• Authors:
    • Dequiedt, B.
    • Moran, D.
  • Source: Ecological Economics
  • Volume: 110
  • Year: 2015
  • Summary: This paper considers the cost of greenhouse gas mitigation potential of legume crops in French arable systems. We construct marginal abatement cost curves to represent this mitigation or abatement potential for each department of France and provide a spatial representation of its extent. Despite some uncertainty, the measure appears to offer a significant low cost mitigation potential. We estimate that the measure could abate half of the emission reduction sought by a national plan for the reduction of chemical fertilizer emissions by 2020. This would be achieved at a loss of farmland profit of 1.2%. Considering the geographical heterogeneity of cost, we suggest that a policy implementing carbon pricing in agriculture would be more efficient than a uniform regulatory requirement for including the crop in arable systems.
  • Authors:
    • Zhang, Q.
    • Hu, C.
    • Ren, T.
    • Du, Z.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 146
  • Issue: Pt. A
  • Year: 2015
  • Summary: Physical protection by soil aggregates is critical for building soil organic carbon (SOC) stock. The objective of this study was to identify SOC sequestrated in the microaggregate holding within macroaggregte (mM) fraction after shifting tillage systems in the North China Plain. Soil samples from 0-5. cm layer of a 6-yr field experiment (MP. -. R, moldboard plow without residue; MP. +. R, moldboard plow with residue; RT, rotary tillage with residue; NT, no-till with residue) were collected and separated into different water-stable aggregates. The macroaggregate (250-2000. µm) was further isolated into intra-aggregate particulate organic matter (iPOM) fractions by density flotation, dispersion and sieving. The results showed that the SOC concentration of fine iPOM (250f, 53-250. µm) was increased by 23% in RT and 39% in NT compared with MP. +. R, whereas the difference in the coarse iPOM (250c, >250. µm) was not observed. The ratio of 250f-250c (i.e., 250f/250c) followed the order of NT (2.12). ˜. RT (1.94). >. MP. +. R (1.50). ˜. MP. -. R (1.47), indicating the alternative tillage systems decreased the turnover rates of macroaggregates. Adoption of NT and RT improved the mM formation by 36% and 23% and mM associated C concentration by 38% and 31% as relative to MP. +. R system. Additionally, the soil C concentration and storage of the iPOM and silt plus clay fractions located within the microaggregate were higher under NT and RT than that of MP. +. R and MP. -. R systems. Thus applying NT and RT improved mM formation and soil C sequestered inside this fraction. We concluded that adoption of NT and RT enhanced SOC sequestration in the microaggregates of surface soil of the intensive agroecosystem of North China.
  • Authors:
    • Jurasinski, G.
    • Buczko, U.
    • Fiedler, S. R.
    • Glatzel, S.
  • Source: Soil and Tillage Research
  • Volume: 150
  • Year: 2015
  • Summary: Temperature-driven models of soil respiration (SR) are crucial for estimating C-balances of arable soils. However, model construction may be severely influenced by tillage operations. The impact of tillage on the temperature dependence of SR was studied to reveal the temporal patterns of model quality of temperature-driven SR-models. To obtain SR, CO2 fluxes were measured with a dynamic chamber technique in treatments of an energy crop rotation amended with biogas residues (BR) and mineral fertiliser (MF). Measurements were performed with short intervals during the first three days after tillage operations, then with extending intervals between measurements up to 35 days after tillage. Additionally, soil concentrations of hot-water extractable organic carbon (HWC) were determined before and during the experiment. Overall, in all treatments individual CO2 fluxes were affected by the extent of soil disturbance and fertiliser treatment. The highest tillage-induced fluxes where observed after disking in MF treatment. Tillage also induced an immediate increase of HWC, indicating additional labile C and a fast response of microbial activity. However, the change of HWC lasted only one day and approximated the pre-tillage values within a week. Even though BR soil had a higher HWC content, the increased C mineralisation in one repetition of MF suggests that buried plant residues might have a higher influence on SR after tillage than the type of fertiliser. Directly after soil disturbance by tillage it was impossible to construct temperature-driven models for SR in all treatments. Assuming that the coefficient of determination is appropriate with R2≥0.5 and the model quality is good with NRMSE≤0.15, the qualities of the models increased continuously with time, but were unsatisfying for at least two weeks. During this time, SR showed a high sensitivity to changing environmental influences like precipitation and soil moisture or available C for microbial turnover, rather than temperature. The treatment BR showed a less sensitive pattern, which might be attributed to an altered soil structure and microbial activity of soil after long-term application of an organic fertiliser like BR. Therefore, temperature-driven models for the prediction of soil derived CO2 emissions should be applied carefully for the days and weeks after tillage and verification by measurements in shorter intervals is advisable.
  • Authors:
    • Clevers, J. G. P. W.
    • Verburg, P. H.
    • Herold, M.
    • Fuchs, R.
    • Eberle, J.
  • Source: GLOBAL CHANGE BIOLOGY
  • Volume: 21
  • Issue: 1
  • Year: 2015
  • Summary: Historic land-cover/use change is important for studies on climate change, soil carbon, and biodiversity assessments. Available reconstructions focus on the net area difference between two time steps (net changes) instead of accounting for all area gains and losses (gross changes). This leads to a serious underestimation of land-cover/use dynamics with impacts on the biogeochemical and environmental assessments based on these reconstructions. In this study, we quantified to what extent land-cover/use reconstructions underestimate land-cover/use changes in Europe for the 1900-2010 period by accounting for net changes only. We empirically analyzed available historic land-change data, quantified their uncertainty, corrected for spatial-temporal effects and identified underlying processes causing differences between gross and net changes. Gross changes varied for different land classes (largest for forest and grassland) and led to two to four times the amount of net changes. We applied the empirical results of gross change quantities in a spatially explicit reconstruction of historic land change to reconstruct gross changes for the EU27 plus Switzerland at 1 km spatial resolution between 1950 and 2010. In addition, the reconstruction was extended back to 1900 to explore the effects of accounting for gross changes on longer time scales. We created a land-change reconstruction that only accounted for net changes for comparison. Our two model outputs were compared with five commonly used global reconstructions for the same period and area. In our reconstruction, gross changes led in total to a 56% area change (ca. 0.5% yr -1) between 1900 and 2010 and cover twice the area of net changes. All global reconstructions used for comparison estimated fewer changes than our gross change reconstruction. Main land-change processes were cropland/grassland dynamics and afforestation, and also deforestation and urbanization.
  • Authors:
    • Kohlheb, N.
    • Fuchsz, M.
  • Source: JOURNAL OF CLEANER PRODUCTION
  • Volume: 86
  • Year: 2015
  • Summary: The environmental effects of anaerobic digestion (AD) plants have not, to date, been thoroughly analysed. The technology of biogas production has developed enormously in the last 10 years, with equipment functioning at ever-improving efficiency. In the present study, we aimed to examine the environmental effects of biogas plants that operate with the same power production capacity, but use different raw materials during the full life cycle. In addition, the environmental effects that occur during the establishment of AD plants were defined and contrasted against emissions during the full life cycle. In life cycle analysis (LCA), the greenhouse gas (GHG) emission effect of biogas production was measured as kg CO2 eq/kWhe, the acidification potential as kg SO2 eq/kWhe, and the eutrophication potential as kg PO4 eq/kWhe. The calculations proved that an AD plant that processes only energy crops as raw materials can be regarded as a CO2 absorber (-188 g/kWhe). The CO2 emission of all three examined plants was below the average emission of electrical power currently produced in a conventional manner. The AD plant that processes low-energy-density agricultural wastes produced 7.7% of its full-life-cycle CO2 emissions during its construction phase, compared with a 0.9% ratio for the AD plant processing only energy crops. However, the manure-based AD plant contributed the most to the decline in environmental acidification.
  • Authors:
    • Berger, T.
    • Siebold, M.
    • Gil, J.
  • Source: AGRICULTURE ECOSYSTEMS & ENVIRONMENT
  • Volume: 199
  • Year: 2015
  • Summary: By combining crop, livestock and/or forestry activities in the same area, integrated systems (IS) can increase, organic matter content in the soil - which favors biomass production and allows for higher livestock stocking rates in pasturelands. The implementation of IS is therefore seen as a promising strategy for sustainable agricultural intensification in Brazil, particularly in Mato Grosso state (MT). However, despite the benefits associated with IS and incentives offered by the federal government to stimulate their dissemination, little is known about these systems or the challenges to implement them, and only a limited number of farmers have adopted IS so far. This paper presents a comprehensive assessment of all IS identified in Mato Grosso by 2012/13, which were mapped and described in terms of their main technical and non-technical features. These findings were combined with farm survey data set to provide a detailed account of the various technologies currently being disseminated, their individual diffusion levels and potential adoption constraints. Results generated through qualitative and quantitative research methods give an overview of IS' state of the art, reveal farmer perception of such technology and offer insights into the prospects for low-carbon agriculture in the region. The study's major findings are that IS are present in more than 40 of the 141 municipalities of MT, and the vast majority (89%) involve only crop and livestock. Farmers have adopted three different crop-livestock configurations, depending on their production strategy. Cultural aspects play a major role in farmer decisions to adopt IS, credit provision has not been relevant for IS adoption, and a broader dissemination of IS may occur as land transitions continue. (C) 2014 Elsevier B.V. All rights reserved.
  • Authors:
    • Marquez-Garcia, F.
    • Blanco-Roldan, G. L.
    • Veroz-Gonzalez, O.
    • Gonzalez-Sanchez, E. J.
    • Carbonell-Bojollo, R.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 146
  • Issue: Pt. B
  • Year: 2015
  • Summary: The interest in conservation agriculture in Spain is evidenced by practical and institutional aspects. The practical aspect is reflected by the area cultivated under this farming system, 1.28. Mha in perennial crops and 0.57. Mha in arable crops, both for 2013. The period under review was 2009-2013 for arable crops and 2006-2013 for perennial crops. In that period, figures increased 208% for no tillage in arable crops, and 54% for groundcovers in perennial crops. The institutional support is reflected by the financial funding given to conservation agriculture farming practices by some Spanish Regional Governments, primarily through Rural Development Programs, that reached over € 200 million in the 2000-2006 period. The origins of soil conservation practices date back to the 1930s and have evolved in parallel in America and Europe. This parallelism has led to the use of different terminology for similar practices that do not always fall within the scope of conservationist practices. Consistent with the literature, and based on the results of 6 meetings with 144 Spanish experts, this paper aimed at clarifying terms and practices applied under the conditions of Spain, but could be useful for other geographies. This article also proposes definitions to clearly describe the different concepts for experts, advisers, and also for policy makers to accurately allocate funds in the European financial framework 2014-2020.
  • Authors:
    • Corrêa, J. C.
    • Aita, C.
    • Cassol, P. C.
    • Nicoloso, R. D. S.
    • Grave, R. A.
    • Costa, M. D.
    • Fritz, D. D.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 146
  • Issue: Pt. B
  • Year: 2015
  • Summary: Agriculture can be either a source or sink of atmospheric CO2 depending on soil management. The application of swine slurry in conventional tilled soils could enhance soil CO2 emission depleting soil organic C stocks. However, the use of recalcitrant C-rich organic fertilizers in no-till soils can offset soil CO2 emission promoting soil C sequestration. This hypothesis was tested by evaluating short-term CO2-C emissions from a Rhodic Nitisol under contrasting soil disturbance levels (disturbed (DS) and undisturbed soil (US)) top-dressed with mineral or organic fertilizers (urea (UR), raw swine slurry (RS), anaerobically digested swine slurry (ADS), and composted swine slurry (CS)). Soil CO2 emission was evaluated for 64 days using static chambers where gas samples were collected and analysed by photoacoustic infrared spectroscopy. Soil water-filled pore space (WFPS), temperature and meteorological data were concomitantly registered and a first-order exponential decay model was used to assess the decomposition of organic fertilizers and CO2 emissions induced by soil disturbance. Soil CO2-C emission was correlated with soil temperature, while limiting soil aeration impaired CO2-C efflux when WFPS >0.6cm3cm-3. Disturbance increased soil CO2-C efflux (36.3±2.2kg CO2-Cha-1 day-1) in relation to US (33.3±1.6kg CO2-Cha-1 day-1). Extra labile C input through RS amendment induced an increased soil CO2-C efflux for a longer period (t1/2=16.9 and 9.6 days in DS and US treatments, respectively), resulting in higher CO2-C emissions than soil amended with other fertilizers. The recalcitrant C input by ADS and CS had limited effect on soil CO2-C emissions. CS presented a genuine potential for substantial soil organic C accumulation while offsetting increased CO2-C emissions in comparison to RS amended soils.
  • Authors:
    • Gutiérrez-Castorena, M. D. C.
    • Gutiérrez-Castorena, E. V.
    • Ortiz-Solorio, C. A.
  • Source: Soil and Tillage Research
  • Volume: 150
  • Year: 2015
  • Summary: In recent years, conservation tillage has been promoted as a method of increasing the quality of agricultural soils; however, in the Aridisols of northeastern Mexico, this type of tillage is not practical because of the formation of natural crusts. Conventional tillage systems that include different culture practices have been used for six decades to increase the yields. However, little is known of the changes to the soil properties and modifications to the moisture control section. Six agricultural plots representative of 78,000 ha in districts of the state of Tamaulipas, Mexico were studied based on their management: rainfed or irrigated, with or without the incorporation of crop residues and with or without plot drainage. The results show that three moisture regimes occur in the soils according to the irrigation intensity and plot drainage: aridic, ustic and udic. The aridic regime presents the greatest organic carbon stock (58Mgha-1), stability of aggregates in particles >2 mm in the arable layer and produces sorghum yields of up to 2.5tha-1. In the udic regime, because of plot drainage and the incorporation of crop residue and manure, there is high biological activity; in addition, stability of aggregates is along the whole profile, alkalinisation and redox processes occur, and short-cycle maize yields are up to 10tha-1. The different management practices for intense production modify the moisture regime but do not modify the organic carbon capture. The pedogenetic processes are related to the management intensity and cause the Aridisols to evolve into inceptisols in less than six decades of agricultural activity; however, only the redox processes are expressed in their classification despite a significant amount of calcitic features.
  • Authors:
    • Mukome, F. N. D.
    • Chaukura, N.
    • Gwenzi, W.
    • Machado, S.
    • Nyamasoka, B.
  • Source: Journal of Environmental Management
  • Volume: 150
  • Year: 2015
  • Summary: Sub-Saharan Africa (SSA) experiences soil degradation, food and livelihood insecurity, environmental pollution and lack of access to energy. Biochar has gained international research attention, but few studies have investigated the potential of biochar to address the challenges in SSA. This paper seeks to identify and evaluate generic potential opportunities and constraints associated with biochar application in sub-Saharan Africa using Zimbabwe as case study. Specific objectives were to; (1) identify and quantify feedstocks for biochar production; (2) review literature on the biochar properties, and evaluate its potential applications in agriculture, environmental remediation and energy provision, and (3) identify research gaps, risks and constraints associated with biochar technology. Biochar feedstocks in Zimbabwe were estimated to be 9.9Mtonyr-1, predominantly derived from manure (88%) and firewood (10%). This will yield 3.5, 1.7 and 3.1Mtonyr-1 of biochar, bio-oil and synthetic gas, respectively. Land application of the 3.5Mtonyr-1 of biochar (˜63% C) would sequester approximately 2.2Mtonyr-1 of soil carbon in Zimbabwe alone, while simultaneously minimizing the environmental and public health risks, and greenhouse gas emissions associated with solid organic wastes. Biochar potentially enhances soil and crop productivity through enhanced nutrient and soil moisture availability, amelioration of acidic soils and stimulation of microbial diversity and activity. Due to its excellent adsorption properties, biochar has potential applications in industrial and environmental applications including water and wastewater treatment, remediation and revegetation of contaminated soils and water. Biochar products have energy values comparable or higher than those of traditional biomass fuels; thereby making them ideal alternative sources of energy especially for poor households without access to electricity. Before the benefits of biochar can be realized in SSA, there is need to overcome multiple risks and constraints such as lack of finance, socio-economic constraints including negative perceptions and attitudes among both researchers and consumers, and environmental and public health risks. Therefore, there is need to conduct fundamental research to demonstrate the benefits of biochar applications, and develop policy framework and criteria for its production and subsequent adoption.