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Sample records for nitrogen leaching losses

  1. Arbuscular mycorrhizas reduce nitrogen loss via leaching.

    PubMed

    Asghari, Hamid R; Cavagnaro, Timothy R

    2012-01-01

    The capacity of mycorrhizal and non-mycorrhizal root systems to reduce nitrate (NO₃⁻) and ammonium (NH₄⁺) loss from soils via leaching was investigated in a microcosm-based study. A mycorrhiza defective tomato mutant and its mycorrhizal wildtype progenitor were used in this experiment in order to avoid the indirect effects of establishing non-mycorrhizal control treatments on soil nitrogen cycling and the wider soil biota. Mycorrhizal root systems dramatically reduced nitrate loss (almost 40 times less) via leaching, compared to their non-mycorrhizal counterparts, following a pulse application of ammonium nitrate to experimental microcosms. The capacity of AM to reduce nutrient loss via leaching has received relatively little attention, but as demonstrated here, can be significant. Taken together, these data highlight the need to consider the potential benefits of AM beyond improvements in plant nutrition alone.

  2. Catch crops as universal and effective method for reducing nitrogen leaching loss in spring cereal production: A meta-analysis.

    NASA Astrophysics Data System (ADS)

    Valkama, Elena; Lemola, Riitta; Känkänen, Hannu; Turtola, Eila

    2016-04-01

    Sustainable farms produce adequate amounts of a high-quality product, protect their resources and are both environmentally friendly and economically profitable. Nitrogen (N) fertilization decisively influences the cereal yields as well as increases soil N balance (N input in fertilizer - N output in harvested yield), thereby leading to N losses to the environment. However, while N input reduction affects soil N balance, such approach would markedly reduce N leaching loss only in case of abnormally high N balances. As an alternative approach, the growing of catch crops aims to prevent nutrient leaching in autumn after harvest and during the following winter, but due to competition, catch crops may also reduce yields of the main crop. Although studies have explored the environmental effects of catch crops in cereal production in the Nordic countries (Denmark, Sweden, Finland and Norway) during the past 40 years, none has yet carried out a meta-analysis. We quantitatively summarized 35 studies on the effect of catch crops (non-legume and legume) undersown in spring cereals on N leaching loss or its risk as estimated by the content of soil nitrate N or its sum with ammonium in late autumn. The meta-analysis also included the grain yield and N content of spring cereals. To identify sources of variation, we studied the effects of soil texture and management (ploughing time, the amount of N applied, fertilizer type), as well as climatic (annual precipitation) and experimental conditions (duration of experiments, lysimeter vs. field experiments). Finally, we examined whether the results differed between the countries or over the decades. Compared to control groups with no catch crops, non-legume catch crops, mainly ryegrass species, reduced N leaching loss by 50% on average, and soil nitrate N or inorganic N by 35% in autumn. Italian ryegrass depleted soil N more effectively (by 60%) than did perennial ryegrass or Westerwolds ryegrass (by 25%). In contrast, legumes (white

  3. Nitrogen mobility, ammonia volatilization, and estimated leaching loss from long-term manure incorporation in red soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) loss from fertilization in agricultural fields has an unavoidable negative impact on the environment, and a better understanding of the major pathways can assist in developing best management practices. The aim of this study was to evaluate the fate of N fertilizers applied to acidic re...

  4. Nitrogen loss from Titan

    NASA Astrophysics Data System (ADS)

    Shematovich, V. I.; Johnson, R. E.; Michael, M.; Luhmann, J. G.

    2003-08-01

    Dissociation and dissociative ionization of molecular nitrogen by solar UV radiation and by photoelectrons and sputtering by the magnetospheric ions and pickup ions are the main sources of translationally excited (hot) nitrogen atoms and molecules in the upper atmosphere of Titan. As Titan does not posses an intrinsic magnetic field, Saturn's magnetospheric ions can penetrate Titan's exobase and sputter atoms and molecules from it. The sputtering of nitrogen from Titan's upper atmosphere by the corotating nitrogen ions and by photodissociation was addressed earlier [Lammer and Bauer, 1993; Shematovich et al., 2001]. Here penetration of slowed and deflected magnetospheric N+ and carbon-containing pickup ions is described using a Monte Carlo model. The interaction of these ions with the atmospheric neutrals leads to the production of fast neutrals that collide with other atmospheric neutrals producing heating and ejection of atoms and molecules. Results from Brecht et al. [2000] are used to estimate the net flux and energy spectra of the magnetospheric and pickup ions onto the exobase. Sputtering is primarily responsible for any ejected molecular nitrogen, and, for the ion fluxes used, we show that the total sputtering contribution is comparable to or larger than the dissociation contribution giving a total loss rate of ~3.6 × 1025 nitrogen neutrals per second.

  5. Denitrification, leaching, and river nitrogen export in the Community Earth System Model

    NASA Astrophysics Data System (ADS)

    Nevison, Cynthia; Hess, Peter; Riddick, Stuart; Ward, Dan

    2016-03-01

    River nitrogen export is simulated within the Community Earth System Model (CESM) by coupling nitrogen leaching and runoff fluxes from the Community Land Model (CLM) to the River Transport Model (RTM). The coupled CLM-RTM prognostically simulates the downstream impact of human N cycle perturbation on coastal areas. It also provides a framework for estimating denitrification fluxes of N2 and associated trace gases like N2O in soils and river sediments. An important limitation of the current model is that it only simulates dissolved inorganic nitrogen (DIN) river export, due to the lack of dissolved organic nitrogen (DON) and particulate nitrogen (PN) leaching fluxes in CLM. In addition, the partitioning of soil N loss in CLM between the primary loss pathways of denitrification and N leaching/runoff appears heavily skewed toward denitrification compared to other literature estimates, especially in nonagricultural regions, and also varies considerably among the four model configurations presented here. River N export is generally well predicted in the model configurations that include midlatitude crops, but tends to be underpredicted in rivers that are less perturbed by human agriculture. This is especially true in the tropics, where CLM likely underestimates leaching and runoff of all forms of nitrogen. River export of DIN is overpredicted in some relatively unperturbed Arctic rivers, which may result from excessive N inputs to those regions in CLM. Better representation of N loss in CLM can improve confidence in model results with respect to the core model objective of simulating nitrogen limitation of the carbon cycle.

  6. Nitrogen leaching from Douglas-fir forests after urea fertilization.

    PubMed

    Flint, Cynthia M; Harrison, Rob B; Strahm, Brian D; Adams, A B

    2008-01-01

    Leaching of nitrogen (N) after forest fertilization has the potential to pollute ground and surface water. The purpose of this study was to quantify N leaching through the primary rooting zone of N-limited Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] forests the year after fertilization (224 kg N ha(-1) as urea) and to calculate changes in the N pools of the overstory trees, understory vegetation, and soil. At six sites on production forests in the Hood Canal watershed, Washington, tension lysimeters and estimates of the soil water flux were used to quantify the mobilization and leaching of NO(3)-N, NH(4)-N, and dissolved organic nitrogen below the observed rooting depth. Soil and vegetation samples were collected before fertilization and 1 and 6 mo after fertilization. In the year after fertilization, the total leaching beyond the primary rooting zone in excess of control plots was 4.2 kg N ha(-1) (p = 0.03), which was equal to 2% of the total N applied. The peak NO(3)-N concentration that leached beyond the rooting zone of fertilized plots was 0.2 mg NO(3)-N L(-1). Six months after fertilization, 26% of the applied N was accounted for in the overstory, and 27% was accounted for in the O+A horizon of the soil. The results of this study indicate that forest fertilization can lead to small N leaching fluxes out of the primary rooting zone during the first year after urea application.

  7. Identification of nitrate leaching loss indicators through regression methods based on a meta-analysis of lysimeter studies.

    PubMed

    Boy-Roura, M; Cameron, K C; Di, H J

    2016-02-01

    This study presents a meta-analysis of 12 experiments that quantify nitrate-N leaching losses from grazed pasture systems in alluvial sedimentary soils in Canterbury (New Zealand). Mean measured nitrate-N leached (kg N/ha × 100 mm drainage) losses were 2.7 when no urine was applied, 8.4 at the urine rate of 300 kg N/ha, 9.8 at 500 kg N/ha, 24.5 at 700 kg N/ha and 51.4 at 1000 kg N/ha. Lismore soils presented significantly higher nitrate-N losses compared to Templeton soils. Moreover, a multiple linear regression (MLR) model was developed to determine the key factors that influence nitrate-N leaching and to predict nitrate-N leaching losses. The MLR analyses was calibrated and validated using 82 average values of nitrate-N leached and 48 explanatory variables representative of nitrogen inputs and outputs, transport, attenuation of nitrogen and farm management practices. The MLR model (R (2) = 0.81) showed that nitrate-N leaching losses were greater at higher urine application rates and when there was more drainage from rainfall and irrigation. On the other hand, nitrate leaching decreased when nitrification inhibitors (e.g. dicyandiamide (DCD)) were applied. Predicted nitrate-N leaching losses at the paddock scale were calculated using the MLR equation, and they varied largely depending on the urine application rate and urine patch coverage.

  8. Nitrogen losses from perennial grass species.

    PubMed

    Vázquez de Aldana, B R; Geerts, R H E M; Berendse, F

    1996-04-01

    Nitrogen losses from plants may occur through a variety of pathways, but so far, most studies have only quantified losses of nutrients by above-ground litter production. We used (15)N pulse labelling to quantify total nitrogen losses from above- and below-ground plant parts. Using this method we were able to include also pathways other than above-ground litter production. To test the hypothesis that species from nutrient-poor habitats lose less nitrogen than species from more fertile soils, six perennial grasses from habitats with a wide range of nutrient availability were investigated: Lolium perenne, Arrhenatherum elatius, Anthoxanthum odoratum, Festuca rubra, F. ovina and Molinia caerulea. The results of an experiment carried out in pots in a green-house at two fertility levels show that statistically significant losses occur through pathways other than above-ground litter production. In the low fertility treatment, most (70%) losses from L. perenne occurred by litter production, but in Ar. elatius, F. rubra, F. ovina and M. caerulea, more than 50% of labelled N losses took place by root turn-over, leaching or exudation from roots. When nutrient supply increased, the (15)N losses in above-ground dead material increased in all species and in Ar. elatius, A. odoratum and F. rubra the (15)N losses via other pathways decreased. Ranked according to decreasing turnover coefficient the sequence of species was: L. perenne, A. odoratum, F. rubra, F. ovina, Ar. elatius, M. caerulea. These results suggest that species adapted to sites with low availability of nutrients lose less nitrogen (including above- and below-ground losses) than species adapted to more fertile soils.

  9. Phosphorus and nitrogen leaching before and after tillage and urea application.

    PubMed

    Han, Kun; Kleinman, Peter J A; Saporito, Lou S; Church, Clinton; McGrath, Joshua M; Reiter, Mark S; Tingle, Shawn C; Allen, Arthur L; Wang, L Q; Bryant, Ray B

    2015-03-01

    Leaching of nutrients through agricultural soils is a priority water quality concern on the Atlantic Coastal Plain. This study evaluated the effect of tillage and urea application on leaching of phosphorus (P) and nitrogen (N) from soils of the Delmarva Peninsula that had previously been under no-till management. Intact soil columns (30 cm wide × 50 cm deep) were irrigated for 6 wk to establish a baseline of leaching response. After 2 wk of drying, a subset of soil columns was subjected to simulated tillage (0-20 cm) in an attempt to curtail leaching of surface nutrients, especially P. Urea (145 kg N ha) was then broadcast on all soils (tilled and untilled), and the columns were irrigated for another 8 wk. Comparison of leachate recoveries representing rapid and slow flows confirmed the potential to manipulate flow fractions with tillage, albeit with mixed results across soils. Leachate trends in the finer-textured soil suggest that tillage impeded macropore flow and forced greater matrix flow. Despite significant vertical stratification of soil P that suggested tillage could prevent leaching of P via macropores from the surface to the subsoil, tillage had no significant impact on P leaching losses. Relatively high levels of soil P below 20 cm may have served as the source of P enrichment in leachate waters. However, tillage did lower losses of applied urea in leachate from two of the three soils, partially confirming the study's premise that tillage would destroy macropore pathways transmitting surface constituents to the subsoil.

  10. Quantifying nitrogen leaching response to fertilizer additions in China's cropland.

    PubMed

    Gao, Shuoshuo; Xu, Peng; Zhou, Feng; Yang, Hui; Zheng, Chunmiao; Cao, Wei; Tao, Shu; Piao, Shilong; Zhao, Yue; Ji, Xiaoyan; Shang, Ziyin; Chen, Minpeng

    2016-04-01

    Agricultural soils account for more than 50% of nitrogen leaching (LN) to groundwater in China. When excess levels of nitrogen accumulate in groundwater, it poses a risk of adverse health effects. Despite this recognition, estimation of LN from cropland soils in a broad spatial scale is still quite uncertain in China. The uncertainty of LN primarily stems from the shape of nitrogen leaching response to fertilizer additions (N rate) and the role of environmental conditions. On the basis of 453 site-years at 51 sites across China, we explored the nonlinearity and variability of the response of LN to N rate and developed an empirical statistical model to determine how environmental factors regulate the rate of N leaching (LR). The result shows that LN-N rate relationship is convex for most crop types, and varies by local hydro-climates and soil organic carbon. Variability of air temperature explains a half (∼ 52%) of the spatial variation of LR. The results of model calibration and validation indicate that incorporating this empirical knowledge into a predictive model could accurately capture the variation in leaching and produce a reasonable upscaling from site to country. The fertilizer-induced LN in 2008 for China's cropland were 0.88 ± 0.23 TgN (1σ), significantly lower than the linear or uniform model, as assumed by Food and Agriculture Organization and MITERRA-EUROPE models. These results also imply that future policy to reduce N leaching from cropland needs to consider environmental variability rather than solely attempt to reduce N rate.

  11. Evaluation of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen leaching in undisturbed soil columns.

    PubMed

    Yu, Qiaogang; Chen, Yingxu; Ye, Xuezhu; Zhang, Qiuling; Zhang, Zhijian; Tian, Ping

    2007-03-01

    The application of nitrogen fertilizers leads to various ecological problems such as nitrate leaching. The use of nitrification inhibitors (NI) as nitrate leaching retardants is a proposal that has been suggested for inclusion in regulations in many countries. In this study, the efficacy of the new NI, 3,4-dimethyl pyrazole phosphate (DMPP), was tested under simulated high-risk leaching situations in two types of undisturbed soil columns. The results showed that the accumulative leaching losses of soil nitrate under treatment of urea with 1.0% DMPP, from columns of silt loam soil and heavy clay soil, were 66.8% and 69.5% lower than those soil columns tested with regular urea application within the 60 days observation, respectively. However, the losses of ammonium leaching were reversely increased 9.7% and 6.7% under the former treatment than the latter one. Application of regular urea with 1.0% DMPP addition can reduce about 59.3%-63.1% of total losses of inorganic nitrogen via leaching. The application of DMPP to urea had stimulated the inhibition effects of DMPP on the ammonium nitrification process in the soil up to 60 days. It is proposed that the DMPP could be used as an effective NI to control inorganic N leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.

  12. Influences of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen and soil salt-ion leaching.

    PubMed

    Yu, Qiaogang; Ye, Xuezhu; Chen, Yingxu; Zhang, Zhijian; Tian, Guangming

    2008-01-01

    An undisturbed heavy clay soil column experiment was conducted to examine the influence of the new nitrification inhibitor, 3,4-dimethylpyrazole phosphate (DMPP), on nitrogen and soil salt-ion leaching. Regular urea was selected as the nitrogen source in the soil. The results showed that the cumulative leaching losses of soil nitrate-N under the treatment of urea with DMPP were from 57.5% to 63.3% lower than those of the treatment of urea without DMPP. The use of nitrification inhibitors as nitrate leaching retardants may be a proposal in regulations to prevent groundwater contaminant. However, there were no great difference between urea and urea with DMPP treatments on ammonium-N leaching. Moreover, the soil salt-ion leaching losses of Ca2+, Mg2+, K+, and Na+ were reduced from 26.6% to 28.8%, 21.3% to 27.8%, 33.3% to 35.5%, and 21.7% to 32.1%, respectively. So, the leaching losses of soil salt-ion were declined for nitrification inhibitor DMPP addition, being beneficial to shallow groundwater protection and growth of crop. These results indicated the possibility of ammonium or ammonium producing compounds using nitrification inhibitor DMPP to control the nitrate and nutrient cation leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.

  13. Plant diversity effects on leaching of nitrate, ammonium, and dissolved organic nitrogen from an experimental grassland

    NASA Astrophysics Data System (ADS)

    Leimer, Sophia; Oelmann, Yvonne; Wirth, Christian; Wilcke, Wolfgang

    2014-05-01

    Leaching of nitrogen (N) from soil represents a resource loss and, in particular leaching of nitrate, can threaten drinking water quality. As plant diversity leads to a more exhaustive resource use, we investigated the effects of plant species richness, functional group richness, and the presence of specific functional groups on nitrate, ammonium, dissolved organic N (DON), and total dissolved N (TDN) leaching from an experimental grassland in the first 4 years after conversion from fertilized arable land to unfertilized grassland. The experiment is located in Jena, Germany, and consists of 82 plots with 1, 2, 4, 8, 16, or 60 plant species and 1-4 functional groups (legumes, grasses, non-leguminous tall herbs, non-leguminous small herbs). Nitrate, ammonium, and TDN concentrations in soil solution in the 0-0.3 m soil layer were measured every second week during 4 years on 62 plots and DON concentrations were calculated as difference between TDN and inorganic N. Missing concentrations in soil solution were estimated using a Bayesian statistical model. Downward water fluxes (DF) per plot from the 0-0.3 m soil layer were simulated in weekly resolution with a water balance model in connection with a Bayesian model for simulating missing soil water content measurements. To obtain annual nitrate, ammonium, and DON leaching from the 0-0.3 m soil layer per plot, we multiplied the respective concentrations in soil solution with DF and aggregated the data to annual sums. TDN leaching resulted from summation of nitrate, ammonium, and DON leaching. DON leaching contributed most to TDN leaching, particularly in plots without legumes. Dissolved inorganic N leaching in this grassland was dominated by nitrate. The amount of annual ammonium leaching was small and little influenced by plant diversity. Species richness affected DON leaching only in the fourth and last investigated year, possibly because of a delayed soil biota effect that increased microbial transformation of organic

  14. Nitrate-Nitrogen Leaching and Modeling in Intensive Agriculture Farmland in China

    PubMed Central

    Xu, Ligang; Xu, Jin

    2013-01-01

    Protecting water resources from nitrate-nitrogen (NO3-N) contamination is an important public health concern and a major national environmental issue in China. Loss of NO3-N in soils due to leaching is not only one of the most important problems in agriculture farming, but is also the main factor causing nitrogen pollution in aquatic environments. Three typical intensive agriculture farmlands in Jiangyin City in China are selected as a case study for NO3-N leaching and modeling in the soil profile. In this study, the transport and fate of NO3-N within the soil profile and nitrate leaching to drains were analyzed by comparing field data with the simulation results of the LEACHM model. Comparisons between measured and simulated data indicated that the NO3-N concentrations in the soil and nitrate leaching to drains are controlled by the fertilizer practice, the initial conditions and the rainfall depth and distribution. Moreover, the study reveals that the LEACHM model gives a fair description of the NO3-N dynamics in the soil and subsurface drainage at the field scale. It can also be concluded that the model after calibration is a useful tool to optimize as a function of the combination “climate-crop-soil-bottom boundary condition” the nitrogen application strategy resulting for the environment in an acceptable level of nitrate leaching. The findings in this paper help to demonstrate the distribution and migration of nitrogen in intensive agriculture farmlands, as well as to explore the mechanism of groundwater contamination resulting from agricultural activities. PMID:23983629

  15. Longer thaw seasons increase nitrogen availability for leaching during fall in tundra soils

    NASA Astrophysics Data System (ADS)

    Treat, Claire C.; Wollheim, Wilfred M.; Varner, Ruth K.; Bowden, William B.

    2016-06-01

    Climate change has resulted in warmer soil temperatures, earlier spring thaw and later fall freeze-up, resulting in warmer soil temperatures and thawing of permafrost in tundra regions. While these changes in temperature metrics tend to lengthen the growing season for plants, light levels, especially in the fall, will continue to limit plant growth and nutrient uptake. We conducted a laboratory experiment using intact soil cores with and without vegetation from a tundra peatland to measure the effects of late freeze and early spring thaw on carbon dioxide (CO2) exchange, methane (CH4) emissions, dissolved organic carbon (DOC) and nitrogen (N) leaching from soils. We compared soil C exchange and N production with a 30 day longer seasonal thaw during a simulated annual cycle from spring thaw through freeze-up and thaw. Across all cores, fall N leaching accounted for ˜33% of total annual N loss despite significant increases in microbial biomass during this period. Nitrate ({{{{NO}}}3}-) leaching was highest during the fall (5.33 ± 1.45 mg N m-2 d-1) following plant senescence and lowest during the summer (0.43 ± 0.22 mg N m-2 d-1). In the late freeze and early thaw treatment, we found 25% higher total annual ecosystem respiration but no significant change in CH4 emissions or DOC loss due to high variability among samples. The late freeze period magnified N leaching and likely was derived from root turnover and microbial mineralization of soil organic matter coupled with little demand from plants or microbes. Large N leaching during the fall will affect N cycling in low-lying areas and streams and may alter terrestrial and aquatic ecosystem nitrogen budgets in the arctic.

  16. [Effects of elemental sulphur and dicyandiamide on mitigating NO3- -N leaching loss from vegetable soil].

    PubMed

    Zhao, Yanwen; Liu, Changzhen; Hu, Zhengyi; Gao, Yimin; Wang, Cairong; Bi, Dongmei

    2005-03-01

    In a pot experiment with allium as test plant and NH4HCO3 as nitrogen source, this paper studied the effects of element sulphur (S0) and dicyandiamide (DCD) on mitigating the NO3- -N leaching loss from soil and on soil inorganic nitrogen (NO3- -N and NH4+ -N) content. The results showed that within the 12 weeks of the experiment, the cumulative leaching loss of soil NO3- -N in treatments S0 + DCD and S0 was 83%-86% and 83% lower, while that of soil NH4+ -N was 16.8-21.0 mg x pot(-1) and 20.4-25.0 mg x pot(-1) higher than CK, respectively, and the cumulative loss of soil (NH4+ + NO3-)-N was 60% lower. By the end of the experiment, soil inorganic nitrogen content in treatments S0 + DCD and S0 was 79.9%-85.4% and 74.9-82.6% higher than CK, respectively. The cumulative leaching loss of inorganic N in treatment S0 + DCD was 4.6%-14.4% and 15.4%-30.1% lower, and the soil inorganic nitrogen content by the end of the experiment was 6.1% and 16.8%-36.0% higher than that of treatments S0 and DCD, respectively. Similar results were obtained when S0 was replaced by Na2S2O3, but not by Na2SO4. The fact that the application of S0 could obviously decrease the NO3- -N leaching loss from soil could be contributed to the inhibitory effects of S2O3(2-) and S4O6(2-) originated from S0 oxidation in soil on the nitrification of NH4+ -N. S0 could retard the decomposition of DCD due to the effect of its oxidized products S2O3(2-) and S4O6(2-), and thus, extend the inhibitory effect of DCD on NH4+ -N nitrification. It is suggested that S0 combined with DCD could be used as an effective nitrification inhibitor to control the NO3- -N leaching loss from vegetable soils.

  17. Phosphorus and nitrogen leaching before and after tillage and urea application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaching of nutrients through agricultural soils is a priority water quality concern on the Atlantic Coastal Plain. The objective of this study was to assess the effect of tillage on leaching of phosphorus (P) and nitrogen (N) from no-till soils of the Delmarva Peninsula, evaluating low and high nut...

  18. Nitrate leaching in a winter wheat-summer maize rotation on a calcareous soil as affected by nitrogen and straw management

    PubMed Central

    Huang, Tao; Ju, Xiaotang; Yang, Hao

    2017-01-01

    Nitrate leaching is one of the most important pathways of nitrogen (N) loss which leads to groundwater contamination or surface water eutrophication. Clarifying the rates, controlling factors and characteristics of nitrate leaching is the pre-requisite for proposing effective mitigation strategies. We investigated the effects of interactions among chemical N fertilizer, straw and manure applications on nitrogen leaching in an intensively managed calcareous Fluvo-aquic soil with winter wheat-summer maize cropping rotations on the North China Plain from October 2010 to September 2013 using ceramic suction cups and seepage water calculations based on a long-term field experiment. Annual nitrate leaching reached 38–60 kg N ha−1 from conventional N managements, but declined by 32–71% due to optimum N, compost manure or municipal waste treatments, respectively. Nitrate leaching concentrated in the summer maize season, and fewer leaching events with high amounts are the characteristics of nitrate leaching in this region. Overuse of chemical N fertilizers, high net mineralization and nitrification, together with predominance of rainfall in the summer season with light soil texture are the main controlling factors responsible for the high nitrate leaching loss in this soil-crop-climatic system. PMID:28176865

  19. Nitrate leaching in a winter wheat-summer maize rotation on a calcareous soil as affected by nitrogen and straw management

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Ju, Xiaotang; Yang, Hao

    2017-02-01

    Nitrate leaching is one of the most important pathways of nitrogen (N) loss which leads to groundwater contamination or surface water eutrophication. Clarifying the rates, controlling factors and characteristics of nitrate leaching is the pre-requisite for proposing effective mitigation strategies. We investigated the effects of interactions among chemical N fertilizer, straw and manure applications on nitrogen leaching in an intensively managed calcareous Fluvo-aquic soil with winter wheat-summer maize cropping rotations on the North China Plain from October 2010 to September 2013 using ceramic suction cups and seepage water calculations based on a long-term field experiment. Annual nitrate leaching reached 38–60 kg N ha‑1 from conventional N managements, but declined by 32–71% due to optimum N, compost manure or municipal waste treatments, respectively. Nitrate leaching concentrated in the summer maize season, and fewer leaching events with high amounts are the characteristics of nitrate leaching in this region. Overuse of chemical N fertilizers, high net mineralization and nitrification, together with predominance of rainfall in the summer season with light soil texture are the main controlling factors responsible for the high nitrate leaching loss in this soil-crop-climatic system.

  20. Effect of biochar on leaching of organic carbon, nitrogen, and phosphorus from compost in bioretention systems.

    PubMed

    Iqbal, Hamid; Garcia-Perez, Manuel; Flury, Markus

    2015-07-15

    Compost is used in bioretention systems to improve soil quality, water infiltration, and retention of contaminants. However, compost contains dissolved organic matter, nitrate, and phosphorus, all of which can leach out and potentially contaminate ground and surface waters. To reduce the leaching of nutrients and dissolved organic matter from compost, biochar may be mixed into the bioretention systems. Our objective was to test whether biochar and co-composted biochar mixed into mature compost can reduce the leaching of organic carbon, nitrogen, and phosphorus. There was no significant difference between the effects of biochar and co-composted biochar amendments on nutrient leaching. Further, biochar amendments did not significantly reduce the leaching of dissolved organic carbon, nitrate, and phosphorus as compared to the compost only treatment. The compost-sand mix was the most effective in reducing nitrate and phosphorus leaching among the media.

  1. Nitrogen loss during solar drying of biosolids.

    PubMed

    O'Shaughnessy, S A; Song, I; Artiola, J F; Choi, C Y

    2008-01-01

    Solar drying has been used extensively to dewater biosolids for ease of transportation and to a lesser degree to reduce pathogens prior to land application. The nitrogen in biosolids makes them a relatively inexpensive but valuable source of fertilizer. In this study, nitrogen loss from tilled and untilled biosolids was investigated during the solar drying process. Samples of aerobically and anaerobically digested biosolids during three solar drying experiments were analyzed for their nitrate (NO3-) and ammonium (NH4+) ions concentrations. Nitrogen losses varied depending on the solar drying season and tillage. Although not directly measured, the majority of nitrogen loss occurred through ammonia volatilization; organic nitrogen content (organic N) remained relatively stable for each sample, nitrate concentrations for the majority of samples remained below detectable levels and the decline of ammonium-nitrogen (NH4(+)-N) generally followed the trend of moisture loss in the biosolids.

  2. Influence of nitrogen loading and plant nitrogen assimilation on nitrogen leaching and N₂O emission in forage rice paddy fields fertilized with liquid cattle waste.

    PubMed

    Riya, Shohei; Zhou, Sheng; Kobara, Yuso; Sagehashi, Masaki; Terada, Akihiko; Hosomi, Masaaki

    2015-04-01

    Livestock wastewater disposal onto rice paddy fields is a cost- and labor-effective way to treat wastewater and cultivate rice crops. We evaluated the influence of nitrogen loading rates on nitrogen assimilation by rice plants and on nitrogen losses (leaching and N2O emission) in forage rice fields receiving liquid cattle waste (LCW). Four forage rice fields were subjected to nitrogen loads of 107, 258, 522, and 786 kg N ha(-1) (N100, N250, N500, and N750, respectively) using basal fertilizer (chemical fertilizer) (50 kg N ha(-1)) and three LCW topdressings (each 57-284 kg N ha(-1)). Nitrogen assimilated by rice plants increased over time. However, after the third topdressing, the nitrogen content of the biomass did not increase in any treatment. Harvested aboveground biomass contained 93, 60, 33, and 31 % of applied nitrogen in N100, N250, N500, and N750, respectively. The NH4 (+) concentration in the pore water at a depth of 20 cm was less than 1 mg N L(-1) in N100, N250, and N500 throughout the cultivation period, while the NH4 (+) concentration in N750 increased to 3 mg N L(-1) after the third topdressing. Cumulative N2O emissions ranged from -0.042 to 2.39 kg N ha(-1); the highest value was observed in N750, followed by N500. In N750, N2O emitted during the final drainage accounted for 80 % of cumulative N2O emissions. This study suggested that 100-258 kg N ha(-1) is a recommended nitrogen loading rate for nitrogen recovery by rice plants without negative environmental impacts such as groundwater pollution and N2O emission.

  3. A classification and regression tree model of controls on dissolved inorganic nitrogen leaching from European forests.

    PubMed

    Rothwell, James J; Futter, Martyn N; Dise, Nancy B

    2008-11-01

    Often, there is a non-linear relationship between atmospheric dissolved inorganic nitrogen (DIN) input and DIN leaching that is poorly captured by existing models. We present the first application of the non-parametric classification and regression tree approach to evaluate the key environmental drivers controlling DIN leaching from European forests. DIN leaching was classified as low (<3), medium (3-15) or high (>15kg N ha(-1) year(-1)) at 215 sites across Europe. The analysis identified throughfall NO(3)(-) deposition, acid deposition, hydrology, soil type, the carbon content of the soil, and the legacy of historic N deposition as the dominant drivers of DIN leaching for these forests. Ninety four percent of sites were successfully classified into the appropriate leaching category. This approach shows promise for understanding complex ecosystem responses to a wide range of anthropogenic stressors as well as an improved method for identifying risk and targeting pollution mitigation strategies in forest ecosystems.

  4. Quantifying nitrogen losses in oil palm plantations: models and challenges

    NASA Astrophysics Data System (ADS)

    Pardon, Lénaïc; Bessou, Cécile; Saint-Geours, Nathalie; Gabrielle, Benoît; Khasanah, Ni'matul; Caliman, Jean-Pierre; Nelson, Paul N.

    2016-09-01

    Oil palm is the most rapidly expanding tropical perennial crop. Its cultivation raises environmental concerns, notably related to the use of nitrogen (N) fertilisers and the associated pollution and greenhouse gas emissions. While numerous and diverse models exist to estimate N losses from agriculture, very few are currently available for tropical perennial crops. Moreover, there is a lack of critical analysis of their performance in the specific context of tropical perennial cropping systems. We assessed the capacity of 11 models and 29 sub-models to estimate N losses in a typical oil palm plantation over a 25-year growth cycle, through leaching and runoff, and emissions of NH3, N2, N2O, and NOx. Estimates of total N losses were very variable, ranging from 21 to 139 kg N ha-1 yr-1. On average, 31 % of the losses occurred during the first 3 years of the cycle. Nitrate leaching accounted for about 80 % of the losses. A comprehensive Morris sensitivity analysis showed the most influential variables to be soil clay content, rooting depth, and oil palm N uptake. We also compared model estimates with published field measurements. Many challenges remain in modelling processes related to the peculiarities of perennial tropical crop systems such as oil palm more accurately.

  5. Virtual Nitrogen Losses from Organic Food Production

    NASA Astrophysics Data System (ADS)

    Cattell Noll, L.; Galloway, J. N.; Leach, A. M.; Seufert, V.; Atwell, B.; Shade, J.

    2015-12-01

    Reactive nitrogen (Nr) is necessary for crop and animal production, but when it is lost to the environment, it creates a cascade of detrimental environmental impacts. The nitrogen challenge is to maximize the food production benefits of Nr, while minimizing losses to the environment. The first nitrogen footprint tool was created in 2012 to help consumers learn about the Nr losses to the environment that result from an individual's lifestyle choices. The nitrogen lost during food production was estimated with virtual nitrogen factors (VNFs) that quantify the amount of nitrogen lost to the environment per unit nitrogen consumed. Alternative agricultural systems, such as USDA certified organic farms, utilize practices that diverge from conventional production. In order to evaluate the potential sustainability of these alternative agricultural systems, our team calculated VNFs that reflect organic production. Initial data indicate that VNFs for organic grains and organic starchy roots are comparable to, but slightly higher than conventional (+10% and +20% respectively). In contrast, the VNF for organic vegetables is significantly higher (+90%) and the VNF for organic legumes is significantly lower (-90%). Initial data on organic meat production shows that organic poultry and organic pigmeat are comparable to conventional production (both <5% difference), but that the organic beef VNF is significantly higher (+30%). These data show that in some cases organic and conventional production are comparable in terms of nitrogen efficiency. However, since conventional production relies heavily on the creation of new reactive nitrogen (Haber-Bosch, biological nitrogen fixation) and organic production primarily utilizes already existing reactive nitrogen (manure, crop residue, compost), the data also show that organic production contributes less new reactive nitrogen to the environment than conventional production (approximately 70% less). Therefore, we conclude that on a local

  6. [Nitrate nitrogen leaching and residue of humic acid fertilizer in field soil].

    PubMed

    Liu, Fang-chun; Xing, Shang-jun; Duan, Chun-hua; Du, Zhen-yu; Ma, Hai-lin; Ma, Bing-yao

    2010-07-01

    To elucidate the potential influence of humic acidfertilizer on groundwater and soil quality in clay soil (CS) and sandy soil (SS), nitrate nitrogen leaching and residue of different fertilizers in field soil were studied using a self-made leaching field device. Nitrate nitrogen concentration in leaching water of fertilizer treatments was 28.1%-222.2% higher than that of non-nitrogen treatment in different times, but humic acid fertilizer could prevent nitrate nitrogen leaching both in CS and SS, especially in CS. Nitrate nitrogen concentration of leaching water in CS was 41.2%-59.1% less than that in SS and the inhibiting effect in CS was greater than that in SS. Nitrate nitrogen could be accumulated in soil profile by fertilizer application. The residue of nitrate nitrogen retained in 0-40 cm soil layer of humic acid fertilizer treatment was 59.8% and 54.4% respectively, higher than that of urea and compound fertilizer treatments. Nitrate nitrogen amount of humic acid, urea and compound fertilizer treatments in SS was significantly less than that in CS, being 81.7%, 81.1% and 47.6% respectively. Compared with the conventional fertilizer, humic acid fertilizer treatment improved the contents of organic matter, available nitrogen, phosphorus, and potassium of upper layer soil as well as cation exchange capacity. Besides, total amount of water-soluble salts in humic acid fertilizer treatment was decreased by 24.8% and 22.5% in comparison to urea and compound fertilizer treatments in CS, respectively. In summary, the application of humic acid fertilizer could improve physical and chemical properties of upper layer soil and reduce the risk of potential pollution to groundwater.

  7. Nitrate Leaching Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate (NO3) leaching is a significant nitrogen (N) loss process for agriculture that must be managed to minimize NO3 enrichment of groundwater and surface waters. Managing NO3 leaching should involve the application of basic principles of understanding the site’s hydrologic cycle, avoiding excess ...

  8. Nitrogen loss during solar drying of biosolids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solar drying has been used extensively to dewater biosolids for ease of transportation and to a lesser degree to reduce pathogens prior to land application. The nitrogen in biosolids makes it a relatively inexpensive but valuable source of fertilizer. In this study, nitrogen loss from tilled and unt...

  9. Surfactant-Modified Soil Amendments Reduce Nitrogen and Phosphorus Leaching in a Sand-Based Rootzone.

    PubMed

    Shaddox, Travis W; Kruse, Jason K; Miller, Grady L; Nkedi-Kizza, Peter; Sartain, Jerry B

    2016-09-01

    United States Golf Association putting greens are susceptible to nitrogen (N) and phosphorus (P) leaching. Inorganic soil amendments are used to increase moisture and nutrient retention and may influence N and P leaching. This study was conducted to determine whether N and P leaching could be reduced using soil amendments and surfactant-modified soil amendments. Treatments included a control (sand), sand-peat, zeolite, calcined clay, hexadecyltrimethylammonium-zeolite, and hexadecyltrimethylammonium-calcined clay. Lysimeters were filled with a 30-cm rootzone layer of sand-peat (85:15 by volume), below which a 5-cm treatment layer of amendments was placed. A solution of NO-N, NH-N, and orthophosphate-P (2300, 2480, and 4400 μg mL, respectively) was injected at the top of each lysimeter, and leachate was collected using an autocollector set to collect a 10-mL sample every min until four pore volumes were collected. Uncoated amendments, sand, and peat had no influence on NO-N retention, whereas hexadecyltrimethylammonium-coated amendments reduced NO-N leaching to below detectable limits. Both coated and uncoated amendments reduced NH-N leaching, with zeolite reducing NH-N leached to near zero regardless of hexadecyltrimethylammonium coating. Pure sand resulted in a 13% reduction of applied orthophosphate-P leaching, whereas peat contributed to orthophosphate-P leaching. Surfactant-modified amendments reduced orthophosphate-P leaching by as much as 97%. Surfactant-modified soil amendments can reduce NO-N, NH-N, and orthophosphate-P leaching and, thus, may be a viable option for removing leached N and P before they enter surface or ground waters.

  10. Pathways of nitrogen loss following land clearing in a humid tropical forest

    NASA Technical Reports Server (NTRS)

    Matson, Pamela; Vitousek, Peter

    1985-01-01

    Tropical deforestation generally leads to large losses of carbon and nitrogen. The Premontane Wet Forest Life Zone is subject to the highest rate of deforestation in Central America, and carbon and nutrient losses in from these fertile soils is very rapid and extreme. Losses of 2000 to 3000 kgN/ha have been reported. Losses of this magnitude could be extremely significant on a regional or global scale if even a small proportion of this nitrogen is lost as nitrous oxide to the atmosphere or through leaching of nitrate to rivers. This study seeks to measure the rates and regulation of nitrogen transformations, and the pathways of nitrogen losses following land clearing and burning at a site in the Premontane Wet Forest Life Zone near Turrialba, Costa Rica.

  11. Effects of polymer-coated urea on nitrate leaching and nitrogen uptake by potato.

    PubMed

    Wilson, Melissa L; Rosen, Carl J; Moncrief, John F

    2010-01-01

    Increasing groundwater nitrate concentrations in potato (Solanum tuberosum L.) production regions have prompted the need to identify alternative nitrogen management practices. A new type of polymer-coated urea (PCU) called Environmentally Smart Nitrogen (Agrium, Inc., Calgary, AB) is significantly lower in cost than comparable PCUs, but its potential to reduce nitrate leaching and improve fertilizer recovery has not been extensively studied in potato. In 2006 and 2007, four rates of PCU applied at emergence were compared with equivalent rates of soluble N split-applied at emergence and post-hilling. Additional treatments included a 0 N control, two PCU timing treatments (applied at preplant or planting), and a soluble N fertigation simulation. Nitrate leaching, fertilizer N recovery, N use efficiency (NUE), and residual soil inorganic N were measured. Both 2006 and 2007 were low leaching years. Nitrate leaching with PCU (21.3 kg NO(3)-N ha(-1) averaged over N rates) was significantly lower than with split-applied soluble N (26.9 kg NO(3)-N ha(-1)). The soluble N fertigation treatment resulted in similar leaching as PCU at equivalent N rates. Apparent fertilizer N recovery with PCU (65% averaged over four rates) tended to be higher than split-applied soluble N (55%) at equivalent rates (p = 0.059). Residual soil N and NUE were not significantly affected by N source. Under the conditions of this study, PCU significantly reduced leaching and tended to improved N recovery over soluble N applied in two applications and resulted in similar N recovery and nitrate leaching as soluble N applied in six applications.

  12. Predicting dissolved inorganic nitrogen leaching in European forests using two independent databases.

    PubMed

    Dise, N B; Rothwell, J J; Gauci, V; van der Salm, C; de Vries, W

    2009-02-15

    Regional-scale databases can be particularly useful for identifying relationships between dissolved inorganic nitrogen (N) leaching in forests and environmental drivers, which in turn allow an assessment of the risk of ecosystem damage, such as forest acidification and eutrophication of downstream water bodies. However, detecting the 'signal' of a significant correlate to N leaching against a background of wide variability in other factors requires a large number of sites, and the validation of models developed requires a similarly large number of independent sites. Here we use two large and fully independent databases of forest ecosystems across Europe to develop and validate indicators of N saturation and leaching. One database was used for model development and the other for validating these models. Among 35 variables considered, the most significant indicators of N leaching in the model development database were: the flux of dissolved inorganic N in deposition, mean annual temperature, mean altitude, the site drainage (plot vs catchment), needle- and litter-N concentration, organic horizon C:N ratio, and subsoil pH. Altitude was not a consistent predictor (it was significant in the development database but not in the validation database), and needle and litter N concentration, plot vs catchment, and subsoil pH all showed high intercorrelation with N deposition and so were not significant in models already including N deposition. The most consistent and useful indicators of N leaching were throughfall N deposition, organic horizon C:N ratio and mean annual temperature. Sites receiving low levels of N deposition (<8 kg N ha(-1) y(-1)) showed very low output fluxes of N and were simulated separately from more polluted forests. In general, the models successfully predicted N leaching (mean of +/-5 kg N ha(-1) y(-1) between observed and predicted) from forests at early to intermediate stages of nitrogen saturation but not from nitrogen-saturated sites. Thus, simple

  13. [Effects of different fertilizer species on carbon and nitrogen leaching in a reddish paddy soil].

    PubMed

    Liu, Xi-Yu; Zou, Jing-Dong; Xu, Li-Li; Zhang, Xin-Yu; Yang, Feng-Ting; Dai, Xiao-Qin; Wang, Zhong-Qiang; Sun, Xiao-Min

    2014-08-01

    Enhanced fertilization could decrease nitrogen utilization rate and increase carbon and nitrogen leaching, leading to water pollution in agricultural ecosystem. A long-term field experiment had been established on a reddish paddy soil of Qianyanzhou Ecological Experimental Station (114 degrees 53'E, 26 degrees 48'N) in Jiangxi Province in 1998. Soil solution samples were collected by clay tube and vacuum pump. Four fertilizer species treatments were selected: control with no fertilizer (CK), straw return (ST), nitrogen, phosphorus and potassium mineral fertilizers (NPK) and pig manure (OM), aiming to evaluate the effects of different species of fertilizer on carbon and nitrogen leaching in a double rice cropping system. The results showed that: (1) ammonium nitrogen (NH4(+) -N) was the major type of N in soil leachate in reddish paddy soil. The application of NPK could significantly increase the ammonium nitrogen concentration (1.2 mg x L(-1) +/- 0.1 mg x L(-1)) compared with the CK, ST and OM treatments, and the application of OM could significantly increase the dissolved organic carbon (DOC) concentration (27.3 mg x L(-1) +/- 1.6 mg x L(-1)) in soil leachate. The carbon and nitrogen leaching were more notable in the vegetative growth stage than the reproductive growth stage of rice (P < 0.05); (2) the long-term application of NPK and OM increased the NH4(+) -N, DOC, soil organic carbon (SOC) and total nitrogen (TN) contents. The NPK was best beneficial to improve TN contents and OM to improve SOC contents. (3) The DOC contents in soil leachate and SOC in paddy soil had a positive correlation (P < 0.01), while NH4(+) -N contents in soil leachate and TN contents in paddy soil had a positive correlation (P < 0.01).

  14. Impacts of Application of Methane Fermentation Digested Liquid on Green House Gas Emissions and Nitrogen Leaching from Upland Field

    NASA Astrophysics Data System (ADS)

    Nakamura, Masato; Fujikawa, Tomonori; Yuyama, Yoshito; Maeda, Morihiro; Yamaoka, Masaru

    Nitrogen uptake by crops, green-house gas emissions and nitrogen leaching were studied by using monolith lysimeters applied with digested liquid or ammonium sulfate to evaluate the environmental impacts of applications of methane fermentation digested liquid on Andosol upland field. A two-year experiment indicated the percentages of nitrogen uptake, leached nitrogen and nitrous oxide (N2O) emissions to each material-derived nitrogen were 27%, 44% and 0.41% in the digested liquid plot and 32%, 46% and 0.11% in the ammonium sulfate plot. The results show that digested liquid is readily release fertilizer like ammonium sulfate, and nitrogen is leached as easily from the digested liquid as from the ammonium sulfate and the N2O emissions from the digested liquid plot are higher than from the ammonium sulfate plot.

  15. Impact of anthropogenic induced nitrogen input and liming on phosphorous leaching in forest soils

    NASA Astrophysics Data System (ADS)

    Holzmann, Stefan; Puhlmann, Heike; Wilpert, Klaus

    2016-04-01

    Introduction: Phosphorous (P) is essential for sustainable forest growth, yet the impact of anthropogenic impacts on P leaching losses from forest soils are hardly known. Methods: We conducted an irrigation experiment with 128 mesocosms of 7.4 cm diameter containing 20 cm mineral soil plus the organic layer from three forest sites representing a gradient of resin extractable P of the A-horizon. On each site we selected a Fagus sylvatica and a Picea abies managed subsite. Half of the cylinders where planted with seedlings of the respective species to access the plant impact. We simulated ambient rain (AR), anthropogenic nitrogen input (NI) of 100 kg/ha/a and forest liming (FL) with a dolomite input of 0.3 Mg/ha/a. Soil solution was extracted from the organic layer and at 20 cm depth. We collected the soil solution over a period of 13.5 months and analyzed it separated by 5 periods. The soil solution was analyzed for total phosphorous (TP) by measuring the molybdane reactive phosphorous after acid digestion. To analyze the multivariate dataset we applied random forest modelling and used partial (co-)dependency plots to interpret the results. Results: The TP content of the soil solution from the organic horizon was approximately ten times higher than the soil solution content of the mineral soil. The NI treatment did increase the TP content on all sites. The increase was more pronounced in the organic layer than in the mineral layer. The FL treatment lead to a slight increase of TP in the organic layer while we could observe a slight decrease in the mineral horizon. Both the organic layer and the mineral horizon showed a seasonal cycle with the exception of one Picea abies subsite which displayed a constant increase in TP in the organic layer. The seasonal cycle of the organic horizon had a minimum during the period of April to July, while the minimum at the mineral horizon was during November to January. Conclusion: TP in the soil solution is highest in the organic

  16. Nitrogen fertilizer form and associated nitrate leaching from cool-season lawn turf.

    PubMed

    Guillard, Karl; Kopp, Kelly L

    2004-01-01

    Various N fertilizer sources are available for lawn turf. Few field studies, however, have determined the losses of nitrate (NO(3)-N) from lawns receiving different formulations of N fertilizers. The objectives of this study were to determine the differences in NO(3)-N leaching losses among various N fertilizer sources and to ascertain when losses were most likely to occur. The field experiment was set out in a completely random design on a turf typical of the lawns in southern New England. Treatments consisted of four fertilizer sources with fast- and slow-release N formulations: (i) ammonium nitrate (AN), (ii) polymer-coated sulfur-coated urea (PCSCU), (iii) organic product, and (iv) a nonfertilized control. The experiment was conducted across three years and fertilized to supply a total of 147 kg N ha(-1) yr(-1). Percolate was collected with zero-tension lysimeters. Flow-weighted NO(3)-N concentrations were 4.6, 0.57, 0.31, and 0.18 mg L(-1) for AN, PCSCU, organic, and the control, respectively. After correcting for control losses, average annual NO(3)-N leaching losses as a percentage of N applied were 16.8% for AN, 1.7% for PCSCU, and 0.6% for organic. Results indicate that NO(3)-N leaching losses from lawn turf in southern New England occur primarily during the late fall through the early spring. To reduce the threat of NO(3)-N leaching losses, lawn turf fertilizers should be formulated with a larger percentage of slow-release N than soluble N.

  17. Composting and gypsum amendment of broiler litter to reduce nutrient leaching loss.

    PubMed

    Adeli, Ardeshir; Sheng, J; Jenkins, J N; Feng, G

    2015-03-01

    The effect of composted litter relative to fresh litter on leaching losses of nutrients has not been well documented. Fresh and composted broiler litter was surface-applied to bermudagrass (hay) [ (L.) Pers.] established in undisturbed soil columns based on N need of the grass in the presence or absence of flue gas desulfurization (FGD) gypsum to evaluate an approach to reduce broiler litter nutrient leaching potential. Columns were periodically leached and biomass was harvested during the 60-d experiment. Total N applied to bermudagrass from broiler litter was 320 kg ha. Gypsum was mixed with fresh and composted litter at the rate based on 20% of litter weight. For composted broiler litter, NO-N, P, K, Cu, and Zn contents in the leachate obtained from the first leaching event were 58, 50, 40, 32, and 38% less than fresh broiler litter, respectively. Significant decreases in NO-N (13%), P (53%), Cu (17%), and Zn (28%) in leachate were obtained when gypsum was mixed with fresh broiler litter. Fresh broiler litter and composted broiler litter applications increased bermudagrass growth compared with the control and gypsum significantly increased yields when mixed with broiler litter. Composted broiler litter application significantly increased N and organic C in the soil compared with fresh litter. Results demonstrate that coapplication of composted broiler litter with FGD gypsum provide the most effective management option for minimizing leaching losses of nutrients while sustaining crop productivity.

  18. Composting and gypsum amendment of broiler litter to reduce nutrient leaching loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Relative to fresh broiler litter, little is known about the dynamics of composted litter derived-nutrient in the ecosystem. In this study, the potential leaching losses of nutrients from compost relative to fresh broiler litter along with flue gas desulfurization (FGD gypsum), as a nutrient immobil...

  19. Impacts of Future Land-Use Change on Nitrogen Leaching and Global Water Quality

    NASA Astrophysics Data System (ADS)

    Meiyappan, P.; Barman, R.; Jain, A. K.; McIsaac, G.; Lawrence, P.

    2011-12-01

    Agricultural expansion, excessive application of fertilizers, and increase in fossil fuel burning have led to widespread increases in anthropogenic production of reactive nitrogen (N), increasing N-deposition rates. An important consequence of these processes is intensification of soil nutrient leaching activities, leading to serious ground water and coastal water contamination problems. During the 21st century, projected land-use changes due to expansion of cropland surface are likely to significantly enhance anthropogenic soil N loading, intensifying nutrient leaching activities. Additionally, projected soil warming and increased fire disturbances in the high latitude forest ecosystems is also likely to increasingly mobilize soil N, and significantly contributing to the global leaching budget. In this study we employ a land surface model, the Integrated Science Assessment Model (ISAM), recently coupled to the NCAR Community Earth System Model (CESM1), to investigate the 21st century budget of soil N-leaching due to both anthropogenic and natural causes. ISAM (spatial resolution of 0.5ox0.5o) contains process based representation of prognostically coupled carbon-nitrogen cycles, and simulates all major N processes (immobilization, mineralization, nitrification, denitrification, leaching, biological fixation, and vegetation uptake). Biogeophysical schemes in the ISAM have been adapted from the NCAR Community Land Model (CLM3.5/CLM4) and the Common Land Model (CoLM), and fluxes of water and carbon are integrated at a time step of 30 minutes. ISAM incorporates land use change and secondary forest dynamics, to simulate the anthropogenic perturbation effects to the N cycle including atmospheric deposition and fertilizer application. Finally, the ISAM-CESM framework integrates a nutrient runoff tracer into the existing River Transport Model (RTM) in the CESM, enabling this study. In this talk, we will specifically focus on the results of a series of simulation

  20. Winter wheat starter nitrogen management: a preplant soil nitrate test and site specific nitrogen loss potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Managing highly variable residual nitrate-nitrogen (NO3-N) following corn (Zea mays L.) is difficult because it can supply starter nitrogen (N) for winter wheat (Triticum aestivum L.), and/or be leached into water resources during the fall-winter water-recharge season in the Humid East. A series of...

  1. Estimating reduction of nitrogen leaching from arable land and the related costs.

    PubMed

    Larsson, Martin H; Kyllmar, Katarina; Jonasson, Lars; Johnsson, Holger

    2005-11-01

    The EU Water Framework Directive will require river-basin management plans in order to achieve good ecological status and find the most cost-efficient nitrogen (N) leaching abatement measures. Detailed scenario calculations based on modeling methods will be valuable in this regard. This paper describes the approach and an application with a coefficient method based on the simulation model SOILNDB for quantification of N leaching from arable land and for prediction of the effect of abatement scenarios for the Rönneå catchment (1900 km2) in southern Sweden. Cost calculations for the different measures were also performed. The results indicate that the individual measures-cover crop and spring plowing, late termination of ley and fallow, and spring application of manure-would only reduce N leaching by between 5% and 8%. If all measures were combined and winter crops replaced by their corresponding spring variants, a 21% reduction in N leaching would be possible. However, this would require total fulfillment of the suggested measures.

  2. Nutrient leaching losses in lowland forests converted to oil palm and rubber plantations in Sumatra, Indonesia

    NASA Astrophysics Data System (ADS)

    Kurniawan, Syahrul; Corre, Marife D.; Rahayu Utami, Sri; Veldkamp, Edzo

    2015-04-01

    In the last two decades, Sumatra, Indonesia is experiencing rapid expansion of oil palm and rubber plantations by conversion of rainforest. This is evident from the 2.9 thousand km2 decrease in forest area in this region over the last 15 years. Such rapid land-use change necessitates assessment of its environmental impacts. Our study was aimed to assess the impact of forest conversion to oil palm and rubber plantations on nutrient leaching losses. Land-use conversion increases nutrient leaching losses due to changes in vegetation litter input, rooting depth, nutrient cycling and management (e.g. fertilization) practices. Our study area was in Jambi Province, Sumatra, Indonesia. We selected two soil landscapes in this region: loam and clay Acrisol soils. At each soil landscape, we investigated four land-use systems: lowland secondary rainforest, secondary forest with regenerating rubber (referred here as jungle rubber), rubber (7-17 years old) and oil palm plantations (9-16 years old). Each land use in each soil landscape was represented by four sites as replicates, totaling to 32 sites. We measured leaching losses using suction lysimeters installed at 1.5-m soil depth, which was well below the rooting depth, with bi-weekly to monthly sampling from February to December 2013. In general, the loam Acrisol landscape, particularly the forest and oil palm plantations, had lower soil solution pH and higher leaching fluxes of dissolved organic N, Na, Ca, Mg, total Al, total S and Cl than the clay Acrisol of the same land uses (all P ≤ 0.05). Among land uses in the loam Acrisol landscape, oil palm had lower soil solution pH and higher leaching fluxes of NH4+, NO3-, dissolved organic C, total P, total S and Cl than rubber plantation whereas forest and jungle rubber showed intermediate fluxes (all P ≤ 0.05, except P ≤ 0.09 for total P); oil palm had also higher Na, Ca, Mg and total Al leaching fluxes than all the other land uses (all P ≤ 0.05, except P ≤ 0.09 for Na

  3. [Effects of poplar-amaranth intercropping system on the soil nitrogen loss under different nitrogen applying levels].

    PubMed

    Chu, Jun; Xue, Jian-Hui; Wu, Dian-Ming; Jin, Mei-Juan; Wu, Yong-Bo

    2014-09-01

    Characteristics of soil nitrogen loss were investigated based on field experiments in two types of poplar-amaranth intercropping systems (spacing: L1 2 m x 5 m, L2 2 m x 15 m) with four N application rates, i. e., 0 (N1), 91 (N2), 137 (N3) and 183 (N4) kg · hm(-2). The regulation effects on the soil surface runoff, leaching loss and soil erosion were different among the different types of intercropping systems: L1 > L2 > L3 (amaranth monocropping). Compared with the amaranth monocropping, the soil surface runoff rates of L1 and L2 decreased by 65.1% and 55.9%, the soil leaching rates of L1 and L2 with a distance of 0.5 m from the poplar tree row de- creased by 30.0% and 28.9%, the rates with a distance of 1. 5 m decreased by 25. 6% and 21.9%, and the soil erosion rates decreased by 65.0% and 55.1%, respectively. The control effects of two intercropping systems on TN, NO(3-)-N and NH(4+)-N in soil runoff and leaching loss were in the order of L1 > L2 > L3. Compared with the amaranth monocropping, TN, NO(3-)-N and NH(4+)-N loss rates in soil runoff of L1 decreased by 62.9%, 45.1% and 69.2%, while the loss rates of L2 decreased by 23.4%, 6.9% and 46.2% under N1 (91 kg · hm(-2)), respectively. High- er tree-planting density and closer positions to the polar tree row were more effective on controlling the loss rates of NO(3-)-N and NH(4+)-N caused by soil leaching. The loss proportion of NO(3-)-N in soil runoff decreased with the increasing nitrogen rate under the same tree-planting density, while that of NH(4+)-N increased. Leaching loss of NO(3-)-N had a similar trend with that of NH(4+)-N, i. e. , N3 > N2 > N1 > N0.

  4. Nitrogen and phosphorus leaching from growing season versus year-round application of wastewater on seasonally frozen lands.

    PubMed

    Zvomuya, Francis; Rosen, Carl J; Gupta, Satish C

    2006-01-01

    Land application of wastewater has become an important disposal option for food-processing plants operating year-round. However, there are concerns about nutrient leaching from winter wastewater application on frozen soils. In this study, P and N leaching were compared between nongrowing season application of tertiary-treated wastewater plus growing season application of partially treated wastewater (NGS) vs. growing season application of partially treated wastewater (GS) containing high levels of soil P. As required by the Minnesota Pollution Control Agency (MPCA), the wastewater applied to the NGS fields during October through March was treated such that it contained < or =6 mg L(-1) total phosphorus (TP), < or =10 mg L(-1) NO3-N, and < or =20 mg L(-1) total Kjeldahl nitrogen (TKN). The only regulation for wastewater application during the growing season (April through September) was that cumulatively it did not exceed the agronomic N requirements of the crop in any sprayfield. Application of tertiary-treated wastewater during the nongrowing season plus partially treated wastewater during the growing season did not significantly increase NO3-N leaching compared with growing season application of nonregulated wastewater. However, median TP concentration in leachate was significantly higher from the NGS (3.56 mg L(-1)) than from the GS sprayfields (0.52 mg L(-1)) or nonirrigated sites (0.52 mg L(-1)). Median TP leaching loss was also significantly higher from the NGS sprayfields (57 kg ha(-1)) than from the GS (7.4 kg ha(-1)) or control sites (6.9 kg ha(-1)). This was mainly due to higher hydraulic loading from winter wastewater application and limited or no crop P uptake during winter. Results from this study indicate that winter application of even low P potato-processing wastewater to high P soils can accelerate P leaching. We conclude that the regulation of winter wastewater application on frozen soils should be based on wastewater P concentration and

  5. Abiotic gas formation drives nitrogen loss from a desert ecosystem.

    PubMed

    McCalley, Carmody K; Sparks, Jed P

    2009-11-06

    In arid environments such as deserts, nitrogen is often the most limiting nutrient for biological activity. The majority of the ecosystem nitrogen flux is typically thought to be driven by production and loss of reactive nitrogen species by microorganisms in the soil. We found that high soil-surface temperatures (greater than 50 degrees C), driven by solar radiation, are the primary cause of nitrogen loss in Mojave Desert soils. This abiotic pathway not only enables the balancing of arid ecosystem nitrogen budgets, but also changes our view of global nitrogen cycling and the predicted impact of climate change and increased temperatures on nitrogen bioavailability.

  6. [Effects of seeding-box total fertilization on rice yield and nitrogen loss].

    PubMed

    Liu, Ru-Liang; Li, You-Hong; Zhang, Ai-Ping; Wang, Fang; Zhao, Tian-Cheng; Chen, Chen; Hong, Yu; Yang, Zheng-Li

    2012-07-01

    By using seeding-box total fertilization technology, a two-year field plot experiment was conducted to study the effects of applying medium rate of controlled-release urea fertilizer (MN, 80 kg N x hm(-2)), high rate of controlled-release urea fertilizer (HN, 120 kg N x hm(-2)), and conventional urea fertilizer (FP, 300 kg N x hm(-2)) on rice yield and nitrogen loss. As compared with FP, HN did not decrease rice yield significantly, and MN and HN increased the two-year average nitrogen use efficiency (NUE) by 26.2% and 20.7%, respectively (the NUE in treatment FP was 33.2%). In treatment FP, the total N concentration in surface water peaked after 1-3 days of urea application; while in treatments MN and HN, the total N concentration in surfate water peaked after 7-9 days of urea application, and was significantly lower than that in treatment FP throughout the rice growth period. The nitrogen leaching loss in treatment FP mainly occurred at tillering stage, while that in treatments MN and HN delayed to tillering-flowering stage. In all treatments, the NO3(-)-N loss accounted for 59.7% - 64.2% of the total N loss. HN decreased the total N leaching loss by 51.8%, as compared with FP.

  7. Effect of application of dairy manure, effluent and inorganic fertilizer on nitrogen leaching in clayey fluvo-aquic soil: A lysimeter study.

    PubMed

    Fan, Jianling; Xiao, Jiao; Liu, Deyan; Ye, Guiping; Luo, Jiafa; Houlbrooke, David; Laurenson, Seth; Yan, Jing; Chen, Lvjun; Tian, Jinping; Ding, Weixin

    2017-08-15

    Dairy farm manure and effluent are applied to cropland in China to provide a source of plant nutrients, but there are concerns over its effect on nitrogen (N) leaching loss and groundwater quality. To investigate the effects of land application of dairy manure and effluent on potential N leaching loss, two lysimeter trials were set up in clayey fluvo-aquic soil in a winter wheat-summer maize rotation cropping system on the North China Plain. The solid dairy manure trial included control without N fertilization (CK), inorganic N fertilizer (SNPK), and fresh (RAW) and composted (COM) dairy manure. The liquid dairy effluent trial consisted of control without N fertilization (CF), inorganic N fertilizer (ENPK), and fresh (FDE) and stored (SDE) dairy effluent. The N application rate was 225kgNha(-1) for inorganic N fertilizer, dairy manure, and effluent treatments in both seasons. Annual N leaching loss (ANLL) was highest in SNPK (53.02 and 16.21kgNha(-1) in 2013/2014 and 2014/2015, respectively), which were 1.65- and 2.04-fold that of COM, and 1.59- and 1.26-fold that of RAW. In the effluent trial (2014/2015), ANLL for ENPK and SDE (16.22 and 16.86kgNha(-1), respectively) were significantly higher than CF and FDE (6.3 and 13.21kgNha(-1), respectively). NO3(-) contributed the most (34-92%) to total N leaching loss among all treatments, followed by dissolved organic N (14-57%). COM showed the lowest N leaching loss due to a reduction in NO3(-) loss. Yield-scaled N leaching in COM (0.35kgNMg(-1) silage) was significantly (P<0.05) lower than that in the other fertilization treatments. Therefore, the use of composted dairy manure should be increased and that of inorganic fertilizer decreased to reduce N leaching loss while ensuring high crop yield in the North China Plain.

  8. Response of maize yield, nitrate leaching, and soil nitrogen to pig slurry combined with mineral nitrogen.

    PubMed

    Yagüe, María R; Quílez, Dolores

    2010-01-01

    The application of pig (Sus scrofa) slurry (PS) is a common fertilization practice that may affect nitrate concentrations and loads in drainage and receiving water bodies. To protect water resources, many agricultural areas are being designated as vulnerable to nitrate contamination, and there is a need for scientific data aiming at reducing nitrate exports from these vulnerable zones by optimizing N fertilization strategies. The objective of this work, conducted in drainage lysimeters in a 4-yr monoculture maize (Zea mays L.) crop, is to assess the effects of four fertilization strategies combining PS (30, 60, 90, and 120 t ha(-1)) and mineral N on yield, changes in soil mineral N, and concentration and mass of nitrate in drainage waters. Grain yield was not affected by treatments in the four experimental years, nor was the soil mineral N at the end of the experiment. Effects of fertilization strategies on nitrate concentration and mass in drainage waters were detected only after 3 yr of repeated PS applications. The mass of nitrate leached over the 4 yr was positively related to the total amount of N applied, either organic or mineral. In year 2003, precipitation in spring reduced N availability for the crop in treatments with rates > or = 60 t PS ha(-1). The N-budget revealed that the transport pathways for 25% of N inputs to the system are unknown. The presowing application of pig slurry at 30 t ha(-1) complemented with mineral N at side-dressing, was the most efficient from an environmental standpoint (4-yr average of 145 kg grain yield kg(-1) N leached).

  9. Nitrogen removal and nitrate leaching for two perennial, sod-based forage systems receiving dairy effluent.

    PubMed

    Woodard, Kenneth R; French, Edwin C; Sweat, Lewin A; Graetz, Donald A; Sollenberger, Lynn E; Macoon, Bisoondat; Portier, Kenneth M; Rymph, Stuart J; Wade, Brett L; Prine, Gordon M; Van Horn, Harold H

    2003-01-01

    In northern Florida, year-round forage systems are used in dairy effluent sprayfields to reduce nitrate leaching. Our purpose was to quantify forage N removal and monitor nitrate N (NO3(-)-N) concentration below the rooting zone for two perennial, sod-based, triple-cropping systems over four 12-mo cycles (1996-2000). The soil is an excessively drained Kershaw sand (thermic, uncoated Typic Quartzip-samment). Effluent N rates were 500, 690, and 910 kg ha(-1) per cycle. Differences in N removal between a corn (Zea mays L.)-bermudagrass (Cynodon spp.)-rye (Secale cereale L.) system (CBR) and corn-perennial peanut (Arachis glabrata Benth.)-rye system (CPR) were primarily related to the performance of the perennial forages. Nitrogen removal of corn (125-170 kg ha(-1)) and rye (62-90 kg ha(-1)) was relatively stable between systems and among cycles. The greatest N removal was measured for CBR in the first cycle (408 kg ha(-1)), with the bermudagrass removing an average of 191 kg N ha(-1). In later cycles, N removal for bermudagrass declined because dry matter (DM) yield declined. Yield and N removal of perennial peanut increased over the four cycles. Nitrate N concentrations below the rooting zone were lower for CBR than CPR in the first two cycles, but differences were inconsistent in the latter two. The CBR system maintained low NO3(-)-N leaching in the first cycle when the bermudagrass was the most productive; however, it was not a sustainable system for long-term prevention of NO3(-)-N leaching due to declining bermudagrass yield in subsequent cycles. For CPR, effluent N rates > or = 500 kg ha(-1) yr(-1) have the potential to negatively affect ground water quality.

  10. After the Storm: Assessing the carbon and nitrogen leaching potential from sediments deposited in aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Johnson, E. R.; Krieg, C.; Canning, C.; Inamdar, S. P.; Rowland, R. D.

    2015-12-01

    The erosive energy of large storms can mobilize, and subsequently deposit large amounts of sediment in receiving aquatic ecosystems. Depending on the character of the sediments there is potential for leaching or sequestration of carbon (C) and nitrogen (N) from the sediments. This could have significant implications for water quality, aquatic metabolism, and global cycling of C and N. This study examines the fate of these sediments by: (1) determining the amount and quality of organic matter that can be leached into the surrounding water from coarse, medium and fine particle classes (2) assessing the C and N contents of various particles classes and the sources of the sediment through isotopic composition. Bed sediment samples were collected along a 1-2nd order stream (eight locations) in a forested catchment in the Piedmont region of Maryland following a large storm event. Samples were sieved into three particle classes - coarse (2mm-1mm), medium (1mm-250µm) and fine (<250µm). Extractions were performed for each of three particle class sizes by leaching with DI water. Organic matter composition for the extracts was characterized using fluorescence. Stable isotopes of 13C and 15N were determined for bed sediment classes and upland source sediments to identify the origins of the eroded sediments. Extracts with low C:N ratios that also exhibit a higher percent protein and lower percent humic carbon content are considered most labile. Within the bed sediment deposits, differences were found in the distribution of labile compounds between each particle class size. Generally, course particle size exhibited the most labile characteristics, closely followed by medium particle size. Fine particle size exhibited the most refractory characteristics in all locations. These results are critical since climate-change predictions reveal more intense and large storms for the northeast US, with potentially greater impacts on aquatic ecosystems from eroded upland sediments.

  11. [Evaluation of nitrogen loss way in summer maize system under different fertilizer N managements].

    PubMed

    Lin, Li; Hu, Ke-Lin; Li, Guang-De; Wang, Huan-Yuan

    2011-09-01

    The objective of this study was to investigate nitrogen (N) loss from soil-crop systems under different fertilizer N managements, and to provide some suggestions on optimizing fertilizer management practices. The experiment was carried in high yield production area of Huantai county in Shandong province in 2009. Four kinds of fertilizer N application practices were designed, including CK, farmer practice (FP), optimizing fertilizer application (OPT) and controlled release fertilizer (CRT) for studying the fate of N during the maize growth season in 2009. The water and nitrogen management model (WNMM) was used to simulate the dynamics of soil water and N fate. The results indicated that the ratio of nitrate leaching and NH3 volatilization accounting of fertilizer N ranged from 6% to 18% and 5% to 34%, and their means were 12.7% and 20.7%, respectively. The amount of N leaching under OPT was 14.5 kg x hm(-2), was the lowest in all treatments. The amount of NH3 volatilization under CRT was 7.6 kg x hm(-2), respectively, was the lowest in all treatments. The order of total N loss under four treatments followed as: FP > OPT > CRF approximately CK. Both OPT and CRT treatments are the best management practices considering their high grain yield, water and nitrogen use efficiencies, and environmental protection.

  12. Nitrogen availability and leaching from soil amended with municipal solid waste compost

    SciTech Connect

    Mamo, M.; Rosen, C.J.; Halbach, T.R.

    1999-08-01

    Beneficial use of municipal solid waste compost depends on identifying a management strategy that supports crop production and protects water quality. Effects of compost and N fertilizer management strategies on corn (Zea mays L.) yield and NO{sub 3}{sup {minus}}-N leaching were evaluated in a 3-yr study on a Hubbard loamy sand soil. Two composts were each applied at either 90 Mg ha{sup {minus}1} yr{sup {minus}1} from 1993 to 1995, or at 270 Mg ha{sup {minus}1} in one application in 1993. The compost and non-amended plots were side dressed annually with N fertilizer as urea at 0, 125, and 250 kg ha{sup {minus}1}. Biochemical properties of the compost as well as compost management strongly affected crop response and fate of N. Compost increased grain yield with no significant yield response to N fertilizer with the single compost application in Year 1 and the annual compost application in Year 3. Plant N uptake increased with N fertilizer rate, except in the 270 Mg ha{sup {minus}1} compost treatments in Year 1. Over the 3-yr period, NO{sub 3}{sup {minus}}-N leaching with the 270 Mg ha{sup {minus}1} compost application was 1.8 times greater compared to that with the annual application. The estimated N mineralization ranged from 0 to 12% and 3 to 6% in the annual and single compost addition, respectively. Under the conditions of this study, annual compost application with reduced supplemental N fertilizer was the best management strategy to reach optimum crop yield while minimizing NO{sub 3}{sup {minus}}-N leaching losses.

  13. Effect of nitrification inhibitor DMPP on nitrogen leaching, nitrifying organisms, and enzyme activities in a rice-oilseed rape cropping system.

    PubMed

    Li, Hua; Liang, Xinqiang; Chen, Yingxu; Lian, Yanfeng; Tian, Guangming; Ni, Wuzhong

    2008-01-01

    DMPP (3,4-dimethylpyrazole phosphate) has been used to reduce nitrogen (N) loss from leaching or denitrification and to improve N supply in agricultural land. However, its impact on soil nitrifying organisms and enzyme activities involved in N cycling is largely unknown. Therefore, an on-farm experiment, for two years, has been conducted, to elucidate the effects of DMPP on mineral N (NH4(+)-N and NO3(-)-N) leaching, nitrifying organisms, and denitrifying enzymes in a rice-oilseed rape cropping system. Three treatments including urea alone (UA), urea + 1% DMPP (DP), and no fertilizer (CK), have been carried out. The results showed that DP enhanced the mean NH4(+)-N concentrations by 19.1%--24.3%, but reduced the mean NO3(-)-N concentrations by 44.9%--56.6% in the leachate, under a two-year rice-rape rotation, compared to the UA treatment. The population of ammonia oxidizing bacteria, the activity of nitrate reductase, and nitrite reductase in the DP treatment decreased about 24.5%--30.9%, 14.9%--43.5%, and 14.7%--31.6%, respectively, as compared to the UA treatment. However, nitrite oxidizing bacteria and hydroxylamine reductase remained almost unaffected by DMPP. It is proposed that DMPP has the potential to either reduce NO3(-)-N leaching by inhibiting ammonia oxidization or N losses from denitrification, which is in favor of the N conversations in the rice-oilseed rape cropping system.

  14. Stabilized nitrogen fertilizers and application rate influence nitrogen losses under rainfed spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) losses associated with fertilizer application have negative economic and environmental consequences, but urease and nitrification inhibitors have potential to reduce N losses. The effectiveness of these inhibitors has been studied extensively in irrigated but not rainfed systems. Theref...

  15. Quantifying and characterizing dissolved carbon and nitrogen leaching from litter: a comparison of methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Litter decomposition has a fundamental role in ecosystem functioning. It recycles energy, carbon and nutrients, supporting ecosystem productivity and soil organic matter formation. Litter decomposition occurs through leaching, fragmentation, and catabolism. Leaching is, arguably, the least studie...

  16. Identifying critical nitrogen application rate for maize yield and nitrate leaching in a Haplic Luvisol soil using the DNDC model.

    PubMed

    Zhang, Yitao; Wang, Hongyuan; Liu, Shen; Lei, Qiuliang; Liu, Jian; He, Jianqiang; Zhai, Limei; Ren, Tianzhi; Liu, Hongbin

    2015-05-01

    Identification of critical nitrogen (N) application rate can provide management supports for ensuring grain yield and reducing amount of nitrate leaching to ground water. A five-year (2008-2012) field lysimeter (1 m × 2 m × 1.2 m) experiment with three N treatments (0, 180 and 240 kg Nha(-1)) was conducted to quantify maize yields and amount of nitrate leaching from a Haplic Luvisol soil in the North China Plain. The experimental data were used to calibrate and validate the process-based model of Denitrification-Decomposition (DNDC). After this, the model was used to simulate maize yield production and amount of nitrate leaching under a series of N application rates and to identify critical N application rate based on acceptable yield and amount of nitrate leaching for this cropping system. The results of model calibration and validation indicated that the model could correctly simulate maize yield and amount of nitrate leaching, with satisfactory values of RMSE-observation standard deviation ratio, model efficiency and determination coefficient. The model simulations confirmed the measurements that N application increased maize yield compared with the control, but the high N rate (240 kg Nha(-1)) did not produce more yield than the low one (120 kg Nha(-1)), and that the amount of nitrate leaching increased with increasing N application rate. The simulation results suggested that the optimal N application rate was in a range between 150 and 240 kg ha(-1), which would keep the amount of nitrate leaching below 18.4 kg NO₃(-)-Nha(-1) and meanwhile maintain acceptable maize yield above 9410 kg ha(-1). Furthermore, 180 kg Nha(-1) produced the highest yields (9837 kg ha(-1)) and comparatively lower amount of nitrate leaching (10.0 kg NO₃(-)-Nha(-1)). This study will provide a valuable reference for determining optimal N application rate (or range) in other crop systems and regions in China.

  17. Quantifying climate and management effects on regional crop yield and nitrogen leaching in the north china plain.

    PubMed

    Fang, Q X; Ma, L; Yu, Q; Hu, C S; Li, X X; Malone, R W; Ahuja, L R

    2013-09-01

    Better water and nitrogen (N) management requires better understanding of soil water and N balances and their effects on crop yield under various climate and soil conditions. In this study, the calibrated Root Zone Water Quality Model (RZWQM2) was used to assess crop yield and N leaching under current and alternative management practices in a double-cropped wheat ( L.) and maize ( L.) system under long-term weather conditions (1970-2009) for dominant soil types at 15 locations in the North China Plain. The results provided quantitative long-term variation of deep seepage and N leaching at these locations, which strengthened the existing qualitative knowledge for site-specific management of water and N. In general, the current management practices showed high residual soil N and N leaching in the region, with the amounts varying between crops and from location to location and from year to year. Seasonal rainfall explained 39 to 84% of the variability in N leaching (1970-2009) in maize across locations, while for wheat, its relationship with N leaching was significant ( < 0.01) only at five locations. When N and/or irrigation inputs were reduced to 40 to 80% of their current levels, N leaching generally responded more to N rate than to irrigation, while the reverse was true for crop yield at most locations. Matching N input with crop requirements under limited water conditions helped achieve lower N leaching without considerable soil N accumulation. Based on the long-term simulation results and water resources availability in the region, it is recommended to irrigate at 60 to 80% of the current water levels and fertilize only at 40 to 60% of the current N rate to minimizing N leaching without compromising crop yield.

  18. Nitrogen inputs and losses in response to chronic CO2 exposure in a subtropical oak woodland

    NASA Astrophysics Data System (ADS)

    Hungate, B. A.; Duval, B. D.; Dijkstra, P.; Johnson, D. W.; Ketterer, M. E.; Stiling, P.; Cheng, W.; Millman, J.; Hartley, A.; Stover, D. B.

    2014-06-01

    Rising atmospheric CO2 concentrations may alter the nitrogen (N) content of ecosystems by changing N inputs and N losses, but responses vary in field experiments, possibly because multiple mechanisms are at play. We measured N fixation and N losses in a subtropical oak woodland exposed to 11 years of elevated atmospheric CO2 concentrations. We also explored the role of herbivory, carbon limitation, and competition for light or nutrients in shaping the response of N fixation to elevated CO2. Elevated CO2 did not significantly alter gaseous N losses, but lower recovery and deeper distribution in the soil of a long-term 15N tracer indicated that elevated CO2 increased leaching losses. Elevated CO2 had no effect on nonsymbiotic N fixation, and had a transient effect on symbiotic N fixation by the dominant legume. Elevated CO2 tended to reduce soil and plant concentrations of iron, molybdenum, phosphorus, and vanadium, nutrients essential for N fixation. Competition for nutrients and herbivory likely contributed to the declining response of N fixation to elevated CO2. These results indicate that positive responses of N fixation to elevated CO2 may be transient and that chronic exposure to elevated CO2 can increase N leaching. Models that assume increased fixation or reduced N losses with elevated CO2 may overestimate future N accumulation in the biosphere.

  19. Adaptive Management Tools for Nitrogen: Nitrogen Index, Nitrogen Trading Tool and Nitrogen Losses Environmental Assessment Package (NLEAP-GIS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Average nitrogen (N) use efficiencies are approximately fifty percent and can be even lower for shallower rooted systems grown on irrigated sandy soils. These low N use efficiencies need to be increased if reactive N losses to the environmental are to be reduced. Recently, USDA-NRCS identified Adapt...

  20. Temporal patterns and source apportionment of nitrate-nitrogen leaching in a paddy field at Kelantan, Malaysia.

    PubMed

    Hussain, Hazilia; Yusoff, Mohd Kamil; Ramli, Mohd Firuz; Abd Latif, Puziah; Juahir, Hafizan; Zawawi, Mohamed Azwan Mohammed

    2013-11-15

    Nitrate-nitrogen leaching from agricultural areas is a major cause for groundwater pollution. Polluted groundwater with high levels of nitrate is hazardous and cause adverse health effects. Human consumption of water with elevated levels of NO3-N has been linked to the infant disorder methemoglobinemia and also to non-Hodgkin's disease lymphoma in adults. This research aims to study the temporal patterns and source apportionment of nitrate-nitrogen leaching in a paddy soil at Ladang Merdeka Ismail Mulong in Kelantan, Malaysia. The complex data matrix (128 x 16) of nitrate-nitrogen parameters was subjected to multivariate analysis mainly Principal Component Analysis (PCA) and Discriminant Analysis (DA). PCA extracted four principal components from this data set which explained 86.4% of the total variance. The most important contributors were soil physical properties confirmed using Alyuda Forecaster software (R2 = 0.98). Discriminant analysis was used to evaluate the temporal variation in soil nitrate-nitrogen on leaching process. Discriminant analysis gave four parameters (hydraulic head, evapotranspiration, rainfall and temperature) contributing more than 98% correct assignments in temporal analysis. DA allowed reduction in dimensionality of the large data set which defines the four operating parameters most efficient and economical to be monitored for temporal variations. This knowledge is important so as to protect the precious groundwater from contamination with nitrate.

  1. Modeling nitrate leaching and optimizing water and nitrogen management under irrigated maize in desert oases in Northwestern China.

    PubMed

    Hu, Kelin; Li, Yong; Chen, Weiping; Chen, Deli; Wei, Yongping; Edis, Robert; Li, Baoguo; Huang, Yuanfang; Zhang, Yuanpei

    2010-01-01

    Understanding water and N transport through the soil profile is important for efficient irrigation and nutrient management to minimize nitrate leaching to the groundwater, and to promote agricultural sustainable development in desert oases. In this study, a process-based water and nitrogen management model (WNMM) was used to simulate soil water movement, nitrate transport, and crop growth (maize [Zea mays L.]) under desert oasis conditions in northwestern China. The model was calibrated and validated with a field experiment. The model simulation results showed that about 35% of total water input and 58% of the total N input were leached to <1.8 m depth under traditional management practice. Excessive irrigation and N fertilizer application, high nitrate concentration in the irrigation water, together with the sandy soil texture, resulted in large nitrate leaching. Nitrate leaching was significantly reduced under the improved management practice suggested by farm extension personnel; however, the water and nitrate inputs still far exceeded the crop requirements. More than 1700 scenarios combining various types of irrigation and fertilizer practices were simulated. Quantitative analysis was conducted to obtain the best management practices (BMPs) with simultaneous consideration of crop yield, water use efficiency, fertilizer N use efficiency, and nitrate leaching. The results indicated that the BMPs under the specific desert oasis conditions are to irrigate the maize with 600 mm of water in eight times with a single fertilizer application at a rate of 75 kg N ha(-1).

  2. Controls on Nitrogen Retention and Loss in Urban and Rural Forest Ecosystems.

    NASA Astrophysics Data System (ADS)

    Templer, P. H.

    2011-12-01

    Human activities, such as the burning of fossil fuels and production of fertilizer, have increased the amount of nitrogen deposited onto terrestrial ecosystems. In addition to changes in atmospheric deposition of nitrogen, other human-induced disturbances have led to dramatic shifts in forest composition of the United States over the last 100 years. Tree species composition of many forests is changing in response to introduced pests and pathogens, competition with introduced plant species and changes in climate. Understanding the combined effects of increased nitrogen inputs and changes in plant species composition on forest nitrogen cycling is critical to our understanding of forest biogeochemistry and nutrient budgets. Despite several decades of research on the effects of atmospheric nitrogen deposition, there is still significant uncertainty about the factors that regulate nitrogen retention and loss in forest ecosystems. The use of natural abundance stable isotopes of nitrogen and oxygen has proven to be a powerful tool for tracing the sources of nitrate in water, from inputs to leaching, as it moves through an ecosystem. The evaluation of natural abundance nitrogen values in atmospheric deposition has been used to partition sources of nitrogen, such as coal-fired power plants vs. tailpipe exhaust, since each of their isotopic signatures is distinct. Similarly, natural abundance oxygen values of nitrate in atmospheric inputs and soil leachate have been used as a tool to partition sources of nitrate between precipitation and nitrate produced microbially during nitrification. We measured the natural abundance isotopic composition of nitrate to quantify rates of nitrogen inputs to the forest and to determine rates of nitrogen losses from healthy, declining and preemptively cut eastern hemlock (Tsuga canadensis) stands in both an urban forest at the Arnold Arboretum in Boston, MA, and a rural forest at Harvard Forest in Petersham, MA. The hemlock woolly adelgid

  3. Phosphorus and nitrogen losses from winter stacking of manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Appropriate management of animal manure including storage is essential for minimizing nutrient losses and guaranteeing good water quality. A field lysimeter study was carried out at the Susquehanna River Basin, northeastern USA to investigate phosphorus (P) and nitrogen (N) losses in leachate and ru...

  4. Nitrogen loss from sprinkler applied beef feedlot effluent

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Loss of nitrogen from sprinkler applied beef feedlot effluent can be costly for both the producer and the environment. Sprinkler application of effluent is common throughout the Great Plains, though little work has occurred focusing specifically on N losses from beef feedlot effluent. The objectives...

  5. Nitrogen Index

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a need to improve the management of nitrogen inputs to agricultural systems because they increase the potential for losses of reactive nitrogen to the environment, resulting in negative impacts to water and air resources. There is a need to reduce nitrate leaching, emissions of N2O from agr...

  6. INDICATORS OF NITRATE LEACHING LOSS UNDER DIFFERENT LAND USE OF CLAYEY AND SANDY SOILS IN SOUTHEASTERN OKLAHOMA

    EPA Science Inventory

    Evidence of increasing nitrate (NO3-) leaching losses from soils under various land use systems has elevated the interest and need to find better land management practices. An essential step in developing new management practices is understanding of the com...

  7. Effects of improving nitrogen management on nitrogen utilization, nitrogen balance, and reactive nitrogen losses in a Mollisol with maize monoculture in Northeast China.

    PubMed

    Yan, Li; Zhang, Zhi-Dan; Zhang, Jin-Jing; Gao, Qiang; Feng, Guo-Zhong; Abelrahman, A M; Chen, Yuan

    2016-03-01

    Traditional fertilization led to higher apparent N surplus, and optimized fertilization can reduce residual nitrogen in soils with keeping high yield. But in continuous spring maize cropping zone in Mollisol in Northeast China, the effect of the optimized N management on N balance and comprehensive environment was not clear. The primary objective of this study was to compare the differences of two fertilizations (traditional farmer N management (FNM) with single basal fertilizer and improvement N management (INM) by soil testing with top-dressing) in gain yield, N uptake and N efficiency, soil N balance, reactive N losses, and environment assessment. The results showed that INM treatment has no remarkable effect on grain yield and N uptake; N partial factor productivity (PFPN) of INM treatment was 19.8 % significantly higher than the FNM treatment. Nmin in soils of INM treatment reached to 111.0 kg ha(-1), which was 27.1 % lower than the FNM treatment after 6 years of continuous maize cropping; the apparent N Losses (ANL) and apparent N surplus (ANS) of INM were only half of FNM by soil N balance analysis. In reactive N losses, comparing with FNM treatment, INM treatment reduced NH3 volatilization, N2O emission, N leaching, and N runoff by 17.8, 35.6, 45, and 38.3 %, respectively, during planting period, and in integrated environment assessment by life cycle assessment (LCA) method, producing 1 t maize grain, energy depletion, acidification, eutrophication, and climate change impacts of INM treatment decreased 26.19, 30.16, 32.61, and 22.75 %, respectively. Therefore, INM treatment is a better N management strategy in comprehensive analysis.

  8. Modeling nitrogen uptake and potential nitrate leaching under different irrigation programs in nitrogen-fertilized tomato using the computer program NLEAP.

    PubMed

    Karaman, M Rüstü; Saltali, Kadir; Ersahin, Sabit; Güleç, Hikmet; Derici, M Rifat

    2005-02-01

    Readily available nitrogen (N) sources such as ammonium nitrate with excessive irrigation present a potential hazard for the environment. The computer program Nitrate Leaching and Economic Analysis Package (NLEAP) is a mechanistic model developed for rapid site-specific estimates of nitrate-nitrogen (NO3-N) moving below the root zone in agricultural crops and potential impacts of NO3-N leaching into groundwater. In this study, the value of NLEAP was tested to simulate N uptake by crops and NO3-N leaching parameters in large lysimeters under the tomato crop. Three seedlings of tomato variety of H-2274 (Lycopersicum esculentum L.) were transplanted into each lysimeter. N fertilizer at the rate of 140 kg N ha(-1) was sidedressed in two split applications, the first half as ammonium sulphate and the second half as ammonium nitrate. The lysimeters were irrigated based on programs of C 0.75, 1.00, 1.25 and 1.50, C referring to class A-Pan evaporation coefficients. Parameters such as leaching index (LI), annual leaching risk potential (ALRP), N available for leaching (NAL), amount of NO3-N leached (NL) and amount of N taken up by the crops (NU) were estimated using the NLEAP computer model. To test the ability of model to simulate N uptake and NL, measured values were compared with simulated values. Significant correlations, R2 = 0.92 and P < 0.03 for the first year and R2 = 0.86 and P < 0.06 for the second year, were found between measured and simulated values for crop N consumption, indicating that the NLEAP model adequately described crop N uptake under the varied irrigation programs using an optimal N fertilization program for the experimental site. Significant correlations, R2 = 0.96 and P < 0.01 for the first year and R2 = 0.97 and P < 0.01 for the second year, were also found between measured and simulated values of NL, indicating that the NLEAP model also adequately predicted NL under the varied irrigation programs. Therefore, this computer model can be useful to

  9. Aqueous and gaseous nitrogen losses induced by fertilizer application

    SciTech Connect

    Gu, C.; Maggi, F.; Riley, W.J.; Hornberger, G.M.; Xu, T.; Oldenburg, C.M.; Spycher, N.; Miller, N.L.; Venterea, R.T.; Steefel, C.

    2009-01-15

    In recent years concern has grown over the contribution of nitrogen (N) fertilizer use to nitrate (NO{sub 3}{sup -}) water pollution and nitrous oxide (N{sub 2}O), nitric oxide (NO), and ammonia (NH{sub 3}) atmospheric pollution. Characterizing soil N effluxes is essential in developing a strategy to mitigate N leaching and emissions to the atmosphere. In this paper, a previously described and tested mechanistic N cycle model (TOUGHREACT-N) was successfully tested against additional observations of soil pH and N{sub 2}O emissions after fertilization and irrigation, and before plant emergence. We used TOUGHREACT-N to explain the significantly different N gas emissions and nitrate leaching rates resulting from the different N fertilizer types, application methods, and soil properties. The N{sub 2}O emissions from NH{sub 4}{sup +}-N fertilizer were higher than from urea and NO{sub 3}{sup -}-N fertilizers in coarse-textured soils. This difference increased with decreases in fertilization application rate and increases in soil buffering capacity. In contrast to methods used to estimate global terrestrial gas emissions, we found strongly non-linear N{sub 2}O emissions as a function of fertilizer application rate and soil calcite content. Speciation of predicted gas N flux into N{sub 2}O and N{sub 2} depended on pH, fertilizer form, and soil properties. Our results highlighted the need to derive emission and leaching factors that account for fertilizer type, application method, and soil properties.

  10. Use of a new GIS nitrogen index assessment tool for evaluation of nitrate leaching across a Mediterranean Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Mediterranean region of Valencia and its Nitrogen Vulnerable Zone have reportedly been affected by Nitrogen (N) losses from agricultural systems. Reported underground water NO3-N concentrations in this area have been as high as 99 mg NO3-N L-1. We tested the approach used by Delgado et al. (2006...

  11. Aqeuous and Gaseous Nitrogen Losses Induced by Fertilizer Application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years concern has grown over the contribution of nitrogen (N) fertilizers to nitrate (NO3-) water pollution and atmospheric pollution of nitrous oxide (N2O), nitric oxide (NO), and ammonia (NH3). Characterizing the amount and species of N losses is therefore essential in developing a strat...

  12. Nitrate leaching and nitrogen recovery following application of polyolefin-coated urea to potato.

    PubMed

    Zvomuya, Francis; Rosen, Carl J; Russelle, Michael P; Gupta, Satish C

    2003-01-01

    High N fertilizer and irrigation amounts applied to potato (Solanum tuberosum L.) on coarse-textured soils often result in nitrate (NO3) leaching and low recovery of applied fertilizer N. This 3-yr study compared the effects of two rates (140 and 280 kg N ha(-1)) of a single polyolefin-coated urea (PCU) application versus split applications of urea on 'Russet Burbank' potato yield and on NO3 leaching and N recovery efficiency (RE) on a loamy sand. Standard irrigation was applied in all years and excessive irrigation was used in another experiment in the third year. At the recommended rate of 280 kg N ha(-1), NO3 leaching during the growing season was 34 to 49% lower with PCU than three applications of urea. Under standard irrigation in the third year, leaching from five applications of urea (280 kg N ha(-1)) was 38% higher than PCU. Under leaching conditions in the first year (> or = 25 mm drainage water in at least one 24-h period) and excessive irrigation in the third year, PCU at 280 kg N ha(-1) improved total and marketable tuber yields by 12 to 19% compared with three applications of urea. Fertilizer N RE estimated by the difference and 15N isotope methods at the 280 kg N ha(-1) rate was, on average, higher with PCU (mean 50%) than urea (mean 43%). Fertilizer N RE values estimated by the isotope method (mean 51%) were greater than those estimated by the difference method (mean 47%). Results from this study indicate that PCU can reduce leaching and improve N recovery and tuber yield during seasons with high leaching.

  13. Nitrogen Fertilization Effects on Productivity and Nitrogen Loss in Three Grass-Based Perennial Bioenergy Cropping Systems.

    PubMed

    Duran, Brianna E L; Duncan, David S; Oates, Lawrence G; Kucharik, Christopher J; Jackson, Randall D

    2016-01-01

    Nitrogen (N) fertilization can greatly improve plant productivity but needs to be carefully managed to avoid harmful environmental impacts. Nutrient management guidelines aimed at reducing harmful forms of N loss such as nitrous oxide (N2O) emissions and nitrate (NO3(-)) leaching have been tailored for many cropping systems. The developing bioenergy industry is likely to make use of novel cropping systems, such as polycultures of perennial species, for which we have limited nutrient management experience. We studied how a switchgrass (Panicum virgatum) monoculture, a 5-species native grass mixture and an 18-species restored prairie responded to annual fertilizer applications of 56 kg N ha(-1) in a field-scale agronomic trial in south-central Wisconsin over a 2-year period. We observed greater fertilizer-induced N2O emissions and sub-rooting zone NO3(-) concentrations in the switchgrass monoculture than in either polyculture. Fertilization increased aboveground net primary productivity in the polycultures, but not in the switchgrass monoculture. Switchgrass was generally more productive, while the two polycultures did not differ from each other in productivity or N loss. Our results highlight differences between polycultures and a switchgrass monoculture in responding to N fertilization.

  14. Nitrogen Fertilization Effects on Productivity and Nitrogen Loss in Three Grass-Based Perennial Bioenergy Cropping Systems

    PubMed Central

    Duran, Brianna E. L.; Duncan, David S.; Oates, Lawrence G.; Kucharik, Christopher J.; Jackson, Randall D.

    2016-01-01

    Nitrogen (N) fertilization can greatly improve plant productivity but needs to be carefully managed to avoid harmful environmental impacts. Nutrient management guidelines aimed at reducing harmful forms of N loss such as nitrous oxide (N2O) emissions and nitrate (NO3-) leaching have been tailored for many cropping systems. The developing bioenergy industry is likely to make use of novel cropping systems, such as polycultures of perennial species, for which we have limited nutrient management experience. We studied how a switchgrass (Panicum virgatum) monoculture, a 5-species native grass mixture and an 18-species restored prairie responded to annual fertilizer applications of 56 kg N ha-1 in a field-scale agronomic trial in south-central Wisconsin over a 2-year period. We observed greater fertilizer-induced N2O emissions and sub-rooting zone NO3- concentrations in the switchgrass monoculture than in either polyculture. Fertilization increased aboveground net primary productivity in the polycultures, but not in the switchgrass monoculture. Switchgrass was generally more productive, while the two polycultures did not differ from each other in productivity or N loss. Our results highlight differences between polycultures and a switchgrass monoculture in responding to N fertilization. PMID:26991790

  15. Nitrogen Fertilization Effects on Productivity and Nitrogen Loss in Three Grass-Based Perennial Bioenergy Cropping Systems

    SciTech Connect

    Duran, Brianna E. L.; Duncan, David S.; Oates, Lawrence G.; Kucharik, Christopher J.; Jackson, Randall D.

    2016-03-18

    Nitrogen (N) fertilization can greatly improve plant productivity but needs to be carefully managed to avoid harmful environmental impacts. Nutrient management guidelines aimed at reducing harmful forms of N loss such as nitrous oxide (N2O) emissions and nitrate (NO3 -) leaching have been tailored for many cropping systems. The developing bioenergy industry is likely to make use of novel cropping systems, such as polycultures of perennial species, for which we have limited nutrient management experience. We studied how a switchgrass (Panicum virgatum) monoculture, a 5-species native grass mixture and an 18- species restored prairie responded to annual fertilizer applications of 56 kg N ha-1 in a fieldscale agronomic trial in south-central Wisconsin over a 2-year period.We observed greater fertilizer-induced N2O emissions and sub-rooting zone NO3 - concentrations in the switchgrass monoculture than in either polyculture. Fertilization increased aboveground net primary productivity in the polycultures, but not in the switchgrass monoculture. Switchgrass was generally more productive, while the two polycultures did not differ from each other in productivity or N loss. In conclusion, our results highlight differences between polycultures and a switchgrass monoculture in responding to N fertilization.

  16. Nitrogen Fertilization Effects on Productivity and Nitrogen Loss in Three Grass-Based Perennial Bioenergy Cropping Systems

    DOE PAGES

    Duran, Brianna E. L.; Duncan, David S.; Oates, Lawrence G.; ...

    2016-03-18

    Nitrogen (N) fertilization can greatly improve plant productivity but needs to be carefully managed to avoid harmful environmental impacts. Nutrient management guidelines aimed at reducing harmful forms of N loss such as nitrous oxide (N2O) emissions and nitrate (NO3 -) leaching have been tailored for many cropping systems. The developing bioenergy industry is likely to make use of novel cropping systems, such as polycultures of perennial species, for which we have limited nutrient management experience. We studied how a switchgrass (Panicum virgatum) monoculture, a 5-species native grass mixture and an 18- species restored prairie responded to annual fertilizer applications ofmore » 56 kg N ha-1 in a fieldscale agronomic trial in south-central Wisconsin over a 2-year period.We observed greater fertilizer-induced N2O emissions and sub-rooting zone NO3 - concentrations in the switchgrass monoculture than in either polyculture. Fertilization increased aboveground net primary productivity in the polycultures, but not in the switchgrass monoculture. Switchgrass was generally more productive, while the two polycultures did not differ from each other in productivity or N loss. In conclusion, our results highlight differences between polycultures and a switchgrass monoculture in responding to N fertilization.« less

  17. Inorganic nitrogen leaching from organic and conventional rice production on a newly claimed calciustoll in Central Asia.

    PubMed

    Meng, Fanqiao; Olesen, Jørgen E; Sun, Xiangping; Wu, Wenliang

    2014-01-01

    Characterizing the dynamics of nitrogen (N) leaching from organic and conventional paddy fields is necessary to optimize fertilization and to evaluate the impact of these contrasting farming systems on water bodies. We assessed N leaching in organic versus conventional rice production systems of the Ili River Valley, a representative aquatic ecosystem of Central Asia. The N leaching and overall performance of these systems were measured during 2009, using a randomized block experiment with five treatments. PVC pipes were installed at soil depths of 50 and 180 cm to collect percolation water from flooded organic and conventional paddies, and inorganic N (NH4-N+NO3-N) was analyzed. Two high-concentration peaks of NH4-N were observed in all treatments: one during early tillering and a second during flowering. A third peak at the mid-tillering stage was observed only under conventional fertilization. NO3-N concentrations were highest at transplant and then declined until harvest. At the 50 cm soil depth, NO3-N concentration was 21-42% higher than NH4-N in percolation water from organic paddies, while NH4-N and NO3-N concentrations were similar for the conventional and control treatments. At the depth of 180 cm, NH4-N and NO3-N were the predominant inorganic N for organic and conventional paddies, respectively. Inorganic N concentrations decreased with soil depth, but this attenuation was more marked in organic than in conventional paddies. Conventional paddies leached a higher percentage of applied N (0.78%) than did organic treatments (0.32-0.60%), but the two farming systems leached a similar amount of inorganic N per unit yield (0.21-0.34 kg N Mg(-1) rice grains). Conventional production showed higher N utilization efficiency compared to fertilized organic treatments. These results suggest that organic rice production in the Ili River Valley is unlikely to reduce inorganic N leaching, if high crop yields similar to conventional rice production are to be maintained.

  18. Inorganic Nitrogen Leaching from Organic and Conventional Rice Production on a Newly Claimed Calciustoll in Central Asia

    PubMed Central

    Meng, Fanqiao; Olesen, Jørgen E.; Sun, Xiangping; Wu, Wenliang

    2014-01-01

    Characterizing the dynamics of nitrogen (N) leaching from organic and conventional paddy fields is necessary to optimize fertilization and to evaluate the impact of these contrasting farming systems on water bodies. We assessed N leaching in organic versus conventional rice production systems of the Ili River Valley, a representative aquatic ecosystem of Central Asia. The N leaching and overall performance of these systems were measured during 2009, using a randomized block experiment with five treatments. PVC pipes were installed at soil depths of 50 and 180 cm to collect percolation water from flooded organic and conventional paddies, and inorganic N (NH4-N+NO3-N) was analyzed. Two high-concentration peaks of NH4-N were observed in all treatments: one during early tillering and a second during flowering. A third peak at the mid-tillering stage was observed only under conventional fertilization. NO3-N concentrations were highest at transplant and then declined until harvest. At the 50 cm soil depth, NO3-N concentration was 21–42% higher than NH4-N in percolation water from organic paddies, while NH4-N and NO3-N concentrations were similar for the conventional and control treatments. At the depth of 180 cm, NH4-N and NO3-N were the predominant inorganic N for organic and conventional paddies, respectively. Inorganic N concentrations decreased with soil depth, but this attenuation was more marked in organic than in conventional paddies. Conventional paddies leached a higher percentage of applied N (0.78%) than did organic treatments (0.32–0.60%), but the two farming systems leached a similar amount of inorganic N per unit yield (0.21–0.34 kg N Mg−1 rice grains). Conventional production showed higher N utilization efficiency compared to fertilized organic treatments. These results suggest that organic rice production in the Ili River Valley is unlikely to reduce inorganic N leaching, if high crop yields similar to conventional rice production are to be

  19. Dissolved Organic Carbon and Nitrogen Leaching From Soil Formed in Grass, Oak and Pine Ecosystems of California

    NASA Astrophysics Data System (ADS)

    Pittiglio, S. L.; Zasoski, R. J.

    2005-12-01

    Dissolved organic matter (DOM) leaching from decomposing detritus accumulated above mineral soils is an important carbon (C) and nitrogen (N) flux that influences biogeochemical processes, C sequestration and the health of individual ecosystems. This study compared the retention and transformation of DOM leached through soils formed under three contrasting vegetation types. In a laboratory study, columns of surface soil (10 cm diameter, 10 cm height) from either a grass, oak or pine site were leached with DOM derived from either grass, oak or pine litter. In the field, the laboratory study was replicated by burying columns of soil from the grass, oak and pine sites under the organic horizon at each sites. Leachates from in-situ field columns were collected biweekly beginning in January 2005. Samples were analyzed for volume, pH, total N, NO3-, NH4+, DON and DOC. In the laboratory leaching studies soils retained DOC derived from its native ecosystem to a greater extent. These results suggest that the microbial community from each ecosystem is adapted to consume the native DOC. No clear trends were found with DOC in the field study. Leachates from the field columns did show significantly lower levels of DON from pine soil columns at all sampling dates and sites. Similar results were found in the laboratory study with pine soil decreasing initial total N inputs from 32.9 to 3.6 mg kg-1. While all three sites contain kaolinite, vermiculite and chlorite, soil from the pine site also has high levels of iron oxides and gibbsite. The greater iron content likely contributes to higher DON retention since these minerals are know to have high affinities for the retention of DOM. The results from the field and laboratory experiments show that both soil minerals and the soil microbial communities play an important role in DOM retention in the subsoil.

  20. Effects of soil moisture content on upland nitrogen loss

    NASA Astrophysics Data System (ADS)

    Ouyang, Wei; Xu, Xueting; Hao, Zengchao; Gao, Xiang

    2017-03-01

    In recent years, nitrogen (N) loss from upland fields has become one of the most important sources for agricultural nonpoint source (NPS) pollution. Understanding the relationships between soil hydrological processes and N loss in NPS pollution is vital for controlling the agricultural NPS pollution in upland fields. The objective of this study was to analyze the interaction of N loss with different moisture conditions in the freeze-thaw zone. The semi-distributed hydrologic model Soil and Water Assessment Tool (SWAT) was used in this study to simulate runoff and different forms of N loss, which provided a basis for analyzing characteristics of N loss in the study region. Results showed that the soil moisture content was an important factor affecting N loss in the study region. Different forms of N loss were also analyzed and it was found that N loss occurred primarily in the form of organic-N, which is likely due to the dominant role of erosion-induced pollution. This study provides useful information for preventing NPS pollution within the study region.

  1. Measures of nitrogen use efficiency and nitrogen loss from dairy production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive N use in agriculture can impair air and water quality. The purpose of this paper is to examine how stocking rate, feed imports, fertilizer N use and different measures of N use and N loss impact nitrogen use efficiency (NUE) in dairy production systems. First, determinations of NUE and N l...

  2. Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model.

    PubMed

    Guo, Ruiying; Nendel, Claas; Rahn, Clive; Jiang, Chunguang; Chen, Qing

    2010-06-01

    Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model. EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter.

  3. Practices to reduce nitrate leaching and increase nitrogen use efficiency in irrigated agriculture

    NASA Astrophysics Data System (ADS)

    Quemada, Miguel; Baranski, Marcin; Nobel de Lange, Majimcha; Vallejo, Antonio; Cooper, Julia

    2013-04-01

    Despite the large body of research in irrigated agriculture, it is still not clear which practices most effectively reduce nitrate leaching (NL) while maintaining crop yield. A meta-analysis (MA) of published experimental results from agricultural irrigated systems was conducted to identify those agricultural practices that have proven effective at reducing NL and to quantify the scale of reduction that can be achieved. Forty-four scientific articles were identified which investigated four main strategies (water and fertilizer management, use of cover crops and fertilizer technology) creating a database with 279 observations on NL and 166 on crop yield. Management practices that adjust water application to crop needs reduced NL by a mean of 80% without a reduction in crop yield. Improved fertilizer management reduced NL by 40%, and the best relationship between yield and NL was obtained when applying the recommended N fertilizer rate. Applications above the recommended rate increased leaching without enhancing yield. Replacing a fallow with a non-legume cover crop (CC) reduced NL by 50% while using a legume CC did not have any effect on NL. Legume CC increased yield and N use efficiency while yields following non-legume CC were not different from the fallow. Improved fertilizer technology also decreased NL but was the least effective of the selected strategies. The risk of nitrate leaching from irrigated systems is high, but optimum management practices may mitigate this risk and maintain crop yields while enhancing environmental sustainability.

  4. Nitrogen retention efficiency and nitrogen losses of a managed and phytodiverse temperate grassland

    NASA Astrophysics Data System (ADS)

    Keuter, A.

    2012-04-01

    In consequence of the increasing global population, it is necessary to keep N losses at the minimum while maintaining soil fertility and high yields. The goal of our study was to assess how management practices and sward functional diversity affected N losses and N retention efficiency in a temperate grassland. We measured N retention efficiency as the ratio of N losses (N2O emission and NO3- and DON leaching) to soil available N (gross N mineralization rates). Our study was conducted in a grassland management experiment (GRASSMAN) located in Solling, Germany; the experimental design was three-factorial with two mowing frequencies (cut once and thrice per year), two fertilization treatments (180 - 30 - 100 kg NPK ha-1 yr-1 and no fertilization), and three sward compositions (dicot-enhanced swards with nearly equal proportions of dicots and monocots, control swards with ~ 70% monocots and ~ 30% dicots and monocot-enhanced swards with ~90% monocots and 10% dicots). N2O emission and NO3 leaching were significantly increased by fertilization and decreased by more frequent mowing. An interaction between these factors showed that frequent mowing can mitigate the negative effects of fertilization on N losses. N retention efficiency was largely influenced by fertilization and sward composition: N retention efficiencies were larger in unfertilized plots than fertilized plots, and decreased in the order of control > dicot-enhanced > monocot-enhanced swards. Microbial N immobilization turned out to be more important for N retention than plant N uptake. We concluded that over the past 5 decades the prevailing management practices have led to an equilibrium sward composition in this grassland ecosystem in which optimal proportions of monocots and dicots (i.e. unmanipulated control plots) developed to maximize N retention efficiency. Deviations from these proportions reduce N retention efficiency.

  5. Nitrogen inputs and losses in response to chronic CO2 exposure in a sub-tropical oak woodland

    NASA Astrophysics Data System (ADS)

    Hungate, B. A.; Duval, B. D.; Dijkstra, P.; Johnson, D. W.; Ketterer, M. E.; Stiling, P.; Cheng, W.; Millman, J.; Hartley, A.; Stover, D. B.

    2014-01-01

    Rising atmospheric CO2 concentrations could alter the nitrogen (N) content of ecosystems by changing N inputs and N losses, but responses vary in field experiments, possibly because multiple mechanisms are at play. We measured N fixation and N losses in a subtropical oak woodland exposed to 11 yr of elevated atmospheric CO2 concentrations. We also explored the role of herbivory, carbon limitation, and competition for light and nutrients in shaping response of N fixation to elevated CO2. Elevated CO2 did not significantly alter gaseous N losses, but lower recovery and deeper distribution in the soil of a long-term 15N tracer indicated that elevated CO2 increased leaching losses. Elevated CO2 had no effect on asymbiotic N fixation, and had a transient effect on symbiotic N fixation by the dominant legume. Elevated CO2 tended to reduce soil and plant concentrations of iron, molybdenum, phosphorus, and vanadium, nutrients essential for N fixation. Competition for nutrients and herbivory likely contributed to the declining response N fixation to elevated CO2. These results indicate that positive responses of N fixation to elevated CO2 may be transient, and that chronic exposure to elevated CO2 can increase N leaching. Models that assume increased fixation or reduced N losses with elevated CO2 may overestimate future N accumulation in the biosphere.

  6. Use It or Lose It: Advances in Our Understanding of Terrestrial Nitrogen Retention and Loss (Invited)

    NASA Astrophysics Data System (ADS)

    Silver, W. L.; Yang, W. H.

    2013-12-01

    Understanding of the terrestrial nitrogen (N) cycle has grown over the last decade to include a variety of pathways that have the potential to either retain N in the ecosystem or result in losses to the atmosphere or groundwater. Early work has described the mechanics of these N transformations, but the relevance of these processes to ecosystem, regional, or global scale N cycling has not been well quantified. In this study, we review advances in our understanding of the terrestrial N cycle, and focus on three pathways with particular relevance to N retention and loss: dissimilatory nitrate and nitrite reduction to ammonium (DNRA), anaerobic ammonium oxidation (annamox), and anaerobic ammonium oxidation coupled to iron reduction (Feammox). We discuss the role of these processes in the microbial N economy (sensu Burgin et al. 2011) of the terrestrial N cycle, the environmental and ecological constraints, and relationships with other key biogeochemical cycles. We also discuss recent advances in analytical approaches that have improved our ability to detect these and related N fluxes in terrestrial ecosystems. Finally, we present a scaling exercise that identifies the potential importance of these pathways for N retention and loss across a range of spatial and temporal scales, and discuss their significance in terms of N limitation to net primary productivity, N leaching to groundwater, and the release of reactive N gases to the atmosphere.

  7. Nitrogen Utilization and Environmental Losses from Organic Farming and Biochar's Potential to Improve N Efficiency.

    NASA Astrophysics Data System (ADS)

    Pereira, E. I.; SIX, J. W. U. A.

    2014-12-01

    The response of plant performance and nitrogen (N) dynamics to biochar amendments were studied across various levels of N input for two growing seasons in mesocosms representing an organic lettuce production systems. A silt loam soil was amended with pine chip (PC) and walnut shell (WS) biochar (10 t ha-1) in combination with five organic N fertilization rates 0%, 25%, 50%, 75%, and 100% of 225 kg N ha-1. N output through harvest, leachate, and nitrous oxide (N2O) emissions were determined to assess N utilization and environmental losses of biochar-amended soils. Analysis of plant performance indicate that PC and WS biochar did not provide any increases in plant biomass in soils that received less than business-as-usual fertilization rates. At 100% N fertilization rate, biochar amendments (both PC and WS) improved lettuce biomass production, which resulted in significant increases in NUE with no effects on N2O emissions. Furthermore, N losses via leaching were decreased by PC biochar at 100% N fertilization rates. Thus, due to increases in plant biomass and decreases in N losses via leachate, PC biochar significantly decreased the ratio of N lost over N exported in biomass. Findings from this study suggest that biochar can provide some beneficial effects to organic farming systems, however, not in all circumstances, given the effects seem to vary with biochar type and fertilization level.

  8. Leaching of nitrogen and phenolics from wood waste and co-composts used for road rehabilitation.

    PubMed

    Venner, K H; Prescott, C E; Preston, C M

    2009-01-01

    Rehabilitation and reforestation of disused forest roads and landings can be facilitated by the incorporation of organic matter. The British Columbia forest industry creates residual woody materials, but they are nutrient poor and may leach phenolic compounds. We assessed the potential for wood wastes (chipped cedar wood waste, sort-yard waste, hogfuel) and co-composts with shellfish waste or municipal biosolids to provide inorganic N and release phenolics and condensed tannins, compared with natural forest floor and mineral soil. Initial concentrations of tannins and phenolics were low, and 13C cross-polarization and magic-angle spinning nuclear magnetic resonance spectroscopy showed that composts were still dominated by wood. During a 426-d laboratory leaching experiment, release of phenolics from woody amendments (other than cedar wood) was lower than from native forest floor. The pH levels of woody amendments and their leachates were also within the range of native forest floor and soil (except cedar wood, which was the most acidic material). Co-composts had higher total N and available P, greatly reduced tannins and phenolics, and negligible leaching of polyphenols. Uncomposted materials released very little N during the incubation. Hogfuel-biosolids compost released a large amount of nitrate, but only during the first 100 d. Shrimp-wood compost released moderate amounts of ammonium and nitrate throughout the incubation, had high available P and low tannin content, and released less polyphenols than did native forest floors. Our results indicate that appropriate use of these amendments does not pose an environmental risk with regard to the parameters measured in this study.

  9. Nitrogen loss in surface runoff from Chinese cabbage fields

    NASA Astrophysics Data System (ADS)

    Xi-Yuan, Wu; Zhang, Li-Ping; Fu, Xing-Tao; Wang, Xiao-Yun; Zhang, He-Si

    A growth period of Chinese cabbage included seedling, rosette, anterior folding, middle folding, and posterior folding stages. To investigate characteristic of surface runoff, evolution of various nitrogen (N) forms at different growth stages, and contribution of N loss during a whole growth period to environment, 10 simulated rainfalls were applied on Chinese cabbage planted in two 2 m 2 troughs (A and B), with two replicates. Troughs A and B were designed with slopes of 14° and 21°. Five simulated rainfalls were applied in each trough. Seedling and rosette stages were with rainfall intensities of 0.65 mm min -1 and folding stages were with 1.93 mm min -1, respectively. Fertilizers were applied at seedling and anterior folding stages at rate of 103 and 103 kg N ha -1, respectively. One rainfall event lasted for approximately 20 min. Conclusions were as follows: N loss mainly occurred at rosette stage and anterior folding stage. Nitrogen loss had a close relationship with runoff volume. Percentage of NH4+-N in TN had an ascending trend with growth of Chinese cabbage while percentage of NO3--N had a descending trend. Folding stages had more percentages of undissolved N than seedling and rosette stages. Lower slope was advantageous to the concentrations of TN, NO3--N, and NH4+-N and proportion of NO3--N. Based on the results, we need to pay more attention to the NO3--N pollution in Chinese cabbage filed at lower slope.

  10. [Effects of simulated nitrogen deposition on organic matter leaching in forest soil].

    PubMed

    Duan, Lei; ma, Xiao-Xiao; Yu, De-Xiang; Tan, Bing-Quan

    2013-06-01

    The impact of nitrogen deposition on the dynamics of carbon pool in forest soil was studied through a field experiment at Tieshanping, Chongqing in Southwest China. The changes of dissolved organic matter (DOM) concentration in soil water in different soil layers were monitored for five years after addition of ammonium nitrate (NH4NO3) or sodium nitrate (NaNO3) at the same dose as the current nitrogen deposition to the forest floor. The results indicated that the concentration and flux of dissolved organic carbon (DOC) were increased in the first two years and then decreased by fertilizing. Fertilizing also reduced the DOC/DON (dissolved organic nitrogen) ratio of soil water in the litter layer and the DOC concentration of soil water in the upper mineral layer, but had no significant effect on DOC flux in the lower soil layer. Although there was generally no effect of increasing nitrogen deposition on the forest carbon pool during the experimental period, the shift from C-rich to N-rich DOM might occur. In addition, the species of nitrogen deposition, i. e., NH4(+) and NO3(-), did not show difference in their effect on soil DOM with the same equivalence.

  11. Benthic nitrogen loss in the arabian sea off pakistan.

    PubMed

    Sokoll, Sarah; Holtappels, Moritz; Lam, Phyllis; Collins, Gavin; Schlüter, Michael; Lavik, Gaute; Kuypers, Marcel M M

    2012-01-01

    A pronounced deficit of nitrogen (N) in the oxygen minimum zone (OMZ) of the Arabian Sea suggests the occurrence of heavy N-loss that is commonly attributed to pelagic processes. However, the OMZ water is in direct contact with sediments on three sides of the basin. Contribution from benthic N-loss to the total N-loss in the Arabian Sea remains largely unassessed. In October 2007, we sampled the water column and surface sediments along a transect cross-cutting the Arabian Sea OMZ at the Pakistan continental margin, covering a range of station depths from 360 to 1430 m. Benthic denitrification and anammox rates were determined by using (15)N-stable isotope pairing experiments. Intact core incubations showed declining rates of total benthic N-loss with water depth from 0.55 to 0.18 mmol N m(-2) day(-1). While denitrification rates measured in slurry incubations decreased from 2.73 to 1.46 mmol N m(-2) day(-1) with water depth, anammox rates increased from 0.21 to 0.89 mmol N m(-2) day(-1). Hence, the contribution from anammox to total benthic N-loss increased from 7% at 360 m to 40% at 1430 m. This trend is further supported by the quantification of cd(1)-containing nitrite reductase (nirS), the biomarker functional gene encoding for cytochrome cd(1)-Nir of microorganisms involved in both N-loss processes. Anammox-like nirS genes within the sediments increased in proportion to total nirS gene copies with water depth. Moreover, phylogenetic analyses of NirS revealed different communities of both denitrifying and anammox bacteria between shallow and deep stations. Together, rate measurement and nirS analyses showed that anammox, determined for the first time in the Arabian Sea sediments, is an important benthic N-loss process at the continental margin off Pakistan, especially in the sediments at deeper water depths. Extrapolation from the measured benthic N-loss to all shelf sediments within the basin suggests that benthic N-loss may be

  12. Benthic Nitrogen Loss in the Arabian Sea Off Pakistan

    PubMed Central

    Sokoll, Sarah; Holtappels, Moritz; Lam, Phyllis; Collins, Gavin; Schlüter, Michael; Lavik, Gaute; Kuypers, Marcel M. M.

    2012-01-01

    A pronounced deficit of nitrogen (N) in the oxygen minimum zone (OMZ) of the Arabian Sea suggests the occurrence of heavy N-loss that is commonly attributed to pelagic processes. However, the OMZ water is in direct contact with sediments on three sides of the basin. Contribution from benthic N-loss to the total N-loss in the Arabian Sea remains largely unassessed. In October 2007, we sampled the water column and surface sediments along a transect cross-cutting the Arabian Sea OMZ at the Pakistan continental margin, covering a range of station depths from 360 to 1430 m. Benthic denitrification and anammox rates were determined by using 15N-stable isotope pairing experiments. Intact core incubations showed declining rates of total benthic N-loss with water depth from 0.55 to 0.18 mmol N m−2 day−1. While denitrification rates measured in slurry incubations decreased from 2.73 to 1.46 mmol N m−2 day−1 with water depth, anammox rates increased from 0.21 to 0.89 mmol N m−2 day−1. Hence, the contribution from anammox to total benthic N-loss increased from 7% at 360 m to 40% at 1430 m. This trend is further supported by the quantification of cd1-containing nitrite reductase (nirS), the biomarker functional gene encoding for cytochrome cd1-Nir of microorganisms involved in both N-loss processes. Anammox-like nirS genes within the sediments increased in proportion to total nirS gene copies with water depth. Moreover, phylogenetic analyses of NirS revealed different communities of both denitrifying and anammox bacteria between shallow and deep stations. Together, rate measurement and nirS analyses showed that anammox, determined for the first time in the Arabian Sea sediments, is an important benthic N-loss process at the continental margin off Pakistan, especially in the sediments at deeper water depths. Extrapolation from the measured benthic N-loss to all shelf sediments within the basin suggests that benthic N-loss may be

  13. Reduced nitrogen losses following conversion of row crop agriculture to perennial biofuel crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current biofuel feedstock crops such as corn lead to large environmental losses of N through nitrate leaching and N2O emissions, and require large inputs of N fertilizer. Second generation cellulosic crops have the potential to reduce these N losses, and provide even greater biomass for conversion t...

  14. Chemical precipitation for controlling nitrogen loss during composting.

    PubMed

    Ren, Li-Mei; Li, Guo-Xue; Shen, Yun-Jun; Schuchardt, Frank; Lu Peng

    2010-05-01

    Aimed at controlling the nitrogen loss during composting, the mixture of magnesium hydroxide (Mg(OH)( 2)) and phosphoric acid (H(3)PO(4)) (molar ratio 1:2) were utilized as additives to avoid increasing total salinity. In trial TA, the additives were put into absorption bottles connecting with a gas outlet of fermentor (ex situ method); in trial TB, the additives were directly added to the composting materials (in situ method). During the 26 day composting period, the temperature, pH, total organic carbon (TOC), total nitrogen (TN), ammonium nitrogen (NH(4)(+)-N), total phosphorus (TP), available phosphorus (AP) and germination index (GI) were measured. The experimental results show that the additives reduced the pH, while NH( 4)(+)-N and TN were obviously improved. NH(4)( +)-N was 11.9 g kg(-1) and 3 g kg(- 1) in amended compost trial (TB) and unamended compost trial (TA), respectively; TN increased from 26.5 g kg(-1) to 40.3 g kg(-1) in TB and increased from 26.5 g kg( -1) to 26.8 g kg(-1) in TA. Analysis of the TOC and carbon mass revealed that absorbents accelerated the degradation of organic matter. The germination index test showed the maturity of TB (102%) was better than TA (82%) in final compost. Furthermore, TP and AP were also obviously improved. X-ray diffraction analysis of precipitation showed that the precipitation in absorption bottle of TA was newberyite (MgHPO( 4) 3H(2)O), however, the crystal in the TB compost was struvite (MgNH(4)PO(4) 6H(2)O: magnesium ammonium phosphate). These results indicated that Mg(OH)(2) and H(3)PO( 4) could reduce the ammonia emission by struvite crystallization reaction. Optimal conditions for struvite precipitation should be determined for different systems.

  15. SAR11 bacteria linked to ocean anoxia and nitrogen loss

    PubMed Central

    Tsementzi, Despina; Wu, Jieying; Deutsch, Samuel; Nath, Sangeeta; Rodriguez-R, Luis M; Burns, Andrew S.; Ranjan, Piyush; Sarode, Neha; Malmstrom, Rex R.; Padilla, Cory C.; Stone, Benjamin K.; Bristow, Laura A.; Larsen, Morten; Glass, Jennifer B.; Thamdrup, Bo; Woyke, Tanja; Konstantinidis, Konstantinos T.; Stewart, Frank J.

    2016-01-01

    Summary Bacteria of the SAR11 clade constitute up to one half of all microbial cells in the oxygen-rich surface ocean. DNA sequences from SAR11 are also abundant in oxygen minimum zones (OMZs) where oxygen falls below detection and anaerobic microbes play important roles in converting bioavailable nitrogen to N2 gas. Evidence for anaerobic metabolism in SAR11 has not yet been observed, and the question of how these bacteria contribute to OMZ biogeochemical cycling is unanswered. Here, we identify the metabolic basis for SAR11 activity in anoxic ocean waters. Genomic analysis of single cells from the world’s largest OMZ revealed diverse and previously uncharacterized SAR11 lineages that peak in abundance at anoxic depths, but are largely undetectable in oxygen-rich ocean regions. OMZ SAR11 contain adaptations to low oxygen, including genes for respiratory nitrate reductases (Nar). SAR11 nar genes were experimentally verified to encode proteins catalyzing the nitrite-producing first step of denitrification and constituted ~40% of all OMZ nar transcripts, with transcription peaking in the zone of maximum nitrate reduction rates. These results redefine the ecological niche of Earth’s most abundant organismal group and suggest an important contribution of SAR11 to nitrite production in OMZs, and thus to pathways of ocean nitrogen loss. PMID:27487207

  16. SAR11 bacteria linked to ocean anoxia and nitrogen loss

    NASA Astrophysics Data System (ADS)

    Tsementzi, Despina; Wu, Jieying; Deutsch, Samuel; Nath, Sangeeta; Rodriguez-R, Luis M.; Burns, Andrew S.; Ranjan, Piyush; Sarode, Neha; Malmstrom, Rex R.; Padilla, Cory C.; Stone, Benjamin K.; Bristow, Laura A.; Larsen, Morten; Glass, Jennifer B.; Thamdrup, Bo; Woyke, Tanja; Konstantinidis, Konstantinos T.; Stewart, Frank J.

    2016-08-01

    Bacteria of the SAR11 clade constitute up to one half of all microbial cells in the oxygen-rich surface ocean. SAR11 bacteria are also abundant in oxygen minimum zones (OMZs), where oxygen falls below detection and anaerobic microbes have vital roles in converting bioavailable nitrogen to N2 gas. Anaerobic metabolism has not yet been observed in SAR11, and it remains unknown how these bacteria contribute to OMZ biogeochemical cycling. Here, genomic analysis of single cells from the world’s largest OMZ revealed previously uncharacterized SAR11 lineages with adaptations for life without oxygen, including genes for respiratory nitrate reductases (Nar). SAR11 nar genes were experimentally verified to encode proteins catalysing the nitrite-producing first step of denitrification and constituted ~40% of OMZ nar transcripts, with transcription peaking in the anoxic zone of maximum nitrate reduction activity. These results link SAR11 to pathways of ocean nitrogen loss, redefining the ecological niche of Earth’s most abundant organismal group.

  17. Quantifying Nitrogen Loss From Flooded Hawaiian Taro Fields

    NASA Astrophysics Data System (ADS)

    Deenik, J. L.; Penton, C. R.; Bruland, G. L.; Popp, B. N.; Engstrom, P.; Mueller, J. A.; Tiedje, J.

    2010-12-01

    In 2004 a field fertilization experiment showed that approximately 80% of the fertilizer nitrogen (N) added to flooded Hawaiian taro (Colocasia esculenta) fields could not be accounted for using classic N balance calculations. To quantify N loss through denitrification and anaerobic ammonium oxidation (anammox) pathways in these taro systems we utilized a slurry-based isotope pairing technique (IPT). Measured nitrification rates and porewater N profiles were also used to model ammonium and nitrate fluxes through the top 10 cm of soil. Quantitative PCR of nitrogen cycling functional genes was used to correlate porewater N dynamics with potential microbial activity. Rates of denitrification calculated using porewater profiles were compared to those obtained using the slurry method. Potential denitrification rates of surficial sediments obtained with the slurry method were found to drastically overestimate the calculated in-situ rates. The largest discrepancies were present in fields greater than one month after initial fertilization, reflecting a microbial community poised to denitrify the initial N pulse. Potential surficial nitrification rates varied between 1.3% of the slurry-measured denitrification potential in a heavily-fertilized site to 100% in an unfertilized site. Compared to the use of urea, fish bone meal fertilizer use resulted in decreased N loss through denitrification in the surface sediment, according to both porewater modeling and IPT measurements. In addition, sub-surface porewater profiles point to root-mediated coupled nitrification/denitrification as a potential N loss pathway that is not captured in surface-based incubations. Profile-based surface plus subsurface coupled nitrification/denitrification estimates were between 1.1 and 12.7 times denitrification estimates from the surface only. These results suggest that the use of a ‘classic’ isotope pairing technique that employs 15NO3- in fertilized agricultural systems can lead to a drastic

  18. Estimating nitrogen losses in furrow irrigated soil amended by compost using HYDRUS-2D model

    NASA Astrophysics Data System (ADS)

    Iqbal, Shahid; Guber, Andrey; Zaman Khan, Haroon; ullah, Ehsan

    2014-05-01

    Furrow irrigation commonly results in high nitrogen (N) losses from soil profile via deep infiltration. Estimation of such losses and their reduction is not a trivial task because furrow irrigation creates highly nonuniform distribution of soil water that leads to preferential water and N fluxes in soil profile. Direct measurements of such fluxes are impractical. The objective of this study was to assess applicability of HYDRUS-2D model for estimating nitrogen balance in manure amended soil under furrow irrigation. Field experiments were conducted in a sandy loam soil amended by poultry manure compost (PMC) and pressmud compost (PrMC) fertilizers. The PMC and PrMC contained 2.5% and 0.9% N and were applied at 5 rates: 2, 4, 6, 8 and 10 ton/ha. Plots were irrigated starting from 26th day from planting using furrows with 1x1 ridge to furrow aspect ratio. Irrigation depths were 7.5 cm and time interval between irrigations varied from 8 to 15 days. Results of the field experiments showed that approximately the same corn yield was obtained with considerably higher N application rates using PMC than using PrMC as a fertilizer. HYDRUS-2D model was implemented to evaluate N fluxes in soil amended by PMC and PrMC fertilizers. Nitrogen exchange between two pools of organic N (compost and soil) and two pools of mineral N (soil NH4-N and soil NO3-N) was modeled using mineralization and nitrification reactions. Sources of mineral N losses from soil profile included denitrification, root N uptake and leaching with deep infiltration of water. HYDRUS-2D simulations showed that the observed increases in N root water uptake and corn yields associated with compost application could not be explained by the amount of N added to soil profile with the compost. Predicted N uptake by roots significantly underestimated the field data. Good agreement between simulated and field-estimated values of N root uptake was achieved when the rate of organic N mineralization was increased

  19. Nitrogen footprints: Regional realities and options to reduce nitrogen loss to the environment.

    PubMed

    Shibata, Hideaki; Galloway, James N; Leach, Allison M; Cattaneo, Lia R; Cattell Noll, Laura; Erisman, Jan Willem; Gu, Baojing; Liang, Xia; Hayashi, Kentaro; Ma, Lin; Dalgaard, Tommy; Graversgaard, Morten; Chen, Deli; Nansai, Keisuke; Shindo, Junko; Matsubae, Kazuyo; Oita, Azusa; Su, Ming-Chien; Mishima, Shin-Ichiro; Bleeker, Albert

    2017-03-01

    Nitrogen (N) management presents a sustainability dilemma: N is strongly linked to energy and food production, but excess reactive N causes environmental pollution. The N footprint is an indicator that quantifies reactive N losses to the environment from consumption and production of food and the use of energy. The average per capita N footprint (calculated using the N-Calculator methodology) of ten countries varies from 15 to 47 kg N capita(-1) year(-1). The major cause of the difference is the protein consumption rates and food production N losses. The food sector dominates all countries' N footprints. Global connections via trade significantly affect the N footprint in countries that rely on imported foods and feeds. The authors present N footprint reduction strategies (e.g., improve N use efficiency, increase N recycling, reduce food waste, shift dietary choices) and identify knowledge gaps (e.g., the N footprint from nonfood goods and soil N process).

  20. [Effects of applying controlled-release fertilizer blended with conventional nitrogen fertilizer on Chinese cabbage yield and quality as well as nitrogen losses].

    PubMed

    Yang, Jun-gang; Xu, Kai; Tong, Er-jian; Cao, Bing; Ni, Xiao-hui; Xu, Jun-xiang

    2010-12-01

    An open field experiment was conducted to study the effects of applying controlled-release fertilizer blended with rapidly available chemical N fertilizer on Chinese cabbage yield and quality as well as nitrogen losses, including ammonia volatilization and NO3- -N accumulation and leaching in Beijing suburb. The results showed that a combined application of 2:1 controlled-release fertilizer and urea fertilizer (total N rate 150 kg x hm(-2)) did not induce the reduction of Chinese cabbage yield, and decreased the leaf nitrate and organic acid contents significantly, compared with conventional urea N application (300 kg x hm(-2)), and had no significant difference in the cabbage yield and leaf nitrate content, compared with applying 150 kg x hm(-2) of urea N. The combined application of 2:1 controlled-release fertilizer and urea fertilizer improved the N use efficiency of Chinese cabbage, and reduced the ammonia volatilization and NO3- -N leaching. At harvest, the NO3- -N concentrations in 20-40, 60-80 and 80-100 cm soil layers were significantly lower in the combined application treatment than in urea N treatment.

  1. Erosional nitrogen losses in a geomorphologically dynamic wet tropical watershed

    NASA Astrophysics Data System (ADS)

    Weintraub, S. R.; Stallard, R. F.; Taylor, P.; Asner, G. P.; Townsend, A. R.

    2013-12-01

    In erosion-prone watersheds, the loss of nutrients associated with eroding topsoil can be substantial. Previous studies in a geomorphologically dynamic wet-tropical study site demonstrated elevated nitrogen availability, characterized by larger nitrate pools, higher 15-N enrichment, and higher rates of net and potential nitrification, on stable ridge-tops compared to N-poor steep hillslopes. In the current study, we sought to test whether these pronounced differences in N availability were correlated with spatial patterns of erosional N-export. In order to characterize N transport patterns within a small (12-hectare) forested watershed, we buried Gerlach troughs at approximately 15-meter intervals along a 100-meter long study hillslope, beginning at the ridge-slope break and continuing downslope toward the stream. We recovered and analyzed all soil, water, and detritus collected by these troughs over the course of one year and concurrently monitored rainfall and stream discharge. We also measured soil mineralogy, texture, and permeability (Ksat) at the topographic locations where troughs were installed. We observed distinct patterns in the nature and timing of downslope N transport, with shifts in the contribution of dissolved versus particulate losses both across the hillslope and with intensification of wet-season precipitation. Unlike the flat ridge-top, steeper downslope segments exported a substantial amount of N during the late wet season, approximately 85% of which was in particulate form. These slope fluxes help account for much of the watershed- scale losses of > 10 kg particulate N per hectare per year, quantified in a nearby stream. Soil mineralogic and hydraulic characteristics varied in concert with general N export patterns, implying different degrees of soil stability and the dominance of different soil water flowpaths in steeper versus flatter areas. In this forested landscape, geomorphic position determines overland N fluxes and likely couples N

  2. Phosphorus and nitrogen losses from poultry litter stacks and leaching through soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The practice of stacking poultry litter in fields prior to spreading provides important logistical benefits to farmers but is controversial due to its potential to serve as a source of nutrients to leachate and runoff. We evaluated nutrient fate under stacked poultry litter to assess differences in ...

  3. Plant and microbial controls on nitrogen retention and loss in a Humid Tropical Forest

    SciTech Connect

    Templer, P.; Silver, W.; Pett-Ridge, J.; DeAngelis, K.M.; Firestone, M.K.

    2009-09-15

    Humid tropical forests are generally characterized by the lack of nitrogen (N) limitation to net primary productivity, yet paradoxically have high potential for N loss. We conducted an intensive field experiment with {sup 15}NH{sub 4} and {sup 15}NO{sub 3} additions to highly weathered tropical forest soils to determine the relative importance of N retention and loss mechanisms. Over half of all the NH{sub 4}{sup +} produced from gross mineralization was rapidly converted to NO{sub 3}{sup -} during the process of gross nitrification. During the first 24 h plant roots took up 28 % of the N mineralized, dominantly as NH{sub 4}{sup +}, and were a greater sink for N than soil microbial biomass. Soil microbes were not a significant sink for added {sup 15}NH{sub 4}{sup +} or {sup 15}NO{sub 3}{sup -} during the first 24 hr, and only for {sup 15}NH{sub 4}{sup +} after 7 d. Patterns of microbial community composition, as determined by Terminal Restriction Fragment Length Polymorphism analysis, were weakly, but significantly correlated with nitrification and denitrification to N{sub 2}O. Rates of dissimilatory NO{sub 3}{sup -} reduction to NH{sub 4}{sup +} (DNRA) were high in this forest, accounting for up to 25 % of gross mineralization and 35 % of gross nitrification. DNRA was a major sink for NO{sub 3}{sup -} which may have contributed to the lower rates of N{sub 2}O and leaching losses. Despite considerable N conservation via DNRA and plant NH{sub 4}{sup +} uptake, the fate of approximately 45% of the NO{sub 3}{sup -} produced and 22% of the NH{sub 4}{sup +} produced were not measured in our fluxes, suggesting that other important pathways for N retention and loss (e.g., denitrification to N{sub 2}) are important in this system. The high proportion of mineralized N that was rapidly nitrified and the fates of that NO{sub 3}{sup -} highlight the key role of gross nitrification as a proximate control on N retention and loss in humid tropical forest soils. Furthermore, our

  4. Maintaining yields and reducing nitrogen loss in rice-wheat rotation system in Taihu Lake region with proper fertilizer management

    NASA Astrophysics Data System (ADS)

    Xue, Lihong; Yu, Yingliang; Yang, Linzhang

    2014-11-01

    In the Tailake region of China, heavy nitrogen (N) loss of rice-wheat rotation systems, due to high fertilizer-N input with low N use efficiency (NUE), was widely reported. To alleviate the detrimental impacts caused by N loss, it is necessary to improve the fertilizer management practices. Therefore, a 3 yr field experiments with different N managements including organic combined chemical N treatment (OCN, 390 kg N ha-1 yr-1, 20% organic fertilizer), control-released urea treatment (CRU, 390 kg N ha-1 yr-1, 70% resin-coated urea), reduced chemical N treatment (RCN, 390 kg N ha-1 yr-1, all common chemical fertilizer), and site-specific N management (SSNM, 333 kg N ha-1 yr-1, all common chemical fertilizer) were conducted in the Taihu Lake region with the ‘farmer’s N’ treatment (FN, 510 kg N ha-1 yr-1, all common chemical fertilizer) as a control. Grain yield, plant N uptake (PNU), NUE, and N losses via runoff, leaching, and ammonia volatilization were assessed. In the rice season, the FN treatment had the highest N loss and lowest NUE, which can be attributed to an excessive rate of N application. Treatments of OCN and RCN with a 22% reduced N rate from FN had no significant effect on PNU nor the yield of rice in the 3 yr; however, the NUE was improved and N loss was reduced 20-32%. OCN treatment achieved the highest yield, while SSNM has the lowest N loss and highest NUE due to the lowest N rate. In wheat season, N loss decreased about 28-48% with the continuous reduction of N input, but the yield also declined, with the exception of OCN treatment. N loss through runoff, leaching and ammonia volatilization was positively correlated with the N input rate. When compared with the pure chemical fertilizer treatment of RCN under the same N input, OCN treatment has better NUE, better yield, and lower N loss. 70% of the urea replaced with resin-coated urea had no significant effect on yield and NUE improvement, but decreased the ammonia volatilization loss. Soil

  5. Climate, nitrogen limitation, and nitrate losses from tropical rainforests

    NASA Astrophysics Data System (ADS)

    Brookshire, J.; Gerber, S.; Menge, D.

    2010-12-01

    Researchers have long observed that rates of plant growth, litter fall, and decomposition are generally higher in tropical forests than temperate forests. On one hand, this broad geographic pattern has a seemingly simple and intuitive explanation: perennially warm temperatures and ample rainfall in tropical latitudes promote luxuriant vegetative growth and rapid litter decomposition relative to temperate latitudes. However, temperature and moisture also affect other ecosystem processes, which are known to affect plant growth and decomposition. For example, nutrients necessary for biomass growth vary widely in availability across soils and climates and thus have the potential to constrain rates of primary production. In particular, researchers have long observed that many tropical forests accumulate, recycle, and export large amounts of nitrogen (N) relative to temperate forests. Here, we focus on the observation that hydrologic nitrate losses from unpolluted, humid, old-growth tropical forests can be considerably higher than from analogous temperate forests. We ask whether high nitrate losses from tropical forests are consistent with an N-limited ecosystem with proportionally greater inorganic leaks due to larger and faster cycling detrital pools under a warm, wet climate. We evaluate this question in the context of a simple analytical framework of terrestrial N cycling and compare our predictions to data of nitrate-N in stream waters of mature temperate and tropical rainforests. Our model describes the temporal tendency of mineral N pools (predominantly nitrate) in soils. We evaluate N losses under the hypothesis of N limitation, while allowing for parameters sensitive to climate to vary for temperate vs. tropical forests. According to our analysis, the observed 17 fold higher NO3- losses from tropical than temperate forests is only consistent with N limitation if the N uptake rate constant is 4 fold lower in tropical than temperate forests. Given that plant

  6. Effect of ambient temperature on losses of volatile nitrogen compounds from stored laying hen manure.

    PubMed

    Pratt, E V; Rose, S P; Keeling, A A

    2002-09-01

    Eight one tonne lots of laying hen manure were stored in individual, environmentally controlled chambers for 18-weeks at one of four constant temperatures: 12, 15, 20 and 25 degrees C. The losses of volatile nitrogen compounds, ammonia, and changes in dry matter and pH were measured during the storage period. There was a linear (P < 0.001) loss of nitrogen from the manure over the 18-week storage period. This loss represented approximately 60% of the initial nitrogen present in the manure. The rate of nitrogen loss increased non-linearly (P < 0.05) with increasing storage temperature. Poultry housing systems that provide low temperature storage of manure are recommended to reduce the volatile nitrogen losses from egg-laying enterprises.

  7. Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils

    PubMed Central

    Wang, Shanyun; Radny, Dirk; Huang, Shuangbing; Zhuang, Linjie; Zhao, Siyan; Berg, Michael; Jetten, Mike S. M.; Zhu, Guibing

    2017-01-01

    Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA & hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5–67.6% of the N-loss (up to 0.675 gN m−2 d−1), with anammox activities of 0.005–0.74 nmolN g−1 soil h−1, which were even higher than the denitrification rates. By contrast, no significant anammox was measured in the vadose zone. Higher anammox bacterial cell densities were observed (0.75–1.4 × 107 copies g−1 soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for anammox bacteria. The anammox bacterial cells in soils of the vadose zone were all <103 copies g−1 soil. We suggest that the subsurface provides a favorable niche for anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known. PMID:28071702

  8. Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils

    NASA Astrophysics Data System (ADS)

    Wang, Shanyun; Radny, Dirk; Huang, Shuangbing; Zhuang, Linjie; Zhao, Siyan; Berg, Michael; Jetten, Mike S. M.; Zhu, Guibing

    2017-01-01

    Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA & hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5–67.6% of the N-loss (up to 0.675 gN m‑2 d‑1), with anammox activities of 0.005–0.74 nmolN g‑1 soil h‑1, which were even higher than the denitrification rates. By contrast, no significant anammox was measured in the vadose zone. Higher anammox bacterial cell densities were observed (0.75–1.4 × 107 copies g‑1 soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for anammox bacteria. The anammox bacterial cells in soils of the vadose zone were all <103 copies g‑1 soil. We suggest that the subsurface provides a favorable niche for anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known.

  9. Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils.

    PubMed

    Wang, Shanyun; Radny, Dirk; Huang, Shuangbing; Zhuang, Linjie; Zhao, Siyan; Berg, Michael; Jetten, Mike S M; Zhu, Guibing

    2017-01-10

    Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA &hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5-67.6% of the N-loss (up to 0.675 gN m(-2 )d(-1)), with anammox activities of 0.005-0.74 nmolN g(-1 )soil h(-1), which were even higher than the denitrification rates. By contrast, no significant anammox was measured in the vadose zone. Higher anammox bacterial cell densities were observed (0.75-1.4 × 10(7 )copies g(-1 )soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for anammox bacteria. The anammox bacterial cells in soils of the vadose zone were all <10(3 )copies g(-1 )soil. We suggest that the subsurface provides a favorable niche for anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known.

  10. Effects of Mulching and Nitrogen on Soil Nitrate-N Distribution, Leaching and Nitrogen Use Efficiency of Maize (Zea mays L.).

    PubMed

    Wang, Xiukang; Xing, Yingying

    2016-01-01

    Mulching and nitrogen are critical drivers of crop production for smallholders of the Loess Plateau in China. The purpose of this study was to investigate the effect of mulching and nitrogen fertilizer on the soil water content, soil nitrate-N content and vertical distribution in maize root-zone. The experiment was conducted over two consecutive years and used randomly assigned field plots with three replicates. The six treatments consisted of no fertilizer without plastic film (CK), plastic film mulching with no basal fertilizer and no top dressing (MN0), basal fertilizer with no top dressing and no mulching (BN1), plastic film mulching and basal fertilizer with no top dressing (MN1), basal fertilizer and top dressing with no mulching (BN2) and plastic film mulching with basal fertilizer and top dressing (MN2). In the top soil layers, the soil water content was a little high in the plastic film mulching than that without mulching. The mean soil water content from 0 to 40 cm without mulching were 3.35% lower than those measured in the corresponding mulching treatments in 31 days after sowing in 2012. The mulching treatment increased the soil nitrate-N content was observed in the 0-40-cm soil layers. The results indicate that high contents of soil nitrate-N were mainly distributed at 0-20-cm at 31 days after sowing in 2012, and the soil nitrate-N concentration in the MN2 treatment was 1.58 times higher than that did not receive fertilizer. The MN2 treatment greatly increased the soil nitrate-N content in the upper layer of soil (0-40-cm), and the mean soil nitrate-N content was increased nearly 50 mg kg-1 at 105 days after sowing compared with CK treatment in 2012. The soil nitrate-N leaching amount in MN1 treatment was 28.61% and 39.14% lower than BN1 treatment, and the mulch effect attained to 42.55% and 65.27% in MN2 lower than BN2 in both years. The yield increased with an increase in the basal fertilizer, top dressing and plastic film mulching, and the grain

  11. Effects of Mulching and Nitrogen on Soil Nitrate-N Distribution, Leaching and Nitrogen Use Efficiency of Maize (Zea mays L.)

    PubMed Central

    2016-01-01

    Mulching and nitrogen are critical drivers of crop production for smallholders of the Loess Plateau in China. The purpose of this study was to investigate the effect of mulching and nitrogen fertilizer on the soil water content, soil nitrate-N content and vertical distribution in maize root-zone. The experiment was conducted over two consecutive years and used randomly assigned field plots with three replicates. The six treatments consisted of no fertilizer without plastic film (CK), plastic film mulching with no basal fertilizer and no top dressing (MN0), basal fertilizer with no top dressing and no mulching (BN1), plastic film mulching and basal fertilizer with no top dressing (MN1), basal fertilizer and top dressing with no mulching (BN2) and plastic film mulching with basal fertilizer and top dressing (MN2). In the top soil layers, the soil water content was a little high in the plastic film mulching than that without mulching. The mean soil water content from 0 to 40 cm without mulching were 3.35% lower than those measured in the corresponding mulching treatments in 31 days after sowing in 2012. The mulching treatment increased the soil nitrate-N content was observed in the 0–40-cm soil layers. The results indicate that high contents of soil nitrate-N were mainly distributed at 0–20-cm at 31 days after sowing in 2012, and the soil nitrate-N concentration in the MN2 treatment was 1.58 times higher than that did not receive fertilizer. The MN2 treatment greatly increased the soil nitrate-N content in the upper layer of soil (0–40-cm), and the mean soil nitrate-N content was increased nearly 50 mg kg−1 at 105 days after sowing compared with CK treatment in 2012. The soil nitrate-N leaching amount in MN1 treatment was 28.61% and 39.14% lower than BN1 treatment, and the mulch effect attained to 42.55% and 65.27% in MN2 lower than BN2 in both years. The yield increased with an increase in the basal fertilizer, top dressing and plastic film mulching, and the

  12. Long-term incorporation of manure with chemical fertilizers reduced total nitrogen loss in rain-fed cropping systems

    NASA Astrophysics Data System (ADS)

    Duan, Yinghua; Xu, Minggang; Gao, Suduan; Liu, Hua; Huang, Shaomin; Wang, Boren

    2016-09-01

    Improving soil fertility/productivity and reducing environmental impact of nitrogen (N) fertilization are essential for sustainable agriculture. Quantifying the contribution of various fertilization regimes to soil N storage and loss has been lacking in a wide range of spatiotemporal scales. Based on data collected from field experiments at three typical agricultural zones in China, soil N dynamics and N changes in soil profile (0–100 cm) were examined during 1990–2009 under chemical fertilization, manure incorporation with fertilizer, and fertilizer with straw return treatments. We employed a mass balance approach to estimate the N loss to the environment after taking into account soil N change. Results showed a significant increase in soil N storage under manure incorporation treatments, accompanied with the lowest N loss (ave.20–24% of total N input) compared to all other treatments (ave.35–63%). Both soil N distribution and mass balance data suggested higher leaching risk from chemical fertilization in acidic soil of southern China with higher precipitation than the other two sites. This research concludes that manure incorporation with chemical fertilizer not only can achieve high N use efficiency and improve soil fertility, but also leads to the lowest total N loss or damage to the environment.

  13. Long-term incorporation of manure with chemical fertilizers reduced total nitrogen loss in rain-fed cropping systems

    PubMed Central

    Duan, Yinghua; Xu, Minggang; Gao, Suduan; Liu, Hua; Huang, Shaomin; Wang, Boren

    2016-01-01

    Improving soil fertility/productivity and reducing environmental impact of nitrogen (N) fertilization are essential for sustainable agriculture. Quantifying the contribution of various fertilization regimes to soil N storage and loss has been lacking in a wide range of spatiotemporal scales. Based on data collected from field experiments at three typical agricultural zones in China, soil N dynamics and N changes in soil profile (0–100 cm) were examined during 1990–2009 under chemical fertilization, manure incorporation with fertilizer, and fertilizer with straw return treatments. We employed a mass balance approach to estimate the N loss to the environment after taking into account soil N change. Results showed a significant increase in soil N storage under manure incorporation treatments, accompanied with the lowest N loss (ave.20–24% of total N input) compared to all other treatments (ave.35–63%). Both soil N distribution and mass balance data suggested higher leaching risk from chemical fertilization in acidic soil of southern China with higher precipitation than the other two sites. This research concludes that manure incorporation with chemical fertilizer not only can achieve high N use efficiency and improve soil fertility, but also leads to the lowest total N loss or damage to the environment. PMID:27650801

  14. Near infrared reflectance measurement of nitrogen faecal losses.

    PubMed

    Benini, L; Caliari, S; Bonfante, F; Guidi, G C; Brentegani, M T; Castellani, G; Sembenini, C; Bardelli, E; Vantini, I

    1992-06-01

    Chemical methods of measuring nitrogen in stools are complex, unpleasant, and therefore rarely performed. Recently, near infrared reflectance (NIRA) has been suggested for stool analysis. The aim of this study was to evaluate the possible application of this method in routine faecal nitrogen measurement. Nitrogen concentration and daily output were measured in the stools of 83 patients using NIRA and, for comparison, the Kjeldahl method. Nitrogen concentration and output ranged between 0.4-2.72 g% and 0.45-8.96 g/day respectively. Correlation coefficients (r), of 0.89 and 0.97 were found between the two methods for concentration and output respectively, and similar values were found in patients on enteral nutrition. Repeated measurements from the same stool collection, requiring only a few minutes, allowed homogenisation to be avoided. NIRA seems to be an easy, fast, and reliable alternative to chemical assays of nitrogen measurement in the management of patients with digestive disorders.

  15. [Effect of DMPP on inorganic nitrogen runoff loss from vegetable soil].

    PubMed

    Yu, Qiao-Gang; Fu, Jian-Rong; Ma, Jun-Wei; Ye, Jing; Ye, Xue-Zhu

    2009-03-15

    The effect of urea with 1% 3,4-dimethyl pyrazole phosphate (DMPP) on inorganic nitrogen runoff loss from agriculture field was determined in an undisturbed vegetable soil by using the simulated artificial rainfall method. The results show that, during the three simulated artificial rainfall period, the ammonium nitrogen content in the runoff water is increased 1.42, 2.82 and 1.95 times with the DMPP application treatment compared to regular urea treatment, respectively. In the urea with DMPP addition treatment, the nitrate nitrogen content is decreased 70.2%, 59.7% and 52.1% in the three simulated artificial rainfall runoff water, respectively. The nitrite nitrogen content is also decreased 98.7%, 90.6% and 85.6% in the three simulated artificial rainfall runoff water, respectively. The nitrate nitrogen and nitrite nitrogen runoff loss are greatly declined with the DMPP addition in the urea. Especially the nitrite nitrogen is in a significant low level and is near to the treatment with no fertilizer application. The inorganic nitrogen runoff loss is declined by 39.0% to 44.8% in the urea with DMPP addition treatment. So DMPP could be used as an effective nitrification inhibitor to control the soil ammonium oxidation, decline the nitrogen runoff loss, lower the nitrogen transformation risk to the waterbody and be beneficial for the ecological environment.

  16. Influence of grassing targeted into the recharge zone on the nitrate concentrations and nitrogen leaching out of the drained catchment.

    NASA Astrophysics Data System (ADS)

    Zajíček, Antonín; Fučík, Petr; Kvítek, Tomáš

    2015-04-01

    Long term experiment with the land use change in tile drainage recharge zone was conducted in the catchment Dehtáře (57.9 ha, Bohemian-Moravian Highlands, Czech Republic). It is a locally typical small agricultural catchment, where the tile drainage acts as the only permanent runoff and the drainage system was built in the slope. Several drainage subsystems with various land use in their recharge and discharge zones has been monitored since 2003. Recharge zones of some subsystems were grassed since the hydrological year 2007 and nitrate concentrations, theirs trends and nitrogen loads were statistically analysed and compared with subsystems without the land use change. The statistical analysis showed that the flow-weighted nitrate concentrations before grassing the recharge zone were surprisingly higher in drainage subsystems with the permanent grassland in drained area (discharge zone) than in the subsystem under arable land. Approximately one year after grassing the recharge zone, the long-term course of NO3 concentrations became decreasing. The statistically significant decreases in nitrate concentrations of 32.1% and 25.7% were detected in drainage subsystems under the grassed recharge zone. In the same period, an increase in nitrate concentration was detected in sites without land use change. There was an increase of 10.8% in the drainage subsystem with arable land in both (recharge and discharge) zones and of 8.6% in the subsystem with grassland in the discharge zone, but arable land in the recharge zone. Evaluating the whole drainage system, the fall in nitrate concentrations by 10.5% was detected after grassing about 20% of this systems recharge zone. In association with the change in nitrate concentrations, the nitrate-nitrogen leaching decreased after grassing. In the scale of whole drainage system, the monthly average load decreased by 23% from 3.2 kg N/month/ha to 2.6 kg N/month/ha. In the drainage subsystem, where the recharge zone was grassed

  17. The effects of the African Green Revolution on nitrogen losses from two contrasting soil types in sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Tully, K. L.; Russo, T.; Hickman, J. E.; Palm, C.

    2013-12-01

    Nearly 80% of countries in sub-Saharan Africa (SSA) face problems of nitrogen (N) scarcity, which together with poverty causes food insecurity and malnutrition. The Alliance for a Green Revolution in Africa has set a goal of increasing fertilizer use in the region six-fold by 2015. While there is substantial evidence that greater N fertilizer use will improve crop yields, it could lead to increased N leaching and elevated nitrate (NO3-) concentrations in surface water and groundwater reservoirs. However, it is unclear what the magnitude of impacts will be in SSA given historically low nutrient additions (of less than 5 kg N/ha/yr), highly degraded soils (due to years of nutrient and soil organic matter depletion), and a wide range of soil types on which increased fertilizer use is occurring. Current estimates of N dynamics and balances in SSA agriculture now rely on data from other regions with different soil types, soil fertility, and land management practices. To understand the influence of increased fertilizer use on water quality requires data from representative areas in SSA. Experimental maize plots were established in a randomized complete block design in both western Kenya (clayey soil) and mid-western Tanzania (sandy soil). Plots were amended with 0, 50, 75, and 200 kg N/ha/yr as mineral fertilizer. Tension lysimeters were installed at three depths in each treatment, and water was collected throughout the maize growing season. Soil water solutions were analyzed for NO3--N. Flow through the soil column at each soil depth, was modeled using VS2DT, a variably saturated flow and solute transport model, and water flux values were multiplied by measured NO3--N concentrations to estimate seasonal N leaching flux. Soil texture was a major driver of N losses, altering both the pathways and magnitude of losses. Clayey soils in western Kenya show an enormous potential for loss of NO3--N immediately following the onset of rains as they trigger high rates of N

  18. Manure incorporation reduces environmental nitrogen loss while sustaining crop productivity in the subtropical wheat-maize rotation system: A comprehensive study of nitrogen cycling and balance

    NASA Astrophysics Data System (ADS)

    Zhou, Minghua; Zhu, Bo; Butterbach-Bahl, klaus; Brüggemann, Nicolas

    2016-04-01

    Balancing nitrogen (N) budgets of agricultural systems is essential for sustaining yields at lower environmental costs. The knowledge, however, of total N budgets of agricultural systems including all N fluxes is still rare in the literature. Here, we applied a combination of monitoring in situ N fluxes and field 15N tracer and 15N isotope dilution techniques to investigate the effects of different N fertilizers (control, synthetic fertilizer, 60% synthetic fertilizer N plus 40% pig manure N, pig manure only applied at the same N rate 280 kg N ha-1 yr-1) on N pools, cycling processes, fluxes and total N balances in a subtropical wheat-maize rotation system of China. Nitrate leaching and NH3 volatilization were main hydrological and gaseous N loss pathways, respectively. The warm and wet maize season was associated with significantly larger environmental N losses than the cooler and drier wheat season. The field 15N tracing experiment showed that the wheat system had high N retention capacity (˜50% of 15N application) but with short residence time. I.e. 90% of soil residual 15N labelled fertilizer in the wheat system were utilized by plants or lost to the environment in the subsequent maize season. Our annual total N balances of the different treatments revealed that combined synthetic and organic fertilization or manure only maintained the same level of yields and led to significantly lower N losses and higher N retention, even though larger NH3 volatilization losses were caused by manure incorporation. Thus, our study suggests that a combination of synthetic and organic N fertilizers is suitable for sustaining agricultural productivity while reducing environmental N losses through fostering interactions between the soil C and N cycle.

  19. Assessment of drainage nitrogen losses on a yield-scaled basis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Subsurface nitrogen (N) losses represent a major environmental concern in agriculture, particularly from fields containing artificial drainage to prevent saturated soil conditions and increase crop production. To develop sustainable intensification strategies and achieve high yields with minimal en...

  20. Nitrogen loss from windblown agricultural soils in the Columbia Plateau

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind erosion of agricultural soils can degrade both air quality and soil productivity in the Columbia Plateau of the Pacific Northwest United States. Soils in the region contain fine particles that, when suspended, are highly susceptible to long range transport in the atmosphere. Nitrogen (N) associ...

  1. Nitrogen catch crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High costs of nitrogen (N) fertilizer and the potential for N losses to ground and surface water have resulted in increased interest in using catch crops to recover this N. Research on potatoes has shown that the amount of N lost to leaching can be as much as the amount of N removed from the field ...

  2. Enhanced Nitrogen Loss by Eddy-Induced Vertical Transport in the Offshore Peruvian Oxygen Minimum Zone.

    PubMed

    Callbeck, Cameron M; Lavik, Gaute; Stramma, Lothar; Kuypers, Marcel M M; Bristow, Laura A

    2017-01-01

    The eastern tropical South Pacific (ETSP) upwelling region is one of the ocean's largest sinks of fixed nitrogen, which is lost as N2 via the anaerobic processes of anammox and denitrification. One-third of nitrogen loss occurs in productive shelf waters stimulated by organic matter export as a result of eastern boundary upwelling. Offshore, nitrogen loss rates are lower, but due to its sheer size this area accounts for ~70% of ETSP nitrogen loss. How nitrogen loss and primary production are regulated in the offshore ETSP region where coastal upwelling is less influential remains unclear. Mesoscale eddies, ubiquitous in the ETSP region, have been suggested to enhance vertical nutrient transport and thereby regulate primary productivity and hence organic matter export. Here, we investigated the impact of mesoscale eddies on anammox and denitrification activity using 15N-labelled in situ incubation experiments. Anammox was shown to be the dominant nitrogen loss process, but varied across the eddy, whereas denitrification was below detection at all stations. Anammox rates at the eddy periphery were greater than at the center. Similarly, depth-integrated chlorophyll paralleled anammox activity, increasing at the periphery relative to the eddy center; suggestive of enhanced organic matter export along the periphery supporting nitrogen loss. This can be attributed to enhanced vertical nutrient transport caused by an eddy-driven submesoscale mechanism operating at the eddy periphery. In the ETSP region, the widespread distribution of eddies and the large heterogeneity observed in anammox rates from a compilation of stations suggests that eddy-driven vertical nutrient transport may regulate offshore primary production and thereby nitrogen loss.

  3. Enhanced Nitrogen Loss by Eddy-Induced Vertical Transport in the Offshore Peruvian Oxygen Minimum Zone

    PubMed Central

    Callbeck, Cameron M.; Lavik, Gaute; Stramma, Lothar; Kuypers, Marcel M. M.; Bristow, Laura A.

    2017-01-01

    The eastern tropical South Pacific (ETSP) upwelling region is one of the ocean’s largest sinks of fixed nitrogen, which is lost as N2 via the anaerobic processes of anammox and denitrification. One-third of nitrogen loss occurs in productive shelf waters stimulated by organic matter export as a result of eastern boundary upwelling. Offshore, nitrogen loss rates are lower, but due to its sheer size this area accounts for ~70% of ETSP nitrogen loss. How nitrogen loss and primary production are regulated in the offshore ETSP region where coastal upwelling is less influential remains unclear. Mesoscale eddies, ubiquitous in the ETSP region, have been suggested to enhance vertical nutrient transport and thereby regulate primary productivity and hence organic matter export. Here, we investigated the impact of mesoscale eddies on anammox and denitrification activity using 15N-labelled in situ incubation experiments. Anammox was shown to be the dominant nitrogen loss process, but varied across the eddy, whereas denitrification was below detection at all stations. Anammox rates at the eddy periphery were greater than at the center. Similarly, depth-integrated chlorophyll paralleled anammox activity, increasing at the periphery relative to the eddy center; suggestive of enhanced organic matter export along the periphery supporting nitrogen loss. This can be attributed to enhanced vertical nutrient transport caused by an eddy-driven submesoscale mechanism operating at the eddy periphery. In the ETSP region, the widespread distribution of eddies and the large heterogeneity observed in anammox rates from a compilation of stations suggests that eddy-driven vertical nutrient transport may regulate offshore primary production and thereby nitrogen loss. PMID:28122044

  4. Organic Matter Loading Modifies the Microbial Community Responsible for Nitrogen Loss in Estuarine Sediments.

    PubMed

    Babbin, Andrew R; Jayakumar, Amal; Ward, Bess B

    2016-04-01

    Coastal marine sediments, as locations of substantial fixed nitrogen loss, are very important to the nitrogen budget and to the primary productivity of the oceans. Coastal sediment systems are also highly dynamic and subject to periodic natural and anthropogenic organic substrate additions. The response to organic matter by the microbial community involved in nitrogen loss processes was evaluated using mesocosms of Chesapeake Bay sediments. Over the course of a 50-day incubation, rates of anammox and denitrification were measured weekly using (15)N tracer incubations, and samples were collected for genetic analysis. Rates of both nitrogen loss processes and gene abundances associated with them corresponded loosely, probably because heterogeneities in sediments obscured a clear relationship. The rates of denitrification were stimulated more, and the fraction of nitrogen loss attributed to anammox slightly reduced, by the higher organic matter addition. Furthermore, the large organic matter pulse drove a significant and rapid shift in the denitrifier community composition as determined using a nirS microarray, indicating that the diversity of these organisms plays an essential role in responding to anthropogenic inputs. We also suggest that the proportion of nitrogen loss due to anammox in these coastal estuarine sediments may be underestimated due to temporal dynamics as well as from methodological artifacts related to conventional sediment slurry incubation approaches.

  5. Dissolved nitrogen, chloride, and potassium loss from fields in conventional and conservation tillage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Losses of soluble nutrients from cropland and their transport to surface and groundwater are a continuing water quality concern. In this study we evaluated tillage impact on dissolved losses of ammonium (NH4-N) and nitrate nitrogen (NO3-N), chloride (Cl), and potassium (K) during rotational cotton ...

  6. Nitrogen Accumulation and Changes in Nitrate Leaching After Four Years of Intensive Forest Culture on Marginal Agricultural Land

    SciTech Connect

    Williams, T.M.; Gresham, C.A.

    2000-02-15

    Loblolly pine and sweetgum were grown with irrigation, continuous fertilizer application and insect pest control on a year old abandoned peanut field. Wells and tension lysimeters were used to measure nitrate-nitrogen in soil moisture and groundwater on three replicate transects for four years. Years 1 and 2, groundwater nitrate-nitrogen concentration exceeded drinking water standards. Years 3 and 4, groundwater nitrate-nitrogen concentration decreased where the greatest reduction occurred in soil moisture at the shallowest depths.

  7. The study of aluminum loss and consequent phase transformation in heat-treated acid-leached kaolin

    SciTech Connect

    Foo, Choo Thye; Mahmood, Che Seman; Mohd Salleh, Mohamad Amran

    2011-04-15

    This study investigates the effect of Al leaching during Fe removal from kaolin to mullite. Heat-treated kaolin was obtained by heating natural kaolin at 400, 500, 600, 700, 800 and 900 deg. C. The heat-treated kaolin was then leached at 100 deg. C with 4 M, 3 M, 2 M, 1 M, 0.2 M solution of H{sub 2}SO{sub 4} and 0.2 M solution of oxalic acid. The dried samples were sintered to 1300 deg. C for 4 h at a heating rate of 10 deg. C min{sup -1}. X-ray diffractometry and differential thermal analysis were used to study the phase transformation of kaolin to mullite. It was found that 700 deg. C is the optimum preheat-treatment temperature to leach out Fe and also Al for both types of the acids used. The majority of the 4 M sulfuric acid-treated kaolins formed the cristobalite phase when sintered. On the other hand, 1 M, 0.2 M sulfuric acid and 0.2 M oxalic acid leached heat-treated kaolin formed mullite and quartz phase after sintering. - Research Highlights: {yields} Preheat-treatment of kaolin improves the leachability of unwanted iron. {yields} The optimum preheat-treatment temperature is 700 deg. C. {yields} Sintered 4 M sulfuric acid-treated kaolin majorly formed the cristobalite phase. {yields} Sintered 0.2 M oxalic acid-treated kaolin formed lesser amorphous silicate phase.

  8. Evaluation of Poultry Litter Amendment to Agricultural Soils: Leaching Losses and Partitioning of Trace Elements in Collard Greens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaching of trace metals and greenhouse plant growth (Collard greens; Brassica oleracea var. acephala) response studies were conducted in two types of soils with contrasting characteristics amended with varying rates (0 to 24.70 Mg ha-1) of poultry litter (PL) or 1:1 mixture of PL and fly ash (FA). ...

  9. [Temporal and spatial distribution characteristics of nitrogen losses in hilly area of Taihu Lake].

    PubMed

    Wang, Peng; Gao, Chao; Yao, Qi; Han, Long-Xi; Shen, Xia

    2006-08-01

    Four typical land uses in hilly area of Taihu Lake were studied on temporal and spatial distribution characteristics of nitrogen losses in surface runoff under natural rainfall through experiment in situ. The medium value of event mean concentration (EMC) of ammonia nitrogen (NH4(+) -N) which dominated agricultural N in surface runoff accounted for 44.5% of total nitrogen (TN), while nitrite nitrogen (NO2(-) -N) accounted for 1.8%. Concentration of nitrogen in runoff had significantly seasonal variation which was related to meteorologic conditions such as rainfall, temperature, and agricultural activities. Temporal variabilities of site mean concentration (SMC) for TN, NH4(+) -N, NO3(-) -N and NO2(-) -N were decreased sequentially. The highest SMC value of TN, NH(+) -N and NO3(-) -N in upland runoff and N2(-) -N in bamboo grove were observed. The spatial distribution of nitrogen losses was determined by fertilizer application and vegetation coverage. Spatial variabilities for SMC of nitrogen were less than temporal variabilities. It was found that transportation fluxes of nitrogen in surface runoff from upland and vegetable plot were higher than that from chestnut orchard and bamboo forest which have significantly related to surface runoff volume.

  10. The nitrogen index as a tool to reduce nitrogen loss to the environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continued population growth creates a need for increased productivity of agricultural systems around the world. Increased agricultural productivity will be needed to support a population that is anticipated to have an additional 2.5 billion people by the year 2050. Nitrogen was part of the 20th cent...

  11. Surface runoff and nitrogen (N) loss in a bamboo (Phyllostachys pubescens) forest under different fertilization regimes.

    PubMed

    Zhang, Qichun; Shamsi, Imran Haider; Wang, Jinwen; Song, Qiujin; Xue, Qiaoyun; Yu, Yan; Lin, Xianyong; Hussain, Sayed

    2013-07-01

    Nitrogen (N) losses from agricultural fields have been extensively studied. In contrast, surface runoff and N losses have rarely been considered for bamboo forests that are widespread in regions such as southern China. The thriving of bamboo industries has led to increasing fertilizer use in bamboo forests. In this study, we evaluated surface runoff and N losses in runoff following different fertilization treatments under field conditions in a bamboo (Phyllostachys pubescens) forest in the catchment of Lake Taihu in Jiangsu, China. Under three different fertilization regimes, i.e., control, site-specific nutrient management (SSNM), and farmer's fertilization practice (FFP), the water runoff rate amounted to 356, 361, and 342 m(3) ha(-1) and accounted for 1.91, 1.98, and 1.85% of the water input, respectively, from June 2009 to May 2010. The total N losses via surface runoff ranged from 1.2 to 1.8 kg ha(-1). Compared with FFP, the SSNM treatment reduced total nitrogen (TN) and dissolved nitrogen (DN) losses by 31 and 34%, respectively. The results also showed that variations in N losses depended mainly on runoff fluxes, not N concentrations. Runoff samples collected from all treatments throughout the year showed TN concentrations greater than 0.35 mg L(-1), with the mean TN concentration in the runoff from the FFP treatment reaching 8.97 mg L(-1). The loss of NO3(-)-N was greater than the loss of NH4(+)-N. The total loss of dissolved organic nitrogen (DON) reached 23-41% of the corresponding DN. Therefore, DON is likely the main N species in runoff from bamboo forests and should be emphasized in the assessment and management of N losses in bamboo forest.

  12. Nitrogen loss by anaerobic oxidation of ammonium in rice rhizosphere

    PubMed Central

    Nie, San'an; Li, Hu; Yang, Xiaoru; Zhang, Zhaoji; Weng, Bosen; Huang, Fuyi; Zhu, Gui-Bing; Zhu, Yong-Guan

    2015-01-01

    Anaerobic oxidation of ammonium (anammox) is recognized as an important process for nitrogen (N) cycling, yet its role in agricultural ecosystems, which are intensively fertilized, remains unclear. In this study, we investigated the presence, activity, functional gene abundance and role of anammox bacteria in rhizosphere and non-rhizosphere paddy soils using catalyzed reporter deposition–fluorescence in situ hybridization, isotope-tracing technique, quantitative PCR assay and 16S rRNA gene clone libraries. Results showed that rhizosphere anammox contributed to 31–41% N2 production with activities of 0.33–0.64 nmol N2 g−1 soil h−1, whereas the non-rhizosphere anammox bacteria contributed to only 2–3% N2 production with lower activities of 0.08–0.26 nmol N2 g−1 soil h−1. Higher anammox bacterial cells were observed (0.75–1.4 × 107 copies g−1 soil) in the rhizosphere, which were twofold higher compared with the non-rhizosphere soil (3.7–5.9 × 106 copies g−1 soil). Phylogenetic analysis of the anammox bacterial 16S rRNA genes indicated that two genera of ‘Candidatus Kuenenia' and ‘Candidatus Brocadia' and the family of Planctomycetaceae were identified. We suggest the rhizosphere provides a favorable niche for anammox bacteria, which are important to N cycling, but were previously largely overlooked. PMID:25689022

  13. Long-term effects of clear cutting and intensive biomass harvesting on the nitrogen leaching to groundwater in the boreal forest environment

    NASA Astrophysics Data System (ADS)

    Kubin, Eero

    2013-04-01

    Clear-cutting and site preparation cause the greatest changes in site conditions and to the environment. The oldest research carried out within the boreal coniferous forest zone on the leaching of nutrients into watercourses was conducted in Sweden in the early 1970s. Also in Finland, the effect of clear-cutting and site preparation on the quality of surface runoff has been monitored since 1974 and into the groundwater, after waste wood harvesting, since 1986. Recently intensive biomass harvest has been rapidly increasing and nowadays about seven percent of the total consumption of energy in Finland comes from forest energy. The consumption derived from wood-based fuels is as much as 23 per cent of the total energy. Thus study and understanding forest ecosystems function is nowadays facing new challenges, especially when harvested forest energy, especially stumps, course disturbances and more water penetrating into the soil and groundwater in addition to other ecosystem changes. According the long term-monitoring results nitrate nitrogen seems to be the foremost nutrient leached into the groundwater as a consequence of forestry operations. The effects of clear-cutting on nitrate nitrogen leaching and concentrations in surface water have been shown to last only a few years, but the long-term property of increasing groundwater concentrations, have persisted 25 years which has not reported earlier from other sites. Clear-cutting increases the input of precipitation, but in northern areas this cannot be the main reason for the higher values. The greater part of the increased concentrations is due to the decomposition of cutting waste and humus. This is interesting in relation to intensive biomass harvesting. The availability and the quality of water are strongly influenced by forests. The relationship between forests and water is therefore a critical issue that must be accorded high priority also when developing forest biomass harvesting for energy. To develop best

  14. Where did all the Nitrogen go? Use of Watershed-Scale Budgets to Quantify Nitrogen Inputs, Storages, and Losses.

    NASA Astrophysics Data System (ADS)

    Boyer, E. W.; Goodale, C. L.; Howarth, R. W.; VanBreemen, N.

    2001-12-01

    Inputs of nitrogen (N) to aquatic and terrestrial ecosystems have increased during recent decades, primarily from the production and use of fertilizers, the planting of N-fixing crops, and the combustion of fossil fuels. We present mass-balanced budgets of N for 16 catchments along a latitudinal profile from Maine to Virginia, which encompass a range of climatic variability and are major drainages to the coast of the North Atlantic Ocean. We quantify inputs of N to each catchment from atmospheric deposition, application of nitrogenous fertilizers, biological nitrogen fixation by crops and trees, and import of N in agricultural products (food and feed). We relate these input terms to losses of N (total, organic, and nitrate) in streamflow. The importance of the relative N sources to N exports varies widely by watershed and is related to land use. Atmospheric deposition was the largest source of N to the forested catchments of northern New England (e.g., Penobscot and Kennebec); import of N in food was the largest source of N to the more populated regions of southern New England (e.g., Charles and Blackstone); and agricultural inputs were the dominant N sources in the Mid-Atlantic region (e.g., Schuylkill and Potomac). In all catchments, N inputs greatly exceed outputs, implying additional loss terms (e.g., denitrification or volatilization and transport of animal wastes), or changes in internal N stores (e.g, accumulation of N in vegetation, soil, or groundwater). We use our N budgets and several modeling approaches to constrain estimates about the fate of this excess N, including estimates of N storage in accumulating woody biomass, N losses due to in-stream denitrification, and more. This work is an effort of the SCOPE Nitrogen Project.

  15. Reducing nitrogen loss with managed drainage and polymer-coated urea.

    PubMed

    Nash, Patrick; Nelson, Kelly; Motavalli, Peter

    2015-01-01

    Continuous corn ( L.) production during dry years combined with high N fertilizer rates can have a high potential for NO-N loss through tile drainage water. Claypan soils can further increase the potential for NO-N loss through tile drainage water due to the claypan layer that restricts N leaching below the tile drains. The objective of this 4-yr study was to determine whether use of managed subsurface drainage (MD) in combination with a controlled-release N fertilizer could reduce the annual amount of NO-N loss through tile drainage water compared with free subsurface tile drainage (FD) with a noncoated urea application. Due to dry conditions over the summer and fall months, MD reduced the annual amount of water drained by at least 73% compared with FD in two of the four crop years. Low N loss and reduced corn N uptake possibly resulted in carry-over N and high soil N concentrations throughout the study, which may have limited the effect of N fertilizer source on annual NO-N loss in the tile drainage water. Use of MD reduced annual NO-N loss in the tile drainage water by 78 to 85% in two of the four years. High NO-N loss reduction with MD compared with FD was largely due to dry growing season conditions in combination with wet conditions over the noncropping period.

  16. Nitrogen mineralization and gaseous nitrogen losses from waterlogged and drained organic soils in a black alder (Alnus glutinosa (L.) Gaertn.) forest

    NASA Astrophysics Data System (ADS)

    Eickenscheidt, T.; Heinichen, J.; Augustin, J.; Freibauer, A.; Drösler, M.

    2014-06-01

    Black alder (Alnus glutinosa (L.) Gaertn.) forests on peat soils have been reported to be hotspots for high nitrous oxide (N2O) losses. High emissions may be attributed to alternating water tables of peatlands and to the incorporation of high amounts of easily decomposable nitrogen (N) into the ecosystem by symbiotic dinitrogen (N2)-fixation of alder trees. Our study addressed the question to what extent drainage enhances the emissions of N2O from black alder forests and how N turnover processes and physical factors influence the production of N2O and total denitrification. The study was conducted in a drained black alder forest with variable groundwater tables at a southern German fen peatland. Fluxes of N2O were measured using the closed chamber method at two drained sites (D-1 and D-2) and one undrained site (U). Inorganic N contents and net N mineralization rates (NNM) were determined. Additionally a laboratory incubation experiment was carried out to investigate greenhouse gas and N2 fluxes at different temperature and soil moisture conditions. Significantly different inorganic N contents and NNM rates were observed, which however did not result in significantly different N2O fluxes in the field but did in the laboratory experiment. N2O fluxes measured were low for all sites, with total annual emissions of 0.51 ± 0.07 (U), 0.97 ± 0.13 (D-1) and 0.93 ± 0.08 kg N2O-N ha-1 yr-1 (D-2). Only 37% of the spatiotemporal variation in field N2O fluxes could be explained by peat temperature and groundwater level, demonstrating the complex interlinking of the controlling factors for N2O emissions. However, temperature was one of the key variables of N2O fluxes in the incubation experiment conducted. Increasing soil moisture content was found to enhance total denitrification losses during the incubation experiment, whereas N2O fluxes remained constant. At the undrained site, permanently high groundwater level was found to prevent net nitrification, resulting in a

  17. Nitrogen losses from dairy manure estimated through nitrogen mass balance and chemical markers

    USGS Publications Warehouse

    Hristov, Alexander N.; Zaman, S.; Vander Pol, M.; Ndegwa, P.; Campbell, L.; Silva, S.

    2009-01-01

    Ammonia is an important air and water pollutant, but the spatial variation in its concentrations presents technical difficulties in accurate determination of ammonia emissions from animal feeding operations. The objectives of this study were to investigate the relationship between ammonia volatilization and ??15N of dairy manure and the feasibility of estimating ammonia losses from a dairy facility using chemical markers. In Exp. 1, the N/P ratio in manure decreased by 30% in 14 d as cumulative ammonia losses increased exponentially. Delta 15N of manure increased throughout the course of the experiment and ??15N of emitted ammonia increased (p < 0.001) quadratically from -31??? to -15 ???. The relationship between cumulative ammonia losses and ??15N of manure was highly significant (p < 0.001; r2 = 0.76). In Exp. 2, using a mass balance approach, approximately half of the N excreted by dairy cows (Bos taurus) could not be accounted for in 24 h. Using N/P and N/K ratios in fresh and 24-h manure, an estimated 0.55 and 0.34 (respectively) of the N excreted with feces and urine could not be accounted for. This study demonstrated that chemical markers (P, K) can be successfully used to estimate ammonia losses from cattle manure. The relationship between manure ??15N and cumulative ammonia loss may also be useful for estimating ammonia losses. Although promising, the latter approach needs to be further studied and verified in various experimental conditions and in the field. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  18. A comparison of dissolved inorganic nitrogen, chloride and potassium loss in conventional and conservation tillage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage impact on dissolved losses of ammonium (NH4-N) and nitrate nitrogen (NO3-N), chloride (Cl), and potassium (K) during rotational cotton and peanut production was evaluated. Tillage treatments were strip-tillage (ST) and conventional-tillage (CT). Winter cover crops were used in both tillage...

  19. Chemical and isotopic tracers illustrate pathways of nitrogen loss in a cranberry bed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Limited research exists on the hydrological processes driving nitrogen (N) loss from cranberry production, which has been identified as a prominent source of watershed N loading in southeastern Massachusetts (MA). To quantify the hydrological processes underlying N export in cranberry farms, the geo...

  20. Simulation processes for the nitrogen loss and environmental assessment package (NLEAP).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Nitrogen Loss and Environmental Assessment Package model with Geographic Information System (GIS) (NLEAP-GIS) has been updated to include a MS Windows© user interface and simulation code refinements for surface residue decay, N2O soil gas emissions, crop rooting, multiple simultaneous simulatio...

  1. Fragipan controls on nitrogen loss by surface and subsurface flow pathways in an upland agricultural watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improved understanding of nutrient transport by surface and subsurface flow pathways is critical to protecting water quality in agricultural watersheds. We sought to compare nitrogen loss in overland and subsurface flow on two opposing hillslopes (north versus south facing), each with contrasting so...

  2. Soil temperature regulates nitrogen loss from lysimeters following fall and winter manure application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many producers practice fall and winter manure spreading for economic and practical reasons. In order to minimize the risk of nitrogen loss between application and crop uptake in the spring, university extension publications and industry professionals often make recommendations based on soil tempera...

  3. Riverine nitrogen loss in the Tibetan Plateau and potential impacts of climate change.

    PubMed

    Tong, Yindong; Chen, Long; Chi, Jie; Zhen, Gengchong; Zhang, Qianggong; Wang, Ruonan; Yao, Ruihua; Zhang, Wei; Wang, Xuejun

    2016-05-15

    The Tibetan Plateau (TP) has been the subject of study on water circulation and global climate change. Given the environmental processes related to water outflows, there could be massive nutrient losses in the land surface of TP. In this study, we analyzed the nitrogen discharges of the major rivers flowing out of the TP based on the 5-year monitoring data. According to our calculation, the majority of nitrogen outflows were discharged through the upper Yangtze River and upper Huanghe River, representing ~29% and ~17% of total riverine outflows, respectively. In the entire nitrogen deficit in TP land surface, about 2.7 × 10(5)Mg/year was lost through riverine discharges. Due to the global warming, the changes of hydrologic processes in TP would possibly accelerate the riverine nitrogen outflows in the future.

  4. Controlling the Hydrolysis and Loss of Nitrogen Fertilizer (Urea) by using a Nanocomposite Favors Plant Growth.

    PubMed

    Zhou, Linglin; Zhao, Pan; Chi, Yu; Wang, Dongfang; Wang, Pan; Liu, Ning; Cai, Dongqing; Wu, Zhengyan; Zhong, Naiqin

    2017-03-10

    Urea tends to be hydrolyzed by urease and then migrate into the environment, which results in a low utilization efficiency and severe environmental contamination. To solve this problem, a network-structured nanocomposite (sodium humate-attapulgite-polyacrylamide) was fabricated and used as an excellent fertilizer synergist (FS) that could effectively inhibit the hydrolysis, reduce the loss, and enhance the utilization efficiency of nitrogen. Additionally, the FS exerted significant positive effects on the expression of several nitrogen-uptake-related genes, ion flux in maize roots, the growth of crops, and the organic matter in soil. The FS could modify the microbial community in the soil and increase the number of bacteria involved in nitrogen metabolism, organic matter degradation, the iron cycle, and photosynthesis. Importantly, this technology displayed a high biosafety and has a great potential to reduce nonpoint agricultural pollution. Therefore, this work provides a promising approach to manage nitrogen and to promote the sustainable development of agriculture and the environment.

  5. [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.

  6. First approach to the Japanese nitrogen footprint model to predict the loss of nitrogen to the environment

    NASA Astrophysics Data System (ADS)

    Shibata, Hideaki; Cattaneo, Lia R.; Leach, Allison M.; Galloway, James N.

    2014-11-01

    Humans increase the amount of reactive nitrogen (all N species except N2) in the environment through a number of processes, primarily food and energy production. Once in the environment, excess reactive nitrogen may cause a host of various environmental problems. Understanding and controlling individual nitrogen footprints is important for preserving environmental and human health. In this paper we present the per capita nitrogen footprint of Japan. We considered the effect of the international trade of food and feed, and the impact of dietary preferences among different consumer age groups. Our results indicate that the current average per capita N footprint in Japan considering trade is 28.1 kg N capita-1 yr-1. This footprint is dominated by food (25.6 kg N capita-1 yr-1), with the remainder coming from the housing, transportation, and goods and services sectors. The difference in food choices and intake between age groups strongly affected the food N footprint. Younger age groups tend to consume more meat and less fish, which leads to a larger food N footprint (e.g., 27.5 kg N capita-1 yr-1 for ages 20 to 29) than for older age groups (e.g., 23.0 kg N capita-1 yr-1 for ages over 70). The consideration of food and feed imports to Japan reduced the per capita N footprint from 37.0 kg N capita-1 yr-1 to 28.1 kg N capita-1 yr-1. The majority of the imported food had lower virtual N factors (i.e., Nr loss factors for food production), indicating that less N is released to the environment during the respective food production processes. Since Japan relies on imported food (ca. 61%) more than food produced domestically, much of the N losses associated with the food products is released in exporting countries.

  7. Global assessment of nitrogen losses and trade-offs with yields from major crop cultivations.

    PubMed

    Liu, Wenfeng; Yang, Hong; Liu, Junguo; Azevedo, Ligia B; Wang, Xiuying; Xu, Zongxue; Abbaspour, Karim C; Schulin, Rainer

    2016-12-01

    Agricultural application of reactive nitrogen (N) for fertilization is a cause of massive negative environmental problems on a global scale. However, spatially explicit and crop-specific information on global N losses into the environment and knowledge of trade-offs between N losses and crop yields are largely lacking. We use a crop growth model, Python-based Environmental Policy Integrated Climate (PEPIC), to determine global N losses from three major food crops: maize, rice, and wheat. Simulated total N losses into the environment (including water and atmosphere) are 44TgNyr(-1). Two thirds of these, or 29TgNyr(-1), are losses to water alone. Rice accounts for the highest N losses, followed by wheat and maize. The N loss intensity (NLI), defined as N losses per unit of yield, is used to address trade-offs between N losses and crop yields. The NLI presents high variation among different countries, indicating diverse N losses to produce the same amount of yields. Simulations of mitigation scenarios indicate that redistributing global N inputs and improving N management could significantly abate N losses and at the same time even increase yields without any additional total N inputs.

  8. Effect of scraping frequency in a freestall barn on volatile nitrogen loss from dairy manure.

    PubMed

    Moreira, V R; Satter, L D

    2006-07-01

    The objective of this investigation was to evaluate the effect of scraping frequency (2x vs. 6x daily) on N volatilization from manure on the floor of a dairy free-stall barn. Three trials (crossover design) were conducted in the summers of 2001 and 2002, and in the winter of 2003. Nitrogen volatilization was estimated from the change in the N:P ratio in excreta at the time of excretion to the time when manure was scraped from the barn. Total N loss was considered a maximum estimate of NH3-N loss, because small amounts of nonammonia N may be volatilized. Nitrogen was determined after manure subsamples were lyophilized; P content was measured by direct current emission spectroscopy of ashed subsamples of manure. Lactating dairy cows were fed high-protein (18.5 to 19.3% crude protein), alfalfa-based diets. Average milk yield was 31.9 (SD = 7.4) kg/d. Scraping frequency had no effect on N loss in summer 2001. An average of 41% of excreted N, or 238 +/- 19.0 g of N/d per cow, was volatilized. For the trial in summer 2002, nitrogen volatilization was reduced from 50% of the excreted N with 2x to 46.7% with 6x, equivalent to 265 and 248 g of N lost/d per cow, respectively. Scraping had no effect on N volatilization during the winter trial. An average of 17.7% of excreted N was volatilized during the winter, equivalent to 109 +/- 11.0 g of N lost/d per cow. Scraping frequency of manure had little or no effect on N loss from manure in a freestall barn. Nitrogen loss during the winter was less than half of the loss during the summer.

  9. Sediment-bound total organic carbon and total organic nitrogen losses from conventional and strip tillage cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erosion and sediment loss with runoff are closely linked to global carbon and nitrogen cycles. Reducing tillage has been shown to reduce erosion and runoff sediment-bound carbon (C) and nitrogen (N) losses. However, published studies represent only a few soil types and regions and rarely direct...

  10. Massive nitrogen loss in critical surgical illness: effect on cardiac mass and function.

    PubMed Central

    Hill, A A; Plank, L D; Finn, P J; Whalley, G A; Sharpe, N; Clark, M A; Hill, G L

    1997-01-01

    OBJECTIVE: The authors measured cardiac mass and function to determine whether these changed in patients who were critically ill who were losing large amounts of nitrogen from the body. SUMMARY BACKGROUND DATA: The large losses of body nitrogen that occur in patients with protein-energy malnutrition are associated with a loss of cardiac mass and function. It is not known if this also occurs in patients who were critically ill who are losing massive amounts of nitrogen. METHODS: Once hemodynamically stable, 13 patients who were critically ill underwent sequential measurements of left ventricular mass (LVM) and function, total body nitrogen (TBN), total body potassium, body weight, fat-free mass, and limb muscle mass. RESULTS: Over a 21-day study period, there was no change in LVM or function despite falls of 14% and 21% in TBN and total body potassium, respectively, a 21% fall in limb muscle mass, and a deterioration in skeletal muscle function by approximately 40%. CONCLUSIONS: In patients who were critically ill, cardiac mass does not decrease and function does not deteriorate after hemodynamic stability has been achieved despite massive losses of protein from the body. PMID:9296513

  11. Effects of AN Alfalfa (medicago Sativa) Buffer Strip on Leached δ15NNITRATE Values: Implications for Management of Hydrologic N Losses

    NASA Astrophysics Data System (ADS)

    Kelley, C. J.; Keller, C. K.; Smith, J. L.; Evans, R. D.; Harlow, B.

    2011-12-01

    Buffer strips are commonly used to decrease agricultural runoff with the objective of limiting sediment and agrochemicals fluxes to surface waters. The objective of this study was to determine the effects of an alfalfa buffer strip on the magnitude and source(s) of leached nitrate from a dryland agricultural field. Previous research at the Cook Agronomy Farm has inferred two sources of nitrate in tile drain discharge, a high-discharge-season (January through May) synthetic fertilizer source, and a low-discharge-season (June through December) soil organic nitrogen source. This study examines how a change in management strategy and crop species alters the low discharge season nitrate source. In the spring of 2006 an alfalfa buffer strip approximately 20 m wide was planted running approximately north-south in the lowland portion of a 12 ha tile-drained field bordering a ditch that drains into Missouri Flat Creek. Three-year (2003 through 2005) average NO3--N flux prior to the planting of the alfalfa buffer strip was ~0.40 kg ha-1 year-1. After planting, the three-year (2006 through 2008) average NO3--N flux was ~0.38 kg ha-1 year-1. The lack of evident buffer-strip influence on the fluxes may be due in part to the large variation in precipitation amounts and timing that control water flows through the system. Three-year average δ15Nnitrate values for the tile drain pre and post planting of the alfalfa buffer strip were 6.9 ± 1.1 % and 4.2 ± 0.9 % respectively. We hypothesize that the significant difference indicates that the alfalfa strip affects the source of leached nitrate. Before planting the alfalfa buffer strip, the interpreted source of nitrate was mineralization of soil organic nitrogen from non-N2 fixing crops (spring and summer wheat varieties). After planting the alfalfa buffer strip, the source of nitrate was interpreted to be a mixture of mineralized soil organic nitrogen from N2 fixing alfalfa and non-N2 fixing crops. Further work is needed to test

  12. [Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

    PubMed

    Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

    2015-07-01

    Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff.

  13. Denitrification as the dominant nitrogen loss process in the Arabian Sea.

    PubMed

    Ward, B B; Devol, A H; Rich, J J; Chang, B X; Bulow, S E; Naik, Hema; Pratihary, Anil; Jayakumar, A

    2009-09-03

    Primary production in over half of the world's oceans is limited by fixed nitrogen availability. The main loss term from the fixed nitrogen inventory is the production of dinitrogen gas (N(2)) by heterotrophic denitrification or the more recently discovered autotrophic process, anaerobic ammonia oxidation (anammox). Oceanic oxygen minimum zones (OMZ) are responsible for about 35% of oceanic N(2) production and up to half of that occurs in the Arabian Sea. Although denitrification was long thought to be the only loss term, it has recently been argued that anammox alone is responsible for fixed nitrogen loss in the OMZs. Here we measure denitrification and anammox rates and quantify the abundance of denitrifying and anammox bacteria in the OMZ regions of the Eastern Tropical South Pacific and the Arabian Sea. We find that denitrification rather than anammox dominates the N(2) loss term in the Arabian Sea, the largest and most intense OMZ in the world ocean. In seven of eight experiments in the Arabian Sea denitrification is responsible for 87-99% of the total N(2) production. The dominance of denitrification is reproducible using two independent isotope incubation methods. In contrast, anammox is dominant in the Eastern Tropical South Pacific OMZ, as detected using one of the isotope incubation methods, as previously reported. The abundance of denitrifying bacteria always exceeded that of anammox bacteria by up to 7- and 19-fold in the Eastern Tropical South Pacific and Arabian Sea, respectively. Geographic and temporal variability in carbon supply may be responsible for the different contributions of denitrification and anammox in these two OMZs. The large contribution of denitrification to N(2) loss in the Arabian Sea indicates the global significance of denitrification to the oceanic nitrogen budget.

  14. Effects of combined application of organic and inorganic fertilizers plus nitrification inhibitor DMPP on nitrogen runoff loss in vegetable soils.

    PubMed

    Yu, Qiaogang; Ma, Junwei; Zou, Ping; Lin, Hui; Sun, Wanchun; Yin, Jianzhen; Fu, Jianrong

    2015-01-01

    The application of nitrogen fertilizers leads to various ecological problems such as large amounts of nitrogen runoff loss causing water body eutrophication. The proposal that nitrification inhibitors could be used as nitrogen runoff loss retardants has been suggested in many countries. In this study, simulated artificial rainfall was used to illustrate the effect of the nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen loss from vegetable fields under combined organic and inorganic nitrogen fertilizer application. The results showed that during the three-time simulated artificial rainfall period, the ammonium nitrogen content in the surface runoff water collected from the DMPP application treatment increased by 1.05, 1.13, and 1.10 times compared to regular organic and inorganic combined fertilization treatment, respectively. In the organic and inorganic combined fertilization with DMPP addition treatment, the nitrate nitrogen content decreased by 38.8, 43.0, and 30.1% in the three simulated artificial rainfall runoff water, respectively. Besides, the nitrite nitrogen content decreased by 95.4, 96.7, and 94.1% in the three-time simulated artificial rainfall runoff water, respectively. A robust decline in the nitrate and nitrite nitrogen surface runoff loss could be observed in the treatments after the DMPP addition. The nitrite nitrogen in DMPP addition treatment exhibited a significant low level, which is near to the no fertilizer application treatment. Compared to only organic and inorganic combined fertilizer treatment, the total inorganic nitrogen runoff loss declined by 22.0 to 45.3% in the organic and inorganic combined fertilizers with DMPP addition treatment. Therefore, DMPP could be used as an effective nitrification inhibitor to control the soil ammonium oxidation in agriculture and decline the nitrogen runoff loss, minimizing the nitrogen transformation risk to the water body and being beneficial for the ecological environment.

  15. A SIMPLE MODEL OF THE EFFECTS OF NITROGEN LOADING, FRESHWATER RESIDENCE TIME, AND INTERNAL LOSSES ON THE NITROGEN CONCENTRATIONS AND EXPORT IN ESTUARIES

    EPA Science Inventory

    This simple model uses the annual loading rate of total nitrogen (TN) and the water residence time to calculate average annual TN concentration and internal loss rates (e.g. denitrification and incorporation in sediments) in an estuary, and rate of nitrogen export across the seaw...

  16. Management options to limit nitrate leaching from grassland

    NASA Astrophysics Data System (ADS)

    Cuttle, S. P.; Scholefield, D.

    1995-12-01

    Nitrate leaching can be reduced by the adoption of less intensive grassland systems which, though requiring a greater land area to achieve the same agricultural output, result in less nitrate leaching per unit of production than do intensively managed grasslands. The economic penalties associated with reductions in output can be partly offset by greater reliance on symbiotic nitrogen fixation and the use of clover-based swards in place of synthetic N fertilisers. Alternatively, specific measures can be adopted to improve the efficiency of nitrogen use in intensively managed systems in order to maintain high outputs but with reduced losses. Controls should take account of other forms of loss and flows of nitrogen between grassland and other components of the whole-farm system and, in most instances, should result in an overall reduction in nitrogen inputs. Removing stock from the fields earlier in the grazing season will reduce the accumulation of high concentrations of potentially leachable nitrate in the soil of grazed pastures but will increase the quantity of manure produced by housed animals and the need to recycle this effectively. Supplementing grass diets with low-nitrogen forages such as maize silage will reduce the quantity of nitrogen excreted by livestock but may increase the potential for nitrate leaching elsewhere on the farm if changes to cropping patterns involve more frequent cultivation of grassland. Improved utilisation by the sward of nitrogen in animal excreta and manures and released by mineralisation of soil organic matter will permit equivalent reductions to be made in fertiliser inputs, provided that adequate information is available about the supply of nitrogen from these non-fertiliser sources.

  17. Effects of dietary protein concentration on ammonia volatilization, nitrate leaching, and plant nitrogen uptake from dairy manure applied to lysimeters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This lysimeter experiment was designed to investigate the effects of dietary crude protein (CP) concentration on nitrate-N (NO3-N) and ammonia (NH3) losses from dairy manure applied to soil and manure N use for plant growth. Lactating dairy cows were fed diets with 16.7 (HighCP) or 14.8% (LowCP) cru...

  18. Responses of Nitrogen Utilization and Apparent Nitrogen Loss to Different Control Measures in the Wheat and Maize Rotation System

    PubMed Central

    Peng, Zhengping; Liu, Yanan; Li, Yingchun; Abawi, Yahya; Wang, Yanqun; Men, Mingxin; An-Vo, Duc-Anh

    2017-01-01

    Nitrogen (N) is an essential macronutrient for plant growth and excessive application rates can decrease crop yield and increase N loss into the environment. Field experiments were carried out to understand the effects of N fertilizers on N utilization, crop yield and net income in wheat and maize rotation system of the North China Plain (NCP). Compared to farmers’ N rate (FN), the yield of wheat and maize in reduction N rate by 21–24% based on FN (RN) was improved by 451 kg ha-1, N uptakes improved by 17 kg ha-1 and net income increased by 1671 CNY ha-1, while apparent N loss was reduced by 156 kg ha-1. The controlled-release fertilizer with a 20% reduction of RN (CRF80%), a 20% reduction of RN together with dicyandiamide (RN80%+DCD) and a 20% reduction of RN added with nano-carbon (RN80%+NC) all resulted in an improvement in crop yield and decreased the apparent N losses compared to RN. Contrasted with RN80%+NC, the total crop yield in RN80%+DCD improved by 1185 kg ha-1, N uptake enhanced by 9 kg ha-1 and net income increased by 3929 CNY ha-1, while apparent N loss was similar. Therefore, a 37–39% overall decrease in N rate compared to farmers plus the nitrification inhibitor, DCD, was effective N control measure that increased crop yields, enhanced N efficiencies, and improved economic benefits, while mitigating apparent N loss. There is considerable scope for improved N use effieincy in the intensive wheat -maize rotation of the NCP. PMID:28228772

  19. Responses of Nitrogen Utilization and Apparent Nitrogen Loss to Different Control Measures in the Wheat and Maize Rotation System.

    PubMed

    Peng, Zhengping; Liu, Yanan; Li, Yingchun; Abawi, Yahya; Wang, Yanqun; Men, Mingxin; An-Vo, Duc-Anh

    2017-01-01

    Nitrogen (N) is an essential macronutrient for plant growth and excessive application rates can decrease crop yield and increase N loss into the environment. Field experiments were carried out to understand the effects of N fertilizers on N utilization, crop yield and net income in wheat and maize rotation system of the North China Plain (NCP). Compared to farmers' N rate (FN), the yield of wheat and maize in reduction N rate by 21-24% based on FN (RN) was improved by 451 kg ha(-1), N uptakes improved by 17 kg ha(-1) and net income increased by 1671 CNY ha(-1), while apparent N loss was reduced by 156 kg ha(-1). The controlled-release fertilizer with a 20% reduction of RN (CRF80%), a 20% reduction of RN together with dicyandiamide (RN80%+DCD) and a 20% reduction of RN added with nano-carbon (RN80%+NC) all resulted in an improvement in crop yield and decreased the apparent N losses compared to RN. Contrasted with RN80%+NC, the total crop yield in RN80%+DCD improved by 1185 kg ha(-1), N uptake enhanced by 9 kg ha(-1) and net income increased by 3929 CNY ha(-1), while apparent N loss was similar. Therefore, a 37-39% overall decrease in N rate compared to farmers plus the nitrification inhibitor, DCD, was effective N control measure that increased crop yields, enhanced N efficiencies, and improved economic benefits, while mitigating apparent N loss. There is considerable scope for improved N use effieincy in the intensive wheat -maize rotation of the NCP.

  20. Role of soil erodibility in affecting available nitrogen and phosphorus losses under simulated rainfall

    NASA Astrophysics Data System (ADS)

    Wang, Guoqiang; Wu, Binbin; Zhang, Lei; Jiang, Hong; Xu, Zongxue

    2014-06-01

    The loss of available nutrients and the effects of soil erodibility on available nutrients losses were rarely researched. Here, laboratory simulation experiments were conducted to determine the soil erodibility effects on the available nitrogen (AN) and phosphorus (AP) losses. The impacts of rainfall intensity and slope on AN and AP losses were also studied. Two contrasting agricultural soils (Burozems and Cinnamon) that occur throughout the northern erosion region of China were selected. Two rainfall intensities (60 and 120 mm h-1) and two slopes (10% and 20%) were studied. Overall, greater runoff, sediment and available nutrient losses occurred from the Cinnamon soil due to its greater soil erodibility, which was approximately 2.8 times greater than that of the Burozems soil. The influence of runoff on sediment was positively linear. The absolute slope of the regression line between runoff rate and sediment yield rate was suitable as a soil erodibility indicator. Runoff-associated AN and AP losses were mainly controlled by runoff rate, and were weakly affected by soil erodibility (p > 0.05). However, soil erodibility significantly influenced the sediment-associated AN and AP losses (p < 0.01), and a positive logarithmic correlation best described their relationships. Since the runoff-associated AN and AP losses dominated the total AN and AP losses for both soils, soil erodibility also exhibited negligible influence on the total AN and AP losses (p > 0.05). Increasing rainfall intensity and slope generally increased the runoff, sediment, and available nutrient losses for both soils, but had no significant influences on their relationships. Our results provide a better understanding of soil and nutrient loss mechanisms.

  1. Realistic diversity loss and variation in soil depth independently affect community-level plant nitrogen use.

    PubMed

    Selmants, Paul C; Zavaleta, Erika S; Wolf, Amelia A

    2014-01-01

    Numerous experiments have demonstrated that diverse plant communities use nitrogen (N) more completely and efficiently, with implications for how species conservation efforts might influence N cycling and retention in terrestrial ecosystems. However, most such experiments have randomly manipulated species richness and minimized environmental heterogeneity, two design aspects that may reduce applicability to real ecosystems. Here we present results from an experiment directly comparing how realistic and randomized plant species losses affect plant N use across a gradient of soil depth in a native-dominated serpentine grassland in California. We found that the strength of the species richness effect on plant N use did not increase with soil depth in either the realistic or randomized species loss scenarios, indicating that the increased vertical heterogeneity conferred by deeper soils did not lead to greater complementarity among species in this ecosystem. Realistic species losses significantly reduced plant N uptake and altered N-use efficiency, while randomized species losses had no effect on plant N use. Increasing soil depth positively affected plant N uptake in both loss order scenarios but had a weaker effect on plant N use than did realistic species losses. Our results illustrate that realistic species losses can have functional consequences that differ distinctly from randomized losses, and that species diversity effects can be independent of and outweigh those of environmental heterogeneity on ecosystem functioning. Our findings also support the value of conservation efforts aimed at maintaining biodiversity to help buffer ecosystems against increasing anthropogenic N loading.

  2. Tile drain losses of nitrogen and phosphorus from fields under integrated and organic crop rotations. A four-year study on a clay soil in southwest Sweden.

    PubMed

    Stenberg, Maria; Ulén, Barbro; Söderström, Mats; Roland, Björn; Delin, Karl; Helander, Carl-Anders

    2012-09-15

    In order to explore the influence of site-specific soil properties on nitrogen (N) and phosphorus (P) losses between individual fields and crop sequences, 16 drained fields with clay soils were investigated in a four-year study. Mean total N (TN) loss was 6.6-11.1 from a conventional, 14.3-21.5 from an organic and 13.1-23.9 kg ha(-1) year(-1) from an integrated cropping system across a 4 year period, with 75% in nitrate form (NO(3)-N). Mean total P (TP) loss was 0.96-3.03, 0.99-4.63 and 0.76-2.67 kg ha(-1) year(-1), from the three systems respectively during the same period, with 25% in dissolved reactive form (DRP). Median N efficiency was calculated to be 70% including gains from estimated N fixation. According to principal component factor (PCA) analysis, field characteristics and cropping system were generally more important for losses of N and P than year. Accumulation of soil mineral N in the autumn and (estimated) N fixation was important for N leaching. No P fertilisers were used at the site in either cropping system. Total P concentration in drainage water from each of the fields was marginally significantly (p<0.05) correlated to TP concentration in the topsoil (r=0.52), measured in hydrochloric acid extract (P-HCl). Mean DRP concentrations were significantly (p<0.01) correlated to degree of P saturation (DPS-AL) and soil carbon (C) content in the topsoil (r=0.63). Good establishment of a crop with efficient nutrient uptake and good soil structure was general preconditions for low nutrient leaching. Incorporation of ley by tillage operations in the summer before autumn crop establishment and repeated operations in autumn as well, increased N leaching. Crop management in sequences with leguminous crops needs to be considered carefully when designing cropping systems high efficiency in N utilisation and low environmental impact.

  3. Deposition and leaching of sulfur, nitrogen and calcium in four forested catchments in China: implications for acidification.

    PubMed

    Larssen, Thorjørn; Duan, Lei; Mulder, Jan

    2011-02-15

    Here we present the first detailed study on fluxes of sulfur (S), nitrogen (N), and major cations in Chinese subtropical forest catchments. Data are from four study sites, differing in inputs of atmospheric pollutants and sensitivity to acidification. Results show important differences from most sites in North America and Europe. Dry deposition of S, N, and calcium (Ca) is considerably larger than wet deposition in most cases causing deposition fluxes ranging from moderate to very high, both for acidifying compounds (S deposition 1.5-10.5 kiloequivalents per hectare and year (keq ha(-1) yr(-1)); N deposition 0.4 to 2.5 keq ha(-1) yr(-1)) and for alkaline compounds (Ca deposition 0.8 to 5.7 keq ha(-1) yr(-1)). More than half of the input of acidity is neutralized by alkalinity associated with Ca deposition. Furthermore, the retention of incoming S and N is small in the soil root zone, but considerable in the deeper soils or riparian zone. Drainage water from the root zone of the soils at the two sites with the highest deposition show pronounced acidification. For the two sites with moderate deposition inputs, the root zones are retaining some of the incoming S and buffer some of the incoming acidity. The subsoils and the riparian zonesare strong sinks for N, S, and Ca. This is associated with substantial acid neutralization at all sites. These features are of major importance for the understanding of the long-term effects of acidification in China.

  4. Environmental Nitrogen Losses from Commercial Crop Production Systems in the Suwannee River Basin of Florida.

    PubMed

    Prasad, Rishi; Hochmuth, George J

    2016-01-01

    The springs and the Suwannee river of northern Florida in Middle Suwanee River Basin (MSRB) are among several examples in this planet that have shown a temporal trend of increasing nitrate concentration primarily due to the impacts of non-point sources such as agriculture. The rate of nitrate increase in the river as documented by Ham and Hatzell (1996) was 0.02 mg N L-1 y-1. Best management practices (BMPs) for nutrients were adopted by the commercial farms in the MSRB region to reduce the amounts of pollutants entering the water bodies, however the effectiveness of BMPs remains a topic of interest and discussion among the researchers, environmental administrators and policy makers about the loads of nitrogen entering into groundwater and river systems. Through this study, an initiative was taken to estimate nitrogen losses into the environment from commercial production systems of row and vegetable crops that had adopted BMPs and were under a presumption of compliance with state water quality standards. Nitrogen mass budget was constructed by quantifying the N sources and sinks for three crops (potato (Solanum tuberosum L.), sweet corn (Zea mays L.) and silage corn (Zea mays L.)) over a four year period (2010-2013) on a large representative commercial farm in northern Florida. Fertilizer N was found to be the primary N input and represented 98.0 ± 1.4, 91.0 ± 13.9, 78.0 ± 17.3% of the total N input for potato, sweet corn, and silage corn, respectively. Average crop N uptake represented 55.5%, 60.5%, and 65.2% of the mean total input N whereas average mineral N left in top 0.3 m soil layer at harvest represented 9.1%, 4.5%, and 2.6% of the mean total input N. Mean environmental N losses represented 35.3%, 34.3%, and 32.7% of the mean total input N for potato, sweet corn, and silage corn, respectively. Nitrogen losses showed a linear trend with increase in N inputs. Although, there is no quick fix for controlling N losses from crop production in MSRB, the

  5. Environmental Nitrogen Losses from Commercial Crop Production Systems in the Suwannee River Basin of Florida

    PubMed Central

    Prasad, Rishi; Hochmuth, George J.

    2016-01-01

    The springs and the Suwannee river of northern Florida in Middle Suwanee River Basin (MSRB) are among several examples in this planet that have shown a temporal trend of increasing nitrate concentration primarily due to the impacts of non-point sources such as agriculture. The rate of nitrate increase in the river as documented by Ham and Hatzell (1996) was 0.02 mg N L-1 y-1. Best management practices (BMPs) for nutrients were adopted by the commercial farms in the MSRB region to reduce the amounts of pollutants entering the water bodies, however the effectiveness of BMPs remains a topic of interest and discussion among the researchers, environmental administrators and policy makers about the loads of nitrogen entering into groundwater and river systems. Through this study, an initiative was taken to estimate nitrogen losses into the environment from commercial production systems of row and vegetable crops that had adopted BMPs and were under a presumption of compliance with state water quality standards. Nitrogen mass budget was constructed by quantifying the N sources and sinks for three crops (potato (Solanum tuberosum L.), sweet corn (Zea mays L.) and silage corn (Zea mays L.)) over a four year period (2010–2013) on a large representative commercial farm in northern Florida. Fertilizer N was found to be the primary N input and represented 98.0 ± 1.4, 91.0 ± 13.9, 78.0 ± 17.3% of the total N input for potato, sweet corn, and silage corn, respectively. Average crop N uptake represented 55.5%, 60.5%, and 65.2% of the mean total input N whereas average mineral N left in top 0.3 m soil layer at harvest represented 9.1%, 4.5%, and 2.6% of the mean total input N. Mean environmental N losses represented 35.3%, 34.3%, and 32.7% of the mean total input N for potato, sweet corn, and silage corn, respectively. Nitrogen losses showed a linear trend with increase in N inputs. Although, there is no quick fix for controlling N losses from crop production in MSRB, the

  6. Ecosystem responses to warming-induced plant species loss and increased nitrogen availability in a Rocky Mountain subalpine meadow

    NASA Astrophysics Data System (ADS)

    Smith, Molly Elizabeth

    Climate change is predicted to be an important driver of future biodiversity changes, especially in mountainous environments. Climate warming-induced plant species loss is likely to be non-random and based on species-specific susceptibility to rising temperatures. Experimental warming results from a subalpine meadow in Colorado suggest that warming adversely affects shallow-rooted forb species in this ecosystem. To examine the ecological consequences of losing this warming-sensitive species group, I experimentally removed all shallow-rooted forb species from otherwise intact subalpine meadow plots. Since experimental warming also resulted in increased soil nitrogen availability, I crossed the removal treatment with a nitrogen addition treatment to determine whether the loss of shallow-rooted forbs altered the community's response to a perturbation in nitrogen availability. After three years of experimental species removal, tap-rooted forbs and grasses were able to fully compensate for the loss of shallow-rooted forbs with increased biomass production. Moreover, the remaining plant community yielded a larger biomass response to nitrogen addition when shallow-rooted forbs were removed, possibly because removal led to increased soil moisture. The loss of shallow-rooted forbs and addition of nitrogen did not have strong effects on nitrogen cycling beyond increases in the amount of nitrate moving down through the soil profile. Uptake of nitrogen into plant tissue was also not affected by either the shallow-rooted forb removal or nitrogen addition treatments, suggesting that nitrogen may not have been the most limiting resource during the experiment. I found that spatial heterogeneity generally had a greater influence on soil microbial community composition than any of the experimental treatments. I conclude that the warming-induced loss of shallow-rooted forbs did not affect biomass production, nitrogen cycling, or soil microbial community composition, but did increase

  7. Strategies for farmers and policy makers to control nitrogen losses whilst maintaining crop production.

    PubMed

    Goulding, Keith W T

    2005-09-01

    The nitrogen (N) cycle is essentially 'leaky'. The losses of small amounts of nitrate to waters and of ammonia and nitrous oxide to the atmosphere are a part of the global biogeochemical N cycle. However, intensive agricultural production, industry and vehicle use have more than doubled the amount of 'reactive' N in the environment, resulting in eutrophication, ecosystem change and health concerns. Research has identified agricultural practices that cause large losses of N and, in some cases, developed solutions. This paper discusses the problems of maintaining productivity while reducing N losses, compares conventional with low input (integrated) and organic farming systems, and discusses wider options. It also looks at the need to integrate studies on N with other environmental impacts, set in the context of the whole farm system, to provide truly sustainable agricultural systems.

  8. Strategies for farmers and policy makers to control nitrogen losses whilst maintaining crop production.

    PubMed

    Goulding, Keith W T

    2005-12-01

    The nitrogen (N) cycle is essentially 'leaky'. The losses of small amounts of nitrate to waters and of ammonia and nitrous oxide to the atmosphere are a part of the global biogeochemical N cycle. However, intensive agricultural production, industry and vehicle use have more than doubled the amount of 'reactive' N in the environment, resulting in eutrophication, ecosystem change and health concerns. Research has identified agricultural practices that cause large losses of N and, in some cases, developed solutions. This paper discusses the problems of maintaining productivity while reducing N losses, compares conventional with low input (integrated) and organic farming systems, and discusses wider options. It also looks at the need to integrate studies on N with other environmental impacts, set in the context of the whole farm system, to provide truly sustainable agricultural systems.

  9. Riparian zones attenuate nitrogen loss following bark beetle-induced lodgepole pine mortality

    NASA Astrophysics Data System (ADS)

    Biederman, Joel A.; Meixner, Thomas; Harpold, Adrian A.; Reed, David E.; Gutmann, Ethan D.; Gaun, Janelle A.; Brooks, Paul D.

    2016-03-01

    A North American bark beetle infestation has killed billions of trees, increasing soil nitrogen and raising concern for N loss impacts on downstream ecosystems and water resources. There is surprisingly little evidence of stream N response in large basins, which may result from surviving vegetation uptake, gaseous loss, or dilution by streamflow from unimpacted stands. Observations are lacking along hydrologic flow paths connecting soils with streams, challenging our ability to determine where and how attenuation occurs. Here we quantified biogeochemical concentrations and fluxes at a lodgepole pine-dominated site where bark beetle infestation killed 50-60% of trees. We used nested observations along hydrologic flow paths connecting hillslope soils to streams of up to third order. We found soil water NO3 concentrations increased 100-fold compared to prior research at this and nearby southeast Wyoming sites. Nitrogen was lost below the major rooting zone to hillslope groundwater, where dissolved organic nitrogen (DON) increased by 3-10 times (mean 1.65 mg L-1) and NO3-N increased more than 100-fold (3.68 mg L-1) compared to preinfestation concentrations. Most of this N was removed as hillslope groundwater drained through riparian soils, and NO3 remained low in streams. DON entering the stream decreased 50% within 5 km downstream, to concentrations typical of unimpacted subalpine streams (~0.3 mg L-1). Although beetle outbreak caused hillslope N losses similar to other disturbances, up to 5.5 kg ha-1y-1, riparian and in-stream removal limited headwater catchment export to <1 kg ha-1y-1. These observations suggest riparian removal was the dominant mechanism preventing hillslope N loss from impacting streams.

  10. Nitrogen Losses in Runoff from Row-cropped Watersheds: Environmental Benefits of Native Prairie Filter Strips

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Helmers, M. J.; Asbjornsen, H.; Kolka, R. K.; Tomer, M. D.

    2011-12-01

    Loss of nitrogen in runoff from agricultural landscapes is a serious problem in the Midwestern United States due to inappropriate/intensive management practices. Among other best management practices, vegetative filter strips have been effectively adopted to reduce pollutant transport with agricultural runoff. In this study, twelve ephemeral watersheds at the Neal Smith National Wildlife Refuge in Central Iowa were used to evaluate the effectiveness of native prairie filter strips (NPFS) in reducing total nitrogen (TN) and nitrate-N (NO3-N) loss from row-cropped watersheds. Small amounts of NPFS were incorporated at different locations within the watersheds in fall 2006 using a balanced incomplete block design. A no-till 2-yr corn-soybean rotation was adopted in nonperennial areas since spring 2007. Each watershed was instrumented with an H-flume, a flow-monitoring device, and an ISCO water sampler in 2007. Runoff samples during the growing season between 2007 and 2010 were analyzed for TN and NO3-N concentrations for each individual rainfall event. The 4-year mean annual TN loss for watersheds with NPFS was 6.9 kg ha-1, approximately 85% lower than TN loss from 100% row-cropped watersheds (47.7 kg ha-1). Mean annual NO3-N loss during the growing season was 4.2 and 1.3 kg ha-1 for the watersheds with and without NPFS, respectively. The results of this study suggest that incorporation of small amounts of NPFS within annual rowcrop systems could greatly reduce TN and NO3-N loss from agricultural watersheds.

  11. Simulation of Long-Term Carbon and Nitrogen Dynamics in Grassland-Based Dairy Farming Systems to Evaluate Mitigation Strategies for Nutrient Losses.

    PubMed

    Shah, Ghulam Abbas; Groot, Jeroen C J; Shah, Ghulam Mustafa; Lantinga, Egbert A

    2013-01-01

    Many measures have been proposed to mitigate gaseous emissions and other nutrient losses from agroecosystems, which can have large detrimental effects for the quality of soils, water and air, and contribute to eutrophication and global warming. Due to complexities in farm management, biological interactions and emission measurements, most experiments focus on analysis of short-term effects of isolated mitigation practices. Here we present a model that allows simulating long-term effects at the whole-farm level of combined measures related to grassland management, animal housing and manure handling after excretion, during storage and after field application. The model describes the dynamics of pools of organic carbon and nitrogen (N), and of inorganic N, as affected by farm management in grassland-based dairy systems. We assessed the long-term effects of delayed grass mowing, housing type (cubicle and sloping floor barns, resulting in production of slurry and solid cattle manure, respectively), manure additives, contrasting manure storage methods and irrigation after application of covered manure. Simulations demonstrated that individually applied practices often result in compensatory loss pathways. For instance, methods to reduce ammonia emissions during storage like roofing or covering of manure led to larger losses through ammonia volatilization, nitrate leaching or denitrification after application, unless extra measures like irrigation were used. A strategy of combined management practices of delayed mowing and fertilization with solid cattle manure that is treated with zeolite, stored under an impermeable sheet and irrigated after application was effective to increase soil carbon stocks, increase feed self-sufficiency and reduce losses by ammonia volatilization and soil N losses. Although long-term datasets (>25 years) of farm nutrient dynamics and loss flows are not available to validate the model, the model is firmly based on knowledge of processes and

  12. Simulation of Long-Term Carbon and Nitrogen Dynamics in Grassland-Based Dairy Farming Systems to Evaluate Mitigation Strategies for Nutrient Losses

    PubMed Central

    Shah, Ghulam Abbas; Groot, Jeroen C.J.; Shah, Ghulam Mustafa; Lantinga, Egbert A.

    2013-01-01

    Many measures have been proposed to mitigate gaseous emissions and other nutrient losses from agroecosystems, which can have large detrimental effects for the quality of soils, water and air, and contribute to eutrophication and global warming. Due to complexities in farm management, biological interactions and emission measurements, most experiments focus on analysis of short-term effects of isolated mitigation practices. Here we present a model that allows simulating long-term effects at the whole-farm level of combined measures related to grassland management, animal housing and manure handling after excretion, during storage and after field application. The model describes the dynamics of pools of organic carbon and nitrogen (N), and of inorganic N, as affected by farm management in grassland-based dairy systems. We assessed the long-term effects of delayed grass mowing, housing type (cubicle and sloping floor barns, resulting in production of slurry and solid cattle manure, respectively), manure additives, contrasting manure storage methods and irrigation after application of covered manure. Simulations demonstrated that individually applied practices often result in compensatory loss pathways. For instance, methods to reduce ammonia emissions during storage like roofing or covering of manure led to larger losses through ammonia volatilization, nitrate leaching or denitrification after application, unless extra measures like irrigation were used. A strategy of combined management practices of delayed mowing and fertilization with solid cattle manure that is treated with zeolite, stored under an impermeable sheet and irrigated after application was effective to increase soil carbon stocks, increase feed self-sufficiency and reduce losses by ammonia volatilization and soil N losses. Although long-term datasets (>25 years) of farm nutrient dynamics and loss flows are not available to validate the model, the model is firmly based on knowledge of processes and

  13. Implications of Land-Use and Land-Management Changes for Nitrogen Losses in South American Ecosystems

    NASA Astrophysics Data System (ADS)

    Zarakas, C.

    2015-12-01

    South America has experienced extensive land-use and land-management changes, which accelerated in the 19th century and are projected to continue in the future. As a result, increased anthropogenic nitrogen (N) inputs via cultivation of nitrogen-fixing crops and application of fertilizer and manure have altered the terrestrial-aquatic N cycle. Anthropogenic perturbations to the N cycle propagate through the ecosystem, impacting downstream freshwater and coastal life, terrestrial and riverine N2O emissions, and carbon cycling throughout the system. We used the Geophysical Fluid Dynamics Laboratory LM3-TAN (Terrestrial-Aquatic Nitrogen) model to simulate anthropogenic influences on nitrogen losses across terrestrial and riverine systems in South America from 1700 to 2050. The model's representation of ecological, hydrological, and biogeochemical processes captures the transport and transformation of nitrogen throughout the vegetation-soil-river continuum, enabling a more comprehensive accounting of nitrogen losses than previous estimates. We find that land-use and land-management changes increase nitrogen losses and explore the difference in regional patterns between the Amazon and La Plata basins. We highlight the importance of biological fixation and demonstrate that historical changes in nitrogen losses have been more driven by the type of crop introduced than by the amount of fertilizer used.

  14. Reducing nitrogen loss and salinity during 'struvite' food waste composting by zeolite amendment.

    PubMed

    Chan, Man Ting; Selvam, Ammaiyappan; Wong, Jonathan W C

    2016-01-01

    Struvite formation during composting through supplementation of Mg and P salts conserved nitrogen but in the same time increased the electrical conductivity (EC) of the compost limiting its application. Therefore the present study aimed at utilizing zeolite to control the EC under 'struvite' composting of food waste. Zeolite at 5% and 10% (dry weight basis) was supplemented to the composting mass receiving Mg and P salts and compared with treatment with Mg and P salts only and the control without any amendment. Addition of Mg and P salts effectively buffered the pH to ∼8.0 but also increased the EC of the compost to 6.45mS/cm. Co-amendment with 10% zeolite effectively reduced the EC down to 2.82mS/cm and improved compost maturity. It also increased the adsorption of ammonium ions reducing ammonia loss to 18% resulting in higher total nitrogen content in the final compost.

  15. Environmental and plant community determinants of species loss following nitrogen enrichment

    USGS Publications Warehouse

    Clark, C.M.; Cleland, E.E.; Collins, S.L.; Fargione, J.E.; Gough, L.; Gross, K.L.; Pennings, S.C.; Suding, K.N.; Grace, J.B.

    2007-01-01

    Global energy use and food production have increased nitrogen inputs to ecosystems worldwide, impacting plant community diversity, composition, and function. Previous studies show considerable variation across terrestrial herbaceous ecosystems in the magnitude of species loss following nitrogen (N) enrichment. What controls this variation remains unknown. We present results from 23 N-addition experiments across North America, representing a range of climatic, soil and plant community properties, to determine conditions that lead to greater diversity decline. Species loss in these communities ranged from 0 to 65% of control richness. Using hierarchical structural equation modelling, we found greater species loss in communities with a lower soil cation exchange capacity, colder regional temperature, and larger production increase following N addition, independent of initial species richness, plant productivity, and the relative abundance of most plant functional groups. Our results indicate sensitivity to N addition is co-determined by environmental conditions and production responsiveness, which overwhelm the effects of initial community structure and composition. ?? 2007 Blackwell Publishing Ltd/CNRS.

  16. Nutritional and management methods to decrease nitrogen losses from beef feedlots.

    PubMed

    Erickson, G; Klopfenstein, T

    2010-04-01

    Nitrogen losses from open beef feedlots are a concern. Methods that decrease volatilization losses will lead to greater manure N, which is likely to be beneficial in open lot beef operations. Twelve or more pens were dedicated to N research whereby N intake, retention, and excretion were quantified and a mass balance conducted using manure, runoff, soil balance, and loss quantities. The objective was to decrease N volatilization losses or increase manure N or both. Dietary CP affects N excretion and N volatilization losses. Four experiments across 2 yr compared industry average CP (13%) to diets that were phase-fed to not exceed protein requirements (12.1 to 10.9%). Phase-fed cattle excreted 12 to 21% less N (P < 0.01), and N volatilization losses were reduced 15 to 33% (P < 0.01). In 2 other experiments, phase-fed diets were formulated to recycle undegradable intake protein. Steer G:F was similar (P = 0.18) or improved (P = 0.09), whereas N excretion and N volatilization losses tended to be reduced (P < 0.11) and N in manure was not affected (P > 0.35) compared with cattle fed 13% CP. Feeding less protein did not affect manure N, indicating manure N from open lots is related to other factors. A series of experiments evaluated increasing OM on the pen surface to increase N in manure. Feeding less digestible diets using fiber increased manure N (P < 0.01) and decreased (P < 0.10) N volatilization losses in 2 experiments conducted from November to May, but did not affect (P > 0.30) manure N or volatilization losses during 2 summer experiments. Adding bedding (i.e., OM) increased manure N in the winter as well. Another method evaluated was increasing pen cleaning frequency, which decreased N volatilization losses by 19 to 44% and increased manure N by 26 to 41% across 3 experiments. Other methods, such as acidifying manure by manipulating dietary cation anion difference, clinoptilite zeolite clay addition, and feeding different amounts of by-products had variable

  17. Nitrogen concentrations and losses from agricultural streams in the Nordic and Baltic countries

    NASA Astrophysics Data System (ADS)

    Stålnacke, Per; Bechmann, Marianne; Blicher-Mathiesen, Gitte; Iital, Arvo; Kyllmar, Katarina; Koskiaho, Jari; Lagzdins, Ainis; Povilaitis, Arvydas

    2015-04-01

    Assessment of long-term trends is one of the key objectives in most national water quality monitoring programmes. It is for example essential that we know how long it can take to detect the response in agricultural streams to changes in agriculture and implemented measures, because such information is needed to allow environmental authorities and decision and policy makers to establish realistic goals. Thus, long-term monitoring data is the key to cover future management needs and demands such as implementation of various EU-Directives (e.g., WFD, the Nitrates Directive). This paper in a uniform fashion examines the levels and temporal trends of nitrogen concentrations and losses in streams draining agricultural catchment areas in the Nordic and Baltic countries. 35 catchments (range 0.1-33km2) in Norway (9), Denmark (5), Sweden (8), Finland (4), Estonia (3), Latvia (3) and Lithuania (3) were selected for the study. Most of these catchments are part of national water quality monitoring programmes and initially selected to represent the major crops, soil types and climatic conditions in each country. The longest time series where 23 years (1988-2010) while the shortest one was 10 years (2002-2011). The reasons for these identified trends and no-trends will be discussed during the oral presentation in relation to land use, agricultural management and implementation of mitigation measures. Furthermore, the difference in mean level concentrations and losses will be discussed in relation to differences in climate, land use and agricultural management Overall the results show that agricultural catchments in the Nordic and Baltic countries exhibit different levels of nitrogen concentrations and losses, with a large interannual variability in all catchments. For example, the overall range in annual long-term mean TN losses was 6-102 kg N ha-1. Nearly one third of the investigated agricultural catchments showed statistically significant downward trends in nitrogen losses or

  18. Impact of struvite crystallization on nitrogen losses during composting of pig manure and cornstalk.

    PubMed

    Ren, Limei; Schuchardt, Frank; Shen, Yujun; Li, Guoxue; Li, Chunping

    2010-05-01

    An absorbent mixture of magnesium hydroxide (Mg(OH)(2)) and phosphoric acid (H(3)PO(4)) was added to compost mixtures of pig manure with cornstalk in different molar ratios (T1, 1:1; T2, 1:2; T3, 1:3) in order to examine its effect on controlling ammonia losses during composting. Based on the principle of struvite precipitation, and with an unamended trial as control (CK), an in-vessel composting experiment was conducted in fermenters (60L with forced aeration) in which the absorbent mixture was added with proportions of 3.8%, 7.3% and 8.9% of dry weight for T1, T2 and T3, respectively. The results showed that the total nitrogen loss was reduced from 35% to 12%, 5% and 1% of initial N mass, respectively. In the final compost, the total nitrogen content in T1, T2 and T3 was improved by 10, 14, 12gkg(-1), and NH(4)(+)-N in T1, T2 and T3 was improved by 8, 9, and 10gkg(-1), respectively, compared with the unamended trial. The results of the germination index test showed that the maturity of treatment T2 was best among the four treatments in the final compost, followed by T1, CK and T3. The results of X-ray diffraction (XRD) confirmed the formation of magnesium ammonium phosphate hexahydrate (MgNH(4)PO(4).6H(2)O:MAP) in the T1, T2 and T3 compost. Based on these results, the adsorbent mixture of Mg(OH)(2)+H(3)PO(4) could control nitrogen loss effectively during composting via struvite crystallization. However, an excess of phosphoric acid (1:3) had a negative influence on composting properties. The pH value decreased which led to reduced microorganism activity, and which finally resulted in reduced biodegradation of the organic matter.

  19. State factor relationships of dissolved organic carbon and nitrogen losses from unpolluted temperate forest watersheds

    USGS Publications Warehouse

    Perakis, S.S.; Hedin, L.O.

    2007-01-01

    We sampled 100 unpolluted, old-growth forested watersheds, divided among 13 separate study areas over 5 years in temperate southern Chile and Argentina, to evaluate relationships among dominant soil-forming state factors and dissolved carbon and nitrogen concentrations in watershed streams. These watersheds provide a unique opportunity to examine broad-scale controls over carbon (C) and nitrogen (N) biogeochemistry in the absence of significant human disturbance from chronic N deposition and land use change. Variations in the ratio dissolved organic carbon (DOC) to nitrogen (DON) in watershed streams differed by underlying soil parent material, with average C:N = 29 for watersheds underlain by volcanic ash and basalt versus C:N = 73 for sedimentary and metamorphic parent materials, consistent with stronger adsorption of low C:N hydrophobic materials by amorphous clays commonly associated with volcanic ash and basalt weathering. Mean annual precipitation was related positively to variations in both DOC (range: 0.2-9.7 mg C/L) and DON (range: 0.008-0.135 mg N/L) across study areas, suggesting that variations in water volume and concentration may act synergistically to influence C and N losses across dry to wet gradients in these forest ecosystems. Dominance of vegetation by broadleaf versus coniferous trees had negligible effects on organic C and N concentrations in comparison to abiotic factors. We conclude that precipitation volume and soil parent material are important controls over chemical losses of dissolved organic C and N from unpolluted temperate forest watersheds. Our results raise the possibility that biotic imprints on watershed C and N losses may be less pronounced in naturally N-poor forests than in areas impacted by land use change and chronic N deposition. Copyright 2007 by the American Geophysical Union.

  20. Nitrogen losses from the human small bowel: obligatory losses and the effect of physical form of food.

    PubMed Central

    Chacko, A; Cummings, J H

    1988-01-01

    The amount and form of nitrogen lost from the human small intestine and the dietary factors which influence it have been studied in six ileostomists. Over a six day period the subjects were fed a series of diets including low nitrogen (LND) 0.17 g N/day, LND + soya beans (5.87 g N/day) and a high fibre diet (HFD) (10.6 g N/day). The soya beans were fed either whole or pureed to test the effect of physical form of food. Total N, protein, amino acids, urea, and ammonia were measured in ileostomy effluent which was collected throughout the study. Total N excretion was LND 0.91 (0.04) (SE) g/day; LND + whole soya beans (WSB) 2.26 (0.15) g/day; LND + pureed soya beans (PSB) 1.42 (0.12) g/day (WSB v PSB, p less than 0.001); and HFD 2.17 (0.11) g/day (HFD v PSB, p less than 0.001, HFD v WSB, NS). N losses as urea, ammonia, and free amino acids were less than 10-15% of total N, the remainder being protein (48-51%) and (by difference) peptides (20-30%). Eighty to 85% of effluent N was in the insoluble (pellet) fraction except on the low N diet where it was 66%. The physical form of food clearly influenced N digestibility in the soya beans whilst changes in dietary fibre seem not to have a significant effect. PMID:2838402

  1. Major sources of nitrogen input and loss in the upper Snake River basin, Idaho and western Wyoming, 1990

    USGS Publications Warehouse

    Rupert, Michael

    1996-01-01

    A mass balance of total nitrogen input and loss in Gooding, Jerome, Lincoln, and Twin Falls Counties suggests that more than 6,000,000 kg (6,600 tons) of total nitrogen is input in this four-county area than is discharged by the Snake River. This excess nitrogen probably is utilized by aquatic vegetation in the Snake River (causing eutrophication), stored as nitrogen in soil, stored as nitrate in the ground water and eventually discharged through the springs, utilized by noncrop vegetation, and lost through denitrification.

  2. Extensive nitrogen loss from permeable sediments off North-West Africa

    NASA Astrophysics Data System (ADS)

    Sokoll, Sarah; Lavik, Gaute; Sommer, Stefan; Goldhammer, Tobias; Kuypers, Marcel M. M.; Holtappels, Moritz

    2016-04-01

    The upwelling area off North-West Africa is characterized by high export production, high nitrate and low oxygen concentration in bottom waters. The underlying sediment consists of sands that cover most of the continental shelf. Due to their permeability sands allow for fast advective pore water transport and can exhibit high rates of nitrogen (N) loss via denitrification as reported for anthropogenically eutrophied regions. However, N loss from sands underlying naturally eutrophied waters is not well studied, and in particular, N loss from the North-West African shelf is poorly constrained. During two research cruises in April/May 2010/2011, sediment was sampled along the North-West African shelf and volumetric denitrification rates were measured in sediment layers down to 8 cm depth using slurry incubations with 15N-labeled nitrate. Areal N loss was calculated by integrating volumetric rates down to the nitrate penetration depth derived from pore water profiles. Areal N loss was neither correlated with water depth nor with bottom water concentrations of nitrate and oxygen but was strongly dependent on sediment grain size and permeability. The derived empirical relation between benthic N loss and grains size suggests that pore water advection is an important regulating parameter for benthic denitrification in sands and further allowed extrapolating rates to an area of 53,000 km2 using detailed sediment maps. Denitrification from this region amounts to 995 kt yr-1 (average 3.6 mmol m-2 d-1) which is 4 times higher than previous estimates based on diffusive pore water transport. Sandy sediments cover 50-60% of the continental shelf and thus may contribute significantly to the global benthic N loss.

  3. The strength of the biotic compartment in retaining nitrogen additions prevents nitrogen losses from a Mediterranean maquis

    NASA Astrophysics Data System (ADS)

    Dias, T.; Martins-Loução, M. A.; Sheppard, L.; Cruz, C.

    2012-01-01

    Nitrogen (N) is one of the nutrients most limiting to ecosystem productivity. However, N availability is increasing globally, which may affect ecosystem functions and stability. To understand the role of each ecosystem compartment in the cycling of increased N, we studied the initial response of a nutrient-poor ecosystem, a Mediterranean maquis, to increased N deposition. N availability (dose and form) was modified by three N additions over the year (middle autumn/winter, spring and summer). Soil inorganic N pools (nitrate in particular) strongly reflected the N additions in autumn, almost matching the total N added over the three additions. Cistus ladanifer, the dominant plant species, responded to the increased N (cover and N concentration in leaves and litter). Given that leaf shedding occurs in the summer, the importance of this N pool returning to the soil through litter decomposition on the total soil inorganic N in autumn was investigated. Data suggest that living plants and litter have a crucial role in preventing N losses from Mediterranean maquis. This is the first integrated field study on how European Mediterranean ecosystems retain increased N of different forms and doses, however longer-term studies are needed to explore the generality of this study's observations.

  4. The strength of the biotic compartment to retain nitrogen additions prevents nitrogen losses from a Mediterranean maquis

    NASA Astrophysics Data System (ADS)

    Dias, T.; Martins-Loução, M. A.; Sheppard, L.; Cruz, C.

    2011-08-01

    Nitrogen (N) is one of the nutrients most limiting to ecosystem productivity. However, N availability is increasing globally, which may affect ecosystem functions and stability. To understand the role of each ecosystem compartment in the cycling of increased N, we studied the initial response of a nutrient-poor ecosystem, a Mediterranean maquis, to increased N. N availability (dose and forms) was modified by three N additions along the year (spring, summer and middle autumn/winter). Soil inorganic N pools (nitrate in particular) strongly reflected the N additions in autumn, almost matching the total N added along the three additions. Cistus ladanifer, the dominant plant species, responded to the increased N (cover and N concentration in leaves and litter), and given that leaf shedding occurs in the summer, the importance of this N pool returning to the soil through litter decomposition on the total soil inorganic N in autumn was investigated. Data suggest that living plants and litter have a crucial role in preventing N losses from Mediterranean maquis. This is the first integrated field study on how European Mediterranean ecosystems retain increased N of different forms and doses, however longer-term studies are needed to explore the generality of this study's observations.

  5. Managing tile drainage, subirrigation, and nitrogen fertilization to enhance crop yields and reduce nitrate loss.

    PubMed

    Drury, C F; Tan, C S; Reynolds, W D; Welacky, T W; Oloya, T O; Gaynor, J D

    2009-01-01

    Improving field-crop use of fertilizer nitrogen is essential for protecting water quality and increasing crop yields. The objective of this study was to determine the effectiveness of controlled tile drainage (CD) and controlled tile drainage with subsurface irrigation (CDS) for mitigating off-field nitrate losses and enhancing crop yields. The CD and CDS systems were compared on a clay loam soil to traditional unrestricted tile drainage (UTD) under a corn (Zea Mays L.)-soybean (Glycine Max. (L.) Merr.) rotation at two nitrogen (N) fertilization rates (N1: 150 kg N ha(-1) applied to corn, no N applied to soybean; N2: 200 kg N ha(-1) applied to corn, 50 kg N ha(-1) applied to soybean). The N concentrations in tile flow events with the UTD treatment exceeded the provisional long-term aquatic life limit (LT-ALL) for freshwater (4.7 mg N L(-1)) 72% of the time at the N1 rate and 78% at the N2 rate, whereas only 24% of tile flow events at N1 and 40% at N2 exceeded the LT-ALL for the CDS treatment. Exceedances in N concentration for surface runoff and tile drainage were greater during the growing season than the non-growing season. At the N1 rate, CD and CDS reduced average annual N losses via tile drainage by 44 and 66%, respectively, relative to UTD. At the N2 rate, the average annual decreases in N loss were 31 and 68%, respectively. Crop yields from CDS were increased by an average of 2.8% relative to UTD at the N2 rate but were reduced by an average of 6.5% at the N1 rate. Hence, CD and CDS were effective for reducing average nitrate losses in tile drainage, but CDS increased average crop yields only when additional N fertilizer was applied.

  6. Nitrogen losses in anoxic marine sediments driven by Thioploca-anammox bacterial consortia.

    PubMed

    Prokopenko, M G; Hirst, M B; De Brabandere, L; Lawrence, D J P; Berelson, W M; Granger, J; Chang, B X; Dawson, S; Crane, E J; Chong, L; Thamdrup, B; Townsend-Small, A; Sigman, D M

    2013-08-08

    Ninety per cent of marine organic matter burial occurs in continental margin sediments, where a substantial fraction of organic carbon escapes oxidation and enters long-term geologic storage within sedimentary rocks. In such environments, microbial metabolism is limited by the diffusive supply of electron acceptors. One strategy to optimize energy yields in a resource-limited habitat is symbiotic metabolite exchange among microbial associations. Thermodynamic and geochemical considerations indicate that microbial co-metabolisms are likely to play a critical part in sedimentary organic carbon cycling. Yet only one association, between methanotrophic archaea and sulphate-reducing bacteria, has been demonstrated in marine sediments in situ, and little is known of the role of microbial symbiotic interactions in other sedimentary biogeochemical cycles. Here we report in situ molecular and incubation-based evidence for a novel symbiotic consortium between two chemolithotrophic bacteria--anaerobic ammonium-oxidizing (anammox) bacteria and the nitrate-sequestering sulphur-oxidizing Thioploca species--in anoxic sediments of the Soledad basin at the Mexican Pacific margin. A mass balance of benthic solute fluxes and the corresponding nitrogen isotope composition of nitrate and ammonium fluxes indicate that anammox bacteria rely on Thioploca species for the supply of metabolic substrates and account for about 57 ± 21 per cent of the total benthic N2 production. We show that Thioploca-anammox symbiosis intensifies benthic fixed nitrogen losses in anoxic sediments, bypassing diffusion-imposed limitations by efficiently coupling the carbon, nitrogen and sulphur cycles.

  7. Identifying Sources and Controls of Dissolved Organic Carbon Losses in Northern Hardwood Forest Ecosystems Under Elevated Nitrogen Deposition

    NASA Astrophysics Data System (ADS)

    Smemo, K. A.; Zak, D. R.

    2004-05-01

    Anthropogenic nitrogen (N) deposition in northern hardwood forest ecosystems has modified soil carbon cycling, resulting in the substantial leaching of dissolved organic carbon (DOC). Despite the significance of this finding, the exact source of this DOC has not been found and a mechanistic explanation has been lacking. In order to identify sources of and mechanisms for this apparent N stimulation of DOC leaching, we conducted a controlled laboratory leaching experiment using soil and fresh litterfall from a previously-studied northern hardwood forest stand in northern Lower Michigan. This stand has received 10 years of both ambient and experimental (3 times ambient) atmospheric NO3- deposition. Three replicate soil and litter samples were collected from 3 plots receiving ambient and 3 plots receiving experimental NO3- deposition. Our laboratory experiment used soil and litter collected from each plot to understand if fresh leaf litter was the source of increased DOC leaching in plots receiving experimental NO3- deposition. In laboratory incubations, we investigated microbial respiration and DOC production from: 1) soil from each plot, 2) litter and soil from each plot, and 3) litter from each plot placed over sterile sand. This combination of treatments enabled us to determine the contribution of soil organic matter, fresh leaf litter, and both to DOC production. Results showed that N deposition had no significant effect on microbial respiration, but that treatment differences were significant. Most of the DOC production (75%) was associated with leaching from fresh litter. Soil was a significant sink for litter-derived DOC across the treatments, but less so in the fertilized plots where 30% more DOC was leached on average compared to un-fertilized plots. These results suggest that N deposition might not influence the production of DOC in soil and litter, but the ability of the soil to physically adsorb or the microbial population to sequester DOC inputs

  8. Changes in pig production in China and their effects on nitrogen and phosphorus use and losses.

    PubMed

    Bai, Z H; Ma, L; Qin, W; Chen, Q; Oenema, O; Zhang, F S

    2014-11-04

    China's pig production has increased manifold in the past 50 years, and this has greatly affected the nitrogen and phosphorus use and losses in the pig production sector. However, the magnitude of these changes are not well-known. Here, we provide an in-depth account of the changes in pig production--N and P use and total N and P losses in the whole pig production chain during the period 1960-2010--through simulation modeling and using data from national statistics and farm surveys. For the period of 2010-2030, we explored possible effects of technological and managerial measures aimed at improving the performances of pig production via scenario analysis. We used and further developed the NUtrient flows in Food chains, Environment and Resources use (NUFER) model to calculate the feed requirement and consumption, and N and P losses in different pig production systems for all the years. Between 1960 and 2010, pig production has largely shifted from the so-called backyard system to landless systems. The N use efficiencies at fattener level increased from 18 to 28%, due to the increased animal productivity. However, the N use efficiencies at the whole-system level decreased from 46 to 11% during this period, mainly due to the increase of landless pig farms, which rely on imported feed and have no land-base for manure disposal. The total N and P losses were 5289 and 829 Gg in 2010, which is 30 and 95 times higher than in 1960. In the business as usual scenario, the total N and P losses were projected to increase by 25 and 55% between 2010 and 2030, respectively. Analyses of other scenarios indicate that packages of technological and managerial measures can decrease total N and P losses by 64 and 95%, respectively. Such improvements require major transition in the pig production sector, notably, in manure management, herd management, and feeding practices.

  9. Nitrate-nitrogen losses through subsurface drainage under various agricultural land covers.

    PubMed

    Qi, Zhiming; Helmers, Matthew J; Christianson, Reid D; Pederson, Carl H

    2011-01-01

    Nitrate-nitrogen (NO₃-N) loading to surface water bodies from subsurface drainage is an environmental concern in the midwestern United States. The objective of this study was to investigate the effect of various land covers on NO₃-N loss through subsurface drainage. Land-cover treatments included (i) conventional corn ( L.) (C) and soybean [ (L.) Merr.] (S); (ii) winter rye ( L.) cover crop before corn (rC) and before soybean (rS); (iii) kura clover ( M. Bieb.) as a living mulch for corn (kC); and (iv) perennial forage of orchardgrass ( L.) mixed with clovers (PF). In spring, total N uptake by aboveground biomass of rye in rC, rye in rS, kura clover in kC, and grasses in PF were 14.2, 31.8, 87.0, and 46.3 kg N ha, respectively. Effect of land covers on subsurface drainage was not significant. The NO₃-N loss was significantly lower for kC and PF than C and S treatments (p < 0.05); rye cover crop did not reduce NO₃-N loss, but NO₃-N concentration was significantly reduced in rC during March to June and in rS during July to November (p < 0.05). Moreover, the increase of soil NO₃-N from early to late spring in rS was significantly lower than the S treatment (p < 0.05). This study suggests that kC and PF are effective in reducing NO₃-N loss, but these systems could lead to concerns relative to grain yield loss and change in farming practices. Management strategies for kC need further study to achieve reasonable corn yield. The effectiveness of rye cover crop on NO-N loss reduction needs further investigation under conditions of different N rates, wider weather patterns, and fall tillage.

  10. Impact of weather variability on nitrate leaching

    NASA Astrophysics Data System (ADS)

    Richards, Karl; Premrov, Alina; Hackett, Richard; Coxon, Catherine

    2016-04-01

    The loss of nitrate (NO3 - N) to water via leaching and overland flow contributes to eutrophication of freshwaters, transitional and near coastal waters with agriculture contributing significantly to nitrogen (N) loading to these water. Environmental regulations, such as the Nitrates and Water Framework Directives, have increased constraints on farmers to improve N management in regions at risk of NO3--N loss to water. In addition, farmers also have to manage their systems within a changing climate as the imapcts of climate change begin to impact resulting in more frequent extreme events such as floods and droughts. The objective of this study was to investigate the link between weather volatility and the concentration of leached NO3--N spring barley. Leaching was quantified under spring barley grown on a well-drained, gravelly sandy soil using ceramic cup samplers over 6 drainage years under the same farming practices and treatments. Soil solution NO3--N concentrations under spring barley grown by conventional inversion ploughing and reduced tillage were compared to weather parameters over the period. Weather was recorded at a national Met Eireann weather station on site. Soil solution NO3--N varied significantly between years. Within individual years NO3--N concentrations varied over the drainage season, with peak concentrations generally observed in the autumn time, decreasing thereafter. Under both treatments there was a three-fold difference in mean annual soil solution NO3--N concentration over the 6 years with no change in the agronomic practices (crop type, tillage type and fertiliser input). Soil solution nitrate concentrations were significantly influenced by weather parameters such as rainfall, effective drainage and soil moisture deficit. The impact of climate change in Ireland could lead to increased NO3--N loss to water further exacerbating eutrophication of sensitive estuaries. The increased impact on eutrophication of waters, related to climatic

  11. Impact of struvite crystallization on nitrogen losses during composting of pig manure and cornstalk

    SciTech Connect

    Ren Limei; Schuchardt, Frank; Shen Yujun; Li Guoxue; Li Chunping

    2010-05-15

    An absorbent mixture of magnesium hydroxide (Mg(OH){sub 2}) and phosphoric acid (H{sub 3}PO{sub 4}) was added to compost mixtures of pig manure with cornstalk in different molar ratios (T1, 1:1; T2, 1:2; T3, 1:3) in order to examine its effect on controlling ammonia losses during composting. Based on the principle of struvite precipitation, and with an unamended trial as control (CK), an in-vessel composting experiment was conducted in fermenters (60 L with forced aeration) in which the absorbent mixture was added with proportions of 3.8%, 7.3% and 8.9% of dry weight for T1, T2 and T3, respectively. The results showed that the total nitrogen loss was reduced from 35% to 12%, 5% and 1% of initial N mass, respectively. In the final compost, the total nitrogen content in T1, T2 and T3 was improved by 10, 14, 12 g kg{sup -1}, and NH{sub 4}{sup +}-N in T1, T2 and T3 was improved by 8, 9, and 10 g kg{sup -1}, respectively, compared with the unamended trial. The results of the germination index test showed that the maturity of treatment T2 was best among the four treatments in the final compost, followed by T1, CK and T3. The results of X-ray diffraction (XRD) confirmed the formation of magnesium ammonium phosphate hexahydrate (MgNH{sub 4}PO{sub 4}.6H{sub 2}O:MAP) in the T1, T2 and T3 compost. Based on these results, the adsorbent mixture of Mg(OH){sub 2} + H{sub 3}PO{sub 4} could control nitrogen loss effectively during composting via struvite crystallization. However, an excess of phosphoric acid (1:3) had a negative influence on composting properties. The pH value decreased which led to reduced microorganism activity, and which finally resulted in reduced biodegradation of the organic matter.

  12. Investigation of the relationship between heat loss and nitrogen excretion in elderly patients undergoing major abdominal surgery under general anaesthetic.

    PubMed

    Carli, F; Clark, M M; Woollen, J W

    1982-10-01

    An attempt was made to reduce heat loss in elderly patients undergoing major abdominal surgery. Two groups were studied. In one group, efforts were made to minimize heat loss by using a hot-water humidifier in the anaesthetic circuit, a hot-water circulating mattress under the patient and warming all i.v. fluids. Otherwise, the surgical and anaesthetic techniques were comparable. The same anaesthetic technique of nitrous oxide, oxygen, pancuronium and fentanyl with intermittent positive pressure ventilation was used in all cases. Nitrogen loss was measured in urine collected over 48 h from an indwelling urinary catheter inserted soon after induction of anaesthesia. Prevention of heat loss during anaesthesia and postoperative recovery caused a significant reduction in nitrogen loss.

  13. Global Patterns in Dissimilatory Nitrate Reduction: A Latitudinal Gradient in Nitrogen Retention and Loss

    NASA Astrophysics Data System (ADS)

    Silver, W. L.; Thompson, A. W.; Bradbury, D.; Chapin, F. S.; Ewel, J. J.; Firestone, M. K.

    2003-12-01

    Increased nitrogen (N) deposition in humid environments has the potential to significantly increase nitrous oxide (N2O) emissions via nitrification and denitrification. This potential N loss may be significantly offset by N retention from dissimilatory nitrate reduction to ammonium (DNRA). In this study, we report on rates of dissimilatory nitrate reduction to N2O and ammonium along a latitudinal gradient from the tropics to the boreal forest. We conducted laboratory experiments with forest soils from Costa Rica, Puerto Rico, California, and Alaska to determine maximum potential rates of DNRA and N2O production. We also conducted field experiments in Costa Rica, Puerto Rico, and Alaska to estimate in situ rates. Maximum potential rates of DNRA ranged from 10 ug/g/d in fertilized poplar forests in Alaska to 0.3 ug/g/d in unfertilized polyculture plantations in Costa Rica. At all sites, rates of DNRA appeared to be nitrate limited. On average, temperate and boreal forests had greater potential rates of DNRA (5 +/- 1 ug/g/d) than tropical forests (3 +/- 1 ug/g/d). Nitrogen fertilization significantly increased rates of DNRA in Alaska. Rates of maximum potential N2O flux were generally lower than DNRA rates (0.16 to 4 ug/g/d). In field experiments, rates of DNRA were greatest in tropical rain forests in Puerto Rico, followed by wet forests in Costa Rica, and black spruce forests in Alaska. Although field DNRA rates were low in Alaska, they accounted for up to 13 % of gross mineralization and 24 % of gross nitrification. At all sites, rates of N2O flux via denitrification and nitrification were significantly lower than N retention via DNRA. Our results suggest that this previously unmeasured N cycling pathway effectively competes with processes resulting in N-trace gas loss from a range of forested ecosystems.

  14. Effects of litter position on mass loss and nitrogen release in the semiarid Patagonian steppe

    NASA Astrophysics Data System (ADS)

    Austin, A. T.

    2007-05-01

    The patchy distribution of vegetation in arid and semiarid ecosystems results in a mosaic of microsites of soil properties and variable abiotic conditions, including the well-documented "islands of fertility", low nutrient conditions in exposed bare soil and large amounts of standing dead material. I evaluated the relative importance of litter position on mass loss and nutrient release in a variety of realistic litter positions both in vegetated, unvegetated, aerial and buried microsites in a natural semiarid steppe in Patagonia, Argentina. Position demonstrated a highly significant effect on mass loss for all litter types (P<0.0001), but surprisingly, the fastest decomposition occurred in litter that was suspended in aerial positions or buried (k=0.25 and 0.32 year-1, respectively), intermediate values for mass loss of litter in bare soil and in shrub removal patches (k=0.21 and 0.24 year-1, respectively), and markedly slowest decomposition occurring under shrub patches (k = 0.018 year-1). In contrast, nutrient release showed a very different pattern with nutrient immobilization occurring only in shrub and buried microsites while all other positions demonstrated a gradual decrease in nitrogen over time. These results support the idea that abiotic photodegradation may be an important driver affecting carbon losses in litter in positions exposed to solar radiation, while nutrient dynamics appear to be largely biotically mediated and concentrated in photoprotected areas where biotic activity dominates. Global change may differentially affect carbon and nutrient turnover due to the relative importance of abiotic and biotic factors affecting litter decomposition in semiarid ecosystems.

  15. The influence of woody encroachment on the nitrogen cycle: fixation, storage and gas loss

    NASA Astrophysics Data System (ADS)

    Soper, F.; Sparks, J. P.

    2015-12-01

    Woody encroachment is a pervasive land cover change throughout the tropics and subtropics. Encroachment is frequently catalyzed by nitrogen (N)-fixing trees and the resulting N inputs potentially alter whole-ecosystem N cycling, accumulation and loss. In the southern US, widespread encroachment by legume Prosopis glandulosa is associated with increased soil total N storage, inorganic N concentrations, and net mineralization and nitrification rates. To better understand the effects of this process on ecosystem N cycling, we investigated patterns of symbiotic N fixation, N accrual and soil N trace gas and N2 emissions during Prosopis encroachment into the southern Rio Grande Plains. Analyses of d15N in foliage, xylem sap and plant-available soil N suggested that N fixation rates increase with tree age and are influenced by abiotic conditions. A model of soil N accrual around individual trees, accounting for atmospheric inputs and gas losses, generates lifetimes N fixation estimates of up to 9 kg for a 100-year-old tree and current rates of 7 kg N ha-1 yr-1. However, these N inputs and increased soil cycling rates do not translate into increased N gas losses. Two years of field measurements of a complete suite of N trace gases (ammonia, nitrous oxide, nitric oxide and other oxidized N compounds) found no difference in flux between upland Prosopis groves and adjacent unencroached grasslands. Total emissions for both land cover types average 0.56-0.65 kg N ha-1 yr-1, comparable to other southern US grasslands. Additional lab experiments suggested that N2 losses are low and that field oxygen conditions are not usually conducive to denitrification. Taken together, results suggest that this ecosystem is currently experiencing a period of net N accrual under ongoing encroachment.

  16. Nitrogen

    USGS Publications Warehouse

    Apodaca, Lori E.

    2013-01-01

    The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

  17. Delayed addition of nitrogen-rich substrates during composting of municipal waste: Effects on nitrogen loss, greenhouse gas emissions and compost stability.

    PubMed

    Nigussie, Abebe; Bruun, Sander; Kuyper, Thomas W; de Neergaard, Andreas

    2017-01-01

    Municipal waste is usually composted with an N-rich substrate, such as manure, to increase the N content of the product. This means that a significant amount of nitrogen can be lost during composting. The objectives of this study were (i) to investigate the effect of split addition of a nitrogen-rich substrate (poultry manure) on nitrogen losses and greenhouse gas emissions during composting and to link this effect to different bulking agents (coffee husks and sawdust), and (ii) to assess the effect of split addition of a nitrogen-rich substrate on compost stability and sanitisation. The results showed that split addition of the nitrogen-rich substrate reduced nitrogen losses by 9% when sawdust was used and 20% when coffee husks were used as the bulking agent. Depending on the bulking agent used, split addition increased cumulative N2O emissions by 400-600% compared to single addition. In contrast, single addition increased methane emissions by up to 50% compared to split addition of the substrate. Hence, the timing of the addition of the N-rich substrate had only a marginal effect on total non-CO2 greenhouse gas emissions. Split addition of the N-rich substrate resulted in compost that was just as stable and effective at completely eradicating weed seeds as single addition. These findings therefore show that split addition of a nitrogen-rich substrate could be an option for increasing the fertilising value of municipal waste compost without having a significant effect on total greenhouse gas emissions or compost stability.

  18. Farm nitrogen balances in six European landscapes as an indicator for nitrogen losses and basis for improved management

    NASA Astrophysics Data System (ADS)

    Dalgaard, T.; Bienkowski, J. F.; Bleeker, A.; Dragosits, U.; Drouet, J. L.; Durand, P.; Frumau, A.; Hutchings, N. J.; Kedziora, A.; Magliulo, V.; Olesen, J. E.; Theobald, M. R.; Maury, O.; Akkal, N.; Cellier, P.

    2012-12-01

    Improved management of nitrogen (N) in agriculture is necessary to achieve a sustainable balance between the production of food and other biomass, and the unwanted effects of N on water pollution, greenhouse gas emissions, biodiversity deterioration and human health. To analyse farm N-losses and the complex interactions within farming systems, efficient methods for identifying emissions hotspots and evaluating mitigation measures are therefore needed. The present paper aims to fill this gap at the farm and landscape scales. Six agricultural landscapes in Poland (PL), the Netherlands (NL), France (FR), Italy (IT), Scotland (UK) and Denmark (DK) were studied, and a common method was developed for undertaking farm inventories and the derivation of farm N balances, N surpluses and for evaluating uncertainty for the 222 farms and 11 440 ha of farmland included in the study. In all landscapes, a large variation in the farm N surplus was found, and thereby a large potential for reductions. The highest average N surpluses were found in the most livestock-intensive landscapes of IT, FR, and NL; on average 202 ± 28, 179 ± 63 and 178 ± 20 kg N ha-1 yr-1, respectively. All landscapes showed hotspots, especially from livestock farms, including a special UK case with large-scale landless poultry farming. Overall, the average N surplus from the land-based UK farms dominated by extensive sheep and cattle grazing was only 31 ± 10 kg N ha-1 yr-1, but was similar to the N surplus of PL and DK (122 ± 20 and 146 ± 55 kg N ha-1 yr-1, respectively) when landless poultry farming was included. We found farm N balances to be a useful indicator for N losses and the potential for improving N management. Significant correlations to N surplus were found, both with ammonia air concentrations and nitrate concentrations in soils and groundwater, measured during the period of N management data collection in the landscapes from 2007-2009. This indicates that farm N surpluses may be used as an

  19. [Comparison of nitrogen loss via surface runoff from two agricultural catchments in semi-arid North China].

    PubMed

    Lu, Hai-Ming; Yin, Cheng-Qing; Wang, Xia-Hui; Zou, Ying

    2008-10-01

    Nitrogen loss characteristics via surface runoff from two typical agricultural catchments into Yuqiao Reservoir--the important drinking water source area for Tianjin city in semi-arid North China were investigated through two-year in-situ monitoring and indoor chemical analysis. The results showed that annual nitrogen export mainly concentrated in the rainy period between June to September. About 41% of the annual water output and 52% of the annual total nitrogen output took place in two rainfall events with rainfall> 60 mm in Taohuasi catchment (T catchment), while the distribution of water and nitrogen export among various rainfalls in Caogezhuang catchment (C catchment) was smooth. The rainfall thresholds for the appearance of water and nitrogen export from the outlet of T catchment and C catchment were 20 mm and 10 mm. The mean annual runoff coefficients of C and T catchments were 0.013 2 and 0.001 6, respectively. The mean annual total nitrogen exports from C catchment and T catchment were 1.048 kg x (hm2 x a)(-1) and 0.158 kg x (hm2 x a)(-1) respectively. The difference of micro-topography, landscape pattern and hydrological pathway between two catchments could explain the nitrogen export gap. Micro-topographical features created by long-term anthropological disturbance decrease the runoff generation ability. The distance between nitrogen source area and the outlet in T catchment was around 1 500 m, while such distance in C catchment was just around 200 m. The short distance added the nitrogen export risk via surface runoff. Road-type hydrological pathway in C catchment could transfer nitrogen into the receiving water via surface runoff directly, while nitrogen could be detained within the pathway by many sink structures such as small stones, vegetated buffer strip and dry ponds in T catchment.

  20. Reducing nitrogen losses through ammonia volatilization and surface runoff to improve apparent nitrogen recovery of double cropping of late rice using controlled release urea.

    PubMed

    Li, Pengfei; Lu, Jianwei; Hou, Wenfeng; Pan, Yonghui; Wang, Yang; Khan, Muhammad Rizwan; Ren, Tao; Cong, Rihuan; Li, Xiaokun

    2017-03-22

    Controlled release fertilizer can reduce nitrogen losses to the environment while increasing grain yield and improving apparent nitrogen recovery (ANR) of rice. However, few studies have evaluated the comparative efficacy of different polymer-coated urea products on nitrogen (N) losses, ANR, and N uptake of rice. A 2-year field experiment was conducted to compare the effects of three different types of polymer-coated urea fertilizer on nitrogen losses through NH3 volatilization and surface runoff to the environment, ANR, grain yield, and N uptake as compared to conventional urea of rice. Six treatments including (1) control with 0 kg N ha(-1) (CK), (2) basal application of urea (Ub), (3) split application (Us) of urea (50% at transplanting, 25% at tillering, and 25% at panicle stages), (4) CRU-1 (polyurethane-coated urea), (5) CRU-2 (degradable polymer-coated urea), and (6) CRU-3 (water-based polymer-coated urea) all applied at 165 kg N ha(-1). It was found that CRU-2 resulted in the highest grain yield and panicle numbers among the N fertilization treatments in 2013 and 2014. Applying CRU could help increase N uptake in rice, reduce N losses through NH3 volatilization and surface runoff, and hence improve ANR. Its single dose can meet the nutrient demand of the rice plant. Controlled release urea could be adopted as an effective mitigation alternative to retard N losses through NH3 volatilization and surface runoff while improving ANR of double cropping of late rice.

  1. Losses of surface runoff, total solids, and nitrogen during bermudagrass establishment on levee embankments.

    PubMed

    Burwell, Robert W; Beasley, Jeffrey S; Gaston, Lewis A; Borst, Steven M; Sheffield, Ron E; Strahan, Ron E; Munshaw, Gregg C

    2011-01-01

    Nutrient and sediment runoff from newly constructed levee embankments pose a threat to water quality during soft armor vegetation establishment. Research was initiated in 2008 and 2009 to evaluate the effect of bermudagrass ( L.) coverage and N source on nutrient and sediment runoff from levee embankments during establishment. Bermudagrass plots were seeded at 195.3 kg pure live seed ha and fertilized at 50 kg N ha using a water-soluble N source, urea or NH-NO, or slow-release N source, S-coated urea (SCU) or urea formaldehyde (UF), with controls unfertilized. Vegetative cover percentage, time until the onset of runoff, runoff volume, and total solids (TS), NO-N, and NH-N concentrations were measured from simulated and natural rainfall events for 70 d in 2008 and 56 d in 2009. Bermudagrass at 90% grass cover delayed the onset of runoff an additional 441 to 538 s and reduced runoff volumes 74 to 84% of that exhibited at 10% grass cover. Nitrogen fertilizers did not accelerate bermudagrass growth sufficiently, however, to reduce TS loading compared with unfertilized bermudagrass in either year of the study. The application of urea and SCU resulted in cumulative N losses of 2.45 and 3.13 kg ha compared with 1.59 kg ha from the unfertilized bermudagrass in 2008, and 1.73 kg ha from NH-NO vs. 0.24 kg ha from controls in 2009. Only UF increased bermudagrass establishment without increasing cumulative N losses compared with unfertilized bermudagrass. Therefore, the benefit of greater erosion and runoff resistance expected from N-accelerated vegetative growth did not occur but had the unintended consequence of higher N losses when water-soluble N and SCU fertilizers were applied.

  2. Assessing regional differences in nitrogen losses from U.S. dairy farms using the integrated farm systems model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) enters and leaves a dairy production system through many pathways and in many forms: undergoing numerous transformations as it passes from feed to animal to milk or manure and back again. Due to the complexity of the dairy system, estimates of N flows and losses require the use of model...

  3. Understanding the Variability in Soybean Nitrogen Fixation across Agroecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional farming practices have uncoupled carbon (C) and nitrogen (N) cycles through the application of inorganic N fertilizers applied in plant available forms at levels that saturate the system. As a result, extensive N losses via leaching and denitrification are having significant environment...

  4. Rewetting effects on soil CO2 flux and nutrients leaching in alpine Kobresia pasture on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Liu, Shibin; Schleuss, Per; Kuzyakov, Yakov

    2015-04-01

    Kobresia pygmaea pastures of the Tibetan Plateau are one of the most important ecosystems around the world due to its large grazing area and very high soil organic carbon storage. Since the last decades grasslands of the TP are highly affected by grassland degradation because of various sedimentary programs and strongly increase grazing pressure. Climate changes (e.g. increased precipitation and temperature) may accelerate this degradation processes by enhancing soil organic matter mineralization and nutrients leaching. We exposed repeated rewetting cycles to test the effects of increased precipitation frequency on CO2 fluxes and leaching on varying K. pygmaea root mats (including: intact root mats (KL); recently died root mats (KD); crust covered root mats (LI)). Two phases were conducted (a) to identify the response of nighttime CO2 flux to changing soil moisture and (b) to investigate the impacts of rewetting cycles on day-, night-, and full day CO2 fluxes together with leaching of carbon (C) and nitrogen (N). Nighttime CO2 fluxes correlated positively with soil moisture, indicating that increasing precipitation will accelerate SOC losses due to increasing mineralization rates. KD showed highest C losses as CO2 efflux and also the highest leaching compared to KL and LI. It indicates that dying of Kobresia root mats (as induced by overgrazing and continuously removal of photosynthetically active shoot biomass) will rapidly decrease SOC storage. The lowest C losses (from soil respiration and DOC leaching) were obtained in the crust covered root mats (LI), because most C losses have already occurred during the early period. Highest N losses (especially NO3-) were obtained in the highly degraded pasture (LI). Due to long-term SOM decomposition of crust covered root mats (LI) in situ, inorganic nitrogen (NO3-) was accumulated in and was leached out during the first rewetting cycles. In contrast, no losses of NH4+ and NO3- occurred for intact Kobresia root mats (KL

  5. [Vertical transporting risk of nitrogen in purple soil affected by surfactant].

    PubMed

    Chen, Yu-cheng; Yang, Zhi-min; Jiang, Ling; Chen, Qing-hu; Gao, Meng

    2010-07-01

    The simulated leaching experiment was conducted to determine the effects of surfactant of sodium dodecyl benzene sulphonate (SDBS) on vertical transporting of nitrogen in purple soil. SDBS could reduce NH4+ -N loss from soil, and the higher concentration of SDBS, the less loss. SDBS could increase NO3- -N loss from soil, and the order of accumulation loss is SDBS100 > SDBS40 > SDBS0 > SDBS5. Lower concentration SDBS decrease TKN loss, but higher concentration SDBS had a reverse effect, and compared with SDBS0, the accumulation loss TKN of SDBS40, SDBS100 increased by 16.8%, 22.36%, respectively. SDBS could affect vertical transporting of nitrogen in purple soil, that is, the significant down-transporting of nitrogen was observed after leaching with SDBS, and the higher concentration of SDBS, the more obviously transporting trend.

  6. Nitrogen

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, ammonia was produced by 15 companies at 26 plants in 16 states in the United States. Of the total ammonia production capacity, 55% was centered in Louisiana, Oklahoma and Texas because of their large reserves of natural gas. US producers operated at 66% of their rated capacity. In descending order, Koch Nitrogen, Terra Industries, CF Industries, Agrium and PCS Nitrogen accounted for 81% of the US ammonia production capacity.

  7. Tradeoffs of modifications of storm water managements systems for nitrogen loss pathways in semi-arid ecosystems

    NASA Astrophysics Data System (ADS)

    Lohse, K. A.; Gallo, E. L.; Brooks, P. D.; Meixner, T.; McIntosh, J. C.

    2013-12-01

    Urbanization is altering hydrologic and nitrogen (N) inputs to streams that may substantially increase nitrogen-containing trace gas emissions to the atmosphere with regional and global consequences. In the semi-arid southwestern US, human modifications of ephemerally dry stream channels interact with hydrologic and nitrogen alterations to lead to extremely high fluxes of nitrous oxide (N2O). Cumulative N2O losses ranged from 0.04 to 0.97 mg N m-2 in 6 hr for rainfall compared to 22.5-59.3 mg N m-2 for flood pulse events. Impervious channels eliminated N trace gas losses but increased delivery of water and N to downstream ecosystems and areas of focused recharge by 6 fold compared to watersheds with greater pervious channel lengths. In contrast, importation of clay into channels increased total N trace gas losses by 8-32 fold relative to more natural sand dominated channels but this result depended on the degree of wetting. Our integrated findings suggest human modification of storm water management systems to impervious channels increases delivery of water and N to downstream navigable waters and areas of focused recharge whereas importation of clay materials leads to higher N trace gas losses and reduced delivery of nitrate. Management will need to address long-term challenges of balancing tradeoffs of greenhouse N gases and N in water supplies, intermediate scale issues of enhancing recharge, and short-term issues of removing water and preventing flooding.

  8. Regional modelling of nitrate leaching from Swiss organic and conventional cropping systems under climate change

    NASA Astrophysics Data System (ADS)

    Calitri, Francesca; Necpalova, Magdalena; Lee, Juhwan; Zaccone, Claudio; Spiess, Ernst; Herrera, Juan; Six, Johan

    2016-04-01

    Organic cropping systems have been promoted as a sustainable alternative to minimize the environmental impacts of conventional practices. Relatively little is known about the potential to reduce NO3-N leaching through the large-scale adoption of organic practices. Moreover, the potential to mitigate NO3-N leaching and thus the N pollution under future climate change through organic farming remain unknown and highly uncertain. Here, we compared regional NO3-N leaching from organic and conventional cropping systems in Switzerland using a terrestrial biogeochemical process-based model DayCent. The objectives of this study are 1) to calibrate and evaluate the model for NO3-N leaching measured under various management practices from three experiments at two sites in Switzerland; 2) to estimate regional NO3-N leaching patterns and their spatial uncertainty in conventional and organic cropping systems (with and without cover crops) for future climate change scenario A1B; 3) to explore the sensitivity of NO3-N leaching to changes in soil and climate variables; and 4) to assess the nitrogen use efficiency for conventional and organic cropping systems with and without cover crops under climate change. The data for model calibration/evaluation were derived from field experiments conducted in Liebefeld (canton Bern) and Eschikon (canton Zürich). These experiments evaluated effects of various cover crops and N fertilizer inputs on NO3-N leaching. The preliminary results suggest that the model was able to explain 50 to 83% of the inter-annual variability in the measured soil drainage (RMSE from 12.32 to 16.89 cm y-1). The annual NO3-N leaching was also simulated satisfactory (RMSE = 3.94 to 6.38 g N m-2 y-1), although the model had difficulty to reproduce the inter-annual variability in the NO3-N leaching losses correctly (R2 = 0.11 to 0.35). Future climate datasets (2010-2099) from the 10 regional climate models (RCM) were used in the simulations. Regional NO3-N leaching

  9. [Nitrogen and phosphorus loss in different land use types and its response to environmental factors in the Three Gorges Reservoir area].

    PubMed

    Zeng, Li-Xiong; Huang, Zhi-Lin; Xiao, Wen-Fa; Tian, Yao-Wu

    2012-10-01

    The control of agricultural non-point source pollution (AGNPS) is an urgent problem to be solved for the ecological environment construction in the Three Gorges Reservoir Area. We analyzed the nitrogen (N) and phosphorus (P) loss and its response to environmental factors through monitoring the nutrient loss in different land use types after returning farmland to forest. The results showed that: 1) The variability of nutrient concentration loss was strong in different land use types under different rainfall conditions, and the variability in the concentration of available nutrient was much higher than that of total nutrient; 2) Compared to farmland, the annual phosphorus loss of different land use types was reduced by 84.53% - 91.61% after returning farmland to forest; the reduction of annual nitrogen loss was not significant except Chinese chestnut forest (Castanea mollissima) and arbor forest, and the nitrogen loss was much higher than the phosphorus loss in all land use types; 3) The particle phosphorus and nitrate nitrogen (NO3(-)-N) were the main forms of the phosphorus and nitrogen loss, respectively; 4) The nutrient loss of tea garden (Camellia sinensis) and bamboo forest (Phyllostachys pubescens) showed a good correlation with precipitation, and the correlation of phosphorus was better than that of nitrogen, but there was no significant relation with the rainfall intensity; 5) The coverage of vegetation, tree layer and litter had a great influence on the loss of total nitrogen (TN). NO3(-)-N loss was highly influenced by the ammonium nitrogen (NH4(+)-N) content in the surface soil, and P loss mainly by the total phosphorus (TP) and sand content in the soil.

  10. Evidence of Nitrogen Loss from Anaerobic Ammonium Oxidation Coupled with Ferric Iron Reduction in an Intertidal Wetland.

    PubMed

    Li, Xiaofei; Hou, Lijun; Liu, Min; Zheng, Yanling; Yin, Guoyu; Lin, Xianbiao; Cheng, Lv; Li, Ye; Hu, Xiaoting

    2015-10-06

    Anaerobic ammonium oxidation coupled with nitrite reduction is an important microbial pathway of nitrogen removal in intertidal wetlands. However, little is known about the role of anaerobic ammonium oxidation coupled with ferric iron reduction (termed Feammox) in intertidal nitrogen cycling. In this study, sediment slurry incubation experiments were combined with an isotope-tracing technique to examine the dynamics of Feammox and its association with tidal fluctuations in the intertidal wetland of the Yangtze Estuary. Feammox was detected in the intertidal wetland sediments, with potential rates of 0.24-0.36 mg N kg(-1) d(-1). The Feammox rates in the sediments were generally higher during spring tides than during neap tides. The tidal fluctuations affected the growth of iron-reducing bacteria and reduction of ferric iron, which mediated Feammox activity and the associated nitrogen loss from intertidal wetlands to the atmosphere. An estimated loss of 11.5-18 t N km(-2) year(-1) was linked to Feammox, accounting for approximately 3.1-4.9% of the total external inorganic nitrogen transported into the Yangtze Estuary wetland each year. Overall, the co-occurrence of ferric iron reduction and ammonium oxidation suggests that Feammox can act as an ammonium removal mechanism in intertidal wetlands.

  11. Feasibility of incorporating the nitrogen-loss inhibitors dicyandiamide, thiourea, phenyl phosphorodiamidate, and potassium ethyl xanthate into granular urea

    SciTech Connect

    Gautney, J.; Kim, Y.K.; Gagen, P.M.

    1983-01-01

    Laboratory tests were conducted to determine the feasibility of incorporating the nitrogen loss inhibitors dicyandiamide (DCD), thiourea (TU), phenyl phosphorodiamidate (PPDA), and potassium ethyl xanthate (PEX) into granular urea. Tests were made to determine the stabilities, solubilities, and dissolution rates of the inhibitors in urea melts and urea solutions; to determine the effect of inhibitor addition on the rate of weight loss and qualitative composition of volatiles evolving from urea melts; to determine the melting point diagrams for the urea inhibitor systems; and to determine the heat of fusion for the urea-inhibitor mixtures.

  12. Nitrogen

    USGS Publications Warehouse

    Apodaca, L.E.

    2012-01-01

    Ammonia was produced by 12 companies at 27 plants in 15 states in the United States during 2011. Sixty-one percent of total U.S. ammonia production capacity was centered in Louisiana, Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2011, U.S. producers operated at about 84 percent of their rated capacity (excluding plants that were idle for the entire year). Four companies — CF Industries Holdings Inc.; Koch Nitrogen Co.; PCS Nitrogen Inc. and Agrium Inc., in descending order — accounted for 77 percent of the total U.S. ammonia production capacity.

  13. The fate of nitrogen fertilizer added to soy-maize agriculture in the Amazon basin: Quantifying N2O flux and losses to groundwater

    NASA Astrophysics Data System (ADS)

    Jankowski, K. J.; Neill, C.; Davidson, E. A.; Macedo, M.; Costa, C., Jr.; Galford, G. L.; Coe, M. T.; O'Connell, C.; Brando, P. M.; Lefebvre, P.; Maracahipes, L.; Nunes, D.; McHorney, R.

    2015-12-01

    Deforestation and agricultural intensification are rapidly changing the landscape of southeastern Amazonia. With international pressure to reduce deforestation, many Brazilian farms have opted to intensify agriculture to a system of soybean-maize double cropping, and it has expanded rapidly in the last 10 years. Maize agriculture requires additional nitrogen (N) fertilizers, whose downstream fate is currently unknown. Typical fertilizer application rates range from 30-120 kg N ha-1, and have the potential to introduce large amounts of N to ecosystems of the Amazon basin, which can alter greenhouse gas flux and nutrient transport to groundwater and streams. Little data on the fate of added fertilizers are available in the tropics in general, especially in this critical region of agricultural expansion. Therefore, we established a field-scale experiment to evaluate the fate of N fertilizer on Tanguro Ranch in Mato Grosso, Brazil, a region of rapidly expanding soy-maize double cropping. We measured greenhouse gas fluxes (N2O, CO2, and CH4), soil N content, losses to groundwater, and corn productivity across five levels of fertilizer addition (0-200 kg N ha-1) throughout an entire growing season. We found that N2O flux increased with fertilizer addition, but was only significantly higher at 200 kg N ha-1. Surface soil N content increased after fertilizer addition, but decreased within weeks, and was quickly observed in subsurface soil water. Modeling results that scale these findings to the state of Mato Grosso suggest that this land use transition could create a substantial new source of N2O and CO2 to the atmosphere and has the potential to leach N fertilizer into groundwater and downstream. It is important to maintain forest code policies that minimize these impacts.

  14. Runoff, nitrogen (N) and phosphorus (P) losses from purple slope cropland soil under rating fertilization in Three Gorges Region.

    PubMed

    Bouraima, Abdel-Kabirou; He, Binghui; Tian, Taiqiang

    2016-03-01

    Soil erosion along with soil particles and nutrients losses is detrimental to crop production. We carried out a 5-year (2010 to 2014) study to characterize the soil erosion and nitrogen and phosphorus losses caused by rainfall under different fertilizer application levels in order to provide a theoretical evidence for the agricultural production and coordinate land management to improve ecological environment. The experiment took place under rotation cropping, winter wheat-summer maize, on a 15° slope purple soil in Chongqing (China) within the Three Gorges Region (TGR). Four treatments, control (CK) without fertilizer, combined manure with chemical fertilizer (T1), chemical fertilization (T2), and chemical fertilizer with increasing fertilization (T3), were designed on experimental runoff plots for a long-term observation aiming to study their effects on soil erosion and nutrients losses. The results showed that fertilization reduced surface runoff and nutrient losses as compared to CK. T1, T2, and T3, compared to CK, reduced runoff volume by 35.7, 29.6, and 16.8 %, respectively and sediment yield by 40.5, 20.9, and 49.6 %, respectively. Regression analysis results indicated that there were significant relationships between soil loss and runoff volume in all treatments. The combined manure with chemical fertilizer (T1) treatment highly reduced total nitrogen and total phosphorus losses by 41.2 and 33.33 %, respectively as compared with CK. Through this 5-year experiment, we can conclude that, on the sloping purple soil, the combined application of manure with fertilizer is beneficial for controlling runoff sediments losses and preventing soil erosion.

  15. Nitrogen depletion in the fission yeast Schizosaccharomyces pombe causes nucleosome loss in both promoters and coding regions of activated genes

    PubMed Central

    Kristell, Carolina; Orzechowski Westholm, Jakub; Olsson, Ida; Ronne, Hans; Komorowski, Jan; Bjerling, Pernilla

    2010-01-01

    Gene transcription is associated with local changes in chromatin, both in nucleosome positions and in chemical modifications of the histones. Chromatin dynamics has mostly been studied on a single-gene basis. Those genome-wide studies that have been made primarily investigated steady-state transcription. However, three studies of genome-wide changes in chromatin during the transcriptional response to heat shock in the budding yeast Saccharomyces cerevisiae revealed nucleosome eviction in promoter regions but only minor effects in coding regions. Here, we describe the short-term response to nitrogen starvation in the fission yeast Schizosaccharomyces pombe. Nitrogen depletion leads to a fast induction of a large number of genes in S. pombe and is thus suitable for genome-wide studies of chromatin dynamics during gene regulation. After 20 min of nitrogen removal, 118 transcripts were up-regulated. The distribution of regulated genes throughout the genome was not random; many up-regulated genes were found in clusters, while large parts of the genome were devoid of up-regulated genes. Surprisingly, this up-regulation was associated with nucleosome eviction of equal magnitudes in the promoters and in the coding regions. The nucleosome loss was not limited to induction by nitrogen depletion but also occurred during cadmium treatment. Furthermore, the lower nucleosome density persisted for at least 60 min after induction. Two highly induced genes, urg1+ and urg2+, displayed a substantial nucleosome loss, with only 20% of the nucleosomes being left in the coding region. We conclude that nucleosome loss during transcriptional activation is not necessarily limited to promoter regions. PMID:20086243

  16. Genotypic trait variation modifies effects of climate warming and nitrogen deposition on litter mass loss and microbial respiration.

    PubMed

    Hines, Jes; Reyes, Marta; Mozder, Thomas J; Gessner, Mark O

    2014-12-01

    Intraspecific variation in genotypically determined traits can influence ecosystem processes. Therefore, the impact of climate change on ecosystems may depend, in part, on the distribution of plant genotypes. Here we experimentally assess effects of climate warming and excess nitrogen supply on litter decomposition using 12 genotypes of a cosmopolitan foundation species collected across a 2100 km latitudinal gradient and grown in a common garden. Genotypically determined litter-chemistry traits varied substantially within and among geographic regions, which strongly affected decomposition and the magnitude of warming effects, as warming accelerated litter mass loss of high-nutrient, but not low-nutrient, genotypes. Although increased nitrogen supply alone had no effect on decomposition, it strongly accelerated litter mass loss of all genotypes when combined with warming. Rates of microbial respiration associated with the leaf litter showed nearly identical responses as litter mass loss. These results highlight the importance of interactive effects of environmental factors and suggest that loss or gain of genetic variation associated with key phenotypic traits can buffer, or exacerbate, the impact of global change on ecosystem process rates in the future.

  17. Nitrogen

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Ammonia was produced by 15 companies at 25 plants in 16 states in the United States during 2006. Fifty-seven percent of U.S. ammonia production capacity was centered in Louisiana, Oklahoma and Texas because of their large reserves of natural gas, the dominant domestic feedstock. In 2006, U.S. producers operated at about 72 percent of their rated capacity (excluding plants that were idle for the entire year). Five companies, Koch Nitrogen, Terra Industries, CF Industries, PCS Nitro-gen, and Agrium, in descending order, accounted for 79 percent U.S. ammonia production capacity. The United States was the world's fourth-ranked ammonia producer and consumer following China, India and Russia. Urea, ammonium nitrate, ammonium phosphates, nitric acid and ammonium sulfate were the major derivatives of ammonia in the United States, in descending order of importance.

  18. Nitrogen

    USGS Publications Warehouse

    Apodaca, L.E.

    2010-01-01

    Ammonia was produced by 13 companies at 23 plants in 16 states during 2009. Sixty percent of all U.S. ammonia production capacity was centered in Louisiana. Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2009, U.S. producers operated at about 83 percent of their rated capacity (excluding plants that were idle for the entire year). Five companies — Koch Nitrogen Co.; Terra Industries Inc.; CF Industries Inc.; PCS Nitrogen Inc. and Agrium Inc., in descending order — accounted for 80 percent of the total U.S. ammonia production capacity. U.S. production was estimated to be 7.7 Mt (8.5 million st) of nitrogen (N) content in 2009 compared with 7.85 Mt (8.65 million st) of N content in 2008. Apparent consumption was estimated to have decreased to 12.1 Mt (13.3 million st) of N, a 10-percent decrease from 2008. The United States was the world's fourth-ranked ammonia producer and consumer following China, India and Russia. Urea, ammonium nitrate, ammonium phosphates, nitric acid and ammonium sulfate were the major derivatives of ammonia in the United States, in descending order of importance.

  19. Channeling effects observed in energy-loss spectra of nitrogen ions scattered off a Pt(110) surface

    NASA Astrophysics Data System (ADS)

    Robin, A.; Heiland, W.; Jensen, J.; Juaristi, J. I.; Arnau, A.

    2001-11-01

    We present measured energy-loss spectra of nitrogen ions, which are scattered off a (1×2) missing row reconstructed Pt(110) single-crystal surface. The primary energy is varied from below 1 keV up to above 1 MeV, i.e., 0.04v0loss values obtained from trajectory and stopping power calculations of charged particles scattered under grazing incidence conditions from metallic surfaces. The stopping power is calculated using the scattering theory formalism. Different trajectory classes are found by the calculations and assigned to different contributions in the energy-loss spectra. Regarding the simplicity of the presented model the agreement with the experiment is good.

  20. Controlling nitrogen migration through micro-nano networks.

    PubMed

    Cai, Dongqing; Wu, Zhengyan; Jiang, Jiang; Wu, Yuejin; Feng, Huiyun; Brown, Ian G; Chu, Paul K; Yu, Zengliang

    2014-01-14

    Nitrogen fertilizer unabsorbed by crops eventually discharges into the environment through runoff, leaching and volatilization, resulting in three-dimensional (3D) pollution spanning from underground into space. Here we describe an approach for controlling nitrogen loss, developed using loss control fertilizer (LCF) prepared by adding modified natural nanoclay (attapulgite) to traditional fertilizer. In the aqueous phase, LCF self-assembles to form 3D micro/nano networks via hydrogen bonds and other weak interactions, obtaining a higher nitrogen spatial scale so that it is retained by a soil filtering layer. Thus nitrogen loss is reduced and sufficient nutrition for crops is supplied, while the pollution risk of the fertilizer is substantially lowered. As such, self-fabrication of nano-material was used to manipulate the nitrogen spatial scale, which provides a novel and promising approach for the research and control of the migration of other micro-scaled pollutants in environmental medium.

  1. Potential use of the N2/Ar ratio as a constraint on the oceanic fixed nitrogen loss

    NASA Astrophysics Data System (ADS)

    Shigemitsu, M.; Gruber, N.; Oka, A.; Yamanaka, Y.

    2016-04-01

    Using a global ocean biogeochemical model, we investigate the suitability of the N2/Ar supersaturation ratio (ΔN2/Ar) as a tracer of marine nitrogen fixation and denitrification, i.e., the main biological processes that add or remove fixed nitrogen to or from the ocean. In a series of factorial simulations, we demonstrate that, in regions away from the oxygen minimum zones (OMZs), the ΔN2/Ar characteristics are mostly determined by benthic denitrification occurring in the deep ocean with minor contributions from benthic and water column denitrification at shallower depths. In the OMZs, the subsurface maxima of ΔN2/Ar are mainly determined by water column denitrification. In contrast, nitrogen fixation has little impact on ΔN2/Ar owing to the rapid loss of the N2 supersaturation signal through air-sea exchange. We thus conclude that ΔN2/Ar can act as a powerful constraint on water column and benthic denitrification occurring in intermediate to deep waters, but it cannot be used to estimate nitrogen fixation. A comparison between the currently very limited observations of the ΔN2/Ar with our model results shows an acceptable level of agreement, suggesting that the model's prescribed rates and distributions of benthic and water column denitrification (i.e., 140 and 52 Tg N yr-1, respectively) are reasonable and confirm the results derived from other constraints.

  2. Identification and testing of early indicators for N leaching from urine patches.

    PubMed

    Vogeler, Iris; Cichota, Rogerio; Snow, Val

    2013-11-30

    Nitrogen leaching from urine patches has been identified as a major source of nitrogen loss under intensive grazing dairy farming. Leaching is notoriously variable, influenced by management, soil type, year-to-year variation in climate and timing and rate of urine depositions. To identify early indicators for the risk of N leaching from urine patches for potential usage in a precision management system, we used the simulation model APSIM (Agricultural Production Systems SIMulator) to produce an extensive N leaching dataset for the Waikato region of New Zealand. In total, nearly forty thousand simulation runs with different combinations of soil type and urine deposition times, in 33 different years, were done. The risk forecasting indicators were chosen based on their practicality: being readily measured on farm (soil water content, temperature and pasture growth) or that could be centrally supplied to farms (such as actual and forecast weather data). The thresholds of the early indicators that are used to forecast a period for high risk of N leaching were determined via classification and regression tree analysis. The most informative factors were soil temperature, pasture dry matter production, and average soil water content in the top soil over the two weeks prior to the urine N application event. Rainfall and air temperature for the two weeks following urine deposition were also important to fine-tune the predictions. The identified early indicators were then tested for their potential to predict the risk of N leaching in two typical soils from the Waikato region in New Zealand. The accuracy of the predictions varied with the number of indicators, the soil type and the risk level, and the number of correct predictions ranged from about 45 to over 90%. Further expansion and fine-tuning of the indicators and the development of a practical N risk tool based on these indicators is needed.

  3. A modeling study on mitigation of N2O emissions and NO3 leaching at different agricultural sites across Europe using LandscapeDNDC.

    PubMed

    Molina-Herrera, Saúl; Haas, Edwin; Klatt, Steffen; Kraus, David; Augustin, Jürgen; Magliulo, Vincenzo; Tallec, Tiphaine; Ceschia, Eric; Ammann, Christof; Loubet, Benjamin; Skiba, Ute; Jones, Stephanie; Brümmer, Christian; Butterbach-Bahl, Klaus; Kiese, Ralf

    2016-05-15

    The identification of site-specific agricultural management practices in order to maximize yield while minimizing environmental nitrogen losses remains in the center of environmental pollution research. Here, we used the biogeochemical model LandscapeDNDC to explore different agricultural practices with regard to their potential to reduce soil N2O emissions and NO3 leaching while maintaining yields. In a first step, the model was tested against observations of N2O emissions, NO3 leaching, soil micrometeorology as well as crop growth for eight European cropland and grassland sites. Across sites, LandscapeDNDC predicts very well mean N2O emissions (r(2)=0.99) and simulates the magnitude and general temporal dynamics of soil inorganic nitrogen pools. For the assessment of site-specific mitigation potentials of environmental nitrogen losses a Monte Carlo optimization technique considering different agricultural management options (i.e., timing of planting, harvest and fertilization, amount of applied fertilizer as well as residue management) was used. The identified optimized field management practices reduce N2O emissions and NO3 leaching from croplands on average by 21% and 31%, respectively. Likewise, average reductions of 55% for N2O emissions and 16% for NO3 leaching are estimated for grasslands. For mitigating environmental loss - while maintaining yield levels - it was most important to reduce fertilizer application rates by in average 10%. Our analyses indicate that yield scaled N2O emissions and NO3 leaching indicate possible improvements of nitrogen use efficiencies in European farming systems. Moreover, the applied optimization approach can be used also in a prognostic way to predict optimal timings and fertilization options (rates and splitting) upon accurate weather forecasts combined with the knowledge of modeled soil nutrient availability and plant nitrogen demand.

  4. PEP Support: Laboratory Scale Leaching and Permeate Stability Tests

    SciTech Connect

    Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.; Buchmiller, William C.

    2010-05-21

    This report documents results from a variety of activities requested by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The activities related to caustic leaching, oxidative leaching, permeate precipitation behavior of waste as well as chromium (Cr) leaching are: • Model Input Boehmite Leaching Tests • Pretreatment Engineering Platform (PEP) Support Leaching Tests • PEP Parallel Leaching Tests • Precipitation Study Results • Cr Caustic and Oxidative Leaching Tests. Leaching test activities using the PEP simulant provided input to a boehmite dissolution model and determined the effect of temperature on mass loss during caustic leaching, the reaction rate constant for the boehmite dissolution, and the effect of aeration in enhancing the chromium dissolution during caustic leaching. Other tests were performed in parallel with the PEP tests to support the development of scaling factors for caustic and oxidative leaching. Another study determined if precipitate formed in the wash solution after the caustic leach in the PEP. Finally, the leaching characteristics of different chromium compounds under different conditions were examined to determine the best one to use in further testing.

  5. Leaching of nitroso rubber material removes uncured polymer

    NASA Technical Reports Server (NTRS)

    Bratfisch, W. A.; Gonzalez, R.

    1972-01-01

    New leaching process removes uncured polymer from nitroso rubber, elastomer used in presence of nitrogen tetroxide. Uncured portion is removed by controlled soaking of polymer slab in Freon TF. Leaching with Freon TF prevents nitroso rubber from adhering to adjoining surfaces and limiting its usefulness in either static or dynamic applications.

  6. 4R Water quality impacts: An assessment and synthesis of forty years of drainage nitrogen losses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The intersection of agricultural drainage and nutrient mobility in the environment has led to multi-scale water quality concerns. This work reviewed and quantitatively analyzed nearly 1300 site-years of drainage nitrogen load data to develop a more comprehensive understanding of the impacts of 4Rs ...

  7. Partial nitrogen loss in SrTaO2N and LaTiO2N oxynitride perovskites

    NASA Astrophysics Data System (ADS)

    Chen, Daixi; Habu, Daiki; Masubuchi, Yuji; Torii, Shuki; Kamiyama, Takashi; Kikkawa, Shinichi

    2016-04-01

    SrTaO2N heated in a helium atmosphere began to release nitrogen of approximately 30 at% at 950 °C while maintaining the perovskite structure and its color changed from orange to dark green. Then it decomposed above 1200 °C to a black mixture of Sr1.4Ta0.6O2.73, Ta2N, and Sr5Ta4O15. The second decomposition was not clearly observed when SrTaO2N was heated in a nitrogen atmosphere below 1550 °C. After heating at 1500 °C for 3 h under a 0.2 MPa nitrogen atmosphere, the perovskite product became dark green and conductive. Structure refinement results suggested that the product was a mixture of tetragonal and cubic perovskites with a decreased ordering of N3-/O2-. The sintered body was changed to an n-type semiconductor after a partial loss of nitrogen to be reduced from the originally insulating SrTaO2N perovskite lattice. LaTiO2N was confirmed to have a similar cis-configuration of the TiO4N2 octahedron as that of TaO4N2 in SrTaO2N. It also released some of its nitrogen at 800 °C changing its color from brown to black and then decomposed to a mixture of LaTiO3, La2O3, and TiN at 1100 °C. These temperatures are lower than those in SrTaO2N.

  8. Water quality and nitrogen mass loss from anaerobic lagoon columns receiving pretreated influent

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Control methods are needed to abate ammonia losses from swine anaerobic lagoons to reduce contribution of confined swine operations to air pollution. In a 15-month meso-scale column study, we evaluated the effect of manure pretreatment on water quality, reduction of N losses, and sludge accumulation...

  9. [Nitrogen Losses Under the Action of Different Land Use Types of Small Catchment in Three Gorges Region].

    PubMed

    Chen, Cheng-long; Gao, Ming; Ni, Jiu-pai; Xie, De-ti; Deng, Hua

    2016-05-15

    As an independent water-collecting area, small catchment is the source of non-point source pollution in Three Gorges Region. Choosing 3 kinds of the most representative land-use types and using them to lay monitoring points of overland runoff within the small catchment of Wangjiagou in Fuling of Three Gorges Region, the author used the samples of surface runoff collected through the twelve natural rainfalls from May to December to analyze the feature of spatial-temporal change of Nitrogen's losses concentrations under the influence of different land use types and the hillslopes and small catchments composed by those land use types, revealing the relation between different land-use types and Nitrogen's losses of small catchments in Three Gorges Region. The result showed: the average losses concentration of TN showed the biggest difference for different land use types during the period of spring crops, and the average value of dry land was 1. 61 times and 6.73 times of the values of interplanting field of mulberry and paddy field, respectively; the change of the losses concentration of TN was most conspicuous in the 3 periods of paddy field. The main element was NO₃⁻-N, and the relation between TN and NO₃⁻-N showed a significant linear correlation. TN's and NO₃⁻-N's losses concentrations were significantly and positively correlated with the area ratio of corn and mustard, but got a significant negative correlation with the area ratio of paddy and mulberry; NH₄⁺-N's losses concentrations got a significant positive correlation with the area ratio of mustard. Among all the hillslopes composed by different land use types, TN's average losses concentration of surface runoff of the hillslope composed by interplantating field of mulberry and paddy land during the three periods was the lowest, and the values were 2.55, 11.52, 8.58 mg · L⁻¹, respectively; the hillslope of rotation plough land of corn and mustard had the maximum value, and the values were

  10. Integrating soil and weather information into canopy sensor algorithms for improved corn nitrogen rate recommendation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn production can be often limited by the loss of nitrogen (N) due to leaching, volatilization and denitrification. The use of canopy sensors for making in-season N fertilizer applications has been proven effective in matching plant N requirements with periods of rapid N uptake (V7-V11), reducing ...

  11. Nitrate leaching, water-use efficiency and yield of corn with different irrigation and nitrogen management systems in coastal plains, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation management for corn (Zea mays L.) production on the typical low water holding capacity soil of the southeastern USA needs to be improved to increase irrigation efficiency and reduce losses of nitrate from fields. A three-year (2012-2014) field study was conducted to compare the effects of...

  12. Responses of nitrous oxide emissions and nitrate leaching to farm field management, climate, and soil characteristics: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Heffernan, J. B.; Eagle, A.; Bernhardt, E. S.; Olander, L. P.

    2014-12-01

    Agriculture is a major source of both nitrous oxide (N2O) to the atmosphere and nitrate (NO3-) to surface and groundwaters, but synergies and tradeoffs between these nitrogen (N) loss pathways in response to agricultural practices are not well understood. We conducted a meta-analysis of both N2O emissions and NO3- leaching losses to quantify their individual responses to fertilization rate, tillage, and other practices. Overall, we assembled over 40 studies that reported fertilization rate, yield, and either N2O emissions or NO3- leaching losses over the growing season from North American corn fields. Our complete database ultimately included over 600 observations of N2O emissions or NO3- leaching. Notably, we found no individual studies that reported both NO3- leaching and N2O emissions. We used multiple regression to quantify the response of N loss pathways to fertilization rate; rotation crop and tillage practice; and climate and soil type. We also included yield as a predictor to better account for the magnitude of surplus N. We found insufficient data to address effects of fertilizer placement, timing and source. On a mass basis, NO3- losses were far greater than N2O emissions. Both NO3- leaching and N2O emissions exhibited positive relationships with fertilizer rate and surplus N, but the responses of N loss pathways to environmental conditions and to various management practices varied considerably. These results suggest that minimizing excess fertilizer application will both improve water quality and reduce greenhouse gas emissions, but that other practices such as tillage induce tradeoffs between these N loss pathways.

  13. Modeling Nitrogen Losses in Conventional and Advanced Soil-Based Onsite Wastewater Treatment Systems under Current and Changing Climate Conditions

    PubMed Central

    Cooper, Jennifer

    2016-01-01

    Most of the non-point source nitrogen (N) load in rural areas is attributed to onsite wastewater treatment systems (OWTS). Nitrogen compounds cause eutrophication, depleting the oxygen in marine ecosystems. OWTS rely on physical, chemical and biological soil processes to treat wastewater and these processes may be affected by climate change. We simulated the fate and transport of N in different types of OWTS drainfields, or soil treatment areas (STA) under current and changing climate scenarios, using 2D/3D HYDRUS software. Experimental data from a mesocosm-scale study, including soil moisture content, and total N, ammonium (NH4+) and nitrate (NO3-) concentrations, were used to calibrate the model. A water content-dependent function was used to compute the nitrification and denitrification rates. Three types of drainfields were simulated: (1) a pipe-and-stone (P&S), (2) advanced soil drainfields, pressurized shallow narrow drainfield (PSND) and (3) Geomat (GEO), a variation of SND. The model was calibrated with acceptable goodness-of-fit between the observed and measured values. Average root mean square error (RSME) ranged from 0.18 and 2.88 mg L-1 for NH4+ and 4.45 mg L-1 to 9.65 mg L-1 for NO3- in all drainfield types. The calibrated model was used to estimate N fluxes for both conventional and advanced STAs under current and changing climate conditions, i.e. increased soil temperature and higher water table. The model computed N losses from nitrification and denitrification differed little from measured losses in all STAs. The modeled N losses occurred mostly as NO3- in water outputs, accounting for more than 82% of N inputs in all drainfields. Losses as N2 were estimated to be 10.4% and 9.7% of total N input concentration for SND and Geo, respectively. The highest N2 losses, 17.6%, were estimated for P&S. Losses as N2 increased to 22%, 37% and 21% under changing climate conditions for Geo, PSND and P&S, respectively. These findings can provide practitioners

  14. Critical factors affecting field-scale losses of nitrogen and phosphorus in spring snowmelt runoff in the canadian prairies.

    PubMed

    Liu, Kui; Elliott, Jane A; Lobb, David A; Flaten, Don N; Yarotski, Jim

    2013-01-01

    A long-term, field-scale study in southern Manitoba, Canada, was used to identify the critical factors controlling yearly transport of nitrogen (N) and phosphorus (P) by snowmelt runoff. Flow monitoring and water sampling for total and dissolved N and P were performed at the edge of field. The flow-weighted mean concentrations and loads of N and P for the early (the first half of yearly total volume of snowmelt runoff), late (the second half of yearly total volume of snowmelt runoff), and yearly snowmelt runoff were calculated as response variables. A data set of management practices, weather variables, and hydrologic variables was generated and used as predictor variables. Partial least squares regression analysis indicated that critical factors affecting the water chemistry of snowmelt runoff depended on the water quality variable and stage of runoff. Management practices within each year, such as nitrogen application rate, number of tillage passes, and residue burial ratio, were critical factors for flow-weighted mean concentration of N, but not for P concentration or nutrient loads. However, the most important factors controlling nutrient concentrations and loads were those related to the volume of runoff, including snow water equivalent, flow rate, and runoff duration. The critical factors identified for field-scale yearly snowmelt losses provide the basis for modeling of nutrient losses in southern Manitoba and potentially throughout areas with similar climate in the northern Great Plains region, and will aid in the design of effective practices to reduce agricultural nonpoint nutrient pollution in downstream waters.

  15. Nitrogen gas propagation in a liquid helium cooled vacuum tube following a sudden vacuum loss

    NASA Astrophysics Data System (ADS)

    Dhuley, R. C.; Van Sciver, S. W.

    2017-02-01

    We present experimental measurements and analysis of propagation of the nitrogen gas that was vented to a high vacuum tube immersed in liquid helium (LHe). The scenario resembles accidental venting of atmospheric air to a SRF beam-line and was investigated to understand how the in-flowing air would propagate in such geometry. The gas front propagation speed in the tube was measured using pressure probes and thermometers installed at regular intervals over the tube length. The experimental data show the front speed to decrease along the vacuum tube. The empirical and analytical models developed to characterize the front deceleration are summarized.

  16. Slow release coating remedy for nitrogen loss from conventional urea: a review.

    PubMed

    Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar

    2016-03-10

    Developing countries are consuming major part of the global urea production with an anticipated nitrogen use efficiency of 20 to 35%. The release of excess nitrogen in the soil is not only detrimental to the environment but also lessens the efficiency of the conventional urea. The urea performance can be enhanced by encapsulating it with slow release coating materials and synchronizing the nutrients' release with the plant up-taking. However, the present cost of most of the coated fertilizers is considerably higher than the conventional fertilizers. The high cost factor prevents their widespread use in mainstream agriculture. This paper documents a review of literature related to the global urea market, issues pertaining to the conventional urea use, natural and synthetic materials for slow release urea and fluidized bed spray coating process. The aim of the current review is to develop technical understanding of the conventional and non-conventional coating materials and associated spray coating mechanism for slow release urea production. The study also investigated the potential of starch as the coating material in relation to the coatings tested previously for controlled release fertilizers.

  17. Carbon and nitrogen loss in windblown dust on the Columbia Plateau

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erosion from windstorms may lead to high nutrient loss in fields and cause environmental degradation as a result of suspension in the atmosphere or deposition in surface water systems. In particular, high wind weather events can emit particulates from tilled agricultural soils on the Columbia P...

  18. Nitrate loss in subsurface drainage and corn yield as affected by timing of sidedress nitrogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using chlorophyll meters, crop sensors, or aerial photography to fine-tune sidedress N application rates have been proposed for optimizing and perhaps reducing overall N fertilizer use on corn (Zea mays L.) and thereby improving water quality by reducing NO3 losses to surface and ground waters. Howe...

  19. The influence of photochemical fractionation on the evolution of the nitrogen isotope ratios - detailed analysis of current photochemical loss rates

    NASA Astrophysics Data System (ADS)

    Mandt, K. E.; Waite, J. H., Jr.; Westlake, J.; Magee, B.; Liang, M. C.; Bell, J.

    2012-04-01

    Tracking the evolution of molecular nitrogen over geologic time scales requires an understanding of the loss rates of both isotopologues (14N2 and 14N15N) as a function of time (e.g. Mandt et al., 2009). The relative loss rates, if different, “fractionate” the isotopes so that the ratios change as a function of time, and rate at which the ratio changes due to a loss process is determined by the “fractionation factor.” Photochemistry is known to fractionate the nitrogen isotopes in Titan’s atmosphere by preferentially removing the heavy isotope from the molecular nitrogen inventory and increasing the ratio (heavy/light) in one of the primary photochemical products, HCN. This fractionation occurs due to a selective shielding during photodissociation where the photons that dissociate 14N15N penetrate deeper into the atmosphere (Liang et al., 2007) than the photons that dissociate 14N14N. Two methods can be used to determine the photochemical fractionation factor, f. The first approach for calculating f is based on the isotopic ratios of the photochemical source and product, as measured by the Huygens Gas Chromatograph Mass Spectrometer (GCMS) (Niemann et al., 2010) and the Cassini Infrared Spectrometer (CIRS) (Vinatier et al., 2007), respectively. The second method uses the loss rates and the ratio of the source and requires detailed photochemical modeling to ensure that the loss rates are calculated accurately. We compare these two methods for calculating the photochemical fractionation factor for N2 by using measurements of the isotopic ratios of N2 and HCN combined with an updated coupled ion-neutral-thermal model (De la Haye et al., 2008). We find that accurate magnetospheric electron fluxes and a rotating model that accounts for diurnal variations are essential for accurate calculations of the HCN densities and for determination of the fractionation factor through photochemical modeling. References: De La Haye, V., J. H. Waite, Jr., T. E. Cravens, I. P

  20. Nitrogen and phosphorus use efficiencies and losses in the food chain in China at regional scales in 1980 and 2005.

    PubMed

    Ma, L; Velthof, G L; Wang, F H; Qin, W; Zhang, W F; Liu, Z; Zhang, Y; Wei, J; Lesschen, J P; Ma, W Q; Oenema, O; Zhang, F S

    2012-09-15

    Crop and animal production in China has increased significantly during the last decades, but at the cost of large increases in nitrogen (N) and phosphorus (P) losses, which contribute to ecosystem degradation and human health effects. This information is largely based on scattered field experiments, surveys and national statistics. As a consequence, there is as yet no comprehensive understanding of the changes in N and P cycling and losses at regional and national scales. Here, we present the results of an integrated assessment of the N and P use efficiencies (NUE and PUE) and N and P losses in the chain of crop and animal production, food processing and retail, and food consumption at regional scale in 1980 and 2005, using a uniform approach and databases. Our results show that the N and P costs of food production-consumption almost doubled between 1980 and 2005, but with large regional variation. The NUE and PUE of crop production decreased dramatically, while NUE and PUE in animal production increased. Interestingly, NUE and PUE of the food processing sector decreased from about 75% to 50%. Intake of N and P per capita increased, but again with large regional variation. Losses of N and P from agriculture to atmosphere and water bodies increased in most regions, especially in the east and south of the country. Highest losses were estimated for the Beijing and Tianjin metropolitan regions (North China), Pearl River Delta (South China) and Yangzi River Delta (East China). In conclusion, the changes and regional variations in NUE and PUE in the food chain of China are large and complex. Changes occurred in the whole crop and animal production, food processing and consumption chain, and were largest in the most populous areas between 1980 and 2005.

  1. Nitrogen Cycle Modeling: a Mechanistic Estimate of N-losses From Agricultural Fields Over the Seasonal Time Period

    NASA Astrophysics Data System (ADS)

    Maggi, F.; Gu, C.; Venterea, R.; Riley, W.; Oldenburg, C.

    2007-12-01

    The biogeochemical cycle of nitrogen and production of NO, N2O, and CO2 gas and NO2- and NO3- ions in nutrient-enriched agricultural fields is mediated by soil microbial activity, the hydrological cycle, plant dynamics, and climatic forcing. Understanding how NO, N2O, CO2 gases and NO2- and NO3- ions are released from agricultural fields to the environment is a key factor in controlling the green-house effect and water contamination, and assumes ever greater importance in view of the foreseen increase in biofuel, food, and fiber production. To address these issues we have developed a mechanistic model (TOUGHREACT-N) for various nitrification and denitrification pathways, multiple microbial biomass dynamics, heat and water flows, and various chemical reactions at local and kinetic equilibrium. The soil column is represented in a 1D framework, with hydraulic properties described by a water tension-saturation model. Biotic and abiotic reactions are assumed to follow Michaelis-Menten kinetics, while a consortium of several micro-organismal strains is assumed to follow multiple Monod growth kinetics accounting for electron donor, electron acceptor, and inhibitor concentrations. Water flow is modeled with the Darcy-Richards equation, while nutrient transport is modeled by Fickian advective and diffusive processes in both gaseous and liquid phases. Heat flow is modeled with the Fourier equation. Plant dynamics is taken into account by coupling TOUGHREACT-N with CERES to determine water and nutrient uptake, and soil carbon accumulation. TOUGHREACT-N was calibrated against field measurements to assess pathways of N losses following fertilization. A good agreement between field observations and model predictions was found. We identified two dominant time scales in the system response that depended on plants dynamics. Before plants have substantial impact on soil nutrients and moisture content, N losses are characterized by rapid increases as a function of water application

  2. Soil nitrogen gas fluxes during woody legume encroachment: Does encroachment increase gaseous losses?

    NASA Astrophysics Data System (ADS)

    Soper, F.; Groffman, P. M.; Sparks, J. P.

    2014-12-01

    Expansion of nitrogen (N2)-fixing trees is a major driver of ecosystem N enrichment in semi-arid grasslands. During this process, fluxes of N trace gases from soils are likely mediated by interactions between changing soil N availability and primary abiotic biogeochemical drivers in arid systems, namely temperature and wetting/re-wetting dynamics. We investigated the effects of encroachment, season and rainfall dynamics on total reactive N flux (NO, NOy, NH3, N2O) in a sub-tropical, semi-arid Texan savanna encroached by N-fixing Prosopis glandulosa over two years. We compared unencroached upland grasslands and non-fixing woody clusters with continuous Prosopis cover over uplands, intermediate drainages, and playa lowlands. We also quantified denitrification potential of intact soil cores to determine whether N2 could contribute significantly to soil N flux. Substantial soil N enrichment in upland Prosopis groves did not elevate N fluxes above those in remnant grasslands, though lower (moister) landscape positions did exhibit higher total emissions. Along with temperature, soil-wetting dynamics explained the greatest portion of variation in emissions and interacted with vegetation type. Timing and quantity of most recent soil wetting and interval to previous wetting were significant predictors, highlighting the importance of dynamics not captured by soil moisture measurements alone. As with other arid systems, rainfall events after dry periods can stimulate pulse emissions of >400 ug NO-N m-2 h-1. At realistic soil O2 concentrations, N2 fluxes fell below the detection limit of the Nitrogen-Free Atmospheric Recirculation Method system (~11 ug N m-2 h-1). However, applying plausible N2O:N2 flux ratios likely constrains the flux to much lower levels under field conditions. We conclude that encroachment does not increase N fluxes from upland savannas, but that interactions with rainfall and landscape position are important determinants of total emissions.

  3. Estimating Annual Soil Carbon Loss in Agricultural Peatland Soils Using a Nitrogen Budget Approach

    PubMed Central

    Kirk, Emilie R.; van Kessel, Chris; Horwath, William R.; Linquist, Bruce A.

    2015-01-01

    Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta) has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM) oxidation and physical compaction. Rice (Oryza sativa) production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 – 4 % combined). Shallow groundwater contributed 24 – 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 – 81 % of plant N uptake (129 – 149 kg N ha-1) was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 – 70 %, estimated net C loss ranged from 1149 – 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices. PMID:25822494

  4. Estimating annual soil carbon loss in agricultural peatland soils using a nitrogen budget approach.

    PubMed

    Kirk, Emilie R; van Kessel, Chris; Horwath, William R; Linquist, Bruce A

    2015-01-01

    Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta) has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM) oxidation and physical compaction. Rice (Oryza sativa) production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 - 4 % combined). Shallow groundwater contributed 24 - 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 - 81 % of plant N uptake (129 - 149 kg N ha-1) was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 - 70 %, estimated net C loss ranged from 1149 - 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices.

  5. Body protein losses estimated by nitrogen balance and potassium-40 counting

    SciTech Connect

    Belyea, R.L.; Babbitt, C.L.; Sedgwick, H.T.; Zinn, G.M.

    1986-07-01

    Body protein losses estimated from N balance were compared with those estimated by 40K counting. Six nonlactating dairy cows were fed an adequate N diet for 7 wk, a low N diet for 9 wk, and a replete N diet for 3 wk. The low N diet contained high cell wall grass hay plus ground corn, starch, and molasses. Soybean meal was added to the low N diet to increase N in the adequate N and replete N diets. Intake was measured daily. Digestibilities, N balance, and body composition (estimated by 40K counting) were determined during each dietary regimen. During low N treatment, hay dry matter intake declined 2 kg/d, and supplement increased about .5 kg/d. Dry matter digestibility was not altered by N treatment. Protein and acid detergent fiber digestibilities decreased from 40 and 36% during adequate N to 20 and 2%, respectively, during low N. Fecal and urinary N also declined when cows were fed the low N diet. By the end of repletion, total intake, fiber, and protein digestibilities as well as N partition were similar to or exceeded those during adequate N intake. Body protein (N) loss was estimated by N balance to be about 3 kg compared with 8 kg by 40K counting. Body fat losses (32 kg) were large because of low energy digestibility and intake. Seven kilograms of body fat were regained during repletion, but there was no change in body protein.

  6. The consequence of species loss on ecosystem nitrogen cycling depends on community compensation.

    PubMed

    Suding, Katharine Nash; Miller, Amy E; Bechtold, Heather; Bowman, William D

    2006-08-01

    Repercussions of species loss on ecosystem processes depend on the effects of the lost species as well as the compensatory responses of the remaining species in the community. We experimentally removed two co-dominant plant species and added a 15N tracer in alpine tundra to compare how species' functional differences influence community structure and N cycling. For both of the species, production compensated for the biomass removed by the second year. However, the responses of the remaining species depended on which species was removed. These differences in compensation influenced how species loss impacted ecosystem processes. After the removal of one of the co-dominant species, Acomastylis rossii, there were few changes in the relative abundance of the remaining species, and differences in functioning could be predicted based on effects associated with the removed species. In contrast, the removal of the other co-dominant, Deschampsia caespitosa, was associated with subsequent changes in community structure (species relative abundances and diversity) and impacts on ecosystem properties (microbial biomass N, dissolved organic N, and N uptake of subordinate species). Variation in compensation may contribute to the resulting effects on ecosystem functioning, with the potential to buffer or accelerate the effects of species loss.

  7. Relation between irrigation method, sediment yields, and losses of pesticides and nitrogen

    USGS Publications Warehouse

    Ebbert, J.C.; Kim, M.H.

    1998-01-01

    Yields of suspended sediment from watersheds in the Quincy and Pasco Basins of Washington State have been reduced by the use of sprinkler irrigation on cropland previously in furrow irrigation. Mean daily yields of suspended sediment from nine watersheds sampled during April and May 1994 ranged from 0.4 kg/ha of irrigated cropland in a watershed with no furrow irrigation to 19 kg/ha in a watershed where 58% of irritated cropland was in furrow irrigation. About 67% of the variation in the yields can be attributed to irrigation method. Temporal trends also indicated that use of sprinkler irrigation reduced sediment yields. Mean daily yields of suspended solids from one of the watersheds decreased from 0.3 kg/ha in 1975 to <0.2 kg/ha in 1988, corresponding with a decrease from about 65% to <50% in the use of furrow irrigation. Sampling in two watersheds suggests that the use of sprinkler irrigation reduces runoff losses of pesticides and N. For 10 of 13 pesticides and N, runoff losses from a watershed with mostly furrow irrigation exceeded runoff losses from a watershed with mostly sprinkler irrigation.

  8. Nitrate Leaching Index

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Nitrate Leaching Index is a rapid assessment tool that evaluates nitrate (NO3) leaching potential based on basic soil and climate information. It is the basis for many nutrient management planning efforts, but it has considerable limitations because of : 1) an oversimplification of the processes...

  9. Oak loss increases foliar nitrogen, δ(15)N and growth rates of Betula lenta in a northern temperate deciduous forest.

    PubMed

    Falxa-Raymond, Nancy; Patterson, Angelica E; Schuster, William S F; Griffin, Kevin L

    2012-09-01

    Oak forests dominate much of the eastern USA, but their future is uncertain due to a number of threats and widespread failure of oak regeneration. A sudden loss of oaks (Quercus spp.) could be accompanied by major changes in forest nitrogen (N) cycles with important implications for plant nutrient uptake and tree species composition. In this study, we measured the changes in N use and growth rates of black birch trees (Betula lenta L.) following oak girdling at the Black Rock Forest in southeastern New York, USA. Data were collected from nine experimental plots composed of three treatments: 100% oaks girdled (OG), 50% oaks girdled (O50) and control (C). Foliar N concentration and foliar (15)N abundance increased significantly in the oak-girdled plots relative to the control, indicating that the loss of oaks significantly altered N cycling dynamics. As mineralization and nitrification rates increase following oak loss, black birch trees increase N absorption as indicated by higher foliar N content and increased growth rates. Foliar N concentration increased by 15.5% in the O50 and 30.6% in the OG plots relative to the control, while O50 and OG plots were enriched in (15)N by 1.08‰ and 3.33‰, respectively (P < 0.0001). A 641% increase in black birch growth rates in OG plots suggests that this species is able to respond to additional N availability and/or increased light availability. The loss of oaks and subsequent increase in black birch productivity may have a lasting impact on ecosystem form and function.

  10. High N, dry: Experimental nitrogen deposition exacerbates native shrub loss and nonnative plant invasion during extreme drought.

    PubMed

    Valliere, Justin M; Irvine, Irina C; Santiago, Louis; Allen, Edith B

    2017-03-20

    Hotter, longer, and more frequent global change-type drought events may profoundly impact terrestrial ecosystems by triggering widespread vegetation mortality. However, severe drought is only one component of global change, and ecological effects of drought may be compounded by other drivers, such as anthropogenic nitrogen (N) deposition and nonnative plant invasion. Elevated N deposition, for example, may reduce drought tolerance through increased plant productivity, thereby contributing to drought-induced mortality. High N availability also often favors invasive, nonnative plant species, and the loss of woody vegetation due to drought may create a window of opportunity for these invaders. We investigated the effects of multiple levels of simulated N deposition on a Mediterranean-type shrubland plant community in southern California from 2011 to 2016, a period coinciding with an extreme, multi-year drought in the region. We hypothesized that N addition would increase native shrub productivity, but that this would increase susceptibility to drought and result in increased shrub loss over time. We also predicted that N addition would favor nonnatives, especially annual grasses, leading to higher biomass and cover of these species. Consistent with these hypotheses, we found that high N availability increased native shrub canopy loss and mortality, likely due to the higher productivity and leaf area and reduced water-use efficiency we observed in shrubs subject to N addition. As native shrub cover declined, we also observed a concomitant increase in cover and biomass of nonnative annuals, particularly under high levels of experimental N deposition. Together, these results suggest that the impacts of extended drought on shrubland ecosystems may be more severe under elevated N deposition, potentially contributing to the widespread loss of native woody species and vegetation type-conversion. This article is protected by copyright. All rights reserved.

  11. Impacts of management and climate change on nitrate leaching in a forested karst area.

    PubMed

    Thomas, Dirnböck; Johannes, Kobler; David, Kraus; Rüdiger, Grote; Ralf, Kiese

    2016-01-01

    Forest management and climate change, directly or indirectly, affect drinking water resources, both in terms of quality and quantity. In this study in the Northern Limestone Alps in Austria we have chosen model calculations (LandscapeDNDC) in order to resolve the complex long-term interactions of management and climate change and their effect on nitrogen dynamics, and the consequences for nitrate leaching from forest soils into the karst groundwater. Our study highlights the dominant role of forest management in controlling nitrate leaching. Both clear-cut and shelterwood-cut disrupt the nitrogen cycle to an extent that causes peak concentrations and high fluxes into the seepage water. While this effect is well known, our modelling approach has revealed additional positive as well as negative impacts of the expected climatic changes on nitrate leaching. First, we show that peak nitrate concentrations during post-cutting periods were elevated under all climate scenarios. The maximal effects of climatic changes on nitrate concentration peaks were 20-24 mg L(-1) in 2090 with shelterwood or clear-cut management. Second, climate change significantly decreased the cumulative nitrate losses over full forest rotation periods (by 10-20%). The stronger the expected temperature increase and precipitation decrease (in summer), the lesser were the observed nitrate losses. However, mean annual seepage water nitrate concentrations and cumulative nitrate leaching were higher under continuous forest cover management than with shelterwood-cut and clear-cut systems. Watershed management can thus be adapted to climate change by either reducing peak concentrations or long-term loads of nitrate in the karst groundwater.

  12. Ammonia losses and nitrogen partitioning at a southern High Plains open lot dairy

    NASA Astrophysics Data System (ADS)

    Todd, Richard W.; Cole, N. Andy; Hagevoort, G. Robert; Casey, Kenneth D.; Auvermann, Brent W.

    2015-06-01

    Animal agriculture is a significant source of ammonia (NH3). Cattle excrete most ingested nitrogen (N); most urinary N is converted to NH3, volatilized and lost to the atmosphere. Open lot dairies on the southern High Plains are a growing industry and face environmental challenges as well as reporting requirements for NH3 emissions. We quantified NH3 emissions from the open lot and wastewater lagoons of a commercial New Mexico dairy during a nine-day summer campaign. The 3500-cow dairy consisted of open lot, manure-surfaced corrals (22.5 ha area). Lactating cows comprised 80% of the herd. A flush system using recycled wastewater intermittently removed manure from feeding alleys to three lagoons (1.8 ha area). Open path lasers measured atmospheric NH3 concentration, sonic anemometers characterized turbulence, and inverse dispersion analysis was used to quantify emissions. Ammonia fluxes (15-min) averaged 56 and 37 μg m-2 s-1 at the open lot and lagoons, respectively. Ammonia emission rate averaged 1061 kg d-1 at the open lot and 59 kg d-1 at the lagoons; 95% of NH3 was emitted from the open lot. The per capita emission rate of NH3 was 304 g cow-1 d-1 from the open lot (41% of N intake) and 17 g cow-1 d-1 from lagoons (2% of N intake). Daily N input at the dairy was 2139 kg d-1, with 43, 36, 19 and 2% of the N partitioned to NH3 emission, manure/lagoons, milk, and cows, respectively.

  13. Effect of turning regime and seasonal weather conditions on nitrogen and phosphorus losses during aerobic composting of cattle manure.

    PubMed

    Parkinson, R; Gibbs, P; Burchett, S; Misselbrook, T

    2004-01-01

    Cattle manure from stock bedded on straw was aerobically composted under ambient conditions, turning with either a tractor-mounted front-end loader or a rear discharge manure spreader. Three composting experiments, each of approximately four months duration, were conducted to investigate the effect of turning regime and seasonal weather conditions on nitrogen and phosphorus losses during aerobic composting of cattle manure. Manure stacks of 12-15 m(3) initial volume were constructed in separate 5 x 5 m concrete compartments. Experiment 1 (January-April 1999) compared manure heaps turned once (T1) or three times (T3) using a front-end loader with an unturned static (S) control manure stack. Experiment 2 (June-September 1999) compared the same treatments as Experiment 1. Experiment 3 (September-December 1999) compared T1 and T3 turning regimes using a front end loader with turning by a rear-discharge spreader (TR1 and TR1T2) for more effective aeration of the manure. Turning took place at 6 weeks for the one turn treatments, and after 2, 6 and 10 weeks for the three turn treatments. Leachate losses were dominated by NH(4)-N during the first three weeks of composting, after which time NH4-N and NO3-N concentrations in leachates were approximately the same, in the range 0-20 mg N l(-1). The concentrations of both NH4-N and NO3-N in leachate were higher after turning. Molybdate-reactive P concentrations in leachate tended not to be significantly influenced by turning regime. Gaseous losses of NH3 and N2O rose quickly during the initial phases of composting, peaking at 152 g N t(-1) d(-1) for the T3 treatment. Mean NH3 emission rate (25-252 g N t(-1) d(-1)) for the first two weeks of Experiment 2 conducted during the period June-September were an order of magnitude greater (1-10 g N t(-1) d(-1)) than Experiment 3, conducted during the colder, wetter autumn period (September-December). Nitrous oxide emission rates ranged between 1-14 g N t(-1) d(-1) and showed little

  14. Effect of dietary concentrate on rumen fermentation, digestibility, and nitrogen losses in dairy cows.

    PubMed

    Agle, M; Hristov, A N; Zaman, S; Schneider, C; Ndegwa, P M; Vaddella, V K

    2010-09-01

    The objective of this experiment was to investigate the effect of level of dietary concentrate on rumen fermentation, digestibility, and N losses in lactating dairy cows. The experiment was a replicated 3x3 Latin square design with 6 cows and 16-d adaptation periods. Ruminal contents were exchanged between cows at the beginning of each adaptation period. Data for 2 of the diets tested in this experiment are presented here. The diets contained (dry matter basis): 52% (LowC; control) and 72% (HighC) concentrate feeds. Crude protein contents of the diets were 16.5 and 16.4%, respectively. The HighC diet decreased ruminal pH and ammonia concentration and increased propionate concentration compared with LowC. Acetate:propionate ratio was greater for LowC than for HighC. Rumen methane production and microbial protein synthesis were unaffected by diet. Dry matter intake was similar among diets, but milk yield was increased by HighC compared with LowC (36.0 and 33.2 kg/d, respectively). Milk fat percentage and yield and total-tract apparent NDF digestibility were decreased by HighC compared with LowC. More ruminal ammonia N was transferred into milk protein with HighC than with LowC. Urinary N excretion, plasma urea N, and milk urea N concentration were not affected by diet. The ammonia emitting potential of manure was similar between LowC and HighC diets. Increased concentrate proportion in the diet of dairy cows resulted in reduced ruminal ammonia concentration and enhanced ammonia utilization for milk protein synthesis. These effects, however, did not result in reduced urinary N losses and only marginally improved milk N efficiency. Increasing dietary concentrate was not a successful strategy to mitigate enteric methane production and ammonia emissions from manure.

  15. Role of biochar amendment in mitigation of nitrogen loss and greenhouse gas emission during sewage sludge composting.

    PubMed

    Awasthi, Mukesh Kumar; Wang, Quan; Ren, Xiuna; Zhao, Junchao; Huang, Hui; Awasthi, Sanjeev Kumar; Lahori, Altaf Hussain; Li, Ronghua; Zhou, Lina; Zhang, Zengqiang

    2016-11-01

    The objective of the present study was to mitigate the greenhouse gas (GHG) emissions during composting of dewatered fresh sewage sludge (DFSS) employing biochar combined with zeolite (B+Z) and low dosage of lime (B+L). The 12% biochar was mixed at a 10%, 15% and 30% of zeolite and 1% lime, while without any additives was used as control. The results indicated that the combine use of B+Z was significantly increased the enzymatic activities and reduced the ammonia loss 58.03-65.17% as compare to B+L amended treatment, while CH4 92.85-95.34% and N2O 95.14-97.28% decreased than control. The B+L1% amendment significantly increased the organic matter degradation but the reduction was lower than B+Z and that could reduce the CH4 and N2O emission by 55.17-63.08% and 62.24-65.53% as compare to control, respectively. Overall our results demonstrated that 12%B+Z10% addition into DFSS can be potentially used to improve the DFSS composting by mitigation of GHG emission and nitrogen loss.

  16. Subalpine grassland carbon dioxide fluxes indicate substantial carbon losses under increased nitrogen deposition, but not at elevated ozone concentration

    NASA Astrophysics Data System (ADS)

    Volk, Matthias; Obrist, Daniel; Novak, Kris; Giger, Robin; Bassin, Seraina; Fuhrer, Jürg

    2010-05-01

    Ozone (O3) and nitrogen (N) deposition affect plant carbon (C) dynamics and may thus change ecosystem C-sink/-source properties. We studied effects of increased background O3 concentrations (up to ambient x 2) and increased N deposition (up to +50 kg ha-1 a-1) on mature, subalpine grassland during the third treatment year. During ten days and 13 nights, covering the vegetation period of 2006, we measured ecosystem-level CO2 exchange using a steady state cuvette. Light dependency of gross primary production (GPP) and temperature dependency of ecosystem respiration rates (Reco) were established. Soil temperature, soil water content, and solar radiation were monitored. Using Reco and GPP values, we calculated seasonal net ecosystem production (NEP), based on hourly averages of global radiation and soil temperature. Differences in NEP were compared to differences in soil organic C after five years of treatment. Under high O3 and with unchanged aboveground biomass, both mean Reco and GPP decreased throughout the season. Thus, NEP indicated an unaltered growing season CO2-C balance. Under high N treatment, with a +31% increase in aboveground productivity, mean Reco, but not GPP increased. Consequently, seasonal NEP yielded a 53.9 g C m-2 (± 22.05) C loss compared to control. Independent of treatment, we observed a negative NEP of 146.4 g C m-2 (±15.3). This C loss was likely due to a transient management effect, equivalent to a shift from pasture to hay meadow and a drought effect, specific to the 2006 summer climate. We argue that this resulted from strongly intensified soil microbial respiration, following mitigation of nutrient limitation. There was no interaction between O3 and N treatments. Thus, during the 2006 growing season, the subalpine grassland lost >2% of total topsoil organic C as respired CO2, with increased N deposition responsible for one-third of that loss.

  17. Assessment of nitrogen losses through nitrous oxide from abattoir wastewater-irrigated soils.

    PubMed

    Matheyarasu, Raghupathi; Seshadri, Balaji; Bolan, Nanthi S; Naidu, Ravi

    2016-11-01

    The land disposal of waste and wastewater is a major source of N2O emission. This is due to the presence of high concentrations of nitrogen (N) and carbon in the waste. Abattoir wastewater contains 186 mg/L of N and 30.4 mg/L of P. The equivalent of 3 kg of abattoir wastewater-irrigated soil was sieved and taken in a 4-L plastic container. Abattoir wastewater was used for irrigating the plants at the rates of 50 and 100 % field capacity (FC). Four crop species were used with no crop serving as a control. Nitrous oxide emission was monitored using a closed chamber technique. The chamber was placed inside the plastic container, and N2O emission was measured for 7 days after the planting. A syringe and pre-evacuated vial were used for collecting the gas samples; a fresh and clean syringe was used each time to avoid cross-contamination. The collected gas samples were injected into a gas chromatography device immediately after each sampling to analyse the concentration of N2O from different treatments. The overall N2O emission was compared for all the crops under two different abattoir wastewater treatment rates (50 and 100 % FC). Under 100 % FC (wastewater irrigation), among the four species grown in the abattoir wastewater-irrigated soil, Medicago sativa (23 mg/pot), Sinapis alba (21 mg/pot), Zea mays (20 mg/pot) and Helianthus annuus (20 mg/pot) showed higher N2O emission compared to the 50 % treatments-M. sativa (17 mg/pot), S. alba (17 mg/pot), Z. mays (18 mg/pot) and H. annuus (18 mg/pot). Similarly, pots with plants have shown 15 % less emission than the pots without plants. Similar trends of N2O emission flux were observed between the irrigation period (4-week period) for 50 % FC and 100 % FC. Under the 100 % FC loading rate treatments, the highest N2O emission was in the following order: week 1 > week 4 > week 3 > week 2. On the other hand, under the 50 % FC loading rate treatments, the highest N2O emission was recorded in the first

  18. [Fate and balance of bulk blending controlled release fertilizer nitrogen under continuous cropping of mustard].

    PubMed

    Zhang, Pan-Pan; Fan, Xiao-Lin

    2012-10-01

    Under the conditions of applying water soluble fertilizer and its bulk blending with controlled release fertilizer (BB-CRF), and by using micro-lysimeter, this paper quantitatively studied the nitrogen (N) uptake by mustard, the soil N losses from N2O emission, leaching and others, and the N residual in soil in three rotations of continuously cropped mustard. In the treatment of BB-CRF with 25% of controlled release nitrogen, the N uptake by mustard increased with rotations, and the yield by the end of the experiment was significantly higher than that in the treatment of water soluble fertilizer. The cumulated N2O emission loss and the N leaching loss were obviously higher in treatment water soluble fertilizer than in treatment BB-CRF. NO3(-)-N was the primary form of N in the leachate. In relative to water soluble fertilizer, BB-CRF altered the fates of fertilizer nitrogen, i.e., the N uptake by mustard and the N residual in soil increased by 75.4% and 76.0%, and the N leaching loss and other apparent N losses decreased by 27.1% and 66.3%, respectively. The application of BB-CRF could be an effective way to reduce the various losses of fertilizer N while increase the fertilizer N use efficiency, and the controlled release fertilizer is the environmentally friendly fertilizer with the property of high N use efficiency.

  19. Ammonium loss and nitrogen isotopic fractionation in biotite as a function of metamorphic grade in metapelites from western Maine, USA

    NASA Astrophysics Data System (ADS)

    Plessen, Birgit; Harlov, Daniel E.; Henry, Darrell; Guidotti, Charles V.

    2010-08-01

    Ammonium fixed in micas of metamorphic rocks is a sensitive indicator both of organic-inorganic interactions during diagenesis as well as of the devolatilization history and fluid/rock interaction during metamorphism. In this study, a collection of geochemically well-characterized biotite separates from a series of graphite-bearing Paleozoic greenschist- to upper amphibolite-facies metapelites, western Maine, USA, were analyzed for ammonium nitrogen ( NH4+-N) contents and isotopic composition (δ 15N NH4) using the HF-digestion distillation technique followed by the EA-IRMS technique. Biotite separates, sampled from 9 individual metamorphic zones, contain 3000 to 100 ppm NH4+-N with a wide range in δ 15N from +1.6‰ to +9.1‰. Average NH4+-N contents in biotite show a distinct decrease from about 2750 ppm for the lowest metamorphic grade (˜500 °C) down to 218 ppm for the highest metamorphic grade (˜685 °C). Decreasing abundances in NH4+ are inversely correlated in a linear fashion with increasing K + in biotite as a function of metamorphic grade and are interpreted as a devolatilization effect. Despite expected increasing δ 15N NH4 values in biotite with nitrogen loss, a significant decrease from the Garnet Zones to the Staurolite Zones was found, followed by an increase to the Sillimanite Zones. This pattern for δ 15N NH4 values in biotite inversely correlates with Mg/(Mg + Fe) ratios in biotite and is discussed in the framework of isotopic fractionation due to different exchange processes between NH4+-NH or NH4+-N, reflecting devolatilization history and redox conditions during metamorphism.

  20. Leaching of DOC, DN, and inorganic constituents from scrap tires.

    PubMed

    Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

    2015-11-01

    One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse.

  1. MASS LOSS AND NITROGEN DYNAMICS DURING THE DECOMPOSITION OF A N-LABELED N2-FIXING EPOPHYTIC LICHEN, LOBARIA OREGANA (TUCK.) MULL. ARG.

    EPA Science Inventory

    We studied mass loss and nitrogen dynamics during fall and spring initiated decomposition of an N2-fixing epiphytic lichen, Lobaria oregana (Tuck.) Mull. Arg. using 15N. We developed a method of labeling lichens with 15N that involved spraying lichen material with a nutrient sol...

  2. Losses in carbon and nitrogen stocks in soil particle-size fractions along cultivation chronosequences in Inner Mongolian grasslands.

    PubMed

    He, Nianpeng; Zhang, Yunhai; Dai, Jingzhong; Han, Xingguo; Yu, Guirui

    2012-01-01

    Cultivation in semiarid grasslands induces large changes in soil organic matter (SOM) stock. To better predict the effects of cultivation on SOM pools, there is a need to identify the soil fractions that are affected and the extent to which they are affected. Using four cultivation chronosequences in Inner Mongolian grasslands of northern China, we investigated the changes in soil organic carbon (SOC) and total nitrogen (N) stocks in soil particle-size fractions to identify the effect of cultivation on SOM dynamics. The results showed that conversion of native grasslands into croplands significantly decreased the SOC stocks (4.34-31.65 Mg C ha) and N (0.19-2.54 Mg N ha) in the 0- to 100-cm layer after cultivation. Prominent changes were observed in the SOC and N stocks in the 0- to 10-cm layer and were, on average, 6.56 Mg C ha (24.85%) and 0.63 Mg N ha (23.48%), respectively. The effect of cultivation on the SOC and N stocks in soil fractions was in the order sand > silt > clay. The C and N stocks in the 0- to 10-cm soil layer in the sand fraction in croplands decreased, on average, by 4.74 Mg C ha (35.86%) and 0.48 Mg N ha (41.30%), respectively, compared with those in native grasslands. The declines in the silt and clay fractions were small. Thus, sand fraction was a more important contributor to C and N losses in soil after cultivation than silt or clay fraction. Our findings indicate that the preliminary responses of SOC and N to cultivation in a semiarid grassland area and have significant implications for assessing the loss or gain of C and N during grassland conversion.

  3. Nitrogen Losses as N2O and NO After Non-tillage Agricultural Practice in a Tropical Corn Field at Guarico State, Venezuela.

    NASA Astrophysics Data System (ADS)

    Perez, T. J.; Gil, J. A.; Marquina, S.; Donoso, L. E.; Trumbore, S. E.; Tyler, S. C.

    2005-12-01

    Historically, the most common agricultural practice in Northern Guárico, one of Venezuelan largest cereal production regions, has been mono cropping, with extensive tillage operations that usually causes rapid soil degradation and nitrogen losses. Alternative production systems, such as non-tillage agricultural practices, have been extensively implemented during the last few years. However, studies of the nitrogen losses associated with these alternative practices are not widely available. This study was conducted at "Fundo Tierra Nueva", Guárico State (9°23'33" N, 66° 38'30" W) in a corn field under the non-tillage agricultural practice, during the growing season June-August 2005. The soils are Vertisols (Typic Haplusterts). The area has two well defined precipitation seasons: wet (May-October) and dry (November-April). The mean annual precipitation of the area is 622±97.3 mm (last 5 years). Because the irrigation of the crop depends on precipitation, the planting is scheduled during the months of highest precipitation in June-July. We measured nitrogenous gas emissions (N2O and NO), concentrations of total nitrogen (NT), NH4+ and NO3- in soil (0-100 cm) after fertilization to estimate the nitrogen losses. We also measured CO2 emissions to evaluate the relationship of microbial respiration to the emissions of nitrogenous trace gases. Soils were fertilized with 54 kgN/ha (NPK 12:24:12, nitrogen as NH4Cl) and planted simultaneously by a planting machine provided with a furrow opener where the fertilizer and seeds are incorporated between 0-10 cm depth. Thirty days later, soils were fertilized by broadcast addition of 18 kgN/ha (as ammonium nitrate). Nitrous oxide emissions were highly dependant on the water content. Prior to fertilization N2O emissions were very low. Right after fertilization the emissions increased by a factor of 5 compared to pre-fertilization levels and increased to 100 times larger after the first heavy rain. NO emissions did not increase

  4. No-tillage and fertilization management on crop yields and nitrate leaching in North China Plain

    PubMed Central

    Huang, Manxiang; Liang, Tao; Wang, Lingqing; Zhou, Chenghu

    2015-01-01

    A field experiment was performed from 2003 to 2008 to evaluate the effects of tillage system and nitrogen management regimes on crop yields and nitrate leaching from the fluvo-aquic soil with a winter wheat (Triticum aestivum L.)–maize (Zea mays L.) double-cropping system. The tillage systems consisted of conventional tillage (CT) and no-tillage (NT). Three nitrogen management regimes were included: 270 kg N ha−1 of urea for wheat and 225 kg N ha−1 of urea for maize (U), 180 kg N ha−1 of urea and 90 kg N ha−1 of straw for wheat and 180 kg N of urea and 45 kg N ha−1 of straw for maize (S), 180 kg N ha−1 of urea and 90 kg N ha−1 of manure for wheat and 180 kg N ha−1 of urea and 45 kg N ha−1 of manure for maize (M). An array of tension-free pan lysimeters (50 cm × 75 cm) were installed (1.2 m deep) to measure water flow and -N movement. No significant effect of the N management regime on yields of winter wheat and maize grain was found in the 5-year rotation. Tillage systems had significant influences on -N leaching from the second year and thereafter interacted with N management regimes on -N loads during all maize seasons. The average yield-scaled -N leaching losses were in order of CTS < NTS< CTU < NTU leaching losses while sustaining crop grain yields. Considering the lower costs, NTS could be a potential alternative to decrease yield-scaled -N leaching losses and improve soil fertility while maintaining crop yield for the winter wheat–maize double-cropping systems in the North China Plain. PMID:25859321

  5. No-tillage and fertilization management on crop yields and nitrate leaching in North China Plain.

    PubMed

    Huang, Manxiang; Liang, Tao; Wang, Lingqing; Zhou, Chenghu

    2015-03-01

    A field experiment was performed from 2003 to 2008 to evaluate the effects of tillage system and nitrogen management regimes on crop yields and nitrate leaching from the fluvo-aquic soil with a winter wheat (Triticum aestivum L.)-maize (Zea mays L.) double-cropping system. The tillage systems consisted of conventional tillage (CT) and no-tillage (NT). Three nitrogen management regimes were included: 270 kg N ha(-1) of urea for wheat and 225 kg N ha(-1) of urea for maize (U), 180 kg N ha(-1) of urea and 90 kg N ha(-1) of straw for wheat and 180 kg N of urea and 45 kg N ha(-1) of straw for maize (S), 180 kg N ha(-1) of urea and 90 kg N ha(-1) of manure for wheat and 180 kg N ha(-1) of urea and 45 kg N ha(-1) of manure for maize (M). An array of tension-free pan lysimeters (50 cm × 75 cm) were installed (1.2 m deep) to measure water flow and [Formula: see text]-N movement. No significant effect of the N management regime on yields of winter wheat and maize grain was found in the 5-year rotation. Tillage systems had significant influences on [Formula: see text]-N leaching from the second year and thereafter interacted with N management regimes on [Formula: see text]-N loads during all maize seasons. The average yield-scaled [Formula: see text]-N leaching losses were in order of CTS < NTS< CTU < NTU leaching losses while sustaining crop grain yields. Considering the lower costs, NTS could be a potential alternative to decrease yield-scaled [Formula: see text]-N leaching losses and improve soil fertility while maintaining crop yield for the winter wheat-maize double-cropping systems in the North China Plain.

  6. High-Resolution Electron Energy Loss Studies of Oxygen, Hydrogen, Nitrogen, Nitric Oxide, and Nitrous Oxide Adsorption on Germanium Surfaces.

    NASA Astrophysics Data System (ADS)

    Entringer, Anthony G.

    The first high resolution electron energy loss spectroscopy (HREELS) studies of the oxidation and nitridation of germanium surfaces are reported. Both single crystal Ge(111) and disordered surfaces were studied. Surfaces were exposed to H, O_2, NO, N _2O, and N, after cleaning in ultra-high vacuum. The Ge surfaces were found to be non-reactive to molecular hydrogen (H_2) at room temperature. Exposure to atomic hydrogen (H) resulted hydrogen adsorption as demonstrated by the presence of Ge-H vibrational modes. The HREEL spectrum of the native oxide of Ge characteristic of nu -GeO_2 was obtained by heating the oxide to 200^circC. Three peaks were observed at 33, 62, and 106 meV for molecular oxygen (O_2) adsorbed on clean Ge(111) at room temperature. These peaks are indicative of dissociative bonding and a dominant Ge-O-Ge bridge structure. Subsequent hydrogen exposure resulted in a shift of the Ge-H stretch from its isolated value of 247 meV to 267 meV, indicative of a dominant +3 oxidation state. A high density of dangling bonds and defects and deeper oxygen penetration at the amorphous Ge surface result in a dilute bridge structure with a predominant +1 oxidation state for similar exposures. Molecules of N_2O decompose at the surfaces to desorbed N_2 molecules and chemisorbed oxygen atoms. In contrast, both oxygen and nitrogen are detected at the surfaces following exposure to NO molecules. Both NO and N_2O appear to dissociate and bond at the top surface layer. Molecular nitrogen (N_2) does not react with the Ge surfaces, however, a precursor Ge nitride is observed at room temperature following exposure to nitrogen atoms and ions. Removal of oxygen by heating of the NO-exposed surface to 550^circC enabled the identification of the Ge-N vibrational modes. These modes show a structure similar to that of germanium nitride. This spectrum is also identical to that of the N-exposed surface heated to 550^circC. Surface phonon modes of the narrow-gap semiconducting

  7. Spatial and temporal variations in non-point source losses of nitrogen and phosphorus in a small agricultural catchment in the Three Gorges Region.

    PubMed

    Chen, Chenglong; Gao, Ming; Xie, Deti; Ni, Jiupai

    2016-04-01

    Losses of agricultural pollutants from small catchments are a major issue for water quality in the Three Gorges Region. Solutions are urgently needed. However, before pollutant losses can be controlled, information about spatial and temporal variations in pollutant losses is needed. The study was carried out in the Wangjiagou catchment, a small agricultural catchment in Fuling District, Chongqing, and the data about non-point source losses of nitrogen and phosphorus was collected here. Water samples were collected daily by an automatic water sampler at the outlets of two subcatchments from 2012 to 2014. Also, samples of surface runoff from 28 sampling sites distributed through the subcatchments were collected during 12 rainfall events in 2014. A range of water quality variables were analyzed for all samples and were used to demonstrate the variation in non-point losses of nitrogen and phosphorus over a range of temporal and spatial scales and in different types of rainfall in the catchment. Results showed that there was a significant linear correlation between the mass concentrations of total nitrogen (TN) and nitrate (NO3-N) in surface runoff and that the relationship was maintained with changes in time. Concentrations of TN and NO3-N peaked after fertilizer was applied to crops in spring and autumn; concentrations decreased rapidly after the peak values in spring but declined slowly in autumn. N and P concentrations fluctuated more and showed a greater degree of dispersion during the spring crop cultivation period than those in autumn. Concentrations of TN and NO3-N in surface runoff were significantly and positively correlated with the proportion of the area that was planted with corn and mustard tubers, but were negatively correlated with the proportion of the area taken up with rice and mulberry plantations. The average concentrations of TN and NO3-N in surface runoff reached the highest level from the sampling points at the bottom of the land used for corn

  8. Short-term nitrogen losses by overland flow in a recently burnt forest area in north-central Portugal: A study at micro-plot scale.

    PubMed

    Ferreira, R V; Serpa, D; Machado, A I; Rodríguez-Blanco, M L; Santos, L F; Taboada-Castro, M T; Cerqueira, M A; Keizer, J J

    2016-12-01

    Over the past decades, wildfires have affected extensive areas of the Mediterranean region with negative impacts on the environment. Most of the studies on fire-affected areas have focused on sediment losses by overland flow, whereas few have addressed post-fire nutrient export. The present study aimed to address this research gap by assessing nitrogen (nitrate and total nitrogen) losses by overland flow in a recently burnt area in north-central Portugal. To this end, three burnt slopes were selected for their contrasting forest types (eucalypt vs. pine) and parent materials (granite vs. schist). The selected study sites were a eucalypt site on granite (BEG), a eucalypt site on schist (BES) and a maritime pine site on schist (BPS). Overland flow samples were collected during the first six months after the wildfire on a 1- to 2-weekly basis, after which this study had to be cancelled due to bench terracing of some of the sites. A peak in total nitrogen concentrations was observed in burnt areas immediately after the first post-fire rainfall event as a response to the erosion of the N-enriched ash layer. After this initial peak, smaller peaks were observed throughout the study period, mainly as a response to overland flow and/or erosion events. Nitrogen export differed strikingly between the two types of forests on schist, being higher at the eucalypt than at the pine site, due to the lack of a protective soil layer. Parent material did not play an important role on nitrogen export by overland flow since no significant differences were found between the eucalypt sites on granite and schist. The present study provides some insight into the differences in post-fire soil fertility losses between forest types and parent materials in the Mediterranean region, which is crucial information for defining post-fire land management measures to reduce soil degradation.

  9. IBIS Yield and Nitrate Loss Predictions for Maize Agroecosystems Receiving Varied N-Fertilizer

    NASA Astrophysics Data System (ADS)

    Kucharik, C. J.; Brye, K. R.

    2001-12-01

    Agriculture in the Midwest US faces the formidable challenge of improving crop productivity, while simultaneously mitigating the environmental consequences of intense management. This study examined the simultaneous response of nitrate-nitrogen (NO3-N) leaching losses and maize (Zea mays L.) yield to varied fertilizer-N management using field observations and the IBIS model. The model was validated against 6 yr of field observations in maize plots receiving an optimal (180 kg N/ha) fertilizer-N application and in N-unfertilized plots on a silt loam soil near Arlington, Wisconsin. Predicted values of grain yield, harvest index, plant N uptake, residue C:N ratio, LAI, grain-N, and drainage were within 20% of observations. However, simulated NO3-N leaching losses, NO3-N concentrations, and net N-mineralization exhibited less interannual variability than observations, and had higher levels of error (20-65%). Potential impacts of 30% higher (234 kg N/ha) and 30% lower (126 kg N/ha) fertilizer-N use (from optimal) on NO3-N leaching loss and maize yield were simulated. A 30% increase in fertilizer-N use increased annual NO3-N leaching by 56%, while yield increased by only 1%. The NO3-N concentration in the leachate solution at 1.4 m below the soil surface was 30.7 mg/L. When fertilizer-N use was reduced by 30% (from optimal), annual NO3-N leaching losses declined by 42% after 7 years, and annual average yield only decreased by 8%. However, NO3-N concentration in the leachate solution remained above 10 mg/L (11.3 mg/L). Clearly, non-linear relationships existed between changes in fertilizer use and NO3-N leaching losses over time. Simulated changes in NO3-N leaching were greater in magnitude than fertilizer-N use changes.

  10. Calibration and Validation of the Precision Nitrogen Management Tool for Artificially Drained Fields Under Maize

    NASA Astrophysics Data System (ADS)

    Marjerison, R.; Hutson, J.; Melkonian, J.; van Es, H.; Sela, S.

    2015-12-01

    Organic and inorganic fertilizer additions to agricultural fields can lead to soil nitrogen (N) levels in excess of those required for optimal crop growth. The primary loss pathways for this excess N are leaching and denitrification. Nitrate leaching from agricultural sources contributes to the formation of hypoxic zones in critical estuarine systems including the Chesapeake Bay and Gulf of Mexico. Denitrification can lead to the production of nitrous oxide (N2O), a potent greenhouse gas. Agricultural practices such as controlling the timing and location of fertilizer application can help reduce these losses. The Precision Nitrogen Management (PNM) model was developed to simulate water transport, nitrogen transformations and transport, and crop growth and nutrient uptake from agricultural fields. The PNM model allows for the prediction of N losses under a variety of crop and management scenarios. Recent improvements to the model include the option to simulate artificially drained fields. The model performs well in simulating drainage and nitrate leaching when compared to measured data from field studies in artificially drained soils in New York and Minnesota. A simulated N budget was compared to available data. The improved model will be used to assess different management options for reducing N losses in maize production under different climate projections for key maize production locations/systems in the U.S.

  11. Influences of biochar addition on vegetable soil nitrogen balance and pH buffering capacity

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Odindo, AO; Xue, L.; Yang, L.

    2016-08-01

    Leaching is a major path for chemical nitrogen fertilizer loss from in vegetable soil, which would destroy soil pH buffering capacity soil and result in acidification. It has been a common phenomenon in Tai Lake Region, China. However, few study focused on the change soil pH buffering capacity, especially the effect of soil amendment on pH buffering capacity. In this study, a pot experiment was conducted to research the effects of biochar addition to a vegetable soil on nitrogen leaching and pH buffering capacity with pakchoi (B.chinensis L.) growth as the experimental crop. The results showed that biochar could significantly increase the pakchoi nitrogen utilization efficiency, decrease 48%-65% nitrogen loss from leaching under the urea continuous applied condition. Biochar also could effectively maintain the content of soil organic matter and base cations. Therefore, it rose up soil pH buffering capacity by 9.4%-36.8% and significantly slowed down acidification rate. It was suggested that 1%-2% addition ratio was recommended from this study when used as similar soil condition.

  12. Application of modified export coefficient method on the load estimation of non-point source nitrogen and phosphorus pollution of soil and water loss in semiarid regions.

    PubMed

    Wu, Lei; Gao, Jian-en; Ma, Xiao-yi; Li, Dan

    2015-07-01

    Chinese Loess Plateau is considered as one of the most serious soil loss regions in the world, its annual sediment output accounts for 90 % of the total sediment loads of the Yellow River, and most of the Loess Plateau has a very typical characteristic of "soil and water flow together", and water flow in this area performs with a high sand content. Serious soil loss results in nitrogen and phosphorus loss of soil. Special processes of water and soil in the Loess Plateau lead to the loss mechanisms of water, sediment, nitrogen, and phosphorus are different from each other, which are greatly different from other areas of China. In this study, the modified export coefficient method considering the rainfall erosivity factor was proposed to simulate and evaluate non-point source (NPS) nitrogen and phosphorus loss load caused by soil and water loss in the Yanhe River basin of the hilly and gully area, Loess Plateau. The results indicate that (1) compared with the traditional export coefficient method, annual differences of NPS total nitrogen (TN) and total phosphorus (TP) load after considering the rainfall erosivity factor are obvious; it is more in line with the general law of NPS pollution formation in a watershed, and it can reflect the annual variability of NPS pollution more accurately. (2) Under the traditional and modified conditions, annual changes of NPS TN and TP load in four counties (districts) took on the similar trends from 1999 to 2008; the load emission intensity not only is closely related to rainfall intensity but also to the regional distribution of land use and other pollution sources. (3) The output structure, source composition, and contribution rate of NPS pollution load under the modified method are basically the same with the traditional method. The average output structure of TN from land use and rural life is about 66.5 and 17.1 %, the TP is about 53.8 and 32.7 %; the maximum source composition of TN (59 %) is farmland; the maximum source

  13. Leaching Mechanisms Program. Annual report

    SciTech Connect

    Dougherty, D.; Colombo, P.; Doty, R.; Fuhrmann, M.

    1984-09-01

    The primary goal of this work is to determine the leaching mechanisms of a variety of matrix materials either in use or being considered for the solidification of low-level radioactive wastes by defense and commercial waste generators. Since this program is new and did not formally begin until May of FY 84, the results reported here are few and preliminary. Efforts were concentrated in the following activities: (1) The literature search for leaching data and proposed leaching models and mechanisms for low-level waste. (2) Data base development for leaching data being compiled from the literature and from the leaching experiments in this program. (3) The selection of solidification agents for the experimental part of the program. (4) Fabrication of leach samples and initiation of leach testing. 28 references, 9 figures, 4 tables.

  14. Reducing fertilizer-nitrogen losses from rowcrop landscapes: Insights and implications from a spatially explicit watershed model

    USGS Publications Warehouse

    McLellan, Eileen; Schilling, Keith; Robertson, Dale

    2015-01-01

    We present conceptual and quantitative models that predict changes in fertilizer-derived nitrogen delivery from rowcrop landscapes caused by agricultural conservation efforts implemented to reduce nutrient inputs and transport and increase nutrient retention in the landscape. To evaluate the relative importance of changes in the sources, transport, and sinks of fertilizer-derived nitrogen across a region, we use the spatially explicit SPAtially Referenced Regression On Watershed attributes watershed model to map the distribution, at the small watershed scale within the Upper Mississippi-Ohio River Basin (UMORB), of: (1) fertilizer inputs; (2) nutrient attenuation during delivery of those inputs to the UMORB outlet; and (3) nitrogen export from the UMORB outlet. Comparing these spatial distributions suggests that the amount of fertilizer input and degree of nutrient attenuation are both important in determining the extent of nitrogen export. From a management perspective, this means that agricultural conservation efforts to reduce nitrogen export would benefit by: (1) expanding their focus to include activities that restore and enhance nutrient processing in these highly altered landscapes; and (2) targeting specific types of best management practices to watersheds where they will be most valuable. Doing so successfully may result in a shift in current approaches to conservation planning, outreach, and funding.

  15. How inhibiting nitrification affects nitrogen cycle and reduces ...

    EPA Pesticide Factsheets

    We conducted a meta-analysis of 103 nitrification inhibitor (NI) studies, and evaluated how NI application affects crop productivity and other ecosystem services in agricultural systems. Our results showed that, compared to conventional fertilizer practice, applications of NI along with nitrogen (N) fertilizer increased crop nitrogen use efficiency, crop yield, and altered the pathways and the amount of N loss to environment. NI application increased ammonia emission, but reduced nitrate leaching and nitrous oxide emission, which led to a reduction of 12.9% of the total N loss. The cost and benefit analysis showed that the economic benefit of reducing N’s environmental impacts offset the cost of NI. NI application could bring additional revenue of $163.72 ha-1 for a maize farm. Taken together, our findings show that NI application may create a win-win scenario that increases agricultural output, while reducing the negative impact on the environment. Policies that encourage NI application would reduce N’s environmental impacts. A group from Chinese Academy of Sciences, US EPA-ORD and North Carolina examined the net environmental and economic effects of nitrification inhibitors to reduce nitrate leaching associated with farm fertilizers. They conducted a meta-analysis of studies examining nitrification inhibitors, and found that NI application increased ammonia emission, but reduced nitrate leaching and nitrous oxide emission, which led to a reduction of 12.9

  16. [Effects of controlled release nitrogen fertilizer on surface water N dynamics and its runoff loss in double cropping paddy fields in Dongtinghu Lake area].

    PubMed

    Ji, Xiong-Hui; Zheng, Sheng-Xian; Lu, Yan-Hong; Liao, Yu-Lin

    2007-07-01

    By using leakage pond to simulate the double cropping paddy fields in Dongtinghu Lake area, this paper studied the effects of urea (CF) and controlled release nitrogen fertilizer (CRNF) on the dynamics of surface water pH, electrical conductivity (EC), total nitrogen (TN), ammonia nitrogen (NH4(+)-N) and nitrate nitrogen (NO3(-)-N) and the runoff loss of TN in alluvial sandy loamy paddy soil and purple calcareous clayed paddy soil, the two main paddy soils in this area. The results showed that after applying urea, the surface water TN and NH4(+)-N concentrations reached the peak at the 1st and 3rd day, respectively, and decreased rapidly then. Surface water NO3(-)-N concentration was very low, though it showed a little raise at the 3rd to 7th day after applying urea in purple calcareous clayed paddy soil. In early rice field, surface water pH rose gradually within 15 days after applying urea, while in late rice field, it did within 3 days. EC kept consistent with the dynamics of NH4(+)-N. CRNF, especially 70% N CRNF, gave rise to distinctly lower surface water pH, EC, and TN and NH4(+)-N concentrations within 15 days after application, but NO3- concentration rose slightly at late growth stages, compared with urea application. The monitoring of TN runoff loss indicated that during double cropping rice growth season, the loss amount of TN under urea application was 7.70 kg x hm(-2), accounting for 2.57% of applied urea-N. The two runoff events occurred within 20 days after urea application contributed significantly to the TN runoff loss. CRNF application resulted in a significantly lower TN concentration in runoff water from the 1st runoff event occurred within 10 days of its application, and thereafter, the total TN runoff loss for CRNF and 70% N CRNF application was decreased by 24.5% and 27.2%, respectively, compared with urea application.

  17. Effects of biochar addition to soil on nitrogen fluxes in a winter wheat lysimeter experiment

    NASA Astrophysics Data System (ADS)

    Hüppi, Roman; Leifeld, Jens; Neftel, Albrecht; Conen, Franz; Six, Johan

    2014-05-01

    Biochar is a carbon-rich, porous residue from pyrolysis of biomass that potentially increases crop yields by reducing losses of nitrogen from soils and/or enhancing the uptake of applied fertiliser by the crops. Previous research is scarce about biochar's ability to increase wheat yields in temperate soils or how it changes nitrogen dynamics in the field. In a lysimeter system with two different soils (sandy/silt loam) nitrogen fluxes were traced by isotopic 15N enriched fertiliser to identify changes in nitrous oxide emissions, leaching and plant uptake after biochar addition. 20t/ha woodchip-waste biochar (pH=13) was applied to these soils in four lysimeters per soil type; the same number of lysimeters served as a control. The soils were cropped with winter wheat during the season 2012/2013. 170 kg-N/ha ammonium nitrate fertiliser with 10% 15N was applied in 3 events during the growing season and 15N concentrations where measured at different points in time in plant, soil, leachate and emitted nitrous oxide. After one year the lysimeter system showed no difference between biochar and control treatment in grain- and straw yield or nitrogen uptake. However biochar did reduce nitrous oxide emissions in the silt loam and losses of nitrate leaching in sandy loam. This study indicates potential reduction of nitrogen loss from cropland soil by biochar application but could not confirm increased yields in an intensive wheat production system.

  18. Long-term manure incorporation with chemical fertilizers reduced environmental nitrogen loss in rain-fed cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improving soil fertility/productivity and reducing environmental impact of nitrogen (N) fertilization in intensive farming systems are essential for sustainable agriculture and food security around the world. The objective of this study was to determine the long-term effects of various fertilization...

  19. Nitrogen Cycle Modeling: a Mechanistic Estimate of N-losses From Agricultural Fields Over the Seasonal Time Period

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biogeochemical cycle of nitrogen and production of NO, N2O, and CO2 gas and NO2- and NO3- ions in nutrient-enriched agricultural fields is mediated by soil microbial activity, the hydrological cycle, plant dynamics, and climatic forcing. Understanding how NO, N2O, CO2 gases and NO2- and NO3- io...

  20. Effect of condensed tannin extract supplementation of performance, nitrogen, balance, gas emissions, and energetic losses of beef steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen emissions from concentrated animal feeding operations are of increasing concern to regulatory agencies and consumers. We evaluated the effect of top-dressing a finishing diet (14.4% crude protein) for beef steers with a commercially-available condensed tannin extract (CT) at three levels (0...

  1. Dynamic modeling of nitrogen losses in river networks unravels the coupled effects of hydrological and biogeochemical processes

    USGS Publications Warehouse

    Alexander, R.B.; Böhlke, J.K.; Boyer, E.W.; David, M.B.; Harvey, J.W.; Mulholland, P.J.; Seitzinger, S.P.; Tobias, C.R.; Tonitto, C.; Wollheim, W.M.

    2009-01-01

    The importance of lotic systems as sinks for nitrogen inputs is well recognized. A fraction of nitrogen in streamflow is removed to the atmosphere via denitrification with the remainder exported in streamflow as nitrogen loads. At the watershed scale, there is a keen interest in understanding the factors that control the fate of nitrogen throughout the stream channel network, with particular attention to the processes that deliver large nitrogen loads to sensitive coastal ecosystems. We use a dynamic stream transport model to assess biogeochemical (nitrate loadings, concentration, temperature) and hydrological (discharge, depth, velocity) effects on reach-scale denitrification and nitrate removal in the river networks of two watersheds having widely differing levels of nitrate enrichment but nearly identical discharges. Stream denitrification is estimated by regression as a nonlinear function of nitrate concentration, streamflow, and temperature, using more than 300 published measurements from a variety of US streams. These relations are used in the stream transport model to characterize nitrate dynamics related to denitrification at a monthly time scale in the stream reaches of the two watersheds. Results indicate that the nitrate removal efficiency of streams, as measured by the percentage of the stream nitrate flux removed via denitrification per unit length of channel, is appreciably reduced during months with high discharge and nitrate flux and increases during months of low-discharge and flux. Biogeochemical factors, including land use, nitrate inputs, and stream concentrations, are a major control on reach-scale denitrification, evidenced by the disproportionately lower nitrate removal efficiency in streams of the highly nitrate-enriched watershed as compared with that in similarly sized streams in the less nitrate-enriched watershed. Sensitivity analyses reveal that these important biogeochemical factors and physical hydrological factors contribute nearly

  2. Interflow, overland flow and leaching of natural nutrients on an Alfisol slope of southern Bahia, Brazil

    NASA Astrophysics Data System (ADS)

    De Oliveira Leite, J.

    1985-09-01

    Two experimental plots for hydrologic studies, 3595 and 7060 m 2, were delimited on a slope of Alfisol planted with cacao in Bahia, Brazil. Volumes of overland flow and interflow were measured daily and samples of collected water were taken monthly for analysis of Ca, Mg, Na, K, N, P and Fe. The highest overland-flow volumes represented 24% and the highest interflow 53% of the rainfall but on the average the volumes of overland flow and interflow were found to represent 1 and 14% of the annual rainfall. The percentage of interflow increases with increasing rainfall. In winter, it is higher than in summer, except during the highest rains observed. The mean annual loss for calcium was 85.8 kg ha -1 yr -1; for magnesium 18.2; potassium 17.0; sodium 23.5; nitrogen 22.1; iron 5.5 and phosphorus 0.9. In relative terms, considering the chemical components of the soils, the K losses are highest, indicating that this element is most leachable. The interflow volumes and the amounts of Na, K, N and P correlated at the 1% significance level in both plots. A general conclusion is that the leaching of nutrients varied with the intensity of the interflow, especially for Na, K, N and P, the leaching of nutrients through overland flow being of less importance.

  3. Influence of aeration rate on nitrogen dynamics during composting.

    PubMed

    de Guardia, A; Petiot, C; Rogeau, D; Druilhe, C

    2008-01-01

    The paper aimed to study the influence of aeration rate on nitrogen dynamics during composting of wastewater sludge with wood chips. Wastewater sludge was sampled at a pig slaughterhouse 24h before each composting experiment, and mixtures were made at the same mass ratio. Six composting experiments were performed in a lab reactor (300 L) under forced aeration. Aeration flow was constant throughout the experiment and aeration rates applied ranged between 1.69 and 16.63 L/h/kg DM of mixture. Material temperature and oxygen consumption were monitored continuously. Nitrogen losses in leachates as organic and total ammoniacal nitrogen, nitrite and nitrate, and losses in exhaust gases as ammonia were measured daily. Concentrations of total carbon and nitrogen i.e., organic nitrogen, total ammoniacal nitrogen, and nitrite and nitrate were measured in the initial substrates and in the composted materials. The results showed that organic nitrogen, which was released as NH4+/NH3 by ammonification, was closely correlated to the ratio of carbon removed from the material to TC/N(org) of the initial substrates. The increase of aeration was responsible for the increase in ammonia emissions and for the decrease in nitrogen losses through leaching. At high aeration rates, losses of nitrogen in leachates and as ammonia in exhaust gases accounted for 90-99% of the nitrogen removed from the material. At low aeration rates, those accounted for 47-85% of the nitrogen removed from the material. The highest concentrations of total ammoniacal nitrogen in composts occurred at the lowest aeration rate. Due to the correlation of ammonification with biodegradation and to the measurements of losses in leachates and in exhaust gases, the pool NH4+/NH3 in the composting material was calculated as a function of time. The nitrification rate was found to be proportional to the mean content of NH4+/NH3 in the material, i.e., initial NH4+/NH3 plus NH4+/NH3 released by ammonification minus losses in

  4. Air pollution and changes in forest nitrogen status: Fog and rain deposition and nitrogen losses from forested watersheds in the San Bernardino Mountains. Final report

    SciTech Connect

    Fenn, M.E.; Poth, M.A.

    1998-08-01

    The primary objective of this project was to examine the effects of N deposition on mixed conifer forests in southern California. Studies were conducted at selected sites an air pollution gradient in the San Bernardino Mountains (SBM). The main tasks were: (1) to measure N deposition to the forest in fog and throughfall, (2) to determine spatial and temporal patterns of nitrate export in stream water, and (3) to quantify trace gas fluxes from soil at sites with high and low N deposition. Fog was found to be an important N source at the western end of the SMB due to his high frequency and presence at elevated concentrations. N deposition from throughfall was found to be similar to levels in forests where adverse effects have occurred. Annual fluxes of N from soil were 18-times higher at the western end of the SBM than at the eastern end. The data provide evidence of forest nitrogen saturation caused by the deposition of anthropogenic pollutants over a multi-decade period in the SBM.

  5. The evolutionary events necessary for the emergence of symbiotic nitrogen fixation in legumes may involve a loss of nitrate responsiveness of the NIN transcription factor.

    PubMed

    Suzuki, Wataru; Konishi, Mineko; Yanagisawa, Shuichi

    2013-10-01

    NODULE INCEPTION (NIN) is a key regulator of the symbiotic nitrogen fixation pathway in legumes including Lotus japonicus. NIN-like proteins (NLPs), which are presumably present in all land plants, were recently identified as key transcription factors in nitrate signaling and responses in Arabidopsis thaliana, a non-leguminous plant. Here we show that both NIN and NLP1 of L. japonicus (LjNLP1) can bind to the nitrate-responsive cis-element (NRE) and promote transcription from an NRE-containing promoter as did the NLPs of A. thaliana (AtNLPs). However, differing from LjNLP1 and the AtNLPs that are activated by nitrate signaling through their N-terminal regions, the N-terminal region of NIN did not respond to nitrate. Thus, in the course of the evolution of NIN into a transcription factor that functions in nodulation in legumes, some mutations might arise that converted it to a nitrate-insensitive transcription factor. Because nodule formation is induced under nitrogen-deficient conditions, we speculate that the loss of the nitrate-responsiveness of NIN may be one of the evolutionary events necessary for the emergence of symbiotic nitrogen fixation in legumes.

  6. Leaching Test Relationships, Laboratory-to-Field Comparisons and Recommendations for Leaching Evaluation using the Leaching Environmental Assessment Framework (LEAF)

    EPA Science Inventory

    This report presents examples of the relationships between the results of laboratory leaching tests, as defined by the Leaching Environmental Assessment Framework (LEAF) or analogous international test methods, and leaching of constituents from a broad range of materials under di...

  7. Application of a colorimetric method to the determination of the protein content of commercial foods, mixed human diets and nitrogen losses in infantile diarrhoea.

    PubMed

    Cioccia, A M; Gonzalez, E; Perez, M; Mora, J A; Romer, H; Molina, E; Hevia, P

    1995-02-01

    Recently we reported on the application of a method for protein determination which measures nitrogen in Kjeldahl digests colorimetrically. This procedure has the advantage of eliminating the distillation and titration steps of the Kjeldahl method and it is ideal for nutritional studies, since many samples can be run in a single day. Accordingly, the purpose of the present report was to extend the application of this method to the determination of the protein content of commercially available foods such as dairy products, dry cereals or cereal based products and legumes and also to evaluate this method in the determination of the protein content of the mixtures of cooked foods served during lunch at the cafeteria of the Universidad Simón Bolívar, Caracas. In both cases the results of the colorimetric nitrogen agreed very well with those obtained by the macro Kjeldahl, indicating that the colorimetric method may be used in monitoring the protein content of commercial foods and in evaluating the protein offered in institutional food services. Finally, to further demonstrate the value of this method in clinical trials, we used it to monitor the daily nitrogen intake and nitrogen losses in 43 male young children with acute diarrhoea, and 15 with persistent diarrhoea fed liquid formulae, and showed that protein digestibility and retention were higher in persistent than in acute diarrhoea. The severity of acute diarrhoea affected negatively (r = -0.62) the percentage of protein absorbed, whereas the protein absorbed (r = 0.70) and retained (r = 0.55) correlated positively with protein consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Use of dolomite phosphate rock (DPR) fertilizers to reduce phosphorus leaching from sandy soil.

    PubMed

    Chen, G C; He, Z L; Stoffella, P J; Yang, X E; Yu, S; Calvert, D

    2006-01-01

    There is increasing concern over P leaching from sandy soils applied with water-soluble P fertilizers. Laboratory column leaching experiments were conducted to evaluate P leaching from a typical acidic sandy soil in Florida amended with DPR fertilizers developed from dolomite phosphate rock (DPR) and N-Viro soil. Ten leaching events were carried out at an interval of 7 days, with a total leaching volume of 1,183 mm equivalent to the mean annual rainfall of this region during the period of 2001-2003. Leachates were collected and analyzed for total P and inorganic P. Phosphorus in the leachate was dominantly reactive, accounting for 67.7-99.9% of total P leached. Phosphorus leaching loss mainly occurred in the first three leaching events, accounting for 62.0-98.8% of the total P leached over the whole period. The percentage of P leached (in the total P added) from the soil amended with water-soluble P fertilizer was higher than those receiving the DPR fertilizers. The former was up to 96.6%, whereas the latter ranged from 0.3% to 3.8%. These results indicate that the use of N-Viro-based DPR fertilizers can reduce P leaching from sandy soils.

  9. Linking an economic model for European agriculture with a mechanistic model to estimate nitrogen losses from cropland soil in Europe

    NASA Astrophysics Data System (ADS)

    Leip, A.; Marchi, G.; Koeble, R.; Kempen, M.; Britz, W.; Li, C.

    2007-07-01

    For the comprehensive assessment of the policy impact on greenhouse gas emissions from agricultural soils both socio-economic aspects and the environmental heterogeneity of the landscape are important factors that must be considered. We developed a modelling framework that links the large-scale economic model for agriculture CAPRI with the bio-geochemistry model DNDC to simulate greenhouse gas fluxes, carbon stock changes and the nitrogen budget of agricultural soils in Europe. The framework allows the ex-ante simulation of agricultural or agri-environmental policy impacts on wide range of environmental problems such as climate change (greenhouse gas emissions), air pollution and groundwater pollution. Those environmental impacts can be analysed in the context of economic and social indicators as calculated by the economic model. The methodology consists in four steps (i) the definition of appropriate calculation units that can be considered as homogeneous in terms of economic behaviour and environmental response; (ii) downscaling of regional agricultural statistics and farm management information from a CAPRI simulation run into the spatial calculation units; (iii) setting up of environmental model scenarios and model runs; and finally (iv) aggregating results for interpretation. We show first results of the nitrogen budget in cropland for the area of fourteen countries of the European Union. These results, in terms of estimated nitrogen fluxes, must still be considered as illustrative as needs for improvements in input data (e.g. the soil map) and management data (yield estimates) have been identified and will be the focus of future work. Nevertheless, we highlight inter-dependencies between farmer's choices of land uses and the environmental impact of different cultivation systems.

  10. Combined deep sampling and mass-based approaches to assess soil carbon and nitrogen losses due to land-use changes in karst area of southwestern China

    NASA Astrophysics Data System (ADS)

    Hu, Yecui; Du, Zhangliu; Wang, Qibing; Li, Guichun

    2016-07-01

    The conversion of natural vegetation to human-managed ecosystems, especially the agricultural systems, may decrease soil organic carbon (SOC) and total nitrogen (TN) stocks. The objective of present study was to assess SOC and TN stocks losses by combining deep sampling with mass-based calculations upon land-use changes in a typical karst area of southwestern China. We quantified the changes from native forest to grassland, secondary shrub, eucalyptus plantation, sugarcane and corn fields (both defined as croplands), on the SOC and TN stocks down to 100 cm depth using fixed-depth (FD) and equivalent soil mass (ESM) approaches. The results showed that converting forest to cropland and other types significantly led to SOC and TN losses, but the extent depended on both sampling depths and calculation methods selected (i.e., FD or ESM). On average, the shifting from native forest to cropland led to SOC losses by 19.1, 25.1, 30.6, 36.8 and 37.9 % for the soil depths of 0-10, 0-20, 0-40, 0-60 and 0-100 cm, respectively, which highlighted that shallow sampling underestimated SOC losses. Moreover, the FD method underestimated SOC and TN losses for the upper 40 cm layer, but overestimated the losses in the deeper layers. We suggest that the ESM together with deep sampling should be encouraged to detect the differences in SOC stocks. In conclusion, the conversion of forest to managed systems, in particular croplands significantly decreased in SOC and TN stocks, although the effect magnitude to some extent depended on sampling depth and calculation approach selected.

  11. Biotic Nitrogen Enrichment Regulates Calcium Sources to Forests

    NASA Astrophysics Data System (ADS)

    Pett-Ridge, J. C.; Perakis, S. S.; Hynicka, J. D.

    2015-12-01

    Calcium is an essential nutrient in forest ecosystems that is susceptible to leaching loss and depletion. Calcium depletion can affect plant and animal productivity, soil acid buffering capacity, and fluxes of carbon and water. Excess nitrogen supply and associated soil acidification are often implicated in short-term calcium loss from soils, but the long-term role of nitrogen enrichment on calcium sources and resupply is unknown. Here we use strontium isotopes (87Sr/86Sr) as a proxy for calcium to investigate how soil nitrogen enrichment from biological nitrogen fixation interacts with bedrock calcium to regulate both short-term available supplies and the long-term sources of calcium in montane conifer forests. Our study examines 22 sites in western Oregon, spanning a 20-fold range of bedrock calcium on sedimentary and basaltic lithologies. In contrast to previous studies emphasizing abiotic control of weathering as a determinant of long-term ecosystem calcium dynamics and sources (via bedrock fertility, climate, or topographic/tectonic controls) we find instead that that biotic nitrogen enrichment of soil can strongly regulate calcium sources and supplies in forest ecosystems. For forests on calcium-rich basaltic bedrock, increasing nitrogen enrichment causes calcium sources to shift from rock-weathering to atmospheric dominance, with minimal influence from other major soil forming factors, despite regionally high rates of tectonic uplift and erosion that can rejuvenate weathering supply of soil minerals. For forests on calcium-poor sedimentary bedrock, we find that atmospheric inputs dominate regardless of degree of nitrogen enrichment. Short-term measures of soil and ecosystem calcium fertility are decoupled from calcium source sustainability, with fundamental implications for understanding nitrogen impacts, both in natural ecosystems and in the context of global change. Our finding that long-term nitrogen enrichment increases forest reliance on atmospheric

  12. Frequency of deflagration in the in-tank precipitation process tanks due to loss of nitrogen purge system. Revision 2

    SciTech Connect

    Jansen, J.M.; Mason, C.L.; Olsen, L.M.; Shapiro, B.J.; Gupta, M.K.; Britt, T.E.

    1994-01-01

    High-level liquid wastes (HLLW) from the processing of nuclear material at the Savannah River Site (SRS) are stored in large tanks in the F- and H-Area tank farms. The In-Tank Precipitation (ITP) process is one step in the processing and disposal of HLLW. The process hazards review for the ITP identified the need to implement provisions that minimize deflagration/explosion hazards associated with the process. The objective of this analysis is to determine the frequency of a deflagration in Tank 48 and/or 49 due to nitrogen purge system failures (including external events) and coincident ignition source. A fault tree of the nitrogen purge system coupled with ignition source probability is used to identify dominant system failures that contribute to the frequency of deflagration. These system failures are then used in the recovery analysis. Several human actions, recovery actions, and repair activities are identified that reduce total frequency. The actions are analyzed and quantified as part of a Human Reliability Analysis (HRA). The probabilities of failure of these actions are applied to the fault tree cutsets and the event trees.

  13. A model study of the effects of intermittent loss on odd nitrogen concentrations in the lower troposphere

    NASA Technical Reports Server (NTRS)

    Stewart, R. W.; Hameed, S.; Matloff, G.

    1983-01-01

    A time-dependent box model of the lower troposphere which includes a description of photochemical and physical processes has been developed. This model has been applied to the calculation of nitric acid and NO(x)(NO + NO2) concentrations over a diurnal cycle which includes precipitation. Nitric acid concentrations and the HNO3/NO(x) ratio are found to be highly variable under the assumptions regarding the frequency, duration, and intensity of precipitation employed in this model. The chemistry of odd nitrogen compounds during the night is potentially important in establishing the level of nitric acid in the lower troposphere. These calculations also indicate that relatively large errors may occur when the continuity equation describing nitric acid variations is averaged over a diurnal cycle which includes precipitation. Interpretation of simultaneous measurements of HNO3 and NO(x) will require some knowledge of the history of the observed air mass and may require an improved understanding of nighttime odd nitrogen chemistry.

  14. Reactive Nitrogen in Atmospheric Emission Inventories

    EPA Science Inventory

    Excess reactive Nitrogen (NT) has become one of the most pressing environmental problems leading to air pollution, acidification and eutrophication of ecosystems, biodiversity impacts, leaching of nitrates into groundwater and global warming. This paper investigates how current i...

  15. Using biophysical models to manage nitrogen pollution from agricultural sources: Utopic or realistic approach for non-scientist users? Case study of a drinking water catchment area in Lorraine, France.

    PubMed

    Bernard, Pierre-Yves; Benoît, Marc; Roger-Estrade, Jean; Plantureux, Sylvain

    2016-12-01

    The objectives of this comparison of two biophysical models of nitrogen losses were to evaluate first whether results were similar and second whether both were equally practical for use by non-scientist users. Results were obtained with the crop model STICS and the environmental model AGRIFLUX based on nitrogen loss simulations across a small groundwater catchment area (<1 km(2)) located in the Lorraine region in France. Both models simulate the influences of leaching and cropping systems on nitrogen losses in a relevant manner. The authors conclude that limiting the simulations to areas where soils with a greater risk of leaching cover a significant spatial extent would likely yield acceptable results because those soils have more predictable leaching of nitrogen. In addition, the choice of an environmental model such as AGRIFLUX which requires fewer parameters and input variables seems more user-friendly for agro-environmental assessment. The authors then discuss additional challenges for non-scientists such as lack of parameter optimization, which is essential to accurately assessing nitrogen fluxes and indirectly not to limit the diversity of uses of simulated results. Despite current restrictions, with some improvement, biophysical models could become useful environmental assessment tools for non-scientists.

  16. Runoff losses of phosphorus and nitrogen in a corn silage system: A field-scale paired watershed approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transport of P, N, and sediment via runoff from crop fields, especially where manure has been applied, can contribute to eutrophication and degradation of surface waters. We established a paired-watershed field site to evaluate surface runoff losses of nutrients and sediment from different manure/cr...

  17. Results of rainfall simulation to estimate sediment-bound carbon and nitrogen loss from an Atlantic Coastal Plain (USDA) ultisol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of erosion on soil and carbon loss and redistribution within landscapes is an important component for developing estimates of carbon sequestration potential, management plans to maintain soil quality, and transport of sediment bound agrochemicals. Soils of the Southeastern U.S. Coastal Pl...

  18. Preferential flow, nitrogen transformations and 15N balance under urine-affected areas of irrigated and non-irrigated clover-based pastures

    NASA Astrophysics Data System (ADS)

    Pakro, Naser; Dillon, Peter

    1995-12-01

    Urine-affected areas can lead to considerable losses of N by leaching, ammonia volatilisation and denitrification from dairy pastures in the southeast of South Australia. Potable groundwater supplies are considered to have become contaminated by nitrate as a result of leaching from these leguminous pastures. Dairy cow urine, labelled with 15N urea, was applied to micro-plots and mini-lysimeters installed in two adjacent irrigated (white clover-rye grass) and non-irrigated (subterranean clover-annual grasses) paddocks of a dairy farm on four occasions representing different seasonal conditions. These experiments allowed measurement of nitrogen transformations, recovery of 15N in the pasture and soil, and leaching below various depths. Gaseous losses were calculated from the nitrogen balance. The results of the four experiments showed that within a day of urine application up to 40% of the applied urinary-N was leached below a depth of 150 mm as a result of macropore flow in the irrigated paddock, and up to 24% in the non-irrigated one. After application to the irrigated paddock 17% of the urinary-N moved immediately below 300 mm but only 2% below the 450-mm depth. The urinary-N remaining in the soil was converted from urea to ammonium within a day regardless of season. Within the first 7 days of application six times more nitrate was produced in summer than in winter. This has obvious implications for leaching potential. Leaching of 15N from the top 150 mm of soil, following urine applications in all seasons, was between 41% and 62% of the applied 15N in the irrigated paddock and 25-51% in the non-irrigated paddock. However, leaching losses measured at depths of 300 or 450 mm were smaller by a factor of 2-4. The leaching loss of 15N applied in spring in both paddocks was 41% below 150 mm and 12% below 450 mm. Recovery of 15N from the soil-plant system in the 450-nm deep lysimeters was ˜60% of that applied. Estimated ammonia was ˜9% of applied 15N with no paddock

  19. Leaching of mixtures of biochar and fly ash

    SciTech Connect

    Palumbo, Anthony V.; Porat, Iris; Phillips, Jana R.; Amonette, James E.; Drake, Meghan M.; Brown, Steven D.; Schadt, Christopher W.

    2009-06-22

    Increasing atmospheric levels of greenhouse gases, especially CO2, and their effects on global temperature have led to interest in the possibility of carbon storage in terrestrial environments. Both the residual char from biomass pyrolysis (biochar) and fly ash from coal combustion have the potential to significantly expand terrestrial sequestration options. Both biochar and fly ash also have potentially beneficial effects on soil properties. Fly ash has been shown to increase porosity, water-holding capacity, pH, conductivity, and dissolved SO42-, CO32-, Cl- and basic cations. Adding biochar to soil generally raises pH, increases total nitrogen and total phosphorous, encourages greater root development, improves cation exchange capacity and decreases available aluminum. A combination of these benefits likely is responsible for observed increases in yields for crops such as corn and sugarcane. In addition, it has been found that soils with added biochar emit lower amounts of other greenhouse gases (methane and nitrous oxide) than do unamended soils. Biochar and fly ash amendments may be useful in promoting terrestrial carbon sequestration on currently underutilized and degraded lands. For example, about 1% of the US surface lands consist of previously mined lands or highway rights-of-way. Poorly managed lands could count for another 15% of US area. Biochar and fly ash amendments could increase productivity of these lands and increase carbon storage in the soil. Previous results showed minimal leaching of organic carbon and metals from a variety of fly ashes. In the present study, we examined the properties of mixtures of biochar, fly ash, and soil and evaluated the leaching of organic carbon and metals from these mixtures. The carbon sorption experiments showed release of carbon from biochar, rather than sorption, except at the highest concentrations in the Biochar HW sample. Similar results were obtained by others for oxidative leaching of bituminous coal, in

  20. Upgrading ferrochromium to chromium by nitriding, leaching, and dissociation

    NASA Astrophysics Data System (ADS)

    Kirby, A. W.; Fray, D. J.

    1989-04-01

    A process for the upgrading of the chromium content of ferrochromium powder has been investigated on a laboratory scale. The overall process consists of nitriding the ferrochromium to form Fe4N and CrN, which exist as two separate phases. In acidic solution, Fe4N reacts readily, whereas under certain conditions, CrN is inert; this offers a selective way of removing the iron phase. Finally, the CrN can be dissociated under moderate vacuum at elevated temperatures to yield chromium containing 2 pct iron and less than 0.05 pct nitrogen. The kinetics and equilibria of nitriding using nitrogen and ammonia have been studied as a function of temperature and gas composition. X-ray powder diffraction identified CrN, Cr2N, FeN, and Fe4N with the relative proportions varying with the nitriding conditions. As the lower nitride Cr2N, which formed on nitriding above 1073 K, was found to be susceptible to attack by acids, the iron was leached from samples nitrided below 1073 K where the products consisted of CrN and Fe4N. The optimum efficiency of iron leaching was found to depend upon the nitriding and leaching times, leaching temperatures, stirring rates, and acid concentrations. The dissociation of CrN was examined in a vacuum furnace, and dissociation was found to proceed rapidly above 1423 K.

  1. Low-disturbance manure incorporation effects on ammonia and nitrate loss.

    PubMed

    Dell, Curtis J; Kleinman, Peter J A; Schmidt, John P; Beegle, Douglas B

    2012-01-01

    Low-disturbance manure application methods can provide the benefits of manure incorporation, including reducing ammonia (NH3) emissions, in production systems where tillage is not possible. However, incorporation can exacerbate nitrate (NO3⁻) leaching. We sought to assess the trade-offs in NH3 and NO3⁻ losses caused by alternative manure application methods. Dairy slurry (2006-2007) and liquid swine manure (2008-2009) were applied to no-till corn by (i) shallow (<10 cm) disk injection, (ii) surface banding with soil aeration, (iii) broadcasting, and (iv) broadcasting with tillage incorporation. Ammonia emissions were monitored for 72 h after application using ventilated chambers and passive diffusion samplers, and NO3⁻ leaching to 80 cm was monitored with buried column lysimeters. The greatest NH3 emissions occurred with broadcasting (35-63 kg NH3-N ha⁻), and the lowest emissions were from unamended soil (<1 kg NH-N ha⁻¹). Injection decreased NH-N emissions by 91 to 99% compared with broadcasting and resulted in lower emissions than tillage incorporation 1 h after broadcasting. Ammonia-nitrogen emissions from banding manure with aeration were inconsistent between years, averaging 0 to 71% that of broadcasting. Annual NO3⁻ leaching losses were small (<25 kg NO3-N ha⁻¹) and similar between treatments, except for the first winter when NO3⁻ leaching was fivefold greater with injection. Because NO3⁻ leaching with injection was substantially lower over subsequent seasons, we hypothesize that the elevated losses during the first winter were through preferential flow paths inadvertently created during lysimeter installation. Overall, shallow disk injection yielded the lowest NH3 emissions without consistently increasing NO3⁻ leaching, whereas manure banding with soil aeration conserved inconsistent amounts of N.

  2. MODELS FOR LEACHING OF PESTICIDES IN SOILS AND GROUNDWATER

    EPA Science Inventory

    Models are developed which describe leaching of pesticides in the root zone and the intermediate vadose zone, and flushing of residual solute mass in the aquifer. Pollutants' loss pathways in the soil, such as volatilization, crop uptake, and biochemical decay, are emphasized, a...

  3. Next Generation of Leaching Tests

    EPA Science Inventory

    A corresponding abstract has been cleared for this presentation. The four methods comprising the Leaching Environmental Assessment Framework are described along with the tools to support implementation of the more rigorous and accurate source terms that are developed using LEAF ...

  4. Influence of soil structure on contaminant leaching from injected slurry.

    PubMed

    Amin, M G Mostofa; Pedersen, Christina Østerballe; Forslund, Anita; Veith, Tamie L; Laegdsmand, Mette

    2016-12-15

    Animal manure application to agricultural land provides beneficial organic matter and nutrients but can spread harmful contaminants to the environment. Contamination of fresh produce, surface water and shallow groundwater with the manure-borne pollutants can be a critical concern. Leaching and persistence of nitrogen, microorganisms (bacteriophage, E. coli, and Enterococcus) and a group of steroid hormone (estrogens) were investigated after injection of swine slurry into either intact (structured) or disturbed (homogeneous repacked) soil. The slurry was injected into hexaplicate soil columns at a rate of 50 t ha(-1) and followed with four irrigation events: 3.5-h period at 10 mm h(-1) after 1, 2, 3, and 4 weeks. The disturbed columns delayed the leaching of a conservative tracer and microorganisms in the first irrigation event compared to the intact columns due to the effect of disturbed macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils. In contrast, NO3-N leaching from the intact soil was higher for all events except the first event, probably due to a lower nitrification rate in the disturbed soil. A week after the last irrigation event, the redistribution of all slurry constituents except NO3-N in most of the sections of the soil column was higher for the disturbed soil. Total recovery of E. coli was significantly higher from the disturbed soil and total leaching of mineral nitrogen was significantly lower

  5. Atmospheric nitrate leached from small forested watersheds during rainfall events: Processes and quantitative evaluation

    NASA Astrophysics Data System (ADS)

    Osaka, Ken'ichi; Kugo, Tatsuro; Komaki, Naoto; Nakamura, Takashi; Nishida, Kei; Nagafuchi, Osamu

    2016-08-01

    To determine the availability of atmospheric NO3- deposition on forested ecosystems and to understand the interaction between the nitrogen cycle in a forest ecosystem and atmospheric nitrogen input/output, we quantitatively evaluated the atmospheric NO3- passing through forested watersheds by measuring δ18ONO3 leaching during rainfall events in two forest ecosystems (Su-A and Ab-S). Atmospheric NO3- leaching in rainfall events was clearly higher in Ab-S than in Su-A, even for a similar amount of rainfall, which demonstrated that atmospheric NO3- leaching differs among forested watersheds. Our observations suggest that a large part of the atmospheric NO3- leached from the watersheds was derived from surface soil, which was deposited before rainfall events occurred; however, direct atmospheric NO3- leaching via throughfall discharge also contributed, especially at the beginning of rainfall events. In Ab-S, 2.9-37.8% (average = 15.5%) of atmospheric NO3- deposition passed through the watershed, accounting for 3.1-49.8% (average, 26.4%) of the total NO3- leached during rainfall events. The NO3- input was not large, and the NO3- pool and net nitrification rate were small; therefore, nitrogen was not saturated in the soil at Ab-S. Nevertheless, some of the atmospheric NO3- deposition was not assimilated and was leached immediately. Moreover, our observations suggest that the hydrological characteristics of the watersheds, which control the ease of rainwater discharge, strongly influenced the rate of atmospheric NO3- leaching. This suggests that the hydrological characteristics of watersheds influence the availability of atmospheric NO3- deposition in forested ecosystems and the progression of nitrogen saturation.

  6. Mitigation alternatives to decrease nitrous oxides emissions and urea-nitrogen loss and their effect on methane flux

    SciTech Connect

    Delgado, J.A.; Mosier, A.R.

    1996-09-01

    Nitrous oxide (N{sub 2}O) and methane (CH{sub 4}) are greenhouse gases that are contributing to global warming potential. Nitrogen (N) fertilizer is one of the most important sources of anthropogenic N{sub 2}O emissions. A field study was conducted to compare N-use efficiency and effect on N{sub 2}O and CH{sub 4} flux, of urea plus the nitrification inhibitor dicyandiamide (U + DCD), and a control release fertilizer, polyolefin coated urea (POCU) in irrigated spring barley (Hordeum vulgare L.) in northeastern Colorado. Each treatment received 90 kg urea-N ha{sup -1} and microplots labeled with {sup 15}N-fertilizer were established. Average N{sub 2}O emissions were 4.5, 5.2, 6.9, and 8.2 g N ha{sup -1} d{sup -1} for control, U + DCD, POCU, and urea, respectively. During the initial 21 d after fertilization, N{sub 2}P emissions were reduced by 82 and 71% in the U + DCD and POCU treatments, respectively, but continued release of N fertilizer from POCU maintained higher N{sub 2}O emissions through the remainder of the growing season. No treatment effect on CH{sub 4} oxidation in soils was observed. Fertilizer {sup 15}N found 50 to 110 cm cm below the soil surface was lower in the POCU and U + DCD treatments. At harvest, recovery of {sup 15}N-fertilizer in the plant-soil system was 98, 90, and 85% from POCU, urea, and U + DCD, respectively. Grain yield was 2.2, 2.5, and 2.7 Mg ha{sup -1} for POCU, urea, and U + DCD, respectively. Dicyandiamide and POCU showed the potential to be used as mitigation alternatives to decrease N{sub 2}O emissions from N fertilizer and movement of N out of the root zone, but N release from POCU does need to be formulated to better match crop growth demands. 46 refs., 1 figs., 4 tabs.

  7. Use of Zeolite with Alum and Polyaluminum Chloride Amendments to Mitigate Runoff Losses of Phosphorus, Nitrogen, and Suspended Solids from Agricultural Wastes Applied to Grassed Soils.

    PubMed

    Murnane, J G; Brennan, R B; Healy, M G; Fenton, O

    2015-09-01

    Diffuse pollutant losses containing phosphorus (P), nitrogen (N), and suspended solids (SS) can occur when agricultural wastes are applied to soil. This study aimed to mitigate P, N, and SS losses in runoff from grassed soils, onto which three types of agricultural wastes (dairy slurry, pig slurry, and dairy-soiled water [DSW]), were applied by combining amendments of either zeolite and polyaluminum chloride (PAC) with dairy and pig slurries or zeolite and alum with DSW. Four treatments were investigated in rainfall simulation studies: (i) control soil, (ii) agricultural wastes, (iii) dairy and pig slurries amended with PAC and DSW amended with alum, and (iv) dairy and pig slurries amended with zeolite and PAC and DSW amended with zeolite and alum. Our data showed that combined amendments of zeolite and PAC applied to dairy and pig slurries reduced total P (TP) in runoff by 87 and 81%, respectively, compared with unamended slurries. A combined amendment of zeolite and alum applied to DSW reduced TP in runoff by 50% compared with unamended DSW. The corresponding reductions in total N (TN) were 56% for dairy slurry and 45% for both pig slurry and DSW. Use of combined amendments reduced SS in runoff by 73 and 44% for dairy and pig slurries and 25% for DSW compared with unamended controls, but these results were not significantly different from those using chemical amendments only. The findings of this study are that combined amendments of zeolite and either PAC or alum reduce TP and TN losses in runoff to a greater extent than the use of single PAC or alum amendments and are most effective when used with dairy slurry and pig slurry but less effective when used with DSW.

  8. Disruption of metal ion homeostasis in soils is associated with nitrogen deposition-induced species loss in an Inner Mongolia steppe

    NASA Astrophysics Data System (ADS)

    Tian, Q.-Y.; Liu, N.-N.; Bai, W.-M.; Li, L.-H.; Zhang, W.-H.

    2015-01-01

    Enhanced deposition of atmospheric nitrogen (N) resulting from anthropogenic activities has negative impacts on plant diversity in grassland ecosystems globally. Several mechanisms have been proposed to explain the species loss. Ion toxicity due to N deposition-induced soil acidification has been suggested to be responsible for species loss in acidic grasslands, while few studies have evaluated the role of soil-mediated homeostasis of ions in species loss under elevated N deposition in alkaline grasslands. To determine whether soil-mediated processes are involved in changes in species composition by N deposition, the effects of 9 yr N addition on soil properties, aboveground biomass (AGB) and species composition were investigated in an Inner Mongolia steppe. Low to moderate N addition rate (2, 4, 8 g N m-2 yr-1) significantly enhanced AGB of grasses, while high N addition rate (> 16 g N m-2 yr-1) reduced AGB of forbs, leading to an overall increase in AGB of the community under low to moderate N addition rates. Forb richness was significantly reduced by N addition at rates greater than 8 g N m-2 yr-1, while no effect of N addition on grass richness was observed, resulting in decline in total species richness. N addition depleted base cations (Ca2+, Mg2+ and K+) in soils, reduced soil pH and mobilized Mn2+, Fe3+ and Cu2+ ions in soils. Soil inorganic-N concentration was negatively correlated with forb richness, explaining 27.2% variation of forb richness. The concentrations of base cations (Ca2+ and Mg2+) and metal ions (Mn2+ and Cu2+) showed positively and negatively linear correlation with forb richness, accounting for 25.9 and 41.4% variation of forb richness, respectively. These results reveal that disruption of metal ion homeostasis in soils by N addition, particularly enhanced release of soil Mn2+ and Cu2+ may be associated with reduction in forb richness in temperate steppe of Inner Mongolia.

  9. [Characteristics of nitrogen and phosphorus runoff losses from croplands with different planting patterns in a riverine plain area of Zhejiang Province, East China].

    PubMed

    Zhang, Ming-Kui; Wang, Yang; Huang, Chao

    2011-12-01

    By the method of site-specific observation, and selecting 27 field plots with 7 planting patterns in Shaoxing county of Zhejiang Province as test objects, this paper studied the characteristics of nitrogen (N) and phosphorous (P) runoff losses, loads, and their affecting factors in the croplands with different planting patterns in riverine plain area of the Province under natural rainfall. The mean annual runoff loads of total P, dissolved P, and particulate P from the field plots were 4.75, 0.74 and 4.01 kg x hm(-2), respectively, and the load of particulate P was much higher than that of dissolved P. The mean annual runoff loads of total N, dissolved total N, dissolved organic N, NH4(+)-N, and NO3(-)-N were 21.87, 17.19, 0.61, 3.63 and 12.95 kg x hm(-2), respectively, and the load of different fractions of dissolved total N was in the sequence of NO3(-)-N > NH4(+)-N > dissolved organic N. As for the field plots with different planting patterns, the runoff loads of total N, dissolved total N, dissolved organic N, and NO3(-)-N were in the sequence of fallow land < nursery land < single late rice field < double rice field < rape (or wheat)-single late rice field < wheat-early rice-late rice field < vegetable field, while those of total P and particulate P were in the sequence of fallow land < nursery land < single late rice field and double rice field < wheat-early rice-late rice field < rape (wheat)-single late rice field < vegetable field. No significant difference was observed in the load of water-dissolved P among the test plots with different planting patterns. The runoff losses of N and P mainly occurred in crop growth period, and the proportions of N and P losses in the growth period increased with increasing multiple crop index. The runoff losses of total N, dissolved N, and NO3(-)-N were mainly related to the application rate of N fertilizer, and soil NO3(-)-N content also had obvious effects on the runoff losses of total N and dissolved N. The runoff loss

  10. Nitrate leaching beneath a containerized nursery crop receiving trickle or overhead irrigation.

    PubMed

    Colangelo, D J; Brand, M H

    2001-01-01

    Container production of nursery crops is intensive and a potential source of nitrogen release to the environment. This study was conducted to determine if trickle irrigation could be used by container nursery producers as an alternative to standard overhead irrigation to reduce nitrogen release into the environment. The effect of overhead irrigation and trickle irrigation on leachate nitrate N concentration, flow-weighted nitrate N concentration, leachate volume, and plant growth was investigated using containerized rhododendron (Rhododendron catawbiense Michx. 'Album') supplied with a controlled-release fertilizer and grown outdoors on top of soil-monolith lysimeters. Leachate was collected over two growing seasons and overwinter periods, and natural precipitation was allowed as a component of the system. Precipitation accounted for 69% of the water entering the overhead-irrigated system and 80% of the water entering the trickle-irrigated system. Leachate from fertilized plants exceeded the USEPA limit of 10 mg L(-1) at several times and reached a maximum of 26 mg L(-1) with trickle irrigation. Average annual loss of nitrate N in leachate for fertilized treatments was 51.8 and 60.5 kg ha(-1) for the overhead and trickle treatments, respectively. Average annual flow-weighted concentration of nitrate N in leachate of fertilized plants was 7.2 mg L(-1) for overhead irrigation and 12.7 mg L(-1) for trickle irrigation. Trickle irrigation did not reduce the amount of nitrate N leached from nursery containers when compared with overhead irrigation because precipitation nullified the potential benefits of reduced leaching fractions and irrigation inputs provided under trickle irrigation.

  11. The impact of exogenous N supply on soluble organic nitrogen dynamics and nitrogen balance in a greenhouse vegetable system.

    PubMed

    Liang, Bin; Kang, Lingyun; Ren, Tao; Junliang, Li; Chen, Qing; Wang, Jingguo

    2015-05-01

    A long-term greenhouse experiment (2004-2012) was conducted with continuous tomato (Lycopersicum esculentum Mill.) plantings to understand the influence of an exogenous nitrogen supply from irrigation water, chemical fertilizer, or organic amendment on the N balance and soluble organic nitrogen (SON). The results from 16 tomato growing seasons indicated that the application of organic amendment (manure and straw) alone (Or-N) resulted in the same yield as the conventional chemical N with organic amendment (Co-N) and the reduced chemical N with organic amendment (Re-N) treatments. The annual apparent N loss was >1000 and 438 kg N ha(-1) in the Co-N and Re-N treatments, respectively. Over the study period, the SON in the 1.8 m soil profile was 1449 and 1978 kg N ha(-1) in the Re-N and Co-N treatments, respectively, it was 1.7- and 2.3-fold higher than that observed in the Or-N treatment, which indicated that SON increased with the chemical N application. The percentage of SON in the cumulative soluble N (SON plus mineral N) ranged from 28% to 44%, and there were no significant differences across the 0-0.6, 0.6-1.2, and 1.2-1.8 m soil profile, which indicated that the leaching and distribution of SON was similar to those of the mineral N in the 0-1.8 m soil profile. We conclude that the mobility of soluble organic N in the 0-1.8 m of the soil was synchronous with the mineral N under a greenhouse production system, and the risk of soluble organic N leaching increased with inorganic N application rate. Therefore, leaching of SON in the intensive agriculture should not be ignored when evaluating the risk of N leaching.

  12. Effect of Tillage and Non-tillage Agricultural Practice on Nitrogen Losses as NO and N2O in Tropical Corn Fields at Guarico State, Venezuela.

    NASA Astrophysics Data System (ADS)

    Marquina, S.; Rojas, A.; Donoso, L.; Rasse, R.; Giuliante, A.; Corona, O.; Perez, T.

    2007-12-01

    We evaluated the effect of agricultural practices on NO and N2O emissions from corn fields at Northern Guárico, one of Venezuelan largest cereal production regions. Historically, the most common agricultural practice in these regions has been mono cropping. Tillage (T) and non-tillage (NT) of soils represent approximately 30 and 70% of the planted area, respectively. Comparative studies of the nitrogen losses associated with these agricultural practices are not available for these regions. This study was conducted at the farm "Tierra Nueva", Guárico State (9° 23' 33'' N, 66° 38' 30'' W) in two corn fields under tillage and non-tillage agricultural practice during the growing season (June-August 2006). A dry tropical forest, the primary ecosystem of the region, was evaluated for the same period of time. The corn and the forest fields were adjacent; therefore, they were exposed to the same meteorological conditions. The mean annual precipitation of the area is 622±97.3 mm (last 5 years). The soils are Vertisols (Typic Haplusterts). Nutrient soil concentrations (as nitrate and ammonium), water soil content and pH soil were measured in the fields for the same period of time. Soils were fertilized and planted simultaneously by a planting machine provided with a furrow opener where the fertilizer and seeds are incorporated between 0-10 cm depths. Tillage soils were fertilized on June 1st 2006 with 65 kgN/ha of NPK (13:18:16/3MgO, 3S; N as NH4Cl), whereas non-tillage soils were fertilized the next day with 56 kgN/ha of NPK (12:25:12/3MgO, 3S; N as NH4Cl). Second fertilization of both fields was done thirty-seven days later by broadcast adding 58 kgN/ha approximately, using nitrophosphate as fertilizer (NP 33-3: 33% N total; 16.7% N- NO3- and 16.6% N- NH4+). In general, NO and N2O soil emissions from both corn fields increased after fertilization events, and depend on water soil content and nutrient soil concentration. N2O soil emissions were 11 and 9 times larger in

  13. Monitoring of nitrate leaching in sandy soils: comparison of three methods.

    PubMed

    Zotarelli, Lincoln; Scholberg, Johannes M; Dukes, Michael D; Muñoz-Carpena, Rafael

    2007-01-01

    Proper N fertilizer and irrigation management can reduce nitrate leaching while maintaining crop yield, which is critical to enhance the sustainability of vegetable production on soils with poor water and nutrient-holding capacities. This study evaluated different methods to measure nitrate leaching in mulched drip-irrigated zucchini, pepper, and tomato production systems. Fertigation rates were 145 and 217 kg N ha(-1) for zucchini; 192 and 288 kg N ha(-1) for pepper; and 208 and 312 kg N ha(-1) for tomato. Irrigation was either applied at a fixed daily rate or based on threshold values of soil moisture sensors placed in production beds. Ceramic suction cup lysimeters, subsurface drainage lysimeters and soil cores were used to access the interactive effects of N rate and irrigation management on N leaching. Irrigation treatments and N rate interaction effects on N leaching were significant for all crops. Applying N rates in excess of standard recommendations increased N leaching by 64, 59, and 32%, respectively, for pepper, tomato, and zucchini crops. Independent of the irrigation treatment or nitrogen rate, N leaching values measured from the ceramic cup lysimeter-based N leaching values were lower than the values from the drainage lysimeter and soil coring methods. However, overall nitrate concentration patterns were similar for all methods when the nitrate concentration and leached volume were relatively low.

  14. How inhibiting nitrification affects nitrogen cycle and reduces environmental impacts of anthropogenic nitrogen input.

    PubMed

    Qiao, Chunlian; Liu, Lingli; Hu, Shuijin; Compton, Jana E; Greaver, Tara L; Li, Quanlin

    2015-03-01

    Anthropogenic activities, and in particular the use of synthetic nitrogen (N) fertilizer, have doubled global annual reactive N inputs in the past 50-100 years, causing deleterious effects on the environment through increased N leaching and nitrous oxide (N2 O) and ammonia (NH3 ) emissions. Leaching and gaseous losses of N are greatly controlled by the net rate of microbial nitrification. Extensive experiments have been conducted to develop ways to inhibit this process through use of nitrification inhibitors (NI) in combination with fertilizers. Yet, no study has comprehensively assessed how inhibiting nitrification affects both hydrologic and gaseous losses of N and plant nitrogen use efficiency. We synthesized the results of 62 NI field studies and evaluated how NI application altered N cycle and ecosystem services in N-enriched systems. Our results showed that inhibiting nitrification by NI application increased NH3 emission (mean: 20%, 95% confidential interval: 33-67%), but reduced dissolved inorganic N leaching (-48%, -56% to -38%), N2 O emission (-44%, -48% to -39%) and NO emission (-24%, -38% to -8%). This amounted to a net reduction of 16.5% in the total N release to the environment. Inhibiting nitrification also increased plant N recovery (58%, 34-93%) and productivity of grain (9%, 6-13%), straw (15%, 12-18%), vegetable (5%, 0-10%) and pasture hay (14%, 8-20%). The cost and benefit analysis showed that the economic benefit of reducing N's environmental impacts offsets the cost of NI application. Applying NI along with N fertilizer could bring additional revenues of $163 ha(-1)  yr(-1) for a maize farm, equivalent to 8.95% increase in revenues. Our findings showed that NIs could create a win-win scenario that reduces the negative impact of N leaching and greenhouse gas production, while increases the agricultural output. However, NI's potential negative impacts, such as increase in NH3 emission and the risk of NI contamination, should be fully

  15. NEXT GENERATION LEACHING TESTS FOR EVALUATING LEACHING OF INORGANIC CONSTITUENTS

    EPA Science Inventory

    In the U.S. as in other countries, there is increased interest in using industrial by-products as alternative or secondary materials, helping to conserve virgin or raw materials. The LEAF and associated test methods are being used to develop the source term for leaching or any i...

  16. Zinc leaching from tire crumb rubber.

    PubMed

    Rhodes, Emily P; Ren, Zhiyong; Mays, David C

    2012-12-04

    Because tires contain approximately 1-2% zinc by weight, zinc leaching is an environmental concern associated with civil engineering applications of tire crumb rubber. An assessment of zinc leaching data from 14 studies in the published literature indicates that increasing zinc leaching is associated with lower pH and longer leaching times, but the data display a wide range of zinc concentrations, and do not address the effect of crumb rubber size or the dynamics of zinc leaching during flow through porous crumb rubber. The present study was undertaken to investigate the effect of crumb rubber size using the synthetic precipitation leaching procedure (SPLP), the effect of exposure time using quiescent batch leaching tests, and the dynamics of zinc leaching using column tests. Results indicate that zinc leaching from tire crumb rubber increases with smaller crumb rubber and longer exposure time. Results from SPLP and quiescent batch leaching tests are interpreted with a single-parameter leaching model that predicts a constant rate of zinc leaching up to 96 h. Breakthrough curves from column tests displayed an initial pulse of elevated zinc concentration (~3 mg/L) before settling down to a steady-state value (~0.2 mg/L), and were modeled with the software package HYDRUS-1D. Washing crumb rubber reduces this initial pulse but does not change the steady-state value. No leaching experiment significantly reduced the reservoir of zinc in the crumb rubber.

  17. Leaching behavior of glass ceramic nuclear waste forms

    SciTech Connect

    Lokken, R.O.

    1981-11-01

    Glass ceramic waste forms have been investigated as alternatives to borosilicate glasses for the immobilization of high-level radioactive waste at Pacific Northwest Laboratory (PNL). Three glass ceramic systems were investigated, including basalt, celsian, and fresnoite, each containing 20 wt % simulated high-level waste calcine. Static leach tests were performed on seven glass ceramic materials and one parent glass (before recrystallization). Samples were leached at 90/sup 0/C for 3 to 28 days in deionized water and silicate water. The results, expressed in normalized elemental mass loss, (g/m/sup 2/), show comparable releases from celsian and fresnoite glass ceramics. Basalt glass ceramics demonstrated the lowest normalized elemental losses with a nominal release less than 2 g/m/sup 2/ when leached in polypropylene containers. The releases from basalt glass ceramics when leached in silicate water were nearly identical with those in deionized water. The overall leachability of celsian and fresnoite glass ceramics was improved when silicate water was used as the leachant.

  18. Disruption of metal ion homeostasis in soils is associated with nitrogen deposition-induced species loss in an Inner Mongolia steppe

    NASA Astrophysics Data System (ADS)

    Tian, Q.-Y.; Liu, N.-N.; Bai, W.-M.; Li, L.-H.; Zhang, W.-H.

    2015-06-01

    Enhanced deposition of atmospheric nitrogen (N) resulting from anthropogenic activities has negative impacts on plant diversity in ecosystems. Several mechanisms have been proposed to explain the species loss. Ion toxicity due to N deposition-induced soil acidification has been suggested to be responsible for species loss in acidic grasslands, while few studies have evaluated the role of soil-mediated homeostasis of ions in species loss under elevated N deposition in grasslands with neutral or alkaline soils. To determine whether soil-mediated processes are involved in changes in biodiversity induced by N deposition, the effects of 9-year N addition on soil properties, aboveground biomass (AGB) and species richness were investigated in an Inner Mongolia steppe. Low to moderate N addition rate (2, 4, 8 g N m-2 yr-1) significantly enhanced AGB of graminoids, while high N addition rate (≥ 16 g N m-2 yr-1) reduced AGB of forbs, leading to an overall increase in AGB of the community under low to moderate N addition rates. Forb richness was significantly reduced by N addition at rates greater than 8 g N m-2 yr-1, while no effect of N addition on graminoid richness was observed, resulting in decline in total species richness. N addition reduced soil pH, depleted base cations (Ca2+, Mg2+ and K+) and mobilized Mn2+, Fe3+, Cu2+ and Al3+ ions in soils. Soil inorganic-N concentration was negatively correlated with forb richness and biomass, explaining 23.59% variation of forb biomass. The concentrations of base cations (Ca2+ and Mg2+) and metal ions (Mn2+, Cu2+ and, Fe3+) showed positively and negatively linear correlation with forb richness, respectively. Changes in the metal ion concentrations accounted for 42.77% variation of forb richness, while reduction of base cations was not associated with the reduction in forb richness. These results reveal that patterns of plant biodiversity in the temperate steppe of Inner Mongolia are primarily driven by increases in metal ion

  19. The impact of the Nitrates Directive on nitrogen emissions from agriculture in the EU-27 during 2000-2008.

    PubMed

    Velthof, G L; Lesschen, J P; Webb, J; Pietrzak, S; Miatkowski, Z; Pinto, M; Kros, J; Oenema, O

    2014-01-15

    A series of environmental policies have been implemented in the European Union (EU) to decrease nitrogen (N) emissions from agriculture. The Nitrates Directive (ND) is one of the main policies; it aims to reduce nitrate leaching from agriculture through a number of measures. A study was carried out to quantify the effects of the ND in the EU-27 on the leaching and runoff of nitrate (NO3(-)) to groundwater and surface waters, and on the emissions of ammonia (NH3), nitrous oxide (N2O), nitrogen oxides (NO(x)) and dinitrogen (N2) to the atmosphere. We formulated a scenario with and a scenario without implementation of the ND. The model MITERRA-Europe was used to calculate N emissions on a regional level in the EU-27 for the period 2000-2008. The calculated total N loss from agriculture in the EU-27 was 13 Mton N in 2008, with 53% as N2, 22% as NO3, 21% as NH3, 3% as N2O, and 1% as NO(x). The N emissions and leaching in the EU-27 slightly decreased in the period 2000-2008. Total emissions in the EU in 2008 were smaller with implementation of the ND than without the ND, by 3% for NH3, 6% for N2O, 9% for NO(x), and 16% for N leaching and runoff in 2008. However, regional differences were large. The lower emissions with ND were mainly due to the lower N inputs by fertilizers and manures. In conclusion, implementation of the ND decreased both N leaching losses to ground and surface waters, and gaseous emissions to the atmosphere. It is expected that the ND will result in a further decrease in N emissions in EU-27 in the near future, because the implementation of the measures for the ND is expected to become more strict.

  20. Leaching behaviour of synthetic aggregates.

    PubMed

    van der Sloot, H A; Hoede, D; Cresswell, D J; Barton, J R

    2001-01-01

    In the framework of EU project "Utilising innovative kiln technology to recycle waste into synthetic aggregate" (BRST-CT98-5234), the leaching behaviour of synthetic aggregates has been studied to assess its environmental compatibility in the various stages of its use. Since the conditions are very different for the different uses, the assessment calls for a variety of different leaching conditions. The pH dependence test is used to cover important differences in pH environment to which the materials are exposed to as well as for an assessment of the buffering capacity of the material. Synthetic aggregate features a low buffer capacity, which makes it sensitive to externally imposed pH conditions. Utilisation and storage exposed to acidic conditions needs to be avoided. The results of the pH dependence test and column leaching test are mutually consistent. The CEN TC 154 method appears to provide systematically low values due to the arbitrary selection of test conditions. Synthetic aggregate studied to date will not adversely affect the concrete in its service life. The main issue for aggregate use is the recycling and the "end of life" condition, when the material becomes construction debris. Not metals, but oxyanions, such as Cr VI and Mo are most relevant under these conditions. A concise test has been applied to assess crucial aspects of leaching for different production mixes.

  1. Impact of transition metal on nitrogen retention and activity of iron-nitrogen-carbon oxygen reduction catalysts.

    PubMed

    Ganesan, Selvarani; Leonard, Nathaniel; Barton, Scott Calabrese

    2014-03-14

    Iron based nitrogen doped carbon (FeNC) catalysts are synthesized by high-pressure pyrolysis of carbon and melamine with varying amounts of iron acetate in a closed, constant-volume reactor. The optimum nominal amount of Fe (1.2 wt%) in FeNC catalysts is established through oxygen reduction reaction (ORR) polarization. Since the quantity of iron used in FeNCs is very small, the amount of Fe retained in FeNC catalysts after leaching is determined by UV-VIS spectroscopy. As nitrogen is considered to be a component of active sites, the amount of bulk and surface nitrogen retention in FeNC catalysts are measured using elemental analysis and X-ray photoelectron spectroscopy, respectively. It is found that increasing nominal Fe content in FeNC catalysts leads to a decreased level of nitrogen retention. Thermogravimetric analysis demonstrates that increasing nominal Fe content leads to increased weight loss during pyrolysis, particularly at high temperatures. Catalysts are also prepared in the absence of iron source, and with iron removed by washing with hot aqua regia post-pyrolysis. FeNC catalysts prepared with no Fe show high retained nitrogen content but poor ORR activity, and aqua regia washed catalysts demonstrate similar activity to Fe-free catalysts, indicating that Fe is an active site component.

  2. Implementation of the Leaching Environmental Assessment Framework

    EPA Science Inventory

    New leaching tests are available in the U.S. for developing more accurate source terms for use in fate and transport models. For beneficial use or disposal, the use of the leaching environmental assessment framework (LEAF) will provide leaching results that reflect field condit...

  3. Management practices for minimising nitrate leaching after ploughing temporary leguminous pastures in Canterbury, New Zealand

    NASA Astrophysics Data System (ADS)

    Francis, G. S.

    1995-12-01

    Winter leaching losses of nitrate following the ploughing of temporary leguminous pastures in late summer or early autumn are a major concern in mixed cropping rotations on the Canterbury Plains of New Zealand. Field experiments showed that pastures ploughed in early autumn (March) and left fallow accumulated 107-142 kg ha -1 N of mineral-N in the soil profile by the start of winter, with 72-106 kg ha -1 N lost through leaching in the first winter. Delaying the ploughing of pasture until late autumn (May) reduced the accumulation of mineral-N to 42-120 kg ha -1 N and the leaching loss to 8-52 kg ha -1 N. In situations where early cultivation cannot be avoided, growing winter cover crops or using the nitrification inhibitor dicyandiamide (DCD) both have the potential to reduce leaching compared with fallow soil. DCD increased the amount of mineral-N present in the soil as ammonium and reduced leaching losses by 25-50% without affecting the yield of the following spring wheat crop. Cover crops only reduced leaching losses (by up to 60%) when they were sown early in the autumn and they had taken up considerable amounts of soil mineral-N before drainage occurred. When cover crops were grazed before incorporation in spring, there was an increased risk of leaching from urine patch areas. If residues were incorporated without grazing, however, the yield of the following spring wheat crop was depressed by 20-30% due to extensive net N immobilization during decomposition of the residues. In Canterbury conditions, the most reliable way to minimise N leaching losses is to delay the ploughing of pasture for as long as possible in autumn or winter. Where pastures are ploughed early, the relative effectiveness of using DCD or growing winter cover crops varies mainly in relation to rainfall distribution.

  4. Differential leaching of nutrients from soluble vs. controlled-release fertilizers

    NASA Astrophysics Data System (ADS)

    Alva, Ashok K.

    1992-11-01

    Extremely sandy soils and poorly distributed high annual rainfall in the state of Florida contribute to significant leaching losses of nutrients from routine fertilization practices. A leaching column experiment was conducted to evaluate the leaching losses of nutrients when using currently available N, P, K blend fertilizers for young citrus tree fertilization. Fertilizer blends included NH4NO3, Ca(NO3)2, IBDU, IBDU plus Escote, Nutralene, Osmocote, and Meister. Following leaching of 1000 ml of water through soil columns, which simulates leaching conditions with 26 cm of rainfall, the amount of NO3 and NH4 recovered in the leachate from soil columns amended with an NH4NO3 blend accounted for 37% and 88% of the respective nutrients contained in the quantity of blend per column. The corresponding values for soil columns amended with a Ca(NO3)2 blend were 48% and 100%. Leraching losses of both NO3 (<3%) and NH4 (<4%) were drastically decreased when using controlled-release fertilizers. The recoveries of P and K in 1000 ml of leachate were 1.3% and 8%, respectively, of the nutrients added as Osmocote, which contained coated P and K sources. In the case of the rest of fertilizer blends, the recoveries of P and K in 1000 ml of leachate were as high as 52%-100% and 28%-100%, respectively. Therefore, controlled-release technology offers an important capability for minimizing leaching losses of nutrients.

  5. ArcNEMO, a spatially distributed nutrient emission model developed in Python to quantify losses of nitrogen and phosphorous from agriculture to surface waters

    NASA Astrophysics Data System (ADS)

    Van Opstal, Mattias; Tits, Mia; Beckers, Veronique; Batelaan, Okke; Van Orshoven, Jos; Elsen, Annemie; Diels, Jan; D'heygere, Tom; Van Hoof, Kor

    2014-05-01

    Pollution of surface water bodies with nitrogen (N) and phosphorous (P) from agricultural sources is a major problem in areas with intensive agriculture in Europe. The Flemish Environment Agency requires information on how spatially explicit policy measures on manure and fertilizer use, and changes in land use and soil management affect the N and P concentration in the surface waters in the region of Flanders, Belgium. To assist in this, a new spatially distributed, mechanistic nutrient emission model was developed in the open-source language Python. The model is called ArcNEMO (Nutrient Emission MOdel). The model is fully integrated in ArcGIS, but could be easily adapted to work with open-source GIS software. In Flanders, detailed information is available each year on the delineation of each agricultural parcel and the crops grown on them. Parcels are linked to farms, and for each farm yearly manure and fertilizer use is available. To take full advantage of this information and to be able to simulate nutrient losses to the high-density surface water network, the model makes use of grid cells of 50 by 50m. A fertilizer allocation model was developed to calculate from the yearly parcel and farm data the fertilizer and manure input per grid cell for further use in the ArcNEMO-model. The model architecture was chosen such that the model can be used to simulate spatially explicit monthly discharge and losses of N and P to the surface water for the whole of Flanders (13,500 km²) over periods of 10-20 years. The extended time period is necessary because residence times in groundwater and the rates of organic matter turnover imply that water quality reacts slowly to changes of land use and fertilization practices. Vertical water flow and nutrient transport in the unsaturated zone are described per grid cell using a cascading bucket-type model with daily time steps. Groundwater flow is described by solving the 2D-groundwater flow equation using an explicit numerical

  6. Enteric and manure-derived methane and nitrogen emissions as well as metabolic energy losses in cows fed balanced diets based on maize, barley or grass hay.

    PubMed

    Klevenhusen, F; Kreuzer, M; Soliva, C R

    2011-03-01

    Ruminant husbandry constitutes the most important source of anthropogenic methane (CH4). In addition to enteric (animal-derived) CH4, excreta are another source of CH4, especially when stored anaerobically. Increasing the proportion of dietary concentrate is often considered as the primary CH4 mitigation option. However, it is unclear whether this is still valid when diets to be compared are energy-balanced. In addition, non-structural carbohydrates and side effects on nitrogen (N) emissions may be important. In this experiment, diet types representing either forage-only or mixed diets were examined for their effects on CH4 and N emissions from animals and their slurries in 18 lactating cows. Apart from a hay-only diet, treatments included two mixed diets consisting of maize stover, pelleted whole maize plants and gluten or barley straw and grain and soy bean meal. The diets were balanced in crude protein and net energy for lactation. After adaptation, data and samples were collected for 8 days including a 2-day CH4 measurement in respiratory chambers. Faeces and urine, combined proportionately according to excretion, were used to determine slurry-derived CH4 and N emissions. Slurry was stored for 15 weeks at either 14°C or 27°C, and temperatures were classified as 'cool' and 'warm', respectively. The low-starch hay-only diet had high organic matter and fibre digestibility and proved to be equally effective on the cows' performance as mixed diets. The enteric CH4 formation remained unaffected by the diet except when related to digested fibre. In this case emission was lowest with the hay-only diet (61 v. 88 to 101 g CH4/kg digested NDF). Feeding the hay diet resulted in the highest slurry-CH4 production after 7 weeks of storage at 14°C and 27°C, and after 15 weeks at 14°C. CH4 emissions were, in general, about 10-fold higher at 27°C compared with 14°C but only after 15 weeks of storage. Urinary N losses were highest with the barley diet and lowest with the

  7. Lead removal via soil washing and leaching

    NASA Astrophysics Data System (ADS)

    Lin, H. K.; Man, X. D.; Walsh, D. E.

    2001-12-01

    A soil washing and leaching process was tested for removing lead from soils. A soil-washing circuit, including size and gravity separations, was employed to remove the coarse metallic lead particles, while the leaching was applied to remove fine metallic lead particles and other lead species. The soil-washing tests proved that the metallic lead particles larger than 0.15 mm (100 mesh) could be effectively removed. The sodium-chloride-based leaching solution with ferric chloride or sodium hypochlorite as oxidants was adopted in the leaching. The leaching experimental results indicated that under the pH of 2 and Eh of 1,300 mV, the metallic lead particles smaller than 0.15 mm and other lead species can be dissolved in the leaching solution within 60 minutes.

  8. URANIUM LEACHING AND RECOVERY PROCESS

    DOEpatents

    McClaine, L.A.

    1959-08-18

    A process is described for recovering uranium from carbonate leach solutions by precipitating uranium as a mixed oxidation state compound. Uranium is recovered by adding a quadrivalent uranium carbon;te solution to the carbonate solution, adjusting the pH to 13 or greater, and precipitating the uranium as a filterable mixed oxidation state compound. In the event vanadium occurs with the uranium, the vanadium is unaffected by the uranium precipitation step and remains in the carbonate solution. The uranium-free solution is electrolyzed in the cathode compartment of a mercury cathode diaphragm cell to reduce and precipitate the vanadium.

  9. RELATIVE LEACHING AND AQUATIC TOXICITY OF PRESSURE-TREATED WOOD PRODUCTS USING BATCH LEACHING TESTS

    EPA Science Inventory

    Samples of southern yellow pine dimensional lumber, each treated with one of five different waterborne chemical preservatives, were leached using 18-hour batch leaching tests. The wood preservatives included chromated copper arsenate (CCA), alkaline copper quaternary (ACQ), coppe...

  10. A New Generation of Leaching Tests – The Leaching Environmental Assessment Framework

    EPA Science Inventory

    Provides an overview of newly released leaching tests that provide a more accurate source term when estimating environmental release of metals and other constituents of potential concern (COPCs). The Leaching Environmental Assessment Framework (LEAF) methods have been (1) develo...

  11. [Effects of biochar on soil nutrients leaching and potential mechanisms: A review].

    PubMed

    Liu, Yu-xue; Lyu, Hao-hao; Shi, Yan; Wang, Yao-feng; Zhong, Zhe-ke; Yang, Sheng-mao

    2015-01-01

    Controlling soil nutrient leaching in farmland ecosystems has been a hotspot in the research field of agricultural environment. Biochar has its unique physical and chemical properties, playing a significant role in enhancing soil carbon storage, improving soil quality and increasing crop yield. As a kind of new exogenous material, biochar has the potential in impacting soil nutrient cycling directly or indirectly, and has profound influences on soil nutrient leaching. This paper analyzed the intrinsic factors affecting how biochar affects soil nutrient leaching, such as the physical and chemical properties of biochar, and the interaction between biochar and soil organisms. Then the latest literatures regarding the external factors, including biochar application rates, soil types, depth of soil layer, fertilization conditions and temporal dynamics, through which biochar influences soil nutrient (especially nitrogen and phosphorus) leaching were reviewed. On that basis, four related action mechanisms were clarified, including direct adsorption of nutrients by biochar due to its micropore structure or surface charge, influencing nutrient leaching through increasing soil water- holding capacity, influencing nutrient cycling through the interaction with soil microbes, and preferential transport of absorbed nutrients by fine biochar particles. At last future research directions for better understanding the interactions between biochar and nutrient leaching in the soil were proposed.

  12. Sulphur in char and char desulphurization by acid leaching and hydropyrolysis

    USGS Publications Warehouse

    Chou, I.-Ming; Loffredo, D.M.

    1985-01-01

    Sulphur compounds volatilized during pyrolysis of acid-leached char were measured to determine characteristics of char desulphurization reactions. Pyrolysis of char in a hydrogen atmosphere (hydropyrolysis) produced a much higher concentration of thiophenic organics compared with that produced during pyrolysis in a nitrogen atmosphere. Hydrogen sulphide gas evolution, at progressively increasing pyrolysis temperature in a helium atmosphere, was measured on five char samples: untreated char, hydrochloric acid-leached char, and three model chars: a demineralized char and two demineralized chars incorporated with sulphur via reactions with elemental sulphur. Hydrogen sulphide gas evolution in untreated char and acid-leached char was found to peak in three temperature regions; the maxima are thought to relate to sulphur in different bonding environments. The amounts of hydrogen sulphide volatilized were much higher for acid-leached char than for untreated char. The gas evolved from each of the remaining three samples showed a single peak region corresponding closely to one of the three peak regions observed for the first two chars. The results of this study indicate that elemental sulphur was produced during hydrochloric acid leaching of the untreated char and suggested that the improved rate of desulphurization observed in the char that had been acid-leached before hydropyrolysis was due in part to the conversion of strongly bound mineral sulphur forms to more weakly bound sulphur forms that are predominantly elemental sulphur in character, and are more easily removed by hydrogen. ?? 1985.

  13. Consumptive use and resulting leach-field water budget of a mountain residence

    USGS Publications Warehouse

    Stannard, David; Paul, William T.; Laws, Roy; Poeter, Eileen P.

    2010-01-01

    Consumptive use of water in a dispersed rural community has important implications for maximum housing density and its effects on sustainability of groundwater withdrawals. Recent rapid growth in Colorado, USA has stressed groundwater supplies in some areas, thereby increasing scrutiny of approximate methods developed there more than 30 years ago to estimate consumptive use that are still used today. A foothills residence was studied during a 2-year period to estimate direct and indirect water losses. Direct losses are those from evaporation inside the home, plus any outdoor use. Indirect loss is evapotranspiration (ET) from the residential leach-field in excess of ET from the immediately surrounding terrain. Direct losses were 18.7% of water supply to the home, substantially larger than estimated historically in Colorado. A new approach was developed to estimate indirect loss, using chamber methods together with the Penman–Monteith model. Indirect loss was only 0.9% of water supply, but this value probably was anomalously low due to a recurring leach-field malfunction. Resulting drainage beneath the leach-field was 80.4% of water supply. Guidelines are given to apply the same methodology at other sites and combine results with a survey of leach-fields in an area to obtain more realistic average values of ET losses.

  14. High retention of (15) N-labeled nitrogen deposition in a nitrogen saturated old-growth tropical forest.

    PubMed

    Gurmesa, Geshere Abdisa; Lu, Xiankai; Gundersen, Per; Mao, Qinggong; Zhou, Kaijun; Fang, Yunting; Mo, Jiangming

    2016-11-01

    The effects of increased reactive nitrogen (N) deposition in forests depend largely on its fate in the ecosystems. However, our knowledge on the fates of deposited N in tropical forest ecosystems and its retention mechanisms is limited. Here, we report the results from the first whole ecosystem (15) N labeling experiment performed in a N-rich old-growth tropical forest in southern China. We added (15) N tracer monthly as (15) NH4(15) NO3 for 1 year to control plots and to N-fertilized plots (N-plots, receiving additions of 50 kg N ha(-1)  yr(-1) for 10 years). Tracer recoveries in major ecosystem compartments were quantified 4 months after the last addition. Tracer recoveries in soil solution were monitored monthly to quantify leaching losses. Total tracer recovery in plant and soil (N retention) in the control plots was 72% and similar to those observed in temperate forests. The retention decreased to 52% in the N-plots. Soil was the dominant sink, retaining 37% and 28% of the labeled N input in the control and N-plots, respectively. Leaching below 20 cm was 50 kg N ha(-1)  yr(-1) in the control plots and was close to the N input (51 kg N ha(-1)  yr(-1) ), indicating N saturation of the top soil. Nitrogen addition increased N leaching to 73 kg N ha(-1)  yr(-1) . However, of these only 7 and 23 kg N ha(-1)  yr(-1) in the control and N-plots, respectively, originated from the labeled N input. Our findings indicate that deposited N, like in temperate forests, is largely incorporated into plant and soil pools in the short term, although the forest is N-saturated, but high cycling rates may later release the N for leaching and/or gaseous loss. Thus, N cycling rates rather than short-term N retention represent the main difference between temperate forests and the studied tropical forest.

  15. Monitoring of water and nitrate leaching in an almond orchard

    NASA Astrophysics Data System (ADS)

    Kandelous, M. M.; Moradi, A. B.; Brown, P.; Hopmans, J. W.

    2013-12-01

    The quality of groundwater is specifically vulnerable in irrigated agricultural lands such as in California and many other (semi-) arid regions of the world. The regular application of nitrogen fertilizers with irrigation water is likely responsible for the increase in nitrate concentrations of groundwater resources such as in CA's main agricultural areas in the Salinas Valley and the Tulare Lake Basin. Since groundwater contamination regulations are going to be implemented, improved fertigation practices may become an essential part of CA farming operations. Therefore, we conducted a field study in an almond orchard located in Lost Hills, CA which provides critical information on the movement of water and nutrients through the soil under variable soil moisture conditions. Water balance and Darcy equation were two approaches used to estimate the leaching in this study. Given the amount of applied irrigation water using flowmeter, water lost through evapotranspiration measured by Eddy-Covariance tower, changes in soil water storage using neutron probe data, and precipitation data provided by a nearby CIMIS station, we applied water balance to estimate the amount of leaching water. In the other hand, coupled deep tensiometers were used to calculate the head gradient below the root zone, thereby estimating the leaching flux with Darcy equation for known hydraulic conductivity of layer between two tensiometers. Although, the cumulative amount of leaching estimated by water balance were in the same order of magnitude as what was estimated using Darcy method, the uncertainties and different cumulative trend observed in each method suggest further evaluation of collected data and also looking for an alternative method which could reduce the observed uncertainty.

  16. Production of Biomass Crops Using Biowastes on Low-Fertility Soil: 2. Effect of Biowastes on Nitrogen Transformation Processes.

    PubMed

    Esperschuetz, J; Bulman, S; Anderson, C; Lense, O; Horswell, J; Dickinson, N; Robinson, B H

    2016-11-01

    Increasing production of biowastes, particularly biosolids (sewage sludge), requires sustainable management strategies for their disposal. Biosolids can contain high concentrations of nutrients; hence, land application can have positive effects on plant growth and soil fertility, especially when applied to degraded soils. However, high rates of biosolids application may result in excessive nitrogen (N) leaching, which can be mitigated by blending biosolids with other biowastes, such as sawdust. We aimed to determine the effects of biosolids and sawdust on growth and N uptake by sorghum, rapeseed, and ryegrass as well as N losses via leaching. Plants were grown in a greenhouse over a 5-mo period in a low-fertility soil amended with biosolids (1250 kg N ha), biosolids-sawdust (0.5:1), or urea (200 kg N ha). Urea application increased biomass production of sorghum and ryegrass but proved insufficient for rapeseed on low-fertility soil. Biosolids application increased plant N concentrations in ryegrass and rapeseed and increased N uptake into the seeds of sorghum, increasing seed quality. Biosolids application did result in lower N leaching compared with urea, irrespective of plant species, and N leaching was unaffected by mixing the biosolids with sawdust. There was an indication of biological nitrification inhibition in the rhizosphere of sorghum. Rapeseed had similar growth and N uptake into biomass in biosolids and biosolids-sawdust treatments and hence was the most promising species with regard to recycling fresh sawdust in combination with high rates of biosolids on low-fertility soil.

  17. Wildfire effects on soil nutrients and leaching in a tahoe basin watershed.

    PubMed

    Murphy, J D; Johnson, D W; Miller, W W; Walker, R F; Carroll, E F; Blank, R R

    2006-01-01

    A wildfire burned through a previously sampled research site, allowing pre- and post-burn measurements of the forest floor, soils, and soil leaching near Lake Tahoe, Nevada. Fire and post-fire erosion caused large and statistically significant (P < or = 0.05) losses of C, N, P, S, Ca, and Mg from the forest floor. There were no statistically significant effects on mineral soils aside from a decrease in total N in the surface (A11) horizon, an increase in pH in the A11 horizon, and increases in water-extractable SO4(2-) in the A11 and A12 horizons. Burning caused consistent but nonsignificant increases in exchangeable Ca2+ in most horizons, but no consistent or statistically significant effects on exchangeable K+ or Mg2+, or on Bray-, bicarbonate-, or water-extractable P concentrations. Before the burn, there were no significant differences in leaching, but during the first winter after the fire, soil solution concentrations of NH4+, NO3-, ortho-P, and (especially) SO4(2-) were elevated in the burned area, and resin lysimeters showed significant increases in the leaching of NH4+ and mineral N. The leaching losses of mineral N were much smaller than the losses from the forest floor and A11 horizons, however. We conclude that the major short-term effects of wildfire were on leaching whereas the major long-term effect was the loss of N from the forest floor and soil during the fire.

  18. Carbon leaching from tropical peat soils and consequences for carbon balances

    NASA Astrophysics Data System (ADS)

    Rixen, Tim; Baum, Antje; Wit, Francisca; Samiaji, Joko

    2016-07-01

    Drainage and deforestation turned Southeast (SE) Asian peat soils into a globally important CO2 source, because both processes accelerate peat decomposition. Carbon losses through soil leaching have so far not been quantified and the underlying processes have hardly been studied. In this study, we use results derived from nine expeditions to six Sumatran rivers and a mixing model to determine leaching processes in tropical peat soils, which are heavily disturbed by drainage and deforestation. Here we show that a reduced evapotranspiration and the resulting increased freshwater discharge in addition to the supply of labile leaf litter produced by re-growing secondary forests increase leaching of carbon by ~200%. Enhanced freshwater fluxes and leaching of labile leaf litter from secondary vegetation appear to contribute 38% and 62% to the total increase, respectively. Decomposition of leached labile DOC can lead to hypoxic conditions in rivers draining disturbed peatlands. Leaching of the more refractory DOC from peat is an irrecoverable loss of soil that threatens the stability of peat-fringed coasts in SE Asia.

  19. Soil column leaching of pesticides.

    PubMed

    Katagi, Toshiyuki

    2013-01-01

    In this review, I address the practical and theoretical aspects of pesticide soil mobility.I also address the methods used to measure mobility, and the factors that influence it, and I summarize the data that have been published on the column leaching of pesticides.Pesticides that enter the unsaturated soil profile are transported downwards by the water flux, and are adsorbed, desorbed, and/or degraded as they pass through the soil. The rate of passage of a pesticide through the soil depends on the properties of the pesticide, the properties of the soil and the prevailing environmental conditions.Because large amounts of many different pesticides are used around the world, they and their degradates may sometimes contaminate groundwater at unacceptable levels.It is for this reason that assessing the transport behavior and soil mobility of pesticides before they are sold into commerce is important and is one indispensable element that regulators use to assess probable pesticide safety. Both elementary soil column leaching and sophisticated outdoor lysimeter studies are performed to measure the leaching potential for pesticides; the latter approach more reliably reflects probable field behavior, but the former is useful to initially profile a pesticide for soil mobility potential.Soil is physically heterogeneous. The structure of soil varies both vertically and laterally, and this variability affects the complex flow of water through the soil profile, making it difficult to predict with accuracy. In addition, macropores exist in soils and further add to the complexity of how water flow occurs. The degree to which soil is tilled, the density of vegetation on the surface, and the type and amounts of organic soil amendments that are added to soil further affect the movement rate of water through soil, the character of soil adsorption sites and the microbial populations that exist in the soil. Parameters that most influence the rate of pesticide mobility in soil are

  20. [Effects of nitrogen management on maize nitrogen utilization and residual nitrate nitrogen in soil under maize/soybean and maize/sweet potato relay strip intercropping systems].

    PubMed

    Wang, Xiao-Chun; Yang, Wen-Yu; Deng, Xiao-Yan; Zhang, Qun; Yong, Tai-Wen; Liu, Wei-Guo; Yang, Feng; Mao, Shu-Ming

    2014-10-01

    A large amount of nitrogen (N) fertilizers poured into the fields severely pollute the environment. Reasonable application of N fertilizer has always been the research hotpot. The effects of N management on maize N utilization and residual nitrate N in soil under maize/soybean and maize/ sweet potato relay strip intercropping systems were reported in a field experiment in southwest China. It was found that maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/soybean relay strip intercropping were increased by 6.1%, 5.4%, 4.3%, and 15.1% than under maize/sweet potato with an increase of 22.6% for maize yield after sustainable growing of maize/soybean intercropping system. Nitrate N accumulation in the 0-60 cm soil layer was 12.9% higher under maize/soybean intercropping than under maize/sweet potato intercropping. However, nitrate N concentration in the 60-120 cm soil layer when intercropped with soybean decreased by 10.3% than when intercropped with sweet potato, indicating a decrease of N leaching loss. Increasing of N application rate enhanced N accumulation of maize and decreased N use efficiency and significantly increased nitrate concentration in the soil profile except in the 60-100 cm soil layer, where no significant difference was observed with nitrogen application rate at 0 to 270 kg · hm(-2). Further application of N fertilizer significantly enhanced nitrate leaching loss. Postponing N application increased nitrate accumulation in the 60-100 cm soil layer. The results suggested that N application rates and ratio of base to top dressing had different influences on maize N concentration and nitrate N between maize/soybean and maize/sweet potato intercropping. Maize N concentration in the late growing stage, N harvest index and N use efficiency under maize/soybean intercropping increased (with N application rate at 180-270 kg · hm(-2) and ratio of base to top dressing = 3:2:5) and

  1. A regional assessment of the cost and effectiveness of mitigation measures for reducing nutrient losses to water and greenhouse gas emissions to air from pastoral farms.

    PubMed

    Vibart, Ronaldo; Vogeler, Iris; Dennis, Samuel; Kaye-Blake, William; Monaghan, Ross; Burggraaf, Vicki; Beautrais, Josef; Mackay, Alec

    2015-06-01

    Using a novel approach that links geospatial land resource information with individual farm-scale simulation, we conducted a regional assessment of nitrogen (N) and phosphorous (P) losses to water and greenhouse gas (GHG) emissions to air from the predominant mix of pastoral industries in Southland, New Zealand. An evaluation of the cost-effectiveness of several nutrient loss mitigation strategies applied at the farm-scale, set primarily for reducing N and P losses and grouped by capital cost and potential ease of adoption, followed an initial baseline assessment. Grouped nutrient loss mitigation strategies were applied on an additive basis on the assumption of full adoption, and were broadly identified as 'improved nutrient management' (M1), 'improved animal productivity' (M2), and 'restricted grazing' (M3). Estimated annual nitrate-N leaching losses occurring under representative baseline sheep and beef (cattle) farms, and representative baseline dairy farms for the region were 10 ± 2 and 32 ± 6 kg N/ha (mean ± standard deviation), respectively. Both sheep and beef and dairy farms were responsive to N leaching loss mitigation strategies in M1, at a low cost per kg N-loss mitigated. Only dairy farms were responsive to N leaching loss abatement from adopting M2, at no additional cost per kg N-loss mitigated. Dairy farms were also responsive to N leaching loss abatement from adopting M3, but this reduction came at a greater cost per kg N-loss mitigated. Only dairy farms were responsive to P-loss mitigation strategies, in particular by adopting M1. Only dairy farms were responsive to GHG abatement; greater abatement was achieved by the most intensified dairy farm system simulated. Overall, M1 provided for high levels of regional scale N- and P-loss abatement at a low cost per farm without affecting overall farm production, M2 provided additional N-loss abatement but only marginal P-loss abatement, whereas M3 provided the greatest N-loss abatement, but

  2. Leaching Tc-99 from SRP glass in simulated tuff and salt groundwaters

    SciTech Connect

    Bibler, N E; Jurgensen, A R

    1987-01-01

    Results of leach tests with Tc-99 doped SRP borosilicate waste glass are presented. The glass was prepared by melting a mixture of SRP 165 powdered frit doped with a carrier free solution of Tc-99 at 1150{sup 0}C. Dissolution of portions of the resulting glass indicated that the Tc-99 was distributed homogeneously throughout the glass. Static leach tests up to 90 days were performed at 90{sup 0}C in J-13 tuff groundwater or WIPP brine A at a SA/V of 100m{sup -1}. Normalized mass losses were calculated for Tc-99 as well as all the major elements in the glass. Results indicated that under ambient oxidizing conditions Tc-99 leached no faster than the glass-forming elements of the glass. In J-13 water, Tc-99 leached congruently with B. In WIPP brine A, it leached congruently with Si. Leach rates for Li were higher in both groundwaters, probably due to a contribution from an ion exchange mechanism. Leach tests were performed under reducing conditions in J-13 water by adding Zn/Hg amalgam to the leachate. In these tests the pH increased significantly, probably because of the reaction of the amalgam with the water. In a 21-day test, the pH increased to 13 and leach rates for the glass were very high. Even though there was signifcant dissolution of the glass, the normalized mass loss based on Tc-99 was only 0.02g/m{sup 2}. This result and the fact that reducing conditions at normal pH values do not significantly affect the dissolution of the glass, indicate that the low concentrations for Tc-99 obtained under reducing conditions are due to is solubility and not due to an increased durability of the glass. 14 refs., 2 figs., 5 tabs.

  3. Mechanisms of nitrogen retention in forest ecosystems - A field experiment

    NASA Technical Reports Server (NTRS)

    Vitousek, P. M.; Matson, P. A.

    1984-01-01

    Intensive forest management led to elevated losses of nitrogen from a recently harvested loblolly pine plantation in North Carolina. Measurements of nitrogen-15 retention in the field demonstrated that microbial uptake of nitrogen during the decomposition of residual organic material was the most important process retaining nitrogen. Management practices that remove this material cause increased losses of nitrogen to aquatic ecosystems and the atmosphere.

  4. Leaching adapted for metals in soil

    SciTech Connect

    Fristad, W.E.; Weerts, K.E.

    1993-05-01

    The technical hurdle in metal leaching is coupling a leaching process, which effectively removes the contaminant metals from the soil, with a recovery process that isolates the metal in a form suitable for disposal or reuse. Problems associated with this process are described.

  5. LEACHING OF METALS FROM MINERAL PROCESSING WASTE

    EPA Science Inventory

    The purpose of this project is to test the leaching of Mineral processing Waste (MPW) contaminated with heavy metals using scientifically defendable leaching tests other than TCLP. Past experience and literature have shown that TCLP underestiates the levels of metals such as oxoa...

  6. Atrazine leaching from biochar-amended soils.

    PubMed

    Delwiche, Kyle B; Lehmann, Johannes; Walter, M Todd

    2014-01-01

    The herbicide atrazine is used extensively throughout the United States, and is a widespread groundwater and surface water contaminant. Biochar has been shown to strongly sorb organic compounds and could be used to reduce atrazine leaching. We used lab and field experiments to determine biochar impacts on atrazine leaching under increasingly heterogeneous soil conditions. Application of pine chip biochar (commercially pyrolyzed between 300 and 550 °C) reduced cumulative atrazine leaching by 52% in homogenized (packed) soil columns (p=0.0298). Biochar additions in undisturbed soil columns did not significantly (p>0.05) reduce atrazine leaching. Mean peak groundwater atrazine concentrations were 53% lower in a field experiment after additions of 10 t ha(-1) acidified biochar (p=0.0056) relative to no biochar additions. Equivalent peat applications by dry mass had no effect on atrazine leaching. Plots receiving a peat-biochar mixture showed no reduction, suggesting that the peat organic matter may compete with atrazine for biochar sorption sites. Several individual measurement values outside the 99% confidence interval in perched groundwater concentrations indicate that macropore structure could contribute to rare, large leaching events that are not effectively reduced by biochar. We conclude that biochar application has the potential to decrease peak atrazine leaching, but heterogeneous soil conditions, especially preferential flow paths, may reduce this impact. Long-term atrazine leaching reductions are also uncertain.

  7. LEACHING OF METALS FROM MINERAL PROCESSING WASTE

    EPA Science Inventory

    The purpose of this project is to test the leaching of Mineral Processing Waste (MPW) contaminated with heavy metals using scientifically defendable leaching tests other than TCLP. Past experience and literature have shown that TCLP underestimates the levels of metals such as oxo...

  8. Coatings to reduce wood preservative leaching.

    PubMed

    Nejad, Mojgan; Cooper, Paul

    2010-08-15

    The efficiency of semitransparent penetrating stains to reduce leaching of wood preservative components was evaluated. Five commercial wood deck finishes were applied to untreated and chromated copper arsenate (CCA), alkaline copper quat (ACQ), and copper azole (CA) treated wood, and leachates were collected and analyzed during 3 years of natural weathering exposure in Toronto, Canada. All stains evaluated effectively reduced the cumulative leaching of all inorganic preservative components by about 60% on average. Although most coatings showed significant film degradation starting around 12 months, the reduced leaching persisted even after 3 years. This suggests that temporary protection of wood with a coating during the early stages of use resulted in long-term reduction in preservative leaching potential. A two-week screening leaching test was able to predict the long-term leaching performance of different coatings reasonably well. Cured coating glass transition temperature (Tg) and liquid coating viscosity were the most important variables affecting a leaching prediction model. To effectively reduce leaching of preservative components from treated wood, coatings should have Tg low enough to withstand stresses caused by freezing in winter and have adequate viscosity to form a barrier film layer on the wood surface.

  9. Properties of Leach-Flessas-Gorringe polynomials

    NASA Astrophysics Data System (ADS)

    Pursey, D. L.

    1990-09-01

    A generating function is obtained for the polynomials recently introduced by Leach, Flessas, and Gorringe [J. Math. Phys. 30, 406 (1989)], and is then used to relate the Leach-Flessas-Gorringe (or LFG) polynomials to Hermite polynomials. The generating function is also used to express a number of integrals involving the LFG polynomials as finite sums of parabolic cylinder functions.

  10. Lead Isotope Systematics of Leached Meteoritic Minerals

    NASA Astrophysics Data System (ADS)

    Tera, F.; Carlson, R. W.; Boctor, N. Z.

    1996-03-01

    The generally low Pb concentrations in meteorites coupled with the pervasiveness of Pb on earth, often requires acid-leaching of meteoritic matter in order to remove the terrestrial contamination. Besides discussing this application, we draw attention to some "side effects" of leaching on the Pb isotope systematics.

  11. Relative leaching and aquatic toxicity of pressure-treated wood products using batch leaching tests.

    PubMed

    Stook, Kristin; Tolaymat, Thabet; Ward, Marnie; Dubey, Brajesh; Townsend, Timothy; Solo-Gabriele, Helena; Bitton, Gabriel

    2005-01-01

    Size-reduced samples of southern yellow pine dimensional lumber, each treated with one of five different waterborne chemical preservatives, were leached using 18-h batch leaching tests. The wood preservatives included chromated copper arsenate (CCA), alkaline copper quaternary, copper boron azole, copper citrate, and copper dimethyldithiocarbamate. An unpreserved wood sample was tested as well. The batch leaching tests followed methodology prescribed in the U.S. Environmental Protection Agency toxicity characteristic leaching procedure (TCLP). The wood samples were first size-reduced and then leached using four different leaching solutions (synthetic landfill leachate, synthetic rainwater, deionized water, and synthetic seawater). CCA-treated wood leached greater concentrations of arsenic and copper relative to chromium, with copper leaching more with the TCLP and synthetic seawater. Copper leached at greater concentrations from the arsenic-free preservatives relative to CCA. Arsenic leached from CCA-treated wood at concentrations above the U.S. federal toxicity characteristic limit (5 mg/L). All of the arsenic-free alternatives displayed a greater degree of aquatic toxicity compared to CCA. Invertebrate and algal assays were more sensitive than Microtox. Examination of the relative leaching of the preservative compounds indicated that the arsenic-free preservatives were advantageous over CCA with respect to waste disposal and soil contamination issues but potentially posed a greater risk to aquatic ecosystems.

  12. Lead leaching from pressure cookers.

    PubMed

    Raghunath, R; Nambi, K S

    1998-12-11

    Leachability of lead by tap water and tamarind solution from Indian pressure cookers while cooking with and without a safety valve is studied. Lead contamination of food by cookers is not very high when compared to the daily intake of lead from various food items consumed by the Indian community. However, looking at the very wide range of lead levels leached from various brands of pressure cookers, it certainly seems possible to keep the lead contamination to the minimum by proper choice of the materials used in the manufacture of these pressure cookers. The rubber gasket, which is a very important component of any pressure cooker, contains the maximum lead concentration; the safety valve is another important source leading to lead contamination of cooked food.

  13. Dynamic leaching test of personal computer components.

    PubMed

    Li, Yadong; Richardson, Jay B; Niu, Xiaojun; Jackson, Ollie J; Laster, Jeremy D; Walker, Aaron K

    2009-11-15

    A dynamic leaching test (DLT) was developed and used to evaluate the leaching of toxic substances for electronic waste in the environment. The major components in personal computers (PCs) including motherboards, hard disc drives, floppy disc drives, and compact disc drives were tested. The tests lasted for 2 years for motherboards and 1.5 year for the disc drives. The extraction fluids for the standard toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) were used as the DLT leaching solutions. A total of 18 elements including Ag, Al, As, Au, Ba, Be, Cd, Cr, Cu, Fe, Ga, Ni, Pd, Pb, Sb, Se, Sn, and Zn were analyzed in the DLT leachates. Only Al, Cu, Fe, Ni, Pb, and Zn were commonly found in the DLT leachates of the PC components. Their leaching levels were much higher in TCLP extraction fluid than in SPLP extraction fluid. The toxic heavy metal Pb was found to continuously leach out of the components over the entire test periods. The cumulative amounts of Pb leached out of the motherboards in TCLP extraction fluid reached 2.0 g per motherboard over the 2-year test period, and that in SPLP extraction fluid were 75-90% less. The leaching rates or levels of Pb were largely affected by the content of galvanized steel in the PC components. The higher was the steel content, the lower the Pb leaching rate would be. The findings suggest that the obsolete PCs disposed of in landfills or discarded in the environment continuously release Pb for years when subjected to landfill leachate or rains.

  14. Albert Behnke: nitrogen narcosis.

    PubMed

    Grover, Casey A; Grover, David H

    2014-02-01

    As early as 1826, divers diving to great depths noted that descent often resulted in a phenomenon of intoxication and euphoria. In 1935, Albert Behnke discovered nitrogen as the cause of this clinical syndrome, a condition now known as nitrogen narcosis. Nitrogen narcosis consists of the development of euphoria, a false sense of security, and impaired judgment upon underwater descent using compressed air below 3-4 atmospheres (99 to 132 feet). At greater depths, symptoms can progress to loss of consciousness. The syndrome remains relatively unchanged in modern diving when compressed air is used. Behnke's use of non-nitrogen-containing gas mixtures subsequent to his discovery during the 1939 rescue of the wrecked submarine USS Squalus pioneered the use of non-nitrogen-containing gas mixtures, which are used by modern divers when working at great depth to avoid the effects of nitrogen narcosis.

  15. Characterizing sources of nitrate leaching from an irrigated dairy farm in Merced County, California

    NASA Astrophysics Data System (ADS)

    van der Schans, Martin L.; Harter, Thomas; Leijnse, Anton; Mathews, Marsha C.; Meyer, Roland D.

    2009-11-01

    Dairy farms comprise a complex landscape of groundwater pollution sources. The objective of our work is to develop a method to quantify nitrate leaching to shallow groundwater from different management units at dairy farms. Total nitrate loads are determined by the sequential calibration of a sub-regional scale and a farm-scale three-dimensional groundwater flow and transport model using observations at different spatial scales. These observations include local measurements of groundwater heads and nitrate concentrations in an extensive monitoring well network, providing data at a scale of a few meters and measurements of discharge rates and nitrate concentrations in a tile-drain network, providing data integrated across multiple farms. The various measurement scales are different from the spatial scales of the calibration parameters, which are the recharge and nitrogen leaching rates from individual management units. The calibration procedure offers a conceptual framework for using field measurements at different spatial scales to estimate recharge N concentrations at the management unit scale. It provides a map of spatially varying dairy farming impact on groundwater nitrogen. The method is applied to a dairy farm located in a relatively vulnerable hydrogeologic region in California. Potential sources within the dairy farm are divided into three categories, representing different manure management units: animal exercise yards and feeding areas (corrals), liquid manure holding ponds, and manure irrigated forage fields. Estimated average nitrogen leaching is 872 kg/ha/year, 807 kg/ha/year and 486 kg/ha/year for corrals, ponds and fields respectively. Results are applied to evaluate the accuracy of nitrogen mass balances often used by regulatory agencies to assess groundwater impacts. Calibrated leaching rates compare favorably to field and farm scale nitrogen mass balances. These data and interpretations provide a basis for developing improved management strategies.

  16. Severe leaching of trachytic glass without devitrification, Terceira, Azores

    SciTech Connect

    Mungall, J.E.; Martin, R.F. )

    1994-01-01

    Pumice produced during the subplinian phase of eruption of a peralkaline trachyte lava on the island of Terceira, Azores, has undergone extensive leaching at ambient conditions by groundwater, while remaining in a glassy state. Over 25% of F, Na, K, Si, Fe, Ti, and Mn originally present has been removed, whereas U, Al, Nb, Ca, Y, and Rb show smaller but significant losses. Thorium , Zr, Hf, Ta, and Lu have remained immobile. Water content (measured as LOI) has increased up to tenfold, whereas the Sr content has risen by up to 80%. The absence of devitrification requires that leached elements escaped by diffusing through the glass; a coefficient of chemical diffusion D[sub Na] between 1.8 X 10[sup [minus]19] cm[sup 2] s[sup [minus]1] and 6.1 X 10[sup [minus]19] cm[sup 2] s[sup [minus]1] has been calculated, in excellent agreement with previously published experimentally derived values for comparably low temperatures. Water has not replaced the leached cations on a charge-equivalent basis, a finding that requires an explanation other than simple binary interdiffusion. The authors suggest that a simultaneous influx of molecular water and cation exchange between Na[sup +] in the glass and H[sup +] in the groundwater opens the glass structure and frees cations, which can diffuse outward by hydrolysis of bridging oxygen atoms. Reported mobilities have important implications for such diverse fields as igneous petrology, nuclear waste management, and agriculture.

  17. Linking an economic model for European agriculture with a mechanistic model to estimate nitrogen and carbon losses from arable soils in Europe

    NASA Astrophysics Data System (ADS)

    Leip, A.; Marchi, G.; Koeble, R.; Kempen, M.; Britz, W.; Li, C.

    2008-01-01

    A comprehensive assessment of policy impact on greenhouse gas (GHG) emissions from agricultural soils requires careful consideration of both socio-economic aspects and the environmental heterogeneity of the landscape. We developed a modelling framework that links the large-scale economic model for agriculture CAPRI (Common Agricultural Policy Regional Impact assessment) with the biogeochemistry model DNDC (DeNitrification DeComposition) to simulate GHG fluxes, carbon stock changes and the nitrogen budget of agricultural soils in Europe. The framework allows the ex-ante simulation of agricultural or agri-environmental policy impacts on a wide range of environmental problems such as climate change (GHG emissions), air pollution and groundwater pollution. Those environmental impacts can be analyzed in the context of economic and social indicators as calculated by the economic model. The methodology consists of four steps: (i) definition of appropriate calculation units that can be considered as homogeneous in terms of economic behaviour and environmental response; (ii) downscaling of regional agricultural statistics and farm management information from a CAPRI simulation run into the spatial calculation units; (iii) designing environmental model scenarios and model runs; and finally (iv) aggregating results for interpretation. We show the first results of the nitrogen budget in croplands in fourteen countries of the European Union and discuss possibilities to improve the detailed assessment of nitrogen and carbon fluxes from European arable soils.

  18. Leaching Characteristics of Hanford Ferrocyanide Wastes

    SciTech Connect

    Edwards, Matthew K.; Fiskum, Sandra K.; Peterson, Reid A.; Shimskey, Rick W.

    2009-12-21

    A series of leach tests were performed on actual Hanford Site tank wastes in support of the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The samples were targeted composite slurries of high-level tank waste materials representing major complex, radioactive, tank waste mixtures at the Hanford Site. Using a filtration/leaching apparatus, sample solids were concentrated, caustic leached, and washed under conditions representative of those planned for the Pretreatment Facility in the WTP. Caustic leaching was performed to assess the mobilization of aluminum (as gibbsite, Al[OH]3, and boehmite AlO[OH]), phosphates [PO43-], chromium [Cr3+] and, to a lesser extent, oxalates [C2O42-]). Ferrocyanide waste released the solid phase 137Cs during caustic leaching; this was antithetical to the other Hanford waste types studied. Previous testing on ferrocyanide tank waste focused on the aging of the ferrocyanide salt complex and its thermal compatibilities with nitrites and nitrates. Few studies, however, examined cesium mobilization in the waste. Careful consideration should be given to the pretreatment of ferrocyanide wastes in light of this new observed behavior, given the fact that previous testing on simulants indicates a vastly different cesium mobility in this waste form. The discourse of this work will address the overall ferrocyanide leaching characteristics as well as the behavior of the 137Cs during leaching.

  19. δ15N constraints on long-term nitrogen balances in temperate forests.

    PubMed

    Perakis, Steven S; Sinkhorn, Emily R; Compton, Jana E

    2011-11-01

    Biogeochemical theory emphasizes nitrogen (N) limitation and the many factors that can restrict N accumulation in temperate forests, yet lacks a working model of conditions that can promote naturally high N accumulation. We used a dynamic simulation model of ecosystem N and δ(15)N to evaluate which combination of N input and loss pathways could produce a range of high ecosystem N contents characteristic of forests in the Oregon Coast Range. Total ecosystem N at nine study sites ranged from 8,788 to 22,667 kg ha(-1) and carbon (C) ranged from 188 to 460 Mg ha(-1), with highest values near the coast. Ecosystem δ(15)N displayed a curvilinear relationship with ecosystem N content, and largely reflected mineral soil, which accounted for 96-98% of total ecosystem N. Model simulations of ecosystem N balances parameterized with field rates of N leaching required long-term average N inputs that exceed atmospheric deposition and asymbiotic and epiphytic N(2)-fixation, and that were consistent with cycles of post-fire N(2)-fixation by early-successional red alder. Soil water δ(15)NO(3)(-) patterns suggested a shift in relative N losses from denitrification to nitrate leaching as N accumulated, and simulations identified nitrate leaching as the primary N loss pathway that constrains maximum N accumulation. Whereas current theory emphasizes constraints on biological N(2)-fixation and disturbance-mediated N losses as factors that limit N accumulation in temperate forests, our results suggest that wildfire can foster substantial long-term N accumulation in ecosystems that are colonized by symbiotic N(2)-fixing vegetation.

  20. Estimation of Nitrogen Pools in Irrigated Potato Production on Sandy Soil Using the Model SUBSTOR

    PubMed Central

    Prasad, Rishi; Hochmuth, George J.; Boote, Kenneth J.

    2015-01-01

    Recent increases in nitrate concentrations in the Suwannee River and associated springs in northern Florida have raised concerns over the contributions of non-point sources. The Middle Suwannee River Basin (MSRB) is of special concern because of prevalent karst topography, unconfined aquifers and sandy soils which increase vulnerability of the ground water contamination from agricultural operations- a billion dollar industry in this region. Potato (Solanum tuberosum L.) production poses a challenge in the area due to the shallow root system of potato plants, and low water and nutrient holding capacity of the sandy soils. A four-year monitoring study for potato production on sandy soil was conducted on a commercial farm located in the MSRB to identify major nitrogen (N) loss pathways and determine their contribution to the total environmental N load, using a partial N budget approach and the potato model SUBSTOR. Model simulated environmental N loading rates were found to lie within one standard deviation of the observed values and identified leaching loss of N as the major sink representing 25 to 38% (or 85 to 138 kg ha-1 N) of the total input N (310 to 349 kg ha-1 N). The crop residues left in the field after tuber harvest represented a significant amount of N (64 to 110 kg ha-1N) and posed potential for indirect leaching loss of N upon their mineralization and the absence of subsequent cover crops. Typically, two months of fallow period exits between harvest of tubers and planting of the fall row crop (silage corn). The fallow period is characterized by summer rains which pose a threat to N released from rapidly mineralizing potato vines. Strategies to reduce N loading into the groundwater from potato production must focus on development and adoption of best management practices aimed on reducing direct as well as indirect N leaching losses. PMID:25635904

  1. δ15N constraints on long-term nitrogen balances in temperate forests

    USGS Publications Warehouse

    Perakis, S.S.; Sinkhorn, E.R.; Compton, J.E.

    2011-01-01

    Biogeochemical theory emphasizes nitrogen (N) limitation and the many factors that can restrict N accumulation in temperate forests, yet lacks a working model of conditions that can promote naturally high N accumulation. We used a dynamic simulation model of ecosystem N and δ15N to evaluate which combination of N input and loss pathways could produce a range of high ecosystem N contents characteristic of forests in the Oregon Coast Range. Total ecosystem N at nine study sites ranged from 8,788 to 22,667 kg ha−1 and carbon (C) ranged from 188 to 460 Mg ha−1, with highest values near the coast. Ecosystem δ15N displayed a curvilinear relationship with ecosystem N content, and largely reflected mineral soil, which accounted for 96–98% of total ecosystem N. Model simulations of ecosystem N balances parameterized with field rates of N leaching required long-term average N inputs that exceed atmospheric deposition and asymbiotic and epiphytic N2-fixation, and that were consistent with cycles of post-fire N2-fixation by early-successional red alder. Soil water δ15NO3 − patterns suggested a shift in relative N losses from denitrification to nitrate leaching as N accumulated, and simulations identified nitrate leaching as the primary N loss pathway that constrains maximum N accumulation. Whereas current theory emphasizes constraints on biological N2-fixation and disturbance-mediated N losses as factors that limit N accumulation in temperate forests, our results suggest that wildfire can foster substantial long-term N accumulation in ecosystems that are colonized by symbiotic N2-fixing vegetation.

  2. Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions

    EPA Science Inventory

    Abstract for presentation on Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions. The abstract is attached.

  3. Effect of the leaching of calcium hydroxide from cement paste on mechanical and physical properties

    SciTech Connect

    Carde, C.; Francois, R.

    1997-04-01

    This paper deals with the effect of the leaching process of cement based materials on their mechanical and physical properties. In order to characterize this effect, the authors have performed experiments on cement paste samples. The leaching process was achieved by the use of a 50% concentrate solution of ammonium nitrate. Both compression tests and water porosity tests were conducted on micro-cylinder samples (10, 12, 14 and 20 mm of diameter) because of the slow kinetics of degradation due to the leaching. The deterioration of the cement paste and the mortar exposed to the action of the ammonium nitrate was manifested by a peripheral zone of less resistance. This process induces mainly a total leaching of Ca(OH){sub 2} and a progressive decalcification of C-S-H which leads to a gradient of C/S ratio in the leaching zone. Both mechanical tests and water porosity tests show that there is a linear variation of the loss of strength and the increase in porosity in relation to the ratio of degraded area over total area of the sample A{sub d}/A{sub t}. It means that both compressive resistance and water porosity of the leaching zone are constant whatever the size of the degraded zone and then whatever the time of exposure to the chemical attack. So the authors could venture the hypothesis that the dissolution of calcium hydroxide is the essential parameter governing both decrease in strength and increase in porosity.

  4. Contributions of acid deposition and natural processes to cation leaching from forest soils: a review

    SciTech Connect

    Johnson, D.W.; Van Miegroet, H.; Cole, D.W.; Richter, D.D.

    1983-01-01

    Methods of quantifying the roles of atmospheric acid inputs and internal acid generation by carbonic, organic, and nitric acids are illustrated by reviewing data sets from several intensively studied sites in North America. Some of the sites (tropical, Costa Rica (La Selva); temperate deciduous, Tennessee (Walker Branch); and temperate coniferous, Washington (Thompson)) received acid precipitation whereas others (northern, southeast Alaska (Petersburg); and subalpine, Washington Cascades (Findley Lake)) did not. Natural leaching by carbonic acid dominated soil leaching in the tropical and temperate coniferous sites, nitric acid (caused by nitrification) dominated leaching in an N-fixing temperate deciduous site (red alder in Washington), and organic acids dominated surface soil leaching in the subalpine site and contributed to leaching of surface soils in several other sites. Only at the temperate deciduous sites in eastern Tennessee did atmospheric acid input play a major role in soil leaching. In no case, however, are the annual net losses of cations regarded as alarming as compared to soil exchangeable cation capital.

  5. Nitrogen fertilization challenges the climate benefit of cellulosic biofuels

    NASA Astrophysics Data System (ADS)

    Ruan, Leilei; Bhardwaj, Ajay K.; Hamilton, Stephen K.; Robertson, G. Philip

    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 (N2O) 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 yields 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 CO2e ha-1 yr-1 in switchgrass fertilized at 56 kg N ha-1 to only -2.97 ± 0.18 Mg CO2e ha-1 yr-1 in switchgrass fertilized at 196 kg N ha-1. Minimizing N fertilizer use will be an important strategy for fully realizing the climate benefits of cellulosic biofuel production.

  6. 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 (N2O) 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 (R2 > 0.9, P < 0.001) and deviated further from the fixed percentage assumed for IPCC Tier 1 emission factors. Concomitantly, switchgrass yields became less responsivemore » 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 CO2e ha–1 yr–1 in switchgrass fertilized at 56 kgNha–1 to only –2.97 ± 0.18 MgCO2e 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

  7. Biochar and the nitrogen cycle: introduction.

    PubMed

    Clough, Tim J; Condron, Leo M

    2010-01-01

    Nitrogen (N) is an essential nutrient, and research to date shows that biochar potentially has the ability to manipulate the rates of N cycling in soil systems by influencing nitrification rates and adsorption of ammonia and increasing NH4+ storage by enhancing cation exchange capacity in soils. Its influence on these processes may have further implications in terms of reducing gaseous N losses such as N2O and nitrate leaching. However, further detailed research is required to fully understand the transformation mechanisms and fate of N when associated with biochar treated soils. The three research papers that comprise this special collection of papers on biochar and the nitrogen cycle focus on biochar's diverse ability to influence N cycling processes. These papers show for the first time (i) how microbial nitrification communities and function differ with exposure to biochar, (ii) how the length of time the soil has been in contact with biochar influences N transformation and how this can vary with soil type, and (iii) how composting of organic materials with biochar can reduce N losses and enhance the nutrient status of the composted product. Considerable knowledge gaps still exist in terms of understanding the precise mechanisms through which biochar influences soil N transformations, and how biochar affects both plant and microbial N supply. The general direction that research on biochar should focus on with respect to the N cycle is the effect(s) that biochar has on N transformation in soils, both chemical and biological mechanisms, and the fate of N applied to biochar treated soils. This research needs to be performed at both field plot and microbial scales.

  8. Leaching behaviour of wood treated with creosote.

    PubMed

    Becker, L; Matuschek, G; Lenoir, D; Kettrup, A

    2001-01-01

    The results of a laboratory investigation on the leaching behaviour of wood treated with creosote and of untreated wood are reported. A special leaching test derived from the German standard method DEV S4 test (DIN 38414) has been developed. Samples were leached in deionized water, in a solution buffered at pH 4.7 and in a solution of humic substances. The organic fraction of the leachate was extracted using liquid-liquid extraction. The extracts were analysed qualitatively with GC/MSD and quantified with GC/FID. The results were compared with those of Soxhlet-extracts from creosote-treated wood.

  9. ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

    DOEpatents

    Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

    1957-11-12

    A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

  10. Rapid transport and transformation of phosphorus species during the leaching of poultry manure amended soil

    NASA Astrophysics Data System (ADS)

    Giles, Courtney; Cade-Menun, Barbara; Liu, Corey; Hill, Jane

    2015-04-01

    The loss of phosphorus (P) from soils due to leaching is a major concern in heavily fertilized agricultural regions. The mobility and transformation of P species will depend on the source of manure fertilizer, leaching regime, and the extent of soil P saturation within the soil profile. We investigate spatial and temporal changes in the distribution of P species within a poultry manure-amended soil at two depths (0-5, 10-15 cm) as well as leachate P fractions during 10 weeks of leaching. Leachate P was primarily composed of dissolved fractions (soluble reactive P; dissolved unreactive P) and reached a maximum in the fourth week of leaching. In soils, the degree of P saturation (80%) and water extractable P (9 mg kg-1) were also greatest in week 4. 31P NMR spectra of the 0-5 cm depth indicate that surface soils were most similar to the poultry manure in week 4. During peak leaching, the proportion of orthophosphate (OrthoP) at the soil surface (0-5 cm; 80%) was greater than that from the lowest depth (10-15 cm; 72%), which contained relatively larger proportions of monoester-(17%) and diester-P classes (10%). Poultry manure likely contributed to the mobile pool of P species, including OrthoP, myo-inositol hexakisphosphate (myo-IHP), and nucleic acids. The appearance of neo- and D-chiro-IHP, as well as phospholipid signals during the leaching period indicate possible short-term (<10 week) contributions of organic P to the generation and leaching of OrthoP, under P-saturated conditions. Further work is needed to determine how fertilization and leaching will affect the mobility and transformation of P species across a wider range of soil types. Keywords: Phytate, organic phosphorus, degree of phosphorus saturation, soil, leachate, poultry manure

  11. Improved nitrogen management utilizing ground-penetrating-radar: A nine-year investigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water availability and efficient use of nitrogen are critical components of a sustainable and profitable agricultural system. Since nitrogen is typically excessively applied, considerable nitrogen may leach to and move through the subsurface. Our hypothesis is that knowledge of the subsurface hydr...

  12. Clinoptilolite Zeolite Influence on Inorganic Nitrogen in Silt Loam and Sandy Agricultural Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

  13. Clinoptilolite zeolite influence on inorganic nitrogen in silt loam and sandy agricultural soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

  14. Zeolite Soil Application Method Affects Inorganic Nitrogen, Moisture, and Corn Growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adoption of new management techniques which improve soil water storage and soil nitrogen plant availability yet limit nitrogen leaching may help improve environmental quality. A benchtop study was conducted to determine the influence of a single urea fertilizer rate (224 kilograms of Nitrogen per ...

  15. Clinoptilolite zeolite influence on nitrogen in a manure-amended sandy agricultural soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4-...

  16. A Mechanistic Treatment of the Dominant Soil Nitrogen Cycling Processes: Model Development, Testing, and Application

    SciTech Connect

    Riley, William; Maggi, F.; Gu, C.; Riley, W.J.; Hornberger, G.M.; Venterea, R.T.; Xu, T.; Spycher, N.; Steefel, C.; Miller, N.L.; Oldenburg, C.M.

    2008-05-01

    The development and initial application of a mechanistic model (TOUGHREACT-N) designed to characterize soil nitrogen (N) cycling and losses are described. The model couples advective and diffusive nutrient transport, multiple microbial biomass dynamics, and equilibrium and kinetic chemical reactions. TOUGHREACT-N was calibrated and tested against field measurements to assess pathways of N loss as either gas emission or solute leachate following fertilization and irrigation in a Central Valley, California, agricultural field as functions of fertilizer application rate and depth, and irrigation water volume. Our results, relative to the period before plants emerge, show that an increase in fertilizer rate produced a nonlinear response in terms of N losses. An increase of irrigation volume produced NO{sub 2}{sup -} and NO{sub 3}{sup -} leaching, whereas an increase in fertilization depth mainly increased leaching of all N solutes. In addition, nitrifying bacteria largely increased in mass with increasing fertilizer rate. Increases in water application caused nitrifiers and denitrifiers to decrease and increase their mass, respectively, while nitrifiers and denitrifiers reversed their spatial stratification when fertilizer was applied below 15 cm depth. Coupling aqueous advection and diffusion, and gaseous diffusion with biological processes, closely captured actual conditions and, in the system explored here, significantly clarified interpretation of field measurements.

  17. Leaky nitrogen cycle in pristine African montane rainforest soil

    NASA Astrophysics Data System (ADS)

    Rütting, Tobias; Cizungu Ntaboba, Landry; Roobroeck, Dries; Bauters, Marijn; Huygens, Dries; Boeckx, Pascal

    2015-10-01

    Many pristine humid tropical forests show simultaneously high nitrogen (N) richness and sustained loss of bioavailable N forms. To better understand this apparent upregulation of the N cycle in tropical forests, process-based understanding of soil N transformations, in geographically diverse locations, remains paramount. Field-based evidence is limited and entirely lacking for humid tropical forests on the African continent. This study aimed at filling both knowledge gaps by monitoring N losses and by conducting an in situ 15N labeling experiment in the Nyungwe tropical montane forest in Rwanda. Here we show that this tropical forest shows high nitrate (NO3-) leaching losses, confirming findings from other parts of the world. Gross N transformation rates point to an open soil N cycle with mineralized N nitrified rather than retained via immobilization; gross immobilization of NH4+ and NO3- combined accounted for 37% of gross mineralization, and plant N uptake is dominated by ammonium (NH4+). This study provided new process understanding of soil N cycling in humid tropical forests and added geographically independent evidence that humid tropical forests are characterized by soil N dynamics and N inputs sustaining bioavailable N loss.

  18. Hydrochemical Leaching of Wildfire Ash

    NASA Astrophysics Data System (ADS)

    Hamann, H.

    2008-12-01

    A century of fire suppression, combined with recent droughts has provoked some of the worst wildfire seasons in the western US. Although wild and prescribed fires are known to supply nutrients to grassland, shrubland and forest ecosystems, when ash and combustion byproducts are leached into surface waters the nutrients and other materials can affect aquatic ecosystems and pose a considerable risk to water quality. This ash may be persistent for periods as short as a storm or snowmelt event or up to several years, as suggested by periodic increases in dissolved nutrients and suspended solids. Here I present results from field sampling and bench scale experiments that examine the rate of change and chemical quality of leachate from ash samples collected from two wildfires that burned in Colorado in 2003 and 2006. Bench scale- experiments suggest that the conductivity of ash leachate increases in a continuous and modelable manner. Stream grab samples collected in burned and unburned areas within two weeks of the 2006 Mato Vega fire suggest an initial increase in pH, and conductivity, as well as an increase in solutes including dissolved organic carbon and manganese; however the results were spatially variable.

  19. [Effects of fertilization on the P accumulation and leaching in vegetable greenhouse soil].

    PubMed

    Zhao, Ya-jie; Zhao, Mu-qiu; Lu, Cai-yan; Shi, Yi; Chen, Xin

    2015-02-01

    A packed soil column experiment was conducted to investigate the effect of different fertilization practices on phosphorus (P) accumulation and leaching potential in a vegetable greenhouse soil with different fertility levels. The results showed that the leaching loss of total P in the leachates elevated with the increment of leaching time while the accumulative leaching loss of total P was relatively low, indicating P was mainly accumulated in the soil instead of in the leachate. At the end of the leaching experiment, soil fertility and fertilization treatment affected the content of total phosphorus and Olsen-P significantly. Compared with the low-level-fertility soil, the contents of total P and Olsen-P increased by 14.3% and 12.2% in the medium-level-fertility soil, 33.3% and 37.7% in the high-level-fertility soil. Total P in the combined application of poultry manure and chemical fertilizer (M+NPK) was elevated by 5.7% and 4.3%, compared with the NPK and M treatment. Compared with NPK treatment, Olsen-P in M and M + NPK treatments augmented by 13.0% and 3.1%, respectively. Soil total P and Olsen-P mainly accumulated in the 0-10 cm and 10-20 cm soil layers, and much less in the 20-40 cm soil layer.

  20. Leaching of chalcopyrite with sodium hypochlorite

    NASA Astrophysics Data System (ADS)

    Garlapalli, Ravinder Kumar

    Chalcopyrite is the most important copper mineral source and also a refractory mineral for leaching. Several processing routes have been proposed to overcome the environmental problems related to copper extraction from chalcopyrite. In this study, the leaching of chalcopyrite has been investigated with a new reagent sodium hypochlorite (NaOCl). Experiments were carried out in two stages: conversion of chalcopyrite to cupric oxide with NaOCl solution in the first stage, followed by dissolution of the cupric oxide to cupric ion with 1 normal sulfuric acid at room temperature in the second stage. In the first stage leaching, the initial pH varied from 12.5 to 13.7; the temperature, from 35 to 75°C; NaOCl concentration, from 0.2 to 0.85 molar; and the chalcopyrite dosage, from 1 to 10 grams/500 ml. The leaching conversion showed a maximum (68.3%) around pH 13.2 at 0.5 molar of hypochlorite concentration and 65°C in 1 hour. The reagent consumption ratio, defined as the number of moles of hypochlorite consumed to leach one mole of chalcopyrite is found to be much higher than its stoichiometric ratio of 8.5. It reached 57.6 when the solid dosage was 1 gram/500 ml and decreased to 12.9 when the solid dosage was increased to 10 grams/500 ml. It was found that the leaching rate of chalcopyrite in the first stage was controlled by chemical reaction with the activation energy of 50.2 kJ/mol (12.0 kcal/mol). A leaching scheme was identified in which 98% chalcopyrite was leached by adding hypochlorite stock solution stepwise in less than three hours.

  1. LEACHING BOUNDARY MOVEMENT IN SOLIDIFIED/STABILIZED WASTE FORMS

    EPA Science Inventory

    Investigation of the leaching of cement-based waste forms in acetic acid solutions found that acids attacked the waste form from the surface toward the center. A sharp leaching boundary was identified in every leached sample, using pH color indica- tors. The movement of the leach...

  2. Verifiable metamodels for nitrate losses to drains and groundwater in the Corn Belt, USA

    USGS Publications Warehouse

    Nolan, B.T.; Malone, R.W.; Gronberg, J.A.; Thorp, K.R.; Ma, L.

    2012-01-01

    Nitrate leaching in the unsaturated zone poses a risk to groundwater, whereas nitrate in tile drainage is conveyed directly to streams. We developed metamodels (MMs) consisting of artificial neural networks to simplify and upscale mechanistic fate and transport models for prediction of nitrate losses by drains and leaching in the Corn Belt, USA. The two final MMs predicted nitrate concentration and flux, respectively, in the shallow subsurface. Because each MM considered both tile drainage and leaching, they represent an integrated approach to vulnerability assessment. The MMs used readily available data comprising farm fertilizer nitrogen (N), weather data, and soil properties as inputs; therefore, they were well suited for regional extrapolation. The MMs effectively related the outputs of the underlying mechanistic model (Root Zone Water Quality Model) to the inputs (R 2 = 0.986 for the nitrate concentration MM). Predicted nitrate concentration was compared with measured nitrate in 38 samples of recently recharged groundwater, yielding a Pearson's r of 0.466 (p = 0.003). Predicted nitrate generally was higher than that measured in groundwater, possibly as a result of the time-lag for modern recharge to reach well screens, denitrification in groundwater, or interception of recharge by tile drains. In a qualitative comparison, predicted nitrate concentration also compared favorably with results from a previous regression model that predicted total N in streams. ?? This article not subject to U.S. Copyright. Published 2011 by the American Chemical Society.

  3. Verifiable metamodels for nitrate losses to drains and groundwater in the Corn Belt, USA.

    PubMed

    Nolan, Bernard T; Malone, Robert W; Gronberg, Jo Ann; Thorp, Kelly R; Ma, Liwang

    2012-01-17

    Nitrate leaching in the unsaturated zone poses a risk to groundwater, whereas nitrate in tile drainage is conveyed directly to streams. We developed metamodels (MMs) consisting of artificial neural networks to simplify and upscale mechanistic fate and transport models for prediction of nitrate losses by drains and leaching in the Corn Belt, USA. The two final MMs predicted nitrate concentration and flux, respectively, in the shallow subsurface. Because each MM considered both tile drainage and leaching, they represent an integrated approach to vulnerability assessment. The MMs used readily available data comprising farm fertilizer nitrogen (N), weather data, and soil properties as inputs; therefore, they were well suited for regional extrapolation. The MMs effectively related the outputs of the underlying mechanistic model (Root Zone Water Quality Model) to the inputs (R(2) = 0.986 for the nitrate concentration MM). Predicted nitrate concentration was compared with measured nitrate in 38 samples of recently recharged groundwater, yielding a Pearson's r of 0.466 (p = 0.003). Predicted nitrate generally was higher than that measured in groundwater, possibly as a result of the time-lag for modern recharge to reach well screens, denitrification in groundwater, or interception of recharge by tile drains. In a qualitative comparison, predicted nitrate concentration also compared favorably with results from a previous regression model that predicted total N in streams.

  4. Assessing pesticide leaching under climate change: The role of climate input uncertainty

    NASA Astrophysics Data System (ADS)

    Steffens, Karin; Larsbo, Mats; Moeys, Julien; Jarvis, Nicholas J.; Kjellström, Erik; Lewan, Elisabet

    2013-04-01

    amounts and temperatures in periods that are critical for pesticide losses from drained clay soils in Sweden (spring and autumn) and to the choice of the pesticide application date. The choice of a specific climate model projection could not only change the magnitude of the predicted future losses but also the direction of change independent from pesticide properties and application season and thus, strongly influence our estimations of future changes in pesticide leaching risks and thereby linked threats to surface water quality. Although the parameter uncertainty was relatively large, 50 to 80% of the different parameter sets predicted a similar change in pesticide leaching losses from present to future, which underlined the impact of climate input uncertainty on the results.

  5. Dolomite phosphate rock (DPR) application in acidic sandy soil in reducing leaching of phosphorus and heavy metals-a column leaching study.

    PubMed

    Yang, Yuangen; He, Zhenli; Yang, Xiaoe; Stoffella, Peter J

    2013-06-01

    A column leaching study was designed to investigate the leaching potential of phosphorus (P) and heavy metals from acidic sandy soils applied with dolomite phosphate rock (DPR) fertilizers containing varying amounts of DPR material and N-Viro soils. DPR fertilizers were made from DPR materials mixing with N-Viro soils at the ratios of 30, 40, 50, 60, and 70 %, and applied in acidic sandy soils at the level of 100 mg available P per kilogram soil. A control and a soluble P chemical fertilizer were also included. The amended soils were incubated at room temperature with 70 % field water holding capacity for 21 days before packed into a soil column and subjected to leaching. Seven leaching events were conducted at days 1, 3, 7, 14, 28, 56, and 70, respectively, and 258.9 mL of deionized water was applied at each leaching events. The leachate was collected for the analyses of pH, electrical conductivity (EC), dissolved organic carbon (DOC), major elements, and heavy metals. DPR fertilizer application resulted in elevations up to 1 unit in pH, 7-10 times in EC, and 20-40 times in K and Ca concentrations, but 3-10 times reduction in P concentration in the leachate as compared with the chemical fertilizer or the control. After seven leaching events, DPR fertilizers with adequate DPR materials significantly reduced cumulative leaching losses of Fe, P, Mn, Cu, and Zn by 20, 55, 3.7, 2.7, and 2.5 times than chemical fertilizer or control. Even though higher cumulative losses of Pb, Co, and Ni were observed after DPR fertilizer application, the loss of Pb, Co, and Ni in leachate was <0.10 mg (in total 1,812 mL leachate). Significant correlations of pH (negative) and DOC (positive) with Cu, Pb, and Zn (P<0.01) in leachate were observed. The results indicated that DPR fertilizers had a great advantage over the soluble chemical fertilizer in reducing P loss from the acidic sandy soil with minimal likelihood of heavy metal risk to the water environment. pH elevation and high

  6. Zinc Leaching from Tire Crumb Rubber

    NASA Astrophysics Data System (ADS)

    Rhodes, E. P.; Ren, J.; Mays, D. C.

    2010-12-01

    Recent estimates indicate that more than 2 billion scrap tires are currently stockpiled in the United States and approximately 280 million more tires are added annually. Various engineering applications utilize recycled tires in the form of shredded tire crumb rubber. However, the use of tire crumb rubber may have negative environmental impacts, especially when the rubber comes into contact with water. A review of the literature indicates that leaching of zinc from tire crumb rubber is the most significant water quality concern associated with using this material. Zinc is generally used in tire manufacturing, representing approximately 1.3% of the final product by mass. This study will report results from the U.S. Environmental Protection Agency’s (EPA’s) Synthetic Precipitation Leaching Procedure, batch leaching tests, and column leaching tests performed to quantify the process by which zinc leaches from tire crumb rubber into water. Results are interpreted with a first-order kinetic attachment/detachment model, implemented with the U.S. Agricultural Research Service software HYDRUS-1D, in order to determine the circumstances when zinc leaching from tire crumb rubber would be expected to comply with the applicable discharge limits. One potential application for recycled tires is replacing sand with tire crumb rubber in granular media filters used for stormwater pollution control. For this to be a viable application, the total zinc in the stormwater discharge must be below the EPA’s benchmark value of 0.117 mg/L.

  7. Optimization of the factors that accelerate leaching

    SciTech Connect

    Fuhrmann, M.; Pietrzak, R.F.; Franz, E.M.; Heiser, J.H. III; Colombo, P.

    1989-03-01

    The prediction of long-term leachability of low-level radioactive waste forms is an essential element of disposal-site performance assessment. This report describes experiments and modeling techniques used to develop an accelerated leach test that meets this need. The acceleration in leaching rates caused by the combinations of two or more factors were experimentally determined. These factors were identified earlier as being able to individually accelerate leaching. They are: elevated temperature, the size of the waste form, the ratio of the volume of leachant to the surface area of the waste form, and the frequency of replacement of the leachant. The solidification agents employed were ones that are currently used to treat low-level radioactive wastes, namely portland type I cement, bitumen, and vinyl ester-styrene. The simulated wastes, sodium sulfate, sodium tetraborate, and incinerator ash, are simplified representatives of typical low-level waste streams. Experiments determined the leaching behavior of the radionuclides of cesium (Cs-137), strontium (Sr-85), and cobalt (Co-60 or Co-57) from several different formulations of solidification agents and waste types. Leaching results were based upon radiochemical and elemental analyses of aliquots of the leachate, and on its total alkalinity and pH at various times during the experiment (up to 120 days). Solid phase analyses were carried out by Scanning/Electron Microscopy and Energy Dispersive Spectroscopy on the waste forms before and after some leaching experiments. 43 refs., 96 figs., 16 tabs.

  8. NEXT GENERATION LEACHING TESTS FOR EVALUATING ...

    EPA Pesticide Factsheets

    In the U.S. as in other countries, there is increased interest in using industrial by-products as alternative or secondary materials, helping to conserve virgin or raw materials. The LEAF and associated test methods are being used to develop the source term for leaching or any inorganic constituents of potential concern (COPC) in determining what is environmentally acceptable. The leaching test methods include batch equilibrium, percolation column and semi-dynamic mass transport tests for monolithic and compacted granular materials. By testing over a range of values for pH, liquid/solid ratio, and physical form of the material, this approach allows one data set to be used to evaluate a range of management scenarios for a material, representing different environmental conditions (e.g., disposal or beneficial use). The results from these tests may be interpreted individually or integrated to identify a solid material’s characteristic leaching behavior. Furthermore the LEAF approach provides the ability to make meaningful comparisons of leaching between similar and dissimilar materials from national and worldwide origins. To present EPA's research under SHC to implement validated leaching tests referred to as the Leaching Environmental Assessment Framework (LEAF). The primary focus will be on the guidance for implementation of LEAF describing three case studies for developing source terms for evaluating inorganic constituents.

  9. Phytoremediation of a nitrogen-contaminated desert soil by native shrubs and microbial processes

    DOE PAGES

    Glenn, Edward P.; Jordan, Fiona; Waugh, W. Joseph

    2016-02-24

    Here, we combined phytoremediation and soil microbial nitrification and denitrification cycles to reduce nitrate and ammonium levels at a former uranium mill site near Monument Valley, Arizona. Ammonia used in uranium extraction was present throughout the soil profile. Sulfate,applied as sulfuric acid to solubilize uranium, was also present in the soil. These contaminants were leaching from a denuded area where a tailings pile had been removed and were migrating away from the site in groundwater. We planted the source area with two deep-rooted native shrubs, Atriplex cansescens and Sarcobatus vermiculatus, and irrigated transplants for 11 years at 20% the ratemore » of potential evapotranspiration to stimulate growth, then discontinued irrigation for 4 years. Over 15 years, total nitrogen levels dropped 82%, from 347 to 64 mg kg–1. Analysis of δ15N supported our hypothesis that coupled microbial nitrification and denitrification processes were responsible for the loss of N. Soil sulfate levels changed little; however, evapotranspiration reduced sulfate leaching into the aquifer. For arid sites where traditional pump-and-treat methods are problematic, the Monument Valley data suggest that alternatives that incorporate native plants and rely on vadose zone biogeochemistry and hydrology could be a sustainable remediation for nitrogen contaminated soil.« less

  10. Phytoremediation of a nitrogen-contaminated desert soil by native shrubs and microbial processes

    SciTech Connect

    Glenn, Edward P.; Jordan, Fiona; Waugh, W. Joseph

    2016-02-24

    Here, we combined phytoremediation and soil microbial nitrification and denitrification cycles to reduce nitrate and ammonium levels at a former uranium mill site near Monument Valley, Arizona. Ammonia used in uranium extraction was present throughout the soil profile. Sulfate,applied as sulfuric acid to solubilize uranium, was also present in the soil. These contaminants were leaching from a denuded area where a tailings pile had been removed and were migrating away from the site in groundwater. We planted the source area with two deep-rooted native shrubs, Atriplex cansescens and Sarcobatus vermiculatus, and irrigated transplants for 11 years at 20% the rate of potential evapotranspiration to stimulate growth, then discontinued irrigation for 4 years. Over 15 years, total nitrogen levels dropped 82%, from 347 to 64 mg kg–1. Analysis of δ15N supported our hypothesis that coupled microbial nitrification and denitrification processes were responsible for the loss of N. Soil sulfate levels changed little; however, evapotranspiration reduced sulfate leaching into the aquifer. For arid sites where traditional pump-and-treat methods are problematic, the Monument Valley data suggest that alternatives that incorporate native plants and rely on vadose zone biogeochemistry and hydrology could be a sustainable remediation for nitrogen contaminated soil.

  11. Nitrogen release from rock and soil under simulated field conditions

    USGS Publications Warehouse

    Holloway, J.M.; Dahlgren, R.A.; Casey, W.H.

    2001-01-01

    A laboratory study was performed to simulate field weathering and nitrogen release from bedrock in a setting where geologic nitrogen has been suspected to be a large local source of nitrate. Two rock types containing nitrogen, slate (1370 mg N kg-1) and greenstone (480 mg N kg-1), were used along with saprolite and BC horizon sand from soils derived from these rock types. The fresh rock and weathered material were used in batch reactors that were leached every 30 days over 6 months to simulate a single wet season. Nitrogen was released from rock and soil materials at rates between 10-20 and 10-19 mo1 N cm-2 s-1. Results from the laboratory dissolution experiments were compared to in situ soil solutions and available mineral nitrogen pools from the BC horizon of both soils. Concentrations of mineral nitrogen (NO3- + NH4+) in soil solutions reached the highest levels at the beginning of the rainy season and progressively decreased with increased leaching. This seasonal pattern was repeated for the available mineral nitrogen pool that was extracted using a KCl solution. Estimates based on these laboratory release rates bracket stream water NO3-N fluxes and changes in the available mineral nitrogen pool over the active leaching period. These results confirm that geologic nitrogen, when present, may be a large and reactive pool that may contribute as a non-point source of nitrate contamination to surface and ground waters. ?? 2001 Elsevier Science B.V. All rights reserved.

  12. Carbon loss and chemical changes from permafrost collapse in the northern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Mu, Cuicui; Zhang, Tingjun; Zhang, Xiankai; Li, Lili; Guo, Hong; Zhao, Qian; Cao, Lin; Wu, Qingbai; Cheng, Guodong

    2016-07-01

    Permafrost collapse, known as thermokarst, can alter soil properties and carbon emissions. However, little is known regarding the effects of permafrost collapse in upland landscapes on the biogeochemical processes that affect carbon balance. In this study, we measured soil carbon and physiochemical properties at a large thermokarst feature on a hillslope in the northeastern Tibetan Plateau. We categorized surfaces into three different microrelief patches based on type and extent of collapse (control, drape, and exposed areas). Permafrost collapse resulted in substantial decreases of surface soil carbon and nitrogen stocks, with losses of 29.6 ± 4.2% and 28.9 ± 3.1% for carbon and nitrogen, respectively, in the 0-10 cm soil layer. Laboratory incubation experiments indicated that control soil had significantly higher CO2 production rates than that of drapes. The results from Fourier transform infrared spectroscopy analysis showed that exposed soils accumulated some organic matter due to their low position within the feature, which was accompanied by substantial changes in the chemical structure and characteristics of the soil carbon. Exposed soils had higher hydrocarbon and lignin/phenol backbone content than in control and drape soils in the 0-10 cm layer. This study demonstrates that permafrost collapse can cause abundant carbon and nitrogen loss, potentially from mineralization, leaching, photodegradation, and lateral displacement. These results demonstrate that permafrost collapse redistributes the soil organic matter, changes its chemical characteristics, and leads to losses of organic carbon due to the greenhouse gas emission.

  13. Methane/nitrogen separation process

    DOEpatents

    Baker, Richard W.; Lokhandwala, Kaaeid A.; Pinnau, Ingo; Segelke, Scott

    1997-01-01

    A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.

  14. Methane/nitrogen separation process

    DOEpatents

    Baker, R.W.; Lokhandwala, K.A.; Pinnau, I.; Segelke, S.

    1997-09-23

    A membrane separation process is described for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. The authors have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen. 11 figs.

  15. From Gene Expression to the Earth System: Isotopic Constraints on Nitrogen Cycling Across Scales

    NASA Astrophysics Data System (ADS)

    Houlton, B. Z.

    2015-12-01

    A central motivation of the Biogeosciences is to understand the cycling of biologically essential elements over multiple scales of space and time. This charge is vital to basic knowledge of Earth system functioning. It is also relevant to many of the global challenges we face, such as climate change, biodiversity conservation, and the multifaceted role of global fertilizer use in maximizing human health and well-being. Nitrogen is connected to all of these; yet it has been one of the more vexing elements to quantitatively appraise across systems and scales. Here I discuss how research in my group has been exploring the use of natural nitrogen isotope abundance (15N/14N) as a biogeochemical tracer - from the level of gene expression to nitrogen's role in global climate change. First, I present evidence for a positive correlation between the bacterial genes that encode for gaseous nitrogen production (i.e., nirS) and the 15N/14N of soil extractable nitrate pools across an array of terrestrial ecosystems. Second, I demonstrate how these local-scale results fit with our work on ecosystem-scale nitrogen isotope budgets, where we quantify a uniformly small isotope effect (i.e., < 1 per mil) of nitrogen leaching losses from tropical rainforest to highly disturbed arid sites. Third, I present results from our global isotope model, which is based on results from our field investigations, providing a new nitrogen "benchmarking" scheme for global computational models and climate change forecasts. Finally, I move to a new research frontier where we have been developing a technique to measure the nitrogen isotope composition of ancient terrestrial plant compounds (i.e., chlorins) buried in the soil. This research aims to address the response of the nitrogen cycle to glacial-interglacial transitions over millennia, which is beyond the window of experimental testing. Together, this research highlights the utility of nitrogen isotope composition in addressing the myriad scales of

  16. Nitrate leaching concentrations in the Netherlands decreased more than expected

    NASA Astrophysics Data System (ADS)

    Boumans, Leo; Fraters, Dico; Wattel, Esther

    2014-05-01

    The implementation of EU environmental directives and national policies into measures has led to a decrease in nitrogen (N) surplus in agriculture, notably at dairy farms in the 1995-2002 period. In addition, N emissions to air from agricultural fields have been reduced, and atmospheric N deposition on nature areas subsequently lessened. The nitrate concentrations in root zone leaching at dairy farms and nature areas in the Sand region of the Netherlands also decreased. These decreases were larger than would be expected based on the decreases in net loads. We have formulated and tested hypotheses to explain these extra decreases at farms and in nature areas. Dairy farms cover about 60% of the area in the sandy region of the Netherlands. They have shown a nitrate leaching decrease of 100 mg/l during the 1992-2010 period (67%). The N-surplus at dairy farms decreased from about 340 to 180 kg/ha in this period (47%). Other farm management factors may have caused the additional decrease in root zone leaching concentration on farm level. The main potential factors are the ratio grassland - arable land, the grazing intensity and the ratio artificial fertilizer N - manure N. There are no indications that the ratio grassland - arable land or the ratio artificial fertilizer N - manure N significantly changed between 1992 and 2010. The mowing percentage, as an indicator for grazing intensity, increased from about 180 to 290% in the study period. About 80% (80 mg/l) of the decrease at dairy farms can be attributed to a lower N-surplus and about 20% (20 mg/l) is postulated to be caused by an increasing mowing percentage or less fodder grazing. Nature areas cover about 20% of the area in the Sand region. Nitrate concentrations in root zone leaching in nature areas showed a decrease of 55% in 2010 compared to 1990. Yet in rainwater, the concentration decrease is only 40%. Several factors may cause an additional decrease in nitrate concentration particularly an increase of plant

  17. Leaching of Chalcopyrite with Sodium Hypochlorite

    NASA Astrophysics Data System (ADS)

    Garlapalli, Ravinder K.; Cho, Eung Ha; Yang, Ray Y. K.

    2010-04-01

    A laboratory study was conducted on the leaching of chalcopyrite with NaOCl (sodium hypochlorite). Experiments were carried out in the following two stages: (1) Chalcopyrite was converted to CuO (cupric oxide) with a sodium hypochlorite solution, and (2) cupric oxide was dissolved to cupric ions with 1 normal sulfuric acid at room temperature. In the first-stage leaching, the initial pH varied from 12.5 to 13.7, the temperature from 35 °C to 75 °C, the sodium hypochlorite concentration from 0.2 to 0.85 molar, and the chalcopyrite dosage from 1 to 10 g/500 ml. The leaching conversion showed a maximum (68.3 pct) around a pH of 13.2 at 0.5 molar OCl- (hypochlorite) concentration and at 65 °C in 1 hour. The reagent consumption ratio—defined as the number of moles of hypochlorite consumed to leach 1 mole of chalcopyrite—was much higher than its stoichiometric ratio of 8.5. It reached 57.6 when the solid dosage was 1 g/500 ml and decreased to 12.9 when the solid dosage was increased to 10 g/500 ml. The leaching rate of chalcopyrite in the first stage was controlled by a chemical reaction with the activation energy of 50.2 kJ/mol (12.0 kcal/mol). A leaching scheme was identified in which 98 pct of the chalcopyrite was leached by adding hypochlorite stock solution stepwise in less than 3 hours.

  18. Leaching of lead from zinc leach residue in acidic calcium chloride aqueous solution

    NASA Astrophysics Data System (ADS)

    Wang, Le; Mu, Wen-ning; Shen, Hong-tao; Liu, Shao-ming; Zhai, Yu-chun

    2015-05-01

    A process with potentially reduced environmental impacts and occupational hazards of lead-bearing zinc plant residue was studied to achieve a higher recovery of lead via a cost-effective and environmentally friendly process. This paper describes an optimization study on the leaching of lead from zinc leach residue using acidic calcium chloride aqueous solution. Six main process conditions, i.e., the solution pH value, stirring rate, concentration of CaCl2 aqueous solution, liquid-to-solid (L/S) ratio, leaching temperature, and leaching time, were investigated. The microstructure and components of the residue and tailing were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). On the basis of experimental results, the optimum reaction conditions were determined to be a solution pH value of 1, a stirring rate of 500 r·min-1, a CaCl2 aqueous solution concentration of 400 g·L-1, a liquid-to-solid mass ratio of 7:1, a leaching temperature of 80°C, and a leaching time of 45 min. The leaching rate of lead under these conditions reached 93.79%, with an iron dissolution rate of 19.28%. Silica did not take part in the chemical reaction during the leaching process and was accumulated in the residue.

  19. Long-term lessons on pesticide leaching obtained via the Danish Pesticide Leaching Assessment Programme

    NASA Astrophysics Data System (ADS)

    Rosenbom, A. E.; Olsen, P.; Plauborg, F.; Grant, R.; Juhler, R. K.; Brüsch, W.; Kjær, J.

    2014-12-01

    To avoid any unacceptable influence on the environment posed by pesticides and their degradation products, all pesticides used in the European Union needs authorization. The authorization procedure includes assessing the leaching risk of both pesticides and their degradation products to the groundwater. There are shortcomings to the procedure, however, as revealed by the results of the Danish Pesticide Leaching Assessment Programme from the period 1990/2000 to 2012 (app. twelve years). This monitoring program has for this period assessed leaching into groundwater via the variably-saturated zone of 43 pesticides applied in accordance with current regulations on sandy and loamy agricultural fields, and 47 of their degradation products. Three types of leaching scenario were not fully captured by the authorization procedure: i) long-term leaching of degradation products of pesticides applied on potato crops cultivated in sandy soils, ii) leaching of strongly sorbing pesticides after autumn application on loamy soils, and iii) leaching of various pesticides and their degradation products following early summer application on loamy soils. The monitoring data revealed that the authorization procedure was unable to predict leaching scenarios for a number of pesticides in hydrogeological settings dominated by rapid preferential transport via e.g. biopores that bypasses the retardation (sorption and degradation) of the plow layer. Such settings are primarily present in the autumn, but can also occur during the early summer in connection with the formation of a structural seal on the soil surface.

  20. Impact of peatland restoration on nutrient and carbon leaching from contrasting sites in southern Finland

    NASA Astrophysics Data System (ADS)

    Vasander, Harri; Sallantaus, Tapani; Koskinen, Markku

    2010-05-01

    Impacts of peatland restoration on nutrient and carbon leaching from contrasting sites in southern Finland Tapani Sallantaus1, Markku Koskinen2, Harri Vasander2 1)Finnish Environment Institute, Biodiversity unit, Box 140, FIN-00251 Helsinki, Finland, tapani.sallantaus@ymparisto.fi 2)Department of Forest Sciences, University of Helsinki, Box 27, FIN-00014 University of Helsinki, Finland, markku.koskinen@helsinki.fi, harri.vasander@helsinki.fi Less than 20 % of the original mire area of southern Finland is still in natural state. Even many peatlands in today's nature conservation areas had been partly or totally drained before conservation. Until now, about 15000 ha of peatlands have been restored in conservation areas. Here we present data concerning changes in leaching due to restoration in two contrasting areas in southern Finland. The peatlands in Seitseminen have originally been fairly open, growing stunted pine, and unfertile, either bogs or poor fens. The responses of tree stand to drainage in the 1960s were moderate, and the tree stand before restoration was about 50 m3/ha, on average. The trees were partly harvested before filling in the ditches mainly in the years 1997-1999 . The peatlands of Nuuksio are much more fertile than those in Seitseminen, and had greatly responded to drainage, which took place already in the 1930s and 1950s. The tree stand consisted mainly of spruce and exceeded 300 m3/ha in large part of the area. The ditches were dammed in the autumn 2001 and the tree stand was left standing. Runoff water quality was monitored in three basins in both areas. To obtain the leaching rates, we used simulated runoff data obtained from the Finnish Environment Institute, Hydrological Services Division. The responses in leaching were in the same direction in both cases. However, especially when calculated per restored hectare (Table 1), the responses were much stronger in the more fertile areas of Nuuksio for organic carbon and nitrogen, but not so much

  1. Assessment risk of phosphorus leaching from calcareous soils using soil test phosphorus.

    PubMed

    Jalali, Mohsen; Jalali, Mahdi

    2017-03-01

    Accurate estimation of phosphorus (P) leaching is important because excess P may reduce surface and ground water quality. Little attention has been paid to estimate P leaching from soil tests in calcareous soils. The relation between different soil tests P (STP), P sorption index (PSI) and degree of P saturation (DPS) and leaching of P were examined for assessing the risk of P loss from calcareous soils. Columns leaching repacked with native soils were leached with either distilled water or 10 mM CaCl2 solutions, separately. Four leaching events were performed at four days, and 28.7 mm of distilled water or 10 mM CaCl2 solutions was applied at each leaching events. Compared with distilled water, CaCl2 had a small ability to solubilize P from soils. Concentration of P in leachate in both leaching solutions was exceeding 0.1 mg l(-1) associated with eutrophication. Cumulative P leached P was ranged from 0.17 to 18.59 mg P kg(-1) and 0.21-8.16 mg P kg(-1), when distilled water and 10 mM CaCl2 solutions were applied, respectively and it was higher in sandy clay loam soils compared with clay soils. Among evaluated environmental soil P tests, PCaCl2-3h (P extracted by 10 mM CaCl2 for 3 h), PCaCl2-1h (P extracted by 10 mM CaCl2 for 1 h) were more accurate than other soil P tests for predicting P concentration in the leachates in both leaching solutions and accounting for 83% and 72% of variation of P concentration, respectively. The water extractable P (WEP) (r = 0.771) and Olsen-P (POls)(r = 0.739) were significantly related to the leached P concentration using distilled water solution in a split line model, with a change point of 27.4 mg P kg(-1) and 61.5 mg P kg(-1), respectively. Various DPS were calculated and related to the leached P concentration. Based on P extracted by Mehlich-3 (PM3) and HCl (PHCl) and PSI, the change point of the relationship between leached P concentration and DPSM3-3 (PM3(PM3+PSI)×100) and DPSHCl-2 (PHCl(PHCl+PSI)×100

  2. Evaluating a Coupled Carbon and Nitrogen Cycle Model at a Pacific Northwest Douglas-fir Forest in Canada

    NASA Astrophysics Data System (ADS)

    Arain, M.; Yuan, F.; Shaikh, M.; Black, T.

    2004-05-01

    Nitrogen availability could be a key factor to enhance or limit plant photosynthesis under global climate change. This study presents a coupled nitrogen and carbon cycle model incorporated in the Canadian Land Surface Scheme (CLASS) which is used in the Canadian General Circulation Model. The nitrogen cycle model, which follows Dickinson et al., 2002 is coupled to a previously derived carbon model in CLASS. Nitrogen cycling processes taken into account include biological fixation, soil mineralization, immobilization, nitrification, denitrification, volatilization, leaching, root uptake and allocation to various plant components. Root nitrogen uptake depends on soil mineral nitrogen content, ion physical transport, root interface, and also on plant-growth demand for this nutrient. Leaf Rubisco-nitrogen concentration was modeled to determine variations in maximum rate of Rubisco activity,Vcmax. The coupled carbon and nitrogen model was tested at a Douglas-fir forest, growing on Vancouver Island, British Columbia, Canada, using observed eddy covariance flux data from 1998 to 2000. Simulated carbon and nitrogen uptake/loss rates were in broad agreement with observation. The simulated annual soil mineralized nitrogen was 6.3, 5.3, and 6.0 g m-2 in 1998, 1999 and 2000, respectively. The annual nitrogen uptake was 1.78, 1.65, and 1.76 g m-2, respectively. The simulated leaf nitrogen ranged from 1.81 to 1.87 g m-2 leaf area in the growing season, while observed leaf nitrogen values were 1.7 g m-2 in the lower canopy, and 2.56 g m-2 in the upper canopy. Observed Rubisco nitrogen was about 17% of total leaf nitrogen as compared to 16% simulated value. The modeled Vcmax in top leaves (Vcmax0) was as low as 15 imol C m-2 s-1 during the non-growing season, and as high as 80 imol C m-2 s-1 during the full growing season. Comparison of half-hourly observed and simulated gross ecosystem productivity (GEP), ecosystem respiration (R) and net ecosystem productivity (NEP) from 1998

  3. The mineralogical phase transformation of invisible gold-concentrate by microwave heating, and enhancement of their gold leaching rate

    NASA Astrophysics Data System (ADS)

    Bak, Geonyoung; Kim, Bongju; Choi, Nagchoul; Park*, Cheonyoung

    2015-04-01

    In this study, in order to obtain the maximum Au leaching rate, an invisible gold concentrate sample was microwave-treated and a thiourea leaching experiment was performed. It is found that gold exists as invisible as a result of observation with an optical microscope and an electron microscope. As the invisible gold concentrate sample was exposed to microwave longer, its temperature and weight loss were increased together and its S content was decreased. The conditions for the maximum Au leaching rate and the fast leaching effect were a particle size of -325×400 mesh, exposure to microwave for 70 minutes, 1.0 g of thiourea, 0.0504 g of sodium sulfite and 0.425 g of ferric sulfate. However, the condition under which Au was leached out to the maximum was applied to the control sample, but its Au leaching rate was just in a range of 78% to 88%. Such results suggest that the effect of sodium sulfite and ferric sulfate was more effective in the microwave-treated sample than in the control sample. Therefore, it was confirmed that the complete and very fast Au leaching can be achieved by means of the microwave pretreatment of invisible gold concentrate.

  4. Investigation of Copper Ammonia Leaching from Smelter Slags: Characterization, Leaching and Kinetics

    NASA Astrophysics Data System (ADS)

    Bidari, Ehsan; Aghazadeh, Valeh

    2015-10-01

    Although ammonia leaching of copper from slags has been reported generally as a part of copper slag utilization methods, but no detailed studies have been reported in the literature. In this research, we tried to investigate the effect of different parameters on ammonia leaching of copper from copper smelting slag by identifying different copper-bearing phases and following them during leaching time. Mineralogical characterization of the smelting slag (1.7 pct Cu) was done using X-ray fluorescence, X-ray diffraction, optical microscopy, diagnostic leaching tests, and scanning electron microscopy. The characterization studies indicated that main copper-bearing species are soluble copper oxides and chalcocite along with minor amount of covellite, bornite, blister copper particles, and chalcopyrite. It was also found that only approximately 0.2 pct Cu was present in the insoluble bulk silicate phases. These results suggest that approximately 88 pct of the total copper of slag could be extracted by ammonia sulfide leaching. Leaching tests were carried out and the effects of various parameters, namely pH, ammonia concentration, temperature, presence of oxygen, stirring speed, and pulp density were examined on copper leaching. The temperature and stirring speed had the most pronounced effect on the copper leaching, whereas ammonia affected the leaching yield at low concentrations of ammonia. It was found that 78 pct of Cu could be extracted within 4 hours and under optimum conditions: T = 343 K (70 °C), 2M ammonia, pH 10.5, stirring speed = 900 rpm, pulp density = 10 pct ( w s/ v). The kinetic data were analyzed with the shrinking core models, and it was found that the leaching process is controlled by both the interfacial transfer and diffusion across the product layer and the activation energy is calculated to be 49.4 kJ mol-1.

  5. Effect on Nitrogen Balance, Thermogenesis, Body Composition, Satiety, and Circulating Branched Chain Amino Acid Levels up to One Year after Surgery: Protocol of a Randomized Controlled Trial on Dietary Protein During Surgical Weight Loss

    PubMed Central

    Pi-Sunyer, Xavier; Vidal, Josep; Miner, Patricia; Boirie, Yves; Laferrère, Blandine

    2016-01-01

    Background Bariatric surgery (BS), the most effective treatment for severe obesity, typically results in 40-50 kg weight loss in the year following the surgery. Beyond its action on protein metabolism, dietary protein intake (PI) affects satiety, thermogenesis, energy efficiency, and body composition (BC). However, the required amount of PI after surgical weight loss is not known. The current daily PI recommendation for diet-induced weight loss is 0.8 g/kg ideal body weight (IBW) per day, but whether this amount is sufficient to preserve fat-free mass during active surgical weight loss is unknown. Objective To evaluate the effect of a 3-month dietary protein supplementation (PS) on nitrogen balance (NB), BC, energy expenditure, and satiety in women undergoing either gastric bypass or vertical sleeve gastrectomy. Methods In this randomized prospective study, participants will be randomized to a high protein supplementation group (1.2 g/kg IBW per day) or standard protein supplementation group (0.8 g/kg IBW per day) based on current guidelines. Outcome measures including NB, BC, circulating branched chain amino acids, and satiety, which will be assessed presurgery, and at 3-months and 12-months postsurgery. Results To date, no studies have examined the effect of dietary PS after BS. Current guidelines for PI after surgery are based on weak evidence. Conclusions The results of this study will contribute to the development of evidence-based data regarding the safe and optimal dietary PI and supplementation after BS. Trial Registration Clinicaltrials.gov NCT02269410; http://clinicaltrials.gov/ct2/show/NCT02269410 (Archived by WebCite at http://www.webcitation.org/6m2f2QLeg). PMID:27895003

  6. [Nitrogen and water cycling of typical cropland in the North China Plain].

    PubMed

    Pei, Hong-wei; Shen, Yan-jun; Liu, Chang-ming

    2015-01-01

    Intensive fertilization and irrigation associated increasing grain production has led to serious groundwater depletion and soil/water pollution in the North China Plain (NCP). Intensive agriculture changes the initial mass and energy balance, and also results in huge risks to the water/soil resources and food security regionally. Based on the research reports on the nitrogen cycle and water cycle in typical cropland (winter wheat and summer corn) in the NCP during the past 20 years, and the meteorological data, field experiments and surveys, we calculated the nitrogen cycle and water-cycle for this typical cropland. Annual total nitrogen input were 632 kg N . hm-2, including 523 kg N . hm-2 from commercial fertilizer, 74 kg N . hm-2 from manure, 23 kg N . hm-2 from atmosphere, and 12 kg N . hm-2 from irrigation. All of annual outputs summed to 532 kg N . hm-2 including 289 kg N . hm-2 for crop, 77 kg N . hm-2 staying in soil profile, leaching 104 kg N . hm-2, 52 kg N . hm-2 for ammonia volatilization, 10 kg N . hm-2 loss in nitrification and denitrification. Uncertainties of the individual cases and the summary process lead to the unbalance of nitrogen. For the dominant parts of the field water cycle, annual precipitation was 557 mm, irrigation was 340 mm, while 762 mm was for evapotranspiration and 135 mm was for deep percolation. Considering uncertainties in the nitrogen and water cycles, coupled experiments based on multi-disciplines would be useful for understanding mechanisms for nitrogen and water transfer processes in the soil-plant-atmosphere-continuum (SPAC) , and the interaction between nitrogen and water, as well as determining the critical threshold values for sustainability of soil and water resources in the NCP.

  7. Orchard nitrogen management: Which nitrogen source is best?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Suboptimal management of nitrogen fertility in pecan orchards leads to a loss of nutmeat yield and quality, but also a waste of natural resources and money. This article reviews several basic guiding principles useful to orchard managers when developing nitrogen management strategies, and determini...

  8. Effect of nitrogen content and additional straw on changes in chemical composition, volatile losses, and ammonia emissions from dairy manure during long-term storage.

    PubMed

    Aguerre, M J; Wattiaux, M A; Hunt, T; Lobos, N E

    2012-06-01

    Twelve 200-L barrels were used to determine the effects of N content and straw addition on changes in chemical composition and volatile losses measured by mass balance of dairy manure during a 136-d storage period. In addition, on d 0, 3, 6, 12, 28, 56, and 136, rate of NH₃-N emission was measured, and core samples were collected to characterize fermentation pattern. High N (3.06% N, HN) and low N (2.75% N, LN) manures were obtained from cows fed diets with 17.2 and 15.2% crude protein (dry matter basis), respectively. On d 0, manure scraped from a freestall barn floor was diluted with water to 10% dry matter and loaded in barrels with (+S) or without (-S) mixing 22g of chopped wheat straw per kilogram of undiluted manure. Data were analyzed as a randomized complete block with a 2×2 factorial arrangement of treatments and 3 replications. We observed no interaction between treatments for the reported measurements, but several day-of-storage by treatment interactions were found. Throughout storage, total NH₃-N (TAN, NH₃-N + NH₄⁺-N; 71.9 vs. 104.3 mg/dL), pH (6.40 vs. 6.74), and total volatile fatty acids (TVFA, starting on d 12) were lower for LN relative to HN manure. In the presence of straw, crust formation occurred between d 12 and 28, and pH became lower and TVFA became higher starting on d 56, compared with no straw. Treatments did not influence loss of organic matter, organic N, organic C, or N, which averaged 31, 29, 26, and 20%, respectively. However, neutral detergent fiber loss was 44% higher for +S relative to -S manure. Consistent reductions in the C:N ratio indicated proportionally higher volatile C loss than volatile N loss during storage. Overall rate of NH₃-N emission was 36% lower for LN than for HN manure. In the presence of straw, rate of NH₃-N emission did not differ until after crust formation, but was 67% lower on d 56 and 95% lower on d 136, when it was barely detectable, compared with manure with no straw. Manure pH was highly

  9. Nitrogen release during coal combustion

    SciTech Connect

    Baxter, L.L.; Mitchell, R.E.; Fletcher, T.H.; Hurt, R.H.

    1995-02-01

    Experiments in entrained flow reactors at combustion temperatures are performed to resolve the rank dependence of nitrogen release on an elemental basis for a suite of 15 U.S. coals ranging from lignite to low-volatile bituminous. Data were obtained as a function of particle conversion, with overall mass loss up to 99% on a dry, ash-free basis. Nitrogen release rates are presented relative to both carbon loss and overall mass loss. During devolatilization, fractional nitrogen release from low-rank coals is much slower than fractional mass release and noticeably slower than fractional carbon release. As coal rank increases, fractional nitrogen release rate relative to that of carbon and mass increases, with fractional nitrogen release rates exceeding fractional mass and fractional carbon release rates during devolatilization for high-rank (low-volatile bituminous) coals. At the onset of combustion, nitrogen release rates increase significantly. For all coals investigated, cumulative fractional nitrogen loss rates relative to those of mass and carbon passes through a maximum during the earliest stages of oxidation. The mechanism for generating this maximum is postulated to involve nascent thermal rupture of nitrogen-containing compounds and possible preferential oxidation of nitrogen sites. During later stages of oxidation, the cumulative fractional loss of nitrogen approaches that of carbon for all coals. Changes in the relative release rates of nitrogen compared to those of both overall mass and carbon during all stages of combustion are attributed to a combination of the chemical structure of coals, temperature histories during combustion, and char chemistry.

  10. Anthropogenic nitrogen sources and exports in a village-scale catchment in Southeast China.

    PubMed

    Cao, Wenzhi; Hong, Huasheng; Zhang, Yuzhen; Chen, Nengwang; Zeng, Yue; Wang, Weiping

    2006-01-01

    An experimental village-scale catchment was selected for investigation of nitrogen (N) sources and exports. The mean N application rate over the catchment was 350.2 kg N ha(-1), but this rate varied spatially and temporally. The N leaching loss rate varied from 8.1 to 52.7 kg N ha(-1) under different land use regimes. The average N leaching loss rate was 13.4 kg N ha(-1) over the whole catchment, representing about 3.8% of the total N inputs. The N export rate through stormflows was 28.8 kg N ha(-1), about 8.2% of the total N inputs. Seasonal patterns showed that 95% of N exports through stormflows occurred during July to September in 2002. Overall, the maximum riverine N exports were 12.1% of total N inputs and 15.5% of the inorganic fertilizer N applied. Understanding N sources and exports in a village-scale catchment can provide a knowledge base for amelioration of diffuse agricultural pollution.

  11. Sensitivity of N-retention and export to temperature and nitrogen deposition forcing for a humid Pacific North West conifer site

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Tague, C.; Garcia, E.; Choate, J.

    2012-12-01

    Global climate change and anthropogenic activities both affect nitrogen cycling and its interaction with carbon and water in the ecosystem. Changes in the balance of carbon, nitrogen and water, particularly in forested environments, may be an important feedback to global climate system and affect ecosystem and human health. The goal of this study is to use a GIS-based regional hydro-ecological simulation system (RHESSys) to model interactions between climate and nitrogen cycling at a local/plot scale within the Pacific Northwest of the United States. This is also a pilot study/precursor to a regional modeling effort, BioEarth, which examines the interaction among carbon, nitrogen and water at a regional scale in the context of global climate change. We compare estimates for a relatively dry and a wet forested conifer focus sites in the Pacific Northwest. We seek to improve our understanding of the sensitivity of forest nitrogen cycling to increases in nitrogen deposition and temperature and to develop scaling relationships for integrating coupled climate-N cycling processes into regional scale models. At our focus sites, we use sensitivity analysis to derive the directionality, linearity, and thresholds in nitrogen-cycling responses to the changes in nitrogen deposition and temperature. We compare RHESSys estimates of annual nitrogen leaching, nitrification, denitrification, vegetation nitrogen uptake, and changes in soil and vegetation nitrogen pools under scenarios of increasing nitrogen deposition and temperature, over a 30 year record of inter-annual climate variability. Our results indicate that for the relatively wet site: 1. There is a substantial capacity for the HJA ecosystem to absorb increasing N-deposition inputs. Similarly, the adequate water supply at this site leads to increasing vegetation productivity with warming. 2. For both temperature and nitrogen deposition increase scenarios, responses are relatively linear and the thresholds, where the

  12. Saltstone Oxidation Study: Leaching Method

    SciTech Connect

    Langton, C. A.; Stefanko, D. B.; Burns, H. H.

    2013-02-24

    Cementitious waste forms can be designed to chemically stabilize selected contaminants, such as Tc{sup +7} and Cr{sup +6}, by chemically reduction to lower valance states, Tc{sup +4} and Cr{sup +3}, respectively, and precipitation of these species in alkaline media as low solubility solid phases. Data for oxidation of this type of cementitious waste form cured under field conditions as a function of time is required for predicting the performance of the waste form and disposal facility. The rate of oxidation (oxidation front advancement) is an important parameter for predicting performance because the solubilities of some radionuclide contaminants, e.g., technetium, are a function of the oxidation state. A non-radioactive experiment was designed for quantifying the oxidation front advancement using chromium, as an approximate redox-sensitive surrogate (Cr{sup +6} / Cr{sup +3}) for technetium (Tc{sup +7} / Tc{sup +4}). Nonradioactive cementitious waste forms were prepared in the laboratory and cured under both laboratory and ?field conditions.? Laboratory conditions were ambient temperature and sealed sample containers. Field conditions were approximated by curing samples in open containers which were placed inside a plastic container stored outdoors at SRS. The container had a lid and was instrumented with temperature and humidity probes. Subsamples as thin as 0.2 mm were taken as a function of distance from the exposed surface of the as-cast sample. The subsamples were leached and the leachates were analyzed for chromium, nitrate, nitrite and sodium. Nitrate, nitrite, and sodium concentrations were used to provide baseline data because these species are not chemically retained in the waste form matrix to any significant extent and are not redox sensitive. ?Effective? oxidation fronts for Cr were measured for samples containing 1000, 500 and 20 mg/kg Cr added as soluble sodium chromate, Na{sub 2}CrO{sub 4}. For a sample cured for 129 days under field conditions

  13. Effect of dietary adipic acid and corn dried distillers grains with solubles on laying hen performance and nitrogen loss from stored excreta with or without sodium bisulfate.

    PubMed

    Romero, C; Abdallh, M E; Powers, W; Angel, R; Applegate, T J

    2012-05-01

    Effects of dietary adipic acid (0 vs. 1%) and corn dried distillers grains with solubles (DDGS; 0 vs. 20%) were evaluated on hen performance and egg characteristics from 26 to 34 wk of age. Four isocaloric and isonitrogenous diets were randomly assigned to blocks of 6 consecutive cages (36 cages per diet; 2 hens per cage). On wk 2 and 7 of the experiment, excreta were collected by cage block, mixed, and equally split into 2 containers. Sodium bisulfate (SBS) was spread (8.8 kg/100 m(2)) on the top surface of half of the containers. All containers were stored uncovered for 14 d at room temperature. Excreta pH, DM, and N content were measured on d 0, 7, and 14 of storage. Feed intake (112 g/d per hen), egg production (96.1%), and egg specific gravity (1.079 g/g) were not affected by diet. On excreta collection day, a synergy (P = 0.014) between dietary adipic acid and DDGS was detected, as the lowest excreta pH was obtained with the diet including both adipic acid and DDGS. On d 7 of storage, excreta pH was still reduced by dietary adipic acid (P = 0.046) and DDGS (P < 0.001), but a week later, only dietary DDGS decreased excreta pH (8.91 vs. 9.21; P < 0.001). Whereas dietary adipic acid had no influence on excreta N loss, excreta from hens fed 20% DDGS lost 19.7% more N (P = 0.039) during storage than hens not eating DDGS. Surface amendment of excreta with SBS increased excreta DM content, with the effect being even more marked on d 14 of storage (increase of 6.7 percentage units; P < 0.001), consistently decreased excreta pH during storage (P < 0.001) and reduced N loss by 26.1% for the 14 d of storage period.

  14. Assessing the Fate of Nitrogen Deposition on the Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Roybal, C.; Belnap, J.; Floyd-Hanna, L.; Crews, T.; Reed, S.

    2014-12-01

    Anthropogenic nitrogen (N) deposition is a growing concern in the western U.S., and is known to modify ecosystem composition and function. Arches National Park is near an identified 'hotspot' of N pollution in the Southwest U.S. There is real concern regarding how the area's drylands will respond to elevated deposition. Yet, our understanding of potential responses remains poor. Uncertainties persist regarding how these systems will hold and cycle additional N, and how N inputs will affect other aspects of biogeochemistry. We used a field fertilization experiment in Arches NP to explore three questions: 1) does added N stay within soil and for how long; 2) are N additions primarily utilized by native grass and the soil microbial community; and 3) is N leaving the system as gas (NOx, N2O) or in leached forms? Results indicate added N remained in the plots even 90 days after fertilization: soil NO3- concentrations were consistently elevated and were related to the amount of fertilization. Significant amounts of N left the system through leaching and as gas (N2O and NOx); in particular, NOx losses were greater in the plots receiving 8 kg N/ha/yr relative to the control plots, a pattern that matched soil NO3- concentrations. While treatment effects were significant, soil moisture was the strongest control over gas efflux rates, and we observed significant interactions between fertilization treatment and soil moisture at the time of sample collection. These data support the idea that N strongly interacts with rainfall patterns to regulate pulse-driven losses of excess N. There was no treatment effect in foliar N concentrations, but treatment effects on soil P concentrations and microbial biomass stoichiometry suggest that N addition has a broad influence on other biogeochemical dynamics. Data suggest that this arid, low N ecosystem passes a threshold of ecological change at low levels of N, although much of the additional N is relatively quickly lost from the system.

  15. Indicators: Nitrogen

    EPA Pesticide Factsheets

    Nitrogen, like phosphorus, is a critical nutrient required for all life. Nitrogen can occur in rivers and streams, lakes, and coastal waters in several forms including ammonia (NH3), nitrates (NO3), and nitrites (NO2).

  16. Nutrient Leaching during Establishment of Simulated Residential Landscapes.

    PubMed

    Loper, Shawna J; Shober, Amy L; Wiese, Christine; Denny, Geoffrey C; Stanley, Craig D

    2013-01-01

    Research evaluating nutrient losses during the establishment of plant material in mixed residential landscapes is limited. The objectives of this study were to determine the effect of vegetative cover type, compost application, and tillage on nutrient losses during the establishment of landscape plants. Twenty-four small plots constructed with subsoil fill were planted with St. Augustinegrass [ (Walter) Kuntze] and mixed ornamental species in a randomized complete block design. Plots received composted dairy manure solids at a rate of 0 or 50.8 m ha- in combination with shallow tillage or aeration. Cumulative leachate loads and flow-weighted mean concentrations of NH-N, NO + NO-N, and dissolved reactive P (DRP) were calculated periodically and annually to assess nutrient leaching from landscape plots. Higher cumulative leachate volume, inorganic N and DRP loads, and mean NO + NO-N and DRP concentrations were observed under ornamental cover during one or more study periods, which we attribute to differences in root density and shoot biomass between mixed ornamental species and turfgrass during establishment. Greater cumulative leachate inorganic N loads were reported from composted soils than from unamended soils or soils receiving only tillage or aeration. Inorganic N and DRP loads were similar in magnitude to reported leaching losses from agricultural systems. Better management of nutrients and water in woody ornamental plant beds during plant establishment is needed due to differences in plant growth habits compared with turfgrass. Nutrient content of organic amendments should be considered when applying these materials as a soil conditioner in new residential landscapes.

  17. Long-term leaching from MSWI air-pollution-control residues: leaching characterization and modeling.

    PubMed

    Hyks, Jiri; Astrup, Thomas; Christensen, Thomas H

    2009-02-15

    Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sn, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) air-pollution-control residues was monitored during 24 months of column percolation experiments; liquid-to-solid (L/S) ratios of 200-250L/kg corresponding to more than 10,000 years in a conventional landfill were reached. Less than 2% of the initially present As, Cu, Pb, Zn, Cr, and Sb had leached during the course of the experiments. Concentrations of Cd, Fe, Mg, Hg, Mn, Ni, Co, Sn, Ti, and P were generally bellow 1microg/L; overall less than 1% of their mass leached. Column leaching data were further used in a two-step geochemical modeling in PHREEQC in order to (i) identify solubility controlling minerals and (ii) evaluate their interactions in a water-percolated column system over L/S of 250L/kg. Adequate predictions of pH, alkalinity, and the leaching of Ca, S, Al, Si, Ba, and Zn were obtained in a simultaneous calculation. Also, it was suggested that removal of Ca and S together with depletion of several minerals apparently caused dissolution of ettringite-like phases. In turn, significant increase in leaching of oxyanions (especially Sb and Cr) was observed at late stage of leaching experiments.

  18. Leaching Behavior of Heavy Metals from Cement Pastes Using a Modified Toxicity Characteristic Leaching Procedure (TCLP).

    PubMed

    Huang, Minrui; Feng, Huajun; Shen, Dongsheng; Li, Na; Chen, Yingqiang; Shentu, Jiali

    2016-03-01

    As the standard toxicity characteristic leaching procedure (TCLP) can not exhaust the acid neutralizing capacity of the cement rotary kiln co-processing solid wastes products which is particularly important for the assessment of the leaching concentrations of heavy metals. A modified TCLP was proposed. The extent of leaching of heavy metals is low using the TCLP and the leaching performance of the different metals can not be differentiated. Using the modified TCLP, however, Zn leaching was negligible during the first 180 h and then sharply increased (2.86 ± 0.18 to 3.54 ± 0.26 mg/L) as the acidity increased (pH < 6.0). Thus, Zn leaching is enhanced using the modified TCLP. While Pb leached readily during the first 126 h and then leachate concentrations decreased to below the analytical detection limit. To conclude, this modified TCLP is a more suitable method for these cement rotary kiln co-processing products.

  19. EPA's ''Lead leaching from submersible well pumps''

    SciTech Connect

    Not Available

    1994-06-01

    An attempt is made to provide comprehensive answers to questions EPA anticipates those involved in the environmental health profession may encounter from public concern in response to national media coverage of drinking water submersible well pumps and lead leaching. In laboratory tests, several models of new, previously unused submersible pumps with brass and bronze components have been found to leach high levels of lead into the water that comes in contact with these pumps. The findings of these tests indicate cause for concern to users of such pumps and a need for further research. Questions concerning the extent of the problem, health effects, and solutions are addressed.

  20. Nitrogen in aquatic ecosystems.

    PubMed

    Rabalais, Nancy N

    2002-03-01

    Aquatic ecosystems respond variably to nutrient enrichment and altered nutrient ratios, along a continuum from fresh water through estuarine, coastal, and marine systems. Although phosphorus is considered the limiting nutrient for phytoplankton production in freshwater systems, the effects of atmospheric nitrogen and its contribution to acidification of fresh waters can be detrimental. Within the estuarine to coastal continuum, multiple nutrient limitations occur among nitrogen, phosphorus, and silicon along the salinity gradient and by season, but nitrogen is generally considered the primary limiting nutrient for phytoplankton biomass accumulation. There are well-established, but nonlinear, positive relationships among nitrogen and phosphorus flux, phytoplankton primary production, and fisheries yield. There are thresholds, however, where the load of nutrients to estuarine, coastal and marine systems exceeds the capacity for assimilation of nutrient-enhanced production, and water-quality degradation occurs. Impacts can include noxious and toxic algal blooms, increased turbidity with a subsequent loss of submerged aquatic vegetation, oxygen deficiency, disruption of ecosystem functioning, loss of habitat, loss of biodiversity, shifts in food webs, and loss of harvestable fisheries.

  1. Fertilizer source effects on phosphate and nitrate leaching through simulated golf greens.

    PubMed

    Shuman, L M

    2003-01-01

    Phosphorus and nitrogen leached from high-porosity golf greens can adversely affect surface water and groundwater quality. Greenhouse and field lysimeter experiments were carried out to determine the effects of eight fertilizer sources on P and N leaching from simulated golf greens. Phosphorus appeared in the leachate later than nitrate-N, and the highest concentrations were for the soluble 20-20-20 and the 16-25-12 starter fertilizers. The other six sources resulted in lower P concentrations. The soluble 20-20-20 and the 16-25-12 sources each resulted in 43% of the added P eluting in the leachate, whereas the others varied from 15 to 25%. For nitrate-N the lowest cumulative mass was for the controlled-release 13-13-13 and sulfur-coated urea. A higher percentage of applied P than applied N leached from both field and greenhouse lysimeters. However, the amounts of P leached for the field lysimeters were lower than for the greenhouse columns.

  2. Losses of Ammonia and Nitrate from Agriculture and Their Effect on Nitrogen Recovery in the European Union and the United States between 1900 and 2050.

    PubMed

    van Grinsven, Hans J M; Bouwman, Lex; Cassman, Kenneth G; van Es, Harold M; McCrackin, Michelle L; Beusen, Arthur H W

    2015-03-01

    Historical trends and levels of nitrogen (N) budgets and emissions to air and water in the European Union and the United States are markedly different. Agro-environmental policy approaches also differ, with emphasis on voluntary or incentive-based schemes in the United States versus a more regulatory approach in the European Union. This paper explores the implications of these differences for attaining long-term policy targets for air and water quality. Nutrient surplus problems were more severe in the European Union than in the United States during the 1970s and 1980s. The EU Nitrates and National Emission Ceilings directives contributed to decreases in fertilizer use, N surplus, and ammonia (NH) emissions, whereas in the United States they stabilized, although NH emissions are still increasing. These differences were analyzed using statistical data for 1900-2005 and the global IMAGE model. IMAGE could reproduce NH emissions and soil N surpluses at different scales (European Union and United States, country and state) and N loads in the Rhine and Mississippi. The regulation-driven changes during the past 25 yr in the European Union have reduced public concerns and have brought agricultural N loads to the aquatic environment closer to US levels. Despite differences in agro-environmental policies and agricultural structure (more N-fixing soybean and more spatially separated feed and livestock production in the United States than in the European Union), current N use efficiency in US and EU crop production is similar. IMAGE projections for the IAASTD-baseline scenario indicate that N loading to the environment in 2050 will be similar to current levels. In the United States, environmental N loads will remain substantially smaller than in the European Union, whereas agricultural production in 2050 in the United States will increase by 30% relative to 2005, as compared with an increase of 8% in the European Union. However, in the United States, even rigorous mitigation

  3. Development of nitrogen and methane losses in the first eight weeks of lactation in Holstein cows subjected to deficiency of utilisable crude protein under restrictive feeding conditions.

    PubMed

    Sutter, Franz; Schwarm, Angela; Kreuzer, Michael

    2017-02-01

    Low-protein diets are increasingly being used in dairy cow nutrition to minimise noxious nitrogen (N) emissions. However, at parturition, the lower milk yield at that time may mask deficiency in dietary utilisable crude protein (uCP; equivalent to metabolisable protein). Under restrictive feeding conditions, farmers would limit the feed allowance to match the lower measured milk yield, thereby exacerbating the deficiency. The consequences for N emission intensity per kg milk yield and methane emissions are unknown. In this study, two diets were fed to nine Holstein cows each from parturition onwards. One diet was complete and the other was calculated as 20% deficient in uCP. Feed allowance was always oriented towards the measured milk yield. In each of the first eight lactation weeks, intake and excretion were measured for 5 d. On the last 2 d of this period, methane emission was measured in respiration chambers. The statistical model included treatment, week and interaction as effects. The real levels of uCP and energy supply across the 8 weeks were 33% and 15% below requirements, respectively, in the Deficient cows. In addition, the Deficient cows consumed 18% less dry matter (caused by substantial refusals in week 1, where energy supply was according to requirements) and produced 25% less milk (26 vs. 34 kg/d). Cows in both groups used dietary N with similar efficiency for milk protein synthesis and excreted similar proportions of the N ingested via urine and faeces. This resulted in both treatments having similar N emission intensities per kg milk N and similar urinary N as a proportion of total excreta N, suggesting a similar potential for gaseous N emissions from the manure per kg of milk. The Deficient cows emitted 22% less methane overall but had similar methane yield and emission intensity to the Controls. In conclusion, a reduction in crude protein intake immediately after parturition does not reduce N emission per unit of milk when associated with u

  4. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    SciTech Connect

    Allegrini, E.; Butera, S.; Kosson, D.S.; Van Zomeren, A.; Van der Sloot, H.A.; Astrup, T.F.

    2015-04-15

    Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results

  5. The contribution of leaching to the rapid release of nutrients and carbon in the early decay of wetland vegetation

    USGS Publications Warehouse

    Davis, S. E.; Childers, D.L.; Noe, G.B.

    2006-01-01

    Our goal was to quantify the coupled process of litter turnover and leaching as a source of nutrients and fixed carbon in oligotrophic, nutrient-limited wetlands. We conducted poisoned and non-poisoned incubations of leaf material from four different perennial wetland plants (Eleocharis spp., Cladium jamaicense, Rhizophora mangle and Spartina alterniflora) collected from different oligotrophic freshwater and estuarine wetland settings. Total phosphorus (TP) release from the P-limited Everglades plant species (Eleocharis spp., C. jamaicense and R. mangle) was much lower than TP release by the salt marsh plant S. alterniflora from N-limited North Inlet (SC). For most species and sampling times, total organic carbon (TOC) and TP leaching losses were much greater in poisoned than non-poisoned treatments, likely as a result of epiphytic microbial activity. Therefore, a substantial portion of the C and P leached from these wetland plant species was bio-available to microbial communities. Even the microbes associated with S. alterniflora from N-limited North Inlet showed indications of P-limitation early in the leaching process, as P was removed from the water column. Leaves of R. mangle released much more TOC per gram of litter than the other species, likely contributing to the greater waterborne [DOC] observed by others in the mangrove ecotone of Everglades National Park. Between the two freshwater Everglades plants, C. jamaicense leached nearly twice as much P than Eleocharis spp. In scaling this to the landscape level, our observed leaching losses combined with higher litter production of C. jamaicense compared to Eleocharis spp. resulted in a substantially greater P leaching from plant litter to the water column and epiphytic microbes. In conclusion, leaching of fresh plant litter can be an important autochthonous source of nutrients in freshwater and estuarine wetland ecosystems. ?? Springer 2006.

  6. Phosphorus leaching in manure-amended Atlantic Coastal Plain soils.

    PubMed

    Butler, Jennifer S; Coale, Frank J

    2005-01-01

    Targeting the sources of phosphorus (P) and transport pathways of drainage from agricultural land will assist in the reduction of P loading to surface waters. Our research investigated the vertical movement of P from dairy manure and broiler litter through four Atlantic Coastal Plain soils. A randomized split-plot design with two main-plot tillage treatments (no tillage [NT] and chisel tillage [CH]) and five manure P rate split-plot treatments was used at each location. The split-plot P rates were 0, 100, 200, 300, and 400 kg P ha(-1) yr(-1). Four consecutive years of manure application began at all sites 5 yr before sampling. Soils were sampled to a depth of 150 cm from each split plot in seven depth increments and analyzed for soil test phosphorus (STP), water-extractable soil phosphorus (WSP), and degree of phosphorus saturation (DPS). The DPS of the 0- to 15-cm depths confirmed that at the 100 kg P ha(-1) yr(-1) application rate, all sites exceeded the threshold for P saturation (30%). At depths greater than 30 cm, DPS was typically below the 30% saturation threshold. The DPS change points ranged from 25 to 34% for the 0- to 90-cm depths. Our research concluded that the risk of P leaching through the matrix of the Atlantic Coastal Plain soils studied was not high; however, P leaching via macropore bypass may contribute to P loss from these soils.

  7. ALUMINUM AND CHROMIUM LEACHING WORKSHOP WHITEPAPER

    SciTech Connect

    McCabe, D; Jeff Pike, J; Bill Wilmarth, B

    2007-04-25

    A workshop was held on January 23-24, 2007 to discuss the status of processes to leach constituents from High Level Waste (HLW) sludges at the Hanford and Savannah River Sites. The objective of the workshop was to examine the needs and requirements for the HLW flowsheet for each site, discuss the status of knowledge of the leaching processes, communicate the research plans, and identify opportunities for synergy to address knowledge gaps. The purpose of leaching of non-radioactive constituents from the sludge waste is to reduce the burden of material that must be vitrified in the HLW melter systems, resulting in reduced HLW glass waste volume, reduced disposal costs, shorter process schedules, and higher facility throughput rates. The leaching process is estimated to reduce the operating life cycle of SRS by seven years and decrease the number of HLW canisters to be disposed in the Repository by 1000 [Gillam et al., 2006]. Comparably at Hanford, the aluminum and chromium leaching processes are estimated to reduce the operating life cycle of the Waste Treatment Plant by 20 years and decrease the number of canisters to the Repository by 15,000-30,000 [Gilbert, 2007]. These leaching processes will save the Department of Energy (DOE) billions of dollars in clean up and disposal costs. The primary constituents targeted for removal by leaching are aluminum and chromium. It is desirable to have some aluminum in glass to improve its durability; however, too much aluminum can increase the sludge viscosity, glass viscosity, and reduce overall process throughput. Chromium leaching is necessary to prevent formation of crystalline compounds in the glass, but is only needed at Hanford because of differences in the sludge waste chemistry at the two sites. Improving glass formulations to increase tolerance of aluminum and chromium is another approach to decrease HLW glass volume. It is likely that an optimum condition can be found by both performing leaching and improving

  8. Use of open-path FTIR and inverse dispersion technique to quantify gaseous nitrogen loss from an intensive vegetable production site

    NASA Astrophysics Data System (ADS)

    Bai, Mei; Suter, Helen; Lam, Shu Kee; Sun, Jianlei; Chen, Deli

    2014-09-01

    An open-path Fourier transform infrared (OP-FTIR) spectroscopic technique in combination with a backward Lagrangian stochastic (bLS) dispersion model (WindTrax) can be used to simultaneously measure gaseous emissions of N2O, NH3, CH4 and CO2. We assessed the capability of this technique for measuring NH3 and N2O emissions following the application of calcium nitrate (Ca(NO3)2), Nitrophoska (NPK) and chicken manure on a celery farm at Boneo, Victoria, during April and May 2013. We found that the OP-FTIR/WindTrax method was able to measure the diurnal variation in NH3 flux from the field site following application of chicken manure with measured emissions ranging from approximately 0.1-9.8 kg NH3-N ha-1 day-1. The OP-FTIR/WindTrax method also detected a diurnal variation in N2O flux of 1.5-6.2 kg N2O-N ha-1 day-1 and N2O flux increased in response to application of the Ca(NO3)2. We concluded that the OP-FTIR/WindTrax technique can quantify gaseous N loss from vegetable production systems.

  9. Egg production and associated losses of carbon, nitrogen and fatty acids from maternal biomass in Calanus finmarchicus before the spring bloom

    NASA Astrophysics Data System (ADS)

    Mayor, Daniel J.; Anderson, Thomas R.; Pond, David W.; Irigoien, Xabier

    2009-11-01

    We present concurrent data on ingestion, egg production and the loss of maternal biomass in pre-spring bloom female Calanus finmarchicus incubated under conditions representative of those in situ in the North Atlantic. A balanced metabolic budget was constructed and used to examine the relative importance of ingestion and biomass for fuelling egg production during the incubations. Ingested carbon was not sufficient to meet the observed demands for egg production. More than 80% of the carbon utilised by the females was instead derived from their biomass. Fatty acid analysis demonstrated that the storage reserves, 20:1 ( n-9) and 22:1 ( n-11), were virtually absent before experimentation began, and therefore could not have been used to supply the carbon required for egg production during the incubations. The C:N mass-specific ratio of the biomass utilised was 4.1, suggesting that the females had instead catabolised protein in order to meet their metabolic demands. These results suggest that C. finmarchicus adopts a sacrificial reproductive strategy when food availability is low.

  10. Effect of drying-wetting cycles on leaching behavior of cement solidified lead-contaminated soil.

    PubMed

    Li, Jiang-Shan; Xue, Qiang; Wang, Ping; Li, Zhen-Ze; Liu, Lei

    2014-12-01

    Lead contaminated soil was treated by different concentration of ordinary Portland cement (OPC). Solidified cylindrical samples were dried at 40°C in oven for 48 h subsequent to 24h of immersing in different solution for one drying-wetting. 10 cycles were conducted on specimens. The changes in mass loss of specimens, as well as leaching concentration and pH of filtered leachates were studied after each cycle. Results indicated that drying-wetting cycles could accelerate the leaching and deterioration of solidified specimens. The cumulative leached lead with acetic acid (pH=2.88) in this study was 109, 83 and 71 mg respectively for solidified specimens of cement-to-dry soil (C/Sd) ratios 0.2, 0.3 and 0.4, compared to 37, 30, and 25mg for a semi-dynamic leaching test. With the increase of cycle times, the cumulative mass loss of specimens increased linearly, but pH of filtered leachates decreased. The leachability and deterioration of solidified specimens increased with acidity of solution. Increases of C/Sd clearly reduced the leachability and deterioration behavior.

  11. Study of the Dissolution Behavior of Muscovite in Stone Coal by Oxygen Pressure Acid Leaching

    NASA Astrophysics Data System (ADS)

    Xue, Nan-nan; Zhang, Yi-min; Liu, Tao; Huang, Jing

    2016-02-01

    The dissolution behavior of muscovite in stone coal during the oxygen pressure acid leaching process was studied. The study showed that the dissolution behaviors of V, Al, and K were similar. K was the most easily leached, followed by Al, and then by V during oxygen pressure acid leaching process. When the reaction temperature exceeded 423 K (150 °C), alunite was generated, which led to vanadium losses because of its absorption performance. The dissolution of the muscovite in stone coal mainly depended on H2SO4 concentration and temperature. O2 had a main effect not on muscovite's dissolution but on the V3+ oxidation. During the oxygen pressure acid leaching process, (1) the interfacial K in the muscovite lattice was dissolved rapidly, producing a new interface; (2) for charge balance, the interfacial O absorbed hydrogen ions to form hydroxy; (3) the interfacial hydroxy reacted with hydrogen ions and left vacancy as a result of O loss, producing more new surface to expose more Al, V, and Si; (4) the interfacial Al or V was exchanged by hydrogen ions and V3+ was oxidized to V4+ and V5+; and (5) Si hardly reacted with H+ and generated high-Si surface.

  12. Nitrate-nitrogen and oxygen isotope ratios for identification of nitrate sources and dominant nitrogen cycle processes in a tile-drained dryland agricultural field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural systems are a leading source of reactive nitrogen to aquatic and atmospheric ecosystems. Natural d15Nnitrate and d18Onitrate are used to identify the dominant nitrogen cycle processes and sources of NO3- leached from a tile-drained, dryland agricultural field. Tile-drain water discharge...

  13. Modelling of adaptation processes of crops to water and nitrogen stress

    NASA Astrophysics Data System (ADS)

    Kovacs, G. J.

    2003-04-01

    In the early 1980-es the author published interpretations of his observations on special adaptation processes of crops. Those days it was not yet timely to include these details into a crop model. The knowledge has grown about the systems of crops and their environment, now it is appropriate to build these into systems models. From practical reasons 4M system model was chosen for this work. 4M has been developed at RISSAC, Budapest, Hungary based on CERES model and the advices of J.T. Ritchie. It includes the work of several Hungarian scientists. The newly modelled processes were as follows: (1) nitrate and ammonium concentration of soil solution in soil layers influenced by water transport processes and nitrogen transformation and transport processes, (2) root growth and distribution by the influence of available soil water and soil nitrogen, (3) changed transpiration rate influenced by radical change of availability of nitrogen. (4) changed distribution rate and redistribution of dry matter and nutrients in plants influenced by water and nitrogen stress. These processes have different consequences in the plant production depending on the phenological stage when the stress occurs. There are weather situations under the climate of the Carpathian base under which these the summer stress reactions can cause tons of losses in biomass and yield despite of abundant supply of fertilizers in spring. The phenomena can be characterised as spoiled maize stand interrupted by a heavy rainy period with strong nitrate leaching. In the dry period after the rainy period nitrogen shortage intensifies transpiration then the lack of water supply makes the plant to grow the roots fast in the deeper horizons. That leads to redistribution of biomass, loss of above ground DM, and deficiency of nutrients in the plant. In flowering stage it may lead to poor fertilization and smaller grain numbers consequently lower yield potential.

  14. Carbon and nitrogen cycles in European ecosystems respond differently to global warming.

    PubMed

    Beier, C; Emmett, B A; Peñuelas, J; Schmidt, I K; Tietema, A; Estiarte, M; Gundersen, P; Llorens, L; Riis-Nielsen, T; Sowerby, A; Gorissen, A

    2008-12-15

    The global climate is predicted to become significantly warmer over the next century. This will affect ecosystem processes and the functioning of semi natural and natural ecosystems in many parts of the world. However, as various ecosystem processes may be affected to a different extent, balances between different ecosystem processes as well as between different ecosystems may shift and lead to major unpredicted changes. In this study four European shrubland ecosystems along a north-south temperature gradient were experimentally warmed by a novel nighttime warming technique. Biogeochemical cycling of both carbon and nitrogen was affected at the colder sites with increased carbon uptake for plant growth as well as increased carbon loss through soil respiration. Carbon uptake by plant growth was more sensitive to warming than expected from the temperature response across the sites while carbon loss through soil respiration reacted to warming in agreement with the overall Q10 and response functions to temperature across the sites. Opposite to carbon, the nitrogen mineralization was relatively insensitive to the temperature increase and was mainly affected by changes in soil moisture. The results suggest that C and N cycles respond asymmetrically to warming, which may lead to progressive nitrogen limitation and thereby acclimation in plant production. This further suggests that in many temperate zones nitrogen deposition has to be accounted for, not only with respect to the impact on water quality through increased nitrogen leaching where N deposition is high, but also in predictions of carbon sequestration in terrestrial ecosystems under future climatic conditions. Finally the results indicate that on the short term the above-ground processes are more sensitive to temperature changes than the below ground processes.

  15. Process for the leaching of AP from propellant

    NASA Technical Reports Server (NTRS)

    Shaw, G. C.; Mcintosh, M. J. (Inventor)

    1980-01-01

    A method for the recovery of ammonium perchlorate from waste solid rocket propellant is described wherein shredded particles of the propellant are leached with an aqueous leach solution containing a low concentration of surface active agent while stirring the suspension.

  16. Leaching and Root Zone Salinity Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A detailed description of the salt balance index is provided with a discussion related to individual components and their importance in calculating the index. Major sources identified are fertilizers, geologic sources, irrigation water, and rainfall in specific areas. The concept of leaching fract...

  17. Duality properties of Gorringe Leach equations

    NASA Astrophysics Data System (ADS)

    Grandati, Yves; Bérard, Alain; Mohrbach, Hervé

    2009-02-01

    In the category of motions preserving the angular momentum direction, Gorringe and Leach exhibited two classes of differential equations having elliptical orbits. After enlarging slightly these classes, we show that they are related by a duality correspondence of the Arnold Vassiliev type. The specific associated conserved quantities (Laplace Runge Lenz vector and Fradkin Jauch Hill tensor) are then dual reflections of each other.

  18. Leaching of toluene-neoprene adhesive wastes.

    PubMed

    Font, R; Sabater, M C; Martínez, M A

    2001-03-01

    This work consists of the study of the extraction of solvent (toluene) from a polymeric (neoprene) substrate during a leaching process. Total organic carbon (TOC) is the main contaminant parameter in the leaching of these systems due to the solution of the toluene and the dispersion of the polymer. The toxicity of the extracts was measured with a Microtox equipment, using Photobacteria phosphoreum, deducing that the toxicity of the extracts is low due to the low solubility of toluene but that the toxicity of toluene is high. On the basis of the experimental results, the amount of toluene diffused vs time in plane sheet systems was studied. A kinetic model has been developed considering two stages: In the first stage, the toluene diffuses into the system across the neoprene chains at a constant rate, not depending on the initial toluene concentration. This fact is explained by considering that there is a constant difference of the toluene concentration between the interface with the water and the inner part of the sample. In the second stage, the dispersion of the polymer with the corresponding amount of toluene takes place. The diffusion of toluene in the leaching process is compared and analyzed considering the diffusion of toluene in a desorption process in air so that the difference of toluene concentration between the interface and the interior can be estimated. A mathematical model is also proposed for considering the leaching process in other operating conditions.

  19. Chalcopyrite leaching: The rate controlling factors

    NASA Astrophysics Data System (ADS)

    Li, J.; Kawashima, N.; Kaplun, K.; Absolon, V. J.; Gerson, A. R.

    2010-05-01

    The processes that determine the rate of chalcopyrite leaching are central to understanding how chalcopyrite (CuFeS 2) behaves under the environmentally adverse conditions of acid rock drainage. To this end the effect of the acid anion on chalcopyrite leach rates using a variety of acidic media (H 2SO 4, HClO 4, HCl and H 2SO 4 with 0.25 M NaCl) under carefully controlled solution conditions (pH 1 and 2, Eh 750 mV (SHE) and 75 °C) has been examined. These conditions have been chosen to enable sufficient leach rates for accurate experimental determination and to compare to the previous mechanistic analysis carried out by Harmer et al. (2006). Extensive surface analysis of leach residues demonstrated that variations in the surface speciation could not be responsible for the observed variations in leach rate. The rate of Cu release, however, was found to be first order with respect to Fe 3+ activity and inversely proportional with respect to H + activity to the power of 0.7: {1}/{S}{dC}/{dt}=(2.0±0.2){a}/{aH0.7} where S is the relative surface area, C is concentration of Cu in the solution (M), t is the time (h), 2.0 is the rate constant (M 0.7 h -1) and a and a are Fe 3+ and H + activities, respectively (M). The rate model was further validated against additional leaches carried out in H 2SO 4 media with the initial addition of Fe 3+ (8 mM as Fe 2(SO 4) 3) at 75 °C under various pH and Eh regimes. The only condition under which this rate model was found not to hold was at simultaneously low a and high a, that is at pH 1 and a<5×10-5M, where the concentration of dissolved O 2 may be leach rate determining.

  20. Ecological Engineering Practices for the Reduction of Excess Nitrogen in Human-Influenced Landscapes: A Guide for Watershed Managers

    EPA Science Inventory

    Excess nitrogen (N) in freshwater systems, estuaries, and coastal areas has well-documented deleterious effects on ecosystems. Ecological engineering practices (EEPs) may be effective at decreasing nonpoint source N leaching to surface and groundwater. However, few studies have s...

  1. Leaching Pretreatments for Improving Biomass Quality: Feedstocks, Solvents, and Extraction Modeling

    NASA Astrophysics Data System (ADS)

    Yu, Chao Wei

    In this research, a systematic study was conducted to quantify the inorganic and organic compounds leached from rice straw, wheat straw, corn stover, switchgrass, Jose Tall Wheatgrass, Douglas fir, and Miscanthus with water, and to evaluate the feedstock quality and characteristics of leached solids for thermal process applications. Leaching feedstocks with water at ambient temperature with a 20 L/kg (dry matter) ratio for 2 hours greatly increased the ash fusion temperature of rice straw (from 1050°C to above 1550°C) and wheat straw (from 900°C to 1250°C), but the treatment only increased the ash fusion temperature of corn stover from 900°C to 950°C. Miscanthus had relatively good initial feedstock quality and leaching may not prove necessary for this feedstock in thermal systems. Leaching also changed the combustion kinetics of biomass by increasing the initial degradation temperature of most feedstocks from originally between 165°C and 186°C to between 180°C and 250°C depending on feedstock. Moreover, leaching increased the maximum rate of weight loss of feedstock by 11% to 54% and increased the corresponding temperatures for peak loss up to 34°C. Leaching removed a sizeable fraction of organic compounds (between 2% and 12% of dry matter). These organic extracts were identified as mostly sugars and acids which might be valuable co-products. Moisture contents of feedstocks after leaching were typically high, ranging between 68 and 81% wet basis. A dewatering step is generally required prior to using the leached biomass for thermochemical conversion. Solvents with ability to dissolve ion-exchangeable, organically associated, and acid soluble metals can further remove non-water soluble metals from biomass and may also improve feedstock quality. In a solvent evaluation, corn stover and wheat straw were leached with water, 1M ammonium acetate, 1M HCl, 100% methanol, 50% methanol, 100% ethanol, and 50% ethanol, and leached solids and leachate were

  2. Leaching of Mixtures of Biochar and Fly Ash

    SciTech Connect

    Palumbo, Anthony Vito; Porat, Iris; Phillips, Jana Randolph; Amonette, J. E.; Drake, Meghan M; Brown, Steven D; Schadt, Christopher Warren

    2009-01-01

    Increasing atmospheric levels of greenhouse gases, especially CO2, and their effects on global temperature have led to interest in the possibility of carbon storage in terrestrial environments.2, 5, 6 Both the residual char from biomass pyrolysis7-9, 12 (biochar) and fly ash from coal combustion1, 13, 14 have the potential to significantly expand terrestrial sequestration options. Both biochar and fly ash also have potentially beneficial effects on soil properties. Fly ash has been shown to increase porosity, water-holding capacity, pH, conductivity, and dissolved SO42-, CO32-, Cl- and basic cations.10, 11, 16 Adding biochar to soil generally raises pH, increases total nitrogen and total phosphorous, encourages greater root development, improves cation exchange capacity and reduces available aluminum.3, 17 Combinations of these benefits likely lead to the observed increased yields for crops including corn and sugarcane.17 with biochar addition to soil. In addition, it has been found that soils with added biochar emit lower amounts of other greenhouse gases (methane and nitrous oxide) 8, 17 than do unammended soils. Biochar and fly ash amendments may be useful in promoting terrestrial carbon sequestration on currently underutilized and degraded lands. For example, about 1% of the US surface lands consist of previously mined lands or highway rights-of-way.18 Poorly managed lands could count for another 15% of US area. Biochar and fly ash amendments could increase productivity of these lands and increase carbon storage in the soil Previous results showed minimal leaching of organic carbon and metals from a variety of fly ashes.15 Here, we are examining the properties of mixtures of biochar, fly ash, and soil and evaluating leaching of organic carbon and metals from the mixtures.

  3. P losses in soil columns amended with compost and digestate from municipal solid wastes

    NASA Astrophysics Data System (ADS)

    García-Albacete, Marta; Cartagena, M. Carmen

    2013-04-01

    Sludge's, manures and compost applied to agricultural soils in high quantities and long-term application to increase crop productivity, result in accumulation of soil phosphorous (P). Soluble P is directly available to algae (Sonzogni et al., 1982) and thus particularly relevant to water quality degradation. Transport of P from agricultural soils to surface waters has been linked to eutrophication in fresh water and estuaries (Sharpley and Lemunyon, 1998). Almost 50% of stored water in Spain is degraded by eutrophication processes that cause the proliferation of algae and other organisms and a decrease in oxygen content (Environmental Profile of Spain 2005). Fertilizers and biodegradable wastes application rates in agriculture are based on nitrogen requirements. This results in a P supply that is in excess of crops needs since the ratio of P to N in waste use to be greater than required by plants (Smith, 1995). While surface runoff is an important pathway of phosphorus losses from agricultural lands, significant losses can also occur via leaching thought soils. Leaching tests are important for assessing the risk of release of potential pollutants from biodegradable wastes into groundwater or surface water. Percolation tests also get information about the interaction of organic waste with soils. The study was conducted according to the percolation leaching test CEN/TS 14405 "Characterization of waste-Leaching behavior test- Up-flow percolation test" with three different soils mixed with organic wastes from msw (compost and digestato) and an inorganic fertilizer (NaH2PO4). Each soil was amended with the P sources at rates of 100 kg P ha-1. Leachates were collected and analyzed for each column for dissolved reactive P by inductively coupled plasma atomic emission spectroscopy (ICP) following USEPA Method 3050A digestion (USEPA, 1995). The fact that P sorption capacity (Xmax, PSI) of the soils was determined using Langmuiŕs isotherms and the P forms from organic

  4. An integrated study of nutrient leaching and greenhouse gas emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient leaching and greenhouse gas emission are two of the primary environmental impacts of crop production. These processes have been studied at great length separately, but few integrated studies of leaching and greenhouse gas emission have been conducted. We measured nutrient leaching and green...

  5. Land application of domestic effluent onto four soil types: plant uptake and nutrient leaching.

    PubMed

    Barton, L; Schipper, L A; Barkle, G F; McLeod, M; Speir, T W; Taylor, M D; McGill, A C; van Schaik, A P; Fitzgerald, N B; Pandey, S P

    2005-01-01

    Land application has become a widely applied method for treating wastewater. However, it is not always clear which soil-plant systems should be used, or why. The objectives of our study were to determine if four contrasting soils, from which the pasture is regularly cut and removed, varied in their ability to assimilate nutrients from secondary-treated domestic effluent under high hydraulic loadings, in comparison with unirrigated, fertilized pasture. Grassed intact soil cores (500 mm in diameter by 700 mm in depth) were irrigated (50 mm wk(-1)) with secondary-treated domestic effluent for two years. Soils included a well-drained Allophanic Soil (Typic Hapludand), a poorly drained Gley Soil (Typic Endoaquept), a well-drained Pumice Soil formed from rhyolitic tephra (Typic Udivitrand), and a well-drained Recent Soil formed in a sand dune (Typic Udipsamment). Effluent-irrigated soils received between 746 and 815 kg N ha(-1) and 283 and 331 kg P ha(-1) over two years of irrigation, and unirrigated treatments received 200 kg N ha(-1) and 100 kg P ha(-1) of dissolved inorganic fertilizer over the same period. Applying effluent significantly increased plant uptake of N and P from all soil types. For the effluent-irrigated soils plant N uptake ranged from 186 to 437 kg N ha(-1) yr(-1), while plant P uptake ranged from 40 to 88 kg P ha(-1) yr(-1) for the effluent-irrigated soils. Applying effluent significantly increased N leaching losses from Gley and Recent Soils, and after two years ranged from 17 to 184 kg N ha(-1) depending on soil type. Effluent irrigation only increased P leaching from the Gley Soil. All P leaching losses were less than 49 kg P ha(-1) after two years. The N and P leached from effluent treatments were mainly in organic form (69-87% organic N and 35-65% unreactive P). Greater N and P leaching losses from the irrigated Gley Soil were attributed to preferential flow that reduced contact between the effluent and the soil matrix. Increased N leaching from

  6. Modeling nitrogen fluxes in Germany - where does the nitrogen go?

    NASA Astrophysics Data System (ADS)

    Klement, Laura; Bach, Martin; Breuer, Lutz

    2016-04-01

    According to the latest inventory of the EU Water Framework Directive, 26.3% of German groundwater bodies are in a poor chemical state regarding nitrate. Additionally, the EU initiated infringement proceedings against Germany for not meeting the quality standards of the EU Nitrate Directive. Agriculture has been determined as the main source of nitrate pollution due to over-fertilization and regionally high density of livestock farming. The nitrogen balance surplus is commonly used as an indicator characterizing the potential of nitrate leaching into groundwater bodies and thus also serves as a foundation to introduce legislative restrictions or to monitor the success of mitigation measures. Currently, there is an ongoing discussion which measures are suitable for reducing the risk of nitrate leaching and also to what extent. However, there is still uncertainty about just how much the nitrogen surplus has to be reduced to meet the groundwater quality standards nationwide. Therefore, the aims of our study were firstly to determine the level of the nitrogen surplus that would be acceptable at the utmost and secondly whether the currently discussed target value of 30 kg N per hectare agricultural land for the soil surface nitrogen balance would be sufficient. The models MONERIS (Modeling Nutrient Emissions in River System) and MoRE (Modelling of Regionalized Emissions), the latter based on the first, are commonly used for estimating nitrogen loads into the river system in Germany at the mesoscale, as well as the effect of mitigation measures in the context of the EU directive 2008/105/EC (Environmental quality standards applicable to surface water). We used MoRE to calculate nitrate concentration for 2759 analytical units in Germany. Main factors are the surplus of the soil surface nitrogen balance, the percolation rate and an exponent representing the denitrification in the vadose zone. The modeled groundwater nitrate concentrations did not correspond to the regional

  7. Nitrate Accumulation and Leaching in Surface and Ground Water Based on Simulated Rainfall Experiments.

    PubMed

    Wang, Hong; Gao, Jian-en; Li, Xing-hua; Zhang, Shao-long; Wang, Hong-jie

    2015-01-01

    To evaluate the process of nitrate accumulation and leaching in surface and ground water, we conducted simulated rainfall experiments. The experiments were performed in areas of 5.3 m2 with bare slopes of 3° that were treated with two nitrogen fertilizer inputs, high (22.5 g/m2 NH4NO3) and control (no fertilizer), and subjected to 2 hours of rainfall, with. From the 1st to the 7th experiments, the same content of fertilizer mixed with soil was uniformly applied to the soil surface at 10 minutes before rainfall, and no fertilizer was applied for the 8th through 12th experiments. Initially, the time-series nitrate concentration in the surface flow quickly increased, and then it rapidly decreased and gradually stabilized at a low level during the fertilizer experiments. The nitrogen loss in the surface flow primarily occurred during the first 18.6 minutes of rainfall. For the continuous fertilizer experiments, the mean nitrate concentrations in the groundwater flow remained at less than 10 mg/L before the 5th experiment, and after the 7th experiment, these nitrate concentrations were greater than 10 mg/L throughout the process. The time-series process of the changing concentration in the groundwater flow exhibited the same parabolic trend for each fertilizer experiment. However, the time at which the nitrate concentration began to change lagged behind the start time of groundwater flow by approximately 0.94 hours on average. The experiments were also performed with no fertilizer. In these experiments, the mean nitrate concentration of groundwater initially increased continuously, and then, the process exhibited the same parabolic trend as the results of the fertilization experiments. The nitrate concentration decreased in the subsequent experiments. Eight days after the 12 rainfall experiments, 50.53% of the total nitrate applied remained in the experimental soil. Nitrate residues mainly existed at the surface and in the bottom soil layers, which represents a

  8. Nitrate Accumulation and Leaching in Surface and Ground Water Based on Simulated Rainfall Experiments

    PubMed Central

    Wang, Hong; Gao, Jian-en; Li, Xing-hua; Zhang, Shao-long; Wang, Hong-jie

    2015-01-01

    To evaluate the process of nitrate accumulation and leaching in surface and ground water, we conducted simulated rainfall experiments. The experiments were performed in areas of 5.3 m2 with bare slopes of 3° that were treated with two nitrogen fertilizer inputs, high (22.5 g/m2 NH4NO3) and control (no fertilizer), and subjected to 2 hours of rainfall, with. From the 1st to the 7th experiments, the same content of fertilizer mixed with soil was uniformly applied to the soil surface at 10 minutes before rainfall, and no fertilizer was applied for the 8th through 12th experiments. Initially, the time-series nitrate concentration in the surface flow quickly increased, and then it rapidly decreased and gradually stabilized at a low level during the fertilizer experiments. The nitrogen loss in the surface flow primarily occurred during the first 18.6 minutes of rainfall. For the continuous fertilizer experiments, the mean nitrate concentrations in the groundwater flow remained at less than 10 mg/L before the 5th experiment, and after the 7th experiment, these nitrate concentrations were greater than 10 mg/L throughout the process. The time-series process of the changing concentration in the groundwater flow exhibited the same parabolic trend for each fertilizer experiment. However, the time at which the nitrate concentration began to change lagged behind the start time of groundwater flow by approximately 0.94 hours on average. The experiments were also performed with no fertilizer. In these experiments, the mean nitrate concentration of groundwater initially increased continuously, and then, the process exhibited the same parabolic trend as the results of the fertilization experiments. The nitrate concentration decreased in the subsequent experiments. Eight days after the 12 rainfall experiments, 50.53% of the total nitrate applied remained in the experimental soil. Nitrate residues mainly existed at the surface and in the bottom soil layers, which represents a

  9. Modeling sustainable reuse of nitrogen-laden wastewater by poplar.

    PubMed

    Wang, Yusong; Licht, Louis; Just, Craig

    2016-01-01

    Numerical modeling was used to simulate the leaching of nitrogen (N) to groundwater as a consequence of irrigating food processing wastewater onto grass and poplar under various management scenarios. Under current management practices for a large food processor, a simulated annual N loading of 540 kg ha(-1) yielded 93 kg ha(-1) of N leaching for grass and no N leaching for poplar during the growing season. Increasing the annual growing season N loading to approximately 1,550 kg ha(-1) for poplar only, using "weekly", "daily" and "calculated" irrigation scenarios, yielded N leaching of 17 kg ha(-1), 6 kg ha(-1), and 4 kg ha(-1), respectively. Constraining the simulated irrigation schedule by the current onsite wastewater storage capacity of approximately 757 megaliters (Ml) yielded N leaching of 146 kg ha(-1) yr(-1) while storage capacity scenarios of 3,024 and 4,536 Ml yielded N leaching of 65 and 13 kg ha(-1) yr(-1), respectively, for a loading of 1,550 kg ha(-1) yr(-1). Further constraining the model by the current wastewater storage volume and the available land area (approximately 1,000 hectares) required a "diverse" irrigation schedule that was predicted to leach a weighted average of 13 kg-N ha(-1) yr(-1) when dosed with 1,063 kg-N ha(-1) yr(-1).

  10. Modeling the effects of different N fertilizer rates on N2O emissions and nitrate leaching from arable soils in Korea

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Berger, S.; Tenhunen, J. D.; Gebauer, G.; Kiese, R.

    2012-12-01

    Process-based biogeochemical models can be used to predict the impact of various agricultural management practices on plant nitrogen use efficiency and nitrogen losses to the environment such as greenhouse gas emissions and nitrate leaching by analyzing the interactions between management practices, primary drivers such as climate, soil properties, crop types, etc., and biogeochemical reactions. In this study we applied the Landscape-DNDC model, which combines and uniforms functions of the agricultural-DNDC and the Forest-DNDC for simulation of C and N turnover, GHG emissions, nitrate leaching, and plant growth for a Korean arable field cultivated with radish (Raphanus sativus L.). The annual average temperature is app. 8.5°C and the annual precipitation is app. 1,500 mm. According to farmers practice the study field received a basal fertilizer application of app. 200 kg N ha-1 before setting up four fertilizer treatments i.e. additionally 50, 150, 250 and 350 kg N ha-1. All N treatment plots were tilled a week after application of specific N fertilizer in order to make row and interrow. Just before radish seeding rows were covered with black plastic mulch which was removed after harvest. In spite the widespread usage of black mulch in Korea or even Asia; so far biogeochemical models do not consider impacts of mulch on soil environmental conditions and soil biogeochemistry. Based on field measurements we adjusted input information and used only half of the annual precipitation and the maximum temperature for simulation of row conditions, whereas the actual weather data were used for the interrow simulations. Simulated N2O emissions agreed well with measurements; however peak emissions after fertilization were slightly underestimated in row and interrow. Annual N2O emissions of the fertilizer treatments increased with increasing fertilization rates from around 1.5 to 3 kg N ha-1 in the row and lower emissions of app. 1.5 kg N ha-1 (for all N treatments) in the

  11. Radiological investigation of phosphate fertilizers: Leaching studies.

    PubMed

    Hegedűs, Miklós; Tóth-Bodrogi, Edit; Németh, Szabolcs; Somlai, János; Kovács, Tibor

    2016-10-19

    The raw materials of the phosphate fertilizer industry are the various apatite minerals. Some of these have high levels of natural radionuclides, and thus phosphate fertilizers contain significant amounts of U-238, K-40 and Ra-226. These can leach out of the fertilizers used in large quantities for resupplying essential nutrients in the soil and can then enter the food chain through plants, thereby increasing the internal dose of the affected population. In the current study, the radiological risk of eight commercially available phosphate fertilizers (superphosphate, NPK, PK) and their leaching behaviours were investigated using different techniques (gamma and alpha spectrometry), and the dose contributions of using these fertilizers were estimated. To characterize the leaching behaviour, two leaching procedures were applied and compared -the MSZ 21470-50 (Hungarian standard) and the Tessier five-step sequential extraction method. Based on the evaluation of the gamma-spectra, it is found that the level of Th-232 in the samples was low (max.7 ± 6 Bq kg(-1)), the average Ra-226 activity concentration was 309 ± 39 Bq kg(-1) (min. 10 ± 8 Bq kg(-1), max. 570 ± 46 Bq kg(-1)), while the K-40 concentrations (average 3139 ± 188 Bq kg(-1), min. 51 ± 36 Bq kg(-1)) could be as high as 7057 ± 427 Bq kg(-1). The high K-40 can be explained by reference to the composition of the investigated fertilizers (NPK, PK). U concentrations were between 15 and 361 Bq kg(-1), with the average of 254 Bq kg(-1), measured using alpha spectrometry. The good correlation between P2O5 content and radioactivity reported previously is not found in our data. The leaching studies reveal that the mobility of the fertilizer's uranium content is greatly influenced by the parameters of the leaching methods. The availability of U to water ranged between 3 and 28 m/m%, while the Lakanen-Erviö solution mobilized between 10 and 100% of the U content.