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Sample records for agricultural soil carbon

  1. Soil Organic Carbon dynamics in agricultural soils of Veneto Region

    NASA Astrophysics Data System (ADS)

    Bampa, F. B.; Morari, F. M.; Hiederer, R. H.; Toth, G. T.; Giandon, P. G.; Vinci, I. V.; Montanarella, L. M.; Nocita, M.

    2012-04-01

    One of the eight soil threats expressed in the European Commission's Thematic Strategy for Soil Protection (COM (2006)231 final) it's the decline in Soil Organic Matter (SOM). His preservation is recognized as with the objective to ensure that the soils of Europe remain healthy and capable of supporting human activities and ecosystems. One of the key goals of the strategy is to maintain and improve Soil Organic Carbon (SOC) levels. As climate change is identified as a common element in many of the soil threats, the European Commission (EC) intends to assess the actual contribution of the soil protection to climate change mitigation and the effects of climate change on the possible depletion of SOM. A substantial proportion of European land is occupied by agriculture, and consequently plays a crucial role in maintaining natural resources. Organic carbon preservation and sequestration in the EU's agricultural soils could have some potential to mitigate the effects of climate change, particularly linked to preventing certain land use changes and maintaining SOC stocks. The objective of this study is to assess the SOC dynamics in agricultural soils (cropland and grassland) at regional scale, focusing on changes due to land use. A sub-objective would be the evaluation of the most used land management practices and their effect on SOC content. This assessment aims to determine the geographical distribution of the potential GHG mitigation options, focusing on hot spots in the EU, where mitigation actions would be particularly efficient and is linked with the on-going work in the JRC SOIL Action. The pilot area is Veneto Region. The data available are coming from different sources, timing and involve different variables as: soil texture, climate, soil disturbance, managements and nutrients. The first source of data is the LUCAS project (Land Use/Land Cover Area Frame statistical Survey). Started in 2001, the LUCAS project aims to monitor changes in land cover/use and

  2. Soil biology and carbon in dryland agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this paper is to explore potential management strategies in dryland agriculture that can promote soil health and crop productivity. Traditional crop production in the semiarid Great Plains consists of conventional tillage management of winter wheat (Triticum aestivum L.) - summer fallow....

  3. Does North Appalachian Agriculture Contribute to Soil Carbon Sequestration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural systems are important for world ecosystems. They can be managed to moderate CO2 emissions. World soils can be both a sink and source of atmospheric CO2, but it is a slow process. Data from long-term soil management experiments are needed to assess soil carbon (C) sink capacity through a...

  4. The carbon balance of U.S. agricultural soils

    NASA Astrophysics Data System (ADS)

    Paustian, K.; Williams, S.

    2001-05-01

    Carbon inputs through crop residues are one of the main determinants of soil carbon levels and carbon sequestration potentials in cropland soils. We estimated C inputs to U.S. agricultural soils at the county level, over the past 100 years, using a variety of agricultural databases and literature sources. Crop acreage and production estimates, available at the county level through the National Agricultural Statistics Service (NASS-USDA), were used to estimate crop residues. Continuous county values exist from circa 1920 to the present. State level data on acreage and yields of several major crops (corn, wheat, oats, etc.) are available from 1866 through the present. Analogous data from NASS and the Agricultural Census on animal type and numbers were used to estimate animal manure inputs. To estimate C inputs from yields, data from over 125 published works were used to determine regression estimates for grain to aboveground residue ratios, root biomass to aboveground biomass ratios, and estimates of root-derived carbon due to exudation and root sloughing. Where possible, the regressions included changes in these ratios through time as a result of the introduction of new cultivars or new cropping practices. Patterns of carbon inputs over time, and their geographic distribution, are compared with the geographic distribution of present-day soil C stocks on agricultural lands derived from soil maps and pedon data. Predictions of the equilibrium C levels that could be attained under the current levels of carbon input to cropland soils are compared for alternative models of soil organic matter kinetics.

  5. Carbon isotope fractionation of methyl bromide during agricultural soil fumigations

    USGS Publications Warehouse

    Bill, M.; Miller, L.G.; Goldstein, Allen H.

    2002-01-01

    The isotopic composition of methyl bromide (CH3Br) has been suggested to be a potentially useful tracer for constraining the global CH3Br budget. In order to determine the carbon isotopic composition of CH3Br emitted from the most significant anthropogenic application (pre-plant fumigation) we directly measured the ??13C of CH3Br released during commercial fumigation. We also measured the isotopic fractionation associated with degradation in agricultural soil under typical field fumigation conditions. The isotopic composition of CH3Br collected in soil several hours after injection of the fumigant was -44.5??? and this value increased to -20.7??? over the following three days. The mean kinetic isotope effect (KIE) associated with degradation of CH3Br in agricultural soil (12???) was smaller than the reported value for methylotrophic bacterial strain IMB-1, isolated from previously fumigated agricultural soil, but was similar to methylotrophic bacterial strain CC495, isolated from a pristine forest litter zone. Using this fractionation associated with the degradation of CH3Br in agricultural soil and the mean ??13C of the industrially manufactured CH3Br (-54.4???), we calculate that the agricultural soil fumigation source has a carbon isotope signature that ranges from -52.8??? to -42.0???. Roughly 65% of industrially manufactured CH3Br is used for field fumigations. The remaining 35% is used for structural and post-harvest fumigations with a minor amount used during industrial chemical manufacturing. Assuming that the structural and post-harvest fumigation sources of CH3Br are emitted without substantial fractionation, we calculate that the ??13C of anthropogenically emitted CH3Br ranges from -53.2??? to -47.5???.

  6. Sampling for Soil Carbon Stock Assessment in Rocky Agricultural Soils

    NASA Technical Reports Server (NTRS)

    Beem-Miller, Jeffrey P.; Kong, Angela Y. Y.; Ogle, Stephen; Wolfe, David

    2016-01-01

    Coring methods commonly employed in soil organic C (SOC) stock assessment may not accurately capture soil rock fragment (RF) content or soil bulk density (rho (sub b)) in rocky agricultural soils, potentially biasing SOC stock estimates. Quantitative pits are considered less biased than coring methods but are invasive and often cost-prohibitive. We compared fixed-depth and mass-based estimates of SOC stocks (0.3-meters depth) for hammer, hydraulic push, and rotary coring methods relative to quantitative pits at four agricultural sites ranging in RF content from less than 0.01 to 0.24 cubic meters per cubic meter. Sampling costs were also compared. Coring methods significantly underestimated RF content at all rocky sites, but significant differences (p is less than 0.05) in SOC stocks between pits and corers were only found with the hammer method using the fixed-depth approach at the less than 0.01 cubic meters per cubic meter RF site (pit, 5.80 kilograms C per square meter; hammer, 4.74 kilograms C per square meter) and at the 0.14 cubic meters per cubic meter RF site (pit, 8.81 kilograms C per square meter; hammer, 6.71 kilograms C per square meter). The hammer corer also underestimated rho (sub b) at all sites as did the hydraulic push corer at the 0.21 cubic meters per cubic meter RF site. No significant differences in mass-based SOC stock estimates were observed between pits and corers. Our results indicate that (i) calculating SOC stocks on a mass basis can overcome biases in RF and rho (sub b) estimates introduced by sampling equipment and (ii) a quantitative pit is the optimal sampling method for establishing reference soil masses, followed by rotary and then hydraulic push corers.

  7. A simple model of carbon in the soil profile for agricultural soils in Northwestern Europe

    NASA Astrophysics Data System (ADS)

    Taghizadeh-Toosi, Arezoo; Hutchings, Nicholas J.; Vejlin, Jonas; Christensen, Bent T.; Olesen, Jørgen E.

    2014-05-01

    World soil carbon (C) stocks are second to those in the ocean, and represent three times as much C as currently present in the atmosphere. The amount of C in soil may play a significant role in carbon exchanges between the atmosphere and the terrestrial environment. The C-TOOL model is a three-pool linked soil organic carbon (SOC) model in well-drained mineral soils under agricultural land management to allow generalized parameterization for estimating effects of management measures at medium to long time scales for the entire soil profile (0-100 cm). C-TOOL has been developed to enable simulations of SOC turnover in soil using temperature dependent first order kinetics for describing decomposition. Compared with many other SOC models, C-TOOL applies a less complicated structure, which facilitates easier calibration, and it requires only few inputs (i.e., average monthly air temperature, soil clay content,soil carbon-to-nitrogen ratio, and C inputs to the soil from plants and other sources). C-TOOL was parameterized using SOC and radiocarbon data from selected long-term field treatments in United Kingdom, Sweden and Denmark. However, less data were available for evaluation of subsoil C (25-100 cm) from the long-term experiments applied. In Denmark a national 7×7 km grid net was established in 1986 for soil C monitoring down to 100 cm depth. The results of SOC showed a significant decline from 1997 to 2009 in the 0-50 cm soil layer. This was mainly attributed to changes in the 25-50 cm layer, where a decline in SOC was found for all soil texture types. Across the period 1986 to 2009 there was clear tendency for increasing SOC on the sandy soils and reductions on the loamy soils. This effect is linked to land use, since grasslands and dairy farms are more abundant in the western parts of Denmark, where most of the sandy soils are located. The results and the data from soil monitoring have been used to validate the C-TOOL modelling approach used for accounting of

  8. Soil organic carbon fractionation for improving agricultural soil quality diagnosis in different management practices.

    NASA Astrophysics Data System (ADS)

    Trigalet, Sylvain; Chartin, Caroline; Kruger, Inken; Carnol, Monique; Van Oost, Kristof; van Wesemael, Bas

    2016-04-01

    Preserving ecosystem functions of soil organic matter (SOM) in soils is a key challenge. The need for an efficient diagnosis of SOM state in agricultural soils is a priority in order to facilitate the detection of changes in soil quality as a result of changes in management practices. The nature of SOM is complex and cannot readily be monitored due to the heterogeneity of its components. Assessment of the SOM level dynamics, typically characterized as the bulk soil organic carbon (SOC), can be refined by taking into account carbon pools with different turnover rates and stability. Fractionating bulk SOC in meaningful soil organic fractions helps to better diagnose SOC status. By separating carbon associated with clay and fine silt particles (stable carbon with slow turnover rate) and carbon non-associated with this fraction (labile and intermediate carbon with higher turnover rates), effects of management can be detected more efficiently at different spatial and temporal scales. Until now, most work on SOC fractionation has focused on small spatial scales along management or time gradients. The present case study focuses on SOC fractionation applied in order to refine the interpretation of organic matter turnover and SOC sequestration for regional units in Wallonia with comparable climate, management and, to a certain extent, soil conditions. In each unit, random samples from specific land uses are analyzed in order to assess the Normal Operative Ranges (NOR) of SOC fraction contents for each unit and land use combination. Thus, SOC levels of the different fractions of a specific field in a given unit can be compared to its corresponding NOR. It will help to better diagnose agricultural soil quality in terms of organic carbon compared to a bulk SOC diagnosis.

  9. Modelling the effect of agricultural management practices on soil organic carbon stocks: does soil erosion matter?

    NASA Astrophysics Data System (ADS)

    Nadeu, Elisabet; Van Wesemael, Bas; Van Oost, Kristof

    2014-05-01

    Over the last decades, an increasing number of studies have been conducted to assess the effect of soil management practices on soil organic carbon (SOC) stocks. At regional scales, biogeochemical models such as CENTURY or Roth-C have been commonly applied. These models simulate SOC dynamics at the profile level (point basis) over long temporal scales but do not consider the continuous lateral transfer of sediment that takes place along geomorphic toposequences. As a consequence, the impact of soil redistribution on carbon fluxes is very seldom taken into account when evaluating changes in SOC stocks due to agricultural management practices on the short and long-term. To address this gap, we assessed the role of soil erosion by water and tillage on SOC stocks under different agricultural management practices in the Walloon region of Belgium. The SPEROS-C model was run for a 100-year period combining three typical crop rotations (using winter wheat, winter barley, sugar beet and maize) with three tillage scenarios (conventional tillage, reduced tillage and reduced tillage in combination with additional crop residues). The results showed that including soil erosion by water in the simulations led to a general decrease in SOC stocks relative to a baseline scenario (where no erosion took place). The SOC lost from these arable soils was mainly exported to adjacent sites and to the river system by lateral fluxes, with magnitudes differing between crop rotations and in all cases lower under conservation tillage practices than under conventional tillage. Although tillage erosion plays an important role in carbon redistribution within fields, lateral fluxes induced by water erosion led to a higher spatial and in-depth heterogeneity of SOC stocks with potential effects on the soil water holding capacity and crop yields. This indicates that studies assessing the effect of agricultural management practices on SOC stocks and other soil properties over the landscape should

  10. Geomorphic Controls of Soil and Carbon Redistribution Across an Agricultural Landscape

    NASA Astrophysics Data System (ADS)

    Ritchie, J. C.; McCarty, G. W.; Venteris, E. R.; Kaspar, T. C.

    2006-12-01

    Patterns of soil organic carbon (SOC) vary widely across the landscape leading to large uncertainties in the SOC budget especially for agricultural landscapes where water, tillage, and wind erosion redistributes soil and SOC. It is often assumed that soil erosion results in a loss of SOC from the agricultural ecosystem but recent studies indicate that soil erosion and its subsequent redistribution within fields can stimulate SOC sequestration in agricultural fields. This study investigates the relationship between soil and SOC redistribution patterns in relationship to geomorphic position in two tilled agricultural fields using the fallout Cesium-137 technique to measure soil redistribution. Cesium-137 and SOC concentrations in agricultural soils are significantly correlated in our study areas. Hillslope areas (eroding) have significantly less SOC than soils in toe slope areas (deposition). SOC decreased as gradient slope increases and soils on concave slopes had higher SOC than soils on convex slopes. These data suggest that soil redistribution patterns and topographic patterns may be used to help understand SOC dynamics on agricultural landscapes. Different productivity and oxidation rates of SOC of eroded versus deposited soils also contribute to SOC spatial patterns. However, the strong significant relationships between the patterns of soil redistribution and SOC concentrations in agricultural soils suggest that they are moving along similar physical pathways in these systems. Our study also indicates that geomorphic position is important for understanding soil and SOC movement and redistribution patterns within a field or watershed. Such information can help develop and implement management systems to increase SOC in agricultural ecosystems.

  11. Exploring the role of arbuscular mycorrhizal fungi in carbon sequestration in agricultural soil, Part III

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sequestering carbon in agricultural soils can help mitigate increases in atmospheric CO2. Work at Rodale Institute’s Farming Systems Trial indicates significant potential for carbon sequestration in organically farmed soils. A potential mechanism for this is C storage in the arbuscular mycorrhizal...

  12. Quantification of parameters controlling the carbon stocks in German agricultural soils

    NASA Astrophysics Data System (ADS)

    Vos, Cora; Don, Axel; Freibauer, Annette; Heidkamp, Arne; Prietz, Roland

    2016-04-01

    Within the framework of UNFCCC, Germany is obligated to report on its greenhouse gas emissions from soils. This also includes the emissions in the agricultural sector. Changes in soil carbon stocks are a major source of CO2 that need to be reported. Until now there are only regional inventories of the soil carbon stocks in the agricultural sector while for the forestry sector a repeated national inventory exists. In order to report on changes in soil carbon stocks in agricultural soils, a consistent, representative and quantitative dataset of agricultural soil properties, especially on carbon stocks and management data is necessary. In the course of the German Agricultural Soil Inventory 3109 agricultural sites are examined. Up to January 2016, 2450 sites were sampled. The sites are sampled in five depth increments and all samples are analyzed in the same laboratory. Of the sampled sites the laboratory analyses are completed for 1312 sites. The samples of all depth increments were analyzed for their texture, bulk density, pH, electric conductivity, stone and root content, organic and inorganic carbon content and nitrogen content. The data are coupled with management data covering the past ten years and with climate data. They are analyzed with multivariate statistical techniques (e.g. mixed effects models, additive models, random forest) to quantify the parameters that control the carbon stocks in German agricultural soils. First descriptive results show that the mean soil carbon stocks down to a depth of 100 cm are 126.1 t ha-1 (range 8.9-1158.9 t ha-1). The mean stocks only for croplands are 102.6 t ha-1 (range 8.9-1158.9 t ha-1), while for grasslands the mean stock is 184.1 t ha-1 (range 19.4-937.8 t ha-1). In total the soil scientists found a surprisingly high proportion of disturbed and unusual soil profiles, indicating intensive human modifications of agricultural soils through e.g. deep ploughing. The data set of the German Agricultural Soil Inventory is the

  13. Quantification of parameters controlling the carbon stocks in German agricultural soils

    NASA Astrophysics Data System (ADS)

    Vos, Cora; Don, Axel; Freibauer, Annette; Heidkamp, Arne; Prietz, Roland

    2016-04-01

    Within the framework of UNFCCC, Germany is obligated to report on its greenhouse gas emissions from soils. This also includes the emissions in the agricultural sector. Changes in soil carbon stocks are a major source of CO2 that need to be reported. Until now there are only regional inventories of the soil carbon stocks in the agricultural sector while for the forestry sector a repeated national inventory exists. In order to report on changes in soil carbon stocks in agricultural soils, a consistent, representative and quantitative dataset of agricultural soil properties, especially on carbon stocks and management data is necessary. In the course of the German Agricultural Soil Inventory 3109 agricultural sites are examined. Up to January 2016, 2450 sites were sampled. The sites are sampled in five depth increments and all samples are analyzed in the same laboratory. Of the sampled sites the laboratory analyses are completed for 1312 sites. The samples of all depth increments were analyzed for their texture, bulk density, pH, electric conductivity, stone and root content, organic and inorganic carbon content and nitrogen content. The data are coupled with management data covering the past ten years and with climate data. They are analyzed with multivariate statistical techniques (e.g. mixed effects models, additive models, random forest) to quantify the parameters that control the carbon stocks in German agricultural soils. First descriptive results show that the mean soil carbon stocks down to a depth of 100 cm are 126.1 t ha‑1 (range 8.9-1158.9 t ha‑1). The mean stocks only for croplands are 102.6 t ha‑1 (range 8.9-1158.9 t ha‑1), while for grasslands the mean stock is 184.1 t ha‑1 (range 19.4-937.8 t ha‑1). In total the soil scientists found a surprisingly high proportion of disturbed and unusual soil profiles, indicating intensive human modifications of agricultural soils through e.g. deep ploughing. The data set of the German Agricultural Soil

  14. Effects of agricultural intensification in the tropics on soil carbon losses and soil fertility

    NASA Astrophysics Data System (ADS)

    Guillaume, Thomas; Buttler, Alexandre; Kuzyakov, Yakov

    2016-04-01

    Tropical forest conversion to agricultural land leads to strong decrease of soil organic carbon (SOC). Nonetheless, the impacts of SOC losses on soil fertility remain unclear. We quantified SOC losses in forest, oil palm plantations, extensive rubber plantations and rubber monocultures on Sumatra Island (Indonesia). Furthermore, we assessed the response of biological (basal respiration, microbial biomass, acid phosphatase) and chemical fertility indicators (light fraction of OM, DOC, total N, available P) to SOC losses. We used a new approach based on (non-)linear regressions between SOC losses and the indicators, normalized to natural ecosystem values, to assess the sensitivity or resistance of fertility indicators to SOC losses. Carbon contents in the Ah horizon under oil palm and intensive rubber plantations were strongly reduced: up to 70% and 62%, respectively. The decrease was lower under extensive rubber (41%). The negative impact of land-use changes on all measured indicators increased in the following sequence: extensive rubber < rubber < oil palm. Basal respiration, microbial biomass and nutrients were comparatively resistant to SOC losses, whereas the light fraction of OM was lost faster than the SOC. The resistance of the microbial activity to SOC losses is an indication that microbial-mediated soil functions sustain SOC losses. However, responses of basal respiration and microbial biomass to SOC losses were non-linear. Below 2.7% C content, the relationship was reversed. The basal respiration decreased faster than the SOC, resulting in a stronger drop of microbial activity under oil palm compared to rubber, despite small difference in C content. We conclude that the new approach allows a quantitative assessment of the sensitivity and threshold of various soil functions to land-use changes and consequently, can be used to assess their resistance to agricultural intensification. Therefore, this method is appropriate to evaluate the environmental impacts

  15. A review on soil carbon accumulation due to the management change of major Brazilian agricultural activities.

    PubMed

    La Scala jr, N; De Figueiredo, E B; Panosso, A R

    2012-08-01

    Agricultural areas deal with enormous CO2 intake fluxes offering an opportunity for greenhouse effect mitigation. In this work we studied the potential of soil carbon sequestration due to the management conversion in major agricultural activities in Brazil. Data from several studies indicate that in soybean/maize, and related rotation systems, a significant soil carbon sequestration was observed over the year of conversion from conventional to no-till practices, with a mean rate of 0.41 Mg C ha(-1) year(-1). The same effect was observed in sugarcane fields, but with a much higher accumulation of carbon in soil stocks, when sugarcane fields are converted from burned to mechanised based harvest, where large amounts of sugarcane residues remain on the soil surface (1.8 Mg C ha(-1) year(-1)). The higher sequestration potential of sugarcane crops, when compared to the others, has a direct relation to the primary production of this crop. Nevertheless, much of this mitigation potential of soil carbon accumulation in sugarcane fields is lost once areas are reformed, or intensive tillage is applied. Pasture lands have shown soil carbon depletion once natural areas are converted to livestock use, while integration of those areas with agriculture use has shown an improvement in soil carbon stocks. Those works have shown that the main crop systems of Brazil have a huge mitigation potential, especially in soil carbon form, being an opportunity for future mitigation strategies.

  16. Dynamics of soil nitrogen and carbon accumulation for 61 years after agricultural abandonment

    SciTech Connect

    Knops, J.M.H.; Tilman, D.

    2000-01-01

    The authors used two independent methods to determine the dynamics of soil carbon and nitrogen following abandonment of agricultural fields on a Minnesota sand plain. First, they used a chronosequence of 19 fields abandoned from 1927 to 1982 to infer soil carbon and nitrogen dynamics. Second, they directly observed dynamics of carbon and nitrogen over a 12-yr period in 1900 permanent plots in these fields. These observed dynamics were used in a differential equation model to predict soil carbon and nitrogen dynamics. The two methods yielded similar results. Resampling the 1,900 plots showed that the rates of accumulation of nitrogen and carbon over 12 yr depended on ambient carbon and nitrogen levels in the soil, with rates of accumulation declining at higher carbon and nitrogen levels. A dynamic model fitted to the observed rates of change predicted logistic dynamics for nitrogen and carbon accumulation. On average, agricultural practices resulted in a 75% loss of soil nitrogen and an 89% loss of soil carbon at the time of abandonment. Recovery to 95% of the preagricultural levels is predicted the soil carbon, nitrogen, and carbon:nitrogen ratio patterns observed in the chronosequence of old fields, suggesting that the chronosequence may be indicative of actual changes in soil carbon and nitrogen. Their results suggest that the rate of carbon accumulation was controlled by the rate of nitrogen accumulation, which in turn depended on atmospheric nitrogen deposition and symbiotic nitrogen fixation by legumes. Their data support the hypothesis that these abandoned fields initially retain essentially all nitrogen and have a closed nitrogen cycle. Multiple regression suggests that vegetation composition had a significant influence on the rates of accumulation of both nitrogen and carbon; legumes increased these rates, and C{sub 3} grasses and forbs decreased them. C{sub 4} grasses increased the C:N ratio of the soil organic matter and thereby increased the rate of

  17. How can soil organic carbon stocks in agriculture be maintained or increased?

    NASA Astrophysics Data System (ADS)

    Don, Axel; Leifeld, Jens

    2015-04-01

    CO2 emissions from soils are 10 times higher than anthropogenic CO2 emissions from fossil burning with around 60 Pg C a-1. At the same time around 60 Pg of carbon is added to the soils as litter from roots and leaves. Thus, the balance between both fluxes is supposed to be zero for the global earth system in steady state without human perturbations. However, the global carbon flux has been altered by humans since thousands of years by extracting biomass carbon as food, feed and fiber with global estimate of 40% of net primary productivity (NPP). This fraction is low in forests but agricultural systems, in particular croplands, are systems with a high net exported carbon fraction. Soils are mainly input driven systems. Agricultural soils depend on input to compensate directly for i) respiration losses, ii) extraction of carbon (and nitrogen) and depletion (e.g. via manure) or indirectly via enhances NPP (e.g. via fertilization management). In a literature review we examined the role of biomass extraction and carbon input via roots, crop residues and amendments (manure, slurry etc.) to agricultural soil's carbon stocks. Recalcitrance of biomass carbon was found to be of minor importance for long-term carbon storage. Thus, also the impact of crop type on soil carbon dynamics seems mainly driven by the amount of crop residuals of different crop types. However, we found distinct differences in the efficiency of C input to refill depleted soil C stocks between above ground C input or below ground root litter C input, with root-C being more efficient due to slower turnover rates. We discuss the role of different measures to decrease soil carbon turnover (e.g. decreased tillage intensity) as compared to measures that increase C input (e.g. cover crops) in the light of global developments in agricultural management with ongoing specialization and segregation between catch crop production and dairy farms.

  18. Storing Carbon in Agricultural Soils to Help Head-Off Global Warming and to Combat Desertification

    SciTech Connect

    Rosenberg, Norman J.; Izaurralde, Roberto C.

    2001-12-31

    We know for sure that addition of organic matter to soil increases water-holding capacity, imparts fertility with the addition of nutrients, increases soil aggregation and improves tilth. Depeing on it's type, organic matter contains between 40 and 60% carbon. Using agricultural management practices to increase the amount of organic matter and carbon in soils can be an effective strategy to offset carbon dioxide emissions to the atmosphere as well as to improve the quality of the soil and slow or prevent desertification.

  19. Carbon amendment and soil depth affect the distribution and abundance of denitrifiers in agricultural soils.

    PubMed

    Barrett, M; Khalil, M I; Jahangir, M M R; Lee, C; Cardenas, L M; Collins, G; Richards, K G; O'Flaherty, V

    2016-04-01

    The nitrite reductase (nirS and nirK) and nitrous oxide reductase-encoding (nosZ) genes of denitrifying populations present in an agricultural grassland soil were quantified using real-time polymerase chain reaction (PCR) assays. Samples from three separate pedological depths at the chosen site were investigated: horizon A (0-10 cm), horizon B (45-55 cm), and horizon C (120-130 cm). The effect of carbon addition (treatment 1, control; treatment 2, glucose-C; treatment 3, dissolved organic carbon (DOC)) on denitrifier gene abundance and N2O and N2 fluxes was determined. In general, denitrifier abundance correlated well with flux measurements; nirS was positively correlated with N2O, and nosZ was positively correlated with N2 (P < 0.03). Denitrifier gene copy concentrations per gram of soil (GCC) varied in response to carbon type amendment (P < 0.01). Denitrifier GCCs were high (ca. 10(7)) and the bac:nirK, bac:nirS, bac:nir (T) , and bac:nosZ ratios were low (ca. 10(-1)/10) in horizon A in all three respective treatments. Glucose-C amendment favored partial denitrification, resulting in higher nir abundance and higher N2O fluxes compared to the control. DOC amendment, by contrast, resulted in relatively higher nosZ abundance and N2 emissions, thus favoring complete denitrification. We also noted soil depth directly affected bacterial, archaeal, and denitrifier abundance, possibly due to changes in soil carbon availability with depth.

  20. Litter contribution to soil organic carbon in the agriculture abandons processes

    NASA Astrophysics Data System (ADS)

    Novara, Agata; Francaviglia, Dario; La Mantia, tommaso; Gristina, Luciano; La Bella, Salvatore; Tuttolomondo, Teresa

    2015-04-01

    Mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in ecosystem functioning as it regulates the cycle of soil organic matter (SOM), CO2 emission into the atmosphere, carbon sequestration into the soil. In this study, it was investigated the contribution of litters of different stages of Mediterranean secondary succession on Carbon sequestration, analyzing the role of earthworms on translocation of SOM into soil profile. For this purpose δ13C difference between meadow C4-C soil and C3-C litter were used in a field experiment. Four undisturbed litters of different stages of succession were collected (45, 70, 100 and 120 since agriculture abandon) and placed on the top of isolated soil cores. The litter contribution to C stock was affected by plant species and increased with the age of the stage of secondary succession. The soil organic carbon after 1 year since litter position increased up to 40% in comparison to no litter treatment in soil with litter of 120 years since abandon. The new carbon derived from C3-litter was decomposed and transferred into soil profile thanks to earthworms and dissolved organic carbon leaching. After 1 years the carbon increase attributed to earthworm activity ranged from 6% to 13% in soil under litter in field abandoned since 120 and 45 years, respectively.

  1. Monitoring changes in soil carbon resulting from intensive production, a non-traditional agricultural methodology.

    SciTech Connect

    Dwyer, Brian P.

    2013-03-01

    New Mexico State University and a group of New Mexico farmers are evaluating an innovative agricultural technique they call Intensive Production (IP). In contrast to conventional agricultural practice, IP uses intercropping, green fallowing, application of soil amendments and soil microbial inocula to sequester carbon as plant biomass, resulting in improved soil quality. Sandia National Laboratories role was to identify a non-invasive, cost effective technology to monitor soil carbon changes. A technological review indicated that Laser Induced Breakdown Spectroscopy (LIBS) best met the farmers objectives. Sandia partnered with Los Alamos National Laboratory (LANL) to analyze farmers test plots using a portable LIBS developed at LANL. Real-time LIBS field sample analysis was conducted and grab samples were collected for laboratory comparison. The field and laboratory results correlated well implying the strong potential for LIBS as an economical field scale analytical tool for analysis of elements such as carbon, nitrogen, and phosphate.

  2. Effects of straw carbon input on carbon dynamics in agricultural soils: a meta-analysis.

    PubMed

    Liu, Chang; Lu, Meng; Cui, Jun; Li, Bo; Fang, Changming

    2014-05-01

    Straw return has been widely recommended as an environmentally friendly practice to manage carbon (C) sequestration in agricultural ecosystems. However, the overall trend and magnitude of changes in soil C in response to straw return remain uncertain. In this meta-analysis, we calculated the response ratios of soil organic C (SOC) concentrations, greenhouse gases (GHGs) emission, nutrient contents and other important soil properties to straw addition in 176 published field studies. Our results indicated that straw return significantly increased SOC concentration by 12.8 ± 0.4% on average, with a 27.4 ± 1.4% to 56.6 ± 1.8% increase in soil active C fraction. CO2 emission increased in both upland (27.8 ± 2.0%) and paddy systems (51.0 ± 2.0%), while CH4 emission increased by 110.7 ± 1.2% only in rice paddies. N2 O emission has declined by 15.2 ± 1.1% in paddy soils but increased by 8.3 ± 2.5% in upland soils. Responses of macro-aggregates and crop yield to straw return showed positively linear with increasing SOC concentration. Straw-C input rate and clay content significantly affected the response of SOC. A significant positive relationship was found between annual SOC sequestered and duration, suggesting that soil C saturation would occur after 12 years under straw return. Overall, straw return was an effective means to improve SOC accumulation, soil quality, and crop yield. Straw return-induced improvement of soil nutrient availability may favor crop growth, which can in turn increase ecosystem C input. Meanwhile, the analysis on net global warming potential (GWP) balance suggested that straw return increased C sink in upland soils but increased C source in paddy soils due to enhanced CH4 emission. Our meta-analysis suggested that future agro-ecosystem models and cropland management should differentiate the effects of straw return on ecosystem C budget in upland and paddy soils. PMID:24395454

  3. Black carbon contribution to stabilised SOM in soil under slash and burn agriculture

    NASA Astrophysics Data System (ADS)

    Rumpel, C.; Chaplot, V.; Valentin, C.

    2008-12-01

    Black carbon (BC) produced during slash and burn agriculture on tropical soils may enhance the soils organic matter content and hence their biological properties. However, once deposited on the soil surface, BC may be subject to erosion and/or microbial decomposition and thus not be preserved on site. Up to now, few studies have been carried out to assess the contribution of BC to the soils stable carbon pool on sites under slash and burn agriculture. The aim of the study was to assess the survival potential of BC in sloping tropical soils of clayey texture. The study was carried out in Northern Laos, where the soils are subjected to addition of black carbon produced by burning of agricultural crop residues. Our conceptual approach included the characterisation of (a) morphologically distinct BC forms and (b) chemical soil fractions. The samples were analysed for elemental content, chemical composition by 13C CPMAS NMR spectroscopy, carbon resistant to acid hydrolysis with HCl, carbon resistant to oxidation with acid dichromate solution and 14C activity. Our results indicated that BC produced by slash and burn agriculture was highly aromatic in nature. Its elemental composition as well as its susceptibility to be lost by chemical oxidation was dependent on its morphology. Acid hydrolysis did not lead to carbon loss from any BC form. We thus hypothesised that BC should be present in the hydrolysis resistant fraction isolated from soil. The charactersation of the chemical composition by 13C CPMAS NMR spectroscopy showed that the hydrolysis residue was composed of highly aromatic carbon. Considering the low lignin content of these soils and the good recovery of bulk soil aromatic carbon signal (80-100%) in the hydrolysis residue, we consider that this fraction may be suitable to assess BC contribution to clayey soils. We suggest that BC isolated as hydrolysis resistant C may represent up to 25% of the soils C as compared to 8% as isolated by acid dichromate oxidation

  4. The impact of agricultural soil erosion on the global carbon cycle

    USGS Publications Warehouse

    Van Oost, Kristof; Quine, T.A.; Govers, G.; De Gryze, S.; Six, J.; Harden, J.W.; Ritchie, J.C.; McCarty, G.W.; Heckrath, G.; Kosmas, C.; Giraldez, J.V.; Marques Da Silva, J.R.; Merckx, R.

    2007-01-01

    Agricultural soil erosion is thought to perturb the global carbon cycle, but estimates of its effect range from a source of 1 petagram per year -1 to a sink of the same magnitude. By using caesium-137 and carbon inventory measurements from a large-scale survey, we found consistent evidence for an erosion-induced sink of atmospheric carbon equivalent to approximately 26% of the carbon transported by erosion. Based on this relationship, we estimated a global carbon sink of 0.12 (range 0.06 to 0.27) petagrams of carbon per year-1 resulting from erosion in the world's agricultural landscapes. Our analysis directly challenges the view that agricultural erosion represents an important source or sink for atmospheric CO2.

  5. Litter contribution to soil organic carbon in the agriculture abandons processes

    NASA Astrophysics Data System (ADS)

    Novara, A.; Rühl, J.; La Mantia, T.; Gristina, L.; La Bella, S.; Tuttolomondo, T.

    2015-02-01

    Mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in ecosystem functioning as it regulates the cycle of soil organic matter (SOM), CO2 emission into the atmosphere, carbon sequestration into the soil. In this study, it was investigated the contribution of litters of different stages of Mediterranean secondary succession on Carbon sequestration, analyzing the role of earthworms on translocation of SOM into soil profile. For this purpose δ13C difference between meadow C4-Csoil and C3-Clitter were used in a field experiment. Four undisturbed litters of different stages of succession were collected (45, 70, 100 and 120 since agriculture abandon) and placed on the top of isolated soil cores. The litter contribution to C stock was affected by plant species and increased with the age of the stage of secondary succession. The soil organic carbon after 1 year since litter position increased up to 40% in comparison to no litter treatment in soil with litter of 120 years since abandon. The new carbon derived from C3-litter was decomposed and transferred into soil profile thanks to earthworms and dissolved organic carbon leaching. After 1 years the carbon increase attributed to earthworm activity ranged from 6 to 13% in soil under litter in field abandoned since 120 and 45 years, respectively.

  6. Stagnating crop yields: An overlooked risk for the carbon balance of agricultural soils?

    PubMed

    Wiesmeier, Martin; Hübner, Rico; Kögel-Knabner, Ingrid

    2015-12-01

    The carbon (C) balance of agricultural soils may be largely affected by climate change. Increasing temperatures are discussed to cause a loss of soil organic carbon (SOC) due to enhanced decomposition of soil organic matter, which has a high intrinsic temperature sensitivity. On the other hand, several modeling studies assumed that potential SOC losses would be compensated or even outperformed by an increased C input by crop residues into agricultural soils. This assumption was based on a predicted general increase of net primary productivity (NPP) as a result of the CO2 fertilization effect and prolonged growing seasons. However, it is questionable if the crop C input into agricultural soils can be derived from NPP predictions of vegetation models. The C input in European croplands is largely controlled by the agricultural management and was strongly related to the development of crop yields in the last decades. Thus, a glance at past yield development will probably be more instructive for future estimations of the C input than previous modeling approaches based on NPP predictions. An analysis of European yield statistics indicated that yields of wheat, barley and maize are stagnating in Central and Northern Europe since the 1990s. The stagnation of crop yields can probably be related to a fundamental change of the agricultural management and to climate change effects. It is assumed that the soil C input is concurrently stagnating which would necessarily lead to a decrease of agricultural SOC stocks in the long-term given a constant temperature increase. Remarkably, for almost all European countries that are faced with yield stagnation indications for agricultural SOC decreases were already found. Potentially adverse effects of yield stagnation on the C balance of croplands call for an interdisciplinary investigation of its causes and a comprehensive monitoring of SOC stocks in agricultural soils of Europe.

  7. Stagnating crop yields: An overlooked risk for the carbon balance of agricultural soils?

    PubMed

    Wiesmeier, Martin; Hübner, Rico; Kögel-Knabner, Ingrid

    2015-12-01

    The carbon (C) balance of agricultural soils may be largely affected by climate change. Increasing temperatures are discussed to cause a loss of soil organic carbon (SOC) due to enhanced decomposition of soil organic matter, which has a high intrinsic temperature sensitivity. On the other hand, several modeling studies assumed that potential SOC losses would be compensated or even outperformed by an increased C input by crop residues into agricultural soils. This assumption was based on a predicted general increase of net primary productivity (NPP) as a result of the CO2 fertilization effect and prolonged growing seasons. However, it is questionable if the crop C input into agricultural soils can be derived from NPP predictions of vegetation models. The C input in European croplands is largely controlled by the agricultural management and was strongly related to the development of crop yields in the last decades. Thus, a glance at past yield development will probably be more instructive for future estimations of the C input than previous modeling approaches based on NPP predictions. An analysis of European yield statistics indicated that yields of wheat, barley and maize are stagnating in Central and Northern Europe since the 1990s. The stagnation of crop yields can probably be related to a fundamental change of the agricultural management and to climate change effects. It is assumed that the soil C input is concurrently stagnating which would necessarily lead to a decrease of agricultural SOC stocks in the long-term given a constant temperature increase. Remarkably, for almost all European countries that are faced with yield stagnation indications for agricultural SOC decreases were already found. Potentially adverse effects of yield stagnation on the C balance of croplands call for an interdisciplinary investigation of its causes and a comprehensive monitoring of SOC stocks in agricultural soils of Europe. PMID:26235605

  8. The potential for carbon sequestration in Australian agricultural soils is technically and economically limited

    PubMed Central

    Lam, Shu Kee; Chen, Deli; Mosier, Arvin R.; Roush, Richard

    2013-01-01

    Concerns about increasing concentrations of greenhouse gases in the atmosphere, primarily carbon dioxide (CO2), have raised worldwide interest in the potential of agricultural soils to be carbon (C) sinks. In Australia, studies that have quantified the effects of improved management practices in croplands on soil C have generally been inconclusive and contradictory for different soil depths and durations of the management changes. We therefore quantitatively synthesised the results of Australian studies using meta-analytic techniques to assess the technical and economic feasibility of increasing the soil C stock by improved management practices. Our results indicate that the potential of these improved practices to store C is limited to the surface 0–10 cm of soil and diminishes with time. None of these widely adopted practices is currently financially attractive under Australia's new legislation known as the Carbon Farming Initiative. PMID:23846398

  9. Litter contribution to soil organic carbon in the processes of agriculture abandon

    NASA Astrophysics Data System (ADS)

    Novara, A.; Rühl, J.; La Mantia, T.; Gristina, L.; La Bella, S.; Tuttolomondo, T.

    2015-04-01

    The mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in the functioning of the ecosystem, as they regulate the cycle of soil organic matter (SOM) and CO2 emission into the atmosphere. In this study the contribution of litters of different stages of Mediterranean secondary succession on carbon sequestration was investigated, analyzing the role of earthworms in the translocation of SOM into the soil profile. For this purpose the δ13C difference between meadow C4-C soil and C3-C litter was used in a field experiment. Four undisturbed litters of different stages of succession (45, 70, 100 and 120 since agriculture abandon) were collected and placed on the top of isolated C4 soil cores. The litter contribution to C stock was affected by plant species and it increased with the age of the stage of secondary succession. One year after the litter position, the soil organic carbon increased up to 40% in comparison to soils not treated with litter after 120 years of abandon. The new carbon derived from C3 litter was decomposed and transferred into soil profile thanks to earthworms and the leaching of dissolved organic carbon. After 1 year the carbon increase attributed to earthworm activity was 6 and 13% in the soils under litter of fields abandoned for 120 and 45 years, respectively.

  10. Role of carbonates in soil organic matter stabilization in agricultural Mediterranean soils

    NASA Astrophysics Data System (ADS)

    Apesteguía, Marcos; Virto, Iñigo; Plante, Alain

    2016-04-01

    Carbonated soils are present in many semiarid areas, where lithogenic and secondary carbonates are important constituents of the soil mineral matrix. The presence of CaCO3 in calcareous soils has been described as an organic matter stabilization agent mainly due to chemical stabilization mechanisms. In two recent studies in the north of Spain the importance of CaCO3 on soil physical characteristics was highlighted, as they were observed to be acting as macroaggregates stabilization agents. A third study was carried out on the same experimental site, with the hypothesis that the observed differences in aggregation may favor organic matter stabilization in carbonate-containing soils. With that aim we studied the soil physical characteristics (water retention and porosity) and the bioavailability of soil organic matter (SOM) in the two contrasting soils in that site, one Typic Calcixerept (CALC) and one Calcic Haploxerept (DECALC). Bioavailability was evaluated trough the measurement of mineralization rates in a 30 days soil incubations. Intact and disaggregated samples were incubated to evaluate the effect of physical protection on SOM bioavailability in whole soil and macroaggregates 2-5 mm samples. Therefore, four fractions of each soil were studied: intact whole soil < 5 mm (I-WS), disaggregated whole soil (D-WS), intact macroaggregates 2-5 mm (I-Magg), and disaggregated macroaggregates (D-Magg). Soil organic carbon content was greater in CALC and had smaller mineralization rates during incubation, indicating a smaller organic matter bioavailability for microbial decomposition. However, the greater increment of mineralization observed in DECALC after disaggregation, together with the scarce differences observed in physical characteristics among both soils, indicate that physical protection was not responsible of greater SOM stability in CALC soil. New hypotheses are needed to explain the observed better protection of organic matter in carbonate-rich Mediterranean

  11. Soil carbon and soil respiration in conservation agriculture with vegetables in Siem Reap, Cambodia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A balance between food production and environmental protection is required to sustainably feed a growing population. The resource saving concept of conservation agriculture aims to achieve this balance through implementing simultaneously three conservation practices; no-till, continuous soil cover, ...

  12. Potential effect of No-till management on carbon in the agricultural soils of the former Soviet Union

    SciTech Connect

    Gaston, G.G.; Kolchugina, T.; Vinson, T.S.

    1993-01-01

    Agricultural soils act as both a source and a sink for atmospheric carbon. Since the onset of cultivation, the 211.5 million ha of agricultural soils in the former Soviet Union (FSU) have lost 10.2 Gt of carbon. No-till management represents a promising option to increase the amount of carbon sequestered in the agricultural soil of the FSU. No-till management reduces erosion and sequesters additional carbon in the soil by lowering the soil temperature and raising soil moisture. To determine the carbon sequestered under no-till management, a data base containing precultivation estimates of soil carbon for the seven major classes of soil found in the agricultural areas of the FSU was used to establish an equilibrium carbon content for each soil. Other published data provided a method to quantify the change in soil carbon brought about by converting to no-till management. Soils suitable for no-till management were analyzed and estimates of changes in carbon storage were made. No-till management is not suitable in areas where crop production is limited by cold, wet soils. (Copyright (c) 1993 Elsevier Science Publishers B.V.)

  13. Comparison of soil microbial respiration and carbon turnover under perennial and annual biofuel crops in two agricultural soils

    NASA Astrophysics Data System (ADS)

    Szymanski, L. M.; Marin-Spiotta, E.; Sanford, G. R.; Jackson, R. D.; Heckman, K. A.

    2015-12-01

    Bioenergy crops have the potential to provide a low carbon-intensive alternative to fossil fuels. More than a century of agricultural research has shown that conventional cropping systems can reduce soil organic matter (SOM) reservoirs, which cause long-term soil nutrient loss and C release to the atmosphere. In the face of climate change and other human disruptions to biogeochemical cycles, identifying biofuel crops that can maintain or enhance soil resources is desirable for the sustainable production of bioenergy. The objective of our study was to compare the effects of four biofuel crop treatments on SOM dynamics in two agricultural soils: Mollisols at Arlington Agricultural Research Station in Wisconsin and Alfisols at Kellogg Biological Station in Michigan, USA. We used fresh soils collected in 2013 and archived soils from 2008 to measure the effects of five years of crop management. Using a one-year long laboratory soil incubation coupled with a regression model and radiocarbon measurements, we separated soils into three SOM pools and their corresponding C turnover times. We found that the active pool, or biologically available C, was more sensitive to management and is an earlier indicator of changes to soil C dynamics than bulk soil C measurements. There was no effect of treatment on the active pool size at either site; however, the percent C in the active pool decreased, regardless of crop type, in surface soils with high clay content. At depth, the response of the slow pool differed between annual and perennial cropping systems. The distribution of C among SOM fractions varied between the two soil types, with greater C content associated with the active fraction in the coarser textured-soil and greater C content associated with the slow-cycling fraction in the soils with high clay content. These results suggest that the effects of bioenergy crops on soil resources will vary geographically, with implications for the carbon-cost of biocrop production.

  14. The fate of organic carbon in colluvial soils in a subtropical agricultural catchment (Arvorezinha, Brazil)

    NASA Astrophysics Data System (ADS)

    Van de Broek, Marijn; Van Oost, Kristof; Minella, Jean; Govers, Gerard

    2016-04-01

    One of the main reasons as to why soil erosion is considered to be a carbon sink for the atmosphere is that eroded carbon is often redeposited and buried in depositional environments. However, the quantification of the magnitude of this effect is still uncertain because the residence time of soil organic carbon in depositional environments is ill defined. The latter is especially true for tropical and subtropical areas as field data for these climatic zones are largely lacking. This is an important hiatus as ca. 40% of the total global arable land is located in the (sub-)tropics [1]. We collected samples from four depositional and one stable agricultural profile in a small agricultural catchment in Arvorezinha (Brazil) where deforestation started ca. 90 yrs ago. δ13C depth profiles allowed to identify the bottom of the original A-horizon: this is because δ13C values of the buried forest soils are significantly heavier than those of the colluvial deposits. The results show that soil organic carbon contents systematically decrease with depth below the actual plough layer. This is due to the fact that a significant fraction of the organic carbon that was originally deposited is removed by mineralization from these soils over decadal time scales. As the time of deforestation is known, age-depth curves could be established. Combining this information with SOC measurements allowed for a first estimate of carbon preservation rates and showed that after 70 years ca. 25% of the deposited organic carbon is released to the atmosphere: results were very consistent across profiles. In temperate environments, the time necessary for this fraction of the deposited carbon to be mineralized is somewhat longer, i.e. 100 years [2]. This suggests that soil organic carbon may be decomposed faster in sub-tropical environments in comparison to temperate environments. This is not unexpected, given the fact that average soil temperatures are higher and soils are, in this climate

  15. Interactive effects of agricultural management and topography on soil carbon sequestration

    NASA Astrophysics Data System (ADS)

    Ladoni, M.; Kravchenko, S.; Munoz, J.; Erickson, M.

    2012-12-01

    Proper agricultural management scenarios such as no-tillage, cover cropping, agroforestry, have demonstrated potential to increase the amount of carbon sequestered in soil and to mitigate atmospheric carbon levels. The knowledge about positive effects of cover cropping comes mostly from small uniform experimental plots, but whether these positive effects will exists in large scale fields with diverse topography and what would be the magnitude of these effects on a field scale remains to be seen. Our objective is to compare performance of different agricultural managements including those with cover crops in their influences on SOC across diverse topographical landscape in large agricultural fields. The three studied agricultural practices are Conventionally tilled and fertilized management without cover crops (T1), Low-input management with reduced chemical inputs (T3) and Organic (T4) management, the latter two have rye and red clover cover crops as part of their rotations. Within each field 1- 4 transects with three topographical positions of "depression", "slope" and "summit" were identified. The first soil sampling was done in spring 2010 and the second set of soil samples were collected from topographical positions during growing season of 2011. Samples were analyzed for total SOC and also particulate organic carbon (POC) content to show the changes in active pools of SOC. The results showed that topography has a significant influence in performance of cover crops. Agricultural managements with cover crops increased the POC in soil and the magnitude of this increase was different across space. Cover crops built the highest POC in depressions followed by summit and then slope. The conventional agricultural management increased POC in depression but decreased it on slopes. Low-input agricultural management when coupled with cover cropping has a potential to produce the highest increase in active pools of SOC across topographically diverse fields. The ratio of

  16. Modeling Soil Organic Carbon for Agricultural Land Use Under Various Management Practices

    NASA Astrophysics Data System (ADS)

    Kotamarthi, V. R.; Drewniak, B.; Song, J.; Prell, J.; Jacob, R. L.

    2009-12-01

    Bioenergy is generating tremendous interest as an alternative energy source that is both environmentally friendly and economically competitive. The amount of land designated for agriculture is expected to expand, including changes in the current distribution of crops, as demand for biofuels increases as a carbon neutral alternative fuel source. However, the influence of agriculture on the carbon cycle is complex, and varies depending on land use change and management practices. The purpose of this research is to integrate agriculture in the carbon-nitrogen based Community Land Model (CLM) to evaluate the above and below ground carbon storage for corn, soybean, and wheat crop lands. The new model, CLM-Crop simulates carbon allocation during four growth stages, a soybean nitrogen fixation scheme, fertilizer, and harvest practices. We present results from this model simulation, which includes the impact of a new dynamic roots module to simulate the changing root structure and depth with growing season based on the availability of water and nitrogen in the root zone and a retranslocation scheme to simulate redistribution of nitrogen from leaves, roots, and stems to grain during organ development for crop yields, leaf area index (LAI), carbon allocation, and changes in soil carbon budgets under various practices such as fertilizer and residue management. Simulated crop yields for corn, soybean and wheat are in general agreement with measurements. Initial model results indicate a loss of soil organic carbon over cultivated lands after removal of natural vegetation which continues in the following years. Soil carbon in crop lands is a strong function of the residue management and has the potential to impact crop yields significantly.

  17. Quantifying the erosion effect on current carbon budget of European agricultural soils at high spatial resolution.

    PubMed

    Lugato, Emanuele; Paustian, Keith; Panagos, Panos; Jones, Arwyn; Borrelli, Pasquale

    2016-05-01

    The idea of offsetting anthropogenic CO2 emissions by increasing global soil organic carbon (SOC), as recently proposed by French authorities ahead of COP21 in the 'four per mil' initiative, is notable. However, a high uncertainty still exits on land C balance components. In particular, the role of erosion in the global C cycle is not totally disentangled, leading to disagreement whether this process induces lands to be a source or sink of CO2. To investigate this issue, we coupled soil erosion into a biogeochemistry model, running at 1 km(2) resolution across the agricultural soils of the European Union (EU). Based on data-driven assumptions, the simulation took into account also soil deposition within grid cells and the potential C export to riverine systems, in a way to be conservative in a mass balance. We estimated that 143 of 187 Mha have C erosion rates <0.05 Mg C ha(-1) yr(-1), although some hot-spot areas showed eroded SOC >0.45 Mg C ha(-1) yr(-1). In comparison with a baseline without erosion, the model suggested an erosion-induced sink of atmospheric C consistent with previous empirical-based studies. Integrating all C fluxes for the EU agricultural soils, we estimated a net C loss or gain of -2.28 and +0.79 Tg yr(-1) of CO2 eq, respectively, depending on the value for the short-term enhancement of soil C mineralization due to soil disruption and displacement/transport with erosion. We concluded that erosion fluxes were in the same order of current carbon gains from improved management. Even if erosion could potentially induce a sink for atmospheric CO2, strong agricultural policies are needed to prevent or reduce soil erosion, in order to maintain soil health and productivity.

  18. An assessment of alternative agricultural management practice impacts on soil carbon in the corn belt

    SciTech Connect

    Barnwell, T.O. Jr.; Jackson, R.B.; Mulkey, L.A.

    1993-12-31

    This impact of alternative management practices on agricultural soil C is estimated by a soil C mass balance modeling study that incorporates policy considerations in the analysis. A literature review of soil C modeling and impacts of management practices has been completed. The models selected for use and/or modification to meet the needs of representing soil C cycles in agroecosystems and impacts of management practices are CENTURY and DNDC. These models share a common ability to examine the impacts of alternative management practices on soil organic C, and are readily accessible. An important aspect of this effort is the development of the modeling framework and methodology that define the agricultural production systems and scenarios (i.e., crop-soil-climate combinations) to be assessed in terms of national policy, the integration of the model needs with available databases, and the operational mechanics of evaluating C sequestration potential with the integrated model/database system. We are working closely with EPA`s Office of Policy and Program Evaluation to define a reasonable set of policy alternatives for this assessment focusing on policy that might be affected through a revised Farm Bill, such as incentives to selectively promote conservation tillage, crop rotations, and/or good stewardship of the conservation reserve. Policy alternatives are translated into basic data for use in soil C models through economic models. These data, including such elements as agricultural practices, fertilization rates, and production levels are used in the soil C models to produce net carbon changes on a per unit area basis. The unit-area emissions are combined with areal-extent data in a GIS to produce an estimate of total carbon and nitrogen changes and thus estimate greenhouse benefits.

  19. Soil organic carbon as a factor in passive microwave retrievals of soil water content over agricultural croplands

    NASA Astrophysics Data System (ADS)

    Manns, Hida R.; Berg, Aaron A.; Colliander, Andreas

    2015-09-01

    Remote sensing has the potential to deliver global soil water content (SWC) on vast scales with frequent revisit times for progress in the fields of climate, weather forecasting, agriculture and hydrology. Although surface roughness, vegetation and soil texture have been established as sources of variability in passive microwave interpretation, soil organic carbon (SOC) has not typically been considered as a factor that affects SWC estimation during field sampling campaigns. SOC was observed along with soil texture and bulk density during the Soil Moisture Active Passive Validation Experiment in 2012 (SMAPVEX12), the Soil Moisture Active Passive (SMAP) satellite algorithm development field sampling campaign held June 6 to July 19 in Southern Manitoba, Canada. Aerial measurements from the PALS (Passive Active L-band System) instrument were recorded over agricultural fields and forest areas from aircraft while SWC was measured simultaneously on the ground with resistance probes on 17 sampling dates. Additionally, fields were sampled for surface roughness, vegetation growth and water content, soil and vegetation temperature and soil physical characteristics. A soil core was collected on each field each sampling time to assess bulk density, soil particle size and SOC. SOC accounted for more variability in the anomalies between PALS and ground sampled SWC than sand, clay or bulk density, although all soil variables explained significant variability. With analysis by partial least squares multiple regression over 11 sampling dates and 39 fields where both ground and PALS data were well represented, only SOC contributed significantly to the regression of SWC beyond the variance all soil variables had in common. The significance of SOC in the relative SWC anomalies was highest in very wet and very dry conditions and in loam soil over all sampling dates, while bulk density was more significant in sand soils. This analysis suggests SOC is a simple variable that incorporates

  20. Increasing organic carbon stocks in Swedish agricultural soils due to unexpected socio-economic drivers

    NASA Astrophysics Data System (ADS)

    Poeplau, Christopher; Bolinder, Martin A.; Eriksson, Jan O.; Lundblad, Mattias; Kätterer, Thomas

    2015-04-01

    Management changes can induce significant alterations of soil organic carbon (SOC) stocks. Including trends in SOC within a certain land-use category can thus strongly influence the annual national inventory reports for greenhouse gas emissions. In 2013, the European Union has therefore decided that all member states shall report the evolvement of SOC within agricultural soils to increase the incentives to mitigate climate change by improving the management of those soils. Here, we present the country and county-wise SOC trends in Swedish agricultural mineral soils on the basis of three soil inventories conducted between 1988 and 2013. In the past two decades, the average topsoil (0-20 cm) SOC content of the whole country increased from 2.48% to 2.67% representing a relative change of 7.7% or 0.38% yr-1. This is in contrast to trends observed in neighboring countries such as Norway and Finland. We attributed this positive SOC trend to the increasing cultivation of leys throughout the country. Indeed, the below-ground carbon input of perennial grasses is up to fourfold as compared to cereals, which leads to a significant soil carbon sequestration potential under cropping systems with ley. The increase in ley proportion was significantly correlated to the increase in horse population in each county (R2=0.71), which has more than doubled in the past three decades. Due to subsidies introduced in the early 1990s, the area as long-term set-aside land (mostly old leys) also contributed to an increase in leys. This discloses the strong impact of rather local socio-economic trends on soil carbon storage, which also need to be considered in larger-scale model applications. This database is used in the continuous validation process of the Swedish national system for reporting changes in SOC stocks.

  1. Distribution of soil organic carbon in two small agricultural Mediterranean catchments.

    NASA Astrophysics Data System (ADS)

    Gomez, J. A.; Burguet, M.; Taguas, M. E.; Perez, R.; Ayuso, J. L.; Vanwallgehem, T.; Giraldez, J. V.; Vanderlinden, K.

    2012-04-01

    Soil organic carbon (SOC) is a key indicator of soil quality and a major factor for evaluating carbon sequestration schemes in forest and agricultural soils. However, at the farm or catchment scale SOC presents a large spatial variability which complicates the evaluation of soil quality (Gomez et al., 2009) and the certification of the potential for carbon sequestration. We hypothesize that the typical row crop configuration of olive orchards, with cover crops or bare soil in-between the rows, can explain a vast proportion of this variability. However, it is also expected that agricultural activities and topography-driven erosion processes at different scales (Van Oost et al., 2007) will contribute to SOC variability. Given the complexity of this problem and the important experimental effort required to resolve it, there are to our knowledge relatively few studies that have addressed this issue, especially in agricultural soils under Mediterranean conditions. This communications presents a preliminary evaluation of the top 1-m SOC content at two small, 8 and 6.7-ha, catchments in Southern Spain, covered by olive groves, that were intensively sampled in 2011. Spatial variability of SOC is analyzed across tree rows, areas in-between tree rows, and at different depths. The SOC distribution is evaluated against the topography of the catchment and the intensity of the water erosion processes analyzed by a simple model, such as SEDD, as used by Ferro and Porto (2000) and Taguas et al. (2011). The results of this communication will explore and discuss the differences between both catchments, and suggest guidelines for further exploring the sources of SOC variability, while providing guidelines to improve SOC estimation at the field scale for certification purposes.

  2. Carbon dioxide emissions from agricultural soils amended with livestock-derived organic materials

    NASA Astrophysics Data System (ADS)

    Pezzolla, D.; Said-Pullicino, D.; Gigliotti, G.

    2009-04-01

    Carbon dioxide gas xchange between terrestrial ecosystems and the atmosphere, as well as the carbon sink strength of various arable land ecosystems, is of primary interest for global change research. Measures for increasing soil C inputs include the preferential use of livestock-derived organic materials (e.g. animal manure and slurries, digestate from biogas production plants and compost). The application of such materials to agricultural soils returns essential nutrients for plant growth and organic matter to maintain long-term fertility. Whether or not such practices ultimately result in sustained C sequestration at the ecosystem level will depend on their mineralization rates. This work presents preliminary results from a laboratory incubation trial to evaluate carbon dioxide fluxes from two agricultural soils (a calcareous silt loam and a silty clay loam) amended with agricultural doses of (i) pig slurry (PSL), (ii) the digestate from the anaerobic fermentation of pig slurries (AAS) and (ii) a compost from the aerobic stabilisation of the digestate (LDC). These subsequent steps of slurry stabilisation resulted in a decrease in the content of labile organic matter which was reflected in a reduction in maximum carbon dioxide emission rates from amended soils. Measurements have shown that peak emissions from soils occur immediately after application of these organic materials (within 5 days) and decrease in the order PSL > AAS > LDC. Moreover, mean cumulative emissions over the first 40 days showed that a higher percentage (about 44%) of the C added with PSL was mineralised respect to C added with AAS (39%) and LDC (25%). Although it was hypothesised that apart from the quantity and stability of the added organic materials, even soil characteristics could influence C mineralisation rates, no significant differences were observed between emission fluxes for similarly treated soils. Mean cumulative emission fluxes after 40 days from treatment were of 114, 103 and

  3. 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.

  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. PMID:25822494

  5. 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

  6. Agricultural practices that store organic carbon in soils: is it only a matter of inputs ?

    NASA Astrophysics Data System (ADS)

    Chenu, Claire; Cardinael, Rémi; Autret, Bénédicte; Chevallier, Tiphaine; Girardin, Cyril; Mary, Bruno

    2016-04-01

    Increasing the world soils carbon stocks by a factor of 4 per mil annually would compensate the annual net increase of CO2 concentration in the atmosphere. This statement is the core of an initiative launched by the French government at the recent COP21, followed by many countries and international bodies, which attracts political attention to the storage potential of C in soils. Compared to forest and pasture soils, agricultural soils have a higher C storage potential, because they are often characterized by low C contents, and increasing their C content is associated with benefits in terms of soil properties and ecosystem services. Here we quantified, under temperate conditions, the additional C storage related to the implementation of two set of practices that are recognized to be in the framework of agroecology: conservation tillage on the one hand and agroforestry on the other hand. These studies were based on long-term experiments, a 16-years comparison on cropping systems on luvisols in the Paris area and a 18-year-old silvoarable agroforestry trial, on fluvisols in southern France, the main crops being cereals in both cases. C stocks were measured on an equivalent soil mass basis. Both systems allowed for a net storage of C in soils, which are, for the equivalent of the 0-30 cm tilled layer, of 0.55 ± 0.16 t ha- 1 yr- 1 for conservation agriculture (i.e. no tillage with permanent soil coverage with an associated plant, fescue or alfalfa) and of 0.25 ± 0.03 t ha-1 yr-1 for the agroforestry system. These results are in line with estimates proposed in a recent French national assessment concerning the potential of agricultural practices to reduce greenhouse gas emissions. Compared to recent literature, they further show that practices that increase C inputs to soil through additional biomass production would be more effective to store C in soil (tree rows, cover crops in conservation agriculture) than practices, such as no-tillage, that are assumed to reduce

  7. Agricultural practices that store organic carbon in soils: is it only a matter of inputs ?

    NASA Astrophysics Data System (ADS)

    Chenu, Claire; Cardinael, Rémi; Autret, Bénédicte; Chevallier, Tiphaine; Girardin, Cyril; Mary, Bruno

    2016-04-01

    Increasing the world soils carbon stocks by a factor of 4 per mil annually would compensate the annual net increase of CO2 concentration in the atmosphere. This statement is the core of an initiative launched by the French government at the recent COP21, followed by many countries and international bodies, which attracts political attention to the storage potential of C in soils. Compared to forest and pasture soils, agricultural soils have a higher C storage potential, because they are often characterized by low C contents, and increasing their C content is associated with benefits in terms of soil properties and ecosystem services. Here we quantified, under temperate conditions, the additional C storage related to the implementation of two set of practices that are recognized to be in the framework of agroecology: conservation tillage on the one hand and agroforestry on the other hand. These studies were based on long-term experiments, a 16-years comparison on cropping systems on luvisols in the Paris area and a 18-year-old silvoarable agroforestry trial, on fluvisols in southern France, the main crops being cereals in both cases. C stocks were measured on an equivalent soil mass basis. Both systems allowed for a net storage of C in soils, which are, for the equivalent of the 0-30 cm tilled layer, of 0.55 ± 0.16 t ha‑ 1 yr‑ 1 for conservation agriculture (i.e. no tillage with permanent soil coverage with an associated plant, fescue or alfalfa) and of 0.25 ± 0.03 t ha-1 yr-1 for the agroforestry system. These results are in line with estimates proposed in a recent French national assessment concerning the potential of agricultural practices to reduce greenhouse gas emissions. Compared to recent literature, they further show that practices that increase C inputs to soil through additional biomass production would be more effective to store C in soil (tree rows, cover crops in conservation agriculture) than practices, such as no-tillage, that are assumed to

  8. A new baseline of organic carbon stock in European agricultural soils using a modelling approach.

    PubMed

    Lugato, Emanuele; Panagos, Panos; Bampa, Francesca; Jones, Arwyn; Montanarella, Luca

    2014-01-01

    Proposed European policy in the agricultural sector will place higher emphasis on soil organic carbon (SOC), both as an indicator of soil quality and as a means to offset CO2 emissions through soil carbon (C) sequestration. Despite detailed national SOC data sets in several European Union (EU) Member States, a consistent C stock estimation at EU scale remains problematic. Data are often not directly comparable, different methods have been used to obtain values (e.g. sampling, laboratory analysis) and access may be restricted. Therefore, any evolution of EU policies on C accounting and sequestration may be constrained by a lack of an accurate SOC estimation and the availability of tools to carry out scenario analysis, especially for agricultural soils. In this context, a comprehensive model platform was established at a pan-European scale (EU + Serbia, Bosnia and Herzegovina, Croatia, Montenegro, Albania, Former Yugoslav Republic of Macedonia and Norway) using the agro-ecosystem SOC model CENTURY. Almost 164 000 combinations of soil-climate-land use were computed, including the main arable crops, orchards and pasture. The model was implemented with the main management practices (e.g. irrigation, mineral and organic fertilization, tillage) derived from official statistics. The model results were tested against inventories from the European Environment and Observation Network (EIONET) and approximately 20 000 soil samples from the 2009 LUCAS survey, a monitoring project aiming at producing the first coherent, comprehensive and harmonized top-soil data set of the EU based on harmonized sampling and analytical methods. The CENTURY model estimation of the current 0-30 cm SOC stock of agricultural soils was 17.63 Gt; the model uncertainty estimation was below 36% in half of the NUTS2 regions considered. The model predicted an overall increase of this pool according to different climate-emission scenarios up to 2100, with C loss in the south and east of the area

  9. Use of aerial photographs for assessment of soil organic carbon and delineation of agricultural management zones.

    NASA Astrophysics Data System (ADS)

    Bartholomeus, H.; Kooistra, L.

    2012-04-01

    For quantitative estimation of soil properties by means of remote sensing, often hyperspectral data are used. But these data are scarce and expensive, which prohibits wider implementation of the developed techniques in agricultural management. For precision agriculture, observations at a high spatial resolution are required. Colour aerial photographs at this scale are widely available, and can be acquired at no of very low costs. Therefore, we investigated whether publically available aerial photographs can be used to a) automatically delineate management zones and b) estimate levels of organic carbon spatially. We selected three study areas within the Netherlands that cover a large variance in soil type (peat, sand, and clay). For the fields of interest, RGB aerial photographs with a spatial resolution of 50 cm were extracted from a publically available data provider. Further pre-processing exists of geo-referencing only. Since the images originate from different sources and are potentially acquired under unknown illumination conditions, the exact radiometric properties of the data are unknown. Therefore, we used spectral indices to emphasize the differences in reflectance and normalize for differences in radiometry. To delineate management zones we used image segmentation techniques, using the derived indices as input. Comparison with management zone maps as used by the farmers shows that there is good correspondence. Regression analysis between a number of soil properties and the derived indices shows that organic carbon is the major explanatory variable for differences in index values within the fields. However, relations do not hold for large regions, indicating that local models will have to be used, which is a problem that is also still relevant for hyperspectral remote sensing data. With this research, we show that low-cost aerial photographs can be a valuable tool for quantitative analysis of organic carbon and automatic delineation of management zones

  10. Climate change effects on soil organic carbon changes in agricultural lands of Spain

    NASA Astrophysics Data System (ADS)

    Álvaro-Fuentes, J.; Easter, M.; Arrúe, J. L.; Cantero-Martínez, C.; Paustian, K.

    2012-04-01

    Climate is a key factor to explain changes in soil organic carbon (SOC) at regional scales. Experimental data have showed that spatial and temporal changes in soil temperature and moisture modify microbial activity and thus SOC decomposition. Furthermore, precipitation amount and distribution have a main impact on crop growth and residue production. According to predictions based on atmosphere-ocean general circulation models (AOGCM) for the next decades in the Mediterranean region, air temperature will significantly increase and precipitation decrease with a significant impact on SOC turnover. However, in agricultural systems, the study of the impacts of climate on SOC dynamics is a complex task since climate effects will be determined by both soil characteristics and management practices. The establishment of soil monitoring networks within a specific region is a recommended approach to study the interactive effects of climate, management and soil on SOC changes. However, in large areas, the establishment and maintenance of these networks can imply significant cost and time. A lower cost and time consuming approach can be the use of soil organic matter (SOM) models. The use of process based SOM models linked to spatial data through geographical information systems (GIS) permits to integrate the spatial variability of the parameters that control SOM dynamics. This approach can be appropriate for Spanish conditions where the complex orography results in a large range of local climates. Moreover, the large agricultural heterogeneity in terms of management systems could have a noteworthy impact on the effects of climate on SOC turnover in Spanish agroecosystems. Thus, in this study we used the Century model to analyse the impact of climate on SOC changes in a representative area of 40498 km2 located in northeast Spain. The spatial distribution of the different land use categories and their change over time was obtained from the European Corine database. Soil

  11. Carbon and Phosphorus in soil particulate fraction: effect of continuous agriculture, tillage and fertilization

    NASA Astrophysics Data System (ADS)

    Wyngaard, N.; Echeverrıa, H. E.; Vidaurreta, A.; Picone, L. I.; Divito, G. A.

    2012-04-01

    In Argentinean Pampas region, the practice of intensive agriculture has diminished total organic carbon (TOC) content in soil. This degradation process can impact over phosphorus (P) organic fractions associated to it, and therefore limit soil capacity to provide P through mineralization. Along this line, P content in soil particulate fraction (PF) has been proposed as an index to estimate this capacity. The aims of this work were to evaluate (1) the effect of continuous agriculture, tillage and P fertilization over TOC and P fractions content in soil and PF, and (2) the stability of P-PF as a mineralization index. To this end, a long term experiment initiated in 2001 in Balcarce, Argentina, under continuous agriculture, was analyzed. There, two tillage systems - conventional till (CT) and no till (NT) - and two fertilization treatments - nitrogen (N) and N + P (NP) - were evaluated. Phosphorus rate was 30 kg ha-1 year-1. In each plot, the following parameters were determined in 2002, 2005, 2008 and 2011: TOC, P Bray, total P (Pt), inorganic P (Pi), and organic P (Po) content in the whole soil and in the PF. Also, C supply by residues and P soil balance during the experiment were calculated, and the P sorption capacity was determined in samples from 2011. C supply was greater in CT (7% relative to NT) and in NP (14% relative to N). However, TOC in soil was not modified neither by tillage or fertilization. Even though, C in the PF decreased (3% annually) by the use of continuous agriculture. This reduction was positively associated to the one observed in other soil properties as Pt, Pi and Po in the PF. P fertilization lessened this reduction in Pt (18,9 mg kg-1 in N and 23,1 mg kg-1 in NP in 2011) and Pi (4,2 mg kg-1 in N and 6,2 mg kg-1 in NP in 2011), but not in Po. This indicates that, Po is affected by management practices and, contrary to Pt, is stable to fertilization. Therefore Po can be studied as a potential P mineralization index. The difference among P

  12. Landscape patterns and soil organic carbon stocks in agricultural bocage landscapes

    NASA Astrophysics Data System (ADS)

    Viaud, Valérie; Lacoste, Marine; Michot, Didier; Walter, Christian

    2014-05-01

    Soil organic carbon (SOC) has a crucial impact on global carbon storage at world scale. SOC spatial variability is controlled by the landscape patterns resulting from the continuous interactions between the physical environment and the society. Natural and anthropogenic processes occurring and interplaying at the landscape scale, such as soil redistribution in the lateral and vertical dimensions by tillage and water erosion processes or spatial differentiation of land-use and land-management practices, strongly affect SOC dynamics. Inventories of SOC stocks, reflecting their spatial distribution, are thus key elements to develop relevant management strategies to improving carbon sequestration and mitigating climate change and soil degradation. This study aims to quantify SOC stocks and their spatial distribution in a 1,000-ha agricultural bocage landscape with dairy production as dominant farming system (Zone Atelier Armorique, LTER Europe, NW France). The site is characterized by high heterogeneity on short distance due to a high diversity of soils with varying waterlogging, soil parent material, topography, land-use and hedgerow density. SOC content and stocks were measured up to 105-cm depth in 200 sampling locations selected using conditioned Latin hypercube sampling. Additive sampling was designed to specifically explore SOC distribution near to hedges: 112 points were sampled at fixed distance on 14 transects perpendicular from hedges. We illustrate the heterogeneity of spatial and vertical distribution of SOC stocks at landscape scale, and quantify SOC stocks in the various landscape components. Using multivariate statistics, we discuss the variability and co-variability of existing spatial organization of cropping systems, environmental factors, and SOM stocks, over landscape. Ultimately, our results may contribute to improving regional or national digital soil mapping approaches, by considering the distribution of SOC stocks within each modeling unit and

  13. Exogenous phosphorus inputs alter complexity of soil-dissolved organic carbon in agricultural riparian wetlands.

    PubMed

    Liu, Meng; Zhang, Zhijian; He, Qiang; Wang, Hang; Li, Xia; Schoer, Jonathan

    2014-01-01

    High-strengthened farmland fertilization leads to mass inputs of nutrients and elements to agricultural riparian wetlands. The dissolved organic carbon (DOC) of such wetland sediments is an important intermediate in global carbon (C) cycling due to its role in connecting soil C pools with atmospheric CO2. But the impact of phosphorus (P) on sediment DOC is still largely unknown, despite increasing investigations to emphasize P interception by riparian wetlands. Here, we simulated the temporal influences of exogenous P on sediment DOC of riparian wetlands by integrating gradient P loading at rates of 0%, 5%, 10%, 20%, 30%, and 60% relative to the initial total phosphorus content of the sediment with the purpose of illustrating the role of external P on the complexity of soil DOC in terms of its amount and composition. After incubating for nine months, a dramatic linear correlation between Olsen-P and fluorescent and ultraviolet spectral indices considered DOC skeleton was observed. Together with a more microbial-derived origin of DOC and a reduction of DOC aromaticity or humicity, the excitation-emission matrix had shown a blue shift reflecting a trend towards a simpler molecular structure of sediment DOC after P addition. Meanwhile, the content of soil DOC and its ratio with total organic carbon (TOC) were also increased by P loading, coupled with enhanced values of highly labile organic carbon and two C-related enzymes. While TOC and recalcitrant organic carbon decreased significantly. Such implications of DOC amounts and composition stimulated by external P loading may enhance its bioavailability, thereby inducing an accelerated effect on soil C cycling and a potential C loss in response to global climate change.

  14. Evaluation of a model framework to estimate soil and soil organic carbon redistribution by water and tillage using 137Cs in two U.S Midwest agricultural fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivated lands in the U.S. Midwest have been affected by soil erosion causing environmental and agricultural problems, including the redistribution of soil organic carbon (SOC) in the landscape. However, the importance of SOC redistribution on soil productivity and crop yield is still uncertain. I...

  15. Projected loss of soil organic carbon in temperate agricultural soils in the 21st century: effects of climate change and carbon input trends

    NASA Astrophysics Data System (ADS)

    Wiesmeier, Martin; Poeplau, Christopher; Sierra, Carlos A.; Maier, Harald; Frühauf, Cathleen; Hübner, Rico; Kühnel, Anna; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2016-09-01

    Climate change and stagnating crop yields may cause a decline of SOC stocks in agricultural soils leading to considerable CO2 emissions and reduced agricultural productivity. Regional model-based SOC projections are needed to evaluate these potential risks. In this study, we simulated the future SOC development in cropland and grassland soils of Bavaria in the 21st century. Soils from 51 study sites representing the most important soil classes of Central Europe were fractionated and derived SOC pools were used to initialize the RothC soil carbon model. For each site, long-term C inputs were determined using the C allocation method. Model runs were performed for three different C input scenarios as a realistic range of projected yield development. Our modelling approach revealed substantial SOC decreases of 11–16% under an expected mean temperature increase of 3.3 °C assuming unchanged C inputs. For the scenario of 20% reduced C inputs, agricultural SOC stocks are projected to decline by 19–24%. Remarkably, even the optimistic scenario of 20% increased C inputs led to SOC decreases of 3–8%. Projected SOC changes largely differed among investigated soil classes. Our results indicated that C inputs have to increase by 29% to maintain present SOC stocks in agricultural soils.

  16. Projected loss of soil organic carbon in temperate agricultural soils in the 21(st) century: effects of climate change and carbon input trends.

    PubMed

    Wiesmeier, Martin; Poeplau, Christopher; Sierra, Carlos A; Maier, Harald; Frühauf, Cathleen; Hübner, Rico; Kühnel, Anna; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2016-01-01

    Climate change and stagnating crop yields may cause a decline of SOC stocks in agricultural soils leading to considerable CO2 emissions and reduced agricultural productivity. Regional model-based SOC projections are needed to evaluate these potential risks. In this study, we simulated the future SOC development in cropland and grassland soils of Bavaria in the 21(st) century. Soils from 51 study sites representing the most important soil classes of Central Europe were fractionated and derived SOC pools were used to initialize the RothC soil carbon model. For each site, long-term C inputs were determined using the C allocation method. Model runs were performed for three different C input scenarios as a realistic range of projected yield development. Our modelling approach revealed substantial SOC decreases of 11-16% under an expected mean temperature increase of 3.3 °C assuming unchanged C inputs. For the scenario of 20% reduced C inputs, agricultural SOC stocks are projected to decline by 19-24%. Remarkably, even the optimistic scenario of 20% increased C inputs led to SOC decreases of 3-8%. Projected SOC changes largely differed among investigated soil classes. Our results indicated that C inputs have to increase by 29% to maintain present SOC stocks in agricultural soils. PMID:27585648

  17. Projected loss of soil organic carbon in temperate agricultural soils in the 21(st) century: effects of climate change and carbon input trends.

    PubMed

    Wiesmeier, Martin; Poeplau, Christopher; Sierra, Carlos A; Maier, Harald; Frühauf, Cathleen; Hübner, Rico; Kühnel, Anna; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2016-09-02

    Climate change and stagnating crop yields may cause a decline of SOC stocks in agricultural soils leading to considerable CO2 emissions and reduced agricultural productivity. Regional model-based SOC projections are needed to evaluate these potential risks. In this study, we simulated the future SOC development in cropland and grassland soils of Bavaria in the 21(st) century. Soils from 51 study sites representing the most important soil classes of Central Europe were fractionated and derived SOC pools were used to initialize the RothC soil carbon model. For each site, long-term C inputs were determined using the C allocation method. Model runs were performed for three different C input scenarios as a realistic range of projected yield development. Our modelling approach revealed substantial SOC decreases of 11-16% under an expected mean temperature increase of 3.3 °C assuming unchanged C inputs. For the scenario of 20% reduced C inputs, agricultural SOC stocks are projected to decline by 19-24%. Remarkably, even the optimistic scenario of 20% increased C inputs led to SOC decreases of 3-8%. Projected SOC changes largely differed among investigated soil classes. Our results indicated that C inputs have to increase by 29% to maintain present SOC stocks in agricultural soils.

  18. Projected loss of soil organic carbon in temperate agricultural soils in the 21st century: effects of climate change and carbon input trends

    PubMed Central

    Wiesmeier, Martin; Poeplau, Christopher; Sierra, Carlos A.; Maier, Harald; Frühauf, Cathleen; Hübner, Rico; Kühnel, Anna; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2016-01-01

    Climate change and stagnating crop yields may cause a decline of SOC stocks in agricultural soils leading to considerable CO2 emissions and reduced agricultural productivity. Regional model-based SOC projections are needed to evaluate these potential risks. In this study, we simulated the future SOC development in cropland and grassland soils of Bavaria in the 21st century. Soils from 51 study sites representing the most important soil classes of Central Europe were fractionated and derived SOC pools were used to initialize the RothC soil carbon model. For each site, long-term C inputs were determined using the C allocation method. Model runs were performed for three different C input scenarios as a realistic range of projected yield development. Our modelling approach revealed substantial SOC decreases of 11–16% under an expected mean temperature increase of 3.3 °C assuming unchanged C inputs. For the scenario of 20% reduced C inputs, agricultural SOC stocks are projected to decline by 19–24%. Remarkably, even the optimistic scenario of 20% increased C inputs led to SOC decreases of 3–8%. Projected SOC changes largely differed among investigated soil classes. Our results indicated that C inputs have to increase by 29% to maintain present SOC stocks in agricultural soils. PMID:27585648

  19. Organic amendments' dissolved organic carbon influences bioavailability of agricultural soil DOC

    NASA Astrophysics Data System (ADS)

    Straathof, Angela L.; Chincarini, Riccardo; Hoffland, Ellis; Comans, Rob N. J.

    2013-04-01

    Agricultural soils benefit from additions of organic amendments because they improve soil structure, are a source of plant nutrients, and increase concentrations of soil organic carbon (SOC). The latter fuels microbial processes important for plant growth, including nutrient mineralization and the suppression of plant diseases. However, these amendment additions range in quality and quantity of C and little is known about how their properties interact with native soil C and affect turnover. The dissolved pool of SOC (DOC) may be the most important C source for these processes as it is more biologically available and thus relatively easily turned over by the soil microbial biomass. Using a rapid-batch DOC fractionation procedure, we studied the composition of different organic amendments' DOC pools and measured how their additions change the quantity and turnover of soil DOC. Fractions isolated and quantified with this procedure include humic and fulvic acids, hydrophobic neutral and hydrophilic compounds. We hypothesized that these range from biologically recalcitrant to readily available, respectively. Amendments analysed included composts of different source materials and maturation stages collected from two different compost facilities in the Netherlands. Both total DOC concentrations and proportions of the aforementioned fractions ranged highly between composts. Composts cured for >10 days had a lower proportion of hydrophilic C compounds, suggesting that these are the most bioavailable and released as CO2 via microbial activity during maturation. To measure the effects of compost DOC on soil DOC, we extracted the former and added it to a sandy soil in an incubation experiment. The amendment increased soil total DOC, CO2 production from the soil, and the pools of humic and fulvic acids as a proportion of total DOC. Turnover of C from the incubated soil was measured by substrate-induced CO2 production (an indicator of microbial activity) from a 96-well

  20. Distribution of organic carbon in physical fractions of soils as affected by agricultural management

    SciTech Connect

    Sindhu, Jagadamma; Lal, Dr. Rattan

    2010-08-01

    Soil organic carbon (SOC) is distributed heterogeneously among different-sized primary particles and aggregates. Further, the SOC associated with different physical fractions respond differently to managements. Therefore, this study was conducted with the objective to quantify the SOC associated with all the three structural levels of SOC (particulate organic matter, soil separates and aggregate-size fractions) as influenced by long-term change in management. The study also aims at reevaluating the concept that the SOC sink capacity of individual size-fractions is limited. Long-term tillage and crop rotation effects on distribution of SOC among fractions were compared with soil from adjacent undisturbed area under native vegetation for the mixed, mesic, Typic Fragiudalf of Wooster, OH. Forty five years of no-till (NT) management resulted in more SOC accumulation in soil surface (0 7.5 cm) than in chisel tillage and plow tillage (PT) treatments. However, PT at this site resulted in a redistribution of SOC from surface to deeper soil layers. The soils under continuous corn accumulated significantly more SOC than those under corn soybean rotation at 7.5 45 cm depth. Although soil texture was dominated by the silt-sized particles, most of the SOC pool was associated with the clay fraction. Compared to PT, the NT treatment resulted in (i) significantly higher proportion of large macroaggregates (>2,000 m) and (ii) 1.5 2.8 times higher SOC concentrations in all aggregate-size classes. A comparative evaluation using radar graphs indicated that among the physical fractions, the SOC associated with sand and silt fractions quickly changed with a land use conversion from native vegetation to agricultural crops. A key finding of this study is the assessment of SOC sink capacity of individual fractions, which revealed that the clay fraction of agricultural soils continues to accumulate more SOC, albeit at a slower rate, with progressive increase in total SOC concentration

  1. Modeling biogeochemistry in agricultural soils

    SciTech Connect

    Li, C.; Frolking, S.; Harriss, R.

    1994-09-01

    An existing model of C and N dynamics in soils was supplemented with a plant growth submodel and cropping practice routines (fertilization, irrigation, tillage, crop rotation, and manure amendments) to study the biogeochemistry of soil carbon in arable lands. The new model was validated against field results for short-term (1-9 years) decomposition experiments, the seasonal pattern of soil CO{sub 2} respiration, and long-term (100 years) soil carbon storage dynamics. A series of sensitivity runs investigated the impact of varying agricultural practices on soil organic carbon (SOC) sequestration. The tests were simulated for corn (maize) plots over a range of soil and climate conditions typical of the United States. The largest carbon sequestration occurred with manure additions; the results were very sensitive to soil texture (more clay led to greater sequestration). Increased N fertilization generally enhanced carbon sequestration, but the results were sensitive to soil texture, initial soil carbon content, and annual precipitation. Reduced tillage also generally (but not always) increased SOC content, through the results were very sensitive to soil texture, initial SOC content, and annual precipitation. A series of long-term simulations investigated the SOC equilibrium for various agricultural practices, soil and climate conditions, and crop rotations. Equilibrium SOC content increased with decreasing temperatures, increasing clay content, enhanced N fertilization, manure amendments, and crops with higher residue yield. Time to equilibrium appears to be one hundred to several hundred years. In all cases, equilibration time was longer for increasing SOC content than for decreasing SOC content. Efforts to enhance carbon sequestration in agricultural soils would do well to focus on those specific areas and agricultural practices with the greatest potential for increasing soil carbon content. 64 refs., 13 figs., 5 tabs.

  2. Drivers of organic carbon stock of agricultural soils in eastern Australia

    NASA Astrophysics Data System (ADS)

    Rabbi, Sheikh M. F.; Tighe, Matthew; Delgado-Baquerizo, Manuel; Cowie, Annette; Robertson, Fiona; Dalal, Ram; Page, Kathryn; Crawford, Doug; Wilson, Brian; Schwenke, Graeme; Mcleod, Malem; Badgery, Warwick; Dang, Yash; Bell, Mike; Baldock, Jeff

    2015-04-01

    Assessing the factors that control carbon storage is the key to formulating conservation policies and sustainable soil management under changing environments. Here, we evaluate the major drivers of soil organic carbon storage in eastern Australia. To do this, we used a regional dataset including 1482 sites and targeting key land uses and soil management practices on major soils of New South Wales (NSW), Queensland (QLD) and Victoria (VIC). Structural equation modeling (SEM) and conditional inference tree (CTREE) analyses were performed to evaluate the relative importance of climate, topography, soil properties, land use and soil management practices on soil organic carbon stocks in 0-30 cm. The results showed that aridity, the most important factor controlling carbon storage, had a strong negative (r = -0.82, p<0.01), whereas clay content had a strong positive (r = 0.42, p<0.01) relationship with soil carbon stock. Only a small portion (<1%) of total variation in carbon stock could be explained by land use. The results of CTREE analysis showed that pastures, and pasture dominant crop-pasture rotations had positive influence on soil carbon stocks. The CTREE results also indicated that aridity regulates the amount of carbon present in the soil under different land uses. Using a novel multivariate technique the current work identified that aridity and clay content of soil are the main drivers of carbon storage at a regional scale over others factors such as land uses and soil management practices.

  3. Effect of crop residue incorporation on soil organic carbon (SOC) and greenhouse gas (GHG) emissions in European agricultural soils

    NASA Astrophysics Data System (ADS)

    Lehtinen, Taru; Schlatter, Norman; Baumgarten, Andreas; Bechini, Luca; Krüger, Janine; Grignani, Carlo; Zavattaro, Laura; Costamagna, Chiara; Spiegel, Heide

    2014-05-01

    Soil organic matter (SOM) improves soil physical (e.g. increased aggregate stability), chemical (e.g. cation exchange capacity) and biological (e.g. biodiversity, earthworms) properties. The sequestration of soil organic carbon (SOC) may mitigate climate change. However, as much as 25-75% of the initial SOC in world agricultural soils may have been lost due to intensive agriculture (Lal, 2013). The European Commission has described the decline of organic matter (OM) as one of the major threats to soils (COM(2006) 231). Incorporation of crop residues may be a sustainable and cost-efficient management practice to maintain the SOC levels and to increase soil fertility in European agricultural soils. Especially Mediterranean soils that have low initial SOC concentrations, and areas where stockless croplands predominate may be suitable for crop residue incorporation. In this study, we aim to quantify the effects of crop residue incorporation on SOC and GHG emissions (CO2 and N2O) in different environmental zones (ENZs, Metzger et al., 2005) in Europe. Response ratios for SOC and GHG emissions were calculated from pairwise comparisons between crop residue incorporation and removal. Specifically, we investigated whether ENZs, clay content and experiment duration influence the response ratios. In addition, we studied how response ratios of SOM and crop yields were correlated. A total of 718 response ratios (RR) were derived from a total of 39 publications, representing 50 experiments (46 field and 4 laboratory) and 15 countries. The SOC concentrations and stocks increased by approximately 10% following crop residue incorporation. In contrast, CO2 emissions were approximately six times and N2O emissions 12 times higher following crop residue incorporation. The effect of ENZ on the response ratios was not significant. For SOC concentration, the >35% clay content had significantly approximately 8% higher response ratios compared to 18-35% clay content. As the duration of the

  4. Mapping Soil Organic Carbon Resources Across Agricultural Land Uses in Highland Lesotho Using High Resolution Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Knight, J.; Adam, E.

    2015-12-01

    Mapping spatial patterns of soil organic carbon (SOC) using high resolution satellite imagery is especially important in inaccessible or upland areas that have limited field measurements, where land use and land cover (LULC) are changing rapidly, or where the land surface is sensitive to overgrazing and high rates of soil erosion and thus sediment, nutrient and carbon export. Here we outline the methods and results of mapping soil organic carbon in highland areas (~2400 m) of eastern Lesotho, southern Africa, across different land uses. Bedrock summit areas with very thin soils are dominated by xeric alpine grassland; terrace agriculture with strip fields and thicker soils is found within river valleys. Multispectral Worldview 2 imagery was used to map LULC across the region. An overall accuracy of 88% and kappa value of 0.83 were achieved using a support vector machine model. Soils were examined in the field from different LULC areas for properties such as soil depth, maturity and structure. In situ soils in the field were also evaluated using a portable analytical spectral device (ASD) in order to ground truth spectral signatures from Worldview. Soil samples were examined in the lab for chemical properties including organic carbon. Regression modeling was used in order to establish a relationship between soil characteristics and soil spectral reflectance. We were thus able to map SOC across this diverse landscape. Results show that there are notable differences in SOC between upland and agricultural areas which reflect both soil thickness and maturity, and land use practices such as manuring of fields by cattle. Soil erosion and thus carbon (nutrient) export is significant issue in this region, which this project will now be examining.

  5. Using 137Cs to study spatial patterns of soil erosion and soil organic carbon (SOC) in an agricultural catchment of the typical black soil region, Northeast China.

    PubMed

    Fang, Haiyan; Li, Qiuyan; Sun, Liying; Cai, Qiangguo

    2012-10-01

    Understanding the spatial pattern of soil organic carbon (SOC) is of great importance because of global environmental concerns. Soil erosion and its subsequent redistribution contribute significantly to the redistribution of SOC in agricultural ecosystems. This study investigated the relationships between (137)Cs and SOC over an agricultural landscape, and SOC redistribution was conducted for an agricultural catchment of the black soil region in Northeast China. The spatial patterns of (137)Cs and SOC were greatly affected by the established shelterbelts and the developed ephemeral gullies. (137)Cs were significantly correlated with SOC when (137)Cs were >2000 Bq m(-2), while no relation was observed between them when (137)Cs were <2000 Bq m(-2). Factors other than soil erosion such as vegetative productivity, mineralization of SOC, landscape position and management induced their spatial difference of (137)Cs and SOC. Using (137)Cs technique to directly study SOC dynamics must be cautious in the black soils. The net SOC loss rate across the entire catchment during 1954-2010 was 92.8 kg ha(-1) yr(-1), with around 42% of the eroded SOC being redeposited within the catchment. Such information can help guide shelterbelt establishment or other land management to reduce SOC loss in the agricultural ecosystems.

  6. Agricultural induced impacts on soil carbon cycling and sequestration in a seasonally saturated wetland

    NASA Astrophysics Data System (ADS)

    Maynard, J. J.; O'Geen, A. T.; Dahlgren, R. A.

    2011-06-01

    The fate of organic carbon (C) lost by erosion is not well understood in agricultural settings. Recent models suggest that wetlands and other small water bodies may serve as important long-term sinks of eroded C, receiving ~30 % of all eroded material in the US. To better understand the role of seasonally-saturated wetlands in sequestering eroded C, we examined the spatial and temporal dynamics of C and sediment accumulation in a 13-yr-old constructed wetland used to treat agricultural runoff. The fate of C sequestered within deposited sediment was modeled using point-sampling, remote sensing, and geostatistics. Using a spatially-explicit sampling design, annual net rates of sedimentation and above ground biomass were measured during two contrasting years (vegetated, 2004 vs. non-vegetated, 2005), followed by collection of sediment cores to the antecedent soil layer, representing 13 yr of sediment and C accumulation. We documented high annual variation in the relative contribution of endogenous and exogenous C sources, as well as absolute rates of sediment and C deposition. This annual variation, however, was muted in the long-term (13-yr) sediment record, which showed consistent vertical patterns of uniform C distribution (~14 g kg-1) and δ13C signatures in high depositional environments. This was in contrast to low depositional environments which had high levels of surface C enrichment (20-35 g kg-1) underlain by C depleted (5-10 g kg-1) sediments and an increasing δ13C signature with depth indicating increasing decomposition. These results highlight the importance of sedimentation in physically protecting soil organic carbon and its role in controlling the long-term C concentration of seasonally-saturated wetland soils. While significant enrichment of surface sediments with endogenous C occurred in newly deposited sediment (i.e., 125 kg m2 in 2004), fluctuating cycles of flooding and drying maintained the long-term C concentration at the same level as

  7. Soil carbon cycling and sequestration in a seasonally saturated wetland receiving agricultural runoff

    NASA Astrophysics Data System (ADS)

    Maynard, J. J.; Dahlgren, R. A.; O'Geen, A. T.

    2011-11-01

    The fate of organic carbon (C) lost by erosion is not well understood in agricultural settings. Recent models suggest that wetlands and other small water bodies may serve as important long-term sinks of eroded C, receiving ~30 % of all eroded material in the US. To better understand the role of seasonally-saturated wetlands in sequestering eroded C, we examined the spatial and temporal dynamics of C and sediment accumulation in a 13-year-old constructed wetland used to treat agricultural runoff. The fate of C sequestered within deposited sediment was modeled using point-sampling, remote sensing, and geostatistics. Using a spatially-explicit sampling design, annual net rates of sedimentation and above-ground biomass were measured during two contrasting years (vegetated (2004) vs. non-vegetated (2005)), followed by collection of sediment cores to the antecedent soil layer, representing 13 years of sediment and C accumulation. We documented high annual variation in the relative contribution of endogenous and exogenous C sources, as well as absolute rates of sediment and C deposition. This annual variation, however, was muted in the long-term (13 yr) sediment record, which showed consistent vertical patterns of uniform C distribution (~14 g kg-1) and δ13C signatures in high depositional environments. This was in contrast to low depositional environments which had high levels of surface C enrichment (20-35 g kg-1) underlain by C depleted (5-10 g kg-1) sediments and an increasing δ13C signature with depth indicating increased decomposition. These results highlight the importance of sedimentation in physically protecting soil organic carbon and its role in controlling the long-term C concentration of seasonally-saturated wetland soils. While significant enrichment of surface sediments with endogenous C occurred in newly deposited sediment (i.e., 125 kg m2 in 2004), fluctuating cycles of flooding and drying maintained the long-term C concentration at the same level as

  8. The impact of roots on soil organic carbon dynamics in annual and perennial agricultural systems

    NASA Astrophysics Data System (ADS)

    Beniston, J.; Dupont, T.; Glover, J.; Lal, R.

    2012-12-01

    Identifying and developing agricultural systems capable of transferring large quantities of carbon (C) to the soil and sustaining ecosystem processes and services is a priority for ecological researchers and land managers. Temperate grasslands have extensive root systems and transfer large quantities of C to the soil organic C (SOC) pool, which has lead to widespread interest in utilizing perennial grasses as both bioenergy crops and as a model for perennial grains. This study examined five sites in north central Kansas (U.S.A.) that contain the unique land use pairing of tall grass prairie meadows (PM) that have been harvested annually for hay for the past 75 years and annual grain (wheat) production fields (AG) that have been cultivated for a similar length of time, all on deep alluvial soils. Specific research objectives included: 1) To quantify below-ground biomass pools and root C contributions in the two systems; 2) To analyze and compare SOC pools and SOC concentration in primary particle size fractions in the two systems; 3) To utilize natural abundance δ13C signatures to determine the source and turnover of SOC in the soils of the AG sites; and 4) To elucidate the relationship of roots to both SOC pools and nematode food webs. Soil core samples were collected to a depth of 1 m in May and June 2008. Soil samples were analyzed for SOC, microbial biomass C (MBC), nematodes, and a particle size fractionation of SOC in coarse (>250 μm), particulate organic matter (POM) (53-250 μm), silt (2-53 μm), and clay (<2 μm) sized fractions. Root biomass, root length and root C were also analyzed to a depth of 1 m. Natural abundance δ13C values were obtained for all C parameters. Soils under PM had 4 times as much root C as AG soils to 1 m depth in mid May (PM 2.8 Mg ha-1 and AG 0.7 Mg ha-1) and 7 times as much root C to 1 m depth in late June (PM 3.5 Mg ha-1 and AG 0.5 Mg ha-1). The MBC pools were significantly larger in grassland soils to a depth of 60 cm in May

  9. Increase in soil organic carbon by agricultural intensification in northern China

    NASA Astrophysics Data System (ADS)

    Liao, Y.; Wu, W. L.; Meng, F. Q.; Smith, P.; Lal, R.

    2015-03-01

    Agricultural intensification has contributed greatly to the sustained food supply of China's population of 1.3 billion over the 30-year period from 1982 to 2011. Intensification has several and widely recognized negative environmental impacts including depletion of water resources, pollution of water bodies, greenhouse gas emissions and soil acidification. However, there have been few studies over this period on the impacts of intensification on soil organic carbon (SOC) at the regional level. The present study was conducted in Huantai County, a typical intensive farming region in northern China, to analyze the temporal dynamics of SOC influenced by climate and farming practices. The results indicate that from 1982 to 2011, SOC content and density in the 0-20 cm layer of the cropland increased from 7.8 ± 1.6 to 11.0 ± 2.3 g kg-1 (41%) and from 21.4 ± 4.3 to 33.0 ± 7.0 Mg ha-1 (54%), respectively. The SOC stock (0-20 cm) of the farmland for the entire county increased from 0.75 to 1.2 Tg (59%). Correlation analysis revealed that incorporation of crop residues significantly increased SOC, while an increase in the mean annual temperature decreased the SOC level. Therefore, agricultural intensification has increased crop productivity and contributed to SOC sequestration in northern China. In the near future, more appropriate technologies and practices must be developed and implemented for a maintenance or enhancement of SOC in this region and elsewhere in northern China, which also reduce non-CO2 greenhouse gas emissions, since the climate benefit from the additional SOC storage is estimated to be smaller than the negative climate impacts of N2O from N fertilizer additions.

  10. Increase in soil organic carbon by agricultural intensification in northern China

    NASA Astrophysics Data System (ADS)

    Liao, Y.; Wu, W. L.; Meng, F. Q.; Smith, P.; Lal, R.

    2014-11-01

    Agricultural intensification has contributed greatly to the sustained food supply of China's 1.3 billion population over the 30 year period during 1982-2011. Intensification has several and widely recognized negative environmental impacts including depletion of water resources, pollution of water bodies, greenhouse gas emissions and soil acidification. However, there have been few studies over this period on the impacts of intensification on soil organic carbon (SOC) at the regional level. The present study was conducted in Huantai county, a typical intensive farming region in Northern China, to analyze the temporal dynamics of SOC influenced by climate and farming practices. The results indicate that from 1982 to 2011, SOC content and stock in the 0-20 cm layer of the cropland increased from 7.8 ± 1.6 to 11.0 ± 2.3 g kg-1 (41%) and 21 ± 4.3 to 33.0 ± 7.0 Mg ha-1 (54%), respectively. The SOC stock (0-20 cm) of the farmland for the entire county increased from 0.75 to 1.2 Tg (59%). Correlation analysis revealed that incorporation of crop residues significantly increased SOC, while increase in the mean annual temperature decreased the SOC level. Therefore, agricultural intensification has increased crop productivity and contributed to SOC sequestration in Northern China. In the near future, more appropriate technologies and practices must be developed and implemented for a maintenance or enhancement of SOC in this region and elsewhere in Northern China, that also reduce non-CO2 greenhouse gas emissions, since the climate benefit from the additional SOC storage is estimated to be smaller than the negative climate impacts of N2O from N fertilizer additions.

  11. Soil respiration characteristics in different land uses and response of soil organic carbon to biochar addition in high-latitude agricultural area.

    PubMed

    Ouyang, Wei; Geng, Xiaojun; Huang, Wejia; Hao, Fanghua; Zhao, Jinbo

    2016-02-01

    The farmland tillage practices changed the soil chemical properties, which also impacted the soil respiration (R s ) process and the soil carbon conservation. Originally, the farmland in northeast China had high soil carbon content, which was decreased in the recent decades due to the tillage practices. To better understand the R s dynamics in different land use types and its relationship with soil carbon loss, soil samples at two layers (0-15 and 15-30 cm) were analyzed for organic carbon (OC), total nitrogen (TN), total phosphorus (TP), total carbon (TC), available nitrogen (AN), available phosphorus (AP), soil particle size distribution, as well as the R s rate. The R s rate of the paddy land was 0.22 (at 0-15 cm) and 3.01 (at 15-30 cm) times of the upland. The average concentrations of OC and clay content in cultivated areas were much lower than in non-cultivated areas. The partial least squares analysis suggested that the TC and TN were significantly related to the R s process in cultivated soils. The upland soil was further used to test soil CO2 emission response at different biochar addition levels during 70-days incubation. The measurement in the limited incubation period demonstrated that the addition of biochar improved the soil C content because it had high concentration of pyrogenic C, which was resistant to mineralization. The analysis showed that biochar addition can promote soil OC by mitigating carbon dioxide (CO2) emission. The biochar addition achieved the best performance for the soil carbon conservation in high-latitude agricultural area due to the originally high carbon content.

  12. Soil respiration characteristics in different land uses and response of soil organic carbon to biochar addition in high-latitude agricultural area.

    PubMed

    Ouyang, Wei; Geng, Xiaojun; Huang, Wejia; Hao, Fanghua; Zhao, Jinbo

    2016-02-01

    The farmland tillage practices changed the soil chemical properties, which also impacted the soil respiration (R s ) process and the soil carbon conservation. Originally, the farmland in northeast China had high soil carbon content, which was decreased in the recent decades due to the tillage practices. To better understand the R s dynamics in different land use types and its relationship with soil carbon loss, soil samples at two layers (0-15 and 15-30 cm) were analyzed for organic carbon (OC), total nitrogen (TN), total phosphorus (TP), total carbon (TC), available nitrogen (AN), available phosphorus (AP), soil particle size distribution, as well as the R s rate. The R s rate of the paddy land was 0.22 (at 0-15 cm) and 3.01 (at 15-30 cm) times of the upland. The average concentrations of OC and clay content in cultivated areas were much lower than in non-cultivated areas. The partial least squares analysis suggested that the TC and TN were significantly related to the R s process in cultivated soils. The upland soil was further used to test soil CO2 emission response at different biochar addition levels during 70-days incubation. The measurement in the limited incubation period demonstrated that the addition of biochar improved the soil C content because it had high concentration of pyrogenic C, which was resistant to mineralization. The analysis showed that biochar addition can promote soil OC by mitigating carbon dioxide (CO2) emission. The biochar addition achieved the best performance for the soil carbon conservation in high-latitude agricultural area due to the originally high carbon content. PMID:26408119

  13. Predicting Agricultural Management Influence on Long-Term Soil Organic Carbon Dynamics: Implications for Biofuel Production

    SciTech Connect

    Gollany, H. T.; Rickman, R. W.; Albrecht, S. L.; Liang, Y.; Kang, Shujiang; Machado, S.

    2011-01-01

    Long-term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model and (ii) to predict the potential of no-tillage (NT) management to maintain SOC stocks while removing crop residue. Classical LTEs at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) were selected for their documented history of management practice and periodic soil organic matter (SOM) measurements. Management practices ranged from monoculture to 2- or 3-yr crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned, or harvested. Measured and CQESTR predicted SOC stocks under diverse agronomic practices, mean annual temperature (2.1 19 C), precipitation (402 973 mm), and SOC (5.89 33.58 g SOC kg 1) at the LTE sites were significantly related (r 2 = 0.94, n = 186, P < 0.0001) with a slope not significantly different than 1. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing SOC stocks were influenced by initial SOC stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under NT are options to mitigate loss of crop residue C, as using fertilizer alone is insufficient to overcome residue removal impact on SOC stocks

  14. Modelling the impact of agricultural management on soil carbon stocks at the regional scale: the role of lateral fluxes.

    PubMed

    Nadeu, Elisabet; Gobin, Anne; Fiener, Peter; van Wesemael, Bas; van Oost, Kristof

    2015-08-01

    Agricultural management has received increased attention over the last decades due to its central role in carbon (C) sequestration and greenhouse gas mitigation. Yet, regardless of the large body of literature on the effects of soil erosion by tillage and water on soil organic carbon (SOC) stocks in agricultural landscapes, the significance of soil redistribution for the overall C budget and the C sequestration potential of land management options remains poorly quantified. In this study, we explore the role of lateral SOC fluxes in regional scale modelling of SOC stocks under three different agricultural management practices in central Belgium: conventional tillage (CT), reduced tillage (RT) and reduced tillage with additional carbon input (RT+i). We assessed each management scenario twice: using a conventional approach that did not account for lateral fluxes and an alternative approach that included soil erosion-induced lateral SOC fluxes. The results show that accounting for lateral fluxes increased C sequestration rates by 2.7, 2.5 and 1.5 g C m(-2)  yr(-1) for CT, RT and RT+i, respectively, relative to the conventional approach. Soil redistribution also led to a reduction of SOC concentration in the plough layer and increased the spatial variability of SOC stocks, suggesting that C sequestration studies relying on changes in the plough layer may underestimate the soil's C sequestration potential due to the effects of soil erosion. Additionally, lateral C export from cropland was in the same of order of magnitude as C sequestration; hence, the fate of C exported from cropland into other land uses is crucial to determine the ultimate impact of management and erosion on the landscape C balance. Consequently, soil management strategies targeting C sequestration will be most effective when accompanied by measures that reduce soil erosion given that erosion loss can balance potential C uptake, particularly in sloping areas.

  15. Modelling the impact of agricultural management on soil carbon stocks at the regional scale: the role of lateral fluxes.

    PubMed

    Nadeu, Elisabet; Gobin, Anne; Fiener, Peter; van Wesemael, Bas; van Oost, Kristof

    2015-08-01

    Agricultural management has received increased attention over the last decades due to its central role in carbon (C) sequestration and greenhouse gas mitigation. Yet, regardless of the large body of literature on the effects of soil erosion by tillage and water on soil organic carbon (SOC) stocks in agricultural landscapes, the significance of soil redistribution for the overall C budget and the C sequestration potential of land management options remains poorly quantified. In this study, we explore the role of lateral SOC fluxes in regional scale modelling of SOC stocks under three different agricultural management practices in central Belgium: conventional tillage (CT), reduced tillage (RT) and reduced tillage with additional carbon input (RT+i). We assessed each management scenario twice: using a conventional approach that did not account for lateral fluxes and an alternative approach that included soil erosion-induced lateral SOC fluxes. The results show that accounting for lateral fluxes increased C sequestration rates by 2.7, 2.5 and 1.5 g C m(-2)  yr(-1) for CT, RT and RT+i, respectively, relative to the conventional approach. Soil redistribution also led to a reduction of SOC concentration in the plough layer and increased the spatial variability of SOC stocks, suggesting that C sequestration studies relying on changes in the plough layer may underestimate the soil's C sequestration potential due to the effects of soil erosion. Additionally, lateral C export from cropland was in the same of order of magnitude as C sequestration; hence, the fate of C exported from cropland into other land uses is crucial to determine the ultimate impact of management and erosion on the landscape C balance. Consequently, soil management strategies targeting C sequestration will be most effective when accompanied by measures that reduce soil erosion given that erosion loss can balance potential C uptake, particularly in sloping areas. PMID:25663657

  16. [Response of Soil Respiration and Organic Carbon to Returning of Different Agricultural Straws and Its Mechanism].

    PubMed

    Cao, Zhan-bo; Wang, Lei; Li, Fan; Fu, Xiao-hua; Le, Yi-quan; Wu, Ji-hua; Lu, Bing; Xu, Dian-sheng

    2016-05-15

    Soybean, maize and rice straws were selected as raw materials to study the response of the soil respiration (SR) and soil organic carbon (SOC) to returning of different straws in the Chongming Dongtan area. The results showed that all of SR, SOC and the plant biomass of the lands with returning of different straws were higher than those of the controls. The soil with soybean straw returning possessed the lowest SR and highest SOC among the three kinds of straws, meaning its higher soil organic carbon sequestration capability than corn and maize straws returning. Straw returning significantly enhanced soil dehydrogenase, β-glycosidase activities and microbial biomass, and soil dehydrogenase activity was significantly correlated with soil respiration. The dehydrogenase activity of the soil with soybean straw returning was the lowest, thus, the lowest SR and highest SOC. Soybean straw had the highest cellulose and lignin contents and the lowest N content among the three kinds of straws, resulting in its lowest biodegradability. Therefore, when soybean straw was returned to soil, it was difficult to degrade completely by soil microorganisms, thus the lowest soil microbial activity, eventually leading to the lowest SR and highest SOC.

  17. [Response of Soil Respiration and Organic Carbon to Returning of Different Agricultural Straws and Its Mechanism].

    PubMed

    Cao, Zhan-bo; Wang, Lei; Li, Fan; Fu, Xiao-hua; Le, Yi-quan; Wu, Ji-hua; Lu, Bing; Xu, Dian-sheng

    2016-05-15

    Soybean, maize and rice straws were selected as raw materials to study the response of the soil respiration (SR) and soil organic carbon (SOC) to returning of different straws in the Chongming Dongtan area. The results showed that all of SR, SOC and the plant biomass of the lands with returning of different straws were higher than those of the controls. The soil with soybean straw returning possessed the lowest SR and highest SOC among the three kinds of straws, meaning its higher soil organic carbon sequestration capability than corn and maize straws returning. Straw returning significantly enhanced soil dehydrogenase, β-glycosidase activities and microbial biomass, and soil dehydrogenase activity was significantly correlated with soil respiration. The dehydrogenase activity of the soil with soybean straw returning was the lowest, thus, the lowest SR and highest SOC. Soybean straw had the highest cellulose and lignin contents and the lowest N content among the three kinds of straws, resulting in its lowest biodegradability. Therefore, when soybean straw was returned to soil, it was difficult to degrade completely by soil microorganisms, thus the lowest soil microbial activity, eventually leading to the lowest SR and highest SOC. PMID:27506047

  18. Projected changes of soil organic carbon in agricultural soils of southeast Germany in the 21th century under different carbon input scenarios

    NASA Astrophysics Data System (ADS)

    Wiesmeier, Martin; Poeplau, Christopher; Sierra, Carlos; Maier, Harald; Hübner, Rico; Kühnel, Anna; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2016-04-01

    As climate change may have a distinct effect on soil organic carbon (SOC) stocks, projections of the future SOC development on larger spatial scales on the basis of soil carbon models are needed. In this study we simulated the SOC development in cropland and grassland soils of Bavaria (southeast Germany) between 2000 and 2095 using the RothC model. At 51 sampling locations detailed model input data as C pools derived by soil fractionation, C input, clay content and climate variables were determined to run the model. Projections for each sampling location were performed on the basis of an average climate scenario (A1B) and three C input scenarios as a realistic range of possible crop yield developments: stagnation of the C input (1) increase by 20% (2) and decrease by 20% (3). The results showed a general decline of SOC stocks of 12% during the 21th century under C input scenario 1 and a decrease of 21% under scenario 3. Remarkably, even the optimistic scenario 2 resulted in a noticeable decline of SOC stocks by 5%. Our study indicated that C inputs in agricultural soils of Bavaria have to increase by 30% until 2095 (given the A1B climate scenario) in order to maintain present SOC stocks. However, projected SOC changes largely depended on the soil unit and regional site characteristics. The modeling approach provides the basis for a further evaluation of changes of the land use management and enables a site-specific delineation of measures for a sustainable supply of soil organic matter under climate change.

  19. The fate of soil organic carbon upon erosion, transport and deposition in agricultural landscapes - A review of different concepts

    NASA Astrophysics Data System (ADS)

    Kirkels, F. M. S. A.; Cammeraat, L. H.; Kuhn, N. J.

    2014-12-01

    Erosion and deposition redistribute large quantities of sediment and soil organic carbon (SOC) in agricultural landscapes. In the perspective of global carbon cycling, the coupling between erosion processes and the fate of SOC is of particular interest. However, different concepts have been proposed to assess the impact of erosion-induced lateral and vertical carbon fluxes. On landscape scale, this resulted in contrasting conclusions if agricultural soils represent either a carbon sink or source. The large global area of arable soil and generally high erosion rates, make these insights important. In this review, we aim to give an overview of the different conceptual relations described governing C dynamics at sites of erosion, along the transport pathway and at depositional sites and the current state of knowledge on the fate of SOC upon erosion, transport and deposition in agricultural landscapes. The impact of erosion on SOC dynamics differs for sites of erosion, deposition and during transport, with further influences by agricultural practices (e.g. tillage and fertilisation). Controlling processes are the detachment of sediment and SOC, net primary production resulting in dynamic replacement and changes in mineralisation upon transport and deposition due to aggregate breakdown and deep burial, respectively. However, the exact magnitude and dominance of these processes are debated, resulting in a controversy whether arable land functions as a sink or source for atmospheric CO2. Global estimations range between a net sink strength of 0.06-1 versus a source of 0.27-1.14 Gt C yr- 1 for agricultural soils. An eco-geomorphologic approach, which encompasses physical- and biological-driven factors (e.g. spatio-temporal variation in biological, geomorphological and biological processes, environmental conditions, mineralisation, and net primary production) is of importance to balance the carbon budget and ascertain sink or source formation at landscape scale. High spatio

  20. Positive trends in organic carbon storage in Swedish agricultural soils due to unexpected socio-economic drivers

    NASA Astrophysics Data System (ADS)

    Poeplau, C.; Bolinder, M. A.; Eriksson, J.; Lundblad, M.; Kätterer, T.

    2015-06-01

    Soil organic carbon (SOC) plays a crucial role in the global carbon cycle as a potential sink or source. Land management influences SOC storage, so the European Parliament decided in 2013 that changes in carbon stocks within a certain land use type, including arable land, must be reported by all member countries in their national inventory reports for greenhouse gas emissions. Here we show the temporal dynamics of SOC during the past 2 decades in Swedish agricultural soils, based on soil inventories conducted in 1988-1997 (Inventory I), 2001-2007 (Inventory II) and from 2010 onwards (Inventory III), and link SOC changes with trends in agricultural management. From Inventory I to Inventory II, SOC increased in 16 out of 21 Swedish counties, while from Inventory I to Inventory III it increased in 18 out of 21 counties. Mean topsoil (0-20 cm) SOC concentration for the entire country increased from 2.48 to 2.67% C (a relative increase of 7.7%, or 0.38% yr-1) over the whole period. We attributed this to a substantial increase in ley as a proportion of total agricultural area in all counties. The horse population in Sweden has more than doubled since 1981 and was identified as the main driver for this management change (R2 = 0.72). Due to subsidies introduced in the early 1990s, the area of long-term set-aside (mostly old leys) also contributed to the increase in area of ley. The carbon sink function of Swedish agricultural soils demonstrated in this study differs from trends found in neighbouring countries. This indicates that country-specific or local socio-economic drivers for land management must be accounted for in larger-scale predictions.

  1. Effects of multi-walled carbon nanotubes on mineralization and mobility of nonylphenol and sodium dodecyl sulfate in agricultural soils

    NASA Astrophysics Data System (ADS)

    Lillotte, Julia; Marschner, Bernd; Stumpe, Britta

    2014-05-01

    Nanotechnology is one of the major scientific research fields in this decade. One of the most wide-spread nanomaterials are carbon based nanoparticles (CNPs) which are increasingly be used in industry. Several studies shows that CNPs are interacting with other chemical compounds and organic pollutants in the environment. It is assumed that the interactions between CNPs and organic pollutants are affected by solution and aggregate behavior. Based on the knowledge of the behavior of CNPs and organic pollutants in aquatic systems the interactions of CNPs and organic pollutants in agricultural soils have to be studied. As organic pollutants two environmental substances, nonylphenol (NP) and sodium dodecyl sulfate (SDS) were selected as model substances. They occur frequently in aqueous systems and also show different solubility behavior. As CNP representatives, two different multi-walled carbon nanotubes (MWNT) were selected. They differed either in length or outer diameter. Conclusions therefrom are to be closed the influence of length and diameter of the sorption capacity of different organic pollutants. In addition, two agricultural soils (sandy and silty soil) and one forest soil (sandy soil) were chosen. Mineralization and sorption experiments were conducted to provide information about the degradation of organic pollutants in presence of multi-walled carbon nanotubes in soils. To analyze the CNPs mineralization potential, peroxidase activity was measured. Further extraction experiments were conducted to detect the extractable part of organic pollutants. The results show that the surface area of the MWNT has a significant impact on the sorption behav-ior of NP and SDS in soils. The sorption of NP and SDS is much higher than without MWNT. However, the properties of the organic pollutants (different water solubility and hydrophobicity) are equally important and should be noted. The degradation of both pollutants is influenced by MWNT. Due to the strong sorption of

  2. Global pattern of soil carbon losses due to the conversion of forests to agricultural land

    PubMed Central

    Wei, Xiaorong; Shao, Mingan; Gale, William; Li, Linhai

    2014-01-01

    Several reviews have analyzed the factors that affect the change in soil organic C (SOC) when forest is converted to agricultural land; however, the effects of forest type and cultivation stage on these changes have generally been overlooked. We collated observations from 453 paired or chronosequential sites where forests have been converted to agricultural land and then assessed the effects of forest type, cultivation stage, climate factors, and soil properties on the change in the SOC stock and the SOC turnover rate constant (k). The percent decrease in SOC stocks and the turnover rate constants both varied significantly according to forest type and cultivation stage. The largest decrease in SOC stocks was observed in temperate regions (52% decrease), followed by tropical regions (41% decrease) and boreal regions (31% decrease). Climate and soil factors affected the decrease in SOC stocks. The SOC turnover rate constant after the conversion of forests to agricultural land increased with the mean annual precipitation and temperature. To our knowledge, this is the first time that original forest type was considered when evaluating changes in SOC after being converted to agricultural land. The differences between forest types should be considered when calculating global changes in SOC stocks. PMID:24513580

  3. Land use and land management effects on soil organic carbon stock in Mediterranean agricultural areas (Southern Spain)

    NASA Astrophysics Data System (ADS)

    Parras-Alcántara, Luis; Lozano-García, Beatriz

    2014-05-01

    INTRODUCTION Soils play a key role in the carbon geochemical cycle. Agriculture contributes to carbon sequestration through photosynthesis and the incorporation of carbon into carbohydrates. Soil management is one of the best tools for climate change mitigation. Small increases or decreases in soil carbon content due to changes in land use or management practices, may result in a significant net exchange of carbon between the soil carbon pool and the atmosphere. In the last decades arable crops (AC) have been transformed into olive grove cultivations (OG) or vineyards (V) in Mediterranean areas. A field study was conducted to determine long-term effects of land use change (LUC) (AC by OG and V) on soil organic carbon (SOC), total nitrogen (TN), C:N ratio and their stratification in Calcic-Chromic Luvisols (LVcc/cr) in Mediterranean conditions. MATERIAL AND METHODS An unirrigated farm in Montilla-Moriles (Córdoba, Spain) cultivated under conventional tillage (animal power with lightweight reversible plows and non-mineral fertilization or pesticides) was selected for study in 1965. In 1966, the farm was divided into three plots with three different uses (AC, OG and V). The preliminary analyses were realized in 1965 for AC (AC1), and the second analyses were realized in 2011 for AC (AC2 - winter crop rotation with annual wheat and barley, receiving mineral fertilization or pesticides), OG (annual passes with disk harrow and cultivator in the spring, followed by a tine harrow in the summer receiving mineral fertilization and weed control with residual herbicides), and V (with three or five chisel passes a year from early spring to early autumn with mineral fertilization or pesticides.). In all cases (AC1, AC2, OG and V) were collected soil entire profiles. Soil properties determined were: soil particle size, bulk density, SOC, TN, C:N ratio, stocks and SRs. The statistical significance of the differences in the variables between land use practices was tested using the

  4. Empirical relationships for soil organic carbon transport from agricultural watersheds in Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improved quantification is needed for long-term soil organic carbon (SOC) transport in runoff at watershed scales. Coshocton wheel samplers were used to collect runoff samples from no-till and chisel-till watersheds in corn (Zea mays) and soybean (Glycine max) rotations over 13 years. Samples were a...

  5. Modelling soil carbon in agricultural systems: a way to widen the experimental space

    NASA Astrophysics Data System (ADS)

    O'Leary, Garry; Li Liu, De; Nuttall, James; Rajin Anwar, Muhuddin; Robertson, Fiona

    2015-07-01

    Mechanistic and explanatory simulation models provide robust and objective methods to extrapolate likely responses of crops and soils to climate change over different landscapes and time periods. Central to such simulation models are the supply of mineralised nutrients, in particular nitrogen, to crops through linked crop and nutrient sub-models that is achieved through modelling soil carbon dynamics. Attention to soil processes is therefore an essential part of building robust and sustainable production systems and understanding the potential impacts of climate change. To the farmer, focus must be on the productive capacity of the land and its rejuvenation to sustain production. In the broader context of reducing atmospheric CO2 concentration through soil C sequestration, understanding soil processes and the immediate environment likewise require attention to productivity issues. This is because without maintaining productivity a better understanding of soil organic carbon (SOC) processes is unlikely to lead to increased SOC sequestration in Australia's farming land. Some gaps in knowledge of how to manage SOC are being addressed in a national research effort, including the scant measured data against which models can be tested. Nevertheless, continuing to apply models to push the boundaries well beyond what can be achieved in practice widens the experimental space, allowing new ideas to be tested where physical experiments are not possible. This raises optimism that new ways may be discovered to explain change in SOC and increase SOC where it is possible in a beneficial way.

  6. Spatially governed climate factors dominate management in determining the quantity and distribution of soil organic carbon in dryland agricultural systems

    NASA Astrophysics Data System (ADS)

    Hoyle, Frances C.; O’Leary, Rebecca A.; Murphy, Daniel V.

    2016-08-01

    Few studies describe the primary drivers influencing soil organic carbon (SOC) stocks and the distribution of carbon (C) fractions in agricultural systems from semi-arid regions; yet these soils comprise one fifth of the global land area. Here we identified the primary drivers for changes in total SOC and associated particulate (POC), humus (HOC) and resistant (ROC) organic C fractions for 1347 sample points in the semi-arid agricultural region of Western Australia. Total SOC stock (0–0.3 m) varied from 4 to 209 t C ha‑1 with 79% of variation explained by measured variables. The proportion of C in POC, HOC and ROC fractions averaged 28%, 45% and 27% respectively. Climate (43%) and land management practices (32%) had the largest relative influence on variation in total SOC. Carbon accumulation was constrained where average daily temperature was above 17.2 °C and annual rainfall below 450 mm, representing approximately 42% of the 197,300 km2 agricultural region. As such large proportions of this region are not suited to C sequestration strategies. For the remainder of the region a strong influence of management practices on SOC indicate opportunities for C sequestration strategies associated with incorporation of longer pasture phases and adequate fertilisation.

  7. Spatially governed climate factors dominate management in determining the quantity and distribution of soil organic carbon in dryland agricultural systems.

    PubMed

    Hoyle, Frances C; O'Leary, Rebecca A; Murphy, Daniel V

    2016-01-01

    Few studies describe the primary drivers influencing soil organic carbon (SOC) stocks and the distribution of carbon (C) fractions in agricultural systems from semi-arid regions; yet these soils comprise one fifth of the global land area. Here we identified the primary drivers for changes in total SOC and associated particulate (POC), humus (HOC) and resistant (ROC) organic C fractions for 1347 sample points in the semi-arid agricultural region of Western Australia. Total SOC stock (0-0.3 m) varied from 4 to 209 t C ha(-1) with 79% of variation explained by measured variables. The proportion of C in POC, HOC and ROC fractions averaged 28%, 45% and 27% respectively. Climate (43%) and land management practices (32%) had the largest relative influence on variation in total SOC. Carbon accumulation was constrained where average daily temperature was above 17.2 °C and annual rainfall below 450 mm, representing approximately 42% of the 197,300 km(2) agricultural region. As such large proportions of this region are not suited to C sequestration strategies. For the remainder of the region a strong influence of management practices on SOC indicate opportunities for C sequestration strategies associated with incorporation of longer pasture phases and adequate fertilisation.

  8. Spatially governed climate factors dominate management in determining the quantity and distribution of soil organic carbon in dryland agricultural systems

    PubMed Central

    Hoyle, Frances C.; O’Leary, Rebecca A.; Murphy, Daniel V.

    2016-01-01

    Few studies describe the primary drivers influencing soil organic carbon (SOC) stocks and the distribution of carbon (C) fractions in agricultural systems from semi-arid regions; yet these soils comprise one fifth of the global land area. Here we identified the primary drivers for changes in total SOC and associated particulate (POC), humus (HOC) and resistant (ROC) organic C fractions for 1347 sample points in the semi-arid agricultural region of Western Australia. Total SOC stock (0–0.3 m) varied from 4 to 209 t C ha−1 with 79% of variation explained by measured variables. The proportion of C in POC, HOC and ROC fractions averaged 28%, 45% and 27% respectively. Climate (43%) and land management practices (32%) had the largest relative influence on variation in total SOC. Carbon accumulation was constrained where average daily temperature was above 17.2 °C and annual rainfall below 450 mm, representing approximately 42% of the 197,300 km2 agricultural region. As such large proportions of this region are not suited to C sequestration strategies. For the remainder of the region a strong influence of management practices on SOC indicate opportunities for C sequestration strategies associated with incorporation of longer pasture phases and adequate fertilisation. PMID:27530805

  9. Spatially governed climate factors dominate management in determining the quantity and distribution of soil organic carbon in dryland agricultural systems.

    PubMed

    Hoyle, Frances C; O'Leary, Rebecca A; Murphy, Daniel V

    2016-01-01

    Few studies describe the primary drivers influencing soil organic carbon (SOC) stocks and the distribution of carbon (C) fractions in agricultural systems from semi-arid regions; yet these soils comprise one fifth of the global land area. Here we identified the primary drivers for changes in total SOC and associated particulate (POC), humus (HOC) and resistant (ROC) organic C fractions for 1347 sample points in the semi-arid agricultural region of Western Australia. Total SOC stock (0-0.3 m) varied from 4 to 209 t C ha(-1) with 79% of variation explained by measured variables. The proportion of C in POC, HOC and ROC fractions averaged 28%, 45% and 27% respectively. Climate (43%) and land management practices (32%) had the largest relative influence on variation in total SOC. Carbon accumulation was constrained where average daily temperature was above 17.2 °C and annual rainfall below 450 mm, representing approximately 42% of the 197,300 km(2) agricultural region. As such large proportions of this region are not suited to C sequestration strategies. For the remainder of the region a strong influence of management practices on SOC indicate opportunities for C sequestration strategies associated with incorporation of longer pasture phases and adequate fertilisation. PMID:27530805

  10. Effects of carbon-based nanoparticles (CNPs) on the fate of endocrine disrupting chemicals (EDCs) in different agricultural soils.

    NASA Astrophysics Data System (ADS)

    Stumpe, Britta; Wolski, Sabrina; Marschner, Bernd

    2013-04-01

    Nanotechnology is a major innovative scientific and economic growth area. To date there is a lack about possible adverse effects that may be associated with manufactured nanomaterial in terrestrial environments. Since it is known that on the one hand carbon-based nanoparticles (CNPs) and endocrine disrupting chemicals (EDCs) strongly interact in wastewater and that on the other hand CNPs and EDCs are released together via wastewater irrigation to agricultural soils, knowledge of CNP effects on the EDC fate in the soil environment is needed for further risk assessments. The overall goal of this project is to gain a better understanding of interaction of CNPs with EDCs within the soil system. Three different soil samples were applied with different CNPs, EDCs and CNP-EDC complexes and incubated over a period of 6 weeks. The EDC mineralization as well as their uptake by soil microorganisms was monitored to describe impacts of the nanomaterial on the EDC fate. As quality control for the biological soil activity soil respiration, enzyme activities and the soil microbial biomass were monitored in all incubated soil samples. Clearly, EDCs bound in CNP complexes showed a decrease in mineralization. While the free EDCs showed a total mineralization of 34 to 45 %, the nano complexed EDCs were only mineralized to 12 to 15 %. Since no effects of the nanomaterial on the biological soil activity were observed, we conclude that the reduced EDC mineralization is directly linked to their interaction with the CNPs. Since additionally the EDC adsorption to CNPs reduced the EDC uptake by soil microorganism, we assume that CNPs generally form more or less recalcitrant aggregates which likely protect the associated EDCs from degradation.

  11. The role of soil microbes in the global carbon cycle: tracking the below-ground microbial processing of plant-derived carbon for manipulating carbon dynamics in agricultural systems.

    PubMed

    Gougoulias, Christos; Clark, Joanna M; Shaw, Liz J

    2014-09-01

    It is well known that atmospheric concentrations of carbon dioxide (CO2) (and other greenhouse gases) have increased markedly as a result of human activity since the industrial revolution. It is perhaps less appreciated that natural and managed soils are an important source and sink for atmospheric CO2 and that, primarily as a result of the activities of soil microorganisms, there is a soil-derived respiratory flux of CO2 to the atmosphere that overshadows by tenfold the annual CO2 flux from fossil fuel emissions. Therefore small changes in the soil carbon cycle could have large impacts on atmospheric CO2 concentrations. Here we discuss the role of soil microbes in the global carbon cycle and review the main methods that have been used to identify the microorganisms responsible for the processing of plant photosynthetic carbon inputs to soil. We discuss whether application of these techniques can provide the information required to underpin the management of agro-ecosystems for carbon sequestration and increased agricultural sustainability. We conclude that, although crucial in enabling the identification of plant-derived carbon-utilising microbes, current technologies lack the high-throughput ability to quantitatively apportion carbon use by phylogentic groups and its use efficiency and destination within the microbial metabolome. It is this information that is required to inform rational manipulation of the plant-soil system to favour organisms or physiologies most important for promoting soil carbon storage in agricultural soil. PMID:24425529

  12. The role of soil microbes in the global carbon cycle: tracking the below-ground microbial processing of plant-derived carbon for manipulating carbon dynamics in agricultural systems.

    PubMed

    Gougoulias, Christos; Clark, Joanna M; Shaw, Liz J

    2014-09-01

    It is well known that atmospheric concentrations of carbon dioxide (CO2) (and other greenhouse gases) have increased markedly as a result of human activity since the industrial revolution. It is perhaps less appreciated that natural and managed soils are an important source and sink for atmospheric CO2 and that, primarily as a result of the activities of soil microorganisms, there is a soil-derived respiratory flux of CO2 to the atmosphere that overshadows by tenfold the annual CO2 flux from fossil fuel emissions. Therefore small changes in the soil carbon cycle could have large impacts on atmospheric CO2 concentrations. Here we discuss the role of soil microbes in the global carbon cycle and review the main methods that have been used to identify the microorganisms responsible for the processing of plant photosynthetic carbon inputs to soil. We discuss whether application of these techniques can provide the information required to underpin the management of agro-ecosystems for carbon sequestration and increased agricultural sustainability. We conclude that, although crucial in enabling the identification of plant-derived carbon-utilising microbes, current technologies lack the high-throughput ability to quantitatively apportion carbon use by phylogentic groups and its use efficiency and destination within the microbial metabolome. It is this information that is required to inform rational manipulation of the plant-soil system to favour organisms or physiologies most important for promoting soil carbon storage in agricultural soil.

  13. The role of soil microbes in the global carbon cycle: tracking the below-ground microbial processing of plant-derived carbon for manipulating carbon dynamics in agricultural systems

    PubMed Central

    Gougoulias, Christos; Clark, Joanna M; Shaw, Liz J

    2014-01-01

    It is well known that atmospheric concentrations of carbon dioxide (CO2) (and other greenhouse gases) have increased markedly as a result of human activity since the industrial revolution. It is perhaps less appreciated that natural and managed soils are an important source and sink for atmospheric CO2 and that, primarily as a result of the activities of soil microorganisms, there is a soil-derived respiratory flux of CO2 to the atmosphere that overshadows by tenfold the annual CO2 flux from fossil fuel emissions. Therefore small changes in the soil carbon cycle could have large impacts on atmospheric CO2 concentrations. Here we discuss the role of soil microbes in the global carbon cycle and review the main methods that have been used to identify the microorganisms responsible for the processing of plant photosynthetic carbon inputs to soil. We discuss whether application of these techniques can provide the information required to underpin the management of agro-ecosystems for carbon sequestration and increased agricultural sustainability. We conclude that, although crucial in enabling the identification of plant-derived carbon-utilising microbes, current technologies lack the high-throughput ability to quantitatively apportion carbon use by phylogentic groups and its use efficiency and destination within the microbial metabolome. It is this information that is required to inform rational manipulation of the plant–soil system to favour organisms or physiologies most important for promoting soil carbon storage in agricultural soil. PMID:24425529

  14. Towards a more comprehensive modelling framework to quantify vertical and lateral carbon fluxes in the agricultural soils of the EU

    NASA Astrophysics Data System (ADS)

    Lugato, Emanuele; Paustian, Keith; Panagos, Panos; Jones, Arwyn; Borrelli, Pasquale

    2016-04-01

    Under the international protocols aiming at reducing the climate change impact, the land use sector is, likely, one of most complex to be accounted for greenhouse gas (GHG) emission and removal. This is related to its fragmentation and the complex biogeochemical feedbacks interacting with the human activity. Among those feedbacks, the role of erosion in the global carbon (C) cycle is not totally disentangled, leading to disagreement whether this process induces lands to be a source or sink of CO2. To investigate this issue, we coupled soil erosion into a biogeochemistry model, running at 1 km2 resolution across the agricultural soils of the European Union (EU). Based on data-driven assumptions, the simulation took into account also soil deposition within grid cells and the potential C export to riverine systems, in a way to be conservative in a mass balance. We estimated that 143 out of 187 Mha have C erosion rates <0.05 Mg C ha-1 yr-1, although some hot-spot areas showed eroded soil organic C >0.45 Mg C ha-1 yr-1. Exploring different assumptions on short-term enhancement C mineralization during soil displacement/transport, enrichment factor of eroded C and sub-soil organic C composition, we estimated an average net CO2 flux ranging from -2.28 (source) to +3.73 (sink) Tg yr-1 of CO2eq, in comparison with a baseline without erosion. Moreover, the erosion-induced sink of atmospheric carbon was comprised between 0 to 50% of the carbon transported by erosion and varied markedly across the EU. While we first integrated most of all relevant processes and C fluxes in a comprehensive model framework, additional experimental data need to be collected for representing specific processes in a more mechanistic way.

  15. Soil water and carbon management for agricultural resilience in a key node in the global virtual water trade network: Mato Grosso, Brazil

    NASA Astrophysics Data System (ADS)

    Johnson, M. S.; Speratti, A. B.; Lathuilliere, M. J.; Dalmagro, H. J.; Couto, E. G.

    2015-12-01

    The Amazon region is globally connected through agricultural exports, with the Brazilian state of Mato Grosso in particular emerging as a key node in the global virtual water trade network in recent years, based largely on rainfed agriculture. The anticipated growth in the world's population suggests that virtual water trade will only become more important to global food security. In this presentation we will evaluate strategies for improving the resilience of rainfed agriculture in the region, particularly for the nearly 12 million hectares of sandy soil with low water holding capacity within Mato Grosso that has largely been converted to agricultural use. We will review land use change trajectories and present results from soil water balance modeling and carbon fluxes for a range of future scenarios, including continued agricultural extensification, potential strategies for agricultural intensification, and novel water and carbon management strategies including biochar use in sandy soils to improve soil water holding capacities and soil carbon sequestration. We will also consider the role that irrigation might play in the future in the Amazon for improving agricultural resilience to climate change and feedbacks between irrigation and land use change pressures, noting that groundwater resources in the region are presently among the least exploited on the planet.

  16. Carbon Sequestration Potential of Agricultural Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Through proper management, agricultural systems (cropland, pasture, and forest) have the ability to remove carbon dioxide from the atmosphere and sequester it in soils and wood products. The carbon thus sequestered can help slow the increase in atmospheric carbon dioxide currently occurring as a res...

  17. Using U-series Isotopes To Determine Sources Of Pedogenic Carbonates: Comparison Of Natural And Agricultural Soils In The Semi-arid Southern New Mexico And Western Texas

    NASA Astrophysics Data System (ADS)

    Nyachoti, S. K.; Ma, L.; Borrok, D. M.; Jin, L.; Tweedie, C. E.

    2012-12-01

    Pedogenic carbonates commonly precipitate from infiltrating soil water in arid and semi-arid lands and are observed in soils of southern New Mexico and western Texas. These carbonates could form an impermeable layer in the soil horizons impairing water infiltration, thus affecting crop growth and yield. It is important to determine the source of C and Ca in these carbonates and to understand conditions favoring their formation, kinetics and precipitation rates. In this study, major elements and U-series isotopes in bulk calcic soils, and weak acid leachates and residues were measured from one irrigated alfalfa site in the Hueco basin near El Paso, TX and one natural shrubland site on the USDA Jornada experimental range in southern NM. The combined geochemical and isotopic results allow us to determine the formation ages of the carbonates; investigate the mobility of U, Th, and major elements in these soils; and infer for the effects of irrigation on carbonate formation in agricultural soils. Our results show distinctive U and Th isotope systems in the two soil profiles analyzed. For example, (234U/238U) ratios in the Jornada bulk soils decrease from ~1.01 to 0.96 towards the surface, consistent with a preferential loss of 234U over 238U during chemical weathering. At the Jornada site, (238U/232Th) ratios decrease while (230Th/238U) increase towards the surface, consistent with a general depletion of U and the immobility of Th in the natural soils. By contrast at the Alfalfa site, (234U/238U) ratios of bulk soils increase from ~ 0.97 to 1.02 towards the surface, suggesting an additional source of external uranium, most likely the irrigation water from Rio Grande which has a (234U/238U) ratio of ~ 1.5 near El Paso. The (238U/232Th) and (230Th/238U) ratios also imply leaching of U from shallower soils but precipitation in greater depths at Alfalfa site; suggests that partial dissolution and re-precipitation of younger carbonates occur. Calculated carbonate ages from U

  18. Impacts of agricultural management and climate change on future soil organic carbon dynamics in North China Plain.

    PubMed

    Wang, Guocheng; Li, Tingting; Zhang, Wen; Yu, Yongqiang

    2014-01-01

    Dynamics of cropland soil organic carbon (SOC) in response to different management practices and environmental conditions across North China Plain (NCP) were studied using a modeling approach. We identified the key variables driving SOC changes at a high spatial resolution (10 km × 10 km) and long time scale (90 years). The model used future climatic data from the FGOALS model based on four future greenhouse gas (GHG) concentration scenarios. Agricultural practices included different rates of nitrogen (N) fertilization, manure application, and stubble retention. We found that SOC change was significantly influenced by the management practices of stubble retention (linearly positive), manure application (linearly positive) and nitrogen fertilization (nonlinearly positive) - and the edaphic variable of initial SOC content (linearly negative). Temperature had weakly positive effects, while precipitation had negligible impacts on SOC dynamics under current irrigation management. The effects of increased N fertilization on SOC changes were most significant between the rates of 0 and 300 kg ha-1 yr-1. With a moderate rate of manure application (i.e., 2000 kg ha-1 yr-1), stubble retention (i.e., 50%), and an optimal rate of nitrogen fertilization (i.e., 300 kg ha-1 yr-1), more than 60% of the study area showed an increase in SOC, and the average SOC density across NCP was relatively steady during the study period. If the rates of manure application and stubble retention doubled (i.e., manure application rate of 4000 kg ha-1 yr-1 and stubble retention rate of 100%), soils across more than 90% of the study area would act as a net C sink, and the average SOC density kept increasing from 40 Mg ha-1 during 2010s to the current worldwide average of ∼ 55 Mg ha-1 during 2060s. The results can help target agricultural management practices for effectively mitigating climate change through soil C sequestration.

  19. Dissolved organic carbon concentrations and compositions, and trihalomethane formation potentials in waters from agricultural peat soils, Sacramento-San Joaquin Delta, California; implications for drinking-water quality

    USGS Publications Warehouse

    Fujii, Roger; Ranalli, Anthony J.; Aiken, George R.; Bergamaschi, Brian A.

    1998-01-01

    Water exported from the Sacramento-San Joaquin River delta (Delta) is an important drinking-water source for more than 20 million people in California. At times, this water contains elevated concentrations of dissolved organic carbon and bromide, and exceeds the U.S. Environmental Protection Agency's maximum contaminant level for trihalomethanes of 0.100 milligrams per liter if chlorinated for drinking water. About 20 to 50 percent of the trihalomethane precursors to Delta waters originates from drainage water from peat soils on Delta islands. This report elucidates some of the factors and processes controlling and affecting the concentration and quality of dissolved organic carbon released from peat soils and relates the propensity of dissolved organic carbon to form trihalomethanes to its chemical composition.Soil water was sampled from near-surface, oxidized, well-decomposed peat soil (upper soil zone) and deeper, reduced, fibrous peat soil (lower soil zone) from one agricultural field in the west central Delta over 1 year. Concentrations of dissolved organic carbon in the upper soil zone were highly variable, with median concentrations ranging from 46.4 to 83.2 milligrams per liter. Concentrations of dissolved organic carbon in samples from the lower soil zone were much less variable and generally slightly higher than samples from the upper soil zone, with median concentrations ranging from 49.3 to 82.3 milligrams per liter. The dissolved organic carbon from the lower soil zone had significantly higher aromaticity (as measured by specific ultraviolet absorbance) and contained significantly greater amounts of aromatic humic substances (as measured by XAD resin fractionation and carbon-13 nuclear magnetic resonance analysis of XAD isolates) than the dissolved organic carbon from the upper soil zone. These results support the conclusion that more aromatic forms of dissolved organic carbon are produced under anaerobic conditions compared to aerobic conditions

  20. Impact of soybean stover- and pine needle-derived biochars on Pb and As mobility, microbial community, and carbon stability in a contaminated agricultural soil.

    PubMed

    Ahmad, Mahtab; Ok, Yong Sik; Kim, Byung-Yong; Ahn, Jae-Hyung; Lee, Young Han; Zhang, Ming; Moon, Deok Hyun; Al-Wabel, Mohammad I; Lee, Sang Soo

    2016-01-15

    Biochar is gaining attention as a potential soil amendment to remediate and revitalize the contaminated soils. Simultaneous effects of biochar on metals mobility, microbial abundance, bacterial diversity and carbon storage in soil are scarcely addressed. This study assessed the effect of biochars on metal mobility, microbial abundance, bacterial community, and carbon storage in an agricultural soil contaminated with heavy metals. Biochars derived from soybean stover at 300 and 700 °C (S-BC300 and S-BC700, respectively) and pine needles at the same temperatures (P-BC300 and P-BC700, respectively) were used. A maximum reduction of Pb mobility by 95% was observed from a soil treated with S-BC700, associated with precipitation of chloropyromorphite and hydroxylpyromorphite. In contrast, As was desorbed from soil particles because of P competition. The abundance of Gram-positive and negative bacteria, fungi, actinomycetes, and arbuscular mycorrhizal fungi increased in the soils treated with biochar produced at 300 °C, possibly due to the high dissolved organic and active organic carbons. Microbial abundance in the soils treated with S-BC700 and P-BC700 was constant due to the existence of fixed or non-labile carbon. Changes to bacterial communities in the biochar-treated soils depended on feedstock type and pyrolysis temperature. Actinobacteria substantially increased whereas Acidobacteria and Chloroflexi decreased in the biochar-treated soils. The non-labile carbon fraction was ∼25 fold higher in the biochar-treated soil than the control soil, indicating long-term carbon storage. PMID:26496843

  1. Impact of soybean stover- and pine needle-derived biochars on Pb and As mobility, microbial community, and carbon stability in a contaminated agricultural soil.

    PubMed

    Ahmad, Mahtab; Ok, Yong Sik; Kim, Byung-Yong; Ahn, Jae-Hyung; Lee, Young Han; Zhang, Ming; Moon, Deok Hyun; Al-Wabel, Mohammad I; Lee, Sang Soo

    2016-01-15

    Biochar is gaining attention as a potential soil amendment to remediate and revitalize the contaminated soils. Simultaneous effects of biochar on metals mobility, microbial abundance, bacterial diversity and carbon storage in soil are scarcely addressed. This study assessed the effect of biochars on metal mobility, microbial abundance, bacterial community, and carbon storage in an agricultural soil contaminated with heavy metals. Biochars derived from soybean stover at 300 and 700 °C (S-BC300 and S-BC700, respectively) and pine needles at the same temperatures (P-BC300 and P-BC700, respectively) were used. A maximum reduction of Pb mobility by 95% was observed from a soil treated with S-BC700, associated with precipitation of chloropyromorphite and hydroxylpyromorphite. In contrast, As was desorbed from soil particles because of P competition. The abundance of Gram-positive and negative bacteria, fungi, actinomycetes, and arbuscular mycorrhizal fungi increased in the soils treated with biochar produced at 300 °C, possibly due to the high dissolved organic and active organic carbons. Microbial abundance in the soils treated with S-BC700 and P-BC700 was constant due to the existence of fixed or non-labile carbon. Changes to bacterial communities in the biochar-treated soils depended on feedstock type and pyrolysis temperature. Actinobacteria substantially increased whereas Acidobacteria and Chloroflexi decreased in the biochar-treated soils. The non-labile carbon fraction was ∼25 fold higher in the biochar-treated soil than the control soil, indicating long-term carbon storage.

  2. Soil Enzyme Activities, Microbial Communities and Carbon and Nitrogen Availability in Organic Agroecosystems Across an Intensively-Managed Agricultural Landscape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variability in the activity and composition of soil microbial communities may have important implications for the suite of microbially-derived ecosystem functions upon which agricultural systems rely, particularly organic agriculture. An on-farm approach was used to investigate microbial communitie...

  3. Conservation agriculture among small scale farmers in semi-arid region of Kenya does improve soil biological quality and soil organic carbon

    NASA Astrophysics Data System (ADS)

    Waweru, Geofrey; Okoba, Barrack; Cornelis, Wim

    2016-04-01

    The low food production in Sub-Saharan Africa (SSA) has been attributed to declining soil quality. This is due to soil degradation and fertility depletion resulting from unsustainable conventional farming practices such as continuous tillage, crop residue burning and mono cropping. To overcome these challenges, conservation agriculture (CA) is actively promoted. However, little has been done in evaluating the effect of each of the three principles of CA namely: minimum soil disturbance, maximum surface cover and diversified/crop rotation on soil quality in SSA. A study was conducted for three years from 2012 to 2015 in Laikipia East sub county in Kenya to evaluate the effect of tillage, surface cover and intercropping on a wide variety of physical, chemical and biological soil quality indicators, crop parameters and the field-water balance. This abstract reports on soil microbial biomass carbon (SMBC) and soil organic carbon (SOC). The experimental set up was a split plot design with tillage as main treatment (conventional till (CT), no-till (NT) and no-till with herbicide (NTH)), and intercropping and surface cover as sub treatment (intercropping maize with: beans, MB; beans and leucaena, MBL; beans and maize residues at 1.5 Mg ha-1 MBMu, and dolichos, MD). NT had significantly higher SMBC by 66 and 31% compared with CT and NTH respectively. SOC was significantly higher in NTH than CT and NT by 15 and 4%, respectively. Intercropping and mulching had significant effect on SMBC and SOC. MBMu resulted in higher SMBC by 31, 38 and 43%, and SOC by 9, 20 and 22% as compared with MBL, MD and MB, respectively. SMBC and SOC were significantly affected by the interaction between tillage, intercropping and soil cover with NTMBMu and NTHMBMu having the highest SMBC and SOC, respectively. We conclude that indeed tillage, intercropping and mulching substantially affect SMBC and SOC. On the individual components of CA, tillage and surface cover had the highest effect on SMBC and

  4. Soil Erosion and Agricultural Sustainability

    NASA Astrophysics Data System (ADS)

    Montgomery, D. R.

    2009-04-01

    Data drawn from a global compilation of studies support the long articulated contention that erosion rates from conventionally plowed agricultural fields greatly exceed rates of soil production, erosion under native vegetation, and long-term geological erosion. Whereas data compiled from around the world show that soil erosion under conventional agriculture exceeds both rates of soil production and geological erosion rates by up to several orders of magnitude, similar global distributions of soil production and geological erosion rates suggest an approximate balance. Net soil erosion rates in conventionally plowed fields on the order of 1 mm/yr can erode typical hillslope soil profiles over centuries to millennia, time-scales comparable to the longevity of major civilizations. Well-documented episodes of soil loss associated with agricultural activities date back to the introduction of erosive agricultural methods in regions around the world, and stratigraphic records of accelerated anthropogenic soil erosion have been recovered from lake, fluvial, and colluvial stratigraphy, as well as truncation of soil stratigraphy (such as truncated A horizons). A broad convergence in the results from studies based on various approaches employed to study ancient soil loss and rates of downstream sedimentation implies that widespread soil loss has accompanied human agricultural intensification in examples drawn from around the world. While a broad range of factors, including climate variability and society-specific social and economic contexts — such as wars or colonial relationships — all naturally influence the longevity of human societies, the ongoing loss of topsoil inferred from studies of soil erosion rates in conventional agricultural systems has obvious long-term implications for agricultural sustainability. Consequently, modern agriculture — and therefore global society — faces a fundamental question over the upcoming centuries. Can an agricultural system

  5. Comparison of models for determining soil-surface carbon dioxide effluxes in different agricultural systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil-surface CO2 efflux (SCE) models are appealing due to expense and labor of fine temporal- and spatial-resolution field measurements. However, several simple SCE models are reported in the literature. Our objective was to compare and validate selected soil temperature (Ts)- and water content ('v)...

  6. Nitrogen and carbon pools in an agricultural soil amended with natural and NH4-enriched K-Chabazite zeolitite

    NASA Astrophysics Data System (ADS)

    Ferretti, Giacomo; Faccini, Barbara; Vittori Antisari, Livia; Di Giuseppe, Dario; Massimo, Coltorti

    2015-04-01

    Nitrogen and Carbon pools in a reclaimed agricultural soil amended with 5 to 15 Kg m-2 of natural and NH4-enriched (K-Chabazite) zeolitites have been investigated. Zeolitites were enriched by means of static exchange with a swine slurry in a prototype (ZeoLIFE Project, www.zeolife.it). The experimental field is located in the Po Delta plain near Codigoro (Ferrara, Italy), it extends over an area of about 6 ha and it was divided in six parcels. The field has been heavily fertilized with chemical fertilizers and livestock sewage since 1960. Nowadays the area is part of the Nitrate Vulnerable Zones (Nitrate Directive 91/676/CEE) and a maximum annual input of 170 Kg-N ha-1 must be respected. With respect to the control parcels, at the end of the agronomic year, sorghum yield was 4% and 14% higher in the parcels treated with natural zeolitite and in that treated with NH4-enriched zeolitite, respectively. This notwithstanding the N fertilizers reduction from 30% in the former to 50% in the latter. Beside the yield improvement, N and C pools are affected by the use of zeolitite and relevant changes have been noticed. i) δ15N ratios in both soil (total and fixed N-NH4 inside the clay interlayer and zeolite exchange sites) and different organs of the sorghum crops show that the N-NH4 stocked in the enriched zeolitite has been transferred to the crops and preferentially stocked in the leaves with respect to the N-NH4 provided by chemical fertilizer. ii) The active role of fixed N-NH4 pool in mineral nutrition of the crops and its replacement can be due to inorganic N fertilizers (Urea and Diammonium Phosphate). This pool in fact decreased during the crops growth, suggesting that it represented an important contribution to the active N pool in the soil. iii) Due to the high N content in this agricultural field, no significant total N decrease was observed during the growing season, which is also responsible for the low C/N ratio in the soil. After the N input from NH4

  7. Soil moisture: Some fundamentals. [agriculture - soil mechanics

    NASA Technical Reports Server (NTRS)

    Milstead, B. W.

    1975-01-01

    A brief tutorial on soil moisture, as it applies to agriculture, is presented. Information was taken from books and papers considered freshman college level material, and is an attempt to briefly present the basic concept of soil moisture and a minimal understanding of how water interacts with soil.

  8. Biosolids amendment dramatically increases sequestration of crop residue-carbon in agricultural soils in western Illinois

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Release of carbon dioxide through microbial respiration from the world’s crop residues (non-edible plant parts left in the field after harvest) represents an important form of carbon transfer from terrestrial ecosystems to the atmosphere. We hypothesized that alleviation of environmental stress (moi...

  9. On the rebound: soil organic carbon stocks can bounce back to near forest levels when agroforests replace agriculture in southern India

    NASA Astrophysics Data System (ADS)

    Hombegowda, H. C.; van Straaten, O.; Köhler, M.; Hölscher, D.

    2015-08-01

    Tropical agroforestry has an enormous potential to sequester carbon while simultaneously producing agricultural yields and tree products. The amount of soil organic carbon (SOC) sequestered is however influenced by the type of the agroforestry system established, the soil and climatic conditions and management. In this regional scale study, we utilized a chronosequence approach to investigate how SOC stocks changed when the original forests are converted to agriculture, and then subsequently to four different agroforestry systems (AFSs): homegarden, coffee, coconut and mango. In total we established 224 plots in 56 plot clusters across four climate zones in southern India. Each plot cluster consisted of four plots: a natural forest reference plot, an agriculture reference and two of the same AFS types of two ages (30-60 years and > 60 years). The conversion of forest to agriculture resulted in a large loss the original SOC stock (50-61 %) in the top meter of soil depending on the climate zone. The establishment of homegarden and coffee AFSs on agriculture land caused SOC stocks to rebound to near forest levels, while in mango and coconut AFSs the SOC stock increased only slightly above the agriculture stock. The most important variable regulating SOC stocks and its changes was tree basal area, possibly indicative of organic matter inputs. Furthermore, climatic variables such as temperature and precipitation, and soil variables such as clay fraction and soil pH were likewise all important regulators of SOC and SOC stock changes. Lastly, we found a strong correlation between tree species diversity in homegarden and coffee AFSs and SOC stocks, highlighting possibilities to increase carbon stocks by proper tree species assemblies.

  10. On the rebound: soil organic carbon stocks can bounce back to near forest levels when agroforests replace agriculture in southern India

    NASA Astrophysics Data System (ADS)

    Hombegowda, H. C.; van Straaten, O.; Köhler, M.; Hölscher, D.

    2016-01-01

    Tropical agroforestry has an enormous potential to sequester carbon while simultaneously producing agricultural yields and tree products. The amount of soil organic carbon (SOC) sequestered is influenced by the type of the agroforestry system established, the soil and climatic conditions, and management. In this regional-scale study, we utilized a chronosequence approach to investigate how SOC stocks changed when the original forests are converted to agriculture, and then subsequently to four different agroforestry systems (AFSs): home garden, coffee, coconut and mango. In total we established 224 plots in 56 plot clusters across 4 climate zones in southern India. Each plot cluster consisted of four plots: a natural forest reference, an agriculture reference and two of the same AFS types of two ages (30-60 years and > 60 years). The conversion of forest to agriculture resulted in a large loss the original SOC stock (50-61 %) in the top meter of soil depending on the climate zone. The establishment of home garden and coffee AFSs on agriculture land caused SOC stocks to rebound to near forest levels, while in mango and coconut AFSs the SOC stock increased only slightly above the agriculture SOC stock. The most important variable regulating SOC stocks and its changes was tree basal area, possibly indicative of organic matter inputs. Furthermore, climatic variables such as temperature and precipitation, and soil variables such as clay fraction and soil pH were likewise all important regulators of SOC and SOC stock changes. Lastly, we found a strong correlation between tree species diversity in home garden and coffee AFSs and SOC stocks, highlighting possibilities to increase carbon stocks by proper tree species assemblies.

  11. Remote sensing of soil carbon and greenhouse gas dynamics across agricultural landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate assessments of the overall impact of the GRACEnet strategies for enhancing soil C sequestration and reducing greenhouse gases emissions requires extending results from small plot of field experiments to regional and national scales. This spatial scaling task is nontrivial because the mechan...

  12. Carbon and 14C distribution in tropical and subtropical agricultural soils

    NASA Astrophysics Data System (ADS)

    Prastowo, Erwin; Grootes, Pieter; Nadeau, Marie

    2016-04-01

    Paddy soil management affects, through the alternating anoxic and oxic conditions it creates, the transport and stabilisation of soil organic matter (SOM). Irrigation water may percolate more organic materials - dissolved (DOM) and colloidal - into the subsoil during anoxic conditions. Yet a developed ploughpan tends to prevent C from going deeper in the subsoil and partly decouple C distribution in top and sub soil. We investigate the influence of different soil type and environment. We observed the C and 14C distribution in paddy and non-paddy soil profiles in three different soil types from four different climatic regions of tropical Indonesia, and subtropical China. Locations were Sukabumi (Andosol, ca. 850 m a.s.l), Bogor (clayey Alisol, ca. 240 m a.s.l), and Ngawi (Vertisol, ca. 70 m a.s.l) in Jawa, Indonesia, and Cixi (Alisol(sandy), ca. 4 - 6 m a.s.l) in Zhejiang Province, China. We compared rice paddies with selected neighbouring non-paddy fields and employed AMS 14C as a tool to study C dynamics from bulk, alkali soluble-humic, and insoluble humin samples, and macrofossils (plant remains, charcoal). Our data suggest that vegetation type determines the quantity and quality of biomass introduced as litter and root material in top and subsoil, and thus contributes to the soil C content and profile, which fits the 14C signal distribution, as well as 13C in Ngawi with C4 sugar cane as upland crop. 14C concentrations for the mobile humic acid fraction were generally higher than for bulk samples from the same depth, except when recent plant and root debris led to high 14C levels in near-surface samples. The difference in sampling, - averaged layer for bulk sample and 1-cm layer thickness for point sample - shows gradients in C and 14C across the layers, which could be a reason for discrepancies between the two. High 14C concentrations - in Andosol Sukabumi up to 111 pMC - exceed the atmospheric 14CO2concentration in the sampling year in 2012 (˜ 103 pMC) and

  13. Climate change impacts on agriculture and soil carbon sequestration potential in the Huang-Hai Plain of China

    SciTech Connect

    Thomson, Allison M.; Izaurralde, R Cesar C.; Rosenberg, Norman J.; He, Xiaoxia

    2006-03-01

    The Huang-Hai Plain in northeast China has been cultivated for thousands of years and is the most productive wheat growing region in the country. Its agricultural future will be determined in large part by how global climatic changes affect regional conditions and by the actions China takes to mitigate or adapt to climate change impacts. One potential mitigation strategy is to promote soil carbon (C) sequestration, which would improve soil quality while simultaneously contributing to the mitigation of climate change. The IPCC estimates that 40 Pg of C could be sequestered in cropland soils worldwide over the next century. Here we assess the potential for soil C sequestration with conversion of a conventional till (CT) continuous wheat system to a wheat-corn double cropping system and by implementing no till (NT) management for both continuous wheat and wheat-corn systems. To assess the influence of these management changes under a changing climate, we use two climate change scenarios at two time periods in the EPIC agro-ecosystem simulation model. The applied climate change scenarios are from the HadCM3 Global Climate Model for the time periods 2015-2045 and 2070-2099. The HadCM3 model projects that both temperature and precipitation will increase throughout the next century with increases of greater than 5 °C and up to 300 mm possible by 2099. An increase in the variability of temperature is also projected and is, accordingly, applied in the simulations. The EPIC model indicates that winter wheat yields would increase on average by 0.2 Mg ha-1 in the 2030 period and by 0.8 Mg ha-1 in the 2085 period due largely to the warmer nighttime temperatures and higher precipitation projected by the HadCM3 model. Simulated yields were not significantly affected by imposed changes in crop management. Simulated soil organic C content was higher under both NT management and double cropping than under CT continuous wheat. Soil C sequestration rates for continuous wheat systems

  14. Dynamics of soil carbon, nitrogen and soil respiration in farmer’s field with conservation agriculture Siem Reap, Cambodia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The years of intensive tillage in many countries, including Cambodia, have caused significant decline in agriculture’s natural resources that could threaten the future of agricultural production and sustainability worldwide. Long-term tillage system and site-specific crop management can affect chang...

  15. Improving Soil Organic Carbon stock estimates in agricultural topsoil at a regional scale using a Stochastic Gradient Boosting technique

    NASA Astrophysics Data System (ADS)

    Schillaci, Calogero; Lombardo, Luigi; Saia, Sergio; Fantappiè, Maria; Märker, Michael; Acutis, Marco

    2016-04-01

    Agro-ecosystems have a paramount importance as a source of goods and incomes and have a highly unexpressed potential to mitigate greenhouse gasses (GHG) emission. In agro-ecosystems, Soil Organic Carbon (SOC) is recognized as the most important trait to be managed in order to maintain soil fertility and ecosystems services. Accurate laboratory analysis is indeed the best way to investigate soils. However, it is expensive and time consuming when aiming at gaining information on large areas such as an entire district or region. Remote Sensing (RS) is recently offering increasingly detailed Digital Elevation Models (DEMs) and low-cost multispectral satellite imagery. Moreover accurate worldwide climate records of the last 50 years were recently made freely available. Across Sicily, there is a strong heterogeneity of agro-ecosystems, with a dominance of field crops and orchards. In the present work, we modeled the SOC through a wide range of predictors including both ecosystem and agronomic characteristics of the soils, such as panchromatic bands, a Normalized Differenced Vegetation Index NDVI and landuse based on multispectral remote-sensed data LANDSAT ETM+7, terrain attributes derived by radar satellite data from the Shuttle Radar Topographic Mission (SRTM), as well as soil texture information and climate data record from WORLDCLIM. As dependent variable, a set of 2,891 Walkley-Black SOC and 1,049 bulk density laboratory analyses collected throughout Sicily (Italy) was used for modelling the CS stock and build the map. The Stochastic Gradient Treeboost (SGT) learning algorithm was applied to 75% of the CS stock dataset. The remaining 25% was used to validate the model. In addition, the SGT was compared to a Generalized Linear Mixed Model (GLMM). Both SGT and GLMM models show a high performance. With regards to the full model, both algorithms designated temperature and annual rainfall as fundamental predictors of CS. In addition, SGT highlighted the annual rainfall

  16. The biogeochemical footprint of agricultural soil erosion

    NASA Astrophysics Data System (ADS)

    Govers, Gerard; Van Oost, Kristof; Wang, Zhengang

    2015-04-01

    Global biogeochemical cycles are a key component of the functioning of the Earth System: these cycles are all, to a varying extent, disturbed by human activities which not only has dramatic consequences for the global climate but also for the acidity of the world's oceans. It is only relatively recently that the role of lateral fluxes related to surface water movement and soil erosion and deposition (and the way those fluxes are modified by human action) is explicitly considered by the scientific community. In this paper we present an overview of our present-day understanding of the role of agricultural soil erosion in the global cycles of carbon, nitrogen, phosphorous and silica. We discuss the major processes through which erosion affects these global cycles and pay particular attention to the knowledge gaps that prevent us from accurately assessing the impact of soil erosion on global biogeochemical cycling at different temporal scales. Furthering our understanding (and better constraining our estimates) will require progress both in terms of model development and process understanding. Research needs can be most clearly identified with respect to soil organic carbon: (i) at present, large-scale soil erosion (and deposition) models are poorly constrained so that the amount of carbon mobilised by erosion (and its fate) cannot be accurately estimated and (ii) the fate of soil organic carbon buried by deposition or delivered to river network is poorly understood. Uncertainties for N, P and Si are larger than those for C as we have less information on the amount of these elements stored in agricultural soils and/or do not fully understand how these elements cycle through the soil/plant system. Agricultural soil erosion does not affect soil functioning through its effect on biogeochemical cycling. Erosion directly affects soil hydrological functioning and is likely to affect weathering processes and soil production. Addressing all these issues requires the

  17. Potential of temperate agricultural soils for carbon sequestration: A meta-analysis of land-use effects.

    PubMed

    Kämpf, Immo; Hölzel, Norbert; Störrle, Maria; Broll, Gabriele; Kiehl, Kathrin

    2016-10-01

    Restoring depleted soil organic carbon (SOC) stocks of arable land to remove carbon from the atmosphere and offset fossil fuel emissions is a promising strategy for the mitigation of climate change. In agroecosystems conservational tillage practices and the abandonment of formerly plowed fields (ex-arable land) are shown to have the highest potential to sequester SOC. Nevertheless reported sequestration rates vary and the effects of environmental site conditions remain poorly understood. Our results are based on a meta-analysis of 273 paired SOC estimates from 65 publications which included only mineral soils from the temperate zone. SOC stocks of ex-arable grasslands with an average of 14years since abandonment were 18% larger compared to the SOC of arable land. Likewise, SOC stocks of never-plowed grassland plots were 11% larger than the SOC stocks of abandoned fields. The average sequestration rate was 0.72t Cha(-1)yr(-1). Semi-arid and sub-humid climate as well as low initial SOC stocks positively affected proportional SOC gains suggesting that the recovery of carbon stocks is not limited by low primary production. Therefore, the northward shift of cultivation areas in the temperate zone will lead to the abandonment of soils with high SOC recovery potential. However, if native soils are opened up elsewhere to compensate for yield losses due to abandonment the surplus of SOC in ex-arable land can easily be overcompensated by cultivation losses. PMID:27232969

  18. Potential of temperate agricultural soils for carbon sequestration: A meta-analysis of land-use effects.

    PubMed

    Kämpf, Immo; Hölzel, Norbert; Störrle, Maria; Broll, Gabriele; Kiehl, Kathrin

    2016-10-01

    Restoring depleted soil organic carbon (SOC) stocks of arable land to remove carbon from the atmosphere and offset fossil fuel emissions is a promising strategy for the mitigation of climate change. In agroecosystems conservational tillage practices and the abandonment of formerly plowed fields (ex-arable land) are shown to have the highest potential to sequester SOC. Nevertheless reported sequestration rates vary and the effects of environmental site conditions remain poorly understood. Our results are based on a meta-analysis of 273 paired SOC estimates from 65 publications which included only mineral soils from the temperate zone. SOC stocks of ex-arable grasslands with an average of 14years since abandonment were 18% larger compared to the SOC of arable land. Likewise, SOC stocks of never-plowed grassland plots were 11% larger than the SOC stocks of abandoned fields. The average sequestration rate was 0.72t Cha(-1)yr(-1). Semi-arid and sub-humid climate as well as low initial SOC stocks positively affected proportional SOC gains suggesting that the recovery of carbon stocks is not limited by low primary production. Therefore, the northward shift of cultivation areas in the temperate zone will lead to the abandonment of soils with high SOC recovery potential. However, if native soils are opened up elsewhere to compensate for yield losses due to abandonment the surplus of SOC in ex-arable land can easily be overcompensated by cultivation losses.

  19. Soil and soil organic carbon redistribution on the landscape

    NASA Astrophysics Data System (ADS)

    Ritchie, Jerry C.; McCarty, Gregory W.; Venteris, Erik R.; Kaspar, T. C.

    2007-09-01

    Patterns of soil organic carbon (SOC) vary widely across the landscape leading to large uncertainties in the SOC budget especially for agricultural landscapes where water, tillage and wind erosion redistributes soil and SOC across the landscape. It is often assumed that soil erosion results in a loss of SOC from the agricultural ecosystem but recent studies indicate that soil erosion and its subsequent redistribution within fields can stimulate carbon sequestration in agricultural ecosystems. This study investigates the relationship between SOC and soil redistribution patterns on agricultural landscapes. Soil redistribution (erosion and deposition) patterns were estimated in three tilled agricultural fields using the fallout 137Cesium technique. 137Cs and SOC concentrations of upland soils are significantly correlated in our study areas. Upland areas (eroding) have significantly less SOC than soils in deposition areas. SOC decreased as gradient slope increases and soils on concave slopes had higher SOC than soils on convex slopes. These data suggest that soil redistribution patterns and topographic patterns may be used to help understand SOC dynamics on the landscape. Different productivity and oxidation rates of SOC of eroded versus deposited soils also contribute to SOC spatial patterns. However, the strong significant relationships between soil redistribution and SOC concentrations in the upland soil suggest that they are moving along similar physical pathways in these systems. Our study also indicates that geomorphic position is important for understanding soil movement and redistribution patterns within a field or watershed. Such information can help develop or implement management systems to increase SOC in agricultural ecosystems.

  20. Carbon balance of Russian agricultural land

    NASA Astrophysics Data System (ADS)

    Schepaschenko, D.; Shvidenko, A.; Schepaschenko, M.

    2012-04-01

    Russia managed 218.7 mln ha agricultural land (2009) in accordance with national statistics (FSSS, 2011: http://www.gks.ru/dbscripts/Cbsd/DBInet.cgi#1). Among that, 91.75 mln ha is arable land; 92.05 mln ha - hayfield and pasture; 34.9 mln ha - abandoned arable and fallow. Abandoned arable area is not indicated directly in the statistics, but can be calculated as a difference between "arable" and "cultivated" area. We estimated carbon balance of agricultural land by accounting carbon fluxes. Carbon sink includes: net primary productivity (NPP), applying fertilizes and liming. Carbon losses include soil respiration (SR), harvest and lateral flux. The initial data (cultivated area and harvest distribution by regions and crop) was derived from national agriculture statistics (FSSS, 2011). NPP was estimated via harvest and set of regression models. Average NPP for agricultural land was estimated at 435 g C m-2 (530 g C m-2 for crops). Soil respiration was calculated by a model (Mukhortova et. al., 1011: http://www.iiasa.ac.at/Research/FOR/forest_cdrom/Articles/Mukhortova_2011_IBFRA_SR.pdf) developed for Russia which is based on all available empirical data and accounted for climatic parameters, soil type and management practice. Average SR of agricultural land is 344 g C m-2 (372 g C m-2 for the cropland). We applied the IPCC method (National inventory, 2010; IPCC, 2006) for fertilizer and lateral fluxes assessment. The total carbon balance of agricultural land is almost in equilibrium (-0.04 t C ha-1) in spite of arable land is a carbon source (-0.84 t C ha-1). The highest sink (1.21 t C ha-1) is provided by abandoned land. Carbon fluxes vary substantially depending on seasonal weather conditions. For example grains' NPP in 2010 (dry and hot summer in major agricultural regions of European Russia) was estimated at 32% less compare to 2009 and the total carbon balance of this land category decreased by order of magnitude. We used Russian land cover (Schepaschenko et al

  1. The cost effectiveness of a policy to store carbon in Australian agricultural soils to abate greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    White, Robert E.; Davidson, Brian

    2015-07-01

    Data for cropping and pastoral enterprises in south eastern Australia were used in a cost-effectiveness analysis to assess the feasibility of abating greenhouse gas (GHG) emissions through storing soil carbon (C) as soil organic matter under the Australian government's Carbon Farming Initiative. We used the C credit value for 2013-14 of 24.15 per tonne of CO2- equivalent (CO2-e) and a C storage rate of 0.5 tonne C/hectare/year for conversion of cropland to pasture. Given that a change of enterprise is driven primarily by farmer returns, we found that none of the changes were feasible at current prices, with the exception of wheat to cattle or sheep in an irrigated system, and dryland cotton to cattle or sheep. Given that our model scenario assumed the most favourable economic factors, it is unlikely that increased soil C storage through a change from cropping to pasture can make a significant contribution to abating Australia's CO2 emissions. However, of greater concern to society is the methane emissions from grazing cattle or sheep, which would negate any gain in soil C under pasture, except for a switch from dryland cropping to sheep.

  2. Soil organic carbon dynamics and non-CO2 gas fluxes from agricultural soils under organic and non-organic management - results of two meta-studies

    NASA Astrophysics Data System (ADS)

    Gattinger, Andreas; Skinner, Colin; Müller, Adrian; Mäder, Paul; Niggli, Urs

    2015-04-01

    It is anticipated that organic farming systems provide benefits concerning soil conservation and climate protection. Therefore, meta-studies on soil organic carbon (SOC) and soil-derived greenhouse (GHG) fluxes, respectively, were conducted to proof this assumption. Datasets from 74 studies from pair wise comparisons of organic versus non-organic farming systems were subjected to meta-analysis to identify differences in soil organic carbon (SOC). We found significant differences and higher values for organically farmed soils of 0.18±0.06 % points (mean±95% confidence interval) for SOC concentrations, 3.50±1.08 Mg C ha-1 for stocks, and 0.45±0.21 Mg C ha-1 a-1 for sequestration rates compared to non-organic management. Meta-regression did not deliver clear results on drivers, but differences in external C inputs and crop rotations seemed important. Restricting the analysis to zero net input organic systems, i.e. without nutrient inputs from outside the system, and retaining only the datasets with highest data quality (measured soil bulk densities and external C and N inputs), the mean difference in SOC stocks between the farming systems was still significant (1.98±1.50 Mg C ha-1), while the difference in sequestration rates became insignificant (0.07±0.08 Mg C ha-1 a-1). The SOC dataset mainly covers top soil and temperate zones, while only few data from tropical regions and sub soil horizons exist. For the second meta-study measured soil-derived nitrous oxide and methane flux data from soils under organic and non-organic management from 19 farming system comparisons were analysed. Based on 12 studies that cover annual measurements, it appeared with a high significance that area-scaled nitrous oxide emissions from organically managed soils are 492±160 kg CO2 eq. ha-1 a-1 lower than from non-organically managed soils. For arable soils the difference amounts to 497±162 kg CO2 eq. ha-1 a-1. However, yield-scaled nitrous oxide emissions are higher by 41±34 kg

  3. [Research methods of carbon sequestration by soil aggregates: a review].

    PubMed

    Chen, Xiao-Xia; Liang, Ai-Zhen; Zhang, Xiao-Ping

    2012-07-01

    To increase soil organic carbon content is critical for maintaining soil fertility and agricultural sustainable development and for mitigating increased greenhouse gases and the effects of global climate change. Soil aggregates are the main components of soil, and have significant effects on soil physical and chemical properties. The physical protection of soil organic carbon by soil aggregates is the important mechanism of soil carbon sequestration. This paper reviewed the organic carbon sequestration by soil aggregates, and introduced the classic and current methods in studying the mechanisms of carbon sequestration by soil aggregates. The main problems and further research trends in this study field were also discussed.

  4. Evidence for carbon sequestration by agricultural liming

    NASA Astrophysics Data System (ADS)

    Hamilton, Stephen K.; Kurzman, Amanda L.; Arango, Clay; Jin, Lixin; Robertson, G. Philip

    2007-06-01

    Agricultural lime can be a source or a sink for CO2, depending on whether reaction occurs with strong acids or carbonic acid. Here we examine the impact of liming on global warming potential by comparing the sum of Ca2+ and Mg2+ to carbonate alkalinity in soil solutions beneath unmanaged vegetation versus limed row crops, and of streams and rivers in agricultural versus forested watersheds, mainly in southern Michigan. Soil solutions sampled by tension indicated that lime can act as either a source or a sink for CO2. However, infiltrating waters tended to indicate net CO2 uptake, as did tile drainage waters and streams draining agricultural watersheds. As nitrate concentrations increased in infiltrating waters, lime switched from a net CO2 sink to a source, implying nitrification as a major acidifying process. Dissolution of lime may sequester CO2 equal to roughly 25-50% of its C content, in contrast to the prevailing assumption that all of the carbon in lime becomes CO2. The ˜30 Tg/yr of agricultural lime applied in the United States could thus sequester up to 1.9 Tg C/yr, about 15% of the annual change in the U.S. CO2 emissions (12 Tg C/yr for 2002-2003). The implications of liming for atmospheric CO2 stabilization should be considered in strategies to mitigate global climate change.

  5. Integrating depth functions and hyper-scale terrain analysis for 3D soil organic carbon modeling in agricultural fields at regional scale

    NASA Astrophysics Data System (ADS)

    Ramirez-Lopez, L.; van Wesemael, B.; Stevens, A.; Doetterl, S.; Van Oost, K.; Behrens, T.; Schmidt, K.

    2012-04-01

    Soil Organic Carbon (SOC) represents a key component in the global C cycle and has an important influence on the global CO2 fluxes between terrestrial biosphere and atmosphere. In the context of agricultural landscapes, SOC inventories are important since soil management practices have a strong influence on CO2 fluxes and SOC stocks. However, there is lack of accurate and cost-effective methods for producing high spatial resolution of SOC information. In this respect, our work is focused on the development of a three dimensional modeling approach for SOC monitoring in agricultural fields. The study area comprises ~420 km2 and includes 4 of the 5 agro-geological regions of the Grand-Duchy of Luxembourg. The soil dataset consist of 172 profiles (1033 samples) which were not sampled specifically for this study. This dataset is a combination of profile samples collected in previous soil surveys and soil profiles sampled for other research purposes. The proposed strategy comprises two main steps. In the first step the SOC distribution within each profile (vertical distribution) is modeled. Depth functions for are fitted in order to summarize the information content in the profile. By using these functions the SOC can be interpolated at any depth within the profiles. The second step involves the use of contextual terrain (ConMap) features (Behrens et al., 2010). These features are based on the differences in elevation between a given point location in the landscape and its circular neighbourhoods at a given set of different radius. One of the main advantages of this approach is that it allows the integration of several spatial scales (eg. local and regional) for soil spatial analysis. In this work the ConMap features are derived from a digital elevation model of the area and are used as predictors for spatial modeling of the parameters of the depth functions fitted in the previous step. In this poster we present some preliminary results in which we analyze: i. The use of

  6. Erosion of soil organic carbon: implications for carbon sequestration

    USGS Publications Warehouse

    Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.; McPherson, B.J.; Sundquist, E.T.

    2009-01-01

    Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

  7. Soil carbon dynamics

    NASA Astrophysics Data System (ADS)

    Trumbore, Susan; Barbosa de Camargo, Plínio

    The amount of organic carbon (C) stored in the upper meter of mineral soils in the Amazon Basin (˜40 Pg C) represents ˜3% of the estimated global store of soil carbon. Adding surface detrital C stocks and soil carbon deeper than 1 m can as much as quadruple this estimate. The potential for Amazon soil carbon to respond to changes in land use, climate, or atmospheric composition depends on the form and dynamics of soil carbon. Much (˜30% in the top ˜10 cm but >85% in soils to 1 m depth) of the carbon in mineral soils of the Oxisols and Ultisols that are the predominant soil types in the Amazon Basin is in forms that are strongly stabilized, with mean ages of centuries to thousands of years. Measurable changes in soil C stocks that accompany land use/land cover change occur in the upper meter of soil, although the presence of deep roots in forests systems drives an active C cycle at depths >1 m. Credible estimates of the potential for changes in Amazon soil C stocks with future land use and climate change are much smaller than predictions of aboveground biomass change. Soil organic matter influences fertility and other key soil properties, and thus is important independent of its role in the global C cycle. Most work on C dynamics is limited to upland soils, and more is needed to investigate C dynamics in poorly drained soils. Work is also needed to relate cycles of C with water, N, P, and other elements.

  8. Soil carbon determination by thermogravimetrics.

    PubMed

    Pallasser, Robert; Minasny, Budiman; McBratney, Alex B

    2013-01-01

    Determination of soil constituents and structure has a vital role in agriculture generally. Methods for the determination of soil carbon have in particular gained greater currency in recent times because of the potential that soils offer in providing offsets for greenhouse gas (CO2-equivalent) emissions. Ideally, soil carbon which can also be quite diverse in its makeup and origin, should be measureable by readily accessible, affordable and reliable means. Loss-on-ignition is still a widely used method being suitably simple and available but may have limitations for soil C monitoring. How can these limitations be better defined and understood where such a method is required to detect relatively small changes during soil-C building? Thermogravimetric (TGA) instrumentation to measure carbonaceous components has become more interesting because of its potential to separate carbon and other components using very precise and variable heating programs. TGA related studies were undertaken to assist our understanding in the quantification of soil carbon when using methods such as loss-on-ignition. Combining instrumentation so that mass changes can be monitored by mass spectrometer ion currents has elucidated otherwise hidden features of thermal methods enabling the interpretation and evaluation of mass-loss patterns. Soil thermogravimetric work has indicated that loss-on-ignition methods are best constrained to temperatures from 200 to 430 °C for reliable determination for soil organic carbon especially where clay content is higher. In the absence of C-specific detection where mass only changes are relied upon, exceeding this temperature incurs increasing contributions from inorganic sources adding to mass losses with diminishing contributions related to organic matter. The smaller amounts of probably more recalcitrant organic matter released at the higher temperatures may represent mineral associated material and/or simply more refractory forms.

  9. Impact of agricultural management on bacterial laccase-encoding genes with possible implications for soil carbon storage in semi-arid Mediterranean olive farming

    PubMed Central

    Moreno, Beatriz

    2016-01-01

    Background: In this work, we aimed to gain insights into the contribution of soil bacteria to carbon sequestration in Mediterranean habitats. In particular, we aimed to use bacterial laccase-encoding genes as molecular markers for soil organic C cycling. Using rainfed olive farming as an experimental model, we determined the stability and accumulation levels of humic substances and applied these data to bacterial laccase-encoding gene expression and diversity in soils under four different agricultural management systems (bare soils under tillage/no tillage and vegetation cover under chemical/mechanical management). Materials and Methods: Humic C (> 104 Da) was subjected to isoelectric focusing. The GC-MS method was used to analyze aromatic hydrocarbons. Real-Time PCR quantification and denaturing gradient gel electrophoresis (DGGE) for functional bacterial laccase-like multicopper oxidase (LMCO)-encoding genes and transcripts were also carried out. Results: Soils under spontaneous vegetation, eliminated in springtime using mechanical methods for more than 30 years, showed the highest humic acid levels as well as the largest bacterial population rich in laccase genes and transcripts. The structure of the bacterial community based on LMCO genes also pointed to phylogenetic differences between these soils due to the impact of different management systems. Soils where herbicides were used to eliminate spontaneous vegetation once a year and those where pre-emergence herbicides resulted in bare soils clustered together for DNA-based DGGE analysis, which indicated a certain amount of microbial selection due to the application of herbicides. When LMCO-encoding gene expression was studied, soils where cover vegetation was managed either with herbicides or with mechanical methods showed less than 10% similarity, suggesting that the type of weed management strategy used can impact weed community composition and consequently laccase substrates derived from vegetation decay

  10. Soil Carbon Sequestration: Perspectives from Australia

    NASA Astrophysics Data System (ADS)

    Sanderman, J.; Macdonald, L.; Baldock, J.

    2011-12-01

    Australia is currently embarking upon an unparalleled program to mitigate greenhouse gas emissions by engaging farmers and landholders to reduce emissions and store carbon in the soil. Currently, the magnitude of a potential soil carbon sink in Australian agricultural soils is largely unknown. The oft repeated rubric that adoption of recommended management practices (RMP) can raise soil carbon levels to 50-66% of pre-clearing levels has lead many to conclude that soil carbon sequestration can offset a large portion of Australia's current greenhouse gas emissions. Is there evidence in Australia (and abroad) to support these sequestration rates? In this presentation, we will present findings from both a retrospective analysis of existing field trial data and preliminary results from a national scale assessment of current soil carbon stocks under different agricultural management practices. A comprehensive review of field-trial data in Australia suggests that most management shifts within a given agricultural system (i.e. tillage, stubble management, fertilizer application, etc...) result in modest relative gains of 0.1 to 0.3 tC ha-1 yr-1. Importantly, whenever time series data was available, we found that the relative improvement in soil carbon stocks under RMPs was due to a reduction in the rate of loss of soil carbon and not in an actual increase in soil carbon. This finding has important repercussions for both how we think about soil carbon sequestration and how we can account for it in an accounting framework. Current research within the National Soil Carbon Research Program looks to assess the potential for agricultural management to influence soil carbon content and its distribution within various measurable carbon pools (particulate, humus, charcoal-like). For example, 200 randomly selected farms have been sampled in two major agricultural regions in South Australia based on a soil-type by rainfall stratification. In addition to measuring carbon content and

  11. Inherent agricultural constraints in Allegheny Plateau soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    World population increases demand increased agricultural production. This can be accomplished through improved cultivars and production techniques or increased use of previously marginal agricultural regions. In the Allegheny Plateau (AP) region of the Appalachian Mountains, acid soils with toxic ...

  12. Carbon Nanomaterials in Agriculture: A Critical Review

    PubMed Central

    Mukherjee, Arnab; Majumdar, Sanghamitra; Servin, Alia D.; Pagano, Luca; Dhankher, Om Parkash; White, Jason C.

    2016-01-01

    There has been great interest in the use of carbon nano-materials (CNMs) in agriculture. However, the existing literature reveals mixed effects from CNM exposure on plants, ranging from enhanced crop yield to acute cytotoxicity and genetic alteration. These seemingly inconsistent research-outcomes, taken with the current technological limitations for in situ CNM detection, present significant hurdles to the wide scale use of CNMs in agriculture. The objective of this review is to evaluate the current literature, including studies with both positive and negative effects of different CNMs (e.g., carbon nano-tubes, fullerenes, carbon nanoparticles, and carbon nano-horns, among others) on terrestrial plants and associated soil-dwelling microbes. The effects of CNMs on the uptake of various co-contaminants will also be discussed. Last, we highlight critical knowledge gaps, including the need for more soil-based investigations under environmentally relevant conditions. In addition, efforts need to be focused on better understanding of the underlying mechanism of CNM-plant interactions. PMID:26941751

  13. Assessment on the rates and potentials of soil organic carbon sequestration in agricultural lands in Japan using a process-based model and spatially explicit land-use change inventories - Part 2: Future potentials

    NASA Astrophysics Data System (ADS)

    Yagasaki, Y.; Shirato, Y.

    2014-08-01

    Future potentials of the sequestration of soil organic carbon (SOC) in agricultural lands in Japan were estimated using a simulation system we recently developed to simulate SOC stock change at country-scale under varying land-use change, climate, soil, and agricultural practices, in a spatially explicit manner. Simulation was run from 1970 to 2006 with historical inventories, and subsequently to 2020 with future scenarios of agricultural activity comprised of various agricultural policy targets advocated by the Japanese government. Furthermore, the simulation was run subsequently until 2100 while forcing no temporal changes in land-use and agricultural activity to investigate duration and course of SOC stock change at country scale. A scenario with an increased rate of organic carbon input to agricultural fields by intensified crop rotation in combination with the suppression of conversion of agricultural lands to other land-use types was found to have a greater reduction of CO2 emission by enhanced soil carbon sequestration, but only under a circumstance in which the converted agricultural lands will become settlements that were considered to have a relatively lower rate of organic carbon input. The size of relative reduction of CO2 emission in this scenario was comparable to that in another contrasting scenario (business-as-usual scenario of agricultural activity) in which a relatively lower rate of organic matter input to agricultural fields was assumed in combination with an increased rate of conversion of the agricultural fields to unmanaged grasslands through abandonment. Our simulation experiment clearly demonstrated that net-net-based accounting on SOC stock change, defined as the differences between the emissions and removals during the commitment period and the emissions and removals during a previous period (base year or base period of Kyoto Protocol), can be largely influenced by variations in future climate. Whereas baseline-based accounting, defined

  14. CQESTR Simulations of soil organic carbon dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A processed-based carbon (C) model, CQESTR (sequester), was used to predict soil organic carbon (SOC) dynamics and examine the effect of agricultural management practices on SOC accretion in three diverse regions of the USA. The three regions chosen had long-term experiments (LTEs) ranging from 23 t...

  15. Carbon Sequestration in Forest Soils

    NASA Astrophysics Data System (ADS)

    Lal, R.

    2006-05-01

    Carbon (C) sequestration in soils and forests is an important strategy of reducing the net increase in atmospheric CO2 concentration by fossil fuel combustion, deforestation, biomass burning, soil cultivation and accelerated erosion. Further, the so-called "missing or fugitive CO2" is also probably being absorbed in a terrestrial sink. Three of the 15 strategies proposed to stabilize atmospheric CO2 concentrations by 2054, with each one to sequester 1 Pg Cyr-1, include: (i) biofuel plantations for bioethanol production, (ii) reforestation, afforestation and establishment of new plantations, and (iii) conversion of plow tillage to no-till farming. Enhancing soil organic carbon (SOC) pool is an important component in each of these three options, but especially so in conversion of degraded/marginal agricultural soils to short rotation woody perennials, and establishment of plantations for biofuel, fiber and timber production. Depending upon the prior SOC loss because of the historic land used and management-induced soil degradation, the rate of soil C sequestration in forest soils may be 0 to 3 Mg C ha-1 yr-1. Tropical forest ecosystems cover 1.8 billion hectares and have a SOC sequestration potential of 200 to 500 Tg C yr-1 over 59 years. However, increasing production of forest biomass may not always increase the SOC pool. Factors limiting the rate of SOC sequestration include C: N ratio, soil availability of N and other essential nutrients, concentration of recalcitrant macro-molecules (e.g., lignin, suberin), soil properties (e.g., clay content and mineralogy, aggregation), soil drainage, and climate (mean annual precipitation and temperature). The SOC pool can be enhanced by adopting recommended methods of forest harvesting and site preparation to minimize the "Covington effect," improving soil drainage, alleviating soil compaction, growing species with a high NPP, and improving soil fertility including the availability of micro-nutrients. Soil fertility

  16. How does soil management affect carbon losses from soils?

    NASA Astrophysics Data System (ADS)

    Klik, A.; Trümper, G.

    2009-04-01

    Agricultural soils are a major source as well as a sink of organic carbon (OC). Amount and distribution of OC within the soil and within the landscape are driven by land management but also by erosion and deposition processes. At the other hand the type of soil management influences mineralization and atmospheric carbon dioxide losses by soil respiration. In a long-term field experiment the impacts of soil tillage systems on soil erosion processes were investigated. Following treatments were compared: 1) conventional tillage (CT), 2) conservation tillage with cover crop during the winter period (CS), and 3) no-till with cover crop during winter period (NT). The studies were carried out at three sites in the Eastern part of Austria with annual precipitation amounts from 650 to 900 mm. The soil texture ranged from silt loam to loam. Since 2007 soil CO2 emissions are measured with a portable soil respiration system in intervals of about one week, but also in relation to management events. Concurrent soil temperature and soil water content are measured and soil samples are taken for chemical and microbiological analyses. An overall 14-yr. average soil loss between 1.0 t.ha-1.yr-1 for NT and 6.1 t.ha-1.yr-1 for CT resulted in on-site OC losses from 18 to 79 kg ha-1.yr-1. The measurements of the carbon dioxide emissions from the different treatments indicate a high spatial variation even within one plot. Referred to CT plots calculated carbon losses amounted to 65-94% for NT plots while for the different RT plots they ranged between 84 and 128%. Nevertheless site specific considerations have to be taken into account. Preliminary results show that the adaptation of reduced or no-till management strategies has enormous potential in reducing organic carbon losses from agricultural used soils.

  17. A short-term assessment of carbon dioxide fluxes under contrasting agricultural and soil management practices in Zimbabwe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two of the biggest problems facing humankind are feeding an exponentially growing human population and preventing the negative effects of climate change from record concentrations of atmospheric greenhouse gases (GHGs). Agriculture could address both of these problems. For example, tillage and cover...

  18. Geogenic and agricultural controls on the geochemical composition of European agricultural soils

    NASA Astrophysics Data System (ADS)

    Mol, Gerben; Saaltink, Remon; Griffioen, Jasper; Birke, Manfred

    2014-05-01

    Purpose: Concern about the environmental impact of agriculture caused by intensification is growing as large amounts of nutrients and contaminants are introduced into the environment. The aim of this paper is to identify the geogenic and agricultural controls on the elemental composition of European, grazing and agricultural soils. Materials and methods: Robust factor analysis was applied to data series for Al,B,Ca, Cd,Co, Cu, Fe, K, Mg,Mn, Na,Ni, P, S, Se, Sr, U, Zn (ICP-MS) and SiO2, K2O, Na2O, Fe2O3, Al2O3 (XRF) based on the European GEMAS dataset. In addition, the following general soil properties were included: clay content, pH, chemical index of alteration (CIA), loss on ignition (LOI), cation exchange capacity (CEC), total organic carbon (TOC) and total carbon and total sulfur. Furthermore, this dataset was coupled to a dataset containing information of historic P2O5 fertilization across Europe. Also, a mass balance was carried out for Cd, Cu and Zn to determine if concentrations of these elements found in the soils have their origin in historic P2O5 fertilization. Results and discussion: Seven geogenic factors and one agricultural factor were found of which four prominent ones (all geogenic): chemical weathering, reactive iron-aluminum oxide minerals, clay minerals and carbonate minerals. Results for grazing and agricultural soils were near identical, which further proofs the prominence of geogenic controls on the total elemental composition. When the cumulative amount of P2O5 fertilization was considered, no extra agriculture-related factors became visible. The mass balance confirms these observations. Conclusion: Overall, the geological controls are more important for the total soil chemistry in agricultural and grazing land soils than the anthropogenic controls.

  19. Intensive agriculture reduces soil biodiversity across Europe.

    PubMed

    Tsiafouli, Maria A; Thébault, Elisa; Sgardelis, Stefanos P; de Ruiter, Peter C; van der Putten, Wim H; Birkhofer, Klaus; Hemerik, Lia; de Vries, Franciska T; Bardgett, Richard D; Brady, Mark Vincent; Bjornlund, Lisa; Jørgensen, Helene Bracht; Christensen, Sören; Hertefeldt, Tina D'; Hotes, Stefan; Gera Hol, W H; Frouz, Jan; Liiri, Mira; Mortimer, Simon R; Setälä, Heikki; Tzanopoulos, Joseph; Uteseny, Karoline; Pižl, Václav; Stary, Josef; Wolters, Volkmar; Hedlund, Katarina

    2015-02-01

    Soil biodiversity plays a key role in regulating the processes that underpin the delivery of ecosystem goods and services in terrestrial ecosystems. Agricultural intensification is known to change the diversity of individual groups of soil biota, but less is known about how intensification affects biodiversity of the soil food web as a whole, and whether or not these effects may be generalized across regions. We examined biodiversity in soil food webs from grasslands, extensive, and intensive rotations in four agricultural regions across Europe: in Sweden, the UK, the Czech Republic and Greece. Effects of land-use intensity were quantified based on structure and diversity among functional groups in the soil food web, as well as on community-weighted mean body mass of soil fauna. We also elucidate land-use intensity effects on diversity of taxonomic units within taxonomic groups of soil fauna. We found that between regions soil food web diversity measures were variable, but that increasing land-use intensity caused highly consistent responses. In particular, land-use intensification reduced the complexity in the soil food webs, as well as the community-weighted mean body mass of soil fauna. In all regions across Europe, species richness of earthworms, Collembolans, and oribatid mites was negatively affected by increased land-use intensity. The taxonomic distinctness, which is a measure of taxonomic relatedness of species in a community that is independent of species richness, was also reduced by land-use intensification. We conclude that intensive agriculture reduces soil biodiversity, making soil food webs less diverse and composed of smaller bodied organisms. Land-use intensification results in fewer functional groups of soil biota with fewer and taxonomically more closely related species. We discuss how these changes in soil biodiversity due to land-use intensification may threaten the functioning of soil in agricultural production systems.

  20. Anthropogenic perturbation of the global carbon cycle as a result of agricultural carbon erosion and burial

    NASA Astrophysics Data System (ADS)

    Wang, Zhengang; Govers, Gerard; Kaplan, Jed; Hoffmann, Thomas; Doetterl, Sebastian; Six, Johan; Van Oost, Kristof

    2016-04-01

    Changes in terrestrial carbon storage exert a strong control over atmospheric CO2 concentrations but the underlying mechanisms are not fully constrained. Anthropogenic land cover change is considered to represent an important carbon loss mechanism, but current assessments do not consider the associated acceleration of carbon erosion and burial in sediments. We evaluated the role of anthropogenic soil erosion and the resulting carbon fluxes between land and atmosphere from the onset of agriculture to the present day. We show, here, that agricultural erosion induced a significant cumulative net uptake of 198±57 Pg carbon on terrestrial ecosystems. This erosion-induced soil carbon sink is estimated to have offset 74±21% of carbon emissions. Since 1850, erosion fluxes have increased 3-fold. As a result, the erosion and lateral transfer of organic carbon in relation to human activities is an important driver of the global carbon cycle at millennial timescales.

  1. Evaluating Soil Carbon Sequestration in Central Iowa

    NASA Astrophysics Data System (ADS)

    Doraiswamy, P. C.; Hunt, E. R.; McCarty, G. W.; Daughtry, C. S.; Izaurralde, C.

    2005-12-01

    The potential for reducing atmospheric carbon dioxide (CO2) concentration through landuse and management of agricultural systems is of great interest worldwide. Agricultural soils can be a source of CO2 when not properly managed but can also be a sink for sequestering CO2 through proper soil and crop management. The EPIC-CENTURY biogeochemical model was used to simulate the baseline level of soil carbon from soil survey data and project changes in soil organic carbon (SOC) under different tillage and crop management practices for corn and soybean crops. The study was conducted in central Iowa (50 km x 100 km) to simulate changes in soil carbon over the next 50 years. The simulations were conducted in two phases; initially a 25-year period (1971-1995) was simulated using conventional tillage practices since there was a transition in new management after 1995. In the second 25-year period (1996-2020), four different modeling scenarios were applied namely; conventional tillage, mulch tillage, no-tillage and no-tillage with a rye cover crop over the winter. The model simulation results showed potential gains in soil carbon in the top layers of the soil for conservation tillage. The simulations were made at a spatial resolution of 1.6 km x 1.6 km and mapped for the study area. There was a mean reduction in soil organic carbon of 0.095 T/ha per year over the 25-year period starting with 1996 for the conventional tillage practice. However, for management practices of mulch tillage, no tillage and no tillage with cover crop there was an increase in soil organic carbon of 0.12, 0.202 and 0.263 T/ha respectively over the same 25-year period. These results are in general similar to studies conducted in this region.

  2. Uncertainty in soil carbon accounting due to unrecognized soil erosion.

    PubMed

    Sanderman, Jonathan; Chappell, Adrian

    2013-01-01

    The movement of soil organic carbon (SOC) during erosion and deposition events represents a major perturbation to the terrestrial carbon cycle. Despite the recognized impact soil redistribution can have on the carbon cycle, few major carbon accounting models currently allow for soil mass flux. Here, we modified a commonly used SOC model to include a soil redistribution term and then applied it to scenarios which explore the implications of unrecognized erosion and deposition for SOC accounting. We show that models that assume a static landscape may be calibrated incorrectly as erosion of SOC is hidden within the decay constants. This implicit inclusion of erosion then limits the predictive capacity of these models when applied to sites with different soil redistribution histories. Decay constants were found to be 15-50% slower when an erosion rate of 15 t soil ha(-1)  yr(-1) was explicitly included in the SOC model calibration. Static models cannot account for SOC change resulting from agricultural management practices focused on reducing erosion rates. Without accounting for soil redistribution, a soil sampling scheme which uses a fixed depth to support model development can create large errors in actual and relative changes in SOC stocks. When modest levels of erosion were ignored, the combined uncertainty in carbon sequestration rates was 0.3-1.0 t CO2  ha(-1)  yr(-1) . This range is similar to expected sequestration rates for many management options aimed at increasing SOC levels. It is evident from these analyses that explicit recognition of soil redistribution is critical to the success of a carbon monitoring or trading scheme which seeks to credit agricultural activities.

  3. Biochar has no effect on soil respiration across Chinese agricultural soils.

    PubMed

    Liu, Xiaoyu; Zheng, Jufeng; Zhang, Dengxiao; Cheng, Kun; Zhou, Huimin; Zhang, Afeng; Li, Lianqing; Joseph, Stephen; Smith, Pete; Crowley, David; Kuzyakov, Yakov; Pan, Genxing

    2016-06-01

    Biochar addition to soil has been widely accepted as an option to enhance soil carbon sequestration by introducing recalcitrant organic matter. However, it remains unclear whether biochar will negate the net carbon accumulation by increasing carbon loss through CO2 efflux from soil (soil respiration). The objectives of this study were to address: 1) whether biochar addition increases soil respiration; and whether biochar application rate and biochar type (feedstock and pyrolyzing system) affect soil respiration. Two series of field experiments were carried out at 8 sites representing the main crop production areas in China. In experiment 1, a single type of wheat straw biochar was amended at rates of 0, 20 and 40 tha(-1) in four rice paddies and three dry croplands. In experiment 2, four types of biochar (varying in feedstock and pyrolyzing system) were amended at rates of 0 and 20 tha(-1) in a rice paddy under rice-wheat rotation. Results showed that biochar addition had no effect on CO2 efflux from soils consistently across sites, although it increased topsoil organic carbon stock by 38% on average. Meanwhile, CO2 efflux from soils amended with 40 t of biochar did not significantly higher than soils amended with 20 t of biochar. While the biochars used in Experiment 2 had different carbon pools and physico-chemical properties, they had no effect on soil CO2 efflux. The soil CO2 efflux following biochar addition could be hardly explained by the changes in soil physic-chemical properties and in soil microbial biomass. Thus, we argue that biochar will not negate the net carbon accumulation by increasing carbon loss through CO2 efflux in agricultural soils. PMID:26950640

  4. Biochar has no effect on soil respiration across Chinese agricultural soils.

    PubMed

    Liu, Xiaoyu; Zheng, Jufeng; Zhang, Dengxiao; Cheng, Kun; Zhou, Huimin; Zhang, Afeng; Li, Lianqing; Joseph, Stephen; Smith, Pete; Crowley, David; Kuzyakov, Yakov; Pan, Genxing

    2016-06-01

    Biochar addition to soil has been widely accepted as an option to enhance soil carbon sequestration by introducing recalcitrant organic matter. However, it remains unclear whether biochar will negate the net carbon accumulation by increasing carbon loss through CO2 efflux from soil (soil respiration). The objectives of this study were to address: 1) whether biochar addition increases soil respiration; and whether biochar application rate and biochar type (feedstock and pyrolyzing system) affect soil respiration. Two series of field experiments were carried out at 8 sites representing the main crop production areas in China. In experiment 1, a single type of wheat straw biochar was amended at rates of 0, 20 and 40 tha(-1) in four rice paddies and three dry croplands. In experiment 2, four types of biochar (varying in feedstock and pyrolyzing system) were amended at rates of 0 and 20 tha(-1) in a rice paddy under rice-wheat rotation. Results showed that biochar addition had no effect on CO2 efflux from soils consistently across sites, although it increased topsoil organic carbon stock by 38% on average. Meanwhile, CO2 efflux from soils amended with 40 t of biochar did not significantly higher than soils amended with 20 t of biochar. While the biochars used in Experiment 2 had different carbon pools and physico-chemical properties, they had no effect on soil CO2 efflux. The soil CO2 efflux following biochar addition could be hardly explained by the changes in soil physic-chemical properties and in soil microbial biomass. Thus, we argue that biochar will not negate the net carbon accumulation by increasing carbon loss through CO2 efflux in agricultural soils.

  5. Austrian Carbon Calculator (ACC) - modelling soil carbon dynamics in Austrian soils

    NASA Astrophysics Data System (ADS)

    Sedy, Katrin; Freudenschuss, Alexandra; Zethner, Gehard; Spiegel, Heide; Franko, Uwe; Gründling, Ralf; Xaver Hölzl, Franz; Preinstorfer, Claudia; Haslmayr, Hans Peter; Formayer, Herbert

    2014-05-01

    Austrian Carbon Calculator (ACC) - modelling soil carbon dynamics in Austrian soils. The project funded by the Klima- und Energiefonds, Austrian Climate Research Programme, 4th call Authors: Katrin Sedy, Alexandra Freudenschuss, Gerhard Zethner (Environment Agency Austria), Heide Spiegel (Austrian Agency for Health and Food Safety), Uwe Franko, Ralf Gründling (Helmholtz Centre for Environmental Research) Climate change will affect plant productivity due to weather extremes. However, adverse effects could be diminished and satisfying production levels may be maintained with proper soil conditions. To sustain and optimize the potential of agricultural land for plant productivity it will be necessary to focus on preserving and increasing soil organic carbon (SOC). Carbon sequestration in agricultural soils is strongly influenced by management practice. The present management is affected by management practices that tend to speed up carbon loss. Crop rotation, soil cultivation and the management of crop residues are very important measures to influence carbon dynamics and soil fertility. For the future it will be crucial to focus on practical measures to optimize SOC and to improve soil structure. To predict SOC turnover the existing humus balance model the application of the "Carbon Candy Balance" was verified by results from Austrian long term field experiments and field data of selected farms. Thus the main aim of the project is to generate a carbon balancing tool box that can be applied in different agricultural production regions to assess humus dynamics due to agricultural management practices. The toolbox will allow the selection of specific regional input parameters for calculating the C-balance at field level. However farmers or other interested user can also apply their own field data to receive the result of C-dynamics under certain management practises within the next 100 years. At regional level the impact of predefined changes in agricultural management

  6. Assessing different agricultural managements with the use of soil quality indices in a Mediteranean calcareous soil

    NASA Astrophysics Data System (ADS)

    Morugán-Coronado, Alicia; García-Orenes, Fuensanta; Mataix-Solera, Jorge; Arcenegui, Vicky; Cerdà, Artemi

    2013-04-01

    Soil erosion is a major problem in the Mediterranean region due to the arid conditions and torrential rainfalls, which contribute to the degradation of agricultural land. New strategies must be developed to reduce soil losses and recover or maintain soil functionality in order to achieve a sustainable agriculture. An experiment was designed to evaluate the effect of different agricultural management on soil properties and soil quality. Ten different treatments (contact herbicide, systemic herbicide, ploughing, Oat mulch non-plough, Oats mulch plough, leguminous plant, straw rice mulch, chipped pruned branches, residual-herbicide and agro geo-textile, and three control plots including no tillage or control and long agricultural abandonment (shrub on marls and shrub on limestone) were established in 'El Teularet experimental station' located in the Sierra de Enguera (Valencia, Spain). The soil is a Typic Xerorthent developed over Cretaceous marls in an old agricultural terrace. The agricultural management can modify the soil equilibrium and affect its quality. In this work two soil quality indices (models) developed by Zornoza et al. (2007) are used to evaluate the effects of the different agricultural management along 4 years. The models were developed studying different soil properties in undisturbed forest soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. Model 1, that explained 92% of the variance in soil organic carbon (SOC) showed that the SOC can be calculated by the linear combination of 6 physical, chemical and biochemical properties (acid phosphatase, water holding capacity (WHC), electrical conductivity (EC), available phosphorus (P), cation exchange capacity (CEC) and aggregate stability (AS). Model 2 explains 89% of the SOC variance, which can be calculated by means of 7 chemical and biochemical properties (urease, phosphatase, and ß-glucosidase activities, pH, EC, P and CEC). We use the

  7. Assessing different agricultural managements with the use of soil quality indices in a Mediteranean calcareous soil

    NASA Astrophysics Data System (ADS)

    Morugán-Coronado, Alicia; García-Orenes, Fuensanta; Mataix-Solera, Jorge; Arcenegui, Vicky; Cerdà, Artemi

    2013-04-01

    Soil erosion is a major problem in the Mediterranean region due to the arid conditions and torrential rainfalls, which contribute to the degradation of agricultural land. New strategies must be developed to reduce soil losses and recover or maintain soil functionality in order to achieve a sustainable agriculture. An experiment was designed to evaluate the effect of different agricultural management on soil properties and soil quality. Ten different treatments (contact herbicide, systemic herbicide, ploughing, Oat mulch non-plough, Oats mulch plough, leguminous plant, straw rice mulch, chipped pruned branches, residual-herbicide and agro geo-textile, and three control plots including no tillage or control and long agricultural abandonment (shrub on marls and shrub on limestone) were established in 'El Teularet experimental station' located in the Sierra de Enguera (Valencia, Spain). The soil is a Typic Xerorthent developed over Cretaceous marls in an old agricultural terrace. The agricultural management can modify the soil equilibrium and affect its quality. In this work two soil quality indices (models) developed by Zornoza et al. (2007) are used to evaluate the effects of the different agricultural management along 4 years. The models were developed studying different soil properties in undisturbed forest soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. Model 1, that explained 92% of the variance in soil organic carbon (SOC) showed that the SOC can be calculated by the linear combination of 6 physical, chemical and biochemical properties (acid phosphatase, water holding capacity (WHC), electrical conductivity (EC), available phosphorus (P), cation exchange capacity (CEC) and aggregate stability (AS). Model 2 explains 89% of the SOC variance, which can be calculated by means of 7 chemical and biochemical properties (urease, phosphatase, and ß-glucosidase activities, pH, EC, P and CEC). We use the

  8. Effect of land management on soil microbial properties in agricultural terraces of Eastern Spain

    NASA Astrophysics Data System (ADS)

    Morugán-Coronado, Alicia; Cerdà, Artemi; Garcia-Orenes, Fuensanta

    2014-05-01

    Soil quality is important for the sustainable development of terrestrial ecosystems. Agricultural land management is one of most important anthropogenic activities that greatly alters soil characteristics, including physical, chemical, and microbiological properties. The unsuitable land management can lead to a soil fertility loss and to a reduction in the abundance and diversity of soil microorganisms. However, ecological practices and some organic amendments can promote the activities of soil microbial communities, and increase its biodiversity. The microbial soil communities are the most sensitive and rapid indicators of perturbations in land use and soil enzyme activities are sensitive biological indicators of the effects of soil management practices. In this study, a field experiment was performed at clay-loam agricultural soil with an orchard of orange trees in Alcoleja (eastern Spain) to assess the long-term effects of inorganic fertilizers (F), intensive ploughing (P) and sustainable agriculture (S) on the soil microbial biomass carbon (Cmic), enzyme activities (Urease, ß-glucosidase and phosphatase), basal soil repiration (BSR) and the relationship between them, and soil fertility in agro-ecosystems of Spain. Nine soil samples were taken from each agricultural management plot. In all the samples were determined the basal soil respiration, soil microbial biomass carbon, water holding capacity, electrical conductivity, soil organic carbon, nitrogen, available phosphorus, aggregate stability, cation exchange capacity, phosphorous, pH, texture, carbonates, active limestone and as enzimatic activities: Urease, ß-glucosidase and phosphatase. The results showed a substantial level of differentiation in the microbial properties, in terms of management practices, which was highly associated with soil organic matter content. The most marked variation in the different parameters studied appears to be related to sustainable agriculture terrace. The management

  9. Permafrost soils and carbon cycling

    DOE PAGES

    Ping, C. L.; Jastrow, J. D.; Jorgenson, M. T.; Michaelson, G. J.; Shur, Y. L.

    2015-02-05

    Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environment. These efforts significantly increased estimates of the amount of organic carbon stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enormous organic carbon stocks during the Quaternary. This knowledge has also called attention to the importance of permafrost-affected soils to the global carbon cycle and the potential vulnerability of the region's soil organic carbon (SOC) stocks to changing climatic conditions. Inmore » this review, we briefly introduce the permafrost characteristics, ice structures, and cryopedogenic processes that shape the development of permafrost-affected soils, and discuss their effects on soil structures and on organic matter distributions within the soil profile. We then examine the quantity of organic carbon stored in permafrost-region soils, as well as the characteristics, intrinsic decomposability, and potential vulnerability of this organic carbon to permafrost thaw under a warming climate. Overall, frozen conditions and cryopedogenic processes, such as cryoturbation, have slowed decomposition and enhanced the sequestration of organic carbon in permafrost-affected soils over millennial timescales. Due to the low temperatures, the organic matter in permafrost soils is often less humified than in more temperate soils, making some portion of this stored organic carbon relatively vulnerable to mineralization upon thawing of permafrost.« less

  10. The magnetic susceptibility of European agricultural soils

    NASA Astrophysics Data System (ADS)

    Fabian, K.; Reimann, C.

    2012-04-01

    The GEMAS (Geochemical mapping of agricultural soils) project, a cooperation project between EuroGeoSurveys and Eurometaux, aims at providing soil quality data for Europe. Samples of arable soil were taken during 2008 at an average density of 1 site/2500 km2 covering the member states of the European Union (except Malta and Romania) and several neighbouring countries (e.g., Norway, Serbia, Ukraine). While the primary aim of the GEMAS project is to produce REACH (Registration, Evaluation and Authorisation of CHemicals - EC, 2006) consistent soil geochemistry data at the continental scale, the data set is also optimally apt to provide the first continental scale overview of magnetic properties in European soils. Soil samples from the upper 20 cm were taken as composites from 5 sites spread over a ca. 100 m2 area in a large agricultural field (Ap-sample). The samples were air dried and sieved to pass a 2 mm nylon screen. Weight normalized magnetic susceptibility of these dried samples was measured using a Sapphire Instruments SI2B susceptibility meter with dynamic background removal. The here presented maps of magnetic susceptibility in relation to geochemical composition and geological structures for the first time allow to outline the large scale influence of tectonics and climate on magnetic mineral concentration in European soils. The data set also provides the background variability for regional studies aiming to relate magnetic susceptibility of soils to local contamination sources.

  11. Soil organic carbon across scales.

    PubMed

    O'Rourke, Sharon M; Angers, Denis A; Holden, Nicholas M; McBratney, Alex B

    2015-10-01

    Mechanistic understanding of scale effects is important for interpreting the processes that control the global carbon cycle. Greater attention should be given to scale in soil organic carbon (SOC) science so that we can devise better policy to protect/enhance existing SOC stocks and ensure sustainable use of soils. Global issues such as climate change require consideration of SOC stock changes at the global and biosphere scale, but human interaction occurs at the landscape scale, with consequences at the pedon, aggregate and particle scales. This review evaluates our understanding of SOC across all these scales in the context of the processes involved in SOC cycling at each scale and with emphasis on stabilizing SOC. Current synergy between science and policy is explored at each scale to determine how well each is represented in the management of SOC. An outline of how SOC might be integrated into a framework of soil security is examined. We conclude that SOC processes at the biosphere to biome scales are not well understood. Instead, SOC has come to be viewed as a large-scale pool subjects to carbon flux. Better understanding exists for SOC processes operating at the scales of the pedon, aggregate and particle. At the landscape scale, the influence of large- and small-scale processes has the greatest interaction and is exposed to the greatest modification through agricultural management. Policy implemented at regional or national scale tends to focus at the landscape scale without due consideration of the larger scale factors controlling SOC or the impacts of policy for SOC at the smaller SOC scales. What is required is a framework that can be integrated across a continuum of scales to optimize SOC management.

  12. Soil organic carbon across scales.

    PubMed

    O'Rourke, Sharon M; Angers, Denis A; Holden, Nicholas M; McBratney, Alex B

    2015-10-01

    Mechanistic understanding of scale effects is important for interpreting the processes that control the global carbon cycle. Greater attention should be given to scale in soil organic carbon (SOC) science so that we can devise better policy to protect/enhance existing SOC stocks and ensure sustainable use of soils. Global issues such as climate change require consideration of SOC stock changes at the global and biosphere scale, but human interaction occurs at the landscape scale, with consequences at the pedon, aggregate and particle scales. This review evaluates our understanding of SOC across all these scales in the context of the processes involved in SOC cycling at each scale and with emphasis on stabilizing SOC. Current synergy between science and policy is explored at each scale to determine how well each is represented in the management of SOC. An outline of how SOC might be integrated into a framework of soil security is examined. We conclude that SOC processes at the biosphere to biome scales are not well understood. Instead, SOC has come to be viewed as a large-scale pool subjects to carbon flux. Better understanding exists for SOC processes operating at the scales of the pedon, aggregate and particle. At the landscape scale, the influence of large- and small-scale processes has the greatest interaction and is exposed to the greatest modification through agricultural management. Policy implemented at regional or national scale tends to focus at the landscape scale without due consideration of the larger scale factors controlling SOC or the impacts of policy for SOC at the smaller SOC scales. What is required is a framework that can be integrated across a continuum of scales to optimize SOC management. PMID:25918852

  13. Transport of agricultural contaminants through karst soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Karst landscapes are common in many agricultural regions in the US. Well-developed karst landscapes are characterized by shallow soils, sinkholes, sinking streams, underground conduits, and springs. In these landscapes surface runoff is minimal and most recharge enters the subsurface relatively quic...

  14. Agricultural Liming, Irrigation, and Carbon Sequestration

    NASA Astrophysics Data System (ADS)

    McGill, B. M.; Hamilton, S. K.

    2015-12-01

    Row crop farmers routinely add inorganic carbon to soils in the form of crushed lime (e.g., calcite or dolomite minerals) and/or inadvertently as bicarbonate alkalinity naturally dissolved in groundwater used for irrigation. In the soil these carbonates can act as either a source or sink of carbon dioxide, depending in large part on nitrogen fertilization and nitrification. The potentially variable fate of lime carbon is not accounted for in the IPCC greenhouse gas inventory model for lime emissions, which assumes that all lime carbon becomes carbon dioxide (irrigation additions are not accounted for). In a corn-soybean-wheat crop rotation at the Kellogg Biological Station Long Term Ecological Research site in southwest Michigan, we are collecting soil porewater from several depths in the vadose zone across a nitrogen fertilizer gradient with and without groundwater irrigation. The soil profile in this region is dominated by carbonate rich glacial outwash that lies 1.5 m below a carbonate-leached zone. We analyze the porewater stoichiometry of calcium, magnesium, and carbonate alkalinity in a conceptual model to reveal the source/sink fate of inorganic carbon. High nitrate porewater concentrations are associated with net carbon dioxide production in the carbonate-leached zone, according to our model. This suggests that the acidity associated with nitrification of the nitrogen fertilizer, which is evident from soil pH measurements, is driving the ultimate fate of lime carbon in the vadose zone. Irrigation is a significant source of both alkalinity and nitrate in drier years, compared to normal rates of liming and fertilization. We will also explore the observed dramatic changes in porewater chemistry and the relationship between irrigation and inorganic carbon fate above and within the native carbonate layer.

  15. The economics of soil C sequestration and agricultural emissions abatement

    NASA Astrophysics Data System (ADS)

    Alexander, P.; Paustian, K.; Smith, P.; Moran, D.

    2015-04-01

    Carbon is a critical component of soil vitality and is crucial to our ability to produce food. Carbon sequestered in soils also provides a further regulating ecosystem service, valued as the avoided damage from global climate change. We consider the demand and supply attributes that underpin and constrain the emergence of a market value for this vital global ecosystem service: markets being what economists regard as the most efficient institutions for allocating scarce resources to the supply and consumption of valuable goods. This paper considers how a potentially large global supply of soil carbon sequestration is reduced by economic and behavioural constraints that impinge on the emergence of markets, and alternative public policies that can efficiently transact demand for the service from private and public sector agents. In essence, this is a case of significant market failure. In the design of alternative policy options, we consider whether soil carbon mitigation is actually cost-effective relative to other measures in agriculture and elsewhere in the economy, and the nature of behavioural incentives that hinder policy options. We suggest that reducing the cost and uncertainties of mitigation through soil-based measures is crucial for improving uptake. Monitoring and auditing processes will also be required to eventually facilitate wide-scale adoption of these measures.

  16. Soil microbial communities as suitable bioindicators of trace metal pollution in agricultural volcanic soils

    NASA Astrophysics Data System (ADS)

    Parelho, Carolina; dos Santos Rodrigues, Armindo; do Carmo Barreto, Maria; Gonçalo Ferreira, Nuno; Garcia, Patrícia

    2015-04-01

    Summary: The biological, chemical and physical properties of soil confer unique characteristics that enhance or influence its overall biodiversity. The adaptive character of soil microbial communities (SMCs) to metal pollution allows discriminating soil health, since changes in microbial populations and activities may function as excellent indicators of soil pollutants. Volcanic soils are unique naturally fertile resources, extensively used for agricultural purposes and with particular physicochemical properties that may result in accumulation of toxic substances, such as trace metals (TM). In our previous works, we identified priority TM affecting agricultural Andosols under different agricultural land uses. Within this particular context, the objectives of this study were to (i) assess the effect of soil TM pollution in different agricultural systems (conventional, traditional and organic) on the following soil properties: microbial biomass carbon, basal soil respiration, metabolic quotient, enzymatic activities (β-glucosidase, acid phosphatase and dehydrogenase) and RNA to DNA ratio; and (ii) evaluate the impact of TM in the soil ecosystem using the integrated biomarker response (IBR) based on a set of biochemical responses of SMCs. This multi-biomarker approach will support the development of the "Trace Metal Footprint" for different agricultural land uses in volcanic soils. Methods: The study was conducted in S. Miguel Island (Azores, Portugal). Microbial biomass carbon was measured by chloroform-fumigation-incubation-assay (Vance et al., 1987). Basal respiration was determined by the Jenkinson & Powlson (1976) technique. Metabolic quotient was calculated as the ratio of basal respiration to microbial biomass C (Sparkling & West, 1988). The enzymatic activities of β-glucosidase and acid phosphatase were determined by the Dick et al. (1996) method and dehydrogenase activity by the Rossel et al. (1997) method. The RNA and DNA were co-extracted from the same

  17. Global agriculture and carbon trade-offs.

    PubMed

    Johnson, Justin Andrew; Runge, Carlisle Ford; Senauer, Benjamin; Foley, Jonathan; Polasky, Stephen

    2014-08-26

    Feeding a growing and increasingly affluent world will require expanded agricultural production, which may require converting grasslands and forests into cropland. Such conversions can reduce carbon storage, habitat provision, and other ecosystem services, presenting difficult societal trade-offs. In this paper, we use spatially explicit data on agricultural productivity and carbon storage in a global analysis to find where agricultural extensification should occur to meet growing demand while minimizing carbon emissions from land use change. Selective extensification saves ∼ 6 billion metric tons of carbon compared with a business-as-usual approach, with a value of approximately $1 trillion (2012 US dollars) using recent estimates of the social cost of carbon. This type of spatially explicit geospatial analysis can be expanded to include other ecosystem services and other industries to analyze how to minimize conflicts between economic development and environmental sustainability.

  18. Global agriculture and carbon trade-offs

    PubMed Central

    Johnson, Justin Andrew; Runge, Carlisle Ford; Senauer, Benjamin; Foley, Jonathan; Polasky, Stephen

    2014-01-01

    Feeding a growing and increasingly affluent world will require expanded agricultural production, which may require converting grasslands and forests into cropland. Such conversions can reduce carbon storage, habitat provision, and other ecosystem services, presenting difficult societal trade-offs. In this paper, we use spatially explicit data on agricultural productivity and carbon storage in a global analysis to find where agricultural extensification should occur to meet growing demand while minimizing carbon emissions from land use change. Selective extensification saves ∼6 billion metric tons of carbon compared with a business-as-usual approach, with a value of approximately $1 trillion (2012 US dollars) using recent estimates of the social cost of carbon. This type of spatially explicit geospatial analysis can be expanded to include other ecosystem services and other industries to analyze how to minimize conflicts between economic development and environmental sustainability. PMID:25114254

  19. Use of precision agriculture technologies in studying the relationships among soil pH, calcium carbonate equivalent, soybean cyst nematode population density, and soybean yield

    NASA Astrophysics Data System (ADS)

    Rogovska, Natalia

    Iron deficiency chlorosis (IDC) and soybean cyst nematode (SCN; Heterodera glycines) infestation are major factors that contribute to soybean (Glycine max Merr.) yield reduction in the Midwest. The IDC is often associated with soybean grown on high pH, calcareous soils. In addition, it was documented that SCN population density is higher in high pH soils. The objectives of this paper were to assess the proportion of within-field soybean yield and SCN variability that could be explained by soil pH, calcium carbonate equivalent (CCE), and a previously defined alkalinity stress index (ASI). Aerial images from 21 fields planted to SCN-resistant or susceptible soybean varieties were collected from 2001 through 2005 and used as a guide for soil and grain sampling. Ten to 16 sampling sites were selected on each field. Regression analyses within and across sites were used to study relationships between the measured variables. The SCN population density increased and yield decreased with increasing pH, CCE, and ASI across the fields. The percentage of yield variability across fields explained by soil pH, CCE, ASI, and SCN was 13%, 15%, 18%, and 1%, respectively, for resistant soybean varieties and 37%, 24%, 39%, and 10%, respectively, for susceptible varieties. The yield reduction due to high pH, CCE, and ASI was greater for SCN-susceptible varieties in field areas heavily infested with SCN.

  20. Validation of the DNDC model in order to simulate future greenhouse gas emissions and soil carbon changes from the Prairie-Pothole region of North Dakota following prairie conversion to agriculture

    NASA Astrophysics Data System (ADS)

    Suddick, E.; Phillips, R. L.; Waldron, S. E.; Davidson, E. A.

    2012-12-01

    The Prairie Pothole Region (PPR) in North America is home to a diverse range of habitats that support large populations of water fowl and other bird species. Some of the habitats such as the native prairie grasslands of the PPR are under threat due to conversion to cropland. Despite the importance of the PPR, little research has been conducted in this region to understand the impact land-use changes will have on greenhouse gas emissions and soil organic carbon storage (SOC). Therefore, process based biogeochemical models such as the Denitrification Decomposition (DNDC) model can be used to simulate the potential effects that future land-use change will have upon the cycling of carbon and nitrogen in both agricultural and non-agricultural ecosystems. The objective of this study was to validate the DNDC model for two different ecosystems within the PPR region. We aimed to test the ability of the model to predict the flux of the greenhouse gas nitrous oxide (N2O) and SOC changes in both an agricultural cropping system and a natural prairie in order to understand future land use change scenarios and forecast the change in N2O and SOC following prairie conversion to agriculture. Using a baseline climate scenario from observed daily measurements at each site, the DNDC model was tested against observed static chamber field measurements of N2O measured from April 2009 to December 2011, as well as being tested against other ancillary soil measurements (e.g., soil moisture and temperature) from an alfalfa cropping system and a native prairie grassland in the PPR of North Dakota, USA. Soils from the native prairie were classified as a non hydric clay loam with a SOC content of 0.033 kg C kg-1, where the alfalfa cropping system was a non hydric silt loam with a SOC content of 0.019 kg C kg-1. Initial results indicate that simulated N2O emissions at both sites and the change in SOC with conversion of prairie to cropland were generally in agreement with observed field

  1. Carbon sequestration in California agriculture, 1980-2000.

    PubMed

    Kroodsma, David A; Field, Christopher B

    2006-10-01

    To better understand agricultural carbon fluxes in California, USA, we estimated changes in soil carbon and woody material between 1980 and 2000 on 3.6 x 10(6) ha of farmland in California. Combining the CASA (Carnegie-Ames-Stanford Approach) model with data on harvest indices and yields, we calculated net primary production, woody production in orchard and vineyard crops, and soil carbon. Over the 21-yr period, two trends resulted in carbon sequestration. Yields increased an average of 20%, corresponding to greater plant biomass and more carbon returned to the soils. Also, orchards and vineyards increased in area from 0.7 x 10(6) ha to 1.0 x 10(6) ha, displacing field crops and sequestering woody carbon. Our model estimates that California's agriculture sequestered an average of 19 g C x m(-2) x yr(-1). Sequestration was lowest in non-rice annual cropland, which sequestered 9 g C x m(-2) x yr(-1) of soil carbon, and highest on land that switched from annual cropland to perennial cropland. Land that switched from annual crops to vineyards sequestered 68 g C x m(-2) x yr(-1), and land that switched from annual crops to orchards sequestered 85 g C x m(-2) x yr(-1). Rice fields, because of a reduction in field burning, sequestered 55 g C x m(-2) x yr(-1) in the 1990s. Over the 21 years, California's 3.6 x 10(6) ha of agricultural land sequestered 11.0 Tg C within soils and 3.5 Tg C in woody biomass, for a total of 14.5 Tg C statewide. This is equal to 0.7% of the state's total fossil fuel emissions over the same time period. If California's agriculture adopted conservation tillage, changed management of almond and walnut prunings, and used all of its orchard and vineyard waste wood in the biomass power plants in the state, California's agriculture could offset up to 1.6% of the fossil fuel emissions in the state.

  2. Aerosol emissions from biochar-amended agricultural soils

    NASA Astrophysics Data System (ADS)

    Ravi, S.; Sharratt, B. S.; Li, J. J.; Olshvevski, S.; Meng, Z.; Zhang, J.

    2015-12-01

    Agricultural production is a major contributor to anthropogenic greenhouse gas emissions and associated global warming. In this regard, novel carbon sequestration strategies such as large-scale biochar application may provide sustainable pathways to increase the terrestrial storage of carbon in agricultural areas. Biochar has a long residence time in the soil and hence understanding the soil properties affected by biochar addition needs to be investigated to identify the tradeoffs and synergies of large-scale biochar application. Even though several studies have investigated the impacts of biochar application on a variety of soil properties, very few studies have investigated the impacts on soil erosion, in particular wind (aeolian) erosion and subsequent particulate emissions. Using a combination of wind tunnel studies and laboratory experiments, we investigated the dust emission potential of biochar-amended agricultural soils. We amended biochar (unsieved or sieved to appropriate particle size; application rates ranging from 1 - 5 % of the soil by weight) to three soil types (sand, sandy loam, and silt loam) and estimated the changes in threshold shear velocity for wind erosion and dust emission potential in comparison to control soils. Our experiments demonstrate that emissions of fine biochar particles may result from two mechanisms (a) very fine biochar particles (suspension size) that are entrained into the air stream when the wind velocity exceeds the threshold, and (b) production of fine biochar particles originating from the abrasion by quartz grains. The results indicate that biochar application significantly increased particulate emissions and more interestingly, the rate of increase was found to be higher in the intermediate range of biochar application. As fine biochar particles effectively adsorb/trap contaminants and pathogens from the soil, the preferential erosion of fine biochar particles by wind may lead to concentration of contaminants in the

  3. Root Induced Heterogeneity In Agricultural Soils

    NASA Astrophysics Data System (ADS)

    Gomes, C.; Gabai, R.; Weisbrod, N.; Furman, A.

    2012-12-01

    In this study we investigate the role of plant induced heterogeneity on water dynamics in agricultural soils. We conducted three experiments in two sites (one still ongoing) in which a trench was excavated in the root zone of an orchard and the subsurface, to a depth of over 1 m, was instrumented in high resolution with water content, water potential and temperature sensors. High temporal resolution monitoring of soil state was carried for over a year, period that included natural (Mediterranean) climate boundary forcing. In addition, sprinkler, flood, and spray irrigation boundary conditions were forced for short time periods to explore the infiltration process under these conditions. One site was an Avocado orchard planted in red sandy soil while the other, still on-going, is in a grape vineyards irrigated by tap and treated wastewater, planted over alluvial clayey soil. In the vineyard, we are comparing soil irrigated with fresh water to soil irrigated with treated waste water for more than 10 years. Our preliminary results indicate several interesting phenomena. First, the role of plant roots is clearly seen as the major roots act as a conduit for water (and solute), providing a fast bypass of the upper soil. Further, we identified different regions of the subsurface that apparently were of the same texture, but in practice presented very different hydraulic properties. Second, the role of these roots depends on the boundary conditions. That is, the root bypass acts differently when soil is flooded than when flow is strictly unsaturated. As expected, simulation of the experimental results show good fit only if the domain heterogeneity of soil properties was incorporated. Results for the clayey soils were not available at time of abstract submission.

  4. Clumped isotopes in soil carbonate

    NASA Astrophysics Data System (ADS)

    Quade, J.; Eiler, J. M.; Daeron, M.

    2011-12-01

    We are monitoring soil temperature and measuring clumped isotopes from modern soil carbonate in North and South America, Hawaii, and Tibet. Clumped isotopes from 50-200 cm soil depth show a strong and systematic bias toward formation in the warmest summer months. For example, soil carbonate as these depths exceed local mean annual temperature by 10-15°C in soils from India and Tibet. Clumped isotope temperatures from modern carbonate increase very regularly (r2 = 0.90) with elevation gain from lowland India to Tibet. Here carbonate forms largely in May-June, just prior to the arrival of the soil-cooling monsoon rains. In this regard, clumped isotopes hold great promise as a paleoaltimeter on the plateau. The question is whether these patterns from a monsoonal climate can be generalized (and they probably can't be) to other climate regimes when soil carbonate forms at a different time of year than the pre-monsoon. For example, in winter-dominated rainfall regimes soil carbonate may form as soils dewater in the spring and soil temperature is closer to mean annual temperature. These are open questions. Diurnal temperature information is also archived in the upper 30 cm of soils. Modern carbonate in Tibet appears to form in very late morning through afternoon, when the surface soil is warmest. Shade and aspect also strongly influence measured soil and clumped isotope temperatures. Both variables will have to be controlled for to correctly interpret clumped isotopes from the paleosol record. Clumped isotope values correlate with δ13C values in soil carbonate from shallowly buried (<1 km) paleosols from Nepal and Pakistan. This makes sense since δ13C values in the sub-tropics are determined the fraction of tree (C3) to grass (C4) cover, and soils under tree-covered areas are cooler. Finally, clumped isotopes from carbonates are reset to higher temperatures at burial depths roughly >2-3 km or >50-75°C. This was reproduced from paleosol and lake carbonates from three

  5. Cesium and strontium sorption behavior in amended agricultural soils

    NASA Astrophysics Data System (ADS)

    Mehmood, Khalid; Hofmann, Diana; Burauel, Peter; Vereecken, Harry; Berns, Anne E.

    2014-05-01

    Biogas digestates and biochar are emerging soil amendments. Biochar is a byproduct of pyrolysis process which is thermal decomposition of biomass to produce syngas and bio-oil. The use of biochar for soil amendment is being promoted for higher crop yields and carbon sequestration. Currently, the numbers of biogas plants in Germany are increasing to meet the new energy scenarios. The sustainability of biogas industry requires proper disposal options for digestate. Biogas digestates being rich in nutrients are beneficial to enhance agricultural productions. Contrary to the agronomical benefits of these organic amendments, their use can influence the mobility and bioavailability of soil contaminants due to nutrients competition and high organic matter content. So far, the impact of such amendments on highly problematic contaminants like radionuclides is not truly accounted for. In the present study, sorption-desorption behavior of cesium and strontium was investigated in three soils of different origin and texture. Two agricultural soils, a loamy sand and a silty soil, were amended with biochar and digestate in separate experiments, with field application rates of 25 Mg/ha and 34 Mg/ha, respectively. For comparison a third soil, a forest soil, was incubated without any amendment. The amendments were mixed into the top 20 cm of the field soils, resulting in final concentrations of 8-9 g biochar/Kg soil and 11-12 g digestate/Kg soil. The soils were incubated for about six months at room temperature. Sorption-desorption experiments were performed with CsCl and SrCl2 after pre-equilibrating the soils with CaCl2 solutions. The amendments with field application rates did not have a significant effect on the relevant soil parameters responsible for the sorption behavior of the two radionuclides. Comparatively, the soil type lead to distinctive differences in sorption-desorption dynamics of the two radionuclides. Cesium showed a higher affinity for silty soil followed by

  6. Factors controlling carbon metabolism and humification in different soil agroecosystems.

    PubMed

    Doni, S; Macci, C; Peruzzi, E; Ceccanti, B; Masciandaro, G

    2014-01-01

    The aim of this study was to describe the processes that control humic carbon sequestration in soil. Three experimental sites differing in terms of management system and climate were selected: (i) Abanilla-Spain, soil treated with municipal solid wastes in Mediterranean semiarid climate; (ii) Puch-Germany, soil under intensive tillage and conventional agriculture in continental climate; and (iii) Alberese-Italy, soil under organic and conventional agriculture in Mediterranean subarid climate. The chemical-structural and biochemical soil properties at the initial sampling time and one year later were evaluated. The soils under organic (Alberese, soil cultivated with Triticum durum Desf.) and nonintensive management practices (Puch, soil cultivated with Triticum aestivum L. and Avena sativa L.) showed higher enzymatically active humic carbon, total organic carbon, humification index (B/E(3)s), and metabolic potential (dehydrogenase activity/water soluble carbon) if compared with conventional agriculture and plough-based tillage, respectively. In Abanilla, the application of municipal solid wastes stimulated the specific β-glucosidase activity (extracellular β-glucosidase activity/extractable humic carbon) and promoted the increase of humic substances with respect to untreated soil. The evolution of the chemical and biochemical status of the soils along a climatic gradient suggested that the adoption of certain management practices could be very promising in increasing SOC sequestration potential.

  7. Factors Controlling Carbon Metabolism and Humification in Different Soil Agroecosystems

    PubMed Central

    Doni, S.; Macci, C.; Peruzzi, E.; Ceccanti, B.; Masciandaro, G.

    2014-01-01

    The aim of this study was to describe the processes that control humic carbon sequestration in soil. Three experimental sites differing in terms of management system and climate were selected: (i) Abanilla-Spain, soil treated with municipal solid wastes in Mediterranean semiarid climate; (ii) Puch-Germany, soil under intensive tillage and conventional agriculture in continental climate; and (iii) Alberese-Italy, soil under organic and conventional agriculture in Mediterranean subarid climate. The chemical-structural and biochemical soil properties at the initial sampling time and one year later were evaluated. The soils under organic (Alberese, soil cultivated with Triticum durum Desf.) and nonintensive management practices (Puch, soil cultivated with Triticum aestivum L. and Avena sativa L.) showed higher enzymatically active humic carbon, total organic carbon, humification index (B/E3s), and metabolic potential (dehydrogenase activity/water soluble carbon) if compared with conventional agriculture and plough-based tillage, respectively. In Abanilla, the application of municipal solid wastes stimulated the specific β-glucosidase activity (extracellular β-glucosidase activity/extractable humic carbon) and promoted the increase of humic substances with respect to untreated soil. The evolution of the chemical and biochemical status of the soils along a climatic gradient suggested that the adoption of certain management practices could be very promising in increasing SOC sequestration potential. PMID:25614887

  8. Agriculture on Mars: Soils for Plant Growth

    NASA Technical Reports Server (NTRS)

    Ming, D. W.

    2016-01-01

    Robotic rovers and landers have enabled the mineralogical, chemical, and physical characterization of loose, unconsolidated materials on the surface of Mars. Planetary scientists refer to the regolith material as "soil." NASA is currently planning to send humans to Mars in the mid 2030s. Early missions may rely on the use of onsite resources to enable exploration and self-sufficient outposts on Mars. The martian "soil" and surface environment contain all essential plant growth elements. The study of martian surface materials and how they might react as agricultural soils opens a new frontier for researchers in the soil science community. Other potential applications for surface "soils" include (i) sources for extraction of essential plant-growth nutrients, (ii) sources of O2, H2, CO2, and H2O, (iii) substrates for microbial populations in the degradation of wastes, and (iv) shielding materials surrounding outpost structures to protect humans, plants, and microorganisms from radiation. There are many challenges that will have to be addressed by soil scientists prior to human exploration over the next two decades.

  9. Stability of organic carbon in deep soil layers controlled by fresh carbon supply.

    PubMed

    Fontaine, Sébastien; Barot, Sébastien; Barré, Pierre; Bdioui, Nadia; Mary, Bruno; Rumpel, Cornelia

    2007-11-01

    The world's soils store more carbon than is present in biomass and in the atmosphere. Little is known, however, about the factors controlling the stability of soil organic carbon stocks and the response of the soil carbon pool to climate change remains uncertain. We investigated the stability of carbon in deep soil layers in one soil profile by combining physical and chemical characterization of organic carbon, soil incubations and radiocarbon dating. Here we show that the supply of fresh plant-derived carbon to the subsoil (0.6-0.8 m depth) stimulated the microbial mineralization of 2,567 +/- 226-year-old carbon. Our results support the previously suggested idea that in the absence of fresh organic carbon, an essential source of energy for soil microbes, the stability of organic carbon in deep soil layers is maintained. We propose that a lack of supply of fresh carbon may prevent the decomposition of the organic carbon pool in deep soil layers in response to future changes in temperature. Any change in land use and agricultural practice that increases the distribution of fresh carbon along the soil profile could however stimulate the loss of ancient buried carbon.

  10. Single application of Sewage Sludge to an Alluvial Agricultural Soil - impacts on Soil Quality

    NASA Astrophysics Data System (ADS)

    Suhadolc, M.; Graham, D. B.; Hagn, A.; Doerfler, U.; Schloter, M.; Schroll, R.; Munch, J. C.; Lobnik, F.

    2009-04-01

    Limited information exists on the effects of sewage sludge on soil quality with regard to their ability to maintain soil functions. We studied effects of sewage sludge amendment on soil chemical properties, microbial community structure and microbial degradation of the herbicide glyphosate. Three months soil column leaching experiment has been conducted using alluvial soils (Eutric Fluvisol) with no prior history of sludge application. The soil was loamy with pH 7,4 and organic matter content of 3,5%. Soil material in the upper 2 cm of columns was mixed with dehydrated sewage sludge which was applied in amounts corresponding to the standards governing the use of sewage sludge for agricultural land. Sludge did increase some nutrients (total N, NH4+, available P and K, organic carbon) and some heavy metals contents (Zn, Cu, Pb) in soil. However, upper limits for heavy metals in agricultural soils were not exceeded. Results of heavy metal availability in soil determined by sequential extraction will be also presented. Restriction fragment length polymorphism (RFLP) analyses of 16s/18s rDNA, using universal fungal and bacterial primers, revealed clear shifts in bacterial and fungal community structure in the upper 2 cm of soils after amendment. Fungal fingerprints showed greater short term effects of sewage sludge, whereas sewage sludge seems to have prolonged effects on soil bacteria. Furthermore, sewage sludge amendment significantly increased glyphosate degradation from 21.6±1% to 33.6±1% over a 2 months period. The most probable reasons for shifts in microbial community structure and increased degradation of glyphosate are beneficial alterations to the physical-chemical characteristics of the soil. Negative effects of potentially toxic substances present in the sewage sludge on soil microbial community functioning were not observed with the methods used in our study.

  11. Carbon consequences and agricultural implications of growing biofuel crops on marginal agricultural lands in China.

    PubMed

    Qin, Zhangcai; Zhuang, Qianlai; Zhu, Xudong; Cai, Ximing; Zhang, Xiao

    2011-12-15

    Using marginal agricultural lands to grow energy crops for biofuel feedstocks is a promising option to meet the biofuel needs in populous China without causing further food shortages or environmental problems. Here we quantify the effects of growing switchgrass and Miscanthus on Chinese marginal agricultural lands on biomass production and carbon emissions with a global-scale biogeochemical model. We find that the national net primary production (NPP) of these two biofuel crops are 622 and 1546 g C m(-2) yr(-1), respectively, whereas the NPP of food crops is about 600 g C m(-2) yr(-1) in China. The net carbon sink over the 47 Mha of marginal agricultural lands across China is 2.1 Tg C yr(-1) for switchgrass and 5.0 Tg C yr(-1) for Miscanthus. Soil organic carbon is estimated to be 10 kg C m(-2) in both biofuel ecosystems, which is equal to the soil carbon levels of grasslands in China. In order to reach the goal of 12.5 billion liters of bioethanol in 2020 using crop biomass as biofuel feedstocks, 7.9-8.0 Mha corn grain, 4.3-6.1 Mha switchgrass, or 1.4-2.0 Mha Miscanthus will be needed. Miscanthus has tremendous potential to meet future biofuel needs, and to benefit CO(2) mitigation in China.

  12. Modelling agricultural suitability along soil transects under current conditions and improved scenario of soil factors

    NASA Astrophysics Data System (ADS)

    Abd-Elmabod, Sameh K.; Jordán, Antonio; Fleskens, Luuk; van der Ploeg, Martine; Muñoz-Rojas, Miriam; Anaya-Romero, María; van der Salm, Renée J.; De la Rosa, Diego

    2015-04-01

    Agricultural land suitability analysis and improvement of soils by addressing major limitations may be a strategy for climate change adaptation. This study aims to investigate the influence of topography and variability of soil factors on the suitability of 12 annual, semiannual and perennial Mediterranean crops in the province of Seville (southern Spain). In order to represent the variability in elevation, lithology and soil, two latitudinal and longitudinal (S-N and W-E) soil transects (TA and TB) were considered including 63 representative points at regular 4 km intervals. These points were represented by 41 soil profiles from the SDBm soil database -Seville. Almagra model, a component of the agro-ecological decision support system MicroLEIS, was used to assess soil suitability. Results were grouped into five soil suitability classes: S1-optimum, S2-high, S3-moderate, S4-marginal and S5-not suitable. Each class was divided in subclasses according to the main soil limiting factors: depth (p), texture (t), drainage (d), carbonate content (c), salinity (s), sodium saturation (a), and the degree of development of the soil profile (g). This research also aimed to maximize soil potential by improving limiting factors d, c, s and a after soil restoration. Therefore, management techniques were also considered as possible scenarios in this study. The results of the evaluation showed that soil suitability ranged between S1 and S5p - S5s along of the transects. In the northern extreme of transect TA, high content of gravels and coarse texture are limiting factors (soils are classified as S4t) In contrast, the limiting factor in the eastern extreme of transect TB is the shallow useful depth (S5p subclass). The absence of calcium carbonate becomes a limiting factor in some parts of TA. In contrast, the excessive content of calcium carbonate appeared to be a limiting factor for crops in some intermediate points of TB transect. For both transects, soil salinity is the main

  13. Ranking factors affecting emissions of GHG from incubated agricultural soils

    PubMed Central

    García-Marco, S; Ravella, S R; Chadwick, D; Vallejo, A; Gregory, A S; Cárdenas, L M

    2014-01-01

    Agriculture significantly contributes to global greenhouse gas (GHG) emissions and there is a need to develop effective mitigation strategies. The efficacy of methods to reduce GHG fluxes from agricultural soils can be affected by a range of interacting management and environmental factors. Uniquely, we used the Taguchi experimental design methodology to rank the relative importance of six factors known to affect the emission of GHG from soil: nitrate (NO3−) addition, carbon quality (labile and non-labile C), soil temperature, water-filled pore space (WFPS) and extent of soil compaction. Grassland soil was incubated in jars where selected factors, considered at two or three amounts within the experimental range, were combined in an orthogonal array to determine the importance and interactions between factors with a L16 design, comprising 16 experimental units. Within this L16 design, 216 combinations of the full factorial experimental design were represented. Headspace nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) concentrations were measured and used to calculate fluxes. Results found for the relative influence of factors (WFPS and NO3− addition were the main factors affecting N2O fluxes, whilst glucose, NO3− and soil temperature were the main factors affecting CO2 and CH4 fluxes) were consistent with those already well documented. Interactions between factors were also studied and results showed that factors with little individual influence became more influential in combination. The proposed methodology offers new possibilities for GHG researchers to study interactions between influential factors and address the optimized sets of conditions to reduce GHG emissions in agro-ecosystems, while reducing the number of experimental units required compared with conventional experimental procedures that adjust one variable at a time. PMID:25177207

  14. Ranking factors affecting emissions of GHG from incubated agricultural soils.

    PubMed

    García-Marco, S; Ravella, S R; Chadwick, D; Vallejo, A; Gregory, A S; Cárdenas, L M

    2014-07-01

    Agriculture significantly contributes to global greenhouse gas (GHG) emissions and there is a need to develop effective mitigation strategies. The efficacy of methods to reduce GHG fluxes from agricultural soils can be affected by a range of interacting management and environmental factors. Uniquely, we used the Taguchi experimental design methodology to rank the relative importance of six factors known to affect the emission of GHG from soil: nitrate (NO3 (-)) addition, carbon quality (labile and non-labile C), soil temperature, water-filled pore space (WFPS) and extent of soil compaction. Grassland soil was incubated in jars where selected factors, considered at two or three amounts within the experimental range, were combined in an orthogonal array to determine the importance and interactions between factors with a L16 design, comprising 16 experimental units. Within this L16 design, 216 combinations of the full factorial experimental design were represented. Headspace nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) concentrations were measured and used to calculate fluxes. Results found for the relative influence of factors (WFPS and NO3 (-) addition were the main factors affecting N2O fluxes, whilst glucose, NO3 (-) and soil temperature were the main factors affecting CO2 and CH4 fluxes) were consistent with those already well documented. Interactions between factors were also studied and results showed that factors with little individual influence became more influential in combination. The proposed methodology offers new possibilities for GHG researchers to study interactions between influential factors and address the optimized sets of conditions to reduce GHG emissions in agro-ecosystems, while reducing the number of experimental units required compared with conventional experimental procedures that adjust one variable at a time. PMID:25177207

  15. Greenhouse gas fluxes from agricultural soils of Kenya and Tanzania

    NASA Astrophysics Data System (ADS)

    Rosenstock, Todd S.; Mpanda, Mathew; Pelster, David E.; Butterbach-Bahl, Klaus; Rufino, Mariana C.; Thiong'o, Margaret; Mutuo, Paul; Abwanda, Sheila; Rioux, Janie; Kimaro, Anthony A.; Neufeldt, Henry

    2016-06-01

    Knowledge of greenhouse gas (GHG) fluxes in soils is a prerequisite to constrain national, continental, and global GHG budgets. However, data characterizing fluxes from agricultural soils of Africa are markedly limited. We measured carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) fluxes at 10 farmer-managed sites of six crop types for 1 year in Kenya and Tanzania using static chambers and gas chromatography. Cumulative emissions ranged between 3.5-15.9 Mg CO2-C ha-1 yr-1, 0.4-3.9 kg N2O-N ha-1 yr-1, and -1.2-10.1 kg CH4-C ha-1 yr-1, depending on crop type, environmental conditions, and management. Manure inputs increased CO2 (p = 0.03), but not N2O or CH4, emissions. Soil cultivation had no discernable effect on emissions of any of the three gases. Fluxes of CO2 and N2O were 54-208% greater (p < 0.05) during the wet versus the dry seasons for some, but not all, crop types. The heterogeneity and seasonality of fluxes suggest that the available data describing soil fluxes in Africa, based on measurements of limited duration of only a few crop types and agroecological zones, are inadequate to use as a basis for estimating the impact of agricultural soils on GHG budgets. A targeted effort to understand the magnitude and mechanisms underlying African agricultural soil fluxes is necessary to accurately estimate the influence of this source on the global climate system and for determining mitigation strategies.

  16. Soil macronutrient sensing for precision agriculture.

    PubMed

    Kim, Hak-Jin; Sudduth, Kenneth A; Hummel, John W

    2009-10-01

    Accurate measurements of soil macronutrients (i.e., nitrogen, phosphorus, and potassium) are needed for efficient agricultural production, including site-specific crop management (SSCM), where fertilizer nutrient application rates are adjusted spatially based on local requirements. Rapid, non-destructive quantification of soil properties, including nutrient levels, has been possible with optical diffuse reflectance sensing. Another approach, electrochemical sensing based on ion-selective electrodes or ion-selective field effect transistors, has been recognized as useful in real-time analysis because of its simplicity, portability, rapid response, and ability to directly measure the analyte with a wide range of sensitivity. Current sensor developments and related technologies that are applicable to the measurement of soil macronutrients for SSCM are comprehensively reviewed. Examples of optical and electrochemical sensors applied in soil analyses are given, while advantages and obstacles to their adoption are discussed. It is proposed that on-the-go vehicle-based sensing systems have potential for efficiently and rapidly characterizing variability of soil macronutrients within a field.

  17. Carbon sequestration potential of soils in southeast Germany derived from stable soil organic carbon saturation.

    PubMed

    Wiesmeier, Martin; Hübner, Rico; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Reischl, Arthur; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2014-02-01

    Sequestration of atmospheric carbon (C) in soils through improved management of forest and agricultural land is considered to have high potential for global CO2 mitigation. However, the potential of soils to sequester soil organic carbon (SOC) in a stable form, which is limited by the stabilization of SOC against microbial mineralization, is largely unknown. In this study, we estimated the C sequestration potential of soils in southeast Germany by calculating the potential SOC saturation of silt and clay particles according to Hassink [Plant and Soil 191 (1997) 77] on the basis of 516 soil profiles. The determination of the current SOC content of silt and clay fractions for major soil units and land uses allowed an estimation of the C saturation deficit corresponding to the long-term C sequestration potential. The results showed that cropland soils have a low level of C saturation of around 50% and could store considerable amounts of additional SOC. A relatively high C sequestration potential was also determined for grassland soils. In contrast, forest soils had a low C sequestration potential as they were almost C saturated. A high proportion of sites with a high degree of apparent oversaturation revealed that in acidic, coarse-textured soils the relation to silt and clay is not suitable to estimate the stable C saturation. A strong correlation of the C saturation deficit with temperature and precipitation allowed a spatial estimation of the C sequestration potential for Bavaria. In total, about 395 Mt CO2 -equivalents could theoretically be stored in A horizons of cultivated soils - four times the annual emission of greenhouse gases in Bavaria. Although achieving the entire estimated C storage capacity is unrealistic, improved management of cultivated land could contribute significantly to CO2 mitigation. Moreover, increasing SOC stocks have additional benefits with respect to enhanced soil fertility and agricultural productivity.

  18. EPIC modeling of soil organic carbon sequestration in croplands of Iowa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural lands can mitigate detrimental effects of greenhouse gases because soils can be managed to reduce carbon dioxide emissions and sequester carbon in soil organic matter. Simulation models are useful tools for studying the long-term impacts of crop and soil management practices on soil org...

  19. Organic farming enhances soil carbon and its benefits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing soil carbon through systematic agricultural practices provides an array of societal and farmer/producer benefits. Organic methods have been utilized for over 6000 years to conserve soil, water, energy, and biological resources. Many of the benefits of organic technologies identified in ...

  20. Influence of sustainable management on aggregate stability and soil organic matter on agricultural soil of southern Spain

    NASA Astrophysics Data System (ADS)

    Morugan-Coronado, Alicia; Arcenegui, Victoria; Mataix-Solera, Jorge; Gomez-Lucas, Ignacio; Garcia-Orenes, Fuensanta

    2016-04-01

    Intensive agriculture has increased crop yields but also posed severe environmental problems. Unsustainable land management such as excessive tillage can lead to a loss of soil fertility and a drastic reduction in the aggregate stability and soil organic matter content. However sustainable agriculture can keep good crop yields with minimal impact on ecological factors conserving the soil quality and its ecosystem services. Sustainable agriculture management promotes the maintenance of soil organic matter levels providing plant nutrients through the microbial decomposition of organic materials. Also this management has a positive effect on soil structure with the improvement of stability of aggregates. The resistance of soil aggregates to the slaking and dispersive effects of water (aggregate stability) is important for maintaining the structure in arable soils. Our purpose was to investigate and compare the effects of sustainable agricultural practices versus intensive agriculture on aggregate stability and soil organic matter. Three agricultural areas are being monitored in the southern of Spain, two of them with citrus orchards (AL) and (FE) and one with grapevine(PA). In all of them two agricultural treatments are being developed, organic with no-tillage management(O) and inorganic fertilization with herbicide application and intensive tillage (I). The sustainable agricultural management (manure, no tillage and vegetation cover) contributed to the improve of soil conditions, increasing organic matter and aggregate stability. Meanwhile, herbicide treatment and intensive tillage with inorganic fertilization managements resulted in the decreasing of aggregate stability and low levels of soil organic carbon. Soil organic matter content is generally low in all unsustainable treatments plots and tends to decline in aggregate stability and soil physical condition. In both treatments the crop yield are comparable.

  1. Elevated atmospheric carbon dioxide increases soil carbon

    SciTech Connect

    Norby, Richard J; Jastrow, Julie D; Miller, Michael R; Matamala, Roser; Boutton, Thomas W; Rice, Charles W; Owensby, Clenton E

    2005-01-01

    In a study funded by the U.S. Department of Energy's Office of Science, researchers from Argonne and Oak Ridge National Laboratories and Kansas State and Texas A&M Universities evaluated the collective results of earlier studies by using a statistical procedure called meta-analysis. They found that on average elevated CO2 increased soil carbon by 5.6 percent over a two to nine year period. They also measured comparable increases in soil carbon for Tennessee deciduous forest and Kansas grassland after five to eight years of experimental exposure to elevated CO2.

  2. Time course of soil carbon storage, 15N and radiocarbon signature in top- and subsoil of a 60-years agricultural field trial - indications for compensating effects of carbon input and turnover

    NASA Astrophysics Data System (ADS)

    Leifeld, Jens; Conen, Franz; Oberholzer, Hans Rudolf; Jochen, Mayer

    2014-05-01

    Soil carbon dynamics are controlled by the delicate balance between carbon inputs and outputs which both are co-regulated by land use and management (LUM) as important anthropogenic drivers. Upon land use change to cropland carbon stocks generally tend to decline but often the contribution of two opposing factors, namely changes in input and decomposition rates, to soil carbon stock changes is indistinguishable. Here we report on an ongoing cropland experiment in Zurich, Switzerland, named ZOFE (Zurich Organic Fertilization Experiment), established on former grassland in 1949. ZOFE encompasses a range of mineral and organic fertilization practices and a zero fertilizer treatment as control. The experiment has a block design with five replicates per treatment. We make use of productivity and fertilization gradients in selected treatments of the ZOFE trial to evaluate how low or high inputs (induced by differential yields and organic fertilization) may affect soil organic carbon storage and transformation. For the most recent sampling that also included subsoil down to 0.9 m, all properties were measured for every single replicate. Topsoil carbon storage declined after grassland conversion at rates of c. 0.2 t C ha-1 a-1, particularly in treatments with mineral fertilizer and high yields, and without fertilization and low yields. Organic matter amendments such as manure or compost could partially offset but not fully compensate some of the topsoil carbon loss. Over time the soil's delta 15N signature declined as well, probably due to increased atmospheric nitrogen deposition. It increased from the top- to the subsoil, indicating increasing microbial transformation, particularly with manure added. The soil's radiocarbon signature revealed distinct bomb peak patterns in all treatments but only in the topsoil. The 14C data confirmed that with higher productivity more recent organic matter was incorporated, both in top and subsoil. Because, in contrast to topsoil

  3. Combining agricultural practices key to elevating soil microbial activities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The concept of soil health is an emerging topic in applied ecology, specifically as it pertains to the agriculture, which utilizes approximately 40% of earth’s land. However, rigorous quantification of soil health and the services provided by soil organisms to support agriculture production (e.g., n...

  4. Soil carbon dynamics in cropland and rangeland.

    PubMed

    Lal, R

    2002-01-01

    Most soils in the Midwestern USA have lost 30 to 50% of their original pool, or 25 to 40 Mg C/ha, upon conversion from natural to agricultural ecosystems. About 60 to 70% of the C thus depleted can be resequestered through adoption of recommended soil and crop management practices. These practices include conversion from plow till to no till, frequent use of winter cover crops in the rotation cycle, elimination of summer fallow, integrated nutrient management along with liberal use of biosolids and biological nitrogen fixation, precision farming to minimize losses and enhance fertilizer use efficiency, and use of improved varieties with ability to produce large root biomass with high content of lignin and suberin. The gross rate of soil organic carbon (SOC) sequestration ranges from 500 to 800 kg/ha/year in cold and humid regions and 100 to 300 kg/ha/year in dry and warm regions. The rate of SOC sequestration can be measured with procedures that are cost effective and credible at soil pedon level, landscape level, regional or national scale. In addition to SOC, there is also a large potential to sequester soil inorganic carbon (SIC) in arid and semi-arid regions. Soil C sequestration has numerous ancillary benefits. It is truly a win-win situation: extremely cost-effective, and a bridge to the future until alternative energy options take effect.

  5. CO2 emissions from organic soils under agricultural use

    NASA Astrophysics Data System (ADS)

    Bader, Cédric; Leifeld, Jens; Müller, Moritz; Schulin, Rainer

    2015-04-01

    The organic soils of peatlands represent a major global sink for terrestrial carbon. Agricultural use of organic soils requires drainage, changing conditions in these soils from anoxic to oxic. As a consequence, the organic carbon that had been accumulated often over millennia is rapidly mineralized, so that these soils then are no longer a sink but become a source of CO2. The aim of our study is to analyse the amount and origin of CO2 emitted from organic soils under three land-use types (forest, arable cropland and grassland). Our study area is located in the Bernese Lakeland (CH). The peatlands of this region were drained in the 1870ies, and the site as well as the surrounding area are now managed by a state prison. Since decades our study site is under the same land-use. In Oktober 2013 we took 4 replicate soil cores of all land-uses with respect to a certain distance from a major drainage ditch. Each core was analysed for its bulk density and carbon content. 9 soil samples from a depth of 20-30 cm were analysed for their F14C and δ13C values and later divided into 18 subsamples. Half of them were mixed with 0.2-0.4 g of labelled corn stalk enriched in δ13C (δ13C=2000) in order to mimic plant residue inputs in the field. The moisture content of these samples was equilibrated at a pF-value of 2 before incubating the samples in a Respicond VII analyser for several weeks at 20° C. By trapping the respired CO2 in NaOH and precipitating it as BaCO3 we were able to analyse its F14C and δ13C value. This enabled us to determine to what extent the CO2 originated from old peat, young plant residues or the added maize stalk. Generally the cropland samples showed the highest respiration rates, lowest F14C values and highest carbon stocks. The organic soils under the forest were degraded the most and showed low respiration rates. Analyzing the F14C values of the CO2 revealed that peat contributes most to the respiration and its degradation is fastest in the cropland

  6. Ammonia- and methane-oxidizing microorganisms in high-altitude wetland sediments and adjacent agricultural soils.

    PubMed

    Yang, Yuyin; Shan, Jingwen; Zhang, Jingxu; Zhang, Xiaoling; Xie, Shuguang; Liu, Yong

    2014-12-01

    Ammonia oxidation is known to be carried out by ammonia-oxidizing bacteria (AOB) and archaea (AOA), while methanotrophs (methane-oxidizing bacteria (MOB)) play an important role in mitigating methane emissions from the environment. However, the difference of AOA, AOB, and MOB distribution in wetland sediment and adjacent upland soil remains unclear. The present study investigated the abundances and community structures of AOA, AOB, and MOB in sediments of a high-altitude freshwater wetland in Yunnan Province (China) and adjacent agricultural soils. Variations of AOA, AOB, and MOB community sizes and structures were found in water lily-vegetated and Acorus calamus-vegetated sediments and agricultural soils (unflooded rice soil, cabbage soil, and garlic soil and flooded rice soil). AOB community size was higher than AOA in agricultural soils and lily-vegetated sediment, but lower in A. calamus-vegetated sediment. MOB showed a much higher abundance than AOA and AOB. Flooded rice soil had the largest AOA, AOB, and MOB community sizes. Principal coordinate analyses and Jackknife Environment Clusters analyses suggested that unflooded and flooded rice soils had relatively similar AOA, AOB, and MOB structures. Cabbage soil and A. calamus-vegetated sediment had relatively similar AOA and AOB structures, but their MOB structures showed a large difference. Nitrososphaera-like microorganisms were the predominant AOA species in garlic soil but were present with a low abundance in unflooded rice soil and cabbage soil. Nitrosospira-like AOB were dominant in wetland sediments and agricultural soils. Type I MOB Methylocaldum and type II MOB Methylocystis were dominant in wetland sediments and agricultural soils. Moreover, Pearson's correlation analysis indicated that AOA Shannon diversity was positively correlated with the ratio of organic carbon to nitrogen (p < 0.05). This work could provide some new insights toward ammonia and methane oxidation in soil and wetland sediment

  7. Unexpected stimulation of soil methane uptake as emergent property of agricultural soils following bio-based residue application.

    PubMed

    Ho, Adrian; Reim, Andreas; Kim, Sang Yoon; Meima-Franke, Marion; Termorshuizen, Aad; de Boer, Wietse; van der Putten, Wim H; Bodelier, Paul L E

    2015-10-01

    Intensification of agriculture to meet the global food, feed, and bioenergy demand entail increasing re-investment of carbon compounds (residues) into agro-systems to prevent decline of soil quality and fertility. However, agricultural intensification decreases soil methane uptake, reducing, and even causing the loss of the methane sink function. In contrast to wetland agricultural soils (rice paddies), the methanotrophic potential in well-aerated agricultural soils have received little attention, presumably due to the anticipated low or negligible methane uptake capacity in these soils. Consequently, a detailed study verifying or refuting this assumption is still lacking. Exemplifying a typical agricultural practice, we determined the impact of bio-based residue application on soil methane flux, and determined the methanotrophic potential, including a qualitative (diagnostic microarray) and quantitative (group-specific qPCR assays) analysis of the methanotrophic community after residue amendments over 2 months. Unexpectedly, after amendments with specific residues, we detected a significant transient stimulation of methane uptake confirmed by both the methane flux measurements and methane oxidation assay. This stimulation was apparently a result of induced cell-specific activity, rather than growth of the methanotroph population. Although transient, the heightened methane uptake offsets up to 16% of total gaseous CO2 emitted during the incubation. The methanotrophic community, predominantly comprised of Methylosinus may facilitate methane oxidation in the agricultural soils. While agricultural soils are generally regarded as a net methane source or a relatively weak methane sink, our results show that methane oxidation rate can be stimulated, leading to higher soil methane uptake. Hence, even if agriculture exerts an adverse impact on soil methane uptake, implementing carefully designed management strategies (e.g. repeated application of specific residues) may

  8. Unexpected stimulation of soil methane uptake as emergent property of agricultural soils following bio-based residue application.

    PubMed

    Ho, Adrian; Reim, Andreas; Kim, Sang Yoon; Meima-Franke, Marion; Termorshuizen, Aad; de Boer, Wietse; van der Putten, Wim H; Bodelier, Paul L E

    2015-10-01

    Intensification of agriculture to meet the global food, feed, and bioenergy demand entail increasing re-investment of carbon compounds (residues) into agro-systems to prevent decline of soil quality and fertility. However, agricultural intensification decreases soil methane uptake, reducing, and even causing the loss of the methane sink function. In contrast to wetland agricultural soils (rice paddies), the methanotrophic potential in well-aerated agricultural soils have received little attention, presumably due to the anticipated low or negligible methane uptake capacity in these soils. Consequently, a detailed study verifying or refuting this assumption is still lacking. Exemplifying a typical agricultural practice, we determined the impact of bio-based residue application on soil methane flux, and determined the methanotrophic potential, including a qualitative (diagnostic microarray) and quantitative (group-specific qPCR assays) analysis of the methanotrophic community after residue amendments over 2 months. Unexpectedly, after amendments with specific residues, we detected a significant transient stimulation of methane uptake confirmed by both the methane flux measurements and methane oxidation assay. This stimulation was apparently a result of induced cell-specific activity, rather than growth of the methanotroph population. Although transient, the heightened methane uptake offsets up to 16% of total gaseous CO2 emitted during the incubation. The methanotrophic community, predominantly comprised of Methylosinus may facilitate methane oxidation in the agricultural soils. While agricultural soils are generally regarded as a net methane source or a relatively weak methane sink, our results show that methane oxidation rate can be stimulated, leading to higher soil methane uptake. Hence, even if agriculture exerts an adverse impact on soil methane uptake, implementing carefully designed management strategies (e.g. repeated application of specific residues) may

  9. Soybean fungal soil-borne diseases: a parameter for measuring the effect of agricultural intensification on soil health.

    PubMed

    Pérez-Brandán, C; Huidobro, J; Grümberg, B; Scandiani, M M; Luque, A G; Meriles, J M; Vargas-Gil, S

    2014-02-01

    The aim of this study was to investigate the influence of agricultural intensification on soil microbial diversity, chemical and physical parameters, and the decrease of the incidence of sudden death syndrome (Fusarium crassistipitatum) and charcoal rot (Macrophomina phaseolina) in soybean. Soils under different management systems were evaluated during 2 crop cycles: soybean monoculture for 24 and 11 years, soybean-maize rotation for 15 and 4 years, 1 year of soybean, and native vegetation. The incidence of both soil-borne diseases was higher under monoculture than under rotation. Increased populations of potential biocontrol agents (Trichoderma spp., Gliocladium spp., fluorescent pseudomonads) were associated with rotation treatments, especially in 2010-2011. The comparison of agricultural vs. native vegetation soil and the average of agricultural cycles showed that microbial biomass carbon and glomalin-related soil protein were higher in the rotation system than in monoculture (50% and 77%, respectively). Furthermore, from the community-level functional diversity (Biolog Eco plates), McIntosh index showed lower functional diversity in monoculture than in rotation and native vegetation plots. Agricultural intensification reduced microbial biomass carbon, glomalin-related soil protein, organic matter, total nitrogen, aggregate stability, and yield, and increased bulk density. Soil quality degradation was associated with the establishment of soil-borne pathogens and increased soybean plant susceptibility to disease.

  10. Soybean fungal soil-borne diseases: a parameter for measuring the effect of agricultural intensification on soil health.

    PubMed

    Pérez-Brandán, C; Huidobro, J; Grümberg, B; Scandiani, M M; Luque, A G; Meriles, J M; Vargas-Gil, S

    2014-02-01

    The aim of this study was to investigate the influence of agricultural intensification on soil microbial diversity, chemical and physical parameters, and the decrease of the incidence of sudden death syndrome (Fusarium crassistipitatum) and charcoal rot (Macrophomina phaseolina) in soybean. Soils under different management systems were evaluated during 2 crop cycles: soybean monoculture for 24 and 11 years, soybean-maize rotation for 15 and 4 years, 1 year of soybean, and native vegetation. The incidence of both soil-borne diseases was higher under monoculture than under rotation. Increased populations of potential biocontrol agents (Trichoderma spp., Gliocladium spp., fluorescent pseudomonads) were associated with rotation treatments, especially in 2010-2011. The comparison of agricultural vs. native vegetation soil and the average of agricultural cycles showed that microbial biomass carbon and glomalin-related soil protein were higher in the rotation system than in monoculture (50% and 77%, respectively). Furthermore, from the community-level functional diversity (Biolog Eco plates), McIntosh index showed lower functional diversity in monoculture than in rotation and native vegetation plots. Agricultural intensification reduced microbial biomass carbon, glomalin-related soil protein, organic matter, total nitrogen, aggregate stability, and yield, and increased bulk density. Soil quality degradation was associated with the establishment of soil-borne pathogens and increased soybean plant susceptibility to disease. PMID:24498984

  11. Hydrological controls on heterotrophic soil respiration across an agricultural landscape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water availability is an important determinant of variation in soil respiration, but a consistent relationship between soil water and the relative flux rate of carbon dioxide across different soil types remains elusive. Using large undisturbed soil columns (N = 12), we evaluated soil water controls...

  12. Biological and biochemical soil indicators: monitoring tools of different agricultural managements

    NASA Astrophysics Data System (ADS)

    Scotti, Riccardo; Sultana, Salma; Scelza, Rosalia; Marzaioli, Rossana; D'Ascoli, Rosaria; Rao, Maria A.

    2010-05-01

    on fertility of both soils under intensive farming. In general, all enzymatic activities and organic carbon content increased after 1 month, and they were still higher after 4 months from amendment application. Microbial biomass and soil potential activity (respiration) showed significantly higher values in soils added with organic amendments, for both farms and samplings, with more marked effects on respiration in the first sampling. In conclusion results showed, in general, a quick response as indicators of the assayed biological and biochemical soil properties and a good recovery in fertility of the studied agricultural soils. The project was founded by CCIIAA of Salerno

  13. Incorporating Agricultural Management Practices into the Assessment of Soil Carbon Change and Life-Cycle Greenhouse Gas Emissions of Corn Stover Ethanol Production

    SciTech Connect

    Qin, Zhangcai; Canter, Christina E.; Dunn, Jennifer B.; Mueller, Steffen; Kwon, Ho-young; Han, Jeongwoo; Wander, Michelle M.; Wang, Michael

    2015-09-01

    Land management practices such as cover crop adoption or manure application that can increase soil organic carbon (SOC) may provide a way to counter SOC loss upon removal of stover from corn fields for use as a biofuel feedstock. This report documents the data, methodology, and assumptions behind the incorporation of land management practices into corn-soybean systems that dominate U.S. grain production using varying levels of stover removal in the GREETTM (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model and its CCLUB (Carbon Calculator for Land Use change from Biofuels production) module. Tillage (i.e., conventional, reduced and no tillage), corn stover removal (i.e., at 0, 30% and 60% removal rate), and organic matter input techniques (i.e., cover crop and manure application) are included in the analysis as major land management practices. Soil carbon changes associated with land management changes were modeled with a surrogate CENTURY model. The resulting SOC changes were incorporated into CCLUB while GREET was expanded to include energy and material consumption associated with cover crop adoption and manure application. Life-cycle greenhouse gas (GHG) emissions of stover ethanol were estimated using a marginal approach (all burdens and benefits assigned to corn stover ethanol) and an energy allocation approach (burdens and benefits divided between grain and stover ethanol). In the latter case, we considered corn grain and corn stover ethanol to be produced at an integrated facility. Life-cycle GHG emissions of corn stover ethanol are dependent upon the analysis approach selected (marginal versus allocation) and the land management techniques applied. The expansion of CCLUB and GREET to accommodate land management techniques can produce a wide range of results because users can select from multiple scenario options such as choosing tillage levels, stover removal rates, and whether crop yields increase annually or remain constant

  14. Sustained stimulation of soil respiration and CO2 release from an agricultural soil after 10 years of experimental warming

    NASA Astrophysics Data System (ADS)

    Munch, Jean Charles; Graf, Wolfgang; Reichenstein, Markus; Reth, Sascha

    2010-05-01

    A number of forest and grassland studies indicated that stimulation of the soil respiration by soil warming ceases after a couple of years (Luo et al 2001). A long-term soil warming lysimeter experiment (soil monolythes from an agricultural field, 1m2 x 2 Meter depth, temperature = ambient + 3°C; with a regionally usual crop rotation with 5 crops) was conducted in southern Germany. It results in a sustained stimulation of soil respiration after 10 years. Moreover, both warmed and control treatments exhibited a similar temperature response of soil respiration indicating that adaptation in terms of temperature sensitivity was absent. Carbon dioxide concentration measurements within the profiles are supporting these findings. The increased soil respiration occurred although vegetation productivity in the warmed treatment was not higher than in the control plots. These findings strongly contrast current soil carbon modeling concepts, where carbon pools decay according to first-order kinetics, and thus a depletion of labile soil carbon pools leads to an apparent down-regulation of microbial respiration (Knorr et al 2005). Consequently, the potential for positive carbon-climate cycle feedback may be larger than represented in current models of soil carbon turnover and in general assessments. Literatur Knorr W, Prentice I C, House J I and Holland A 2005 Long-term sensitivity of soil carbon turnover to warming Nature 433 298-301 Luo Y, Wan S, Hui D and Wallace L L 2001 Acclimatization of soil respiration to warming in a tall grass prairie Nature 413 622 - 5 Reth S. Graf W, Reichenstein M, Munch J.C. 2009 Sustained stimulation of soil respiration after 10 years of experimental warming Environmental Research Letters 4(2) 024005

  15. Soil Organic Carbon Change Monitored Over Large Areas

    SciTech Connect

    Brown, David J.; Hunt, E. Raymond; Izaurralde, Roberto C.; Paustian, Keith H.; Rice, Charles W.; Schumaker, Bonny L.; West, Tristram O.

    2010-11-23

    Soils account for the largest fraction of terrestrial carbon (C) and thus are critically important in determining global cycle dynamics. In North America, conversion of native prairies to agriculture over the past 150 years released 30- 50% of soil organic carbon (SOC) stores [Mann, 1986]. Improved agricultural practices could recover much of this SOC, storing it in biomass and soil and thereby sequestering billions of tons of atmospheric carbon dioxide (CO2). These practices involve increasing C inputs to soil (e.g., through crop rotation, higher biomass crops, and perennial crops) and decreasing losses (e.g., through reduced tillage intensity) [Janzen et al., 1998; Lal et al., 2003; Smith et al., 2007].

  16. Soil microbial community response to land use change in an agricultural landscape of western Kenya.

    PubMed

    Bossio, D A; Girvan, M S; Verchot, L; Bullimore, J; Borelli, T; Albrecht, A; Scow, K M; Ball, A S; Pretty, J N; Osborn, A M

    2005-01-01

    Tropical agroecosystems are subject to degradation processes such as losses in soil carbon, nutrient depletion, and reduced water holding capacity that occur rapidly resulting in a reduction in soil fertility that can be difficult to reverse. In this research, a polyphasic methodology has been used to investigate changes in microbial community structure and function in a series of tropical soils in western Kenya. These soils have different land usage with both wooded and agricultural soils at Kakamega and Ochinga, whereas at Ochinga, Leuro, Teso, and Ugunja a replicated field experiment compared traditional continuous maize cropping against an improved N-fixing fallow system. For all sites, principal component analysis of 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) profiles revealed that soil type was the key determinant of total bacterial community structure, with secondary variation found between wooded and agricultural soils. Similarly, phospholipid fatty acid (PLFA) analysis also separated wooded from agricultural soils, primarily on the basis of higher abundance of monounsaturated fatty acids, anteiso- and iso-branched fatty acids, and methyl-branched fatty acids in the wooded soils. At Kakamega and Ochinga wooded soils had between five 5 and 10-fold higher levels of soil carbon and microbial biomass carbon than agricultural soils from the same location, whereas total enzyme activities were also lower in the agricultural sites. Soils with woody vegetation had a lower percentage of phosphatase activity and higher cellulase and chitinase activities than the agricultural soils. BIOLOG analysis showed woodland soils to have the greatest substrate diversity. Throughout the study the two functional indicators (enzyme activity and BIOLOG), however, showed lower specificity with respect to soil type and land usage than did the compositional indicators (DGGE and PLFA). In the field experiment comparing two types of maize cropping, both the maize yields

  17. Burkholderia cordobensis sp. nov., from agricultural soils.

    PubMed

    Draghi, Walter O; Peeters, Charlotte; Cnockaert, Margo; Snauwaert, Cindy; Wall, Luis G; Zorreguieta, Angeles; Vandamme, Peter

    2014-06-01

    Two Gram-negative, rod-shaped bacteria were isolated from agricultural soils in Córdoba province in central Argentina. Their 16S rRNA gene sequences demonstrated that they belong to the genus Burkholderia, with Burkholderia zhejiangensis as most closely related formally named species; this relationship was confirmed through comparative gyrB sequence analysis. Whole-cell fatty acid analysis supported their assignment to the genus Burkholderia. Burkholderia sp. strain YI23, for which a whole-genome sequence is available, represents the same taxon, as demonstrated by its highly similar 16S rRNA (100% similarity) and gyrB (99.1-99.7%) gene sequences. The results of DNA-DNA hybridization experiments and physiological and biochemical characterization further substantiated the genotypic and phenotypic distinctiveness of the Argentinian soil isolates, for which the name Burkholderia cordobensis sp. nov. is proposed, with strain MMP81(T) ( = LMG 27620(T) = CCUG 64368(T)) as the type strain.

  18. Linking soil functions to carbon fluxes and stocks

    NASA Astrophysics Data System (ADS)

    Olesen, Jørgen E.

    2014-05-01

    Farming practices causing declining returns and inputs of carbon (C) to soils pose threats to sustainable soil functioning by reducing availability of organic matter for soil microbial activities and by affecting soil structure, and soil C stocks that contribute to regulating greenhouse gas emissions. Declines in soil C also affect availability and storage capacity of a range of essential plant nutrients thus affecting needs for external inputs. Soil degradation is considered a serious problem in Europe and a large part of the degradation is caused by agricultural activity with intensive cultivation in arable and mixed farming system contributing to several soil threats. About 45% of European soils are estimated to have low SOM content, principally in southern Europe, but also in areas of France, UK and Germany. The European SOC stocks follow a clear north to south gradient with cooler temperatures favouring higher stocks. However, SOC stocks strongly depend on soil and land management, and there is thus a potential to both increase and lose SOC, although the potential to increase SOC strongly depends on incentives and structures for implementing improved management. Understanding the role of soil C may be better conceptualised by using a soil C flow and stocks concept to assess the impact of C management on crop productivity, soil organic C stocks and other ecosystem services. This concept distinguishes C flows and stocks, which may be hypothesized to have distinctly different effects on biological, chemical and physical soil functions. By separating the roles of carbon flows from the role of carbon stocks, it may become possible to better identify critical levels not only of soil carbon stocks, but also critical levels of carbon inputs, which directly relate to needs for crop and soil management measures. Such critical soil carbon stocks may be linked to soil mineralogy through complexed organic carbon on clay and silt surfaces. Critical levels of soil carbon

  19. Worldwide organic soil carbon and nitrogen data

    SciTech Connect

    Zinke, P.J.; Stangenberger, A.G.; Post, W.M.; Emanual, W.R.; Olson, J.S.

    1986-09-01

    The objective of the research presented in this package was to identify data that could be used to estimate the size of the soil organic carbon pool under relatively undisturbed soil conditions. A subset of the data can be used to estimate amounts of soil carbon storage at equilibrium with natural soil-forming factors. The magnitude of soil properties so defined is a resulting nonequilibrium values for carbon storage. Variation in these values is due to differences in local and geographic soil-forming factors. Therefore, information is included on location, soil nitrogen content, climate, and vegetation along with carbon density and variation.

  20. Permafrost soils and carbon cycling

    DOE PAGES

    Ping, C. L.; Jastrow, J. D.; Jorgenson, M. T.; Michaelson, G. J.; Shur, Y. L.

    2014-10-30

    Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environment. These efforts significantly increased estimates of the amount of organic carbon (OC) stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enormous OC stocks during the Quaternary. This knowledge has also called attention to the importance of permafrost-affected soils to the global C cycle and the potential vulnerability of the region's soil OC stocks to changing climatic conditions. In this review,more » we briefly introduce the permafrost characteristics, ice structures, and cryopedogenic processes that shape the development of permafrost-affected soils and discuss their effects on soil structures and on organic matter distributions within the soil profile. We then examine the quantity of OC stored in permafrost-region soils, as well as the characteristics, intrinsic decomposability, and potential vulnerability of this OC to permafrost thaw under a warming climate.« less

  1. Biogeochemistry: Soil carbon in a beer can

    NASA Astrophysics Data System (ADS)

    Davidson, Eric A.

    2015-10-01

    Decomposition of soil organic matter could be an important positive feedback to climate change. Geochemical properties of soils can help determine what fraction of soil carbon may be protected from climate-induced decomposition.

  2. Straw management effects on CO2 efflux and C storage in different Mediterranean agricultural soils.

    PubMed

    Badía, David; Martí, Clara; Aguirre, Angel J

    2013-11-01

    The crop residues buried in semiarid soils as a carbon sink are evaluated. Both C-CO2 evolved and C sequestered from agricultural soils amended with barley straw were measured seasonally over 2 farming seasons in a semiarid environment (NE Spain). Six experimental soils with low organic matter content and contrasted properties were selected. The CO2 efflux, as a result of soil microbial activity, showed a significant seasonal variation according to changes in both soil moisture and temperature being the spring and early summer when respiration rates get higher. On annual average, more organic, calcareous soils, evolved higher carbon dioxide efflux (up to 53 mg CO2/kg and day) than soils with high levels of gypsum or more soluble salts (up to 25 mg CO2/kg and day), which have a lower percentage of organic carbon. Straw residue incorporation increases these CO2 emissions significantly for each soil type. Although CO2 emissions are significantly and negatively correlated with the C storage, straw addition increases soil organic C content, at the end of the period of study. In calcareous soils were stored up to 550 kgC/ha and year, gypseous soils up to 1135 kgC/ha and year and saline soils up to 1450 kgC/ha and year. According to the amount of stored C in the different soil types, the isohumic coefficient of barley straw ranges from 0.087 to 0.259 (kg of humus formed from 1 kg of dry straw).

  3. Agricultural legacies in forest environments: tree communities, soil properties, and light availability.

    PubMed

    Flinn, Kathryn M; Marks, P L

    2007-03-01

    Temperate deciduous forests across much of Europe and eastern North America reflect legacies of past land use, particularly in the diversity and composition of plant communities. Intense disturbances, such as clearing forests for agriculture, may cause persistent environmental changes that continue to shape vegetation patterns as landscapes recover. We assessed the long-term consequences of agriculture for environmental conditions in central New York forests, including tree community structure and composition, soil physical and chemical properties, and light availability. To isolate the effects of agriculture, we compared 20 adjacent pairs of forests that were never cleared for agriculture (primary forests) and forests that established 85-100 years ago on plowed fields (secondary forests). Tree communities in primary and secondary forests had similar stem density, though secondary forests had 14% greater basal area. Species composition differed dramatically between the two forest types, with primary forests dominated by Acer saccharum and Fagus grandifolia and secondary forests by Acer rubrum and Pinus strobus. Primary and secondary forests showed no consistent differences in soil physical properties or in the principal gradient of soil fertility associated with soil pH. Within stands, however, soil water content and pH were more variable in primary forests. Secondary forest soils had 15% less organic matter, 16% less total carbon, and 29% less extractable phosphorus in the top 10 cm than adjacent primary stands, though the ranges of the forest types mostly overlapped. Understory light availability in primary and secondary forests was similar. These results suggest that, within 100 years, post-agricultural stands have recovered conditions comparable to less disturbed forests in many attributes, including tree size and number, soil physical properties, soil chemical properties associated with pH, and understory light availability. The principal legacies of

  4. Colluvial soils as a carbon pool in different soil regions

    NASA Astrophysics Data System (ADS)

    Zádorová, Tereza; Penížek, Vít; Žížala, Daniel

    2014-05-01

    Distribution and storage of soil organic matter are controlled by various environmental factors. In areas influenced by soil erosion, the soil organic carbon (SOC) pattern is characterized by both its removal in some parts and its storage in other parts of the landscape. Colluvial soils formed by accumulation of soil sediments represent such a carbon pool. SOC stock in colluvial soils was determined and related to terrain attributes on three agricultural plots (from 7 to 30 hectares) with different soil and geologic (Cambisol, Luvisol and Chernozem) character. The analysis was also focused on differences in SOC distribution in topsoil and subsoil. The study was based on a detailed network of soil borings and deep cores. SOC content was determined in each 25 cm in entire A horizon up to the depth of 5 m. SOC density determined in each point using SOC concentration, bulk density and A horizon thickness was statistically related to various terrain attributes derived from a detailed digital elevation model. Grid of SOC density was obtained by interpolating point measurements using the terrain attributes as accessory variables; the total SOC stock was then calculated by summing the grid cells. In Chernozem and Luvisol regions, SOC stock is strongly related to the terrain character when topographic wetness index and plan curvature were the most significantly related to the distribution of SOC density. In Cambisol region, low relationship between SOC distribution and terrain attributes was observed. Thickness of A horizon is variable in the three plots: its depth reaches up to 5 meters in Chernozem region while in Luvisol and Cambisol the maximum observed thickness was 1 meter. SOC density averages from the three plots are 7.63 kg.m-2 (Cambisol), 12.06 kg.m-2 (Luvisol) and 32.28 kg.m-2 (Chernozem). SOC stock in the topsoil (0-30 cm) represents 54.5 % in Cambisol region, 43.6 % in Luvisol region and only 19.3 % in Chernozem region from the total SOC stock. This finding

  5. Ibuprofen adsorption in four agricultural volcanic soils.

    PubMed

    Estevez, Esmeralda; Hernandez-Moreno, Jose Manuel; Fernandez-Vera, Juan Ramon; Palacios-Diaz, Maria Pino

    2014-01-15

    Ibuprofen (IB) is a high environmental risk drug and one of the most frequently prescribed in human medicine. Recently, IB has been detected in Gran Canaria in reclaimed water for irrigation and in groundwater. Adsorption was studied in four volcanic soils from three islands of the Canarian Archipelago. Once the biodegradation process has been excluded from the experimental conditions, a batch method was applied using initial concentrations of 1-5-10-20-50-100-200 mg L(-1) and two soil/water ratios (w/V): 1:5 (OECD, 2000) and 1:1. Non-linear and linearized Langmuir and Freundlich equations were well fitted. The wide IB range tested in our batch studies allowed us to measure experimental adsorption values close to the maximum adsorption capacity (S(max)) as estimated by Langmuir, making it possible thereby to validate the use of the Langmuir equation when there is a burst of contamination at high concentration. The distribution coefficient (Kd), S(max) and Retardation Factor (RF) varied from 0.04 to 0.5 kg L(-1), 4-200 mgk g(-1) and 1.2-1.9, respectively. The lowest S(max) and Kd values were found for the 1:1S/W ratio whereas most batch studies employ 1:5S/W ratios, thus obtaining higher adsorption parameters than when considering field conditions (1:1). Despite the high anion retention of andic soils, similar Kd and RF to those reported for other soils were obtained in 1:5, while high S(max) was found. Our results demonstrate that IB adsorption in volcanic areas responds not only to the soil properties commonly cited in adsorption studies, but also depends on andic properties, sorbent concentration and Dissolved Organic Carbon, the higher values of which are related to the lower Kd and S(max). The low RF and low detection frequency of the IB in groundwater suggests that a) reclaimed water irrigation is not the main source of IB, and b) the existence of some uncontrolled water disposal points in the zone.

  6. Estimations of soil fertility in physically degraded agricultural soils through selective accounting of fine earth and gravel fractions

    NASA Astrophysics Data System (ADS)

    Nagaraja, Mavinakoppa S.; Bhardwaj, Ajay Kumar; Prabhakara Reddy, G. V.; Srinivasamurthy, Chilakunda A.; Kumar, Sandeep

    2016-06-01

    Soil fertility and organic carbon (C) stock estimations are crucial to soil management, especially that of degraded soils, for productive agricultural use and in soil C sequestration studies. Currently, estimations based on generalized soil mass (hectare furrow basis) or bulk density are used which may be suitable for normal agricultural soils, but not for degraded soils. In this study, soil organic C, available nitrogen (N), available phosphorus (P2O5) and available potassium (K2O), and their stocks were estimated using three methods: (i) generalized soil mass (GSM, 2 million kg ha-1 furrow soil), (ii) bulk-density-based soil mass (BDSM) and (iii) the proportion of fine earth volume (FEV) method, for soils sampled from physically degraded lands in the eastern dry zone of Karnataka State in India. Comparative analyses using these methods revealed that the soil organic C, N, P2O and K2O stocks determined by using BDSM were higher than those determined by the GSM method. The soil organic C values were the lowest in the FEV method. The GSM method overestimated soil organic C, N, P2O and K2O by 9.3-72.1, 9.5-72.3, 7.1-66.6 and 9.2-72.3 %, respectively, compared to FEV-based estimations for physically degraded soils. The differences among the three methods of estimation were lower in soils with low gravel content and increased with an increase in gravel volume. There was overestimation of soil organic C and soil fertility with GSM and BDSM methods. A reassessment of methods of estimation was, therefore, attempted to provide fair estimates for land development projects in degraded lands.

  7. Bacterial indicator of agricultural management for soil under no-till crop production.

    PubMed

    Figuerola, Eva L M; Guerrero, Leandro D; Rosa, Silvina M; Simonetti, Leandro; Duval, Matías E; Galantini, Juan A; Bedano, José C; Wall, Luis G; Erijman, Leonardo

    2012-01-01

    The rise in the world demand for food poses a challenge to our ability to sustain soil fertility and sustainability. The increasing use of no-till agriculture, adopted in many areas of the world as an alternative to conventional farming, may contribute to reduce the erosion of soils and the increase in the soil carbon pool. However, the advantages of no-till agriculture are jeopardized when its use is linked to the expansion of crop monoculture. The aim of this study was to survey bacterial communities to find indicators of soil quality related to contrasting agriculture management in soils under no-till farming. Four sites in production agriculture, with different soil properties, situated across a west-east transect in the most productive region in the Argentinean pampas, were taken as the basis for replication. Working definitions of Good no-till Agricultural Practices (GAP) and Poor no-till Agricultural Practices (PAP) were adopted for two distinct scenarios in terms of crop rotation, fertilization, agrochemicals use and pest control. Non-cultivated soils nearby the agricultural sites were taken as additional control treatments. Tag-encoded pyrosequencing was used to deeply sample the 16S rRNA gene from bacteria residing in soils corresponding to the three treatments at the four locations. Although bacterial communities as a whole appeared to be structured chiefly by a marked biogeographic provincialism, the distribution of a few taxa was shaped as well by environmental conditions related to agricultural management practices. A statistically supported approach was used to define candidates for management-indicator organisms, subsequently validated using quantitative PCR. We suggest that the ratio between the normalized abundance of a selected group of bacteria within the GP1 group of the phylum Acidobacteria and the genus Rubellimicrobium of the Alphaproteobacteria may serve as a potential management-indicator to discriminate between sustainable vs. non

  8. [Effects of Green Manure Intercropping and Straw Mulching on Winter Rape Rhizosphere Soil Organic Carbon and Soil Respiration].

    PubMed

    Zhou, Quan; Wang, Long-chang; Xiong, Ying; Zhang, Sai; Du, Juan; Zhao, Lin-lu

    2016-03-15

    Under the background of global warming, the farmland soil respiration has become the main way of agricultural carbon emissions. And green manure has great potential to curb greenhouse gas emissions and achieve energy conservation and emissions reduction. However, in purple soil region of Southwest, China, soil respiration under green manure remains unclear, especially in the winter and intercropping. Through the green manure ( Chinese milk vetch) intercropping with rape, therefore, we compared the effects of rape rhizosphere under straw mulching. The soil organic carbon and soil respiration were examined. The results showed, compared with straw mulching, root separation was the major influencing factors of soil organic carbon on rape rhizosphere. Soil organic carbon was significantly decreased by root interaction. In addition, straw mulching promoted while green manure intercropping inhibited the soil respiration. Soil respiration presented the general characteristics of fall-rise-fall due to the strong influence of rape growth period. Therefore, it showed a cubic curve relationship with soil temperature.

  9. [Effects of Green Manure Intercropping and Straw Mulching on Winter Rape Rhizosphere Soil Organic Carbon and Soil Respiration].

    PubMed

    Zhou, Quan; Wang, Long-chang; Xiong, Ying; Zhang, Sai; Du, Juan; Zhao, Lin-lu

    2016-03-15

    Under the background of global warming, the farmland soil respiration has become the main way of agricultural carbon emissions. And green manure has great potential to curb greenhouse gas emissions and achieve energy conservation and emissions reduction. However, in purple soil region of Southwest, China, soil respiration under green manure remains unclear, especially in the winter and intercropping. Through the green manure ( Chinese milk vetch) intercropping with rape, therefore, we compared the effects of rape rhizosphere under straw mulching. The soil organic carbon and soil respiration were examined. The results showed, compared with straw mulching, root separation was the major influencing factors of soil organic carbon on rape rhizosphere. Soil organic carbon was significantly decreased by root interaction. In addition, straw mulching promoted while green manure intercropping inhibited the soil respiration. Soil respiration presented the general characteristics of fall-rise-fall due to the strong influence of rape growth period. Therefore, it showed a cubic curve relationship with soil temperature. PMID:27337908

  10. Can biosolids reduce wind erosion of agricultural soils?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The application of biosolids to agricultural land has the potential to improve soil health and crop production. In addition, organic material contained in biosolids may enhance biological activity, retention of soil water, and soil aggregation. Thus, there is a likelihood that biosolids applied to s...

  11. 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...

  12. Impact of woodchip biochar amendment on the sorption and dissipation of pesticide acetamiprid in agricultural soils.

    PubMed

    Yu, Xiang-Yang; Mu, Chang-Li; Gu, Cheng; Liu, Cun; Liu, Xian-Jin

    2011-11-01

    Pyrolysis of vegetative biomass into biochar and application of the more stable form of carbon to soil have been shown to be effective in reducing the emission of greenhouse gases, improving soil fertility, and sequestering soil contaminants. However, there is still lack of information about the impact of biochar amendment in agricultural soils on the sorption and environmental fate of pesticides. In this study, we investigated the sorption and dissipation of a neonicotinoid insecticide acetamiprid in three typical Chinese agricultural soils, which were amended by a red gum wood (Eucalyptus spp.) derived biochar. Our results showed that the amendment of biochar (0.5% (w/w)) to the soils could significantly increase the sorption of acetamiprid, but the magnitudes of enhancement were varied. Contributions of 0.5% newly-added biochar to the overall sorption of acetamiprid were 52.3%, 27.4% and 11.6% for red soil, paddy soil and black soil, respectively. The dissipation of acetamiprid in soils amended with biochar was retarded compared to that in soils without biochar amendment. Similar to the sorption experiment, in soil with higher content of organic matter, the retardation of biochar on the dissipation of acetamiprid was lower than that with lower content of organic matter. The different effects of biochar in agricultural soils may attribute to the interaction of soil components with biochar, which would block the pore or compete for binding site of biochar. Aging effect of biochar application in agricultural soils and field experiments need to be further investigated. PMID:21862101

  13. Using soil redistribution to understand soil organic carbon redistribution and budgets

    USGS Publications Warehouse

    Ritchie, J.C.; McCarty, G.W.; Venteris, E.R.; Kaspar, T.C.

    2005-01-01

    Patterns of soil organic carbon (SOC) vary across the landscape leading to uncertainties in SOC budgets, especially for agricultural areas where water, wind, and tillage erosion redistribute soil and SOC. This study determined SOC patterns related to soil redistribution in small agricultural fields. Soil redistribution patterns were determined using the fallout caesium-137 technique in agricultural fields in Maryland and Iowa, USA. In two Iowa fields, SOC ranged from 0.5 to 5% whereas in the Maryland field the SOC ranged from 0.4 to 2.9%. Soil organic carbon was statistically significantly correlated with soil 137Cs inventories and soil erosion/deposition rates. Sites of soil erosion in Iowa and Maryland had significantly lower average concentrations of SOC (2.4% and 1.3%, respectively) than sites of soil deposition (3.4% and 1.6%, respectively). These studies show the impact of soil redistribution patterns, within a field or catchment, and aid in understanding SOC patterns and budgets.

  14. Soil type as factor controlling the effects of forest transformation to agricultural use in soil aggregation and related properties

    NASA Astrophysics Data System (ADS)

    Chrenková, Katarína; Mataix-Solera, Jorge; Dlapa, Pavel; Arcenegui, Victoria

    2014-05-01

    AS due to agricultural land use. Soil WR was found in three of the sites, and its presence plays a key role in the aggregation and its stability, especially in one of the sites with severe WR, since that type of soil is very sandy and despite we expected initially a very low aggregation, the results showed 38 and 62% of AS for agricultural use and forest respectively, which is comparable to other soils with high clay and carbonates content as stabilizing agents. The MWD was in most cases higher in forest than in agricultural sites, except of two wettable sandy soils with the lowest initial AS, where the MWD was higher in agricultural sites. As conclusions we can say that the use of tillage in agriculture affects aggregate stability, but the magnitude is quite dependent of the soil organic matter, the texture and the presence of WR. Some soils can be much more vulnerable than others to land use. In some cases the presence of hydrophobic substances can play a key role in the formation and stabilization of soil aggregates, contributing to maintain good levels of OM and avoiding higher levels of soil degradation. References: Angers, D.A., N.Samson, and A.Légere. 1993. Early changes in water-stable aggregation induced by rotation and tillage in a soil under barley production. Canadian J. Soil Sci. 73: 51-59. Tisdall, J.M., Oades, J.M., 1982. Organic matter and water-stable aggregates in soils. J. Soil Sci. 62, 141-163.

  15. Remote Sensing to Support Monitoring of Soil Organic Carbon (Invited)

    NASA Astrophysics Data System (ADS)

    McNairn, H.; Pacheco, A.

    2009-12-01

    Soil organic carbon is fundamental to the sustainability of agricultural soils and soils play an important role in the global carbon balance. Estimating soil carbon levels and monitoring changes in these levels over time requires extensive data on climate, soil properties, land cover and land management. Remote sensing technologies are capable of providing some of the data needed in modeling soil organic carbon concentrations and in tracking changes in soil carbon. The characteristics of the vegetation cover influence the amount of organic matter in the soil and cultivation impacts the rate of organic matter decomposition. Consequently land management decisions, which include cropping and tillage practices, play a vital role in determining soil carbon levels. Agriculture and Agri-Food Canada (AAFC) has developed several methods to map land management practices from multispectral and Synthetic Aperture Radar (SAR) satellite sensors. These include identification of crops grown, estimation of crop residue cover left post-harvest and identification of tillage activities. Optical and SAR data are capable of identifying crop types to accuracies consistently above 85%. Knowledge of crop type also provides information needed to establish biomass levels and residue type, both of which influence the amounts and decomposition rates of organic matter. Scientists with AAFC have also extensively validated a method to estimate percent residue cover using spectral unmixing analysis applied to multispectral satellite data. Percentages for corn, soybean and small grain residues can be estimated to accuracies of 83%, 80% and 82%, respectively. Tillage activity influences residue decomposition and AAFC is investigating methods to identify tillage occurrence using advanced polarimetric SAR information. This presentation will provide an overview of methods and results from research ongoing at AAFC. The potential contribution of these remote sensing approaches to support wide area carbon

  16. Economic and Societal Benefits of Soil Carbon Management (Chapter 1).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many papers and books on soil carbon management have addressed specific ecosystems such as agricultural lands, rangelands, forestlands, etc. This paper introduces a book within which each chapter begins by addressing a particular concern and potential options to manage it, along with their real and...

  17. Agriculture Canada Central Saskatchewan Vector Soils Data

    NASA Technical Reports Server (NTRS)

    Knapp, David; Hall, Forrest G. (Editor); Rostad, Harold

    2000-01-01

    This data set consists of GIS layers that describe the soils of the BOREAS SSA. These original data layers were submitted as vector data in ARC/INFO EXPORT format. These data also include the soil name and soil layer files, which provide additional information about the soils. There are three sets of attributes that include information on the primary, secondary, and tertiary soil type within each polygon. Thus, there is a total of nine main attributes in this data set.

  18. Ecosystem Services in Agricultural Landscapes: A Spatially Explicit Approach to Support Sustainable Soil Management

    PubMed Central

    Crossman, Neville D.; MacEwan, Richard J.; Wallace, D. Dugal; Bennett, Lauren T.

    2014-01-01

    Soil degradation has been associated with a lack of adequate consideration of soil ecosystem services. We demonstrate a broadly applicable method for mapping changes in the supply of two priority soil ecosystem services to support decisions about sustainable land-use configurations. We used a landscape-scale study area of 302 km2 in northern Victoria, south-eastern Australia, which has been cleared for intensive agriculture. Indicators representing priority soil services (soil carbon sequestration and soil water storage) were quantified and mapped under both a current and a future 25-year land-use scenario (the latter including a greater diversity of land uses and increased perennial crops and irrigation). We combined diverse methods, including soil analysis using mid-infrared spectroscopy, soil biophysical modelling, and geostatistical interpolation. Our analysis suggests that the future land-use scenario would increase the landscape-level supply of both services over 25 years. Soil organic carbon content and water storage to 30 cm depth were predicted to increase by about 11% and 22%, respectively. Our service maps revealed the locations of hotspots, as well as potential trade-offs in service supply under new land-use configurations. The study highlights the need to consider diverse land uses in sustainable management of soil services in changing agricultural landscapes. PMID:24616632

  19. Ecosystem services in agricultural landscapes: a spatially explicit approach to support sustainable soil management.

    PubMed

    Forouzangohar, Mohsen; Crossman, Neville D; MacEwan, Richard J; Wallace, D Dugal; Bennett, Lauren T

    2014-01-01

    Soil degradation has been associated with a lack of adequate consideration of soil ecosystem services. We demonstrate a broadly applicable method for mapping changes in the supply of two priority soil ecosystem services to support decisions about sustainable land-use configurations. We used a landscape-scale study area of 302 km(2) in northern Victoria, south-eastern Australia, which has been cleared for intensive agriculture. Indicators representing priority soil services (soil carbon sequestration and soil water storage) were quantified and mapped under both a current and a future 25-year land-use scenario (the latter including a greater diversity of land uses and increased perennial crops and irrigation). We combined diverse methods, including soil analysis using mid-infrared spectroscopy, soil biophysical modelling, and geostatistical interpolation. Our analysis suggests that the future land-use scenario would increase the landscape-level supply of both services over 25 years. Soil organic carbon content and water storage to 30 cm depth were predicted to increase by about 11% and 22%, respectively. Our service maps revealed the locations of hotspots, as well as potential trade-offs in service supply under new land-use configurations. The study highlights the need to consider diverse land uses in sustainable management of soil services in changing agricultural landscapes.

  20. Production and characterization of biochars from agricultural by-products for use in soil quality enhancement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    By-products are produced in significant amounts from crop residues such as pecan shells (PC), peanut shells (PS), and cotton gin (CG) trash. These residues can be used to produce biochar suitable for use in agricultural soil to sequester carbon and enhance plant growth by supplying and retaining nut...

  1. Accelerated export of sediment and carbon from a landscape under intensive agriculture.

    PubMed

    Glendell, M; Brazier, R E

    2014-04-01

    The export of total organic carbon (particulate and dissolved) from terrestrial to aquatic ecosystems has important implications for water quality and the global carbon cycle. However, most research to date has focused on DOC losses from either forested or peaty catchments, with only limited studies examining the controls and rates of total fluvial carbon losses from agricultural catchments, particularly during storm events. This study examined the controls and fluxes of total suspended sediment (SS), total particulate (TPC) and dissolved organic carbon (DOC) from two adjacent catchments with contrasting intensive agricultural and semi-natural land-use. Data from 35 individual storm events showed that the agricultural catchment exported significantly higher SS concentrations on a storm-by-storm basis than the semi-natural catchment, with peak discharge exerting a greater control over SS, TPC and DOC concentrations. Baseflow DOC concentrations in the agricultural catchment were significantly higher. DOC quality monitored during one simultaneous rainfall event differed between the two study catchments, with more humic, higher molecular weight compounds prevailing in the agricultural catchment and lower molecular weight compounds prevailing in the semi-natural catchment. During an eight month period for which a comparable continuous turbidity record was available, the estimated SS yields from the agricultural catchment were higher than from the semi-natural catchment. Further, the agricultural catchment exported proportionally more TPC and a comparable amount of DOC, despite a lower total soil carbon pool. These results suggest that altered hydrological and biogeochemical processes within the agricultural catchment, including accelerated soil erosion and soil organic matter turnover, contributed to an enhanced fluvial SS and carbon export. Thus, we argue that enhancing semi-natural vegetation within intensively farmed catchments could reduce sediment and carbon losses

  2. Limits to soil carbon stability; Deep, ancient soil carbon decomposition stimulated by new labile organic inputs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil carbon (C) pools store about one-third of the total terrestrial organic carbon. Deep soil C pools (below 1 m) are thought to be stable due to their low biodegradability, but little is known about soil microbial processes and carbon dynamics below the soil surface, or how global change might aff...

  3. Soil conservation under climate change: use of recovery biomasses on agricultural soil subjected to the passage of agricultural machinery

    NASA Astrophysics Data System (ADS)

    Bergonzoli, S.; Beni, C.; Servadio, P.

    2012-04-01

    sugar content and hardness of the tap-roots. The use of compost in right amount improved soil qualities, as evidenced by enhanced workability of the soil and increased hydraulic conductivity, which allow limiting the effects of exceptional weather events, typical of the climate change. The net balance of carbon is enhanced in these plots, providing energy and cost savings associated with increases in production, while carrots were characterized by a high quality standard, with tap-roots of good size, having increased sweetness and higher firmness. Key words: Soil functional quality, Traffic, Compost, Carrot Acknowledgements This work was carried out under the auspices of the special project "Sceneries of adaptation of the Italian agriculture to the climatic changes" (AGROSCENARI) of the Agricultural Research Council, and Italian Ministry of the Agricultural and Forestry Politics.

  4. Impact of an intensive management on soil biochemical and biological properties in an agricultural soil of Southern Italy

    NASA Astrophysics Data System (ADS)

    Scotti, R.; D'Ascoli, R.; Rao, M. A.; Marzaioli, R.; Rutigliano, F. A.; Gianfreda, L.

    2009-04-01

    within a greenhouse or within a field, for control soils. Every sample was formed by 5 sub-samples collected in 5 different points following a W scheme in the plot. All samples, sieved at 2 mm mesh, were stored at 4 °C and characterized by analysing the following soil physical and chemical, properties: soil texture, bulk density, water content, water holding capacity, pH, cation exchange capacity, organic carbon, total nitrogen, phosphorus, potassium, sodium, lime, and electrical conductivity were determined. Moreover the activity of dehydrogenase, beta-glucosidase, urease, phosphatase, and arilsulphatase, the enzymes involved in the biogeochemical cycles of carbon, nitrogen, phosphorous and sulphur, respectively, as well as microbial biomass C were measured. Results of this study seem to indicate that a great variability exists among the farms. A clear evidence is that the control samples, not subjected to intensive farming, always showed better values of chemical properties and higher values of enzymatic activity and microbial biomass to indicate a negative effect of intensive agriculture practices on soil quality and fertility in studied areas. Data confirm that enzymatic activities and microbial biomass can be considered valid and sensitive indicators of soil quality.

  5. Spatial distribution of soil organic carbon stocks in France

    NASA Astrophysics Data System (ADS)

    Martin, M. P.; Wattenbach, M.; Smith, P.; Meersmans, J.; Jolivet, C.; Boulonne, L.; Arrouays, D.

    2010-11-01

    Soil organic carbon plays a major role in the global carbon budget, and can act as a source or a sink of atmospheric carbon, whereby it can influence the course of climate change. Changes in soil organic soil stocks (SOCS) are now taken into account in international negotiations regarding climate change. Consequently, developing sampling schemes and models for estimating the spatial distribution of SOCS is a priority. The French soil monitoring network has been established on a 16 km × 16 km grid and the first sampling campaign has recently been completed, providing circa 2200 measurements of stocks of soil organic carbon, obtained through an in situ composite sampling, uniformly distributed over the French territory. We calibrated a boosted regression tree model on the observed stocks, modelling SOCS as a function of other variables such as climatic parameters, vegetation net primary productivity, soil properties and land use. The calibrated model was evaluated through cross-validation and eventually used for estimating SOCS for the whole of metropolitan France. Two other models were calibrated on forest and agricultural soils separately, in order to assess more precisely the influence of pedo-climatic variables on soil organic carbon for such soils. The boosted regression tree model showed good predictive ability, and enabled quantification of relationships between SOCS and pedo-climatic variables (plus their interactions) over the French territory. These relationship strongly depended on the land use, and more specifically differed between forest soils and cultivated soil. The total estimate of SOCS in France was 3.260 ± 0.872 PgC for the first 30 cm. It was compared to another estimate, based on the previously published European soil organic carbon and bulk density maps, of 5.303 PgC. We demonstrate that the present estimate might better represent the actual SOCS distributions of France, and consequently that the previously published approach at the European

  6. Effects of organic carbon sequestration strategies on soil enzymatic activities

    NASA Astrophysics Data System (ADS)

    Puglisi, E.; Suciu, N.; Botteri, L.; Ferrari, T.; Coppolecchia, D.; Trevisan, M.; Piccolo, A.

    2009-04-01

    Greenhouse gases emissions can be counterbalanced with proper agronomical strategies aimed at sequestering carbon in soils. These strategies must be tested not only for their ability in reducing carbon dioxide emissions, but also for their impact on soil quality: enzymatic activities are related to main soil ecological quality, and can be used as early and sensitive indicators of alteration events. Three different strategies for soil carbon sequestration were studied: minimum tillage, protection of biodegradable organic fraction by compost amendment and oxidative polimerization of soil organic matter catalyzed by biometic porfirins. All strategies were compared with a traditional agricultural management based on tillage and mineral fertilization. Experiments were carried out in three Italian soils from different pedo-climatic regions located respectively in Piacenza, Turin and Naples and cultivated with maize or wheat. Soil samples were taken for three consecutive years after harvest and analyzed for their content in phosphates, ß-glucosidase, urease and invertase. An alteration index based on these enzymatic activities levels was applied as well. The biomimetic porfirin application didn't cause changes in enzymatic activities compared to the control at any treatment or location. Enzymatic activities were generally higher in the minimum tillage and compost treatment, while differences between location and date of samplings were limited. Application of the soil alteration index based on enzymatic activities showed that soils treated with compost or subjected to minimum tillage generally have a higher biological quality. The work confirms the environmental sustainability of the carbon sequestering agronomical practices studied.

  7. Ectomycorrhizal fungi slow soil carbon cycling.

    PubMed

    Averill, Colin; Hawkes, Christine V

    2016-08-01

    Respiration of soil organic carbon is one of the largest fluxes of CO2 on earth. Understanding the processes that regulate soil respiration is critical for predicting future climate. Recent work has suggested that soil carbon respiration may be reduced by competition for nitrogen between symbiotic ectomycorrhizal fungi that associate with plant roots and free-living microbial decomposers, which is consistent with increased soil carbon storage in ectomycorrhizal ecosystems globally. However, experimental tests of the mycorrhizal competition hypothesis are lacking. Here we show that ectomycorrhizal roots and hyphae decrease soil carbon respiration rates by up to 67% under field conditions in two separate field exclusion experiments, and this likely occurs via competition for soil nitrogen, an effect larger than 2 °C soil warming. These findings support mycorrhizal competition for nitrogen as an independent driver of soil carbon balance and demonstrate the need to understand microbial community interactions to predict ecosystem feedbacks to global climate. PMID:27335203

  8. Ecological value of soil carbon management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Management of soil carbon is critical to the climate change debate, as well as to the long-term productivity and ecosystem resilience of the biosphere. Soil organic carbon is a key ecosystem property that indicates inherent productivity of land, controls soil biological functioning and diversity, r...

  9. Evolution of black carbon properties in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black carbon deposited in soil from natural or deliberate wildfires and engineered black carbon products (biochar) intentionally added to soil are known to have significant effects on soil biogeochemical processes and in many cases to influence the yield and quality of crops and to enhance the abili...

  10. Ecological controls over global soil carbon storage

    SciTech Connect

    Schimel, D.S.

    1995-09-01

    Globally, soil carbon comprises about 2/3 of terrestrial carbon storage. Soil carbon is thus an important reservoir of carbon, but also influences the responses of ecosystems to change by controlling many aspects of nutrient cycling. While broad-scale patterns of soil carbon accumulation can be explained in terms of climatic and biome distributions, many ecological processes also influence the storage and turnover of carbon in soils. I will present a synthesis of information from field studies, model experiments and global data bases on factors controlling the turnover and storage of soil carbon. First, I will review a series of studies showing links between vegetation change (successional and invasions) and soil carbon. Then I will review model analyses of the sensitivity of soil carbon to climatic and ecological changes. Results show that soil carbon storage is broadly sensitive to climate but greatly influenced by the allocation of detritus between resistant (lignaceous and woody) and more labile forms, and that biotic changes that affect allocation, affect soil carbon substantially at regionally and perhaps global scales.

  11. Implications of Using Thermal Desorption to Remediate Contaminated Agricultural Soil: Physical Characteristics and Hydraulic Processes.

    PubMed

    O'Brien, Peter L; DeSutter, Thomas M; Casey, Francis X M; Derby, Nathan E; Wick, Abbey F

    2016-07-01

    Given the recent increase in crude oil production in regions with predominantly agricultural economies, the determination of methods that remediate oil contamination and allow for the land to return to crop production is increasingly relevant. Ex situ thermal desorption (TD) is a technique used to remediate crude oil pollution that allows for reuse of treated soil, but the properties of that treated soil are unknown. The objectives of this research were to characterize TD-treated soil and to describe implications in using TD to remediate agricultural soil. Native, noncontaminated topsoil and subsoil adjacent to an active remediation site were separately subjected to TD treatment at 350°C. Soil physical characteristics and hydraulic processes associated with agricultural productivity were assessed in the TD-treated samples and compared with untreated samples. Soil organic carbon decreased more than 25% in both the TD-treated topsoil and the subsoil, and total aggregation decreased by 20% in the topsoil but was unaffected in the subsoil. The alteration in these physical characteristics explains a 400% increase in saturated hydraulic conductivity in treated samples as well as a decrease in water retention at both field capacity and permanent wilting point. The changes in soil properties identified in this study suggest that TD-treated soils may still be suitable for sustaining vegetation, although likely at a slightly diminished capacity when directly compared with untreated soils. PMID:27380094

  12. Implications of Using Thermal Desorption to Remediate Contaminated Agricultural Soil: Physical Characteristics and Hydraulic Processes.

    PubMed

    O'Brien, Peter L; DeSutter, Thomas M; Casey, Francis X M; Derby, Nathan E; Wick, Abbey F

    2016-07-01

    Given the recent increase in crude oil production in regions with predominantly agricultural economies, the determination of methods that remediate oil contamination and allow for the land to return to crop production is increasingly relevant. Ex situ thermal desorption (TD) is a technique used to remediate crude oil pollution that allows for reuse of treated soil, but the properties of that treated soil are unknown. The objectives of this research were to characterize TD-treated soil and to describe implications in using TD to remediate agricultural soil. Native, noncontaminated topsoil and subsoil adjacent to an active remediation site were separately subjected to TD treatment at 350°C. Soil physical characteristics and hydraulic processes associated with agricultural productivity were assessed in the TD-treated samples and compared with untreated samples. Soil organic carbon decreased more than 25% in both the TD-treated topsoil and the subsoil, and total aggregation decreased by 20% in the topsoil but was unaffected in the subsoil. The alteration in these physical characteristics explains a 400% increase in saturated hydraulic conductivity in treated samples as well as a decrease in water retention at both field capacity and permanent wilting point. The changes in soil properties identified in this study suggest that TD-treated soils may still be suitable for sustaining vegetation, although likely at a slightly diminished capacity when directly compared with untreated soils.

  13. Irrigated agriculture and soil salinization in the Maltese islands.

    PubMed

    Vella, Sonya J; Camilleri, Sharlo

    2003-08-01

    In the Maltese islands, soil is one of the most threatened natural resources, being continuously exposed to a multitude of climatic, environmental, and man-induced impacts. The changes in agricultural practices as well as increases in urban development have intensified environmental problems and have accentuated the pressures on agricultural land and fragile semi-natural ecosystems. Between 1956 and 2001, the total agricultural land declined from 20,433 ha to 10,713 ha, however, during the same period, the irrigated land as a percentage of total agricultural land increased from 3.9% to 10.7%. The poor quality of irrigation water sources, and the supply of treated sewage effluent with a high level of salts, contribute to a significant salt input. The extent of salt-affected soils in the Maltese islands is not well-documented, however, field observations and technical reports indicate that soil salinity is a potential constraint for agricultural production. This article gives a comparative review of the salinity status of soils in three case study areas in Malta, the agricultural dryland at Ghammieri, the intensively cultivated irrigated valley of Pwales, and the agricultural land irrigated with treated sewage effluent of the Sant Antnin Sewage Treatment Plant in the South-East of Malta. This analysis is provided in the context of the environmental impact of irrigation on soil quality in the Maltese islands.

  14. Soil Organic Carbon Input from Urban Turfgrasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Turfgrass is a major vegetation type in the urban and suburban environment. Management practices such as species selection, irrigation, and mowing may affect carbon input and storage in these systems. Research was conducted to determine the rate of soil organic carbon (SOC) changes, soil carbon sequ...

  15. Soil Organic Carbon Input from Urban Turfgrasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Turfgrass is a major vegetation type in the urban and suburban environment. Management practices such as species selection, irrigation, and mowing may affect carbon (C) input and storage in these systems. Research was conducted to determine the rate of soil organic carbon (SOC) changes, soil carbon ...

  16. Biological indicators of soil quality and soil organic matter characteristics in an agricultural management continuum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Relationships among biological indicators of soil quality and soil organic matter characteristics in a claypan soil were evaluated across a continuum of long-term agricultural practices in Missouri, USA. In addition to chemical and physical soil quality indicators, dehydrogenase and phenol oxidase a...

  17. Towards an Integrated Methodology for Measuring and Monitoring Soil Carbon at Regional Scales (Invited)

    NASA Astrophysics Data System (ADS)

    Izaurralde, R. C.

    2009-12-01

    Soil carbon accounts for the second largest stock of the biosphere. Agricultural soils contain an important fraction of the total stock and depending on management and environmental conditions can behave as sources or sinks of atmospheric carbon dioxide. Implementation of improved agricultural practices and restoration of land productivity can lead to soil carbon sequestration and therefore contribute not only to mitigate climate change but also satisfy the food, fiber, and bioenergy demands of future generations. Further, increasing soil carbon and, thus, soil organic matter, would improve the adaptive capacity of agricultural soils to withstand or attenuate the negative effects of climate change. At the site scale, soil carbon—at times with great precision—has been measured, monitored, and modeled often using long-term observations. At the regional level, however, soil carbon changes are usually modeled using accounting methods, biogeochemical simulations, and remotely sensed data. These procedures usually generate uncertainty in the estimation of soil carbon change due to the lack of local observations, spatial or temporal scales that these studies are conducted, and lack of information concerning the kinetic status of the soil carbon pools. Recent advances in techniques to measure and map soil carbon, conduct spatial simulations of soil carbon, and remotely sense biophysical variables such as yield, net primary productivity, residue cover, and soil moisture promise to enhance our capability to develop an integrated methodology to measure and monitor soil carbon changes at regional scales. Implementation and testing of this type of integrated technologies will be crucial for building robust soil carbon accounting systems be these of regional or national nature.

  18. Soil Organic Carbon Stocks in Depositional Landscapes of Bavaria

    NASA Astrophysics Data System (ADS)

    Kriegs, Stefanie; Schwindt, Daniel; Völkel, Jörg; Kögel-Knabner, Ingrid

    2016-04-01

    Erosion leads to redistribution and accumulation of soil organic matter (SOM) within agricultural landscapes. These fluvic and colluvic deposits are characterized by a highly diverse vertical structure and can contain high amounts of soil organic carbon (SOC) over the whole soil profile. Depositional landscapes are therefore not only productive sites for agricultural use but also influence carbon dynamics which is of great interest with regard on the recent climate change debate. The aim of our study is to elucidate the spatial distribution of organic carbon stocks, as well as its depth function and the role of these landscapes as a reservoir for SOM. Therefore we compare two representative depositional landscapes in Bavaria composed of different parent materials (carbonate vs. granitic). We hypothesize that the soils associated with different depositional processes (fluvial vs. colluvial) differ in SOC contents and stocks, also because of different hydromorphic regimes in fluvic versus colluvic soil profiles. Sampling sites are located in the Alpine Foreland (quaternary moraines with carbonatic parent material) and the foothills of the Bavarian Forest (Granite with Loess) with the main soil types Fluvisols, Gleysols and Luvisols. At both sites we sampled twelve soil profiles up to 150 cm depth, six in the floodplain and six along a vertical slope transect. We took undisturbed soil samples from each horizon and analyzed them for bulk density, total Carbon (OC and IC) and total Nitrogen (N) concentrations. This approach allows to calculate total OC contents and OC stocks and to investigate vertical and horizontal distribution of OC stocks. It will also reveal differences in OC stocks due to the location of the soil profile in fluvic or colluvic deposition scenarios.

  19. Changes in Soil Chemistry and Agricultural Return Flow in an Integrated Seawater Agriculture System (ISAS) Demonstration in Abu Dhabi

    NASA Astrophysics Data System (ADS)

    Ning, Q.; Matiin, W. A.; Ahmad, F.

    2012-12-01

    Growing halophytes using Integrated Seawater Agriculture Systems (ISAS) offers a sustainable solution for the generation of biomass feedstock for carbon neutral biofuels - halophytes do not enter the foodchain and they do not compete with food-crops for natural resources. A field demonstration of ISAS in the coastal regions of Abu Dhabi, UAE, scheduled to start in 2013, will likely face a number of region-specific challenges not encountered in past demonstrations of ISAS at coastal locations in Mexico and Eritrea. The arid climate, unique soil chemistry (evaporite deposits, especially gypsum), and hypersaline coastal hydrogeology of Abu Dhabi will affect long-term halophyte agricultural productivity when Arabian Gulf seawater is applied to coastal soils as part of ISAS. Therefore, the changes in irrigation return flow quality and soil chemistry must be monitored closely over time to establish transient salt and water balances in order to assess the sustainability of ISAS in the region. As an initial phase of the ISAS demonstration project, numerical modeling of different seawater loadings onto coastal soils was conducted to estimate the chemical characteristics of soil and the irrigation return flow over time. These modeling results will be validated with field monitoring data upon completion of one year of ISAS operation. The results from this study could be used to (i) determine the optimal saline water loading that the soils at the ISAS site can tolerate, (ii) potential for sodicity of the soil with saline water application, (iii) impacts of land application of saline water on underlying coastal groundwater, and (iv) develop strategies to control soil water activities in favor of halophyte agricultural productivity.

  20. Distribution of soil organic carbon in the conterminous United States

    USGS Publications Warehouse

    Bliss, Norman B.; Waltman, Sharon W.; West, Larry T.; Neale, Anne; Mehaffey, Megan; Hartemink, Alfred E.; McSweeney, Kevin M.

    2014-01-01

    The U.S. Soil Survey Geographic (SSURGO) database provides detailed soil mapping for most of the conterminous United States (CONUS). These data have been used to formulate estimates of soil carbon stocks, and have been useful for environmental models, including plant productivity models, hydrologic models, and ecological models for studies of greenhouse gas exchange. The data were compiled by the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS) from 1:24,000-scale or 1:12,000-scale maps. It was found that the total soil organic carbon stock in CONUS to 1 m depth is 57 Pg C and for the total profile is 73 Pg C, as estimated from SSURGO with data gaps filled from the 1:250,000-scale Digital General Soil Map. We explore the non-linear distribution of soil carbon on the landscape and with depth in the soil, and the implications for sampling strategies that result from the observed soil carbon variability.

  1. Environmental analyse of soil organic carbon stock changes in Slovakia

    NASA Astrophysics Data System (ADS)

    Koco, Š.; Barančíková, G.; Skalský, R.; Tarasovičová, Z.; Gutteková, M.; Halas, J.; Makovníková, J.; Novákova, M.

    2012-04-01

    The content and quality of soil organic matter is one of the basic soil parameters on which soil production functioning depends as well as it is active in non production soil functions like an ecological one especially. Morphologic segmentation of Slovakia has significant influence of structure in using agricultural soil in specific areas of our territory. Also social changes of early 90´s of 20´th century made their impact on change of using of agricultural soil (transformation from large farms to smaller ones, decreasing the number of livestock). This research is studying changes of development of soil organic carbon stock (SOC) in agricultural soil of Slovakia as results of climatic as well as social and political changes which influenced agricultury since last 40 years. The main goal of this research is an analysis of soil organic carbon stock since 1970 until now at specific agroclimatic regions of Slovakia and statistic analysis of relation between modelled data of SOC stock and soil quality index value. Changes of SOC stock were evaluated on the basis SOC content modeling using RothC-26.3 model. From modeling of SOC stock results the outcome is that in that time the soil organic carbon stock was growing until middle 90´s years of 20´th century with the highest value in 1994. Since that year until new millennium SOC stock is slightly decreasing. After 2000 has slightly increased SOC stock so far. According to soil management SOC stock development on arable land is similar to overall evolution. In case of grasslands after slight growth of SOC stock since 1990 the stock is in decline. This development is result of transformational changes after 1989 which were specific at decreasing amount of organic carbon input from organic manure at grassland areas especially. At warmer agroclimatic regions where mollic fluvisols and chernozems are present and where are soils with good quality and steady soil organic matter (SOM) the amount of SOC in monitored time is

  2. Soil Type Identification Using Remotely Sensed Data for Agricultural Purpose

    NASA Astrophysics Data System (ADS)

    Jiji, G. Wiselin; Nadar, Pallavi

    2016-09-01

    Soil assessment plays important role in making decisions for Agriculture. In this paper, an approach by integrating the image processing and pattern recognition techniques to find the type of soil has been presented. The soil from the area of interest is selected and soil indices are extracted as features. Indexing technique is used for faster retrieval. The efficiency of the proposed system is proved using sensitivity, specificity, precision and recall. Our empirical evaluation has a superior retrieval performance over the performance of other works. This work is of great use to the farmers, who need to identify their field's soil type.

  3. Urban soils: properties for utilitzation for green infrastructure and urban agriculture

    NASA Astrophysics Data System (ADS)

    Shanskiy, Merrit; Krebstein, Kadri

    2015-04-01

    The human influenced soils in urban areas are of prime importance to human populations. Also, it is becoming a trend that there is large increase in reclaimed lands and new users for old industrial areas. Very often the urban soils are heavily modified by different anthropogenic factors. Therefore, it makes it essential to collect the data and knowledge of urban soils in order to understand better how such soils can be managed, rehabilitated or reconditioned to support green infrastructure or urban agriculture. Although the soil organic carbon (SOC) is the largest carbon stock in terrestrial ecosystems and the carbon sequestration is a widely accepted soil function there is still few studies mapping the carbon stocks in urban areas using digital soil mapping techniques. For urban land-use planning and decision making in a process of green infrastructure sustainable development it is in major importance. The urban soils are often lacking sufficient amount of organic matter but they are degraded (compacted, builded, contaminated by construction debris, graded) making them unsuitable as a growing medium. Therefore, the use of certain green infrastructure practices and the development of urban agriculture can be challenging in an urban environment. The issue of assessing soil quality becomes two-fold: the health of the soil as a growing medium needs to be addressed as well as the possible contamination that may be present. Knowing the development history of a parcel is key to determining what type of soil testing should be done, if any, prior to redevelopment or reuse. For current, pilot scale study the soil sampling was carried out in Tartu, Estonia. The different microenvironments were determined inside of urban areas. Soils were collected from such a microenvironments as urban garden areas, parks, other green infrastructure elements. The soils were analyzed for main agrochemical and physical properties at the Estonian University of Life Sciences, laboratory of the

  4. Enhancing soil sorption capacity of an agricultural soil by addition of three different organic wastes.

    PubMed

    Rojas, Raquel; Morillo, José; Usero, José; Delgado-Moreno, Laura; Gan, Jay

    2013-08-01

    This study evaluated the ability of three unmodified organic residues (composted sewage sludge, RO1; chicken manure, RO2; and a residue from olive oil production called 'orujillo', RO3) and a soil to sorb six pesticides (atrazine, lindane, alachlor, chlorpyrifos, chlorfenvinphos and endosulfan sulfate) and thereby explored the potential environmental value of these organic residues for mitigating pesticide pollution in agricultural production and removing contaminants from wastewater. Pesticide determination was carried out using gas chromatography coupled with mass spectrometry. Adsorption data were analyzed by the Langmuir and Freundlich adsorption approaches. Experimental results showed that the Freundlich isotherm model best described the adsorption process and that Kf values increased with an increase in organic matter (OM) content of the amended soil. The order of adsorption of pesticides on soils was: chlorpyrifos≥endosulfan sulfate>chlorfenvinphos≥lindane>alachlor≥atrazine. The sorption was greater for the most hydrophobic compounds and lower for the most polar ones, as corroborated by a negative correlation between Kf values and solubility. Sorption increased with an increase in organic matter. Sorption capacity was positively correlated with the organic carbon (OC) content. The organic amendment showing the maximum sorption capacity was RO3 in all cases, except for chlorfenvinphos, in which it was RO2. The order of adsorption capacity of the amendments depended on the pesticide and the organic dosage. In the case of the 10% amendment the order was RO3>RO2>RO1>soil, except for chlorfenvinphos, in which it was RO2>RO3>RO1>soil, and atrazine, where RO2 and RO3 amendments had the same effect on the soil sorption capacity (RO2≥RO3>RO1>soil).

  5. Carbon dynamics within agricultural and native sites in the loess region of Western lowa

    USGS Publications Warehouse

    Manies, K.L.; Harden, J.W.; Kramer, L.; Parton, W.J.

    2001-01-01

    In order to quantify the historical changes in carbon storage that result from agricultural conversion, this study compared the carbon dynamics of two sites in the loess region of Iowa: a native prairie and a cropland. Field data were obtained to determine present-day carbon storage and its variability within a landscape (a stable ridgetop vs. eroding upper-midslope vs. depositional lower slope). Models were used to recreate the historical carbon budget of these sites and determine the cropland's potential to be a net CO2 source or sink, relative to the atmosphere. Regardless of slope position, the cropland site contains approximately half the amount of carbon as prairie. Variability in soil carbon storage within a site as a consequence of slope position is as large or larger (variations of 200-300%) than temporal variation (???200% at all slope positions). The most extreme difference in soil carbon storage between the cropland and prairie sites is found in the soil at the upper-midslope, which is the area of greatest erosion. The models estimate that 93-172% of the carbon in the original topsoil has been lost from the cropland's eroding midslope. Much of this carbon is derived from deeper soil horizons. Either a small sink or strong source of carbon to the atmosphere is created, depending on the fate of the eroded sediment and its associated carbon.

  6. Soil Organic Carbon Loss: An Overlooked Factor in the Carbon Sequestration Potential of Enhanced Mineral Weathering

    NASA Astrophysics Data System (ADS)

    Dietzen, Christiana; Harrison, Robert

    2016-04-01

    Weathering of silicate minerals regulates the global carbon cycle on geologic timescales. Several authors have proposed that applying finely ground silicate minerals to soils, where organic acids would enhance the rate of weathering, could increase carbon uptake and mitigate anthropogenic CO2 emissions. Silicate minerals such as olivine could replace lime, which is commonly used to remediate soil acidification, thereby sequestering CO2 while achieving the same increase in soil pH. However, the effect of adding this material on soil organic matter, the largest terrestrial pool of carbon, has yet to be considered. Microbial biomass and respiration have been observed to increase with decreasing acidity, but it is unclear how long the effect lasts. If the addition of silicate minerals promotes the loss of soil organic carbon through decomposition, it could significantly reduce the efficiency of this process or even create a net carbon source. However, it is possible that this initial flush of microbial activity may be compensated for by additional organic matter inputs to soil pools due to increases in plant productivity under less acidic conditions. This study aimed to examine the effects of olivine amendments on soil CO2 flux. A liming treatment representative of typical agricultural practices was also included for comparison. Samples from two highly acidic soils were split into groups amended with olivine or lime and a control group. These samples were incubated at 22°C and constant soil moisture in jars with airtight septa lids. Gas samples were extracted periodically over the course of 2 months and change in headspace CO2 concentration was determined. The effects of enhanced mineral weathering on soil organic matter have yet to be addressed by those promoting this method of carbon sequestration. This project provides the first data on the potential effects of enhanced mineral weathering in the soil environment on soil organic carbon pools.

  7. Underestimation of boreal soil carbon stocks by mathematical soil carbon models linked to soil nutrient status

    NASA Astrophysics Data System (ADS)

    Ťupek, Boris; Ortiz, Carina A.; Hashimoto, Shoji; Stendahl, Johan; Dahlgren, Jonas; Karltun, Erik; Lehtonen, Aleksi

    2016-08-01

    Inaccurate estimate of the largest terrestrial carbon pool, soil organic carbon (SOC) stock, is the major source of uncertainty in simulating feedback of climate warming on ecosystem-atmosphere carbon dioxide exchange by process-based ecosystem and soil carbon models. Although the models need to simplify complex environmental processes of soil carbon sequestration, in a large mosaic of environments a missing key driver could lead to a modeling bias in predictions of SOC stock change.We aimed to evaluate SOC stock estimates of process-based models (Yasso07, Q, and CENTURY soil sub-model v4) against a massive Swedish forest soil inventory data set (3230 samples) organized by a recursive partitioning method into distinct soil groups with underlying SOC stock development linked to physicochemical conditions.For two-thirds of measurements all models predicted accurate SOC stock levels regardless of the detail of input data, e.g., whether they ignored or included soil properties. However, in fertile sites with high N deposition, high cation exchange capacity, or moderately increased soil water content, Yasso07 and Q models underestimated SOC stocks. In comparison to Yasso07 and Q, accounting for the site-specific soil characteristics (e. g. clay content and topsoil mineral N) by CENTURY improved SOC stock estimates for sites with high clay content, but not for sites with high N deposition.Our analysis suggested that the soils with poorly predicted SOC stocks, as characterized by the high nutrient status and well-sorted parent material, indeed have had other predominant drivers of SOC stabilization lacking in the models, presumably the mycorrhizal organic uptake and organo-mineral stabilization processes. Our results imply that the role of soil nutrient status as regulator of organic matter mineralization has to be re-evaluated, since correct SOC stocks are decisive for predicting future SOC change and soil CO2 efflux.

  8. Spatial distribution of soil organic carbon stocks in France

    NASA Astrophysics Data System (ADS)

    Martin, M. P.; Wattenbach, M.; Smith, P.; Meersmans, J.; Jolivet, C.; Boulonne, L.; Arrouays, D.

    2011-05-01

    Soil organic carbon plays a major role in the global carbon budget, and can act as a source or a sink of atmospheric carbon, thereby possibly influencing the course of climate change. Changes in soil organic carbon (SOC) stocks are now taken into account in international negotiations regarding climate change. Consequently, developing sampling schemes and models for estimating the spatial distribution of SOC stocks is a priority. The French soil monitoring network has been established on a 16 km × 16 km grid and the first sampling campaign has recently been completed, providing around 2200 measurements of stocks of soil organic carbon, obtained through an in situ composite sampling, uniformly distributed over the French territory. We calibrated a boosted regression tree model on the observed stocks, modelling SOC stocks as a function of other variables such as climatic parameters, vegetation net primary productivity, soil properties and land use. The calibrated model was evaluated through cross-validation and eventually used for estimating SOC stocks for mainland France. Two other models were calibrated on forest and agricultural soils separately, in order to assess more precisely the influence of pedo-climatic variables on SOC for such soils. The boosted regression tree model showed good predictive ability, and enabled quantification of relationships between SOC stocks and pedo-climatic variables (plus their interactions) over the French territory. These relationships strongly depended on the land use, and more specifically, differed between forest soils and cultivated soil. The total estimate of SOC stocks in France was 3.260 ± 0.872 PgC for the first 30 cm. It was compared to another estimate, based on the previously published European soil organic carbon and bulk density maps, of 5.303 PgC. We demonstrate that the present estimate might better represent the actual SOC stock distributions of France, and consequently that the previously published approach at the

  9. Soil warming, carbon-nitrogen interactions, and forest carbon budgets.

    PubMed

    Melillo, Jerry M; Butler, Sarah; Johnson, Jennifer; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-Mei; Tang, Jim

    2011-06-01

    Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon-nitrogen interactions in atmosphere-ocean-land earth system models to accurately simulate land feedbacks to the climate system.

  10. Soil CO2 emissions in terms of irrigation management in an agricultural soil

    NASA Astrophysics Data System (ADS)

    Zornoza, Raúl; Acosta, José A.; María de la Rosa, José; Faz, Ángel; Domingo, Rafael; Pérez-Pastor, Alejandro; Ángeles Muñoz, María

    2014-05-01

    Irrigation water restrictions in the Mediterranean area are reaching worrying proportions and represent a serious threat to traditional crops and encourage the movement of people who choose to work in other activities. This situation has created a growing interest in water conservation, particularly among practitioners of irrigated agriculture, the main recipient of water resources (>80%). For these and other reasons, the scientific and technical irrigation scheduling of water use to maintain and even improve harvest yield and quality has been and will remain a major challenge for irrigated agriculture. Apart from environmental and economic benefits by water savings, deficit irrigation may contribute to reduce soil CO2 emissions and enhance C sequestration in soils. The reduction of soil moisture levels decreases microbial activity, with the resulting slowing down of organic matter mineralization. Besides, the application of water by irrigation may increment the precipitation rate of carbonates, favoring the storage of C, but depending on the source of calcium or bicarbonate, the net reaction can be either storage or release of C. Thus, the objective of this study was to assess if deficit irrigation, besides contributing to water savings, can reduce soil CO2 emissions and favor the accumulation of C in soils in stable forms. The experiment was carried out along 2012 in a commercial orchard from southeast Spain cultivated with nectarine trees (Prunus persica cv. 'Viowhite'). The irrigation system was drip localized. Three irrigation treatments were assayed: a control (CT), irrigated to satisfy the total hydric needs of the crop; a first deficit irrigation (DI1), irrigated as CT except for postharvest period (16 June - 28 October) were 50% of CT was applied; and a second deficit irrigation (DI2), irrigated as DI1, except for two periods in which irrigation was suppressed (16 June-6 July and 21 July-17 August). Each treatment was setup in triplicate, randomly

  11. Soil biota and agriculture production in conventional and organic farming

    NASA Astrophysics Data System (ADS)

    Schrama, Maarten; de Haan, Joj; Carvalho, Sabrina; Kroonen, Mark; Verstegen, Harry; Van der Putten, Wim

    2015-04-01

    Sustainable food production for a growing world population requires a healthy soil that can buffer environmental extremes and minimize its losses. There are currently two views on how to achieve this: by intensifying conventional agriculture or by developing organically based agriculture. It has been established that yields of conventional agriculture can be 20% higher than of organic agriculture. However, high yields of intensified conventional agriculture trade off with loss of soil biodiversity, leaching of nutrients, and other unwanted ecosystem dis-services. One of the key explanations for the loss of nutrients and GHG from intensive agriculture is that it results in high dynamics of nutrient losses, and policy has aimed at reducing temporal variation. However, little is known about how different agricultural practices affect spatial variation, and it is unknown how soil fauna acts this. In this study we compare the spatial and temporal variation of physical, chemical and biological parameters in a long term (13-year) field experiment with two conventional farming systems (low and medium organic matter input) and one organic farming system (high organic matter input) and we evaluate the impact on ecosystem services that these farming systems provide. Soil chemical (N availability, N mineralization, pH) and soil biological parameters (nematode abundance, bacterial and fungal biomass) show considerably higher spatial variation under conventional farming than under organic farming. Higher variation in soil chemical and biological parameters coincides with the presence of 'leaky' spots (high nitrate leaching) in conventional farming systems, which shift unpredictably over the course of one season. Although variation in soil physical factors (soil organic matter, soil aggregation, soil moisture) was similar between treatments, but averages were higher under organic farming, indicating more buffered conditions for nutrient cycling. All these changes coincide with

  12. Concentrations, loads, and yields of organic carbon in streams of agricultural watersheds

    USGS Publications Warehouse

    Kronholm, Scott; Capel, Paul

    2012-01-01

    Carbon is cycled to and from large reservoirs in the atmosphere, on land, and in the ocean. Movement of organic carbon from the terrestrial reservoir to the ocean plays an important role in the global cycling of carbon. The transition from natural to agricultural vegetation can change the storage and movement of organic carbon in and from a watershed. Samples were collected from 13 streams located in hydrologically and agriculturally diverse watersheds, to better understand the variability in the concentrations and loads of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the streams, and the variability in watershed yields. The overall annual median concentrations of DOC and POC were 4.9 (range: 2.1–6.8) and 1.1 (range: 0.4–3.8) mg C L−1, respectively. The mean DOC watershed yield (± SE) was 25 ± 6.8 kg C ha−1 yr−1. The yields of DOC from these agricultural watersheds were not substantially different than the DOC yield from naturally vegetated watersheds in equivalent biomes, but were at the low end of the range for most biomes. Total organic carbon (DOC + POC) annually exported from the agricultural watersheds was found to average 0.03% of the organic carbon that is contained in the labile plant matter and top 1 m of soil in the watershed. Since the total organic carbon exported from agricultural watersheds is a relatively small portion of the sequestered carbon within the watershed, there is the great potential to store additional carbon in plants and soils of the watershed, offsetting some anthropogenic CO2 emissions.

  13. Prediction of soil organic carbon concentration and soil bulk density of mineral soils for soil organic carbon stock estimation

    NASA Astrophysics Data System (ADS)

    Putku, Elsa; Astover, Alar; Ritz, Christian

    2016-04-01

    Soil monitoring networks provide a powerful base for estimating and predicting nation's soil status in many aspects. The datasets of soil monitoring are often hierarchically structured demanding sophisticated data analyzing methods. The National Soil Monitoring of Estonia was based on a hierarchical data sampling scheme as each of the monitoring site was divided into four transects with 10 sampling points on each transect. We hypothesized that the hierarchical structure in Estonian Soil Monitoring network data requires a multi-level mixed model approach to achieve good prediction accuracy of soil properties. We used this database to predict soil bulk density and soil organic carbon concentration of mineral soils in arable land using different statistical methods: median approach, linear regression and mixed model; additionally, random forests for SOC concentration. We compared the prediction results and selected the model with the best prediction accuracy to estimate soil organic carbon stock. The mixed model approach achieved the best prediction accuracy in both soil organic carbon (RMSE 0.22%) and bulk density (RMSE 0.09 g cm-3) prediction. Other considered methods under- or overestimated higher and lower values of soil parameters. Thus, using these predictions we calculated the soil organic carbon stock of mineral arable soils and applied the model to a specific case of Tartu County in Estonia. Average estimated SOC stock of Tartu County is 54.8 t C ha-1 and total topsoil SOC stock 1.8 Tg in humus horizon.

  14. Ancient Agricultural Terraces and the Soil Erosion Paradox

    NASA Astrophysics Data System (ADS)

    Brown, Tony

    2015-04-01

    Geoarchaeology lies at the heart of debates about societal stability and change. Geomorphological research has been used as a foundation for simplistic models of resource depletion based almost entirely on the comparison of soil erosion rates with long-term so- called 'geological' rates. However, the neo-catastrophic collapse of complex agricultural societies is rare, and where it is convincing demonstrated it is even more rarely monocausal. Indeed many societies appear to have continued agricultural exploitation of climatically marginal lands for far longer than soil depletion estimates would forecast. One reason may be that this soil depletion approach has grossly simplified soil creation through weathering, and neglected how past agriculture also affected the soil creation rate (especially on some lithologies) and how soil was conserved (terraces) and utilised even after transport. However, we now have we know have some potentially valuable new tools, including mineral magnetics and cosmogenic nuclides, which can be used to estimate changing soil weathering rates. This approach will be discussed with examples from both the temperate and Mediterranean climatic zones and in relation to causative models of change in complex agricultural societies.

  15. Phenylurea herbicide sorption to biochars and agricultural soil

    PubMed Central

    WANG, DAOYUAN; MUKOME, FUNGAI N. D.; YAN, DENGHUA; WANG, HAO; SCOW, KATE M.; PARIKH, SANJAI J.

    2016-01-01

    Biochar is increasingly been used as a soil amendment to improve water holding capacity, reduce nutrient leaching, increase soil pH and also as a means to reduce contamination through sorption of heavy metals or organic pollutants. The sorption behavior of three phenylurea herbicides (monuron, diuron, linuron) on five biochars (Enhanced Biochar, Hog Waste, Turkey Litter, Walnut Shell and Wood Feedstock) and an agricultural soil (Yolo silt loam) was investigated using a batch equilibration method. Sorption isotherms of herbicides to biochars were well described by the Freundlich model (R2 = 0.93 -- 0.97). The adsorption KF values ranged from 6.94 to 1306.95 mg kg−1 and indicated the sorption of herbicides in the biochars and Yolo soil was in the sequence of linuron > diuron > monuron and walnut shell biochar > wood feedstock biochar > turkey litter biochar > enhanced biochar > hog waste biochar > Yolo soil. These data show that sorption of herbicides to biochar can have both positive (reduced off-site transport) and negative (reduced herbicide efficacy) implications and specific biochar properties, such as H/C ratio and surface area, should be considered together with soil type, agriculture chemical and climate condition in biochar application to agricultural soil to optimize the system for both agricultural and environmental benefits. PMID:26065514

  16. Phenylurea herbicide sorption to biochars and agricultural soil.

    PubMed

    Wang, Daoyuan; Mukome, Fungai N D; Yan, Denghua; Wang, Hao; Scow, Kate M; Parikh, Sanjai J

    2015-01-01

    Biochar is increasingly been used as a soil amendment to improve water-holding capacity, reduce nutrient leaching, increase soil pH, and also as a means to reduce contamination through sorption of heavy metals or organic pollutants. The sorption behavior of three phenylurea herbicides (monuron, diuron and linuron) on five biochars (Enhanced Biochar, Hog Waste, Turkey Litter, Walnut Shell and Wood Feedstock) and an agricultural soil (Yolo silt loam) was investigated using a batch equilibration method. Sorption isotherms of herbicides to biochars were well described by the Freundlich model (R(2) = 0.93-0.97). The adsorption KF values ranged from 6.94 to 1306.95 mg kg(-1) and indicated the sorption of herbicides in the biochars and Yolo soil was in the sequence of linuron > diuron > monuron and walnut shell biochar > wood feedstock biochar > turkey litter biochar > enhanced biochar > hog waste biochar > Yolo soil. These data show that sorption of herbicides to biochar can have both positive (reduced off-site transport) and negative (reduced herbicide efficacy) implications and specific biochar properties, such as H/C ratio and surface area, should be considered together with soil type, agriculture chemical and climate condition in biochar application to agricultural soil to optimize the system for both agricultural and environmental benefits. PMID:26065514

  17. About soil cover heterogeneity of agricultural research stations' experimental fields

    NASA Astrophysics Data System (ADS)

    Rannik, Kaire; Kõlli, Raimo; Kukk, Liia

    2013-04-01

    Depending on local pedo-ecological conditions (topography, (geo) diversity of soil parent material, meteorological conditions) the patterns of soil cover and plant cover determined by soils are very diverse. Formed in the course of soil-plant mutual relationship, the natural ecosystems are always influenced to certain extent by the other local soil forming conditions or they are site specific. The agricultural land use or the formation of agro-ecosystems depends foremost on the suitability of soils for the cultivation of feed and food crops. As a rule, the most fertile or the best soils of the area, which do not present any or present as little as possible constraints for agricultural land use, are selected for this purpose. Compared with conventional field soils, the requirements for the experimental fields' soil cover quality are much higher. Experimental area soils and soil cover composition should correspond to local pedo-ecological conditions and, in addition to that, represent the soil types dominating in the region, whereas the fields should be as homogeneous as possible. The soil cover heterogeneity of seven arable land blocks of three research stations (Jõgeva, Kuusiku and Olustvere) was studied 1) by examining the large scale (1:10 000) digital soil map (available via the internet), and 2) by field researches using the transect method. The stages of soils litho-genetic and moisture heterogeneities were estimated by using the Estonian normal soils matrix, however, the heterogeneity of top- and subsoil texture by using the soil texture matrix. The quality and variability of experimental fields' soils humus status, was studied more thoroughly from the aspect of humus concentration (g kg-1), humus cover thickness (cm) and humus stocks (Mg ha-1). The soil cover of Jõgeva experimental area, which presents an accumulative drumlin landscape (formed during the last glacial period), consist from loamy Luvisols and associated to this Cambisols. In Kuusiku area

  18. Deep Soil: Quantifying and Modeling Subsurface Carbon

    NASA Astrophysics Data System (ADS)

    James, J. N.; Devine, W.; Harrison, R. B.

    2014-12-01

    Some soil carbon datasets that are spatially rich, such as the USDA Forest Service Inventory and Analysis National Program dataset, sample soil to only 20 cm (8 inches), despite evidence that substantial stores of soil C can be found deeper in the soil profile. The maximum extent of tree rooting is typically many meters deep and provides: direct exchange with the soil solution; redistribution of water from deep horizons toward the surface during times of drought; resources for active microbial communities in deep soil around root channels; and direct carbon inputs through exudates and root turnover. This study examined soil carbon to a depth of 2.5 meters across 22 soils in Pacific Northwest Douglas-fir forests. Excavations at 20 additional sites took place in summer 2014, greatly expanding the spatial coverage and extent of the data set. Forest floor and mineral soil bulk density samples were collected at depths of 0.1, 0.5, 1.0, 1.5, 2.0 and 2.5 meters. Pool estimates from systematic sampling depths shallower than 1.5 m yielded significantly smaller estimates than the total soil stock to 2.5 meters (P<0.01). On average, only 5% of soil C was found in the litter layer, 35% was found below 0.5 meter, and 21% was found below 1.0 meter. Due to the difficulty of excavating and measuring deep soil carbon, a series of nonlinear mixed effect models were fit to the data to predict deep soil carbon stocks given sampling to 1.0 meter. A model using an inverse polynomial function predicted soil carbon to 2.5 meters with -5.6% mean error. The largest errors occurred in Andisols with non-crystalline minerals, which can adsorb large quantities of carbon on mineral surfaces and preserve it from decomposition. An accurate spatial dataset of soil depth to bedrock would be extremely useful to constrain models of the vertical distribution of soil carbon. Efforts to represent carbon in spatial models would benefit from considering the vertical distribution of carbon in soil. Sampling

  19. Soil carbon sequestration via cover crops- A meta-analysis

    NASA Astrophysics Data System (ADS)

    Poeplau, Christopher; Don, Axel

    2014-05-01

    Agricultural soils are depleted in soil organic carbon (SOC) and have thus a huge potential to sequester SOC. This can primarily be achieved by increasing carbon inputs into the soil. Replacing winter fallows by cover crop cultivation for green manure has many benefits for the soil and forms an additional carbon input. An increase in carbon concentration has been reported in several studies worldwide. However, the effect on SOC stocks, as well as the influence of environmental parameters and management on SOC dynamics is not known. We therefore conducted a meta-analysis to investigate those issues. A total of 33 studies, comprising 47 sites and 147 plots were compiled. A pedotransfer function was used to estimate bulk densities and calculate SOC stocks. SOC stock change was found to be a linear function of time since introduction, with an annual sequestration rate of 0.32 Mg C ha-1 yr-1. Since no saturation was visible in the observations, we used the model RothC to estimate a new steady state level and the resulting total SOC stock change for an artificial "average cropland". The total average SOC stock change with an annual input of 1.87 Mg C ha-1 yr-1 was 16.76 Mg C ha-1 for the average soil depth of 22 cm. We estimated a potential global SOC sequestration of 0.12±0.03 Pg C yr-1, which would compensate for 8 % of the direct annual greenhouse gas emissions from agriculture.

  20. Increasing the sink: agricultural management and soil carbon dynamics: western U.S. croplands. In: Liebig, M., Franzluebbers, A., and Follet, R., editors. Managing agricultural greenhouse gasses. 1st edition. Waltham, MA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this chapter is to provide a short review and update of potential crop management practices that have had beneficial or detrimental effects on soil C storage in Western U.S. croplands, with emphasize on studies reported since 2005. This review of published literature indicates that C ...

  1. Mineralization of soil organic matter in biochar amended agricultural landscape

    NASA Astrophysics Data System (ADS)

    Chintala, R.; Clay, D. E.; Schumacher, T. E.; Kumar, S.; Malo, D. D.

    2015-12-01

    Pyrogenic biochar materials have been identified as a promising soil amendment to enhance climate resilience, increase soil carbon recalcitrance and achieve sustainable crop production. A three year field study was initiated in 2013 to study the impact of biochar on soil carbon and nitrogen storage on an eroded Maddock soil series - Sandy, Mixed, Frigid Entic Hapludolls) and deposition Brookings clay loam (Fine-Silty, Mixed, Superactive, Frigid Pachic Hapludolls) landscape positions. Three biochars produced from corn stover (Zea mays L.), Ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue, and switchgrass (Panicum virgatum L.) were incorporated at 9.75 Mg ha-1 rate (≈7.5 cm soil depth and 1.3 g/cm3 soil bulk density) with a rototiller. The changes in chemical fractionation of soil carbon (soluble C, acid hydrolyzable C, total C, and δ13 C) and nitrogen (soluble N, acid hydrolyzable N, total N, and δ14 N) were monitored for two soil depths (0-7.5 and 7.5 - 15 cm). Soluble and acid hydrolyzable fractions of soil C and N were influenced by soil series and were not significantly affected by incorporation of biochars. Based on soil and plant samples to be collected in the fall of 2015, C and N budgets are being developed using isotopic and non-isotopic techniques. Laboratory studies showed that the mean residence time for biochars used in this study ranged from 400 to 666 years. Laboratory and field studies will be compared in the presentation.

  2. Biogenic carbon fluxes from global agricultural production and consumption: Gridded, annual estimates of net ecosystem carbon exchange

    NASA Astrophysics Data System (ADS)

    Wolf, J.; West, T. O.; le Page, Y.; Thomson, A. M.

    2014-12-01

    Quantification of biogenic carbon fluxes from agricultural lands is needed to generate globally consistent bottom-up estimates for carbon monitoring and model input. We quantify agricultural carbon fluxes associated with annual (starting in 1961) crop net primary productivity (NPP), harvested biomass, and human and livestock consumption and emissions, with estimates of uncertainty, by applying region- and species-specific carbon parameters to annual crop, livestock, food and trade inventory data, and generate downscaled, gridded (0.05 degree resolution) representations of these fluxes. In 2011, global crop NPP was 5.25 ± 0.46 Pg carbon (excluding root exudates), of which 2.05 ± 0.051 Pg carbon was harvested as primary crops; an additional 0.54 Pg of crop residue carbon was collected for livestock fodder. In 2011, total livestock feed intake was 2.42 ± 0.21 Pg carbon, of which 2.31 ± 0.21 Pg carbon was emitted as carbon dioxide and 0.072 ± 0.005 Pg carbon was emitted as methane. We estimate that livestock grazed 1.18 Pg carbon from non-crop lands in 2011, representing 48.5 % of global total feed intake. In 2009, the latest available data year, we estimate global human food intake (excluding seafood and orchard fruits and nuts) at 0.52 ± 0.03 Pg carbon, with an additional 0.24 ± 0.01 Pg carbon of food supply chain losses. Trends in production and consumption of agricultural carbon between 1961 and recent years, such as increasing dominance of oilcrops and decreasing percent contribution of pasturage to total livestock feed intake, are discussed, and accounting of all agricultural carbon was done for the years 2005 and 2009. Gridded at 0.05 degree resolution, these quantities represent local uptake and release of agricultural biogenic carbon (e.g. biomass production and removal, residue and manure inputs to soils) and may be used with other gridded data to help estimate current and future changes in soil organic carbon.

  3. Using Strontium Isotopes in Arid Agricultural Soils to Determine a Sink or Source of CO2

    NASA Astrophysics Data System (ADS)

    Ortiz, A. C.; Jin, L.

    2014-12-01

    Arid and semi-arid regions of the world are predicted to continue to expand through land degradation and prolonged drought events. Agricultural practices in these drylands degrade soils through elevated salinity, sodicity and alkalinity. Indeed, flood irrigation loads salts onto the soils including carbonate minerals in the form of calcite. Alfalfa and Pecan are salt tolerant and commonly grown in the arid El Paso region, but need irrigation using Rio Grande water with little to no contribution from local ground waters. We hypothesize that the irrigation is loading extra Ca and bicarbonate to soils and anthropogenically enhancing the precipitation of carbonates. We intend to monitor soil CO2 efflux after irrigation, characterize soil minerals, and combine them to isotopic data of soil, irrigation, and drainage waters to link the sources of Ca and C, kinetics of calcite precipitation, to irrigation events. This will include strontium isotopic analysis to determine the source of calcium in the agricultural fields, U-disequilibrium isotopes to estimate the carbonate ages, and CO2 efflux to monitor atmosphere-soil exchange. Carbon dioxide emissions are expected to change during flood irrigation when soils are saturated. After irrigation events, evaporative effects increase Ca and dissolved inorganic carbon concentration in soil waters leading to precipitation of calcite and thus elevated CO2efflux. Preliminary measurements in the pecan field show a marginally significant difference in CO2 fluxes before and after irrigation (p=0.07, t-test). Carbon dioxide emissions are lower during moist conditions (0.6 g m-2hr-1 CO2) than those in dry conditions (1.0 g m-2hr-1 CO2). Future C isotope data are needed to identify the source of extra CO2, biogenic or calcite-precipitation related. A water leachable extraction of alfalfa soils shows 87Sr/86Sr ratios ranged from 0.7101 to 0.7103, indicating Rio Grande river as a dominant calcium source. Further Sr isotopic analysis of

  4. Mechanisms of Soil Carbon Sequestration

    NASA Astrophysics Data System (ADS)

    Lal, Rattan

    2015-04-01

    Carbon (C) sequestration in soil is one of the several strategies of reducing the net emission of CO2 into the atmosphere. Of the two components, soil organic C (SOC) and soil inorganic C (SIC), SOC is an important control of edaphic properties and processes. In addition to off-setting part of the anthropogenic emissions, enhancing SOC concentration to above the threshold level (~1.5-2.0%) in the root zone has numerous ancillary benefits including food and nutritional security, biodiversity, water quality, among others. Because of its critical importance in human wellbeing and nature conservancy, scientific processes must be sufficiently understood with regards to: i) the potential attainable, and actual sink capacity of SOC and SIC, ii) permanence of the C sequestered its turnover and mean residence time, iii) the amount of biomass C needed (Mg/ha/yr) to maintain and enhance SOC pool, and to create a positive C budget, iv) factors governing the depth distribution of SOC, v) physical, chemical and biological mechanisms affecting the rate of decomposition by biotic and abiotic processes, vi) role of soil aggregation in sequestration and protection of SOC and SIC pool, vii) the importance of root system and its exudates in transfer of biomass-C into the SOC pools, viii) significance of biogenic processes in formation of secondary carbonates, ix) the role of dissolved organic C (DOC) in sequestration of SOC and SIC, and x) importance of weathering of alumino-silicates (e.g., powered olivine) in SIC sequestration. Lack of understanding of these and other basic processes leads to misunderstanding, inconsistencies in interpretation of empirical data, and futile debates. Identification of site-specific management practices is also facilitated by understanding of the basic processes of sequestration of SOC and SIC. Sustainable intensification of agroecosystems -- producing more from less by enhancing the use efficiency and reducing losses of inputs, necessitates thorough

  5. Lunar base agriculture: Soils for plant growth

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Editor); Henninger, Donald L. (Editor)

    1989-01-01

    This work provides information on research and experimentation concerning various aspects of food production in space and particularly on the moon. Options for human settlement of the moon and Mars and strategies for a lunar base are discussed. The lunar environment, including the mineralogical and chemical properties of lunar regolith are investigated and chemical and physical considerations for a lunar-derived soil are considered. It is noted that biological considerations for such a soil include controlled-environment crop production, both hydroponic and lunar regolith-based; microorganisms and the growth of higher plants in lunar-derived soils; and the role of microbes to condition lunar regolith for plant cultivation. Current research in the controlled ecological life support system (CELSS) project is presented in detail and future research areas, such as the growth of higher research plants in CELSS are considered. Optimum plant and microbiological considerations for lunar derived soils are examined.

  6. A method to detect soil carbon degradation during soil erosion

    NASA Astrophysics Data System (ADS)

    Alewell, Christine; Conen, Franz; Schaub, Monika

    2010-05-01

    Soil erosion has been discussed intensively but controversial both as a significant source or a significant sink of atmospheric carbon possibly explaining the gap in the global carbon budget. One of the major points of discussion has been whether or not carbon is degraded and mineralized to CO2 during detachment, transport and deposition of soil material. By combining the caesium-137 (137Cs) approach (quantification of erosion rates) with stable carbon isotope signatures (process indicator of mixing versus degradation of carbon pools) we were able to show that degradation of carbon occurs during soil erosion processes at the investigated mountain grasslands in the central Swiss Alps (Urseren Valley, Canton Uri). Transects from upland (erosion source) to wetland soils (erosion sinks) of sites affected by sheet and land slide erosion were sampled. Analysis of 137Cs yielded an input of 2 and 4.6 tha-1 yr-1 of soil material into the wetlands sites. Assuming no degradation of soil organic carbon during detachment and transport, carbon isotope signature of soil organic carbon in the wetlands could only be explained with an assumed 500-600 and 350-400 years of erosion input into the wetlands Laui and Spissen, respectively. The latter is highly unlikely with alpine peat growth rates indicating that the upper horizons might have an age between 7 and 200 years. While we do not conclude from our data that eroded soil organic carbon is generally degraded during detachment and transport, we propose this method to gain more information on process dynamics during soil erosion from oxic upland to anoxic wetland soils, sediments or water bodies.

  7. A method to detect soil carbon degradation during soil erosion

    NASA Astrophysics Data System (ADS)

    Alewell, C.; Schaub, M.; Conen, F.

    2009-06-01

    Soil erosion has been discussed intensively but controversial both as a significant source or a significant sink of atmospheric carbon possibly explaining the gap in the global carbon budget. One of the major points of discussion has been whether or not carbon is degraded and mineralized to CO2 during detachment, transport and deposition of soil material. By combining the caesium-137 (137Cs) approach (quantification of erosion rates) with stable carbon isotope signatures (process indicator of mixing versus degradation of carbon pools) we were able to show that degradation of carbon occurs during soil erosion processes at the investigated mountain grasslands in the central Swiss Alps (Urseren Valley, Canton Uri). Transects from upland (erosion source) to wetland soils (erosion sinks) of sites affected by sheet and land slide erosion were sampled. Analysis of 137Cs yielded an input of 2 and 2.6 t ha-1 yr-1 of soil material into the wetlands sites. Assuming no degradation of soil organic carbon during detachment and transport, carbon isotope signature of soil organic carbon in the wetlands could only be explained with an assumed 800 and 400 years of erosion input into the wetlands. The latter is highly unlikely with alpine peat growth rates indicating that the upper horizons might have an age between 7 and 200 years. While we do not conclude from our data that eroded soil organic carbon is generally degraded during detachment and transport, we propose this method to gain more information on process dynamics during soil erosion from oxic upland to anoxic wetland soils, sediments or water bodies.

  8. A method to detect soil carbon degradation during soil erosion

    NASA Astrophysics Data System (ADS)

    Alewell, C.; Schaub, M.; Conen, F.

    2009-11-01

    Soil erosion has been discussed intensively but controversial both as a significant source or a significant sink of atmospheric carbon possibly explaining the gap in the global carbon budget. One of the major points of discussion has been whether or not carbon is degraded and mineralized to CO2 during detachment, transport and deposition of soil material. By combining the caesium-137 (137Cs) approach (quantification of erosion rates) with stable carbon isotope signatures (process indicator of mixing versus degradation of carbon pools) we were able to show that degradation of carbon occurs during soil erosion processes at the investigated mountain grasslands in the central Swiss Alps (Urseren Valley, Canton Uri). Transects from upland (erosion source) to wetland soils (erosion sinks) of sites affected by sheet and land slide erosion were sampled. Analysis of 137Cs yielded an input of 2 and 4.6 tha-1 yr-1 of soil material into the wetlands sites. Assuming no degradation of soil organic carbon during detachment and transport, carbon isotope signature of soil organic carbon in the wetlands could only be explained with an assumed 500-600 and 350-400 years of erosion input into the wetlands Laui and Spissen, respectively. The latter is highly unlikely with alpine peat growth rates indicating that the upper horizons might have an age between 7 and 200 years. While we do not conclude from our data that eroded soil organic carbon is generally degraded during detachment and transport, we propose this method to gain more information on process dynamics during soil erosion from oxic upland to anoxic wetland soils, sediments or water bodies.

  9. Carbosoil, a land evaluation model for soil carbon accounting

    NASA Astrophysics Data System (ADS)

    Anaya-Romero, M.; Muñoz-Rojas, M.; Pino, R.; Jordan, A.; Zavala, L. M.; De la Rosa, D.

    2012-04-01

    The belowground carbon content is particularly difficult to quantify and most of the time is assumed to be a fixed fraction or ignored for lack of better information. In this respect, this research presents a land evaluation tool, Carbosoil, for predicting soil carbon accounting where this data are scarce or not available, as a new component of MicroLEIS DSS. The pilot study area was a Mediterranean region (Andalusia, Southern Spain) during 1956-2007. Input data were obtained from different data sources and include 1689 soil profiles from Andalusia (S Spain). Previously, detailed studies of changes in LU and vegetation carbon stocks, and soil organic carbon (SOC) dynamic were carried out. Previous results showed the influence of LU, climate (mean temperature and rainfall) and soil variables related with SOC dynamics. For instance, SCS decreased in Cambisols and Regosols by 80% when LU changed from forest to heterogeneous agricultural areas. Taking this into account, the input variables considered were LU, site (elevation, slope, erosion, type-of-drainage, and soil-depth), climate (mean winter/summer temperature and annual precipitation), and soil (pH, nitrates, CEC, sand/clay content, bulk density and field capacity). The available data set was randomly split into two parts: training-set (75%), and validation-set (25%). The model was built by using multiple linear regression. The regression coefficient (R2) obtained in the calibration and validation of Carbosoil was >0.9 for the considered soil sections (0-25, 25-50, and 50-75 cm). The validation showed the high accuracy of the model and its capacity to discriminate carbon distribution regarding different climate, LU and soil management scenarios. Carbosoil model together with the methodologies and information generated in this work will be a useful basis to accurately quantify and understanding the distribution of soil carbon account helpful for decision makers.

  10. Are Mexican agricultural farmlands PCDD/F soil reservoirs?

    PubMed

    Haro-García, Luis; Villa-Ibarra, Martín; Chaín-Castro, Teresita de Jesús; Lastra-Rodríguez, Angel; Juárez-Pérez, Cuauhtémoc Arturo; Aguilar-Madrid, Guadalupe; Sánchez-Escalante, Vanessa Crystal; Brito-Zurita, Olga Rosa

    2012-06-01

    Our aim was to identify polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-p-furans (PCDFs) in agricultural farmland soils in the Northwest of Mexico. We obtained ≈50 g of soil in five Yaqui Valley (VY) agricultural fields in the north-western Mexican State of Sonora and in five Culiacán Valley (VC) agricultural fields in the north-western Mexican State of Sinaloa. Fields with minimal tillage, with ferti-irrigation, and those with intensive aerial and manual tillage were included. All soil samples were subjected to the chemical activated luciferase gene expression (CALUX(®)) test to determine PCDD/F. On average, samples contained 4.2 ± 1.2 PCDD/F ppt TEQ; VY soil samples contained 4.72 ± 1.23 PCDD/F ppt TEQ, while VC soil samples showed 3.6 ± 1.1 PCDD/F ppt TEQ (p = 0.47). On considering tillage-type, in agricultural fields catalogued as intensive tillage, PCDD/F concentrations were 4.40 ± 0.43 in agricultural fields catalogued as intensive tillage, while in farmlands of another tillage-type these concentrations were slightly higher (5.53 ± 0.8).

  11. Activity concentration of caesium-137 in agricultural soils.

    PubMed

    Aslani, Mahmoud A A; Aytas, Sule; Akyil, Sema; Yaprak, Gunseli; Yener, Gungor; Eral, Meral

    2003-01-01

    In this study, we measured 137Cs activity concentrations in the soil samples taken from agricultural lands in the Buyuk Menderes Basin in Turkey in 1997 and 1998. The soil samples were collected from 42 sites in this Basin. The activity concentration of 137Cs was found to range between 2.81+/-0.17 Bq.kg(-1) and 20.75+/-0.29 Bq.kg(-1). The effect of organic matter, clay, silt and sand contents and pH of the soil on the relative adsorption of the 137Cs on the soil surface were also studied.

  12. Stuffing Carbon Away: Mechanisms of Carbon Sequestration in Soils

    SciTech Connect

    Reimer, P J; Masiello, C A; Southon, J R; Trumbore, S E; Harden, J W; White, A F; Chadwick, O A; Torn, M S

    2003-01-24

    Soils offer the potential to sequester large quantities of carbon from the atmosphere for decades to millennia and so may ameliorate the anthropogenic influence of fossil fuel release. However changes in climate can drastically affect the soil's ability to store carbon through changes mineralogy on time scales of human interest. It is essential to understand the major controls on soil carbon dynamics before we attempt to manage sequestration to control atmospheric CO{sub 2} buildup. Models of the terrestrial carbon cycle often use clay content to parameterize soil carbon turnover. Evidence from volcanic soils suggests that soil mineralogy is a major control on a soil's ability to store carbon, because different types of minerals have widely varying abilities to physically and chemically isolate soil organic matter from decomposition, however volcanic soils represent only a small percentage of the earth's soils. The relationship between precipitation and soil carbon storage is also complex and poorly constrained. Significantly, precipitation changes predicted as a result of atmospheric CO{sub 2} doubling include increased rainfall throughout California. We utilized {sup 14}C, {delta}{sup 13}C, and the total organic carbon, iron, and aluminum contents to address the question of the importance of mineralogy and climate on carbon storage in soils formed on a globally representative parent material. The California coastal terraces, formed over the last 500 thousand years as a result of tectonic uplift and sea level change, provide a natural laboratory to examine the effect of mineralogy and climate on carbon storage. We have focused on two terraces sequences, one near Eureka and one near Santa Cruz. Within each set of terraces only soil mineral development varies; all other variables are constant (rainfall, plant systems, and soil parent material, and land management). Annual precipitation at Eureka is twice that at Santa Cruz, allowing us to examine its role in the

  13. Impacts of crop rotations on soil organic carbon sequestration

    NASA Astrophysics Data System (ADS)

    Gobin, Anne; Vos, Johan; Joris, Ingeborg; Van De Vreken, Philippe

    2013-04-01

    Agricultural land use and crop rotations can greatly affect the amount of carbon sequestered in the soil. We developed a framework for modelling the impacts of crop rotations on soil carbon sequestration at the field scale with test case Flanders. A crop rotation geo-database was constructed covering 10 years of crop rotation in Flanders using the IACS parcel registration (Integrated Administration and Control System) to elicit the most common crop rotation on major soil types in Flanders. In order to simulate the impact of crop cover on carbon sequestration, the Roth-C model was adapted to Flanders' environment and coupled to common crop rotations extracted from the IACS geodatabases and statistical databases on crop yield. Crop allometric models were used to calculate crop residues from common crops in Flanders and subsequently derive stable organic matter fluxes to the soil (REGSOM). The REGSOM model was coupled to Roth-C model was run for 30 years and for all combinations of seven main arable crops, two common catch crops and two common dosages of organic manure. The common crops are winter wheat, winter barley, sugar beet, potato, grain maize, silage maize and winter rapeseed; the catch crops are yellow mustard and Italian ryegrass; the manure dosages are 35 ton/ha cattle slurry and 22 ton/ha pig slurry. Four common soils were simulated: sand, loam, sandy loam and clay. In total more than 2.4 million simulations were made with monthly output of carbon content for 30 years. Results demonstrate that crop cover dynamics influence carbon sequestration for a very large percentage. For the same rotations carbon sequestration is highest on clay soils and lowest on sandy soils. Crop residues of grain maize and winter wheat followed by catch crops contribute largely to the total carbon sequestered. This implies that agricultural policies that impact on agricultural land management influence soil carbon sequestration for a large percentage. The framework is therefore

  14. The Living Soil: Exploring Soil Science and Sustainable Agriculture with Your Guide, The Earthworm. Unit I.

    ERIC Educational Resources Information Center

    Weber, Eldon C.; And Others

    This instructional packet introduces students to soil biology, ecology, and specific farming practices that promote sustainable agriculture. It helps students to discover the role of earthworms in improving the environment of all other soil-inhabiting organisms and in making the soil more fertile. The activities (classroom as well as outdoor)…

  15. Soil Organic Carbon Change Monitored Over Large Areas

    SciTech Connect

    Brown, David J.; Hunt, E. Raymond; Izaurralde, Roberto C.; Paustian, Keith H.; Rice, Charles W.; West, Tristram O.; Schumaker, Bonny L.

    2010-08-31

    Soils account for the largest fraction of terrestrial carbon (C); thus, they are critically important in determining global C cycle dynamics. In North America, conversion of native prairies to agricultural land use over 150 years ago released 30-50% of the soil organic carbon (SOC). Improved agricultural practices have the capacity to recover much of this SOC, storing it in biomass and soil and thereby removing billions of tons of atmospheric CO2. These practices involve increasing C inputs to soil (e.g., by crop rotations, increased use of higher biomass crops, perennial crops) and decreased losses (e.g., reduced tillage intensity) [Janzen et al., 1998; Lal et al., 2003; Smith et al., 2007]. Managing agricultural soils to increase SOC storage is a significant, immediately available, low-cost option for mitigating CO2 emissions, with a technical potential to offset as much as 800 Tg CO2/yr in the US (~13% of US CO2 emissions) [Lal et al., 2003] and 5000 Tg CO2/yr globally (~17% of global CO2 emissions) [Smith et al., 2007].

  16. Organic carbon in soil and the global carbon cycle

    SciTech Connect

    Post, W.M. III

    1991-12-31

    Soil organic matter is, simultaneously, the most inert carbon cycle component of terrestrial ecosystems, and the most dynamic component of terrestrail geologic systems placing it in a pivotal position in the biogeochemistry of carbon. The large size and potentially long residence time of the soil organic matter pool make it an important component of the global carbon cycle. Net terrestrial primary production of about 60 Pg C{center_dot}yr{sup {minus}1} is, over a several-year period of time, balanced by an equivalent flux of litter production and subsequent decomposition of detritus and soil organic matter. However, the input rates and decomposition rates for different terrestrial ecosystems vary over several orders of magnitude resulting in widely different amounts and turnover rates of soil organic matter. The amounts of carbon stored in soils and the rates of exchange of soil carbon with the atmosphere depend on many factors related to the chemistry, biology, and physics of soil and soil organic matter. This report discusses work on organic carbon in soil and aspects of the carbon cycle.

  17. Multivariate regulation of soil CO2 and N2 O pulse emissions from agricultural soils.

    PubMed

    Liang, Liyin L; Grantz, David A; Jenerette, G Darrel

    2016-03-01

    Climate and land-use models project increasing occurrence of high temperature and water deficit in both agricultural production systems and terrestrial ecosystems. Episodic soil wetting and subsequent drying may increase the occurrence and magnitude of pulsed biogeochemical activity, affecting carbon (C) and nitrogen (N) cycles and influencing greenhouse gas (GHG) emissions. In this study, we provide the first data to explore the responses of carbon dioxide (CO2 ) and nitrous oxide (N2 O) fluxes to (i) temperature, (ii) soil water content as percent water holding capacity (%WHC), (iii) substrate availability throughout, and (iv) multiple soil drying and rewetting (DW) events. Each of these factors and their interactions exerted effects on GHG emissions over a range of four (CO2 ) and six (N2 O) orders of magnitude. Maximal CO2 and N2 O fluxes were observed in environments combining intermediate %WHC, elevated temperature, and sufficient substrate availability. Amendments of C and N and their interactions significantly affected CO2 and N2 O fluxes and altered their temperature sensitivities (Q10 ) over successive DW cycles. C amendments significantly enhanced CO2 flux, reduced N2 O flux, and decreased the Q10 of both. N amendments had no effect on CO2 flux and increased N2 O flux, while significantly depressing the Q10 for CO2 , and having no effect on the Q10 for N2 O. The dynamics across DW cycles could be attributed to changes in soil microbial communities as the different responses to wetting events in specific group of microorganisms, to the altered substrate availabilities, or to both. The complex interactions among parameters influencing trace gas fluxes should be incorporated into next generation earth system models to improve estimation of GHG emissions. PMID:26470015

  18. Sorption and transport of atrazine in an agricultural soil

    NASA Astrophysics Data System (ADS)

    Hakan Akyol, Nihat

    2014-05-01

    Sorption and transport of atrazine in an agricultural soil Atrazine is one of the most commonly used herbicides in large quantity worldwide. The objective of this study was to perform some batch and column experiments to examine the transport of atrazine in an agricultural soil from Turkey. Batch experiments indicated that sorption isotherm was nonlinear with a freundlich isotherm over a range of concentration (0.2-10 mg/L) examined. Column experiments showed that transport of atrazine in the soil was moderately retarded compared to non-reactive tracer (R = 2.9-4.0). The degree of retardation decreased with increasing atrazine concentration and residance time had negligable impact on degree of sorption. Flow interruption tests in the column experiments indicated that the rate-limited desorption of atrazine mainly controlled the non-ideal transport of atrazine due to the presence of organic matter fraction (0.83 %) in the soil. Sorption and desorption behavior of atrazine in such soils could have important impacts for risk assessment of atrazine-contaminated soil and should be taken into account in the regulation, management, and remediation of atrazine-contaminated sites. Keywords: Atrazine, Agricultural soil, Batch, Column, Desorption, Rate-limited desorption, Sorption, Transport.

  19. Effects of Nitrogen Fertilizer and Harvesting Frequency on Soil Organic Matter Pools Under Switchgrass Agriculture

    NASA Astrophysics Data System (ADS)

    Valdez, Z. P.; Hockaday, W. C.; Gallagher, M. E.; Masiello, C. A.; Gao, X.

    2013-12-01

    Intensive agriculture has the potential to reduce soil carbon stocks in the years following initial cultivation, although the magnitude and direction of the effect can vary with ecosystem and management factors. The cropping of switchgrass (Panicum virgatum) for biomass shows potential for high yields in marginal lands with low fertilizer inputs, while the extensive root system can act to improve soil quality and sequester atmospheric carbon dioxide in the soil carbon pool. We are investigating the impact of nitrogen fertilizer inputs and harvesting frequency on soil organic matter quantity and quality in a biofuels cropping trial in Michigan. Here we test the hypothesis that harvest and fertilization rate can affect the partitioning of organic matter into different storage pools within the 0-60 cm of soil: roots, particulate organic matter (POM) (density <1.8 g/cm3), and protected organic matter (density > 1.8 g/cm3). Additionally, we use 13C Nuclear Magnetic Resonance (NMR) spectroscopy to study the bulk chemistry (carbohydrate, lignin, lipid, and protein) of the roots and POM. The NMR data also allow us to estimate the relative decomposition of the soil organic matter using a standard decomposition index (alkyl/O-alkyl peak ratio). We use the data to infer the influence of crop management on the mechanisms of soil C storage and mechanisms of stabilization in switchgrass agriculture. Initial results have shown a significant change in carbon stocks at depths between 15-60 cm for the high and low fertilization rates, 196 kg/m3 and 0kg/m3 respectively, although the harvesting time and frequency did not create a substantial difference on carbon stocks. The root bulk chemistry has not shown consistent results among management practices

  20. Formative pre-Hispanic agricultural soils in northwest Argentina

    NASA Astrophysics Data System (ADS)

    Sampietro Vattuone, María Marta; Roldán, Jimena; Neder, Liliana; Maldonado, Mario Gabriel; Vattuone, Marta Amelia

    2011-01-01

    Our study area is from an early agricultural archaeological site named "El Tolar" (1st to 9th century AD), located in Tafí Valley (Tucumán, northwest Argentina). The objective was to identify geochemical signatures generated by the sustained agrarian use of soils. Chemical and pedological studies were made in different archaeological contexts. Physical and chemical features, such as bulk density, pH, organic and inorganic phosphorus, and available copper, manganese and iron, were taken into account. The results suggested that a buried paleosol identified was contemporary with the occupation of the site. It also showed characteristics clearly related to pre-Hispanic agrarian production. The concentrations of organic phosphorus and iron in agricultural soils probably reflect the use of fertilizers. The application of geoscience techniques allowed us to obtain important information on their behaviour and socio-economic development. This paper constitutes the first pedogeochemical approach to the study of Argentinean pre-Hispanic agricultural soils.

  1. Soil Organic Carbon Mapping by Geostatistics in Europe Scale

    NASA Astrophysics Data System (ADS)

    Aksoy, E.; Panagos, P.; Montanarella, L.

    2013-12-01

    Accuracy in assessing the distribution of soil organic carbon (SOC) is an important issue because SOC is an important soil component that plays key roles in the functions of both natural ecosystems and agricultural systems. The SOC content varies from place to place and it is strongly related with climate variables (temperature and rainfall), terrain features, soil texture, parent material, vegetation, land-use types, and human management (management and degradation) at different spatial scales. Geostatistical techniques allow for the prediction of soil properties using soil information and environmental covariates. In this study, assessment of SOC distribution has been predicted with Regression-Kriging method in Europe scale. In this prediction, combination of the soil samples which were collected from the LUCAS (European Land Use/Cover Area frame statistical Survey) & BioSoil Projects, with local soil data which were collected from six different CZOs in Europe and ten spatial predictors (slope, aspect, elevation, CTI, CORINE land-cover classification, parent material, texture, WRB soil classification, annual average temperature and precipitation) were used. Significant correlation between the covariates and the organic carbon dependent variable was found. Moreover, investigating the contribution of local dataset in watershed scale into regional dataset in European scale was an important challenge.

  2. Roles of black carbon on the fate of heavy metals and agrochemicals in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Char(coal) and other black carbon materials can comprise up to 35% of total organic carbon in US agricultural soils, and are known to strongly and often irreversibly bind contaminants including heavy metals. Black carbon has received renewed interests in recent years as a solid co-product formed du...

  3. Stable carbon isotope evidence for nitrogenous fertilizer impact on carbonate weathering in a small agricultural watershed.

    PubMed

    Brunet, F; Potot, C; Probst, A; Probst, J-L

    2011-10-15

    The isotopic signature of Dissolved Inorganic Carbon (DIC), δ(13)C(DIC), has been investigated in the surface waters of a small agricultural catchment on calcareous substratum, Montoussé, located at Auradé (south-west France). The Montoussé catchment is subjected to intense farming (wheat/sunflower rotation) and a moderated application of nitrogenous fertilizers. During the nitrification of the NH(4)(+), supplied by fertilization, nitrate and H(+) ions are produced in the soil. This anthropogenic acidity is combined with the natural acidity due to carbonic acid in weathering processes. From an isotopic point of view, with 'natural weathering', using carbonic acid, δ(13)C(DIC) is intermediate between the δ(13)C of soil CO(2) produced by organic matter oxidation and that of the carbonate rocks, while it has the same value as the carbonates when carbonic acid is substituted by another acid like nitric acid derived from nitrogen fertilizer. The δ(13)C(DIC) values range from -17.1‰ to -10.7‰ in Montoussé stream waters. We also measured the δ(13)C of calcareous molassic deposits (average -7.9‰) and of soil organic carbon (between -24.1‰ and -26‰) to identify the different sources of DIC and to estimate their contribution. The δ(13) C(DIC) value indicates that weathering largely follows the carbonic acid pathway at the springs (sources of the stream). At the outlet of the basin, H(+) ions, produced during the nitrification of N-fertilizer, also contribute to weathering, especially during flood events. This result is illustrated by the relationship between δ(13)C(DIC) and the molar ratio NO(3)(-)/(Ca(2+) + Mg(2+)). Consequently, when the contribution of nitrate increases, the δ(13)C(DIC) increases towards the calcareous end-member. This new isotopic result provides evidence for the direct influence of nitrogen fertilizer inputs on weathering, CO(2) consumption and base cation leaching and confirms previous results obtained using the chemistry of the

  4. Remote sensing of agricultural crops and soils

    NASA Technical Reports Server (NTRS)

    Bauer, M. E. (Principal Investigator)

    1982-01-01

    Research results and accomplishments of sixteen tasks in the following areas are described: (1) corn and soybean scene radiation research; (2) soil moisture research; (3) sampling and aggregation research; (4) pattern recognition and image registration research; and (5) computer and data base services.

  5. Spatial patterns of soil organic carbon stocks in Estonian arable soils

    NASA Astrophysics Data System (ADS)

    Suuster, Elsa; Astover, Alar; Kõlli, Raimo; Roostalu, Hugo; Reintam, Endla; Penu, Priit

    2010-05-01

    Soil organic carbon (SOC) determines ecosystem functions, influencing soil fertility, soil physical, chemical and biological properties and crop productivity. Therefore the spatial pattern of SOC stocks and its appropriate management is important at various scales. Due to climate change and the contribution of carbon store in the soils, the national estimates of soil carbon stocks should be determined. Estonian soils have been well studied and mapped at a scale 1:10,000. Previous studies have estimated SOC stocks based on combinations of large groups of Estonian soils and the mean values of the soil profile database, but were not embedded into the geo-referenced databases. These studies have estimated SOC stocks of Estonian arable soils 122.3 Tg. Despite of available soil maps and databases, this information is still very poorly used for spatial soil modelling. The aim of current study is to assess and model spatial pattern of SOC stocks of arable soils on a pilot area Tartu County (area 3089 sq km). Estonian digital soil map and soil monitoring databases are providing a good opportunity to assess SOC stocks at various scales. The qualitative nature of the initial data from a soil map prohibits any straightforward use in modelling. Thus we have used several databases to construct models and linkages between soil properties that can be integrated into soil map. First step was to reorganize the soil map database (44,046 mapping units) so it can be used as an input to modelling. Arable areas were distinguished by a field layer of Agricultural Registers and Information Board, which provides precise information of current land use as it is the basis of paying CAP subsidies. The estimates of SOC content were found by using the arable land evaluation database of Tartu from the Estonian Land Board (comprising 950 sq km and 31,226 fields), where each soil type was assessed separately and average SOC content grouped by texture was derived. SOC content of epipedon varies in

  6. Urban cultivation in allotments maintains soil qualities adversely affected by conventional agriculture

    PubMed Central

    Edmondson, Jill L; Davies, Zoe G; Gaston, Kevin J; Leake, Jonathan R

    2014-01-01

    Modern agriculture, in seeking to maximize yields to meet growing global food demand, has caused loss of soil organic carbon (SOC) and compaction, impairing critical regulating and supporting ecosystem services upon which humans also depend. Own-growing makes an important contribution to food security in urban areas globally, but its effects on soil qualities that underpin ecosystem service provision are currently unknown. We compared the main indicators of soil quality; SOC storage, total nitrogen (TN), C : N ratio and bulk density (BD) in urban allotments to soils from the surrounding agricultural region, and between the allotments and other urban greenspaces in a typical UK city. A questionnaire was used to investigate allotment management practices that influence soil properties. Allotment soils had 32% higher SOC concentrations and 36% higher C : N ratios than pastures and arable fields and 25% higher TN and 10% lower BD than arable soils. There was no significant difference between SOC concentration in allotments and urban non-domestic greenspaces, but it was higher in domestic gardens beneath woody vegetation. Allotment soil C : N ratio exceeded that in non-domestic greenspaces, but was lower than that in garden soil. Three-quarters of surveyed allotment plot holders added manure, 95% composted biomass on-site, and many added organic-based fertilizers and commercial composts. This may explain the maintenance of SOC, C : N ratios, TN and low BD, which are positively associated with soil functioning. Synthesis and applications. Maintenance and protection of the quality of our soil resource is essential for sustainable food production and for regulating and supporting ecosystem services upon which we depend. Our study establishes, for the first time, that small-scale urban food production can occur without the penalty of soil degradation seen in conventional agriculture, and maintains the high soil quality seen in urban greenspaces. Given the

  7. Occurrence of veterinary antibiotics and progesterone in broiler manure and agricultural soil in Malaysia.

    PubMed

    Ho, Yu Bin; Zakaria, Mohamad Pauzi; Latif, Puziah Abdul; Saari, Nazamid

    2014-08-01

    Repeated applications of animal manure as fertilizer are normal agricultural practices that may release veterinary antibiotics and hormones into the environment from treated animals. Broiler manure samples and their respective manure-amended agricultural soil samples were collected in selected locations in the states of Selangor, Negeri Sembilan and Melaka in Malaysia to identify and quantify veterinary antibiotic and hormone residues in the environment. The samples were analyzed using ultrasonic extraction followed by solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The broiler manure samples were found to be contaminated with at least six target analytes, namely, doxycycline, enrofloxacin, flumequine, norfloxacin, trimethoprim and tylosin. These analytes were detected in broiler manure samples with maximum concentrations reaching up to 78,516 μg kg(-1) dry weight (DW) (doxycycline). For manure-amended agricultural soil samples, doxycycline and enrofloxacin residues were detected in every soil sample. The maximum concentration of antibiotic detected in soil was 1331 μg kg(-1) DW (flumequine). The occurrence of antibiotics and hormones in animal manure at high concentration poses a risk of contaminating agricultural soil via fertilization with animal manure. Some physico-chemical parameters such as pH, total organic carbon (TOC) and metal content played a considerable role in the fate of the target veterinary antibiotics and progesterone in the environment. It was suggested that these parameters can affect the adsorption of pharmaceuticals to solid environmental matrices. PMID:24836135

  8. Occurrence of veterinary antibiotics and progesterone in broiler manure and agricultural soil in Malaysia.

    PubMed

    Ho, Yu Bin; Zakaria, Mohamad Pauzi; Latif, Puziah Abdul; Saari, Nazamid

    2014-08-01

    Repeated applications of animal manure as fertilizer are normal agricultural practices that may release veterinary antibiotics and hormones into the environment from treated animals. Broiler manure samples and their respective manure-amended agricultural soil samples were collected in selected locations in the states of Selangor, Negeri Sembilan and Melaka in Malaysia to identify and quantify veterinary antibiotic and hormone residues in the environment. The samples were analyzed using ultrasonic extraction followed by solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The broiler manure samples were found to be contaminated with at least six target analytes, namely, doxycycline, enrofloxacin, flumequine, norfloxacin, trimethoprim and tylosin. These analytes were detected in broiler manure samples with maximum concentrations reaching up to 78,516 μg kg(-1) dry weight (DW) (doxycycline). For manure-amended agricultural soil samples, doxycycline and enrofloxacin residues were detected in every soil sample. The maximum concentration of antibiotic detected in soil was 1331 μg kg(-1) DW (flumequine). The occurrence of antibiotics and hormones in animal manure at high concentration poses a risk of contaminating agricultural soil via fertilization with animal manure. Some physico-chemical parameters such as pH, total organic carbon (TOC) and metal content played a considerable role in the fate of the target veterinary antibiotics and progesterone in the environment. It was suggested that these parameters can affect the adsorption of pharmaceuticals to solid environmental matrices.

  9. Substantial dust loss of bioavailable phosphorus from agricultural soils

    PubMed Central

    Katra, Itzhak; Gross, Avner; Swet, Nitzan; Tanner, Smadar; Krasnov, Helena; Angert, Alon

    2016-01-01

    Phosphorus (P) is an essential element in terrestrial ecosystems. Knowledge on the role of dust in the biogeochemical cycling of phosphorus is very limited with no quantitative information on aeolian (by wind) P fluxes from soils. The aim of this study is to focus on P cycling via dust emissions under common land-use practices in an arid environment by integration of sample analyses and aeolian experiments. The experiments indicate significant P fluxes by PM10 dust due to agricultural land use. Even in a single wind-dust event at moderate velocity (7.0 m s−1), P flux in conventional agricultural fields can reach 1.83 kg km−2, that accumulates to a considerable amount per year at a regional scale. The results highlight a negative yearly balance in P content (up to hundreds kg km−2) in all agricultural soils, and thus more P nutrition is required to maintain efficient yield production. In grazing areas where no P nutrition is applied, the soil degradation process can lead to desertification. Emission of P from soil dust sources has significant implications for soil nutrient resources and management strategies in agricultural regions as well as for loading to the atmosphere and global biogeochemical cycles. PMID:27095629

  10. Substantial dust loss of bioavailable phosphorus from agricultural soils

    NASA Astrophysics Data System (ADS)

    Katra, Itzhak; Gross, Avner; Swet, Nitzan; Tanner, Smadar; Krasnov, Helena; Angert, Alon

    2016-04-01

    Phosphorus (P) is an essential element in terrestrial ecosystems. Knowledge on the role of dust in the biogeochemical cycling of phosphorus is very limited with no quantitative information on aeolian (by wind) P fluxes from soils. The aim of this study is to focus on P cycling via dust emissions under common land-use practices in an arid environment by integration of sample analyses and aeolian experiments. The experiments indicate significant P fluxes by PM10 dust due to agricultural land use. Even in a single wind-dust event at moderate velocity (7.0 m s‑1), P flux in conventional agricultural fields can reach 1.83 kg km‑2, that accumulates to a considerable amount per year at a regional scale. The results highlight a negative yearly balance in P content (up to hundreds kg km‑2) in all agricultural soils, and thus more P nutrition is required to maintain efficient yield production. In grazing areas where no P nutrition is applied, the soil degradation process can lead to desertification. Emission of P from soil dust sources has significant implications for soil nutrient resources and management strategies in agricultural regions as well as for loading to the atmosphere and global biogeochemical cycles.

  11. [Organic carbon and carbon mineralization characteristics in nature forestry soil].

    PubMed

    Yang, Tian; Dai, Wei; An, Xiao-Juan; Pang, Huan; Zou, Jian-Mei; Zhang, Rui

    2014-03-01

    Through field investigation and indoor analysis, the organic carbon content and organic carbon mineralization characteristics of six kinds of natural forest soil were studied, including the pine forests, evergreen broad-leaved forest, deciduous broad-leaved forest, mixed needle leaf and Korean pine and Chinese pine forest. The results showed that the organic carbon content in the forest soil showed trends of gradual decrease with the increase of soil depth; Double exponential equation fitted well with the organic carbon mineralization process in natural forest soil, accurately reflecting the mineralization reaction characteristics of the natural forest soil. Natural forest soil in each layer had the same mineralization reaction trend, but different intensity. Among them, the reaction intensity in the 0-10 cm soil of the Korean pine forest was the highest, and the intensities of mineralization reaction in its lower layers were also significantly higher than those in the same layers of other natural forest soil; comparison of soil mineralization characteristics of the deciduous broad-leaved forest and coniferous and broad-leaved mixed forest found that the differences of litter species had a relatively strong impact on the active organic carbon content in soil, leading to different characteristics of mineralization reaction.

  12. Agriculture, forestry, range, and soils, chapter 2, part C

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The feasibility of using microwave systems in agriculture, forestry, range, and soil moisture measurements was studied. Theory and preliminary results show the feasibility of measuring moisture status in the soil. For vegetational resources, crop identification for inventory and for yield and production estimates is most feasible. Apart from moisture- and water-related phenomena, microwave systems are also used to record structural and spatial data related to crops and forests.

  13. How agricultural management shapes soil microbial communities: patterns emerging from genetic and genomic studies

    NASA Astrophysics Data System (ADS)

    Daly, Amanda; Grandy, A. Stuart

    2016-04-01

    Agriculture is a predominant land use and thus a large influence on global carbon (C) and nitrogen (N) balances, climate, and human health. If we are to produce food, fiber, and fuel sustainably we must maximize agricultural yield while minimizing negative environmental consequences, goals towards which we have made great strides through agronomic advances. However, most agronomic strategies have been designed with a view of soil as a black box, largely ignoring the way management is mediated by soil biota. Because soil microbes play a central role in many of the processes that deliver nutrients to crops and support their health and productivity, agricultural management strategies targeted to exploit or support microbial activity should deliver additional benefits. To do this we must determine how microbial community structure and function are shaped by agricultural practices, but until recently our characterizations of soil microbial communities in agricultural soils have been largely limited to broad taxonomic classes due to methodological constraints. With advances in high-throughput genetic and genomic sequencing techniques, better taxonomic resolution now enables us to determine how agricultural management affects specific microbes and, in turn, nutrient cycling outcomes. Here we unite findings from published research that includes genetic or genomic data about microbial community structure (e.g. 454, Illumina, clone libraries, qPCR) in soils under agricultural management regimes that differ in type and extent of tillage, cropping selections and rotations, inclusion of cover crops, organic amendments, and/or synthetic fertilizer application. We delineate patterns linking agricultural management to microbial diversity, biomass, C- and N-content, and abundance of microbial taxa; furthermore, where available, we compare patterns in microbial communities to patterns in soil extracellular enzyme activities, catabolic profiles, inorganic nitrogen pools, and nitrogen

  14. Effects of Tillage Practices on Soil Organic Carbon and Soil Respiration

    NASA Astrophysics Data System (ADS)

    Rusu, Teodor; Ioana Moraru, Paula; Bogdan, Ileana; Ioan Pop, Adrian

    2016-04-01

    replications. In one variant the area of a plot was 300 m2. Soil respiration varies throughout the year for all three crops of rotation, with a maximum in late spring (1383 to 2480 mmoli m-2s-1) and another in fall (2141 to 2350 mmoli m-2s-1). The determinations confirm the effect of soil tillage system on soil respiration; the daily average is lower at no-tillage (315-1914 mmoli m-2s-1), followed by minimum tillage (318-2395 mmoli m-2s-1) and is higher in the conventional tillage (321-2480 mmol m-2s-1). An exceeding amount of CO2 produced in the soil and released into the atmosphere, resulting from aerobic processes of mineralization of organic matter (excessive loosening) is considered to be not only a way of increasing the CO2 in the atmosphere, but also a loss of long-term soil fertility. By determining the humus content after 3 years, it can be observed an increasing tendency when applying the minimum tillage (the increase was up to 0.41%) and no-tillage systems tillage (the increase was up to 0.64%). Carbon sequestration in soil is net advantageous, improving the productivity and sustainability. The more the organic content in soil is higher the better soil aggregation is. The soil without organic content is compact. This reduces its capacity to infiltrate water, nutrients solubility and productivity, and that way it reduces the soil capacity for carbon sequestration. Acknowledgments This paper was performed under the frame of the Partnership in priority domains - PNII, developed with the support of MEN-UEFISCDI, project no. PN-II-PT-PCCA-2013-4-0015: Expert System for Risk Monitoring in Agriculture and Adaptation of Conservative Agricultural Technologies to Climate Change.

  15. Properties of 21 Urban Agricultural Soils in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Kim, J.; Kim, H. S.; Kim, J. W.

    2012-04-01

    The number of urban agriculture practitioners has been increasing rapidly in Korea like many other urbanized countries recently. The Korean government enacted a law for promoting urban agriculture in 2011. However, urban soil environment can be potential sources of many toxic contaminants including heavy metals making people concern about the safety of the agricultural products from the urban agriculture. The accumulation of heavy metals in soil and plant by overuse of compost from animal waste was one of the raised concerns. This study was carried out to find out properties and total and phytoavailable (1.0 M NH4NO3 extractable) contents of heavy metals (Cd, Pb, Cu, Zn) in 21 urban agricultural soils in Seoul. On the average, the investigated urban soils showed pH1:5 6.89, EC1:5 0.14 dS m-1, organic mater 2.22%, available P2O5 139 mg kg-1, cation exchange capacity (CEC) 11.36 cmolc kg-1 and total nitrogen 0.15%. The average exchangeable-Ca, -Mg, -K and -Na of the 21 samples were 6.71, 1.44, 1.06 and 0.30 cmol+ kg-1, respectively. Total heavy metal concentrations (Cd 0.97-3.17 mg kg-1, average 1.89 mg kg-1; Pb 8.10-46.27 mg kg-1, average 19.96 mg kg-1; Cu 8.97-133.40 mg kg-1, average 38.37 mg kg-1; and Zn 38.97-180.06 mg kg-1, average 97.73 mg kg-1) in urban agricultural soils were lower than those of the warning standard in the area 1 according to the Soil Environmental Conservation Act of Korea. Phytoavailable-Cu, -Pb, and -Zn concentrations of the samples showed 0.02-0.28, N.D-0.09 and 0.01-0.43 mg kg-1, respectively. Phytoavailable-Cd was not detected. The average phytoavailable-Cu concentration from this study was similar to that from the previous phytoavailable-Cu of the highly contaminated soils from nearby abandoned mines, which might be resulted from overuse of compost from animal waste. Results showed a necessity of long-term monitoring of soils for sustainable urban agriculture in Korea.

  16. Impact of bioenergy production on carbon storage and soil functions

    NASA Astrophysics Data System (ADS)

    Prays, Nadia; Franko, Uwe

    2016-04-01

    An important renewable energy source is methane produced in biogas plants (BGPs) that convert plant material and animal excrements to biogas and a residue (BGR). If the plant material stems from crops produced specifically for that purpose, a BGP have a 'footprint' that is defined by the area of arable land needed for the production of these energy crops and the area for distributing the BGRs. The BGR can be used to fertilize these lands (reducing the need for carbon and nitrogen fertilizers), and the crop land can be managed to serve as a carbon sink, capturing atmospheric CO2. We focus on the ecological impact of different BGPs in Central Germany, with a specific interest in the long-term effect of BGR-fertilization on carbon storage within the footprint of a BGP. We therefore studied nutrient fluxes using the CANDY (CArbon and Nitrogen Dynamics) model, which processes site-specific information on soils, crops, weather, and land management to compute stocks and fluxes of carbon and nitrogen for agricultural fields. We used CANDY to calculated matter fluxes within the footprints of BGPs of different sizes, and studied the effect of the substrate mix for the BGP on the carbon dynamics of the soil. This included the land requirement of the BGR recycling when used as a fertilizer: the footprint of a BGP required for the production of the energy crop generally differs from its footprint required to take up its BGR. We demonstrate how these findings can be used to find optimal cropping choices and land management for sustainable soil use, maintaining soil fertility and other soil functions. Furthermore, site specific potentials and limitations for agricultural biogas production can be identified and applied in land-use planning.

  17. Persistence and Viability of Lecanicillium lecanii in Chinese Agricultural Soil

    PubMed Central

    Peng, De-Liang; Zhou, Jie; Zhang, Xiao-Lin; Zhang, Zhao-Rong; Zhao, Jin-Jin; Wu, Yu-Huan

    2015-01-01

    The entomopathogenic fungus L. lecanii has been developed as biopesticides and used widely for biological control of several insects in agricultural practice. Due to the lack of isolation/count methods for L. lecanii in soil, the persistence of this fungus in soil appears to have attracted no attention. A selective medium and count method for L. lecanii in soil based on cetyl trimethyl ammonium bromide (CTAB) was developed, and then the persistence and viability of this fungus in soil were investigated under field conditions between 2012 and 2014. The results showed that the rate of recovery for L. lecanii in soil on the selective CTAB medium was satisfactory. The minimum CFUs for L. lecanii on the selective medium (0.5 g/L CTAB) was about 102 conidia/g soil. The L. lecanii density in soil declined quickly in the first month after inoculation with fungal conidia, kept stable for 6 to 10 months, and then decreased gradually until undetectable. L. lecanii could persist for at least 14 months in the agricultural soil of northern China. The colony growth, conidia yield and germination rate on plates, as well as the median lethal concentration or times (LC50 or LT50) to aphids, mycelium growth in aphids and sporulation on aphids of L. lecanii did not change significantly during the persistence in soil. In general, the count method developed here was a very useful tool for monitoring the dynamics of natural or introduced L. lecanii populations in soil, and the data on the persistence of L. lecanii in soil reported here were helpful for biological control and environmental risk assessment. PMID:26375030

  18. Variability of Total Below Ground Carbon Allocation amongst Common Agricultural Land Management Practices: a Case Study

    NASA Astrophysics Data System (ADS)

    Wacha, K. M.; Papanicolaou, T.; Wilson, C. G.

    2010-12-01

    Field measurements and numerical models are currently being used to estimate quantities of Total Belowground Carbon Allocation (TBCA) for three representative land uses, viz. corn, soybeans, and prairie bromegrass for CRP (Conservation Reserve Program) of an agricultural Iowa sub-watershed, located within the Clear Creek Watershed (CCW). Since it is difficult to measure TBCA directly, a mass balance approach has been implemented to estimate TBCA as follows: TBCA = FS + FE+ Δ(CS + CR + CL) - FA , where the term Fs denotes soil respiration; FE is the carbon content of the eroded/deposited soil; ΔCS, ΔCR, ΔCL denote the changes in carbon content of the mineral soil, plant roots, and litter layer, respectively; and FA is the above ground litter fall of dead plant material to the soil. The terms are hypothesized to have a huge impact on TBCA within agricultural settings due to intensive tillage practices, water-driven soil erosion/deposition, and high usage of fertilizer. To test our hypothesis, field measurements are being performed at the plot scale, replicating common agricultural land management practices. Soil respiration (FS) is being measured with an EGM-4 CO2 Gas Analyzer and SRC-1 Soil Respiration Chamber (PP Systems), soil moisture and temperature are recorded in the top 20 cm for each respective soil respiration measurement, and litter fall rates (FA) are acquired by collecting the residue in a calibrated pan. The change in carbon content of the soil (ΔCS), roots (ΔCR) and litter layer (ΔCL) are being analyzed by collecting soil samples throughout the life cycle of the plant. To determine the term FE for the three representative land management practices, a funnel collection system located at the plot outlet was used for collecting the eroded material after natural rainfall events. Field measurements of TBCA at the plot scale via the mass balance approach are used to calibrate the numerical agronomic process model DAYCENT, which simulates the daily

  19. Is current biochar soil study addressing global soil constraints for sustainable agriculture?

    NASA Astrophysics Data System (ADS)

    Pan, Genxing; Zhang, Dengxiao; Yan, Ming; Niu, Yaru; Liu, Xiaoyu; van Zwieten, Lukas; Chen, De; Bian, Rongjun; Cheng, Kun; Li, Lianqing; Joseph, Stephen; Zheng, Jinwei; Zhang, Xuhui; Zheng, Jufeng; Crowley, David; Filley, Timothy

    2016-04-01

    Global soil degradation has been increasingly threatened sustainability of world agriculture. Use of biochar from bio-wastes has been proposed as a global option for its great potential in tackling soil degradation and mitigating climate change in agriculture. For last 10 years, there have been greatly increasing interests in application of charred biomass, more recently termed biochar, as a soil amendment for addressing soil constraints for sustainable agriculture. Biochar soil studies could deliver reliable information for appropriate application of biochar to soils where for sustainable agriculture has been challenged. Here we review the literature of 798 publications reporting biochar soil studies by August, 2015 to address potential gaps in understanding of biochar's role in agriculture. We have found some substantial biases and gaps inherent in the current biochar studies. 1) The majority of published studies were from developed regions where the soils are less constrained and were much more frequent in laboratory and glasshouse pot experiments than field studies under realistic agriculture. 2) The published biochar soil studies have used more often small kiln or lab prepared biochar than commercial scale biochars, more often wood and municipal waste derived biochars than crop straw biochars. Overall, the lack of long-term well designed field studies using biochar produced in commercial processes may have limited our current understanding of biochar's potential to enhance global crop production and climate change mitigation. We have also recommended a global alliance between longer-term research experiments and biochar production facilities to foster the uptake of this important technology at a global scale. Keywords: biochar, soil study, literature review, research gap, global perspective, quantitative assessment, sustainable agriculture

  20. Soil carbon changes for bioenergy crops.

    SciTech Connect

    Andress, D.

    2004-04-22

    Bioenergy crops, which displace fossil fuels when used to produce ethanol, biobased products, and/or electricity, have the potential to further reduce atmospheric carbon levels by building up soil carbon levels, especially when planted on lands where these levels have been reduced by intensive tillage. The purpose of this study is to improve the characterization of the soil carbon (C) sequestration for bioenergy crops (switchgrass, poplars, and willows) in the Greenhouse gases, Regulated Emissions, and Energy Use in Transportation (GREET) model (Wang 1999) by using the latest results reported in the literature and by Oak Ridge National Laboratory (ORNL). Because soil carbon sequestration for bioenergy crops can play a significant role in reducing greenhouse gas (GHG) emissions for cellulosic ethanol, it is important to periodically update the estimates of soil carbon sequestration from bioenergy crops as new and better data become available. We used the three-step process described below to conduct our study.

  1. Fate of the nonsteroidal anti-inflammatory drug naproxen in agricultural soil receiving liquid municipal biosolids.

    PubMed

    Topp, Edward; Hendel, John G; Lapen, David R; Chapman, Ralph

    2008-10-01

    Naproxen (2-(6-methoxy-2-naphthyl) propionic acid) is widely used for the treatment of pain and swelling associated with arthritis, gout, and other inflammatory conditions. Naproxen has been detected in municipal sewage outflows and in surface waters and could reach agricultural land through the application of municipal biosolids or reclaimed water. The persistence characteristics of naproxen in three agricultural soils were investigated. In laboratory microcosms of moist soil incubated at 30 degrees C, [O-14CH3]naproxen was rapidly and thoroughly mineralized to 14CO2 with comparable kinetics in a sandy loam soil, a loam soil, and a silt loam soil. Naproxen mineralization was responsive to soil temperature and soil moisture content, consistent with the primary mechanism of dissipation being biodegradation. Mineralization of naproxen was hastened by the addition of liquid municipal biosolids (LMBs) from a municipal sewage treatment plant that aerated this material. Naproxen was stable in autoclaved soils with or without addition of autoclaved LMBs, whereas naproxen was rapidly mineralized in sterile soil supplemented with nonsterile LMBs. An enrichment culture was obtained from aerobically digested LMBs in a mineral salts medium with naproxen as the sole source of carbon. The culture converted the parent compound to the corresponding naphthol, O-desmethyl naproxen. In summary, naproxen was rapidly removed from soil, with mesophilic aerobic biodegradation being the primary mechanism of dissipation. Microorganisms carried in biosolids enhanced naproxen dissipation in soil, with the initial mechanism of attack likely being O-demethylation. We conclude on this basis that naproxen in soils receiving biosolids would be readily biodegradable and, in the absence of preferential flow or runoff, pose little risk for contamination of adjacent water or crops. PMID:18419173

  2. Soil salinity decreases global soil organic carbon stocks.

    PubMed

    Setia, Raj; Gottschalk, Pia; Smith, Pete; Marschner, Petra; Baldock, Jeff; Setia, Deepika; Smith, Jo

    2013-11-01

    Saline soils cover 3.1% (397 million hectare) of the total land area of the world. The stock of soil organic carbon (SOC) reflects the balance between carbon (C) inputs from plants, and losses through decomposition, leaching and erosion. Soil salinity decreases plant productivity and hence C inputs to the soil, but also microbial activity and therefore SOC decomposition rates. Using a modified Rothamsted Carbon model (RothC) with a newly introduced salinity decomposition rate modifier and a plant input modifier we estimate that, historically, world soils that are currently saline have lost an average of 3.47 tSOC ha(-1) since they became saline. With the extent of saline soils predicted to increase in the future, our modelling suggests that world soils may lose 6.8 Pg SOC due to salinity by the year 2100. Our findings suggest that current models overestimate future global SOC stocks and underestimate net CO2 emissions from the soil-plant system by not taking salinity effects into account. From the perspective of enhancing soil C stocks, however, given the lower SOC decomposition rate in saline soils, salt tolerant plants could be used to sequester C in salt-affected areas.

  3. Electrokinetic treatment of an agricultural soil contaminated with heavy metals.

    PubMed

    Figueroa, Arylein; Cameselle, Claudio; Gouveia, Susana; Hansen, Henrik K

    2016-07-28

    The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen.

  4. Electrokinetic treatment of an agricultural soil contaminated with heavy metals.

    PubMed

    Figueroa, Arylein; Cameselle, Claudio; Gouveia, Susana; Hansen, Henrik K

    2016-07-28

    The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen. PMID:27127923

  5. European GEMAS mapping of agricultural soils: Arsenic results

    NASA Astrophysics Data System (ADS)

    Tarvainen, Timo; Reimann, Clemens; Albanese, Stefano; Birke, Manfred; Poňavič, Michal; Ladenberger, Anna

    2014-05-01

    The GEMAS data set provides a homogenised overview of arsenic distribution in agricultural (Ap horizon, 0-20 cm) and grazing land soil (Gr, 0-10 cm) of Europe. The GEMAS mapping project covers western Europe at a sample density of 1 site/2500 km2. Arsenic concentrations are reported for the

  6. Plumbum contamination detecting model for agricultural soil using hyperspectral data

    NASA Astrophysics Data System (ADS)

    Liu, Xiangnan; Huang, Fang; Wang, Ping

    2008-10-01

    The issue of environmental pollution due to toxic heavy metals in agricultural land has caused worldwide growing concern in recent years. Being one of toxic heavy metals, the accumulation of Plumbum (Pb) may have negative effects on natural and agricultural vegetation growth, yield and quality. It can also constitute short-term and long-term health risks by entering the food chain. In this study, we analyze the relationships between physical and chemical characteristics, biological parameters of soil-vegetation system and hyperspectral spectrum responses systematically. The relation between hyperspectral data and the biological parameters of Pb polluted wheat canopy such as leaf pigments, leaf moisture, cell structure and leaf area index (LAI) are discussed. We detect the changes in the wheat biological parameters and spectral response associated with Pb concentration in soil. To reveal the impact mechanisms of Pb concentration on agricultural soil, six models including chlorophyll-leaf moisture model, chlorophyll-cell structure model, chlorophyll-LAI model, leaf moisture-cell structure model, leaf moisture-LAI model, cell structure- LAI model are explored. We find that changes in Pb concentration present various features in different models. Pb contamination in agricultural soil can be identified and assessed effectively while integrating the characteristics of those developed models.

  7. Phosphorus leaching from agricultural soils of the Delmarva Peninsula, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaching of phosphorus (P) mobilizes edaphic and applied sources of P and is a primary pathway of concern in agricultural soils of the Delmarva Peninsula, which defines the eastern boundary of the eutrophic Chesapeake Bay. We evaluated P leaching before and after poultry litter application from inta...

  8. Sequestration of Soil Carbon as Secondary Carbonates (Invited)

    NASA Astrophysics Data System (ADS)

    Lal, R.

    2013-12-01

    Rattan Lal Carbon Management and Sequestration Center The Ohio State University Columbus, OH 43210 USA Abstract World soils, the major carbon (C) reservoir among the terrestrial pools, contain soil organic C (SOC) and soil inorganic C (SIC). The SIC pool is predominant in soils of arid and semi-arid regions. These regions cover a land area of about 4.9x109 ha. The SIC pool in soils containing calcic and petrocalcic horizons is estimated at about 695-748 Pg (Pg = 1015 g = 1 gigaton) to 1-m depth. There are two types of carbonates. Lithogenic or primary carbonates are formed from weathering of carbonaceous rocks. Pedogenic or secondary carbonates are formed by dissolution of CO2 in the soil air to form carbonic acid and precipitation as carbonates of Ca+2 or Mg+2. It is the availability of Ca+2 or Mg+2 from outside the ecosystem that is essential to sequester atmospheric CO2. Common among outside sources of Ca+2 or Mg+2 are irrigation water, aerial deposition, sea breeze, fertilizers, manure and other amendments. The decomposition of SOC and root respiration may increase the partial pressure of CO2 in the soil air and lead to the formation of HCO_3^- upon dissolution in H20. Precipitation of secondary carbonates may result from decreased partial pressure of CO2 in the sub-soil, increased concentration of Ca+2, Mg+2 and HCO_3^- in soil solution, and decreased soil moisture content by evapotranspiration. Transport of bicarbonates in irrigated soils and subsequent precipitation above the ground water (calcrete), activity of termites and other soil fauna, and management of urban soils lead to formation of secondary carbonates. On a geologic time scale, weathering of silicate minerals and transport of the by-products into the ocean is a geological process of sequestration of atmospheric CO2. Factors affecting formation of secondary carbonates include land use, and soil and crop management including application of biosolids, irrigation and the quality of irrigation water

  9. Agricultural use of soil, consequences in soil organic matter and hydraulic conductivity compared with natural vegetation in central Spain

    NASA Astrophysics Data System (ADS)

    Vega, Verónica; Carral, Pilar; Alvarez, Ana Maria; Marques, Maria Jose

    2014-05-01

    When ecosystems are under pressure due to high temperatures and water scarcity, the use of land for agriculture can be a handicap for soil and water conservation. The interactions between plants and soils are site-specific. This study provides information about the influence of the preence vs. The absence of vegetation on soil in a semi-arid area of the sout-east of Madrid (Spain, in the Tagus River basin. In this area soil materials are developed over a calcareous-evaporitic lithology. Soils can be classified as Calcisols, having horizons of accumulation with powdered limestone and irregular nodules of calcium carbonate. They can be defined as Haplic Cambisols and Leptic Calcisols (WRB 2006-FAO). The area is mainly used for rainfed agriculture, olive groves, vineyards and cereals. There are some patches of bushes (Quercus sp.) and grasses (Stipa tenacissima L.) although only found on the top of the hills. This study analyses the differences found in soils having three different covers: Quercus coccifera, Stipa tenacissima and lack of vegetation. This last condition was found in the areas between cultivated olive trees. Soil organic matter, porosity and hydraulic conductivity are key properties of soil to understand its ability to adapt to climate or land use changes. In order to measure the influence of different soil covers, four replicates of soil were sampled in each condition at two soil depth, (0-10 cm and 10-20 cm). Hydraulic conductivity was measured in each soil condition and replicate using a Mini-disk® infiltrometer. There were no differences between the two depths sampled. Similarly, there were no changes in electric conductivity (average 0.1±0.03 dS m-1); pH (8.7±0.2) or calcium carbonate content (43±20 %). Nevertheless, significant differences (p>0.001) were found in soil organic matter. The maximum was found in soils under Quercus (4.7±0.5 %), followed by Stipa (2.2±1.1 %). The soil without vegetation in the areas between olive trees had only 0

  10. Mississippi Basin Carbon Project: upland soil database for sites in Nishnabotna River basin, Iowa

    USGS Publications Warehouse

    Harden, J.W.; Fries, T.L.; Haughy, R.; Kramer, L.; Zheng, Shuhui

    2001-01-01

    The conversion of land from its native state to an agricultural use commonly results in a significant loss of soil carbon (Mann, 1985; Davidson and Ackerman, 1993). Globally, this loss is estimated to account for as much as 1/3 of the net CO2 emissions for the period of 1850 to 1980 (Houghton and others, 1983). Roughly 20 to 40 percent of original soil carbon is estimated to be lost as CO2 as a result of agricultural conversion, or "decomposition enhancement". Global models use this estimate along with land conversion data to provide agricultural contributions of CO2 emissions for global carbon budgets (Houghton and others, 1983; Schimel, 1995). Soil erosion rates are significantly (10X) higher on croplands than on their undisturbed equivalents (Dabney and others, 1997). Most of the concern over erosion is related to diminished productivity of the uplands (Stallings, 1957; McGregor and others, 1969; Rhoton, 1990) or to increased hazards and navigability of the lowlands in the late 1800's to early 1900's. Yet because soil carbon is concentrated at the soil surface, with an exponential decline in concentration with depth (Harden et al, 1999), it is clear that changes in erosion rates seen on croplands must also impact soil carbon storage and terrestrial carbon budgets as well. As yet, erosional losses of carbon are not included in global carbon budgets explicitly as a factor in land conversion nor implicitly as a portion of the decomposition enhancement. However, recent work by Lal and others (1995) and by Stallard (1998) suggests that significant amounts of eroded soil may be stored in man-made reservoirs and depositional environments as a result of agricultural conversion. Moreover, Stallard points out that eroding soils have the potential for replacing part of the carbon trapped in man-made reservoirs. If true, then the global carbon budget may grossly underestimate or ignore a significant sink term resulting from the burial of eroded soil.

  11. Mississippi Basin Carbon Project; upland soil database for sites in Yazoo Basin, northern Mississippi

    USGS Publications Warehouse

    Harden, J.W.; Fries, T.L.; Huntington, T.G.

    1999-01-01

    The conversion of land from its native state to an agricultural use commonly results in a significant loss of soil carbon (Mann, 1985; Davidson and Ackerman, 1993). Globally, this loss is estimated to account for as much as 1/3 of the net CO2 emissions for the period of 1850 to 1980 (Houghton et al, 1983). Roughly 20 to 40 percent of original soil carbon is estimated to be lost as CO2 as a result of agricultural conversion, or 'decomposition enhancement', and global models use this estimate along with land conversion data to provide agricultural contributions of CO2 emissions for global carbon budgets (Houghton and others, 1983; Schimel, 1995). As yet, erosional losses of carbon are not included in global carbon budgets explicitly as a factor in land conversion nor implicitly as a portion of the decomposition enhancement. However, recent work by Lal et al (1995) and by Stallard (1998) suggests that significant amounts of eroded soil may be stored in man-made reservoirs and depositional environments as a result of agricultural conversion. Moreover, Stallard points out that if eroding soils have the potential for replacing part of the carbon trapped in man-made reservoirs, then the global carbon budget may grossly underestimate or ignore a significant sink term resulting from the burial of eroded soil. Soil erosion rates are significantly (10X) higher on croplands than on their undisturbed equivalents (Dabney et al, 1997). Most of the concern over erosion is related to diminished productivity of the uplands (Stallings, 1957; McGregor et al, 1993; Rhoton and Tyler, 1990) or to increased hazards and navigability of the lowlands in the late 1800's to early 1900's. Yet because soil carbon is concentrated at the soil surface, with an exponential decline in concentration with depth, it is clear that changes in erosion rates seen on croplands must also impact soil carbon storage and terrestrial carbon budgets as well.

  12. Greater carbon stocks and faster turnover rates with increasing agricultural productivity

    NASA Astrophysics Data System (ADS)

    Sanderman, J.; Fallon, S.; Baisden, T. W.

    2013-12-01

    H.H. Janzen (2006) eloquently argued that from an agricultural perspective there is a tradeoff between storing carbon as soil organic matter (SOM) and the soil nutrient and energy benefit provided during SOM mineralization. Here we report on results from the Permanent Rotation Trial at the Waite Agricultural Institute, South Australia, indicating that shifting to an agricultural management strategy which returns more carbon to the soil, not only leads to greater carbon stocks but also increases the rate of carbon cycling through the soil. The Permanent Rotation Trial was established on a red Chromosol in 1925 with upgrades made to several treatments in 1948. Decadal soil samples were collected starting in 1963 at two depths, 0-10 and 10-22.5 cm, by compositing 20 soil cores taken along the length of each plot. We have chosen to analyze five trials representing a gradient in productivity: permanent pasture (Pa), wheat-pasture rotation (2W4Pa), continuous wheat (WW), wheat-oats-fallow rotation (WOF) and wheat-fallow (WF). For each of the soil samples (40 in total), the radiocarbon activity in the bulk soil as well as size-fractionated samples was measured by accelerator mass spectrometry at ANU's Radiocarbon Dating Laboratory (Fallon et al. 2010). After nearly 70 years under each rotation, SOC stocks increased linearly with productivity data across the trials from 24 to 58 tC ha-1. Importantly, these differences were due to greater losses over time in the low productivity trials rather than gains in SOC in any of the trials. Uptake of the bomb-spike in atmospheric 14C into the soil was greatest in the trials with the greatest productivity. The coarse size fraction always had greater Δ14C values than the bulk soil samples. Several different multi-pool steady state and non-steady state models were used to interpret the Δ14C data in terms of SOC turnover rates. Regardless of model choice, either the decay rates of all pools needed to increase or the allocation of C to

  13. Fate of the antiretroviral drug tenofovir in agricultural soil.

    PubMed

    Al-Rajab, Abdul Jabbar; Sabourin, Lyne; Chapman, Ralph; Lapen, David R; Topp, Edward

    2010-10-15

    Tenofovir (9-(R)-(2-phosphonylmethoxypropyl)-adenine) is an antiretroviral drug widely used for the treatment of human immunodeficiency virus (HIV-1) and Hepatitis B virus (HBV) infections. Tenofovir is extensively and rapidly excreted unchanged in the urine. In the expectation that tenofovir could potentially reach agricultural lands through the application of municipal biosolids or wastewater, and in the absence of any environmental fate data, we evaluated its persistence in selected agricultural soils. Less than 10% of [adenine-8-(14)C]-tenofovir added to soils varying widely in texture (sand, loam, clay loam) was mineralized in a 2-month incubation under laboratory conditions. Tenofovir was less readily extractable from clay soils than from a loam or a sandy loam soil. Radioactive residues of tenofovir were removed from the soil extractable fraction with DT(50)s ranging from 24±2 to 67+22days (first order kinetic model) or 44+9 to 127+55days (zero order model). No extractable transformation products were detectable by HPLC. Tenofovir mineralization in the loam soil increased with temperature (range 4°C to 30°C), and did not occur in autoclaved soil, suggesting a microbial basis. Mineralization rates increased with soil moisture content, ranging from air-dried to saturated. In summary, tenofovir was relatively persistent in soils, there were no extractable transformation products detected, and the response of [adenine-8-(14)C]-tenofovir mineralization to soil temperature and heat sterilization indicated that the molecule was biodegraded by aerobic microorganisms. Sorption isotherms with dewatered biosolids suggested that tenofovir residues could potentially partition into the particulate fraction during sewage treatment. PMID:20800877

  14. Cycling of beryllium and carbon through hillslope soils in Iowa

    USGS Publications Warehouse

    Harden, J.W.; Fries, T.L.; Pavich, M.J.

    2002-01-01

    Isotopes of Be and C were used to reconstruct loess accumulation, hillslope evolution, and agricultural modification in soils of western Iowa. While both elements are derived from additions by the atmosphere (via plants in the case of carbon), the differences in element cycling allow erosional and depositional processes to be separated from biochemical processing. Based on 10Be, loess accumulation likely occurred simultaneously with hillslope degradation. Rates of loess accumulation declined five-fold between early stages (late Pleistocene and early Holocene) and later stages (late Holocene) of accumulation, but the absolute timing of accumulation requires independent dating methods. Based on 14C measurements, plant inputs and decomposition are significant near the surface, but below 1-1.5 m carbon inputs are minimal and decomposition is nearly arrested. The amount of carbon below 1.5 m is constant (0.1%) and is composed of soil organic matter that was buried by loess. Agricultural modification results in a dramatic redistribution of 10Be through soil erosion and deposition. By contrast, the redistribution of soil organic matter is masked by the rapid cycling of C through the topsoil as it continually decomposes and is replaced by plant inputs.

  15. Barley seedling growth in soils amended with fly ash or agricultural lime followed by acidification

    SciTech Connect

    Renken, R.R.; McCallister, D.L.; Tarkalson, D.D.; Hergert, G.W.; Marx, D.B.

    2006-05-15

    Calcium-rich coal combustion fly ash can be used as an amendment to neutralize soil acidity because of its oxides and carbonate content, but its aluminum content could inhibit plant growth if soil pH values fall below optimal agronomic levels. This study measured root and shoot growth of an acid-sensitive barley (Hordeum vulgare L. 'Kearney') grown in the greenhouse on three naturally acid soils. The soils were either untreated or amended with various liming materials (dry fly ash, wet fly ash, and agricultural lime) at application rates of 0, .5, 1, and 1.5 times the recommended lime requirement, then treated with dilute acid solutions to simulate management-induced acidification. Plant growth indexes were measured at 30 days after planting. Root mass per plant and root length per plant were greater for the limed treatments than in the acidified check. Root growth in the limed treatments did not differ from root growth in the original nonacidified soils. Top mass per plant in all limed soils was either larger than or not different from that in the original nonacidified soils. Based on top mass per plant, no liming material or application rate was clearly superior. Both fly ash and agricultural lime reduced the impact of subsequent acidification on young barley plants. Detrimental effects of aluminum release on plant growth were not observed. Calcium-rich fly ash at agronomic rates is an acceptable acid-neutralizing material with no apparent negative effects.

  16. Long-term fate of nitrate fertilizer in agricultural soils.

    PubMed

    Sebilo, Mathieu; Mayer, Bernhard; Nicolardot, Bernard; Pinay, Gilles; Mariotti, André

    2013-11-01

    Increasing diffuse nitrate loading of surface waters and groundwater has emerged as a major problem in many agricultural areas of the world, resulting in contamination of drinking water resources in aquifers as well as eutrophication of freshwaters and coastal marine ecosystems. Although empirical correlations between application rates of N fertilizers to agricultural soils and nitrate contamination of adjacent hydrological systems have been demonstrated, the transit times of fertilizer N in the pedosphere-hydrosphere system are poorly understood. We investigated the fate of isotopically labeled nitrogen fertilizers in a three-decade-long in situ tracer experiment that quantified not only fertilizer N uptake by plants and retention in soils, but also determined to which extent and over which time periods fertilizer N stored in soil organic matter is rereleased for either uptake in crops or export into the hydrosphere. We found that 61-65% of the applied fertilizers N were taken up by plants, whereas 12-15% of the labeled fertilizer N were still residing in the soil organic matter more than a quarter century after tracer application. Between 8-12% of the applied fertilizer had leaked toward the hydrosphere during the 30-y observation period. We predict that additional exports of (15)N-labeled nitrate from the tracer application in 1982 toward the hydrosphere will continue for at least another five decades. Therefore, attempts to reduce agricultural nitrate contamination of aquatic systems must consider the long-term legacy of past applications of synthetic fertilizers in agricultural systems and the nitrogen retention capacity of agricultural soils.

  17. Agricultural management practices to sustain crop yields and improve soil and environmental qualities.

    PubMed

    Sainju, Upendra M; Whitehead, Wayne F; Singh, Bharat P

    2003-08-20

    In the past several decades, agricultural management practices consisting of intensive tillage and high rate of fertilization to improve crop yields have resulted in the degradation of soil and environmental qualities by increasing erosion and nutrient leaching in the groundwater and releasing greenhouses gases, such as carbon dioxide (CO2) and nitrous oxide (N2O), that cause global warming in the atmosphere by oxidation of soil organic matter. Consequently, management practices that sustain crop yields and improve soil and environmental qualities are needed. This paper reviews the findings of the effects of tillage practices, cover crops, and nitrogen (N) fertilization rates on crop yields, soil organic carbon (C) and N concentrations, and nitrate (NO3)-N leaching from the soil. Studies indicate that conservation tillage, such as no-till or reduced till, can increase soil organic C and N concentrations at 0- to 20-cm depth by as much as 7-17% in 8 years compared with conventional tillage without significantly altering crop yields. Similarly, cover cropping and 80-180 kg N ha(-1) year(-1) fertilization can increase soil organic C and N concentrations by as much as 4-12% compared with no cover cropping or N fertilization by increasing plant biomass and amount of C and N inputs to the soil. Reduced till, cover cropping, and decreased rate of N fertilization can reduce soil N leaching compared with conventional till, no cover cropping, and full rate of N fertilization. Management practices consisting of combinations of conservation tillage, mixture of legume and nonlegume cover crops, and reduced rate of N fertilization have the potentials for sustaining crop yields, increasing soil C and N storage, and reducing soil N leaching, thereby helping to improve soil and water qualities. Economical and social analyses of such practices are needed to find whether they are cost effective and acceptable to the farmers.

  18. Microbial Community Structure and Enzyme Activities in Semiarid Agricultural Soils

    NASA Astrophysics Data System (ADS)

    Acosta-Martinez, V. A.; Zobeck, T. M.; Gill, T. E.; Kennedy, A. C.

    2002-12-01

    The effect of agricultural management practices on the microbial community structure and enzyme activities of semiarid soils of different textures in the Southern High Plains of Texas were investigated. The soils (sandy clay loam, fine sandy loam and loam) were under continuous cotton (Gossypium hirsutum L.) or in rotations with peanut (Arachis hypogaea L.), sorghum (Sorghum bicolor L.) or wheat (Triticum aestivum L.), and had different water management (irrigated or dryland) and tillage (conservation or conventional). Microbial community structure was investigated using fatty acid methyl ester (FAME) analysis by gas chromatography and enzyme activities, involved in C, N, P and S cycling of soils, were measured (mg product released per kg soil per h). The activities of b-glucosidase, b-glucosaminidase, alkaline phosphatase, and arylsulfatase were significantly (P<0.05) increased in soils under cotton rotated with sorghum or wheat, and due to conservation tillage in comparison to continuous cotton under conventional tillage. Principal component analysis showed FAME profiles of these soils separated distinctly along PC1 (20 %) and PC2 (13 %) due to their differences in soil texture and management. No significant differences were detected in FAME profiles due to management practices for the same soils in this sampling period. Enzyme activities provide early indications of the benefits in microbial populations and activities and soil organic matter under crop rotations and conservation tillage in comparison to the typical practices in semiarid regions of continuous cotton and conventional tillage.

  19. Biochar application to sandy and loamy soils for agricultural nutrient management

    NASA Astrophysics Data System (ADS)

    Gronwald, Marco; Don, Axel; Tiemeyer, Baerbel; Helfrich, Mirjam

    2014-05-01

    Soil fertility of agricultural soils is challenged by nutrients losses and increasing soil acidification. Furthermore, leached nutrients negatively affect the quality of ground and surface water 1]. In addition to the possible soil carbon sequestration by applying biochars, many positive soil-improving properties are attributed to biochars. The application of biochars to agricultural - especially sandy - soils could reduce leaching of nutrients and may improve their availability 1,2]. Thus, biochar application to agricultural fields could be an ecologically and economically viable option to improve soils' fertility. However, biochar properties strongly depend on their feedstock and production process 3]. Various types of biochars (pyrolysis char, hydrochar (produced at 200 and 250° C); feedstocks: digestate, Miscanthus and wood chips) were used to determine sorption kinetics and sorption isotherms for the major nutrients Ca, Mg, K, NH4 and NO3 as a function of biochar types in different soil substrates (sand, loess). In addition, the biochars were washed to create free binding sites on the chars' surface that simulate aged char. We compared the simulated aged char with biochars that was aged in-situ at a field experiment for seven months. The first results showed that pyrochars have the largest retention potential for NO3 and hydrochars have retention potential for NH4. Washing of biochars turned them from a PO4 and NH4 source into an adsorber, especially for hydrochars. Highest leaching was observed for biochars from digestates likely due to the high nutrient content of digestates. But the different ions may lead to pH-dependent interactions between each other and the chars' surface that override the adsoption effects. In this context, cation-bridge and ligand bindings 4,5] need to be further investigated. Most of the fresh, unwashed biochars were a source of nutrients with hardly any detectable nutrient retention. Pyrochars showed the highest potential for anion

  20. Observation of soil moisture variability in agricultural and grassland field soils using a wireless sensor network

    NASA Astrophysics Data System (ADS)

    Priesack, Eckart; Schuh, Max

    2014-05-01

    Soil moisture dynamics is a key factor of energy and matter exchange between land surface and atmosphere. Therefore long-term observation of temporal and spatial soil moisture variability is important in studying impacts of climate change on terrestrial ecosystems and their possible feedbacks to the atmosphere. Within the framework of the network of terrestrial environmental observatories TERENO we installed at the research farm Scheyern in soils of two fields (of ca. 5 ha size each) the SoilNet wireless sensor network (Biogena et al. 2010). The SoilNet in Scheyern consists of 94 sensor units, 45 for the agricultural field site and 49 for the grassland site. Each sensor unit comprises 6 SPADE sensors, two sensors placed at the depths 10, 30 and 50 cm. The SPADE sensor (sceme.de GmbH, Horn-Bad Meinberg Germany) consists of a TDT sensor to estimate volumetric soil water content from soil electrical permittivity by sending an electromagnetic signal and measuring its propagation time, which depends on the soil dielectric properties and hence on soil water content. Additionally the SPADE sensor contains a temperature sensor (DS18B20). First results obtained from the SoilNet measurements at both fields sites will be presented and discussed. The observed high temporal and spatial variability will be analysed and related to agricultural management and basic soil properties (bulk density, soil texture, organic matter content and soil hydraulic characteristics).

  1. Tightly-Coupled Plant-Soil Nitrogen Cycling: Comparison of Organic Farms across an Agricultural Landscape.

    PubMed

    Bowles, Timothy M; Hollander, Allan D; Steenwerth, Kerri; Jackson, Louise E

    2015-01-01

    How farming systems supply sufficient nitrogen (N) for high yields but with reduced N losses is a central challenge for reducing the tradeoffs often associated with N cycling in agriculture. Variability in soil organic matter and management of organic farms across an agricultural landscape may yield insights for improving N cycling and for evaluating novel indicators of N availability. We assessed yields, plant-soil N cycling, and root expression of N metabolism genes across a representative set of organic fields growing Roma-type tomatoes (Solanum lycopersicum L.) in an intensively-managed agricultural landscape in California, USA. The fields spanned a three-fold range of soil carbon (C) and N but had similar soil types, texture, and pH. Organic tomato yields ranged from 22.9 to 120.1 Mg ha-1 with a mean similar to the county average (86.1 Mg ha-1), which included mostly conventionally-grown tomatoes. Substantial variability in soil inorganic N concentrations, tomato N, and root gene expression indicated a range of possible tradeoffs between yields and potential for N losses across the fields. Fields showing evidence of tightly-coupled plant-soil N cycling, a desirable scenario in which high crop yields are supported by adequate N availability but low potential for N loss, had the highest total and labile soil C and N and received organic matter inputs with a range of N availability. In these fields, elevated expression of a key gene involved in root N assimilation, cytosolic glutamine synthetase GS1, confirmed that plant N assimilation was high even when inorganic N pools were low. Thus tightly-coupled N cycling occurred on several working organic farms. Novel combinations of N cycling indicators (i.e. inorganic N along with soil microbial activity and root gene expression for N assimilation) would support adaptive management for improved N cycling on organic as well as conventional farms, especially when plant-soil N cycling is rapid.

  2. [Soil organic carbon fractionation methods and their applications in farmland ecosystem research: a review].

    PubMed

    Zhang, Guo; Cao, Zhi-ping; Hu, Chan-juan

    2011-07-01

    Soil organic carbon is of heterogeneity in components. The active components are sensitive to agricultural management, while the inert components play an important role in carbon fixation. Soil organic carbon fractionation mainly includes physical, chemical, and biological fractionations. Physical fractionation is to separate the organic carbon into active and inert components based on the density, particle size, and its spatial distribution; chemical fractionation is to separate the organic carbon into various components based on the solubility, hydrolizability, and chemical reactivity of organic carbon in a variety of extracting agents. In chemical fractionation, the dissolved organic carbon is bio-available, including organic acids, phenols, and carbohydrates, and the acid-hydrolyzed organic carbon can be divided into active and inert organic carbons. Simulated enzymatic oxidation by using KMnO4 can separate organic carbon into active and non-active carbon. Biological fractionation can differentiate microbial biomass carbon and potential mineralizable carbon. Under different farmland management practices, the chemical composition and pool capacity of soil organic carbon fractions will have different variations, giving different effects on soil quality. To identify the qualitative or quantitative relationships between soil organic carbon components and carbon deposition, we should strengthen the standardization study of various fractionation methods, explore the integrated application of different fractionation methods, and sum up the most appropriate organic carbon fractionation method or the appropriate combined fractionation methods for different farmland management practices. PMID:22007474

  3. Strategies for soil-based precision agriculture in cotton

    NASA Astrophysics Data System (ADS)

    Neely, Haly L.; Morgan, Cristine L. S.; Stanislav, Scott; Rouze, Gregory; Shi, Yeyin; Thomasson, J. Alex; Valasek, John; Olsenholler, Jeff

    2016-05-01

    The goal of precision agriculture is to increase crop yield while maximizing the use efficiency of farm resources. In this application, UAV-based systems are presenting agricultural researchers with an opportunity to study crop response to environmental and management factors in real-time without disturbing the crop. The spatial variability soil properties, which drive crop yield and quality, cannot be changed and thus keen agronomic choices with soil variability in mind have the potential to increase profits. Additionally, measuring crop stress over time and in response to management and environmental conditions may enable agronomists and plant breeders to make more informed decisions about variety selection than the traditional end-of-season yield and quality measurements. In a previous study, seed-cotton yield was measured over 4 years and compared with soil variability as mapped by a proximal soil sensor. It was found that soil properties had a significant effect on seed-cotton yield and the effect was not consistent across years due to different precipitation conditions. However, when seed-cotton yield was compared to the normalized difference vegetation index (NDVI), as measured using a multispectral camera from a UAV, predictions improved. Further improvement was seen when soil-only pixels were removed from the analysis. On-going studies are using UAV-based data to uncover the thresholds for stress and yield potential. Long-term goals of this research include detecting stress before yield is reduced and selecting better adapted varieties.

  4. Phosphorus leaching from agricultural soils of the delmarva peninsula, USA.

    PubMed

    Kleinman, Peter J A; Church, Clinton; Saporito, Lou S; McGrath, Josh M; Reiter, Mark S; Allen, Arthur L; Tingle, Shawn; Binford, Greg D; Han, Kun; Joern, Brad C

    2015-03-01

    Leaching of phosphorus (P) mobilizes edaphic and applied sources of P and is a primary pathway of concern in agricultural soils of the Delmarva Peninsula, which defines the eastern boundary of the eutrophic Chesapeake Bay. We evaluated P leaching before and after poultry litter application from intact soil columns (30 cm diameter × 50 cm depth) obtained from low- and high-P members of four dominant Delmarva Peninsula soils. Surface soil textures ranged from fine sand to silt loam, and Mehlich-3 soil P ranged from 64 to 628 mg kg. Irrigation of soil columns before litter application pointed to surface soil P controls on dissolved P in leachate (with soil P sorption saturation providing a stronger relationship than Mehlich-3 P); however, strong relationships between P in the subsoil (45-50 cm) and leachate P concentrations were also observed ( = 0.61-0.73). After poultry litter application (4.5 Mg ha), leachate P concentrations and loads increased significantly for the finest-textured soils, consistent with observations that well-structured soils have the greatest propensity to transmit applied P. Phosphorus derived from poultry litter appeared to contribute 41 and 76% of total P loss in leachate from the two soils with the finest textures. Results point to soil P, including P sorption saturation, as a sound metric of P loss potential in leachate when manure is not an acute source of P but highlight the need to factor in macropore transport potential to predict leaching losses from applied P sources. PMID:26023971

  5. Adsorption and degradation of five selected antibiotics in agricultural soil.

    PubMed

    Pan, Min; Chu, L M

    2016-03-01

    Large quantities of antibiotics are being added to agricultural fields worldwide through the application of wastewater, manures and biosolids, resulting in antibiotic contamination and elevated environmental risks in terrestrial environments. Most studies on the environmental fate of antibiotics focus on aquatic environments or wastewater treatment plants. Little is known about the behavior of antibiotics at environmentally relevant concentrations in agricultural soil. In this study we evaluated the adsorption and degradation of five different antibiotics (tetracycline, sulfamethazine, norfloxacin, erythromycin, and chloramphenicol) in sterilized and non-sterilized agricultural soils under aerobic and anaerobic conditions. Adsorption was highest for tetracycline (Kd, 1093 L/kg), while that for sulfamethazine was negligible (Kd, 1.365 L/kg). All five antibiotics were susceptible to microbial degradation under aerobic conditions, with half-lives ranging from 2.9 to 43.3 d in non-sterilized soil and 40.8 to 86.6 d in sterilized soil. Degradation occurred at a higher rate under aerobic conditions but was relatively persistent under anaerobic conditions. For all the antibiotics, a higher initial concentration was found to slow down degradation and prolong persistence in soil. The degradation behavior of the antibiotics varied in relation to their physicochemical properties as well as the microbial activities and aeration of the recipient soil. The poor adsorption and relative persistence of sulfamethazine under both aerobic and anaerobic conditions suggest that it may pose a higher risk to groundwater quality. An equation was proposed to predict the fate of antibiotics in soil under different field conditions, and assess their risks to the environment.

  6. Adsorption and degradation of five selected antibiotics in agricultural soil.

    PubMed

    Pan, Min; Chu, L M

    2016-03-01

    Large quantities of antibiotics are being added to agricultural fields worldwide through the application of wastewater, manures and biosolids, resulting in antibiotic contamination and elevated environmental risks in terrestrial environments. Most studies on the environmental fate of antibiotics focus on aquatic environments or wastewater treatment plants. Little is known about the behavior of antibiotics at environmentally relevant concentrations in agricultural soil. In this study we evaluated the adsorption and degradation of five different antibiotics (tetracycline, sulfamethazine, norfloxacin, erythromycin, and chloramphenicol) in sterilized and non-sterilized agricultural soils under aerobic and anaerobic conditions. Adsorption was highest for tetracycline (Kd, 1093 L/kg), while that for sulfamethazine was negligible (Kd, 1.365 L/kg). All five antibiotics were susceptible to microbial degradation under aerobic conditions, with half-lives ranging from 2.9 to 43.3 d in non-sterilized soil and 40.8 to 86.6 d in sterilized soil. Degradation occurred at a higher rate under aerobic conditions but was relatively persistent under anaerobic conditions. For all the antibiotics, a higher initial concentration was found to slow down degradation and prolong persistence in soil. The degradation behavior of the antibiotics varied in relation to their physicochemical properties as well as the microbial activities and aeration of the recipient soil. The poor adsorption and relative persistence of sulfamethazine under both aerobic and anaerobic conditions suggest that it may pose a higher risk to groundwater quality. An equation was proposed to predict the fate of antibiotics in soil under different field conditions, and assess their risks to the environment. PMID:26745292

  7. NON-DESTRUCTIVE SOIL CARBON ANALYZER.

    SciTech Connect

    Wielopolski, Lucian; Hendrey, G.; Orion, I.; Prior, S.; Rogers, H.; Runion, B.; Torbert, A.

    2004-02-01

    This report describes the feasibility, calibration, and safety considerations of a non-destructive, in situ, quantitative, volumetric soil carbon analytical method based on inelastic neutron scattering (INS). The method can quantify values as low as 0.018 gC/cc, or about 1.2% carbon by weight with high precision under the instrument's configuration and operating conditions reported here. INS is safe and easy to use, residual soil activation declines to background values in under an hour, and no radiological requirements are needed for transporting the instrument. The labor required to obtain soil-carbon data is about 10-fold less than with other methods, and the instrument offers a nearly instantaneous rate of output of carbon-content values. Furthermore, it has the potential to quantify other elements, particularly nitrogen. New instrumentation was developed in response to a research solicitation from the U.S. Department of Energy (DOE LAB 00-09 Carbon Sequestration Research Program) supporting the Terrestrial Carbon Processes (TCP) program of the Office of Science, Biological and Environmental Research (BER). The solicitation called for developing and demonstrating novel techniques for quantitatively measuring changes in soil carbon. The report includes raw data and analyses of a set of proof-of-concept, double-blind studies to evaluate the INS approach in the first phase of developing the instrument. Managing soils so that they sequester massive amounts of carbon was suggested as a means to mitigate the atmospheric buildup of anthropogenic CO{sub 2}. Quantifying changes in the soils' carbon stocks will be essential to evaluating such schemes and documenting their performance. Current methods for quantifying carbon in soil by excavation and core sampling are invasive, slow, labor-intensive and locally destroy the system being observed. Newly emerging technologies, such as Laser Induced Breakdown Spectroscopy and Near-Infrared Spectroscopy, offer soil-carbon

  8. Agriculture intensifies soil moisture decline in Northern China

    NASA Astrophysics Data System (ADS)

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego G.; Teuling, Adriaan J.; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-07-01

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983-2012, we find that topsoil (0-50 cm) volumetric water content during the growing season has declined significantly (p < 0.01), with a trend of -0.011 to -0.015 m3 m-3 per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system.

  9. Agriculture intensifies soil moisture decline in Northern China.

    PubMed

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego G; Teuling, Adriaan J; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-01-01

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983-2012, we find that topsoil (0-50 cm) volumetric water content during the growing season has declined significantly (p < 0.01), with a trend of -0.011 to -0.015 m(3) m(-3) per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system. PMID:26158774

  10. Agriculture intensifies soil moisture decline in Northern China

    DOE PAGES

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego; Teuling, Adriann; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; et al

    2015-07-09

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983–2012, we find that topsoil (0–50 cm) volumetric water content during the growing season has declined significantly (p<0.01), with a trend of -0.011 to -0.015 m3 m-3 per decade. Observed discharge declines for the three large river basins are consistentmore » with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system.« less

  11. Agriculture intensifies soil moisture decline in Northern China

    SciTech Connect

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego; Teuling, Adriann; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-07-09

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983–2012, we find that topsoil (0–50 cm) volumetric water content during the growing season has declined significantly (p<0.01), with a trend of -0.011 to -0.015 m3 m-3 per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system.

  12. Agriculture intensifies soil moisture decline in Northern China.

    PubMed

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego G; Teuling, Adriaan J; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-07-09

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983-2012, we find that topsoil (0-50 cm) volumetric water content during the growing season has declined significantly (p < 0.01), with a trend of -0.011 to -0.015 m(3) m(-3) per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system.

  13. Agriculture intensifies soil moisture decline in Northern China

    PubMed Central

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego G.; Teuling, Adriaan J.; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-01-01

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983–2012, we find that topsoil (0–50 cm) volumetric water content during the growing season has declined significantly (p < 0.01), with a trend of −0.011 to −0.015 m3 m−3 per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system. PMID:26158774

  14. Behavior of bensulfuron-methyl in an agricultural alkaline soil.

    PubMed

    Delgado-Moreno, L; Sánchez, L; Castillo, A; Pot, V; Peña, A

    2007-01-01

    A field experiment to determine the available bensulfuron-methyl (BSM) in the upper soil layer was conducted in an agricultural area in the South of Spain. To facilitate herbicide analysis, two application rates were employed, 200 g ha(-1) and 5 kg ha(-1). Samples of upper soil and soil solution were collected. Soil solution was sampled by means of metallic samplers, placed at a depth of 35 cm. In the plots receiving the lower dose ceramic suction, porous cups were also installed. Results from soil solution samples showed that the maximum BSM concentration was found after 8-10 days for the high irrigation supply (945 mm) and after 18-25 days for the lower irrigation regime (405 mm). The mathematical model FOCUSPELMO 1.1.1 was applied to interpret the data obtained in the field experiments. In general, there was a reasonable agreement between experimental and simulated data for soil samples, although the model did not acceptably predict herbicide concentrations in water soil samples. Ceramic cups sampled a higher soil water volume and more frequently than did the metallic samplers. However some variable results were attributed to preferential flow. PMID:17454376

  15. Relating results from earthworm toxicity tests to agricultural soil

    USGS Publications Warehouse

    Beyer, W.N.; Greig-Smith, P.W.

    1992-01-01

    The artificial soil tests of the European Economic Community and of the Organization for Economic Cooperation produce data relating earthworm mortality to pesticide concentrations in soil under laboratory conditions. To apply these results to agricultural soils it is necessary to relate these concentrations to amounts of pesticide applied per area. This paper reviews the relevant published literature and suggests a simple relation for regulatory use. Hazards to earthworms from pesticides are suggested to be greatest soon after application, when the pesticides may be concentrated in a soil layer a few millimeters thick. For estimating exposure of earthworms, however, a thicker soil layer should be considered, to account for their movement through soil. During favorable weather conditions, earthworms belonging to species appropriate to the artificial soil test have been reported to confine their activity to a layer about 5 cm. If a 5-cm layer is accepted as relevant for regulatory purposes, then an application of 1 kg/ha would be equivalent to 1-67 ppm (dry) in the artificial soil test.

  16. Effects of soil properties on the transfer of cadmium from soil to wheat in the Yangtze River delta region, China--a typical industry-agriculture transition area.

    PubMed

    Wang, Cheng; Ji, Junfeng; Yang, Zhongfang; Chen, Lingxiao; Browne, Patrick; Yu, Ruilian

    2012-08-01

    In order to identify the effects of soil properties on the transfer of Cd from soil to wheat under actual field conditions, 126 pairs of topsoil and wheat samples were collected from the Yangtze River delta region, China. Relevant parameters (Cd, Ca, Mg, Fe, Mn, Zn, N, P, K, S, pH, total organic carbon, and speciation of soil Cd) in soil and wheat tissues were analyzed, and the results were treated by statistical methods. Soil samples (19.8%) and 14.3% of the wheat grain samples exceeded the relevant maximum permissible Cd concentrations in China for agricultural soil and wheat grain, respectively. The major speciations of Cd in soil were exchangeable, bound to carbonates and fulvic and humic acid fraction, and they were readily affected by soil pH, total Ca, Mg, S and P, DTPA-Fe, Ex-Ca, and Ex-Mg. Cadmium showed a strong correlation with Fe, S, and P present in the grain and the soil, whereas there was no significant correlation in the straw or root. Generally, soil pH, Ca, Mg, Mn, P, and slowly available K restricted Cd transfer from soil to wheat, whereas soil S, N, Zn, DTPA-Fe, and total organic carbon enhance Cd uptake by wheat.

  17. Remote sensing techniques for soil moisture and agricultural drought monitoring

    NASA Astrophysics Data System (ADS)

    Wang, Lingli

    Drought is the most complex and least understood of all natural hazards, affecting more people than any other hazard. Soil moisture is a primary indicator for agricultural drought. This dissertation is aimed at evaluating and investigating soil moisture and drought monitoring using remote sensing techniques. Recent technological advances in remote sensing have shown that soil moisture can be measured by a variety of remote sensing techniques, each with its own strengths and weaknesses. This research is designed to combine the strengths of optical/infrared as well as microwave remote sensing approaches for soil moisture estimation. A soil moisture estimation algorithm at moderate resolution was developed based on the well known 'Universal Triangle' relation by using MODIS land parameters as well as ground measured soil moisture. Though lower in spatial resolution, AMSR-E microwave measurements provides daily global soil moisture of the top soil layer, which are typically less affected by clouds, making them complementary to MODIS measurements over regions of clouds. Considering that the 'Universal Triangle' approach for soil moisture estimation is based on empirical relations which lack solid physical basis, a new physics based drought index, the Normalized Multi-band Drought Index (NMDI) was proposed for monitoring soil and vegetation moisture from space by using one near-infrared (NIR) and two shortwave infrared (SWIR) channels. Typical soil reflectance spectra and satellite acquired canopy reflectances are used to validate the usefulness of NMDI. Its ability for active fire detection has also been investigated using forest fires burning in southern Georgia, USA and southern Greece in 2007. Combining information from multiple NIR and SWIR channels makes NMDI a most promising indicator for drought monitoring and active fire detecting. Given the current technology, satellite remote sensing can only provide soil moisture measurements for the top soil profile, and

  18. Grass mulching effect on infiltration, surface runoff and soil loss of three agricultural soils in Nigeria.

    PubMed

    Adekalu, K O; Olorunfemi, I A; Osunbitan, J A

    2007-03-01

    Mulching the soil surface with a layer of plant residue is an effective method of conserving water and soil because it reduces surface runoff, increases infiltration of water into the soil and retard soil erosion. The effectiveness of using elephant grass (Pennisetum purpureum) as mulching material was evaluated in the laboratory using a rainfall simulator set at rainfall intensities typical of the tropics. Six soil samples, two from each of the three major soil series representing the main agricultural soils in South Western Nigeria were collected, placed on three different slopes, and mulched with different rates of the grass. The surface runoff, soil loss, and apparent cumulative infiltration were then measured under each condition. The results with elephant grass compared favorably with results from previous experiments using rice straw. Runoff and soil loss decreased with the amount of mulch used and increased with slope. Surface runoff, infiltration and soil loss had high correlations (R = 0.90, 0.89, and 0.86, respectively) with slope and mulch cover using surface response analysis. The mean surface runoff was correlated negatively with sand content, while mean soil loss was correlated positively with colloidal content (clay and organic matter) of the soil. Infiltration was increased and soil loss was reduced greatly with the highest cover. Mulching the soils with elephant grass residue may benefit late cropping (second cropping) by increasing stored soil water for use during dry weather and help to reduce erosion on sloping land.

  19. Changes in soil microbial community structure influenced by agricultural management practices in a mediterranean agro-ecosystem.

    PubMed

    García-Orenes, Fuensanta; Morugán-Coronado, Alicia; Zornoza, Raul; Cerdà, Artemi; Scow, Kate

    2013-01-01

    Agricultural practices have proven to be unsuitable in many cases, causing considerable reductions in soil quality. Land management practices can provide solutions to this problem and contribute to get a sustainable agriculture model. The main objective of this work was to assess the effect of different agricultural management practices on soil microbial community structure (evaluated as abundance of phospholipid fatty acids, PLFA). Five different treatments were selected, based on the most common practices used by farmers in the study area (eastern Spain): residual herbicides, tillage, tillage with oats and oats straw mulching; these agricultural practices were evaluated against an abandoned land after farming and an adjacent long term wild forest coverage. The results showed a substantial level of differentiation in the microbial community structure, in terms of management practices, which was highly associated with soil organic matter content. Addition of oats straw led to a microbial community structure closer to wild forest coverage soil, associated with increases in organic carbon, microbial biomass and fungal abundances. The microbial community composition of the abandoned agricultural soil was characterised by increases in both fungal abundances and the metabolic quotient (soil respiration per unit of microbial biomass), suggesting an increase in the stability of organic carbon. The ratio of bacteria:fungi was higher in wild forest coverage and land abandoned systems, as well as in the soil treated with oat straw. The most intensively managed soils showed higher abundances of bacteria and actinobacteria. Thus, the application of organic matter, such as oats straw, appears to be a sustainable management practice that enhances organic carbon, microbial biomass and activity and fungal abundances, thereby changing the microbial community structure to one more similar to those observed in soils under wild forest coverage.

  20. Changes in Soil Microbial Community Structure Influenced by Agricultural Management Practices in a Mediterranean Agro-Ecosystem

    PubMed Central

    García-Orenes, Fuensanta; Morugán-Coronado, Alicia; Zornoza, Raul; Scow, Kate

    2013-01-01

    Agricultural practices have proven to be unsuitable in many cases, causing considerable reductions in soil quality. Land management practices can provide solutions to this problem and contribute to get a sustainable agriculture model. The main objective of this work was to assess the effect of different agricultural management practices on soil microbial community structure (evaluated as abundance of phospholipid fatty acids, PLFA). Five different treatments were selected, based on the most common practices used by farmers in the study area (eastern Spain): residual herbicides, tillage, tillage with oats and oats straw mulching; these agricultural practices were evaluated against an abandoned land after farming and an adjacent long term wild forest coverage. The results showed a substantial level of differentiation in the microbial community structure, in terms of management practices, which was highly associated with soil organic matter content. Addition of oats straw led to a microbial community structure closer to wild forest coverage soil, associated with increases in organic carbon, microbial biomass and fungal abundances. The microbial community composition of the abandoned agricultural soil was characterised by increases in both fungal abundances and the metabolic quotient (soil respiration per unit of microbial biomass), suggesting an increase in the stability of organic carbon. The ratio of bacteria:fungi was higher in wild forest coverage and land abandoned systems, as well as in the soil treated with oat straw. The most intensively managed soils showed higher abundances of bacteria and actinobacteria. Thus, the application of organic matter, such as oats straw, appears to be a sustainable management practice that enhances organic carbon, microbial biomass and activity and fungal abundances, thereby changing the microbial community structure to one more similar to those observed in soils under wild forest coverage. PMID:24260409

  1. Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters

    NASA Astrophysics Data System (ADS)

    Morugán-Coronado, A.; Arcenegui, V.; García-Orenes, F.; Mataix-Solera, J.; Mataix-Beneyto, J.

    2013-03-01

    The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. These indices represent the balance reached among properties in "steady state" soils. This study was carried out in four study sites from SE Spain irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.

  2. Terraced agriculture protects soil from erosion: Case studies in Madagascar

    NASA Astrophysics Data System (ADS)

    Rabesiranana, Naivo; Rasolonirina, Martin; Fanantenansoa Solonjara, Asivelo; Nomenjanahary Ravoson, Heritiana; Mabit, Lionel

    2016-04-01

    - Soil degradation is a major concern in Madagascar but quantitative information is not widely available. Due to its impact on the sustainability of agricultural production, there is a clear need to acquire data on the extent and magnitude of soil erosion/sedimentation under various agricultural practices in order to promote effective conservation strategies. Caesium-137 and 210Pbex fallout radionuclides (FRNs) possess particular characteristics that make them effective soil tracers for erosion studies. After fallout, 137Cs and 210Pbex are rapidly adsorbed onto fine soil particles. But to date, combined use of these FRNs has never been used to document soil erosion in Madagascar. The study area is located 40 km east of Antananarivo, in Madagascar highlands. Two adjacent cultivated fields have been selected (i.e. a sloped field and a terraced field) as well as an undisturbed reference site in the vicinity of these agricultural fields. Soil samples were collected along downslope transects using motorized corer. The 137Cs and 210Pb gamma analysis were performed at the Institut National des Sciences et Techniques Nucléaires (INSTN-Madagascar) using a high resolution and low background N-type HPGe detector. Results showed that at the terraced field, 137Cs and 210Pbex inventories reached 145 Bq/m2 to 280 Bq/m2 and 2141 Bq/m2 to 4253 Bq/m2, respectively. At the sloped field, the 137Cs and 210Pbex inventories values ranged from 110 Bq/m2 to 280 Bq/m2 and from 2026 Bq/m2 to 4110 Bq/m2, respectively. The net soil erosion determined for the sloped field were 9.6 t/ha/y and 7.2 t/ha/y for 137Cs and 210Pbex methods, respectively. In contrast, at the terraced field, the net soil erosion rates reached only 3.4 t/ha/y and 3.8 t/ha/y, respectively. The preliminary results of this research highlighted that terraced agricultural practice provides an efficient solution to protect soil resources of the Malagasy highlands.

  3. Ice Nucleation Activity of Various Agricultural Soil Dust Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Schiebel, Thea; Höhler, Kristina; Funk, Roger; Hill, Thomas C. J.; Levin, Ezra J. T.; Nadolny, Jens; Steinke, Isabelle; Suski, Kaitlyn J.; Ullrich, Romy; Wagner, Robert; Weber, Ines; DeMott, Paul J.; Möhler, Ottmar

    2016-04-01

    Recent investigations at the cloud simulation chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) suggest that agricultural soil dust has an ice nucleation ability that is enhanced up to a factor of 10 compared to desert dust, especially at temperatures above -26 °C (Steinke et al., in preparation for submission). This enhancement might be caused by the contribution of very ice-active biological particles. In addition, soil dust aerosol particles often contain a considerably higher amount of organic matter compared to desert dust particles. To test agricultural soil dust as a source of ice nucleating particles, especially for ice formation in warm clouds, we conducted a series of laboratory measurements with different soil dust samples to extend the existing AIDA dataset. The AIDA has a volume of 84 m3 and operates under atmospherically relevant conditions over wide ranges of temperature, pressure and humidity. By controlled adiabatic expansions, the ascent of an air parcel in the troposphere can be simulated. As a supplement to the AIDA facility, we use the INKA (Ice Nucleation Instrument of the KArlsruhe Institute of Technology) continuous flow diffusion chamber based on the design by Rogers (1988) to expose the sampled aerosol particles to a continuously increasing saturation ratio by keeping the aerosol temperature constant. For our experiments, soil dust was dry dispersed into the AIDA vessel. First, fast saturation ratio scans at different temperatures were performed with INKA, sampling soil dust aerosol particles directly from the AIDA vessel. Then, we conducted the AIDA expansion experiment starting at a preset temperature. The combination of these two different methods provides a robust data set on the temperature-dependent ice activity of various agriculture soil dust aerosol particles with a special focus on relatively high temperatures. In addition, to extend the data set, we investigated the role of biological and organic matter in more

  4. Soil carbon sequestration: Quantifying this ecosystem service

    EPA Science Inventory

    Soils have a crucial role in supplying many goods and services that society depends upon on a daily basis. These include food and fiber production, water cleansing and supply, nutrient cycling, waste isolation and degradation. Soils also provide a significant amount of carbon s...

  5. Agricultural plants and soil as a reservoir for Pseudomonas aeruginosa.

    PubMed

    Green, S K; Schroth, M N; Cho, J J; Kominos, S K; Vitanza-jack, V B

    1974-12-01

    Pseudomonas aeruginosa was detected in 24% of the soil samples but in only 0.13% of the vegetable samples from various agricultural areas of California. The distribution of pyocin types of soil and vegetable isolates was similar to that of clinical strains, and three of the soil isolates were resistant to carbenicillin. Pseudomonas aeruginosa multiplied in lettuce and bean under conditions of high temperature and high relative humidity (27 C and 80-95% relative humidity) but declined when the temperature and humidity were lowered (16 C, 55-75% relative humidity). The results suggest that soil is a reservior for P. aeruginosa and that the bacterium has the capacity to colonize plants during favorable conditions of temperature and moisture. PMID:4217591

  6. Genotoxicity of agricultural soils in the vicinity of industrial area.

    PubMed

    Ansari, Mohd Ikram; Malik, Abdul

    2009-03-17

    Soil samples from agricultural fields (cultivated) in the vicinity of industrial area of Ghaziabad City (India) were collected. In this city, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the food crops. This practice has been polluting the soil and pollutants might reach the food chain. Gas chromatographic analysis show the presence of certain organochlorine (DDE, DDT, dieldrin, aldrin and endosulfan) and organophosphorus (dimethoate, malathion, methylparathion and chlorpyrifos) pesticides in soil samples. Samples were extracted using different solvents, i.e. methanol, chloroform, acetonitrile, hexane and acetone (all were HPLC-grade, SRL, India), and the extracts were assayed for genotoxic potential using Ames Salmonella/microsome test, DNA repair defective mutants and bacteriophage lambda systems. TA98 and TA100 were found to be the most sensitive strains to all the soil extracts tested. Methanol extracts exhibited a maximum mutagenicity with TA98 strain {540 (-S9) and 638 (+S9) revertants/g of soil} and 938 (-S9) and 1008 (+S9) revertants/g of soil with TA100 strain. The damage in the DNA repair defective mutants was found maximum with methanolic extract followed by acetonitrile, chloroform, hexane and acetone at the dose level of 40 microl/ml culture after 6h of treatment. The survival was 25, 30, 32, 33 and 35% in polA strain after 6h of treatment when tested with wastewater irrigated soil extracts of methanol, acetonitrile, chloroform, hexane and acetone, respectively. A significant decrease in the plaque forming units of bacteriophage lambda was also observed when treated with 40 microl of test samples. Present results showed that methanolic extracts of soil were more toxic than other soil extracts. The soil is accumulating a large number of pollutants due to wastewater irrigation and this practice of accumulation has an impact on soil health.

  7. Environmental Controls of Soil Organic Carbon in Soils Across Amazonia

    NASA Astrophysics Data System (ADS)

    Quesada, Carlos Alberto; Paz, Claudia; Phillips, Oliver; Nonato Araujo Filho, Raimundo; Lloyd, Jon

    2015-04-01

    Amazonian forests store and cycle a significant amount of carbon on its soils and vegetation. Yet, Amazonian forests are now subject to strong environmental pressure from both land use and climate change. Some of the more dramatic model projections for the future of the Amazon predict a major change in precipitation followed by savanization of most currently forested areas, resulting in major carbon losses to the atmosphere. However, how soil carbon stocks will respond to climatic and land use changes depend largely on how soil carbon is stabilized. Amazonian soils are highly diverse, being very variable in their weathering levels and chemical and physical properties, and thus it is important to consider how the different soils of the Basin stabilize and store soil organic carbon (SOC). The wide variation in soil weathering levels present in Amazonia, suggests that soil groups with contrasting pedogenetic development should differ in their predominant mechanism of SOC stabilization. In this study we investigated the edaphic, mineralogical and climatic controls of SOC concentration in 147 pristine forest soils across nine different countries in Amazonia, encompassing 14 different WRB soil groups. Soil samples were collected in 1 ha permanent plots used for forest dynamics studies as part of the RAINFOR project. Only 0-30 cm deep averages are reported here. Soil samples were analyzed for carbon and nitrogen and for their chemical (exchangeable bases, phosphorus, pH) and physical properties, (particle size, bulk density) and mineralogy through standard selective dissolution techniques (Fe and Al oxides) and by semi-quantitative X-Ray diffraction. In Addition, selected soils from each soil group had SOC fractionated by physical and chemical techniques. Our results indicate that different stabilization mechanisms are responsible for SOC stabilization in Amazonian soils with contrasting pedogenetic level. Ferralsols and Acrisols were found to have uniform mineralogy

  8. Organochlorine insecticide residues in soils and soil invertebrates from agricultural lands

    USGS Publications Warehouse

    Gish, C.D.

    1970-01-01

    Soils and earthworms and other soil invertebrates were collected from 67 agricultural fields in eight States. Samples were analyzed by gas chromatography for DDE, DDD, DDT, aldrin, dieldrin, endrin, heptachlor, heptachlor epoxide, and gamma-chlordane insecticides. Organochlorine insecticides in soils averaged 1.5 ppm, dry weight, and in earthworms, 13.8 ppm. Residues in earthworms averaged nine times that in soils. Residues ranged from a trace to 19.1 ppm in soils and from a trace to 159.4 ppm in earthworms. Residues in beetle larvae from two fields averaged 0.6 ppm; in snails from two fields, 3.5 ppm; and in slugs from four fields, 89.0 ppm. Amounts of insecticides in earthworms varied directly with amounts in soils. Coefficients of correlation between residues in soils and residues in earthworms usually were significant for DDE, DDD, and DDT regardless of crop or soil type.

  9. Soil Organic Matter Stability and Soil Carbon Storage with Changes in Land Use Intensity in Uganda

    NASA Astrophysics Data System (ADS)

    Tiemann, L. K.; Grandy, S.; Hartter, J.

    2014-12-01

    As the foundation of soil fertility, soil organic matter (SOM) formation and break-down is a critical factor of agroecosystem sustainability. In tropical systems where soils are quickly weathered, the link between SOM and soil fertility is particularly strong; however, the mechanisms controlling the stabilization and destabilization of SOM are not well characterized in tropical soils. In western Uganda, we collected soil samples under different levels of land use intensity including maize fields, banana plantations and inside an un-cultivated native tropical forest, Kibale National Park (KNP). To better understand the link between land use intensity and SOM stability we measured total soil C and N, and respiration rates during a 369 d soil incubation. In addition, we separated soils into particle size fractions, and mineral adsorbed SOM in the silt (2-50 μm ) and clay (< 2 μm) fractions was dissociated, purified and chemically characterized via pyrolysis-GC/MS. Cultivated soil C and N have declined by 22 and 48%, respectively, in comparison to uncultivated KNP soils. Incubation data indicate that over the last decade, relatively accessible and labile soil organic carbon (SOC) pools have been depleted by 55-59% in cultivated soils. As a result of this depletion, the chemical composition of SOM has been altered such that clay and silt associated SOM differed significantly between agricultural fields and KNP. In particular, nitrogen containing compounds were in lower abundance in agricultural compared to KNP soils. This suggests that N depletion due to agriculture has advanced to pools of mineral associated organic N that are typically protected from break-down. In areas where land use intensity is relatively greater, increases in polysaccharides and lipids in maize fields compared to KNP indicate increases in microbial residues and decomposition by-products as microbes mine SOM for organic N. Chemical characterization of post-incubation SOM will help us better

  10. Black Carbon Contribution to Organic Carbon Stocks in Urban Soil.

    PubMed

    Edmondson, Jill L; Stott, Iain; Potter, Jonathan; Lopez-Capel, Elisa; Manning, David A C; Gaston, Kevin J; Leake, Jonathan R

    2015-07-21

    Soil holds 75% of the total organic carbon (TOC) stock in terrestrial ecosystems. This comprises ecosystem-derived organic carbon (OC) and black carbon (BC), a recalcitrant product of the incomplete combustion of fossil fuels and biomass. Urban topsoils are often enriched in BC from historical emissions of soot and have high TOC concentrations, but the contribution of BC to TOC throughout the urban soil profile, at a regional scale is unknown. We sampled 55 urban soil profiles across the North East of England, a region with a history of coal burning and heavy industry. Through combined elemental and thermogravimetic analyses, we found very large total soil OC stocks (31-65 kg m(-2) to 1 m), exceeding typical values reported for UK woodland soils. BC contributed 28-39% of the TOC stocks, up to 23 kg C m(-2) to 1 m, and was affected by soil texture. The proportional contribution of the BC-rich fraction to TOC increased with soil depth, and was enriched in topsoil under trees when compared to grassland. Our findings establish the importance of urban ecosystems in storing large amounts of OC in soils and that these soils also capture a large proportion of BC particulates emitted within urban areas.

  11. GEMAS: Unmixing magnetic properties of European agricultural soil

    NASA Astrophysics Data System (ADS)

    Fabian, Karl; Reimann, Clemens; Kuzina, Dilyara; Kosareva, Lina; Fattakhova, Leysan; Nurgaliev, Danis

    2016-04-01

    High resolution magnetic measurements provide new methods for world-wide characterization and monitoring of agricultural soil which is essential for quantifying geologic and human impact on the critical zone environment and consequences of climatic change, for planning economic and ecological land use, and for forensic applications. Hysteresis measurements of all Ap samples from the GEMAS survey yield a comprehensive overview of mineral magnetic properties in European agricultural soil on a continental scale. Low (460 Hz), and high frequency (4600 Hz) magnetic susceptibility k were measured using a Bartington MS2B sensor. Hysteresis properties were determined by a J-coercivity spectrometer, built at the paleomagnetic laboratory of Kazan University, providing for each sample a modified hysteresis loop, backfield curve, acquisition curve of isothermal remanent magnetization, and a viscous IRM decay spectrum. Each measurement set is obtained in a single run from zero field up to 1.5 T and back to -1.5 T. The resulting data are used to create the first continental-scale maps of magnetic soil parameters. Because the GEMAS geochemical atlas contains a comprehensive set of geochemical data for the same soil samples, the new data can be used to map magnetic parameters in relation to chemical and geological parameters. The data set also provides a unique opportunity to analyze the magnetic mineral fraction of the soil samples by unmixing their IRM acquisition curves. The endmember coefficients are interpreted by linear inversion for other magnetic, physical and chemical properties which results in an unprecedented and detailed view of the mineral magnetic composition of European agricultural soils.

  12. Combining Soil Databases for Topsoil Organic Carbon Mapping in Europe.

    PubMed

    Aksoy, Ece; Yigini, Yusuf; Montanarella, Luca

    2016-01-01

    Accuracy in assessing the distribution of soil organic carbon (SOC) is an important issue because of playing key roles in the functions of both natural ecosystems and agricultural systems. There are several studies in the literature with the aim of finding the best method to assess and map the distribution of SOC content for Europe. Therefore this study aims searching for another aspect of this issue by looking to the performances of using aggregated soil samples coming from different studies and land-uses. The total number of the soil samples in this study was 23,835 and they're collected from the "Land Use/Cover Area frame Statistical Survey" (LUCAS) Project (samples from agricultural soil), BioSoil Project (samples from forest soil), and "Soil Transformations in European Catchments" (SoilTrEC) Project (samples from local soil data coming from six different critical zone observatories (CZOs) in Europe). Moreover, 15 spatial indicators (slope, aspect, elevation, compound topographic index (CTI), CORINE land-cover classification, parent material, texture, world reference base (WRB) soil classification, geological formations, annual average temperature, min-max temperature, total precipitation and average precipitation (for years 1960-1990 and 2000-2010)) were used as auxiliary variables in this prediction. One of the most popular geostatistical techniques, Regression-Kriging (RK), was applied to build the model and assess the distribution of SOC. This study showed that, even though RK method was appropriate for successful SOC mapping, using combined databases was not helpful to increase the statistical significance of the method results for assessing the SOC distribution. According to our results; SOC variation was mainly affected by elevation, slope, CTI, average temperature, average and total precipitation, texture, WRB and CORINE variables for Europe scale in our model. Moreover, the highest average SOC contents were found in the wetland areas; agricultural

  13. Combining Soil Databases for Topsoil Organic Carbon Mapping in Europe.

    PubMed

    Aksoy, Ece; Yigini, Yusuf; Montanarella, Luca

    2016-01-01

    Accuracy in assessing the distribution of soil organic carbon (SOC) is an important issue because of playing key roles in the functions of both natural ecosystems and agricultural systems. There are several studies in the literature with the aim of finding the best method to assess and map the distribution of SOC content for Europe. Therefore this study aims searching for another aspect of this issue by looking to the performances of using aggregated soil samples coming from different studies and land-uses. The total number of the soil samples in this study was 23,835 and they're collected from the "Land Use/Cover Area frame Statistical Survey" (LUCAS) Project (samples from agricultural soil), BioSoil Project (samples from forest soil), and "Soil Transformations in European Catchments" (SoilTrEC) Project (samples from local soil data coming from six different critical zone observatories (CZOs) in Europe). Moreover, 15 spatial indicators (slope, aspect, elevation, compound topographic index (CTI), CORINE land-cover classification, parent material, texture, world reference base (WRB) soil classification, geological formations, annual average temperature, min-max temperature, total precipitation and average precipitation (for years 1960-1990 and 2000-2010)) were used as auxiliary variables in this prediction. One of the most popular geostatistical techniques, Regression-Kriging (RK), was applied to build the model and assess the distribution of SOC. This study showed that, even though RK method was appropriate for successful SOC mapping, using combined databases was not helpful to increase the statistical significance of the method results for assessing the SOC distribution. According to our results; SOC variation was mainly affected by elevation, slope, CTI, average temperature, average and total precipitation, texture, WRB and CORINE variables for Europe scale in our model. Moreover, the highest average SOC contents were found in the wetland areas; agricultural

  14. Combining Soil Databases for Topsoil Organic Carbon Mapping in Europe

    PubMed Central

    Aksoy, Ece

    2016-01-01

    Accuracy in assessing the distribution of soil organic carbon (SOC) is an important issue because of playing key roles in the functions of both natural ecosystems and agricultural systems. There are several studies in the literature with the aim of finding the best method to assess and map the distribution of SOC content for Europe. Therefore this study aims searching for another aspect of this issue by looking to the performances of using aggregated soil samples coming from different studies and land-uses. The total number of the soil samples in this study was 23,835 and they’re collected from the “Land Use/Cover Area frame Statistical Survey” (LUCAS) Project (samples from agricultural soil), BioSoil Project (samples from forest soil), and “Soil Transformations in European Catchments” (SoilTrEC) Project (samples from local soil data coming from six different critical zone observatories (CZOs) in Europe). Moreover, 15 spatial indicators (slope, aspect, elevation, compound topographic index (CTI), CORINE land-cover classification, parent material, texture, world reference base (WRB) soil classification, geological formations, annual average temperature, min-max temperature, total precipitation and average precipitation (for years 1960–1990 and 2000–2010)) were used as auxiliary variables in this prediction. One of the most popular geostatistical techniques, Regression-Kriging (RK), was applied to build the model and assess the distribution of SOC. This study showed that, even though RK method was appropriate for successful SOC mapping, using combined databases was not helpful to increase the statistical significance of the method results for assessing the SOC distribution. According to our results; SOC variation was mainly affected by elevation, slope, CTI, average temperature, average and total precipitation, texture, WRB and CORINE variables for Europe scale in our model. Moreover, the highest average SOC contents were found in the wetland areas

  15. Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters

    NASA Astrophysics Data System (ADS)

    Morugán-Coronado, A.; Arcenegui, V.; García-Orenes, F.; Mataix-Solera, J.; Mataix-Beneyto, J.

    2012-12-01

    The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships, the equilibrium reached and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. This study was carried out in three areas of Alicante Province (SE Spain) irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.

  16. Soil strength and macropore volume limit root elongation rates in many UK agricultural soils

    PubMed Central

    Valentine, Tracy A.; Hallett, Paul D.; Binnie, Kirsty; Young, Mark W.; Squire, Geoffrey R.; Hawes, Cathy; Bengough, A. Glyn

    2012-01-01

    Background and Aims Simple indicators of crop and cultivar performance across a range of soil types and management are needed for designing and testing sustainable cropping practices. This paper determined the extent to which soil chemical and physical properties, particularly soil strength and pore-size distribution influences root elongation in a wide range of agricultural top soils, using a seedling-based indicator. Methods Intact soil cores were sampled from the topsoil of 59 agricultural fields in Scotland, representing a wide geographic spread, range of textures and management practices. Water release characteristics, dry bulk density and needle penetrometer resistance were measured on three cores from each field. Soil samples from the same locations were sieved, analysed for chemical characteristics, and packed to dry bulk density of 1·0 g cm−3 to minimize physical constraints. Root elongation rates were determined for barley seedlings planted in both intact field and packed soil cores at a water content close to field capacity (–20 kPa matric potential). Key Results Root elongation in field soil was typically less than half of that in packed soils. Penetrometer resistance was typically between 1 and 3 MPa for field soils, indicating the soils were relatively hard, despite their moderately wet condition (compared with <0·2 MPa for packed soil). Root elongation was strongly linked to differences in physical rather than chemical properties. In field soil root elongation was related most closely to the volume of soil pores between 60 µm and 300 µm equivalent diameter, as estimated from water-release characteristics, accounting for 65·7 % of the variation in the elongation rates. Conclusions Root elongation rate in the majority of field soils was slower than half of the unimpeded (packed) rate. Such major reductions in root elongation rates will decrease rooting volumes and limit crop growth in soils where nutrients and water are scarce. PMID:22684682

  17. Fate of the antifungal drug clotrimazole in agricultural soil.

    PubMed

    Sabourin, Lyne; Al-Rajab, Abdul Jabbar; Chapman, Ralph; Lapen, David R; Topp, Edward

    2011-03-01

    Clotrimazole is a broad-spectrum antimycotic drug used for the treatment of dermatological and gynecological infections; it is incompletely broken down during sewage treatment and could potentially reach agricultural land through the application of municipal biosolids or wastewater. In the absence of any environmental fate data, we evaluated the persistence and dissipation pathways of (3)H-clotrimazole during laboratory incubations of agricultural soils. Clotrimazole was removed from a loam (time to dissipate 50% = 68 d), a sandy loam (time to dissipate 50% = 36 d), and a clay loam (time to dissipate 50% = 55 d), with formation of nonextractable residues being the major sink for (3) H. Their parent compound had no significant mineralization, as evidenced by the lack of formation of (3) H(2) O. Up to 15% of the applied radioactivity was recovered in the form of [(3)H]-(2-chlorophenyl)diphenyl methanol. The rate of clotrimazole dissipation in the loam soil did not vary with moisture content, but it was slower at a lower temperature (number of days to dissipate 50% = 275.6 d at 4°C). Addition of municipal biosolids to the loam soil did not vary the clotrimazole dissipation rate. In summary, the present study has established that clotrimazole is dissipated in soil, at rates that varied with soil texture and temperature. Clotrimazole dissipation was accompanied by the formation of nonextractable residues and detectable extractable residues of the transformation product (2-chlorophenyl)diphenyl methanol. PMID:21298703

  18. Climate, soil texture, and soil types affect the contributions of fine-fraction-stabilized carbon to total soil organic carbon in different land uses across China.

    PubMed

    Cai, Andong; Feng, Wenting; Zhang, Wenju; Xu, Minggang

    2016-05-01

    Mineral-associated organic carbon (MOC), that is stabilized by fine soil particles (i.e., silt plus clay, <53 μm), is important for soil organic carbon (SOC) persistence and sequestration, due to its large contribution to total SOC (TSOC) and long turnover time. Our objectives were to investigate how climate, soil type, soil texture, and agricultural managements affect MOC contributions to TSOC in China. We created a dataset from 103 published papers, including 1106 data points pairing MOC and TSOC across three major land use types: cropland, grassland, and forest. Overall, the MOC/TSOC ratio ranged from 0.27 to 0.80 and varied significantly among soil groups in cropland, grassland, and forest. Croplands and forest exhibited significantly higher median MOC/TSOC ratios than in grassland. Moreover, forest and grassland soils in temperate regions had higher MOC/TSOC ratios than in subtropical regions. Furthermore, the MOC/TSOC ratio was much higher in ultisol, compared with the other soil types. Both the MOC content and MOC/TSOC ratio were positively correlated with the amount of fine fraction (silt plus clay) in soil, highlighting the importance of soil texture in stabilizing organic carbon across various climate zones. In cropland, different fertilization practices and land uses (e.g., upland, paddy, and upland-paddy rotation) significantly altered MOC/TSOC ratios, but not in cropping systems (e.g., mono- and double-cropping) characterized by climatic differences. This study demonstrates that the MOC/TSOC ratio is mainly driven by soil texture, soil types, and related climate and land uses, and thus the variations in MOC/TSOC ratios should be taken into account when quantitatively estimating soil C sequestration potential of silt plus clay particles on a large scale. PMID:26905446

  19. Climate, soil texture, and soil types affect the contributions of fine-fraction-stabilized carbon to total soil organic carbon in different land uses across China.

    PubMed

    Cai, Andong; Feng, Wenting; Zhang, Wenju; Xu, Minggang

    2016-05-01

    Mineral-associated organic carbon (MOC), that is stabilized by fine soil particles (i.e., silt plus clay, <53 μm), is important for soil organic carbon (SOC) persistence and sequestration, due to its large contribution to total SOC (TSOC) and long turnover time. Our objectives were to investigate how climate, soil type, soil texture, and agricultural managements affect MOC contributions to TSOC in China. We created a dataset from 103 published papers, including 1106 data points pairing MOC and TSOC across three major land use types: cropland, grassland, and forest. Overall, the MOC/TSOC ratio ranged from 0.27 to 0.80 and varied significantly among soil groups in cropland, grassland, and forest. Croplands and forest exhibited significantly higher median MOC/TSOC ratios than in grassland. Moreover, forest and grassland soils in temperate regions had higher MOC/TSOC ratios than in subtropical regions. Furthermore, the MOC/TSOC ratio was much higher in ultisol, compared with the other soil types. Both the MOC content and MOC/TSOC ratio were positively correlated with the amount of fine fraction (silt plus clay) in soil, highlighting the importance of soil texture in stabilizing organic carbon across various climate zones. In cropland, different fertilization practices and land uses (e.g., upland, paddy, and upland-paddy rotation) significantly altered MOC/TSOC ratios, but not in cropping systems (e.g., mono- and double-cropping) characterized by climatic differences. This study demonstrates that the MOC/TSOC ratio is mainly driven by soil texture, soil types, and related climate and land uses, and thus the variations in MOC/TSOC ratios should be taken into account when quantitatively estimating soil C sequestration potential of silt plus clay particles on a large scale.

  20. Long-term nickel exposure altered the bacterial community composition but not diversity in two contrasting agricultural soils.

    PubMed

    Li, Jing; Hu, Hang-Wei; Ma, Yi-Bing; Wang, Jun-Tao; Liu, Yu-Rong; He, Ji-Zheng

    2015-07-01

    Nickel pollution imposes deleterious effects on soil ecosystem. The responses of soil microorganisms to long-term nickel pollution under field conditions remain largely unknown. Here, we used high-throughput sequencing to elucidate the impacts of long-term nickel pollution on soil bacterial communities in two contrasting agricultural soils. Our results found that the soil microbial biomass carbon consistently decreased along the nickel gradients in both soils. Nickel pollution selectively favored or impeded the prevalence of several dominant bacterial guilds, in particular, Actinobacteria showed tolerance, while Acidobacteria and Planctomycetes displayed sensitivity. Despite the apparent shifts in the bacterial community composition, no clear tendency in the bacterial diversity and abundance was identified along the nickel gradients in either soil. Collectively, we provide evidence that long-term nickel pollution shifted the soil bacterial communities, resulting in the decrease of microbial biomass although the bacterial diversity was not significantly changed.

  1. Optimizing carbon storage and biodiversity protection in tropical agricultural landscapes.

    PubMed

    Gilroy, James J; Woodcock, Paul; Edwards, Felicity A; Wheeler, Charlotte; Medina Uribe, Claudia A; Haugaasen, Torbjørn; Edwards, David P

    2014-07-01

    With the rapidly expanding ecological footprint of agriculture, the design of farmed landscapes will play an increasingly important role for both carbon storage and biodiversity protection. Carbon and biodiversity can be enhanced by integrating natural habitats into agricultural lands, but a key question is whether benefits are maximized by including many small features throughout the landscape ('land-sharing' agriculture) or a few large contiguous blocks alongside intensive farmland ('land-sparing' agriculture). In this study, we are the first to integrate carbon storage alongside multi-taxa biodiversity assessments to compare land-sparing and land-sharing frameworks. We do so by sampling carbon stocks and biodiversity (birds and dung beetles) in landscapes containing agriculture and forest within the Colombian Chocó-Andes, a zone of high global conservation priority. We show that woodland fragments embedded within a matrix of cattle pasture hold less carbon per unit area than contiguous primary or advanced secondary forests (>15 years). Farmland sites also support less diverse bird and dung beetle communities than contiguous forests, even when farmland retains high levels of woodland habitat cover. Landscape simulations based on these data suggest that land-sparing strategies would be more beneficial for both carbon storage and biodiversity than land-sharing strategies across a range of production levels. Biodiversity benefits of land-sparing are predicted to be similar whether spared lands protect primary or advanced secondary forests, owing to the close similarity of bird and dung beetle communities between the two forest classes. Land-sparing schemes that encourage the protection and regeneration of natural forest blocks thus provide a synergy between carbon and biodiversity conservation, and represent a promising strategy for reducing the negative impacts of agriculture on tropical ecosystems. However, further studies examining a wider range of ecosystem

  2. Changes in soil fungal communities across a landscape of agricultural soil land-uses

    NASA Astrophysics Data System (ADS)

    Berthrong, S. T.; Buckley, D. H.; Drinkwater, L. E.

    2012-12-01

    Agricultural management is a major driver of changes in soils and their resident microbial communities, but we do not yet have a clear picture of how agriculture affects soil fungi. This is an important gap in our knowledge since fungi play an important role in many soil processes. Previous research has suggested that organic management practices can lead to an increase in soil fungal community diversity, which could have impacts on soil processes and alter the long term trajectory of soil quality in agricultural systems. Also, the relationship between management effects, biogeography, and soil fungi is not clear. The biogeography of macroscopic species is well described by taxa-area relationships and distance decay models, and recent research has suggested that certain subsets of fungi (e.g. AMF, litter sapotrophs) demonstrate similar patterns. However there is little information on how soil fungi as a whole are distributed across a landscape with soils under different managements. The goal of this project was to examine how different management practices alter soil fungal communities across a landscape of agricultural fields in upstate NY. We asked several specific questions: 1) Do different types of agricultural land-uses lead to divergent or convergent communities of soil fungi? 2) If soil type is held constant, do soil fungal communities diverge with geographic distance? 3) What are the major fungal groups that change in response to soil management, and are they cosmopolitan or endemic across the landscape? We studied these questions across agricultural fields in upstate NY that ranged from conventional corn, organic grains/corn, and long-term pasture. We sampled four fields (conventional, 10 and 20 year organic, and pasture) that had identical soils types and ranged from 100 m to 4 km apart. We utilized a multiplexed pyrosequencing approach on genomic DNA to analyze the structure of the soils' fungal communities. This approach allowed us to study soil fungi

  3. Hyperspectral mapping of crop and soils for precision agriculture

    NASA Astrophysics Data System (ADS)

    Whiting, Michael L.; Ustin, Susan L.; Zarco-Tejada, Pablo; Palacios-Orueta, Alicia; Vanderbilt, Vern C.

    2006-08-01

    Precision agriculture requires high spectral and spatial resolution imagery for advanced analyses of crop and soil conditions to increase environmental protection and producers' sustainability. GIS models that anticipate crop responses to nutrients, water, and pesticides require high spatial detail to generate application prescription maps. While the added precision of geo-spatial interpolation to field scouting generates improved zone maps and are an improvement over field-wide applications, it is limited in detail due to expense, and lacks the high precision required for pixel level applications. Multi-spectral imagery gives the spatial detail required, but broad band indexes are not sensitive to many variables in the crop and soil environment. Hyperspectral imagery provides both the spatial detail of airborne imagery and spectral resolution for spectroscopic and narrow band analysis techniques developed over recent decades in the laboratory that will advance precise determination of water and bio-physical properties of crops and soils. For several years, we have conducted remote sensing investigations to improve cotton production through field spectrometer measurements, and plant and soil samples in commercial fields and crop trials. We have developed spectral analyses techniques for plant and soil conditions through determination of crop water status, effectiveness of pre-harvest defoliant applications, and soil characterizations. We present the most promising of these spectroscopic absorption and narrow band index techniques, and their application to airborne hyperspectral imagery in mapping the variability in crops and soils.

  4. Knowledge needs, available practices, and future challenges in agricultural soils

    NASA Astrophysics Data System (ADS)

    Key, Georgina; Whitfield, Mike G.; Cooper, Julia; De Vries, Franciska T.; Collison, Martin; Dedousis, Thanasis; Heathcote, Richard; Roth, Brendan; Mohammed, Shamal; Molyneux, Andrew; Van der Putten, Wim H.; Dicks, Lynn V.; Sutherland, William J.; Bardgett, Richard D.

    2016-10-01

    The goal of this study is to clarify research needs and identify effective practices for enhancing soil health. This was done by a synopsis of soil literature that specifically tests practices designed to maintain or enhance elements of soil health. Using an expert panel of soil scientists and practitioners, we then assessed the evidence in the soil synopsis to highlight practices beneficial to soil health, practices considered detrimental, and practices that need further investigation. A partial Spearman's correlation was used to analyse the panel's responses. We found that increased certainty in scientific evidence led to practices being considered to be more effective due to them being empirically justified. This suggests that for practices to be considered effective and put into practice, a substantial body of research is needed to support the effectiveness of the practice. This is further supported by the high proportion of practices (33 %), such as changing the timing of ploughing or amending the soil with crops grown as green manures, that experts felt had unknown effectiveness, usually due to insufficiently robust evidence. Only 7 of the 27 reviewed practices were considered to be beneficial, or likely to be beneficial in enhancing soil health. These included the use of (1) integrated nutrient management (organic and inorganic amendments); (2) cover crops; (3) crop rotations; (4) intercropping between crop rows or underneath the main crop; (5) formulated chemical compounds (such as nitrification inhibitors); (6) control of traffic and traffic timing; and (7) reducing grazing intensity. Our assessment, which uses the Delphi technique, is increasingly used to improve decision-making in conservation and agricultural policy, identified practices that can be put into practice to benefit soil health. Moreover, it has enabled us to identify practices that need further research and a need for increased communication between researchers, policy-makers, and

  5. Fates of eroded soil organic carbon: Mississippi Basin case study

    USGS Publications Warehouse

    Smith, S.V.; Sleezer, R.O.; Renwick, W.H.; Buddemeier, R.W.

    2005-01-01

    We have developed a mass balance analysis of organic carbon (OC) across the five major river subsystems of the Mississippi (MS) Basin (an area of 3.2 ?? 106 km2). This largely agricultural landscape undergoes a bulk soil erosion rate of ???480 t??km -2??yr-1 (???1500 ?? 106 t/yr, across the MS Basin), and a soil organic carbon (SOC) erosion rate of ???7 t??km-2??yr-1 (???22 ?? 106 t/yr). Erosion translocates upland SOC to alluvial deposits, water impoundments, and the ocean. Soil erosion is generally considered to be a net source of CO2 release to the atmosphere in global budgets. However, our results indicate that SOC erosion and relocation of soil apparently can reduce the net SOC oxidation rate of the original upland SOC while promoting net replacement of eroded SOC in upland soils that were eroded. Soil erosion at the MS Basin scale is, therefore, a net CO2 sink rather than a source. ?? 2005 by the Ecological Society of America.

  6. Assessing the use of treated waste water for irrigation agricultural lands by using soil quality indices

    NASA Astrophysics Data System (ADS)

    Arcenegui, V.; Morugán, A.; García-Orenes, F.; Zornoza, R.; Mataix-Solera, J.; Navarro, M. A.; Guerrero, C.; Mataix-Beneyto, J.

    2009-04-01

    The use of treated wastewater for the irrigation of agricultural soils is an alternative to utilizing better-quality water, especially in semiarid regions where water shortage is a very serious problem. However, this practise can modify the soil equilibrium and affect its quality. In this work two soil quality indices (models) are used to evaluate the effects of long-term irrigation with treated wastewater in soil. The models were developed studying different soil properties in undisturbed forest soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. Model 1, that explained 92% of the variance in soil organic carbon (SOC) showed that the SOC can be calculated by the linear combination of 6 physical, chemical and biochemical properties (acid phosphatase, water holding capacity (WHC), electrical conductivity (EC), available phosphorus (P), cation exchange capacity (CEC) and aggregate stability (AS)). Model 2 explains 89% of the SOC variance, which can be calculated by means of 7 chemical and biochemical properties (urease, phosphatase, and

  7. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems

    PubMed Central

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha−1 yr−1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content. PMID:26759192

  8. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems.

    PubMed

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha(-1) yr(-1), with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content. PMID:26759192

  9. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems

    NASA Astrophysics Data System (ADS)

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha‑1 yr‑1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.

  10. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems

    NASA Astrophysics Data System (ADS)

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha-1 yr-1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.

  11. Can conservation agriculture reduce the impact of soil erosion in northern Tunisia ?

    NASA Astrophysics Data System (ADS)

    Bahri, Haithem; Annabi, Mohamed; Chibani, Roukaya; Cheick M'Hamed, Hatem; Hermessi, Taoufik

    2016-04-01

    Mediterranean countries are prone to soil erosion, therefore Tunisia, with Mediterranean climate, is threatened by water erosion phenomena. In fact, 3 million ha of land is threatened by erosion, and 50% is seriously affected. Soils under conservation agriculture (CA) have high water infiltration capacities reducing significantly surface runoff and thus soil erosion. This improves the quality of surface water, reduces pollution from soil erosion, and enhances groundwater resources. CA is characterized by three interlinked principles, namely continuous minimum mechanical soil disturbance, permanent organic soil cover and diversification of crop species grown in sequence or associations. Soil aggregate stability was used as an indicator of soil susceptibility to water erosion. Since 1999, In Tunisia CA has been introduced in rainfed cereal areas in order to move towards more sustainable agricultural systems. CA areas increased from 52 ha in 1999 to 15000 ha in 2015. The objective of this paper is to study the effect of CA on soil erosion in northern Tunisia. Soil samples were collected at 10 cm of depth from 6 farmers' fields in northern Tunisia. Conventional tillage (CT), CA during less than 5 years (CA<5 years) and CA during more than 5 years (CA>5 years) have been practiced in each farmers field experiment of wheat crop. Soil aggregate stability was evaluated according to the method described by Le Bissonnais (1996), results were expressed as a mean weight diameter (MWD); higher values of MWD indicate higher aggregate stability. Total organic carbon (TOC) was determined using the wet oxidation method of Walkley-Black. A significant increase in SOC content was observed in CA>5years (1.64 %) compared to CT (0.97 %). This result highlights the importance of CA to improve soil fertility. For aggregate stability, a net increase was observed in CA compared to CT. After 5 years of CA the MWD was increased by 16% (MWD=1.8 mm for CT and MWD=2.1 mm for CA<5years). No

  12. Digital spatial soil and land information for agriculture development

    NASA Astrophysics Data System (ADS)

    Sharma, R. K.; Laghathe, Pankaj; Meena, Ranglal; Barman, Alok Kumar; Das, Satyendra Nath

    2006-12-01

    Natural resource management calls for study of natural system prevailing in the country. In India floods and droughts visit regularly, causing extensive damages of natural wealth including agriculture that are crucial for sustenance of economic growth. The Indian Sub-continent drained by many major rivers and their tributaries where watershed, the hydrological unit forms a natural system that allows management and development of land resources following natural harmony. Acquisition of various kinds and levels of soil and land characteristics using both conventional and remote sensing techniques and subsequent development of digital spatial data base are essential to evolve strategy for planning watershed development programmes, their monitoring and impact evaluation. The multi-temporal capability of remote sensing sensors helps to update the existing data base which are of dynamic in nature. The paper outlines the concept of spatial data base development, generation using remote sensing techniques, designing of data structure, standardization and integration with watershed layers and various non spatial attribute data for various applications covering watershed development planning, alternate land use planning, soil and water conservation, diversified agriculture practices, generation of soil health card, soil and land reclamation, etc. The soil and land characteristics are vital to derive various interpretative groupings or master table that helps to generate the desired level of information of various clients using the GIS platform. The digital spatial data base on soils and watersheds generated by All India Soil and Land Use Survey will act as a sub-server of the main GIS based Web Server being hoisted by the planning commission for application of spatial data for planning purposes under G2G domain. It will facilitate e-governance for natural resource management using modern technology.

  13. Assessing the soil microbial carbon budget: Probing with salt stress

    NASA Astrophysics Data System (ADS)

    Rath, Kristin; Rousk, Johannes

    2014-05-01

    The amount of carbon stored as soil organic matter (SOM) constitutes a pool more than double the size of the atmospheric carbon pool. Soil respiration represents one of the largest fluxes of carbon between terrestrial ecosystems and the atmosphere. A large fraction of the CO2 released by soils is produced by the microbial decomposition of SOM. The microbial carbon budget is characterized by their carbon use efficiency, i.e. the partitioning of substrate into growth and respiration. This will shape the role of the soil as a net source or sink for carbon. One of the canonical factors known to influence microbial processes in soil is pH. In aquatic systems salinity has been found to have a comparably strong influence as pH. However salinity remains understudied in soil, despite its growing relevance due to land use change and agricultural practices. The aim of this project is to understand how microbial carbon dynamics respond to disturbance by changing environmental conditions, using salinity as a reversible stressor. First, we compiled a comparative analysis of the sensitivity of different microbial processes to increasing salt concentrations. Second, we compared different salts to determine whether salt toxicity depended on the identity of the salt. Third, we used samples from a natural salinity gradient to assess if a legacy of salt exposure can influence the microbial response to changing salt concentrations. If salt had an ecologically significant effect in shaping these communities, we would assume that microbial processes would be less sensitive to an increase in salt concentrations. The sensitivity of microbial processes to salt was investigated by establishing inhibition curves in order to estimate EC50 values (the concentration resulting in 50% inhibition). These EC50 values were used to compare bacterial and fungal growth responses, as well as catabolic processes such as respiration and nitrogen mineralisation. Initial results suggest that growth related

  14. Use of airborne hyperspectral imagery to map soil parameters in tilled agricultural fields

    USGS Publications Warehouse

    Hively, W. Dean; McCarty, Gregory W.; Reeves, James B.; Lang, Megan W.; Oesterling, Robert A.; Delwiche, Stephen R.

    2011-01-01

    Soil hyperspectral reflectance imagery was obtained for six tilled (soil) agricultural fields using an airborne imaging spectrometer (400–2450 nm, ~10 nm resolution, 2.5 m spatial resolution). Surface soil samples (n = 315) were analyzed for carbon content, particle size distribution, and 15 agronomically important elements (Mehlich-III extraction). When partial least squares (PLS) regression of imagery-derived reflectance spectra was used to predict analyte concentrations, 13 of the 19 analytes were predicted with R2 > 0.50, including carbon (0.65), aluminum (0.76), iron (0.75), and silt content (0.79). Comparison of 15 spectral math preprocessing treatments showed that a simple first derivative worked well for nearly all analytes. The resulting PLS factors were exported as a vector of coefficients and used to calculate predicted maps of soil properties for each field. Image smoothing with a 3 × 3 low-pass filter prior to spectral data extraction improved prediction accuracy. The resulting raster maps showed variation associated with topographic factors, indicating the effect of soil redistribution and moisture regime on in-field spatial variability. High-resolution maps of soil analyte concentrations can be used to improve precision environmental management of farmlands.

  15. Environmental Fate of Double-Stranded RNA in Agricultural Soils

    PubMed Central

    Dubelman, Samuel; Fischer, Joshua; Zapata, Fatima; Huizinga, Kristin; Jiang, Changjian; Uffman, Joshua; Levine, Steven; Carson, David

    2014-01-01

    A laboratory soil degradation study was conducted to determine the biodegradation potential of a DvSnf7 dsRNA transcript derived from a Monsanto genetically modified (GM) maize product that confers resistance to corn rootworm (CRW; Diabrotica spp.). This study provides new information to improve the environmental assessment of dsRNAs that become pesticidal through an RNAi process. Three agricultural soils differing in their physicochemical characteristics were obtained from the U.S., Illinois (IL; silt loam), Missouri (MO; loamy sand) and North Dakota (ND; clay loam), and exposed to the target dsRNA by incorporating insect-protected maize biomass and purified (in vitro-transcribed) DvSnf7 RNA into soil. The GM and control (non-GM maize) materials were added to each soil and incubated at ca. 22°C for 48 hours (h). Samples were collected at 12 time intervals during the incubation period, extracted, and analyzed using QuantiGene molecular analysis and insect bioassay methods. The DT50 (half-life) values for DvSnf7 RNA in IL, MO, and ND soils were 19, 28, and 15 h based on QuantiGene, and 18, 29, and 14 h based on insect bioassay, respectively. Furthermore, the DT90 (time to 90% degradation) values for DvSnf7 RNA in all three soils were <35 h. These results indicate that DvSnf7 RNA was degraded and biological activity was undetectable within approximately 2 days after application to soil, regardless of texture, pH, clay content and other soil differences. Furthermore, soil-incorporated DvSnf7 RNA was non-detectable in soil after 48 h, as measured by QuantiGene, at levels ranging more than two orders of magnitude (0.3, 1.5, 7.5 and 37.5 µg RNA/g soil). Results from this study indicate that the DvSnf7 dsRNA is unlikely to persist or accumulate in the environment. Furthermore, the rapid degradation of DvSnf7 dsRNA provides a basis to define relevant exposure scenarios for future RNA-based agricultural products. PMID:24676387

  16. Sewage sludge applied to agricultural soil: Ecotoxicological effects on representative soil organisms.

    PubMed

    Carbonell, G; Pro, J; Gómez, N; Babín, M M; Fernández, C; Alonso, E; Tarazona, J V

    2009-05-01

    Application of sewage sludge to agricultural lands is a current practice in EU. European legislation permits its use when concentrations of metals in soil do not increase above the maximum permissible limits. In order to assess the fate and the effects on representative soil organisms of sewage sludge amendments on agricultural lands, a soil microcosm (multi-species soil system-MS3) experiment was performed. The MS3 columns were filled with spiked soil at three different doses: 30, 60 and 120tha(-1) fresh wt. Seed plants (Triticum aestivum, Vicia sativa and Brassica rapa) and earthworms (Eisenia fetida) were introduced into the systems. After a 21-d exposure period, a statistically significant increase for Cd, Cu, Zn and Hg concentrations was found for the soils treated with the highest application rate. Dose-related increase was observed for nickel concentrations in leachates. Plants and earthworm metal body burden offer much more information than metal concentrations and help to understand the potential for metal accumulation. Bioaccumulation factor (BAF(plant-soil)) presented a different behavior among species and large differences for BAF(earthworm-soil), from control or sewage-amended soil, for Cd and Hg were found. B. rapa seed germination was reduced. Statistically significant decrease in fresh biomass was observed for T. aestivum and V. sativa at the highest application rate, whereas B. rapa biomass decreased at any application rate. Enzymatic activities (dehydrogenase and phosphatase) as well as respiration rate on soil microorganisms were enlarged.

  17. Soil-Atmosphere CO Exchanges and Microbial Biogeochemistry of CO Transformations in a Brazilian Agricultural Ecosystem†

    PubMed Central

    King, Gary M.; Hungria, M.

    2002-01-01

    Although anthropogenic land use has major impacts on the exchange of soil and atmosphere gas in general, relatively little is known about its impacts on carbon monoxide. We compared soil-atmosphere CO exchanges as a function of land use, crop type, and tillage treatment on an experimental farm in Parãna, Brazil, that is representative of regionally important agricultural ecosystems. Our results showed that cultivated soils consumed CO at rates between 3 and 6 mg of CO m−2 day−1, with no statistically significant effect of tillage method or crop. However, CO exchange for a pasture soil was near zero, and an unmanaged woodlot emitted CO at a rate of 9 mg of CO m−2 day−1. Neither nitrite, aluminum sulfate, nor methyl fluoride additions affected CO consumption by tilled or untilled soils from soybean plots, indicating that CO oxidation did not depend on ammonia oxidizers and that CO oxidation patterns differed in part from patterns reported for forest soils. The apparent Km for CO uptake, 5 to 11 ppm, was similar to values reported for temperate forest soils; Vmax values, approximately 1 μg of CO g (dry weight)−1 h−1, were comparable for woodlot and cultivated soils in spite of the fact that the latter consumed CO under ambient conditions. Short-term (24-h) exposure to elevated levels of CO (10% CO) partially inhibited uptake at lower concentrations (i.e., 100 ppm), suggesting that the sensitivity to CO of microbial populations that are active in situ differs from that of known carboxydotrophs. Soil-free soybean and corn roots consumed CO when they were incubated with 100-ppm concentrations and produced CO when they were incubated with ambient concentrations. These results document for the first time a role for cultivated plant roots in the dynamics of CO in an agricultural ecosystem. PMID:12200303

  18. Snowcover Influences Upon Episodic Release of Nitrous Oxide from Agricultural Soils During Spring Thaw

    NASA Astrophysics Data System (ADS)

    Helgason, W.; Farrell, R.; Ens, J.; Lemke, R.; David, C.

    2015-12-01

    In regions where agricultural soils seasonally freeze, such as the Canadian prairies, up to 60-70% of the annual nitrous oxide (N2O) emission can occur during the soil thaw period. The conditions responsible for this episodic release of N2O are poorly understood. In order to elucidate the influencing factors a replicated plot study was conducted in Outlook, Saskatchewan, Canada (51.5°N) during the 2014-2015 winter period. The study compared soil thermal conditions and soil gas fluxes (nitrous oxide and carbon dioxide) from plots that had the snow periodically removed and those on which snow was allowed to accumulate. Soil gas fluxes were measured using an automated chamber system (Gasmet DX4030 FTIR analyzer and Licor Li-8100 chamber system) and analyzer. Soil conditions were continuously monitored throughout the winter and thaw periods. Owing to the insulating effect of snow, the snow free plots were colder during the mid-winter period, but thawed 3-4 days earlier than the snow covered treatment. Following thaw, the snow-free plots were 2-3 degrees warmer than the snow-covered plots for 5-7 days before reaching a similar thermal regime. Due to the differences in the timing of soil thaw and the pre- and post-thaw thermal conditions, cumulative and peak N2O emissions were much higher from the plots that had been kept snow-free. These results suggest that agricultural practices which influence snow redistribution may have an effect upon spring soil gas fluxes. This study also highlights the importance of incorporating snowmelt and soil thaw physics into process-based greenhouse gas models.

  19. Determine metrics and set targets for soil quality on agriculture residue and energy crop pathways

    SciTech Connect

    Ian Bonner; David Muth

    2013-09-01

    There are three objectives for this project: 1) support OBP in meeting MYPP stated performance goals for the Sustainability Platform, 2) develop integrated feedstock production system designs that increase total productivity of the land, decrease delivered feedstock cost to the conversion facilities, and increase environmental performance of the production system, and 3) deliver to the bioenergy community robust datasets and flexible analysis tools for establishing sustainable and viable use of agricultural residues and dedicated energy crops. The key project outcome to date has been the development and deployment of a sustainable agricultural residue removal decision support framework. The modeling framework has been used to produce a revised national assessment of sustainable residue removal potential. The national assessment datasets are being used to update national resource assessment supply curves using POLYSIS. The residue removal modeling framework has also been enhanced to support high fidelity sub-field scale sustainable removal analyses. The framework has been deployed through a web application and a mobile application. The mobile application is being used extensively in the field with industry, research, and USDA NRCS partners to support and validate sustainable residue removal decisions. The results detailed in this report have set targets for increasing soil sustainability by focusing on primary soil quality indicators (total organic carbon and erosion) in two agricultural residue management pathways and a dedicated energy crop pathway. The two residue pathway targets were set to, 1) increase residue removal by 50% while maintaining soil quality, and 2) increase soil quality by 5% as measured by Soil Management Assessment Framework indicators. The energy crop pathway was set to increase soil quality by 10% using these same indicators. To demonstrate the feasibility and impact of each of these targets, seven case studies spanning the US are presented

  20. Carbon sequestration in agricultural lands of the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing concentrations of greenhouse gases has been identified as one of the most pressing modern-day environment issues. In agricultural systems, the sequestering of C in mostly soils is thought to be one of the best options for reducing atmospheric concentrations of one of the most important gree...

  1. Estimating the distribution of radionuclides in agricultural soils - dependence on soil parameters.

    PubMed

    Hormann, Volker; Fischer, Helmut W

    2013-10-01

    In this study it is shown how radionuclide distributions in agricultural soils and their dependence on soil parameters can be quantitatively estimated. The most important sorption and speciation processes have been implemented into a numerical model using the geochemical code PHREEQC that is able to include specific soil and soil solution compositions. Using this model, distribution coefficients (Kd values) for the elements Cs, Ni, U and Se have been calculated for two different soil types. Furthermore, the dependencies of these Kd values on various soil parameters (e.g. pH value or organic matter content) have been evaluated. It is shown that for each element, an individual set of soil parameters is relevant for its solid-liquid distribution. The model may be used for the calculation of input parameters used by reference biosphere models (e.g. used for the risk assessment of nuclear waste repositories). PMID:23871968

  2. Estimating the distribution of radionuclides in agricultural soils - dependence on soil parameters.

    PubMed

    Hormann, Volker; Fischer, Helmut W

    2013-10-01

    In this study it is shown how radionuclide distributions in agricultural soils and their dependence on soil parameters can be quantitatively estimated. The most important sorption and speciation processes have been implemented into a numerical model using the geochemical code PHREEQC that is able to include specific soil and soil solution compositions. Using this model, distribution coefficients (Kd values) for the elements Cs, Ni, U and Se have been calculated for two different soil types. Furthermore, the dependencies of these Kd values on various soil parameters (e.g. pH value or organic matter content) have been evaluated. It is shown that for each element, an individual set of soil parameters is relevant for its solid-liquid distribution. The model may be used for the calculation of input parameters used by reference biosphere models (e.g. used for the risk assessment of nuclear waste repositories).

  3. Comparative resistance and resilience of soil microbial communities and enzyme activities in adjacent native forest and agricultural soils.

    PubMed

    Chaer, Guilherme; Fernandes, Marcelo; Myrold, David; Bottomley, Peter

    2009-08-01

    Degradation of soil properties following deforestation and long-term soil cultivation may lead to decreases in soil microbial diversity and functional stability. In this study, we investigated the differences in the stability (resistance and resilience) of microbial community composition and enzyme activities in adjacent soils under either native tropical forest (FST) or in agricultural cropping use for 14 years (AGR). Mineral soil samples (0 to 5 cm) from both areas were incubated at 40 degrees C, 50 degrees C, 60 degrees C, or 70 degrees C for 15 min in order to successively reduce the microbial biomass. Three and 30 days after the heat shocks, fluorescein diacetate (FDA) hydrolysis, cellulase and laccase activities, and phospholipid-derived fatty acids-based microbial community composition were measured. Microbial biomass was reduced up to 25% in both soils 3 days after the heat shocks. The higher initial values of microbial biomass, enzyme activity, total and particulate soil organic carbon, and aggregate stability in the FST soil coincided with higher enzymatic stability after heat shocks. FDA hydrolysis activity was less affected (more resistance) and cellulase and laccase activities recovered more rapidly (more resilience) in the FST soil relative to the AGR counterpart. In the AGR soil, laccase activity did not show resilience to any heat shock level up to 30 days after the disturbance. Within each soil type, the microbial community composition did not differ between heat shock and control samples at day 3. However, at day 30, FST soil samples treated at 60 degrees C and 70 degrees C contained a microbial community significantly different from the control and with lower biomass regardless of high enzyme resilience. Results of this study show that deforestation followed by long-term cultivation changed microbial community composition and had differential effects on microbial functional stability. Both soils displayed similar resilience to FDA hydrolysis, a

  4. Comparative resistance and resilience of soil microbial communities and enzyme activities in adjacent native forest and agricultural soils.

    PubMed

    Chaer, Guilherme; Fernandes, Marcelo; Myrold, David; Bottomley, Peter

    2009-08-01

    Degradation of soil properties following deforestation and long-term soil cultivation may lead to decreases in soil microbial diversity and functional stability. In this study, we investigated the differences in the stability (resistance and resilience) of microbial community composition and enzyme activities in adjacent soils under either native tropical forest (FST) or in agricultural cropping use for 14 years (AGR). Mineral soil samples (0 to 5 cm) from both areas were incubated at 40 degrees C, 50 degrees C, 60 degrees C, or 70 degrees C for 15 min in order to successively reduce the microbial biomass. Three and 30 days after the heat shocks, fluorescein diacetate (FDA) hydrolysis, cellulase and laccase activities, and phospholipid-derived fatty acids-based microbial community composition were measured. Microbial biomass was reduced up to 25% in both soils 3 days after the heat shocks. The higher initial values of microbial biomass, enzyme activity, total and particulate soil organic carbon, and aggregate stability in the FST soil coincided with higher enzymatic stability after heat shocks. FDA hydrolysis activity was less affected (more resistance) and cellulase and laccase activities recovered more rapidly (more resilience) in the FST soil relative to the AGR counterpart. In the AGR soil, laccase activity did not show resilience to any heat shock level up to 30 days after the disturbance. Within each soil type, the microbial community composition did not differ between heat shock and control samples at day 3. However, at day 30, FST soil samples treated at 60 degrees C and 70 degrees C contained a microbial community significantly different from the control and with lower biomass regardless of high enzyme resilience. Results of this study show that deforestation followed by long-term cultivation changed microbial community composition and had differential effects on microbial functional stability. Both soils displayed similar resilience to FDA hydrolysis, a

  5. ESTABLISHING A SOIL CARBON BASELINE FOR CARBON ACCOUNTING THE FORESTED SOILS OF THE UNITED STATES

    EPA Science Inventory

    Soils are an important global reservoir of organic carbon (C). It has been estimated that at 1500 Pg world soils hold approximately three times the amount of C held in vegetation and two times that in the atmosphere. Soils provide a relatively stable reservoir for C. With the int...

  6. The Influence of Landscape Drainage on Biogeochemical Cycling of Carbon in Agricultural Ecosystems

    NASA Astrophysics Data System (ADS)

    Dalzell, B. J.; King, J. Y.; Mulla, D. J.; Finlay, J. C.; Sands, G. R.

    2008-12-01

    The movement of water through agricultural ecosystems is often modified by the presence of open ditches and subsurface tile drainage systems. Despite the common occurrence of these practices, particularly in the corn- and soybean-producing regions of the midwestern United States, much remains unknown about how altered drainage patterns may influence carbon export from agricultural landscapes. In this study, we examined the role of subsurface drainage systems on the quantity and quality of dissolved carbon export from experimental agricultural fields located in south-central Minnesota. Results from two years of observations show that fields with more intense drainage designs (e.g., greater density of subsurface drain lines) have dissolved organic carbon (DOC) concentrations that are similar to conventionally drained fields. However, fields with more intense drainage exhibit greater annual DOC loads due to higher water yields resulting from more intense drainage. In contrast, dissolved inorganic carbon (DIC) concentrations were consistently greater in fields with more intense drainage practices across all flow conditions. Our ongoing work is focused on determining if these differences in DIC concentrations are the result of either increased weathering or increased soil/plant root respiration resulting in increased soil CO2 concentrations. Molecular weight characterization of samples from our experimental fields shows that DOC from subsurface tile drainage is generally comprised of low molecular weight compounds. This low molecular weight signal is less apparent in samples from downstream ditch and river sites which are dominated by higher molecular weight compounds; suggesting that differences in organic matter source and/or processing are apparent over spatial scales transitioning from the field to small watershed. Overall, these results show that subsurface drainage practices fundamentally alter annual DOC and DIC carbon export from agricultural ecosystems as well

  7. Switchgrass cultivars differentially affect soil carbon stabilization

    NASA Astrophysics Data System (ADS)

    Adkins, J.; Jastrow, J. D.; Wullschleger, S. D.; De Graaff, M.

    2012-12-01

    Soil organic carbon (SOC) storage depends on the amount and quality of plant-derived carbon (C) inputs to soil, which is largely regulated by plant roots via the processes of root turnover and exudation. While we know that plant roots mediate SOC stabilization, we do not fully understand which root characteristics specifically promote soil C storage. With this study we asked whether roots with coarse root systems versus roots with finely branched root systems differentially affect soil C stabilization. In order to answer this question, we collected soil cores (4.8 cm diameter, to a depth of 30 cm) from directly over the crown of six switchgrass (Panicum virgatum L.) cultivars that differed in root architecture. Specifically, three cultivars had fibrous root systems (i.e. high specific root length) and three had coarse root systems (i.e. low specific root length). The cultivars (C4 species) were grown in a C3 grassland for four years, allowing us to use isotopic fractionation techniques to assess differences in soil C input and stabilization. The cores were divided into depth increments of 10 cm and the soils were sieved (2mm). Soil from each depth increment was dispersed by shaking for 16 hours in a NaHMP solution to isolate coarse particulate organic matter (C-POM), fine particulate organic matter (F-POM), silt, and clay-sized fractions. Samples of soil fractions across all depths were analyzed for C and N contents as well as δ13C signature. We found that the relative abundance of the different soil fractions and associated δ13C signatures differed significantly among cultivars. These results indicate that switchgrass cultivars can differentially impact soil carbon inputs and stabilization. We hypothesize that these differences may be driven by variability in root architectures.

  8. Nitrogen Turnover Processes in Low Temperatures in an Agricultural Peat Soil

    NASA Astrophysics Data System (ADS)

    Silvennoinen, H. M.; Hämäläinen, R.; Koponen, H. T.; Martikainen, P. J.

    2009-12-01

    Nitrogen (N) cycling in agricultural soils has a key impact on the environment. Agricultural ecosystems are the most important sources of nitrous oxide (N2O), an important greenhouse gas, to the atmosphere. Additionally N fertilizers used to improve plant growth lead to enhanced N leaching and thereby to eutrophication of surrounding aquatic ecosystems. Microbial processes are normally enhanced by increase in temperature. Several recent studies have shown that although N2O emissions from agricultural soils are of microbiological origin, produced mainly in microbial reduction of nitrate (NO3-) via nitric oxide (NO) and N2O to molecular nitrogen (N2) (denitrification), the temperature response of N2O emissions is greatly variable and there is a lot of evidence of high emissions during cold periods (Koponen et al. 2006). Denitrification is, however, regulated by availability of inorganic N and therefore dependant not only on N fertilization but also on N turnover processes in soil. These processes include mineralization of organic N to ammonium (NH4+), oxidation of NH4+ to nitrite and NO3- (nitrification). These processes and their regulation especially in low temperatures are yet poorly understood. In this experiment, gross rates of N mineralization and nitrification and carbon dioxide production were studied in various temperatures ranging from -1.5 to 15 °C. Soil samples were taken from grassland on peat soil in Southern Finland (60o49’N, 23o30’E) on September 8th 2008 from depths of 0-10 cm. Temperature responses of N gross mineralization and nitrification and of microbial respiration were measured in a laboratory experiment. The incubation temperatures used for experiments were 15, 5, 2.5, 1.5, 0.5, 0, -0.5 and -1.5 °C. After 7 d temperature-specific incubation, gross rates of N mineralization and nitrification were determined with pool dilution technique in a 24 h incubation experiment. This study showed that N turnover processes in agricultural peat soil

  9. Carbon storage after long-term grass establishment on degraded soils

    SciTech Connect

    Potter, K.N.; Torbert, H.A.; Johnson, H.B.; Tischler, C.R.

    1999-10-01

    Recent concern about global warming has led to attempts to estimate the effects of management on carbon sequestration in soil. The objective of this study is to determine the amount of soil organic carbon (SOC) degraded by agricultural practices and the rate of carbon sequestration in soils after restoration of grass for various periods of time. The SOC contents of previously cultivated clay soils (Udic Haplusterts) in central Texas returned to grass 6, 26, and 60 years ago are compared with those of soils in continuous agriculture for more than 100 years and those of prairie soils that have never been tilled. Surface (0 to 5 cm) SOC concentration ranged from 4.44 to 5.95% in the prairie to 1.53 to 1.88% in the agricultural sites. Carbon concentration in restored grasslands was generally intermediate to that reported for the native prairie and agricultural sites. The SOC mass in the surface 120 cm of the agricultural soils was 25 to 43% less than that of native prairie sites. After the establishment of grasses, SOC mass in the grass sites was greater than at the agricultural sites. A linear relationship between the length of time in grass and the amount of SOC sequestered in the surface 60 cm fit well for time periods from 6 to 60 years. The slope of this function provided an estimate of the carbon sequestration rate, in this case 447 kg C ha{sup {minus}1} yr{sup {minus}1}. At this rate, it would require nearly an additional century (98 years) for the 60-year grass site to reach a carbon pool equivalent to that of the prairie.

  10. Changes in soil carbon, nitrogen, and phosphorus due to land-use changes in Brazil

    NASA Astrophysics Data System (ADS)

    Groppo, J. D.; Lins, S. R. M.; Camargo, P. B.; Assad, E. D.; Pinto, H. S.; Martins, S. C.; Salgado, P. R.; Evangelista, B.; Vasconcellos, E.; Sano, E. E.; Pavão, E.; Luna, R.; Martinelli, L. A.

    2015-08-01

    In this paper, soil carbon, nitrogen and phosphorus concentrations and stocks were investigated in agricultural and natural areas in 17 plot-level paired sites and in a regional survey encompassing more than 100 pasture soils In the paired sites, elemental soil concentrations and stocks were determined in native vegetation (forests and savannas), pastures and crop-livestock systems (CPSs). Nutrient stocks were calculated for the soil depth intervals 0-10, 0-30, and 0-60 cm for the paired sites and 0-10, and 0-30 cm for the pasture regional survey by sum stocks obtained in each sampling intervals (0-5, 5-10, 10-20, 20-30, 30-40, 40-60 cm). Overall, there were significant differences in soil element concentrations and ratios between different land uses, especially in the surface soil layers. Carbon and nitrogen contents were lower, while phosphorus contents were higher in the pasture and CPS soils than in native vegetation soils. Additionally, soil stoichiometry has changed with changes in land use. The soil C : N ratio was lower in the native vegetation than in the pasture and CPS soils, and the carbon and nitrogen to available phosphorus ratio (PME) decreased from the native vegetation to the pasture to the CPS soils. In the plot-level paired sites, the soil nitrogen stocks were lower in all depth intervals in pasture and in the CPS soils when compared with the native vegetation soils. On the other hand, the soil phosphorus stocks were higher in all depth intervals in agricultural soils when compared with the native vegetation soils. For the regional pasture survey, soil nitrogen and phosphorus stocks were lower in all soil intervals in pasture soils than in native vegetation soils. The nitrogen loss with cultivation observed here is in line with other studies and it seems to be a combination of decreasing organic matter inputs, in cases where crops replaced native forests, with an increase in soil organic matter decomposition that leads to a decrease in the long

  11. Value of Available Global Soil Moisture Products for Agricultural Monitoring

    NASA Astrophysics Data System (ADS)

    Mladenova, Iliana; Bolten, John; Crow, Wade; de Jeu, Richard

    2016-04-01

    The first operationally derived and publicly distributed global soil moil moisture product was initiated with the launch of the Advanced Scanning Microwave Mission on the NASA's Earth Observing System Aqua satellite (AMSR-E). AMSR-E failed in late 2011, but its legacy is continued by AMSR2, launched in 2012 on the JAXA Global Change Observation Mission-Water (GCOM-W) mission. AMSR is a multi-frequency dual-polarization instrument, where the lowest two frequencies (C- and X-band) were used for soil moisture retrieval. Theoretical research and small-/field-scale airborne campaigns, however, have demonstrated that soil moisture would be best monitored using L-band-based observations. This consequently led to the development and launch of the first L-band-based mission-the ESA's Soil Moisture Ocean Salinity (SMOS) mission (2009). In early 2015 NASA launched the second L-band-based mission, the Soil Moisture Active Passive (SMAP). These satellite-based soil moisture products have been demonstrated to be invaluable sources of information for mapping water stress areas, crop monitoring and yield forecasting. Thus, a number of agricultural agencies routinely utilize and rely on global soil moisture products for improving their decision making activities, determining global crop production and crop prices, identifying food restricted areas, etc. The basic premise of applying soil moisture observations for vegetation monitoring is that the change in soil moisture conditions will precede the change in vegetation status, suggesting that soil moisture can be used as an early indicator of expected crop condition change. Here this relationship was evaluated across multiple microwave frequencies by examining the lag rank cross-correlation coefficient between the soil moisture observations and the Normalized Difference Vegetation Index (NDVI). A main goal of our analysis is to evaluate and inter-compare the value of the different soil moisture products derived using L-band (SMOS

  12. Argonne Terrestrial Carbon Cycle Data from Batavia Prairie and Agricultural Sites

    DOE Data Explorer

    Matamala, Roser [ANL; Jastrow, Julie D.; Lesht, Barry [ANL; Cook, David [ANL; Pekour, Mikhail [ANL; Gonzalez-Meler, Miquel A. [University of Illinois at Chicago

    Carbon dioxide fluxes and stocks in terrestrial ecosystems are key measurements needed to constrain quantification of regional carbon sinks and sources and the mechanisms controlling them. This information is required to produce a sound carbon budget for North America. This project examines CO2 and energy fluxes from agricultural land and from restored tallgrass prairie to compare their carbon sequestration potentials. The study integrates eddy covariance measurements with biometric measurements of plant and soil carbon stocks for two systems in northeastern Illinois: 1) long-term cultivated land in corn-soybean rotation with conventional tillage, and 2) a 15 year-old restored prairie that represents a long-term application of CRP conversion of cultivated land to native vegetation. The study contributes to the North American Carbon Program (NACP) by providing information on the magnitude and distribution of carbon stocks and the processes that control carbon dynamics in cultivated and CRP-restored land in the Midwest. The prairie site has been functioning since October 2004 and the agricultural site since July 2005. (From http://www.atmos.anl.gov/ FERMI/index.html)

  13. Effect of integrating straw into agricultural soils on soil infiltration and evaporation.

    PubMed

    Cao, Jiansheng; Liu, Changming; Zhang, Wanjun; Guo, Yunlong

    2012-01-01

    Soil water movement is a critical consideration for crop yield in straw-integrated fields. This study used an indoor soil column experiment to determine soil infiltration and evaporation characteristics in three forms of direct straw-integrated soils (straw mulching, straw mixing and straw inter-layering). Straw mulching is covering the land surface with straw. Straw mixing is mixing straw with the top 10 cm surface soil. Then straw inter-layering is placing straw at the 20 cm soil depth. There are generally good correlations among the mulch integration methods at p < 0.05, and with average errors/biases <10%. Straw mixing exhibited the best effect in terms of soil infiltration, followed by straw mulching. Due to over-burden weight-compaction effect, straw inter-layering somehow retarded soil infiltration. In terms of soil water evaporation, straw mulching exhibited the best effect. This was followed by straw mixing and then straw inter-layering. Straw inter-layering could have a long-lasting positive effect on soil evaporation as it limited the evaporative consumption of deep soil water. The responses of the direct straw integration modes to soil infiltration and evaporation could lay the basis for developing efficient water-conservation strategies. This is especially useful for water-scarce agricultural regions such as the arid/semi-arid regions of China.

  14. Effect of integrating straw into agricultural soils on soil infiltration and evaporation.

    PubMed

    Cao, Jiansheng; Liu, Changming; Zhang, Wanjun; Guo, Yunlong

    2012-01-01

    Soil water movement is a critical consideration for crop yield in straw-integrated fields. This study used an indoor soil column experiment to determine soil infiltration and evaporation characteristics in three forms of direct straw-integrated soils (straw mulching, straw mixing and straw inter-layering). Straw mulching is covering the land surface with straw. Straw mixing is mixing straw with the top 10 cm surface soil. Then straw inter-layering is placing straw at the 20 cm soil depth. There are generally good correlations among the mulch integration methods at p < 0.05, and with average errors/biases <10%. Straw mixing exhibited the best effect in terms of soil infiltration, followed by straw mulching. Due to over-burden weight-compaction effect, straw inter-layering somehow retarded soil infiltration. In terms of soil water evaporation, straw mulching exhibited the best effect. This was followed by straw mixing and then straw inter-layering. Straw inter-layering could have a long-lasting positive effect on soil evaporation as it limited the evaporative consumption of deep soil water. The responses of the direct straw integration modes to soil infiltration and evaporation could lay the basis for developing efficient water-conservation strategies. This is especially useful for water-scarce agricultural regions such as the arid/semi-arid regions of China. PMID:22643418

  15. Soil Management Effects on Gas Fluxes from an Organic Soil Agricultural System

    NASA Astrophysics Data System (ADS)

    Jennewein, S. P.; Bhadha, J. H.; Lang, T. A.; Singh, M.; Daroub, S. H.; McCray, M.

    2015-12-01

    The role of soil management on gas flux isn't well understood for Histosols of the Everglades Agricultural Area (EAA) of southern Florida. The region is responsible for roughly half of sugarcane (Saccharum spp. hybrids) production in the USA along with supplying winter vegetable crops to the eastern USA. Future productivity in the EAA is jeopardized by soil subsidence resulting from oxidation of organic matter. Establishing the role of tillage, water-table depth, nitrogen fertilizer, and soil depth on gas flux will help determine how effective various managements are on conserving soil. Ongoing lysimeter and field studies examined effects of management practices (water-table, tillage, and nitrogen fertilizer), and soil depth on, gas emission and microbial biomass. The trials were set in Belle Glade, FL, on Lauderhill muck (Lithic Haplosaprists). Results to be presented include soil microbial biomass and soil gas (CO2, CH4, and N2O) flux. This study provides insight into management effectiveness and agriculture sustainability on shallow muck soils of the EAA and will help farmers mitigate problems associated with soil subsidence and seasonally high water-tables.

  16. Soil, environmental, and watershed measurements in support of carbon cycling studies in northwestern Mississippi

    USGS Publications Warehouse

    Huntington, T.G.; Harden, J.W.; Dabney, S.M.; Marion, D.A.; Alonso, C.; Sharpe, J.M.; Fries, T.L.

    1998-01-01

    Measurements including soil respiration, soil moisture, soil temperature, and carbon export in suspended sediments from small watersheds were recorded at several field sites in northwestern Mississippi in support of hillslope process studies associated with the U.S. Geological Survey's Mississippi Basin Carbon Project (MBCP). These measurements were made to provide information about carbon cycling in agricultural and forest ecosystems to understand the potential role of erosion and deposition in the sequestration of soil organic carbon in upland soils. The question of whether soil erosion and burial constitutes an important net sink of atmospheric carbon dioxide is one hypothesis that the MBCP is evaluating to better understand carbon cycling and climate change. This report contains discussion of methods used and presents data for the period December 1996 through March 1998. Included in the report are ancillary data provided by the U.S. Department of Agriculture (USDA) ARS National Sedimentation Laboratory and U.S. Forest Service (USFS) Center for Bottomland Hardwoods Research on rainfall, runoff, sediment yield, forest biomass and grain yield. Together with the data collected by the USGS these data permit the construction of carbon budgets and the calibration of models of soil organic matter dynamics and sediment transport and deposition. The U.S. Geological Survey (USGS) has established cooperative agreements with the USDA and USFS to facilitate collaborative research at research sites in northwestern Mississippi.

  17. Management of agricultural soils for greenhouse gas mitigation: Learning from a case study in NE Spain.

    PubMed

    Sánchez, B; Iglesias, A; McVittie, A; Álvaro-Fuentes, J; Ingram, J; Mills, J; Lesschen, J P; Kuikman, P J

    2016-04-01

    A portfolio of agricultural practices is now available that can contribute to reaching European mitigation targets. Among them, the management of agricultural soils has a large potential for reducing GHG emissions or sequestering carbon. Many of the practices are based on well tested agronomic and technical know-how, with proven benefits for farmers and the environment. A suite of practices has to be used since none of the practices can provide a unique solution. However, there are limitations in the process of policy development: (a) agricultural activities are based on biological processes and thus, these practices are location specific and climate, soils and crops determine their agronomic potential; (b) since agriculture sustains rural communities, the costs and potential for implementation have also to be regionally evaluated and (c) the aggregated regional potential of the combination of practices has to be defined in order to inform abatement targets. We believe that, when implementing mitigation practices, three questions are important: Are they cost-effective for farmers? Do they reduce GHG emissions? What policies favour their implementation? This study addressed these questions in three sequential steps. First, mapping the use of representative soil management practices in the European regions to provide a spatial context to upscale the local results. Second, using a Marginal Abatement Cost Curve (MACC) in a Mediterranean case study (NE Spain) for ranking soil management practices in terms of their cost-effectiveness. Finally, using a wedge approach of the practices as a complementary tool to link science to mitigation policy. A set of soil management practices was found to be financially attractive for Mediterranean farmers, which in turn could achieve significant abatements (e.g., 1.34 MtCO2e in the case study region). The quantitative analysis was completed by a discussion of potential farming and policy choices to shape realistic mitigation policy at

  18. Management of agricultural soils for greenhouse gas mitigation: Learning from a case study in NE Spain.

    PubMed

    Sánchez, B; Iglesias, A; McVittie, A; Álvaro-Fuentes, J; Ingram, J; Mills, J; Lesschen, J P; Kuikman, P J

    2016-04-01

    A portfolio of agricultural practices is now available that can contribute to reaching European mitigation targets. Among them, the management of agricultural soils has a large potential for reducing GHG emissions or sequestering carbon. Many of the practices are based on well tested agronomic and technical know-how, with proven benefits for farmers and the environment. A suite of practices has to be used since none of the practices can provide a unique solution. However, there are limitations in the process of policy development: (a) agricultural activities are based on biological processes and thus, these practices are location specific and climate, soils and crops determine their agronomic potential; (b) since agriculture sustains rural communities, the costs and potential for implementation have also to be regionally evaluated and (c) the aggregated regional potential of the combination of practices has to be defined in order to inform abatement targets. We believe that, when implementing mitigation practices, three questions are important: Are they cost-effective for farmers? Do they reduce GHG emissions? What policies favour their implementation? This study addressed these questions in three sequential steps. First, mapping the use of representative soil management practices in the European regions to provide a spatial context to upscale the local results. Second, using a Marginal Abatement Cost Curve (MACC) in a Mediterranean case study (NE Spain) for ranking soil management practices in terms of their cost-effectiveness. Finally, using a wedge approach of the practices as a complementary tool to link science to mitigation policy. A set of soil management practices was found to be financially attractive for Mediterranean farmers, which in turn could achieve significant abatements (e.g., 1.34 MtCO2e in the case study region). The quantitative analysis was completed by a discussion of potential farming and policy choices to shape realistic mitigation policy at

  19. Carbon storage in soils of Southeastern Nigeria under different management practices

    PubMed Central

    2010-01-01

    Background Changes in agricultural practices-notably changes in crop varieties, application of fertilizer and manure, rotation and tillage practices-influence how much and at what rate carbon is stored in, or released from, soils. Quantification of the impacts of land use on carbon stocks in sub-Saharan Africa is challenging because of the spatial heterogeneity of soil, climate, management conditions, and due to the lack of data on soil carbon pools of most common agroecosystems. This paper provides data on soil carbon stocks that were collected at 10 sites in southeastern Nigeria to characterize the impact of soil management practices. Results The highest carbon stocks, 7906-9510 gC m-2, were found at the sites representing natural forest, artificial forest and artificial grassland ecosystems. Continuously cropped and conventionally tilled soils had about 70% lower carbon stock (1978-2822 gC m-2). Thus, the soil carbon stock in a 45-year old Gmelina forest was 8987 gC m-2, whereas the parts of this forest, that were cleared and continuously cultivated for 15 years, had 75% lower carbon stock (1978 gC m-2). The carbon stock of continuously cropped and conventionally tilled soils was also 25% lower than the carbon stock of the soil cultivated by use of conservation tillage. Conclusion Introducing conservation tillage practices may reduce the loss of soil carbon stocks associated with land conversion. However, the positive effect of conservation tillage is not comparable to the negative effect of land conversion, and may not result in significant accumulation of carbon in southeastern Nigeria soils. PMID:20868522

  20. Directional reflectance factors for monitoring spatial changes in soil surface structure and soil organic matter erosion in agricultural systems

    NASA Astrophysics Data System (ADS)

    Croft, H.; Anderson, K.

    2012-04-01

    Soils can experience rapid structural degradation in response to land cover changes, resulting in reduced soil productivity, increased erodibility and a loss of soil organic matter (SOM). The breakdown of soil aggregates through slaking and raindrop impact is linked to organic matter turnover, with subsequently eroded material often displaying proportionally more SOM. A reduction in aggregate stability is reflected in a decline in soil surface roughness (SSR), indicating that a soil structural change can be used to highlight soil vulnerability to SOM loss through mineralisation or erosion. Accurate, spatially-continuous measurements of SSR are therefore needed at a variety of spatial and temporal scales to understand the spatial nature of SOM erosion and deposition. Remotely-sensed data can provide a cost-effective means of monitoring changes in soil surface condition over broad spatial extents. Previous work has demonstrated the ability of directional reflectance factors to monitor soil crusting within a controlled laboratory experiment, due to changes in the levels of self-shadowing effects by soil aggregates. However, further research is needed to test this approach in situ, where other soil variables may affect measured reflectance factors and to investigate the use of directional reflectance factors for monitoring soil erosion processes. This experiment assesses the potential of using directional reflectance factors to monitor changes in SSR, aggregate stability and soil organic carbon (SOC) content for two agricultural conditions. Five soil plots representing tilled and seedbed soils were subjected to different durations of natural rainfall, producing a range of different levels of SSR. Directional reflectance factors were measured concomitantly with sampling for soil structural and biochemical tests at each soil plot. Soil samples were taken to measure aggregate stability (wet sieving), SOC (loss on ignition) and soil moisture (gravimetric method). SSM

  1. Assessment of methods for organic and inorganic carbon quantification in carbonate-containing Mediterranean soils

    NASA Astrophysics Data System (ADS)

    Apesteguia, Marcos; Virto, Iñigo; Plante, Alain

    2014-05-01

    Quantification of soil organic matter (SOM) stocks and fluxes continues to be an important endeavor in assessments of soil quality, and more broadly in assessments of ecosystem functioning. The quantification of SOM in alkaline, carbonate-containing soils, such as those found in Mediterranean areas, is complicated by the need to differentiate between organic carbon (OC) and inorganic carbon (IC), which continues to present methodological challenges. Acidification is frequently used to eliminate carbonates prior to soil OC quantification, but when performed in the liquid phase, can promote the dissolution and loss of a portion of the OC. Acid fumigation (AF) is increasingly preferred for carbonate removal, but its effectiveness is difficult to assess using conventional elemental and isotopic analyses. In addition, the potential effects of AF on SOM are not well characterized. The objective of the current study was to apply a multi-method approach to determine the efficacy of carbonate removal by AF and its effects on the residual SOM. We selected a set of 24 surface agricultural soils representing a large range of textures, SOM contents and presumed carbonate contents. For each soil, OC was determined using wet combustion (Walkley-Black) and IC was determined using the calcimeter method. Samples were then subjected to elemental (total C) and isotopic (δ13C) analyses by dry combustion using a Costech autoanalyzer coupled to a Thermo Finnigan Delta Plus isotope ratio mass spectrometer (IRMS) before and after AF. IC was equated to total C determined after fumigation, and OC was estimated as the different in total C before and after AF. Samples were also subjected to ramped oxidation using a Netzsch STA109 PC Luxx thermal analyzer coupled to a LICOR 820A infrared gas analyzer (IRGA). Quantification of OC was performed using evolved gas analysis of CO2 (CO2-EGA) in the exothermic region 200-500° C associated with organic matter combustion. IC was quantified by CO2-EGA

  2. Intercropping enhances soil carbon and nitrogen.

    PubMed

    Cong, Wen-Feng; Hoffland, Ellis; Li, Long; Six, Johan; Sun, Jian-Hao; Bao, Xing-Guo; Zhang, Fu-Suo; Van Der Werf, Wopke

    2015-04-01

    Intercropping, the simultaneous cultivation of multiple crop species in a single field, increases aboveground productivity due to species complementarity. We hypothesized that intercrops may have greater belowground productivity than sole crops, and sequester more soil carbon over time due to greater input of root litter. Here, we demonstrate a divergence in soil organic carbon (C) and nitrogen (N) content over 7 years in a field experiment that compared rotational strip intercrop systems and ordinary crop rotations. Soil organic C content in the top 20 cm was 4% ± 1% greater in intercrops than in sole crops, indicating a difference in C sequestration rate between intercrop and sole crop systems of 184 ± 86 kg C ha(-1) yr(-1). Soil organic N content in the top 20 cm was 11% ± 1% greater in intercrops than in sole crops, indicating a difference in N sequestration rate between intercrop and sole crop systems of 45 ± 10 kg N ha(-1) yr(-1). Total root biomass in intercrops was on average 23% greater than the average root biomass in sole crops, providing a possible mechanism for the observed divergence in soil C sequestration between sole crop and intercrop systems. A lowering of the soil δ(15) N signature suggested that increased biological N fixation and/or reduced gaseous N losses contributed to the increases in soil N in intercrop rotations with faba bean. Increases in soil N in wheat/maize intercrop pointed to contributions from a broader suite of mechanisms for N retention, e.g., complementary N uptake strategies of the intercropped plant species. Our results indicate that soil C sequestration potential of strip intercropping is similar in magnitude to that of currently recommended management practises to conserve organic matter in soil. Intercropping can contribute to multiple agroecosystem services by increased yield, better soil quality and soil C sequestration.

  3. Intercropping enhances soil carbon and nitrogen.

    PubMed

    Cong, Wen-Feng; Hoffland, Ellis; Li, Long; Six, Johan; Sun, Jian-Hao; Bao, Xing-Guo; Zhang, Fu-Suo; Van Der Werf, Wopke

    2015-04-01

    Intercropping, the simultaneous cultivation of multiple crop species in a single field, increases aboveground productivity due to species complementarity. We hypothesized that intercrops may have greater belowground productivity than sole crops, and sequester more soil carbon over time due to greater input of root litter. Here, we demonstrate a divergence in soil organic carbon (C) and nitrogen (N) content over 7 years in a field experiment that compared rotational strip intercrop systems and ordinary crop rotations. Soil organic C content in the top 20 cm was 4% ± 1% greater in intercrops than in sole crops, indicating a difference in C sequestration rate between intercrop and sole crop systems of 184 ± 86 kg C ha(-1) yr(-1). Soil organic N content in the top 20 cm was 11% ± 1% greater in intercrops than in sole crops, indicating a difference in N sequestration rate between intercrop and sole crop systems of 45 ± 10 kg N ha(-1) yr(-1). Total root biomass in intercrops was on average 23% greater than the average root biomass in sole crops, providing a possible mechanism for the observed divergence in soil C sequestration between sole crop and intercrop systems. A lowering of the soil δ(15) N signature suggested that increased biological N fixation and/or reduced gaseous N losses contributed to the increases in soil N in intercrop rotations with faba bean. Increases in soil N in wheat/maize intercrop pointed to contributions from a broader suite of mechanisms for N retention, e.g., complementary N uptake strategies of the intercropped plant species. Our results indicate that soil C sequestration potential of strip intercropping is similar in magnitude to that of currently recommended management practises to conserve organic matter in soil. Intercropping can contribute to multiple agroecos