• Authors:
    • Bernoux, M.
    • Bockel, L.
    • Tinlot, M.
    • Lipper, L.
    • Medeiros, K.
    • Benez, M. C.
    • Hissa, H.
    • Branca, G.
  • Source: Land Use Policy
  • Volume: 30
  • Issue: 1
  • Year: 2013
  • Summary: This paper presents the results of the EX-Ante Carbon-balance Tool (EX-ACT) application on two rural development projects in Brazil. The analysis provides an estimate of project impact on GHG emissions and C sequestration indicating net mitigation potential: results show that the Santa Catarina Rural Competitiveness Project has the potential to mitigate 12.2 Mt CO(2)e and the Rio de Janeiro Sustainable Rural Development Project 0.85 Mt CO(2)e. Both projects are successful at promoting activities aimed at reducing rural poverty and also contribute to climate change mitigation, demonstrating the potential importance of sustainable agriculture (improved cropland and grassland management, expansion of agro-forestry systems and protection of forested areas) in delivering environmental services. EX-ACT has also been used as a tool to guide project developers in refining components and activities to increase project environmental benefits. Cost-benefit analysis shows that while both projects generate environmental benefits associated with climate change mitigation, the Santa Catarina Rural Competitiveness Project has significantly higher potential due to the size of the project area and the nature of activities, thus a higher likelihood of potential co-financing from climate finance sources.
  • Authors:
    • Heinemann, A. B.
    • Moreira, J. A. A.
    • Silveira, P. M. da
    • Machado, P. L. O. de A.
    • Costa, A. R. da
    • Leal, W. G. de O.
    • Madari, B. E.
    • Carvalho, M. T. de M.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 48
  • Issue: 5
  • Year: 2013
  • Summary: The objective of this work was to measure the fluxes of N2O‑N and NH3‑N throughout the growing season of irrigated common‑bean (Phaseolus vulgaris), as affected by mulching and mineral fertilization. Fluxes of N2O‑N and NH3‑N were evaluated in areas with or without Congo signal grass mulching (Urochloa ruziziensis) or mineral fertilization. Fluxes of N were also measured in a native Cerrado area, which served as reference. Total N2O‑N and NH3‑N emissions were positively related to the increasing concentrations of moisture, ammonium, and nitrate in the crop system, within 0.5 m soil depth. Carbon content in the substrate and microbial biomass within 0.1 m soil depth were favoured by Congo signal grass and related to higher emissions of N2O‑N, regardless of N fertilization. Emission factors (N losses from the applied mineral nitrogen) for N2O‑N (0.01-0.02%) and NH3‑N (0.3-0.6%) were lower than the default value recognized by the Intergovernmental Panel on Climate Change. Mulch of Congo signal grass benefits N2O‑N emission regardless of N fertilization.
  • Authors:
    • Castanheira, E. G.
    • Freire, F.
  • Source: Journal of Cleaner Production
  • Volume: 54
  • Year: 2013
  • Summary: The increase in soybean production as a source of protein and oil is being stimulated by the growing demand for livestock feed, food and numerous other applications. Significant greenhouse gas (GHG) emissions can result from land use change due to the expansion and cultivation of soybean. However, this is complex to assess and the results can vary widely. The main goal of this article is to investigate the life-cycle GHG balance for soybean produced in Latin America, assessing the implications of direct land use change emissions and different cultivation systems. A life-cycle model, including inventories for soybean produced in three different climate regions, was developed, addressing land use change, cultivation and transport to Europe. A comprehensive evaluation of alternative land use change scenarios (conversion of tropical forest, forest plantations, perennial crop plantations, savannah and grasslands), cultivation (tillage, reduced tillage and no-tillage) and soybean transportation systems was undertaken. The main results show the importance of land use change in soybean GHG emissions, but significant differences were observed for the alternative scenarios, namely 0.1-17.8 kg CO(2)eq kg(-1) soybean. The original land choice is a critical issue in ensuring the lowest soybean GHG balance and degraded grassland should preferably be used for soybean cultivation. The highest GHG emissions were calculated for tropical moist regions when rainforest is converted into soybean plantations (tillage system). When land use change is not considered, the GHG intensity varies from 0.3 to 0.6 kg CO(2)eq kg(-1) soybean. It was calculated that all tillage systems have higher GHG emissions than the corresponding no-tillage and reduced tillage systems. The results also show that N2O emissions play a major role in the GHG emissions from cultivation, although N2O emission calculations are very sensitive to the parameters and emission factors adopted.
  • Authors:
    • Spargo, J. T.
    • Teasdale, J. R.
    • Mirsky, S. B.
    • Cavigelli, M. A.
    • Doran, J.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 28
  • Issue: 2
  • Year: 2013
  • Summary: Organic grain cropping systems can enhance a number of ecosystem services compared with conventional tilled (CT) systems. Recent results from a limited number of long-term agricultural research (LTAR) studies suggest that organic grain cropping systems can also increase several ecosystem services relative to conventional no-till (NT) cropping systems: soil C sequestration and soil N fertility (N mineralization potential) can be greater while global warming potential (GWP) can be lower in organic systems that use animal manures and cover crops compared with conventional NT systems. However, soil erosion from organic systems and nitrous oxide (N2O, a greenhouse gas) emissions from manure-based organic systems appear to be greater than from conventional NT systems, though data are limited. Also, crop yields, on average, continue to be lower and labor requirements greater in organic than in both tilled and NT conventional systems. Ecosystem services provided by organic systems may be improved by expanding crop rotations to include greater crop phenological diversity, improving nutrient management, and reducing tillage intensity and frequency. More diverse crop rotations, especially those that include perennial forages, can reduce weed pressure, economic risk, soil erosion, N2O emissions, animal manure inputs, and soil P loading, while increasing grain yield and soil fertility. Side-dressing animal manures in organic systems may increase corn nitrogen use efficiency and also minimize animal manure inputs. Management practices that reduce tillage frequency and intensity in organic systems are being developed to reduce soil erosion and labor and energy needs. On-going research promises to further augment ecosystem services provided by organic grain cropping systems.
  • Authors:
    • Zhang, Y.
    • Wu, L.
    • Wang, H.
    • Liu, L.
    • Huang, L.
    • Niu, Y.
    • Chai, R.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 96
  • Issue: 1
  • Year: 2013
  • Summary: Proper management of synthetic nitrogen (N) fertilizer can reduce direct N2O emission from soil and indirect CO2 emission from production and transportation of synthetic N. In the late 1990s, the average application rates of synthetic N were 212, 207 and 207 kg ha(-1), respectively, for rice, wheat, and maize in China's croplands. But research suggests that the optimal synthetic N application rates for the main grain crops in China should be in the range of 110-150 kg ha(-1). Excessive application of synthetic N has undoubtedly resulted in massive emission of greenhouse gases. Therefore, optimizing N application rates for grain crops in China has a great potential for mitigating the emission of greenhouse gases. Nevertheless, this mitigation potential (MP) has not yet been well quantified. This study aimed at estimating the MP of N2O and CO2 emissions associated with synthetic N production and transportation in China based on the provincial level statistical data. Our research indicates that the total consumption of synthetic N on grain crops in China can be reduced by 5.0-8.4 Tg yr(-1) (28-47 % of the total consumption) if the synthetic N application rate is controlled at 110-150 kg ha(-1). The estimated total MP of greenhouse gases, including direct N2O emission from croplands and indirect CO2 emission from production and transportation of synthetic N, ranges from 41.7 to 70.1 Tg CO2_eq. yr(-1). It was concluded that reducing synthetic N application rate for grain crops in China to a reasonable level of 110-150 kg ha(-1) can greatly reduce the emission of greenhouse gases, especially in the major grain-crop production provinces such as Shandong, Henan, Jiangsu, Hebei, Anhui and Liaoning.
  • Authors:
    • Pan, G.
    • Smith, P.
    • Nayak, D.
    • Zheng, J.
    • Cheng, K.
  • Source: Soil Use and Management
  • Volume: 29
  • Issue: 4
  • Year: 2013
  • Summary: To assess the topsoil carbon sequestration potential (CSP) of China's cropland, two different estimates were made: (i) a biophysical potential (BP) using a saturation limit approach based on soil organic carbon (SOC) accumulation dynamics and a storage restoration approach from the cultivation-induced SOC loss, and (ii) a technically attainable potential (TAP) with a scenario estimation approach using SOC increases under best management practices (BMPs) in agriculture. Thus, the BP is projected to be the gap in recent SOC storage to either the saturation capacity or to the SOC storage of uncultivated soil, while the TAP is the overall increase over the current SOC storage that could be achieved with the extension of BMPs. The recent mean SOC density of China's cropland was estimated to be 36.44t/ha, with a BP estimate of 2.21 Pg C by a saturation approach and 2.95 Pg C by the storage restoration method. An overall TAP of 0.62 Pg C and 0.98 Pg C was predicted for conservation tillage plus straw return and recommended fertilizer applications, respectively. This TAP is comparable to 40-60% of total CO2 emissions from Chinese energy production in 2007. Therefore, carbon sequestration in China's cropland is recommended for enhancing China's mitigation capacity for climate change. However, priority should be given to the vast dry cropland areas of China, as the CSP of China is based predominantly on the dry cropland.
  • Authors:
    • Saad, A. A.
    • Das, S.
    • Sharma, A. R.
    • Bhattacharyya, R.
    • Das, T. K.
    • Pathak, H.
  • Source: European Journal of Agronomy
  • Volume: 51
  • Year: 2013
  • Summary: Sequestration of C in arable soils has been considered as a potential mechanism to mitigate the elevated levels of atmospheric greenhouse gases. We evaluated impacts of conservation agriculture on change in total soil organic C (SOC) and relationship between C addition and storage in a sandy loam soil of the Indo-Gangetic Plains. Cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) crops were grown during the first three years (2008-2011) and in the last year, maize (Zea mays L), wheat and green gram (Vigna radiate L.) were cultivated. Results indicate the plots under zero tillage with bed planting (ZT-B) and zero tillage with flat planting (ZT-F) had nearly 28 and 26% higher total SOC stock compared with conventional tillage and bed planting (CT-B) (similar to 5.5 Mg ha(-1)) in the 0-5 cm soil layer. Plots under ZT-B and ZT-F contained higher total SOC stocks in the 0-5 and 5-15 cm soil layers than CT-B plots. Although there were significant variations in total SOC stocks in the surface layers, SOC stocks were similar under all treatments in the 0-30 cm soil layer. Residue management had no impact on SOC stocks in all layers, despite plots under cotton/maize + wheat residue (C/M+W RES) contained similar to 13% higher total SOC concentration than no residue treated plots (N RES; similar to 7.6 g kg(-1)) in the 0-5 cm layer. Hence, tillage and residue management interaction effects were not significant. Although CT-B and ZT-F had similar maize aboveground biomass yields, CT-F treated plots yielded 16% less maize biomass than CT-B plots. However, both wheat and green gram (2012) yields were not affected by tillage. Plots under C/M + W RES had similar to 17, 13, 13 and 32% higher mean cotton, maize, wheat and green gram aboveground biomass yields than N RES plots, yielding similar to 16% higher estimated root (and rhizodeposition) C input in the 0-30 cm soil layer than N RES plots. About 9.3% of the gross C input contributed towards the increase in SOC content under the residue treated plots. However, similar to 7.6 and 10.2% of the gross C input contributed towards the increase in SOC content under CT and if, respectively. Thus, both ZT and partial or full residue retention is recommended for higher soil C retention and sustained crop productivity. (c) Elsevier B.V. All rights reserved.
  • Authors:
    • Feigl, B. J.
    • Cerri, C. C.
    • Pellegrino Cerri, C. E.
    • Nunes Carvalho, J. L.
    • de Oliveira, B. G.
  • Source: Geoderma
  • Volume: 200
  • Issue: June
  • Year: 2013
  • Summary: Sugarcane ethanol is the main liquid biofuel used in Brazil as a substitute for fossil fuels for the mitigation of greenhouse gas (GHG) emissions. However, ethanol production also produces GHG emissions during the agricultural phase through the disposal of its residues. Vinasse, as the main residue from ethanol production, may contribute to GHG emission during its storage, transportation and application to soil as ferti-irrigation. The objective of this study was to quantify the fluxes of CO2, CH4 and N2O resulting from vinasse application in sugarcane fields under different straw managements and to determine the N2O emission factor derived from this practice. This study was performed at the Boa Vista Farm, in Sao Paulo State, Brazil. The application of 200 m(3) ha(-1) of vinasse tripled the CO2 emissions in areas with burnt or unburnt harvest systems. The consumption of CH4 was observed, supporting the hypothesis that this usually applied amount of vinasse to the soil does not necessarily result in CH4 emissions. The 46 kg of N contained in this dose of vinasse increased the release of N2O by the soil and resulted in emission factors of 0.68% and 0.44% for the burnt and unburnt areas, respectively. The fluxes of N2O and CH4, converted into CO2 eq, indicate that each m(3) ha(-1) of vinasse applied to the soil emits 0.491 and 0314 kg of CO2 eq. in the burnt and unburnt sugarcane areas, respectively. (C) 2013 Elsevier B.V. All rights reserved.
  • Authors:
    • Zeng, A.
    • Zhou, J.
    • Mao, X.
    • Dong, G.
  • Source: Ecological Economics
  • Volume: 91
  • Year: 2013
  • Summary: In recent decades, Chinese agriculture has moved towards higher-energy and higher carbon-input systems to increase food production in the country's limited area of croplands. To investigate the environmental impacts of this trend, this study aimed to develop an "Integrated Life Cycle Assessment and Environmental Input-Output Model" (LCA-EIO Model). Using the tri-scope carbon footprint (CF) accounting method, the agricultural carbon footprint of Zhejiang Province, China was calculated for the years from 1997 to 2007, and the categories and structure of carbon emissions sources were analyzed, including patterns of change. In addition, the carbon intensity of crop farming in Zhejiang Province was examined. While an overall reduction in cropland areas has resulted in a substantial decline in direct greenhouse gas emissions from agricultural production, the proportion of carbon emissions caused by energy and chemical consumption has increased dramatically, and this consumption has become the primary source of carbon emissions. A decomposition analysis also identified the key driving forces of energy-related CF dynamics, such as the machinery-labor substitution effect. The results of the decomposition analysis can support decision makers in understanding and promoting low-carbon output agriculture.
  • Authors:
    • Long, S. P.
    • Keogh, C.
    • Davis, S. C.
    • Anderson-Teixeira, K. J.
    • Duval, B. D.
    • Parton, W. J.
    • DeLucia, E. H.
  • Source: PLoS ONE
  • Volume: 8
  • Issue: 8
  • Year: 2013
  • Summary: Bioenergy related land use change would likely alter biogeochemical cycles and global greenhouse gas budgets. Energy cane (Saccharum officinarum L.) is a sugarcane variety and an emerging biofuel feedstock for cellulosic bio-ethanol production. It has potential for high yields and can be grown on marginal land, which minimizes competition with grain and vegetable production. The DayCent biogeochemical model was parameterized to infer potential yields of energy cane and how changing land from grazed pasture to energy cane would affect greenhouse gas (CO2, CH4 and N2O) fluxes and soil C pools. The model was used to simulate energy cane production on two soil types in central Florida, nutrient poor Spodosols and organic Histosols. Energy cane was productive on both soil types (yielding 46-76 Mg dry mass.ha(-1)). Yields were maintained through three annual cropping cycles on Histosols but declined with each harvest on Spodosols. Overall, converting pasture to energy cane created a sink for GHGs on Spodosols and reduced the size of the GHG source on Histosols. This change was driven on both soil types by eliminating CH4 emissions from cattle and by the large increase in C uptake by greater biomass production in energy cane relative to pasture. However, the change from pasture to energy cane caused Histosols to lose 4493 g CO2 eq.m(-2) over 15 years of energy cane production. Cultivation of energy cane on former pasture on Spodosol soils in the southeast US has the potential for high biomass yield and the mitigation of GHG emissions.