• Authors:
    • Dondini,M.
    • Jones,E. O.
    • Richards,M.
    • Pogson,M.
    • Rowe,R. L.
    • Keith,A. M.
    • Perks,M. P.
    • McNamara,N. P.
    • Smith,J. U.
    • Smith,P.
  • Source: Global Change Biology
  • Volume: 7
  • Issue: 3
  • Year: 2015
  • Summary: Understanding and predicting the effects of land-use change to short rotation forestry (SRF) on soil carbon (C) is an important requirement for fully assessing the C mitigation potential of SRF as a bioenergy crop. There is little current knowledge of SRF in the UK and in particular a lack of consistent measured data sets on the direct impacts of land use change on soil C stocks. The ECOSSE model was developed to simulate soil C dynamics and greenhouse gas (GHG) emissions in mineral and organic soils. The ECOSSE model has already been applied spatially to simulate land-use change impacts on soil C and GHG emissions. However, it has not been extensively evaluated under SRF. Eleven sites comprising 29 transitions in Britain, representing land-use change from nonwoodland land uses to SRF, were selected to evaluate the performance of ECOSSE in predicting soil C and soil C change in SRF plantations. The modelled C under SRF showed a strong correlation with the soil C measurements at both 0-30 cm ( R=0.93) and 0-100 cm soil depth ( R=0.82). As for the SRF plots, the soil C at the reference sites have been accurately simulated by the model. The extremely high correlation for the reference fields ( R ≥0.99) shows a good performance of the model spin-up. The statistical analysis of the model performance to simulate soil C and soil C changes after land-use change to SRF highlighted the absence of significant error between modelled and measured values as well as the absence of significant bias in the model. Overall, this evaluation reinforces previous studies on the ability of ECOSSE to simulate soil C and emphasize its accuracy to simulate soil C under SRF plantations.
  • Authors:
    • Biscaia, R. C. M.
    • Araújo, A. G.
    • Merten, G. H.
    • Barbosa, G. M. C.
    • Conte, O.
  • Source: Article
  • Volume: 152
  • Year: 2015
  • Summary: No-till is widely used to control soil erosion in agricultural areas in Brazil and is currently practiced on about 30. Mha. However, studies have shown that no-till is not as efficient in controlling surface runoff losses as it is in reducing soil loss. The objective of this study is to evaluate soil and surface runoff losses on small and large plots with differing slope lengths, cropping sequences and tillage systems in southern Brazil. Surface runoff and soil losses under natural rainfall erosion plots (3.5. ×. 11. m, 3.5. ×. 22. m, 50. ×. 100. m, and 100. ×. 100. m) were evaluated in two experiments in a well-drained Oxisol (>60% clay) with 9% and 7% slopes, respectively. The experiment extended over 14 years comparing 4 different soil management systems: (a) bare soil plots with slope length 22. m; (b) bare soil plots with slope length 11. m; (c) sequence of wheat (Triticum aestivum)/soybean [. Glycine max (L.) Merr] with disk plow. +. lighter off-set disk-harrow (DP+LD); and (d) sequence of wheat/soybean under no-till (NT). In another experiment using large field plots, three soil tillage regimens (DP. +. LD; heavy off-set disk-harrow. +. lighter off-set disk-harrow (HD. +. LD), and NT) were compared over the course of a 5-yr. crop sequence of black oats (Avena estrigosa)/soybean-black oats/corn (Zea mays L.)-wheat/soybean- black oats/soybean -blue lupine (Lupinus angustifolium)/corn. Results for both experiments show that, when compared with conventional soil tillage (DP. +. LD or HD. +. LD), soil losses for NT were >. 70% lower. However, the benefit of reduced surface runoff losses was less evident, suggesting the need to implement additional practices to control surface runoff to avoid transport of pollutants to waterways. © 2015 Elsevier B.V.
  • Authors:
    • Rezaei Rashti,M.
    • Wang,W.
    • Moody,P.
    • Chen,C.
    • Ghadiri,H.
  • Source: Atmospheric Environment
  • Volume: 112
  • Year: 2015
  • Summary: The emission of nitrous oxide (N2O) from vegetable fields contributes to the global greenhouse gases budget. However, reliable estimation of N2O emissions from vegetable production in the word has been lack. Vegetable cropping systems are characterised with high N application rates, irrigation, intensive production and multiple planting-harvest cycles during the year. Improved understanding of the key factors controlling N2O production is critical for developing effective mitigation strategies for vegetable cropping systems under different climate, soil type and management practices. Based on a comprehensive literature review and data analysis, we estimated the global N2O emission from vegetable production using seasonal fertiliser-induced emission factors (EFs) and examined the relationship of the seasonal emissions and EFs to possible controlling factors. The global average seasonal EF for vegetable fields is around 0.94% of applied N fertiliser, which is very similar to the Intergovernmental Panel on Climate Change (IPCC) annual emission factor of 1.0% for all cropping systems. The total N2O emission from global vegetable production is estimated to be 9.5×107kgN2O-N yr-1, accounting for 9.0% of the total N2O emissions from synthetic fertilisers. Stepwise multiple regression analysis on the relationships of soil properties, climatic factors and N application rates to seasonal N2O emissions and N2O EFs showed that N fertiliser application rate is the main regulator of seasonal N2O emission from vegetable fields but the seasonal EFs are negatively related to soil organic carbon (SOC) content. In fields receiving =250kgha-1N fertiliser, 67% (n=23, P=0.01) of the variation in seasonal emissions can be explained by the combined effects of N application rate, mean water-filled pore space (WFPS) and air temperature, while 59% (n=23, P=0.01) of the variation in seasonal EFs relates to temperature, mean WFPS and soil pH. The result also shows that in vegetable fields with mean seasonal air temperature higher than 14°C, increases in SOC decrease the seasonal EF and total N2O emissions from fertiliser N. © 2015 Elsevier Ltd.
  • Authors:
    • Daigh,A. L.
    • Sauer,T.
    • Xiao,X. H.
    • Horton,R.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 3
  • Year: 2015
  • Summary: Models of instantaneous soil-surface CO 2 efflux (SCE ins) are critical for understanding the potential drivers of soil C loss. Several simple SCE ins models have been reported in the literature. Our objective was to compare and validate selected soil temperature ( Ts)- and water content (theta v)-based equations for modeling SCE ins among a variety of cropping systems and land management practices. Soil-surface CO 2 effluxes were measured and modeled for grain-harvested corn ( Zea mays L.)-soybean [ Glycine max (L.) Merr.] rotations, grain- and stover-harvested continuous corn systems with and without a cover crop, and reconstructed prairies with and without N fertilization on soils with subsurface drainage. Soil-surface CO 2 effluxes, Ts, and theta v were measured from 2008 to 2011. Models calibrated with weekly measured SCE ins, Ts, and theta v throughout the growing season produced lower root mean squared error (RMSE) than models calibrated with several weeks of hourly measured data. Model selection significantly affected SCE ins estimations, with models that use only Ts parameters having lower RMSE than models that use both Ts and theta v. However, the model that produced the lowest RMSE during validation estimated growing-season SCE that did not significantly differ from numerical integration of weekly measured SCE ins. All models had similar residual errors with autocorrelated trends at monthly, weekly, and hourly scales. Autoregressive moving average functions were able to precisely describe the temporal errors. To accurately model SCE ins and scale across time, improvement of temporal errors in Ts- and theta v-based SCE ins models is needed to obtain accurate and precise closure of C balances for managed and natural ecosystems.
  • Authors:
    • Migliorati,M. de A.
    • Bell,M.
    • Grace,P. R.
    • Scheer,C.
    • Rowlings,D. W.
    • Liu Shen
  • Source: Agriculture, Ecosystems and Environment
  • Volume: 204
  • Issue: 1
  • Year: 2015
  • Summary: Alternative sources of N are required to bolster subtropical cereal production without increasing N 2O emissions from these agro-ecosystems. The reintroduction of legumes in cereal cropping systems is a possible strategy to reduce synthetic N inputs but elevated N 2O losses have sometimes been observed after the incorporation of legume residues. However, the magnitude of these losses is highly dependent on local conditions and very little data are available for subtropical regions. The aim of this study was to assess whether, under subtropical conditions, the N mineralised from legume residues can substantially decrease the synthetic N input required by the subsequent cereal crop and reduce overall N 2O emissions during the cereal cropping phase. Using a fully automated measuring system, N 2O emissions were monitored in a cereal crop (sorghum) following a legume pasture and compared to the same crop in rotation with a grass pasture. Each crop rotation included a nil and a fertilised treatment to assess the N availability of the residues. The incorporation of legumes provided enough readily available N to effectively support crop development but the low labile C left by these residues is likely to have limited denitrification and therefore N 2O emissions. As a result, N 2O emissions intensities (kg N 2O-N yield -1 ha -1) were considerably lower in the legume histories than in the grass. Overall, these findings indicate that the C supplied by the crop residue can be more important than the soil NO 3- content in stimulating denitrification and that introducing a legume pasture in a subtropical cereal cropping system is a sustainable practice from both environmental and agronomic perspectives.
  • Authors:
    • Niero,Monia
    • Ingvordsen,Cathrine H.
    • Peltonen-Sainio,Pirjo
    • Jalli,Marja
    • Lyngkjaer,Michael F.
    • Hauschild,Michael Z.
    • Jorgensen,Rikke B.
  • Source: Agricultural Systems
  • Volume: 136
  • Year: 2015
  • Summary: The paper has two main objectives: (i) to assess the eco-efficiency of spring barley cultivation for malting in Denmark in a future changed climate (700 ppm [CO2] and +5 degrees C) through Life Cycle Assessment (LCA) and (ii) to compare alternative future cultivation scenarios, both excluding and including earlier sowing and cultivar selection as measures of adaptation to a changed climate. A baseline scenario describing the current spring barley cultivation in Denmark was defined, and the expected main deviations were identified (differences in pesticide treatment index, modifications in nitrate leaching and change in crop yield). The main input data originate from experiments, where spring barley cultivars were cultivated in a climate phytotron under controlled and manipulated treatments. Effects of changed climate on both crop productivity and crop quality were represented, as well as impacts of predicted extreme events, simulated through a long heat-wave. LCA results showed that the changed climatic conditions will likely increase the negative impacts on the environment from Danish spring barley cultivation, since all environmental impact categories experienced increased impact for all investigated scenarios, except under the very optimistic assumption that the pace of yield improvement by breeding in the future will be the same as it was in the last decades. The main driver of the increased environmental impact was identified as the reduction in crop yield. Therefore, potential adaptation strategies should mainly focus on maintaining or improving crop productivity. The LCA also showed that selection of proper cultivars for future climate conditions including the challenge from extreme events is one of the most effective ways to reduce future environmental impacts of spring barley. Finally, if yield measurements are based on relative protein content, the negative effects of the future climate seem to be reduced. (C) 2015 Elsevier Ltd. All rights reserved.
  • Authors:
    • Smith,E. G.
    • Janzen,H. H.
    • Larney,F. J.
  • Source: Canadian Journal of Soil Science
  • Volume: 95
  • Issue: 2
  • Year: 2015
  • Summary: Long-term cropping system studies offer insights into soil management effects on agricultural sustainability. In 1995, a 6-yr bioassay study was superimposed on a long-term crop rotation study established in 1951 at Lethbridge, Alberta, to determine the impact of past cropping systems on soil quality, crop productivity, grain quality, and the relationship of yield productivity to soil quality. All plots from 13 long-term crop rotations were seeded to wheat ( Triticum aestivum L.) in a strip plot design [control, nitrogen (N) fertilizer]. Prior to seeding, soils were sampled to determine soil chemical properties. Total wheat production for the last 4 yr of the study was used as the measure of productivity. The 1995 soil analysis indicated crop rotations with less frequent fallow and with N input had higher soil quality, as indicated by soil organic carbon (SOC) and light fraction carbon (LF-C) and N (LF-N). SOC had a positive relationship to total wheat yield, but was largely masked by the application of N in this bioassay study. Frequent fallow in the previous crop rotation lowered productivity. The concentration of LF-C had a negative relationship, whereas LF-N had a positive relationship to total wheat yield, with and without N fertilization in this bioassay study. Grain N concentration was higher with applied N and when the long-term rotation included the addition of N by fertilizer, livestock manure, annual legume green manure or legume hay. This study determined that long-term imposition of management practices have lasting effects on soil quality and crop productivity.
  • Authors:
    • Zuber,S. M.
    • Behnke,G. D.
    • Nafziger,E. D.
    • Villamil,M. B.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 3
  • Year: 2015
  • Summary: Recent increases in corn ( Zea mays L.) production in the U.S. Corn Belt have necessitated the conversion of rotations to continuous corn, and an increase in the frequency of tillage. The objective of this study was to assess the effect of rotation and tillage on soil physical and chemical properties in soils typical of Illinois. Sequences of continuous corn (CCC), 2-yr corn-soybean [ Glycine max (L.) Merr.] (CS) rotation, 3-yr corn-soybean-wheat ( Triticum aestivum L.) (CSW) rotation, and continuous soybean (SSS) were split into conventional tillage (CT) and no-till (NT) subplots at two Illinois sites. After 15 yr, bulk density (BD) under NT was 2.4% greater than under CT. Water aggregate stability (WAS) was 0.84 kg kg -1 under NT compared to 0.81 kg kg -1 under CT. Similarly, soil organic carbon (SOC) and total nitrogen (TN) were greater under NT than under CT with SOC values for 0 to 60 cm of 96.0 and 91.0 Mg ha -1 and TN values of 8.87 and 8.40 Mg ha -1 for NT and CT, respectively. Rotations affected WAS, TN, and K levels with WAS being greatest for the CSW rotation at 0.87 kg kg -1, decreasing with more soybean years (CS, 0.82 kg kg -1 and SSS, 0.79 kg kg -1). A similar pattern was detected for TN and exchangeable K. Results indicated that while the use of NT improved soil quality, long-term implementation of continuous corn had similar soil quality parameters to those found under a corn-soybean rotation.
  • Authors:
    • Liu ShuWei
    • Zhao Chun
    • Zhang YaoJun
    • Hu ZhiQiang
    • Wang Cong
    • Zong YaJie
    • Zhang Ling
    • Zou JianWen
  • Source: GCB Bioenergy
  • Volume: 7
  • Issue: 4
  • Year: 2015
  • Summary: A full accounting of net greenhouse gas balance (NGHGB) and greenhouse gas intensity (GHGI) was examined in an annual coastal reclaimed saline Jerusalem artichoke-fallow cropping system under various soil practices including soil tillage, soil ameliorant, and crop residue amendments. Seasonal fluxes of soil carbon dioxide (CO 2), methane (CH 4), and nitrous oxide (N 2O) were measured using static chamber method, and the net ecosystem exchange of CO 2 (NEE) was determined by the difference between soil heterotrophic respiration ( RH) and net primary production (NPP). Relative to no-tillage, rotary tillage significantly decreased the NPP of Jerusalem artichoke while it had no significant effects on the annual RH. Rotary tillage increased CH 4 emissions, while seasonal or annual soil N 2O emissions did not statistically differ between the two tillage treatments. Compared with the control plots, soil ameliorant or straw amendment enhanced RH, soil CH 4, and N 2O emissions under the both tillage regimes. Annual NGHGB was negative for all the field treatments, as a consequence of net ecosystem CO 2 sequestration exceeding the CO 2-equivalents released as CH 4 and N 2O emissions, which indicates that Jerusalem artichoke-fallow cropping system served as a net sink of GHGs. The annual net NGHGB and GHGI were estimated to be 11-21% and 4-8% lower in the NT than in RT cropping systems, respectively. Soil ameliorant and straw amendments greatly increased NPP and thus significantly decreased the negative annual net NGHGB. Overall, higher NPP but lower climatic impacts of coastal saline bioenergy production would be simultaneously achieved by Jerusalem artichoke cultivation under no-tillage with improved saline soil conditions in southeast China.
  • Authors:
    • Möller,K.
  • Source: Agronomy for Sustainable Development
  • Volume: 35
  • Issue: 3
  • Year: 2015
  • Summary: Sustainability in agriculture means the inclusion of several aspects, as sustainable agriculture systems must not compromise not only their ability to satisfy future needs by undermining soil fertility and the natural resource base but also sustainable agriculture has had to address a range of other issues including energy use, efficient use, and recycling of nutrients, the effects on adjacent ecosystems including the effects on water bodies and climate change. Organic manures are an important factor to keep the soil fertility level of soils. However, their management is often related to large emissions. In this context, anaerobic digestion is—similarly to composting—a treatment option for stabilization of biogenic wastes leading to a residual product called digestates, enabling the sanitation and the recycling and use as fertilizer. It is also a means to obtain energy from wastes as well as from dedicated energy crops. Therefore, anaerobic digestion potentially addresses several aspects of agricultural sustainability. This review discusses the current state of knowledge on the effects of anaerobic digestion on organic compounds in digestates and the most important processes influencing N emissions in the field, as well as the possible long-term effects on soil microbial biomass and soil fertility. The main findings are that (1) the direct effects of anaerobic digestion on long-term sustainability in terms of soil fertility and environmental impact at the field level are of minor relevance. (2) The most relevant effects of anaerobic digestion on soil fertility as well as on N emissions will be expected from indirect effects related to cropping system changes such as changes in crop rotation, crop acreage, cover cropping, and total amounts of organic manures including digestates. Furthermore, (3) the remaining organic fraction after anaerobic digestion is much more recalcitrant than the input feedstocks leading to a stabilization of the organic matter and a lower organic matter degradation rate after field application, enabling a similar reproduction of the soil organic matter as obtained by direct application of the feedstock or by composting of the feedstock. (4) Regarding emissions, the main direct effect of anaerobic digestion on a farm level is the influence on gaseous emissions during manure or digestate treatment and handling, whereas the direct effects of anaerobic digestion on a field level on emissions (NH3− and N2O− emissions, NO3- leaching) are negligible or at least ambiguous. (5) The main direct effects of anaerobic digestion on the field level are short-term effects on soil microbial activity and changes in the soil microbial community. Therefore, in terms of the effects on agricultural sustainability, potential cropping system-based changes induced by introduction of biogas plants are probably much more relevant for the overall performance and sustainability of the cropping system than the direct effects triggered by application of digestates in comparison to the undigested feedstocks. Furthermore, to get the full potential advances from implementation of biogas plants in terms of improvement of the nutrient use efficiency and reduction of greenhouse gas emissions, there is the need to introduce more sophisticated techniques to avoid counteracting effects by pollution swapping, e.g., by gas-tight closure of the digestate stores and direct soil incorporation of the field-applied digestates. © 2015, INRA and Springer-Verlag France.