus on (1) continued benchmarking of land process models against flux measurements across ecosystems and experimental findings on the ecosystem-level effects of enhanced CO2, reactive N inputs and temperature; (2) improved representation of land use, forest management and crop metabolism in models; and (3) a strategy for the evaluation of C4 models in a historical observational context.

Net carbon flux in organic and conventional olive production systems

NASA Astrophysics Data System (ADS)

Saeid Mohamad, Ramez; Verrastro, Vincenzo; Bitar, Lina Al; Roma, Rocco; Moretti, Michele; Chami, Ziad Al

2014-05-01

Agricultural systems are considered as one of the most relevant sources of atmospheric carbon. However, agriculture has the potentiality to mitigate carbon dioxide mainly through soil carbon sequestration. Some agricultural practices, particularly fertilization and soil management, can play a dual role in the agricultural systems regarding the carbon cycle contributing to the emissions and to the sequestration process in the soil. Good soil and input managements affect positively Soil Organic Carbon (SOC) changes and consequently the carbon cycle. The present study aimed at comparing the carbon footprint of organic and conventional olive systems and to link it to the efficiency of both systems on carbon sequestration by calculating the net carbon flux. Data were collected at farm level through a specific and detailed questionnaire based on one hectare as a functional unit and a system boundary limited to olive production. Using LCA databases particularly ecoinvent one, IPCC GWP 100a impact assessment method was used to calculate carbon emissions from agricultural practices of both systems. Soil organic carbon has been measured, at 0-30 cm depth, based on soil analyses done at the IAMB laboratory and based on reference value of SOC, the annual change of SOC has been calculated. Substracting sequestrated carbon in the soil from the emitted on resulted in net carbon flux calculation. Results showed higher environmental impact of the organic system on Global Warming Potential (1.07 t CO2 eq. yr-1) comparing to 0.76 t CO2 eq. yr-1 in the conventional system due to the higher GHG emissions caused by manure fertilizers compared to the use of synthetic foliar fertilizers in the conventional system. However, manure was the main reason behind the higher SOC content and sequestration in the organic system. As a resultant, the organic system showed higher net carbon flux (-1.7 t C ha-1 yr-1 than -0.52 t C ha-1 yr-1 in the conventional system reflecting higher efficiency as a sink for atmospheric CO2 (the negative value of Net C flux indicates that a system is a net sink for atmospheric CO2). In conclusion, this study illustrates the importance of including soil carbon sequestration associated with CO2 emissions in the evaluation process between alternatives of agricultural systems. Thus, organic olive system offers an opportunity to increase carbon sequestration compared to the conventional one although it causes higher C emissions from manure fertilization. Keywords: Net carbon flux, GHG, organic, olive, soil organic carbon

Impaired sperm fertilizing ability in mice lacking Cysteine-RIch Secretory Protein 1 (CRISP1)

PubMed Central

Da Ros, Vanina G.; Maldera, Julieta A.; Willis, William D.; Cohen, Débora J.; Goulding, Eugenia H.; Gelman, Diego M.; Rubinstein, Marcelo; Eddy, Edward M.; Cuasnicu, Patricia S.

2008-01-01

Mammalian fertilization is a complex multi-step process mediated by different molecules present on both gametes. Epididymal protein CRISP1, a member of the Cysteine-RIch Secretory Protein (CRISP) family, was identified by our laboratory and postulated to participate in both sperm-zona pellucida (ZP) interaction and gamete fusion by binding to egg-complementary sites. To elucidate the functional role of CRISP1 in vivo, we disrupted the Crisp1 gene and evaluated the effect on animal fertility and several sperm parameters. Male and female Crisp1−/− animals exhibited no differences in fertility compared to controls. Sperm motility and the ability to undergo a spontaneous or progesterone-induced acrosome reaction were neither affected in Crisp1−/− mice. However, the level of protein tyrosine phosphorylation during capacitation was clearly lower in mutant sperm than in controls. In vitro fertilization assays showed that Crisp1−/− sperm also exhibited a significantly reduced ability to penetrate both ZP-intact and ZP-free eggs. Moreover, when ZP-free eggs were simultaneously inseminated with Crisp1+/+ and Crisp1−/− sperm in a competition assay, the mutant sperm exhibited a greater disadvantage in their fusion ability. Finally, the finding that the fusion ability of Crisp1−/− sperm was further inhibited by the presence of CRISP1 or CRISP2 during gamete co-incubation, supports that another CRISP cooperates with CRISP1 during fertilization and might compensate for its lack in the mutant mice. Together, these results indicate that CRISP proteins are players in the mammalian fertilization process. To our knowledge this is the first knockout mice generated for a CRISP protein. The information obtained might have important functional implications for other members of the widely distributed and evolutionarily conserved CRISP family. PMID:18571638

Potential GHG mitigation options for agriculture in China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erda, Lin; Yue, Li; Hongmin, Dong

1996-12-31

Agriculture contributes more or less to anthropogenic emissions of carbon dioxide (CO{sub 2}), methane (CH{sub 4}), and nitrous oxide (N{sub 2}O). China`s agriculture accounts for about 5-15% of total emissions for these gases. Land-use changes related to agriculture are not major contributors in China. Mitigation options are available that could result in significant decrease in CH{sub 4} and N{sub 2}O emissions from agricultural systems. If implemented, they are likely to increase crop and animal productivity. Implementation has the potential to decrease CH{sub 4} emissions from rice, ruminants, and animal waste by 4-40%. The key to decreasing N{sub 2}O emissions ismore » improving the efficiency of plant utilization of fertilizer N. This could decrease N{sub 2}O emissions from agriculture by almost 20%. Using animal waste to produce CH{sub 4} for energy and digested manure for fertilizer may at some time be cost effective. Economic analyses of options proposed should show positive economic as well as environmental benefits.« less

The effect of follicle age on conception rate in beef heifers

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the effect of age of the ovulatory follicle on fertility in beef heifers. Ovulation was synchronized with the 5 d CO-Synch + CIDR program in heifers in Montana (n = 162, Hereford and Angus Crossbred; MT) and Ohio (n = 170, Angus Crossbred; OH). All heifer...

Soil greenhouse gas (GHG) emissions from smallholder crop-livestock systems in Central Kenya

NASA Astrophysics Data System (ADS)

Ortiz Gonzalo, Daniel; Vaast, Philippe; de Neergaard, Andreas; Oelofse, Myles; Albrecht, Alain; Rosenstock, Todd S.

2017-04-01

Few studies measured empirically greenhouse gas (GHG) emissions in sub-Saharan Africa. More specifically, there is no experimental data on GHG emissions from coffee systems in East Africa and estimations with GHG calculators have shown some limitations. The objectives of our study are to: 1) Quantify soil GHG fluxes in smallholder coffee-dairy farms in Central Kenya and; 2) Compare results with the GHG emissions estimated with GHG calculators. The study area is situated in Murang'a County at 1700 m.a.s.l. on the Eastern slopes of the Aberdares Range, where coffee (Coffee arabica) is cultivated within integrated crop-livestock-agroforestry systems. We carried out GHG measurements along two cropping seasons using non-flow through non-steady static chambers. Sixty rectangular frames (0.355m x 0.255m) were installed at two representative farms, including the three main cropping systems found in the area: 1) Coffee (Coffee arabica); 2) Napier grass (Pennisetum purpureum); 3) Maize intercropped with beans (Zea mays and Phaseolus vulgaris). We used the gas pooling technique to overcome spatial variability and obtain a composite sample from the two treatment chambers: fertilized and non-fertilized. The sampling was performed twice per week during the rainy season and once per week during the dry season. Fertilizer and manure applications were followed by daily measurements during seven days after application. Annual fluxes (cumulative) in coffee plots ranged from 0.8 to 2.1 kg N2O-N ha-1, 6.3 to 8.2 Mg CO2-C ha-1 and -1.3 to -0.8 kg CH4-C ha-1, with higher fluxes during the rainy seasons. Emissions of N2O and CO2 from coffee plots were 20 to 80% higher than those in maize and napier grass. We found significant higher emissions in fertilized hot-spots (45 -190 % higher around coffee bushes perimeter, within maize rows and in napier holes) than in non-fertilized locations (between trees, between rows and between holes). Though this aspect is crucial for upscaling the emissions to farm scale, it is not always accounted in empirical models. GHG calculators overestimated both background and induced soil N2O emissions from fertilizer and manure applications in the three cropping systems. Our study contributes to the generation of underlying data and emission factors (EFs) for quantifying GHG emissions in tropical farming systems.

[Effects of alkaline fertilizer on cadmium content in rice and paddy soil.

PubMed

Zhang, Liang Liang; Fan, Xiao Lin; Zhang, Li Dan; Liu, Fang

2016-03-01

A field plot trial was conducted at Songbai Village, Chenzhou, Hunan Province to exa-mine the effects of alkaline fertilizer with and without combination application of bacterial regent on cadmium accumulation in rice and paddy soil. Compared with the conventional fertilizer, the alkaline fertilizer reduced the available cadmium content in soil at the tillering, filling and the harvest stages by 8.3%, 6.7% and 16.4% respectively. Compared with the Cd content in soil before transplanting, it was reduced by 7.2% at harvest time in alkaline fertilizer treatment, while increased by 11.0% in the conventional fertilizer treatment. The available cadmium content in soil was increased by 1.2% to 23.3% by bacterial regent. Compared with the conventional fertilizer, the cadmium content of root, stem sheath, leaf, grain and brown rice of the alkaline fertilizer treatment reduced by 54.9%, 56.6%, 41.8%, 62.7% and 67.6% respectively. The alkaline fertilizer treatment combined with bacterial regent increased the cadmium content of brown rice by 63.2%. It was concluded that the alkaline fertilizer could significantly reduce the available cadmium content in both soil and the different organs of the rice, however, when it was combined with bacterial regent together, the effect of alkaline fertilizer to reduce Cd content of brown rice would be declined.

High Resolution Modelling of Crop Response to Climate Change

NASA Astrophysics Data System (ADS)

Mirmasoudi, S. S.; Byrne, J. M.; MacDonald, R. J.; Lewis, D.

2014-12-01

Crop production is one of the most vulnerable sectors to climatic variability and change. Increasing atmospheric CO2 concentration and other greenhouse gases are causing increases in global temperature. In western North America, water supply is largely derived from mountain snowmelt. Climate change will have a significant impact on mountain snowpack and subsequently, the snow-derived water supply. This will strain water supplies and increase water demand in areas with substantial irrigation agriculture. Increasing temperatures may create heat stress for some crops regardless of soil water supply, and increasing surface O3 and other pollutants may damage crops and ecosystems. CO2 fertilization may or may not be an advantage in future. This work is part of a larger study that will address a series of questions based on a range of future climate scenarios for several watersheds in western North America. The key questions are: (1) how will snowmelt and rainfall runoff vary in future; (2) how will seasonal and inter-annual soil water supply vary, and how might that impacts food supplies; (3) how might heat stress impact (some) crops even with adequate soil water; (4) will CO2 fertilization alter crop yields; and (5) will pollution loads, particularly O3, cause meaningful changes to crop yields? The Generate Earth Systems Science (GENESYS) Spatial Hydrometeorological Model is an innovative, efficient, high-resolution model designed to assess climate driven changes in mountain snowpack derived water supplies. We will link GENESYS to the CROPWAT crop model system to assess climate driven changes in water requirement and associated crop productivity for a range of future climate scenarios. Literature bases studies will be utilised to develop approximate crop response functions for heat stress, CO2 fertilization and for O3 damages. The overall objective is to create modeling systems that allows meaningful assessment of agricultural productivity at a watershed scale under a range of climate scenarios.

Potential of global croplands and bioenergy crops for climate change mitigation through deployment for enhanced weathering.

PubMed

Kantola, Ilsa B; Masters, Michael D; Beerling, David J; Long, Stephen P; DeLucia, Evan H

2017-04-01

Conventional row crop agriculture for both food and fuel is a source of carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) to the atmosphere, and intensifying production on agricultural land increases the potential for soil C loss and soil acidification due to fertilizer use. Enhanced weathering (EW) in agricultural soils-applying crushed silicate rock as a soil amendment-is a method for combating global climate change while increasing nutrient availability to plants. EW uses land that is already producing food and fuel to sequester carbon (C), and reduces N 2 O loss through pH buffering. As biofuel use increases, EW in bioenergy crops offers the opportunity to sequester CO 2 while reducing fossil fuel combustion. Uncertainties remain in the long-term effects and global implications of large-scale efforts to directly manipulate Earth's atmospheric CO 2 composition, but EW in agricultural lands is an opportunity to employ these soils to sequester atmospheric C while benefitting crop production and the global climate. © 2017 The Author(s).

The effect of polymer dots on bioactivity of mouse sperm in vitro

NASA Astrophysics Data System (ADS)

Feng, Gang; Chen, Qiang; Zhai, Peng; Wang, Xiaomei; Lin, Guimiao; Xu, Gaixia; Chen, Danni

2014-09-01

Objective: In recent years, semiconducting polymer dots (Pdots)have caught considerable attention for their outstanding optical characteristics in biomedical imaging applications. Not as semiconductor quantum dots, Pdots are composed of nonmetallic material and their biological effects remain unclear. In this work, we investigated the effects of a band new polymer dots on bioactivity of mouse sperm using a computer-aided sperm analysis system(CASA) and an in vitro fertilization (IVF) model. Methods: The semiconducting polymer dots used in this study is CN-PPV Pdots, which emits in the orange wavelength range with high brightness. Epididymal mouse sperm were collected from 7-8weeks old Balb/c mouse. Firstly, CN-PPV Pdots was added into the Human Tubal Fluid (HTF) media at various concentrations (0, 1, 10, 100 nmol/L respectively ), then sperm bioactivity and vitality were evaluated every 10 minutes. Secondly, the treated sperm were co-cultured with matured oocytes in HTF media, fertilization rate and oocytes development were recorded after 24 hours co-incubation. Results: Sperm viability in the control group (0 nmol/L) and experimental group (1, 10,100 nmol/L) were 57.20+/-4.51%, 58.17+/-4.81%, 55.50+/-4.52%, 46.26%+/-3.83%, respectively. Fertilization rate in different groups showed no obvious differences, control group (0 nmol/L) and experimental group (1, 10, 100 nmol/L) were 38.75+/-1.71%, 37.01+/-4.69%, 32.75+/-1.71%, 35.24+/-2.37%, respectively. Conclusion: Our data indicated that the CN-PPV Pdots had a very high biocompatibility on sperm in both the activation and the IVF process, even in extreme high Pdots concentration,the sperm bioactivity only got slight restrained. The effect of CN-PPV Pdots seems has no or little toxicity,and the long-term embryonic development has yet to be verified.

Natural radioactivity levels and heavy metals in chemical and organic fertilizers used in Kingdom of Saudi Arabia.

PubMed

El-Taher, A; Althoyaib, S S

2012-01-01

The present work deals with identifying and determining the activity levels of natural occuring radionuclides, (226)Ra and (232)Th series, their decay products and (40)K, in chemical and organic fertilizers used in Kingdom of Saudi Arabia. A total of 30 samples: 20 phosphatic fertilizers (single super-phosphate SSP and triple super-phosphate,TSP) and 10 organic fertilizers (cow, sheep and chicken) collected from markets and farms. The gamma-ray spectrometer consists of NaI(Tl) detector and its electronic circuit was used for measuring γ-ray spectra. The ranges of radioactivity levels of (226)Ra, (232)Th and (40)K in chemical fertilizers are 51.5±5.2-106.3±7.5, 5.1±1.6-9.9±3.2. and 462.6±21-607.3±14Bqkg(-1), respectively. The activities of (226)Ra, (232)Th and (40)K in natural fertilizers (cow, sheep and chicken) are lower than the activities in chemical fertilizers. The obtained data are compared with available reported data from other countries in literature. The Ra(eq) in chemical fertilizer ranges from 100.37 to 161.43Bqkg(-1) and in organic fertilizer ranges from 34.07 to 102.19Bqkg(-1), which are lower than the limit of 370Bqkg(-1) adopted from NEA-OECD (1979). The average heavy metal (Pb, Cd, Ni, Co and Cr) contents of the fertilizers marketed in the Kingdom of Saudi Arabia are also determined and within the limits of those used worldwide. Copyright © 2011 Elsevier Ltd. All rights reserved.