• Authors:
    • McCoy, T. D.
    • Guan, Q. F.
    • Mitchell, R. B.
    • Allen, C. R.
    • Uden, D. R.
  • Source: Journal of Soil and Water Conservation
  • Volume: 68
  • Issue: 5
  • Year: 2013
  • Authors:
    • Christie, P.
    • Gao, B.
    • Huang, T.
    • Ju, X.
  • Source: Biogeosciences
  • Volume: 10
  • Issue: 12
  • Year: 2013
  • Summary: The effects of nitrogen and straw management on global warming potential (GWP) and greenhouse gas intensity (GHGI) in a winter wheat-summer maize double-cropping system on the North China Plain were investigated. We measured nitrous oxide (N2O) emissions and studied net GWP (NGWP) and GHGI by calculating the net exchange of CO2 equivalent (CO2-eq) from greenhouse gas emissions, agricultural inputs and management practices, as well as changes in soil organic carbon (SOC), based on a long-term field experiment established in 2006. The field experiment includes six treatments with three fertilizer N levels (zero N (control), optimum and conventional N) and straw removal (i.e. N-0 N-opt and N-con) or return (i.e. SN0, SNopt and SNcon). Optimum N management (N-opt, SNopt) saved roughly half of the fertilizer N compared to conventional agricultural practice (N-con, SNcon), with no significant effect on grain yields. Annual mean N2O emissions reached 3.90 kg N2O-N ha(-1) in N-con and SNcon, and N2O emissions were reduced by 46.9% by optimizing N management of N-opt and SNopt. Straw return increased annual mean N2O emissions by 27.9 %. Annual SOC sequestration was 0.40-1.44Mg C ha(-1) yr(-1) in plots with N application and/or straw return. Compared to the conventional N treatments the optimum N treatments reduced NGWP by 51 %, comprising 25% from decreasing N2O emissions and 75% from reducing N fertilizer application rates. Straw return treatments reduced NGWP by 30% compared to no straw return because the GWP from increments of SOC offset the GWP from higher emissions of N2O, N fertilizer and fuel after straw return. The GHGI trends from the different nitrogen and straw management practices were similar to the NGWP. In conclusion, optimum N and straw return significantly reduced NGWP and GHGI and concomitantly achieved relatively high grain yields in this important winter wheat-summer maize double-cropping system.
  • Authors:
    • Zhang, X-C.
    • Zheng, Z-Q.
    • Lu, Z.-Y.
    • Lu, C.-Y.
    • Sivelli,A.
    • Li, H.-W.
    • Wang, Q-J.
    • He, J
    • Li, H.
  • Source: Soil Science
  • Volume: 178
  • Issue: 1
  • Year: 2013
  • Summary: Traditional tillage (TT) in the North China Plain has maintained grain productivity in the past 50 years. Nonetheless, it has also been a major contributor to global greenhouse gas emissions, biodiversity and soil fertility loss, soil degradation, and even desertification. Permanent raised beds (PRB) have been proposed as a viable solution to achieve sustainable farming in this plain. The effects on soil chemical properties of the PRB treatment and two other treatments, namely, no-tillage and TT treatments, were measured between 2005 and 2011 in the annual double cropping regions of the North China Plain. The soil properties significantly ( P1.35) were significantly ( P<0.05) higher than those under no-tillage and TT. In the cropping zone of PRB, the bulk density was significantly reduced by 14.4%, whereas soil organic carbon, total nitrogen, phosphorus, and potassium and available nitrogen, phosphorus, and potassium in the 0- to 10-cm soil layer were significantly increased by 24.8%, 78.8%, 121.9%, 81.8%, 46.2%, 7.0%, 2.9%, respectively, in comparison with those of TT treatments. Winter wheat and summer maize yields in PRB also underwent a slight increase. Permanent raised beds seem to be an improvement on current farming systems in the North China Plain and valuable for the sustainability of farming in this region.
  • Authors:
    • Ghorbani, R.
    • Khorasani, R.
    • Mahallati, M. N.
    • Koocheki, A.
    • Khorramdel, S.
  • Source: Soil and Tillage Research
  • Volume: 133
  • Issue: October
  • Year: 2013
  • Summary: Carbon sequestration could be an effective way to reduce atmospheric carbon dioxide which is the most important greenhouse gas. Two field experiments were conducted at Agricultural Research Station of Ferdowsi University of Mashhad, Iran, during growing seasons of 2008-2009 and 2009-2010. Four treatments including two low input management systems based on application of cow manure or compost municipal made from house-hold waste, a medium input system and a high input system were applied. In low input system 30 t ha(-1) cow manure or 30 t ha(-1) compost municipal made from house-hold-waste was applied and twice hand weeding were carried out. In medium input system, 15 t ha(-1) compost, 150 kg ha(-1) urea, disking and ploughing, 1.5 l ha(-1) 2,4-D applied at five leaf stage with only one hand weeding. In high input system, management practices included twice disking, twice ploughing, 21 ha(-1) Paraquat applied after planting and 1.5 1 ha(-1) 2,4-D applied at five leaf stage. Results showed that the maximum carbon and nitrogen yields in corn residues observed in high input system (0.8 and 0.02 kg m(-2)) and its minimum were in low input system with using compost (0.5 and 0.01 kg m-2). The highest and lowest labile and recalcitrant carbon rates were observed in low input system with manure (0.92 and 1.05%) and high input system (0.06 and 0.004%), respectively. The maximum sequestered carbon obtained in low input management system with using cow manure (4.1 t ha(-1)) and the minimum sequestered carbon were in high input management system (0.01 t ha(-1)). In low input system due to slow releasing nutrients, long term crop growth and hence higher recalcitrant carbon content of the soil were enhanced which could be an indication of its potential for carbon sequestration in low input management system. (C) 2013 Published by Elsevier B.V.
  • Authors:
    • Mousazadeh, H.
    • Omid, M.
    • Rafiee, S.
    • Khoshnevisan, B.
  • Source: Energy
  • Volume: 58
  • Issue: September
  • Year: 2013
  • Summary: In this study, DEA (data envelopment analysis) was applied to analyze the energy efficiency of wheat farms in order to separate efficient and inefficient growers and to calculate the wasteful uses of energy. Additionally, the degrees of TE (technical efficiency), PTE (pure technical efficiency) and SE (scale efficiency) were determined. Furthermore, the effect of energy optimization on GHG (greenhouse gas) emission was investigated and the total amount of GHG emission of efficient farms was compared with inefficient ones. Based on the results it was revealed that 18% of producers were technically efficient and the average of TE was calculated as 0.82. Based on the BCC (Banker-Charnes-Cooper) model 154 growers (59%) were identified efficient and the mean PTE of these farmers was found to be 0.99. Also, it was concluded that 2075.8 MJ ha(-1) of energy inputs can be saved if the performance of inefficient farms rises to a high level. Additionally, it was observed that the total GHG emission from efficient and inefficient producers was 27133 and 2740.8 kg CO2eq. ha(-1), respectively. By energy optimization the total GHG emission can be reduced to the value of 2684.29 kg CO2eq. ha(-1). (C) 2013 Elsevier Ltd. All rights reserved.
  • Authors:
    • Giltrap, D.
    • Hernandez-Ramirez, G.
    • Kim, D.-G.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 168
  • Issue: March
  • Year: 2013
  • Summary: Rising atmospheric concentrations of nitrous oxide (N2O) contribute to global warming and associated climate change. It is often assumed that there is a linear relationship between nitrogen (N) input and direct N2O emission in managed ecosystems and, therefore, direct N2O emission for national greenhouse gas inventories use constant emission factors (EF). However, a growing body of studies shows that increases in direct N2O emission are related by a nonlinear relationship to increasing N input. We examined the dependency of direct N2O emission on N input using 26 published datasets where at least four different levels of N input had been applied. In 18 of these datasets the relationship of direct N2O emission to N input was nonlinear (exponential or hyperbolic) while the relationship was linear in four datasets. We also found that direct N2O EF remains constant or increases or decreases nonlinearly with changing N input. Studies show that direct N2O emissions increase abruptly at N input rates above plant uptake capacity. The remaining surplus N could serve as source of additional N2O production, and also indirectly promote N2O production by inhibiting biochemical N2O reduction. Accordingly, we propose a hypothetical relationship to conceptually describe in three steps the response of direct N2O emissions to increasing N input rates: (1) linear (N limited soil condition), (2) exponential, and (3) steady-state (carbon (C) limited soil condition). In this study, due to the limited availability of data, it was not possible to assess these hypothetical explanations fully. We recommend further comprehensive experimental examination and simulation using process-based models be conducted to address the issues reported in this review. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Yashima, M.
    • Zsuposne Olah, A.
    • Vago, I.
    • Katai, J.
    • Nagano, H.
    • Kong, Y.
    • Inubushi, K.
  • Source: Soil Science and Plant Nutrition
  • Volume: 59
  • Issue: 3
  • Year: 2013
  • Summary: The production/consumption of greenhouse gases (GHG) in soils are of great importance in global warming, but the involved soil physico-chemical and biological characteristics affecting GHG production and consumption potentials are poorly understood in different land-use types. Carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) production/consumption potentials from four land-use types and 10 soil types in central Japan and eastern Hungary, and their relationships with soil characteristics, were investigated. The average of CO2 production in Japanese soils was significantly higher than that of Hungarian soils due to the relatively higher microbial biomass carbon (MBC) content. N2O production from both countries' soils did not exhibit a significant difference. Most soils except Japanese paddy and soybean soils showed the potentials for CH4 consumption. Forest and grassland soils had relatively higher CO2 and N2O production than orchard and cropland soils for both countries. From regression analyses, it could be concluded that soil total nitrogen (TN) and ammonium-nitrogen (NH4 (+)-N) account for 40.8% and 25.5% variations of the soils' CO2 and N2O productions, respectively. The CH4 consumption was positively correlated with soil carbon/nitrogen (C/N) ratio, while soil MBC availability could account for 15% variation of CH4 consumption under aerobic conditions.
  • Authors:
    • Wander, M. M.
    • Dunn, J. B.
    • Mueller, S.
    • Kwon, H.-Y.
  • Source: Biomass and Bioenergy
  • Volume: 55
  • Issue: August
  • Year: 2013
  • Summary: Current estimates of life cycle greenhouse gas emissions of biofuels produced in the US can be improved by refining soil C emission factors (EF; C emissions per land area per year) for direct land use change associated with different biofuel feedstock scenarios. We developed a modeling framework to estimate these EFs at the state-level by utilizing remote sensing data, national statistics databases, and a surrogate model for CENTURY's soil organic C dynamics submodel (SCSOC). We estimated the forward change in soil C concentration within the 0-30 cm depth and computed the associated EFs for the 2011 to 2040 period for croplands, grasslands or pasture/hay, croplands/conservation reserve, and forests that were suited to produce any of four possible biofuel feedstock systems [corn (Zea Mays L)-corn, corn-corn with stover harvest, switchgrass (Panicum virgatum L), and miscanthus (Miscanthus x giganteus Greef et Deuter)]. Our results predict smaller losses or even modest gains in sequestration for corn based systems, particularly on existing croplands, than previous efforts and support assertions that production of perennial grasses will lead to negative emissions in most situations and that conversion of forest or established grasslands to biofuel production would likely produce net emissions. The proposed framework and use of the SCSOC provide transparency and relative simplicity that permit users to easily modify model inputs to inform biofuel feedstock production targets set forth by policy. (C) 2013 Elsevier Ltd. All rights reserved.
  • Authors:
    • Lal, R.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 28
  • Issue: 2
  • Year: 2013
  • Summary: Ecosystem functions and services provided by soils depend on land use and management. The objective of this article is to review and synthesize relevant information on the impacts of no-till (NT) management of croplands on ecosystem functions and services. Sustainable management of soil through NT involves: (i) replacing what is removed, (ii) restoring what has been degraded, and (iii) minimizing on-site and off-site effects. Despite its merits, NT is adopted on merely similar to 9% of the 1.5 billion ha of global arable land area. Soil's ecosystem services depend on the natural capital (soil organic matter and clay contents, soil depth and water retention capacity) and its management. Soil management in various agro-ecosystems to enhance food production has some trade-offs/disservices (i. e., decline in biodiversity, accelerated erosion and non-point source pollution), which must be minimized by further developing agricultural complexity to mimic natural ecosystems. However, adoption of NT accentuates many ecosystem services: carbon sequestration, biodiversity, elemental cycling, and resilience to natural and anthropogenic perturbations, all of which can affect food security. Links exist among diverse ecosystem services, such that managing one can adversely impact others. For example, increasing agronomic production can reduce biodiversity and deplete soil organic carbon (SOC), harvesting crop residues for cellulosic ethanol can reduce SOC, etc. Undervaluing ecosystem services can jeopardize finite soil resources and aggravate disservices. Adoption of recommended management practices can be promoted through payments for ecosystem services by a market-based approach so that risks of disservices and negative costs can be reduced either through direct economic incentives or as performance payments.
  • Authors:
    • Mihailovic, D. T.
    • Eitzinger, J.
    • Lalic, B.
    • Thaler, S.
    • Jancic, M.
  • Source: The Journal of Agricultural Science
  • Volume: 151
  • Issue: 6
  • Year: 2013
  • Summary: One of the main problems in estimating the effects of climate change on crops is the identification of those factors limiting crop growth in a selected environment. Previous studies have indicated that considering simple trends of either precipitation or temperature for the coming decades is insufficient for estimating the climate impact on yield in the future. One reason for this insufficiency is that changes in weather extremes or seasonal weather patterns may have marked impacts. The present study focuses on identifying agroclimatic parameters that can identify the effects of climate change and variability on winter wheat yield change in the Pannonian lowland. The impacts of soil type under past and future climates as well as the effect of different CO2 concentrations on yield formation are also considered. The Vojvodina region was chosen for this case study because it is a representative part of the Pannonian lowland. Projections of the future climate were taken from the HadCM3, ECHAM5 and NCAR-PCM climate models with the SRES-A2 scenario for greenhouse gas (GHG) emissions for the 2040 and 2080 integration periods. To calibrate and validate the Met&Roll weather generator, four-variable weather data series (for six main climatic stations in the Vojvodina region) were analysed. The grain yield of winter wheat was calculated using the SIRIUS wheat model for three different CO2 concentrations (330, 550 and 1050 ppm) dependent on the integration period. To estimate the effects of climatic parameters on crop yield, the correlation coefficient between crop yield and agroclimatic indices was calculated using the AGRICLIM software. The present study shows that for all soil types, the following indices are the most important for winter wheat yields in this region: (i) the number of days with water and temperature stress, (ii) the accumulated precipitation, (iii) the actual evapotranspiration (ETa) and (iv) the water deficit during the growing season. The high positive correlations between yield and the ETa, accumulated precipitation and the ratio between the ETa and reference evapotranspiration (ETr) for the April-June period indicate that water is and will remain a major limiting factor for growing winter wheat in this region. Indices referring to negative impact on yield are (i) the number of days with a water deficit for the April-June period and (ii) the number of days with maximum temperature above 25 degrees C (summer days) and the number of days with maximum temperature above 30 degrees C (tropical days) in May and June. These indices can be seen as indicators of extreme weather events such as drought and heat waves.