• Authors:
    • Amiri-Jami,Ali Reza
    • Sadeghi,Hussein
    • Shoor,Mahmoud
  • Source: Journal of Asia-Pacific Entomology
  • Volume: 15
  • Issue: 2
  • Year: 2012
  • Summary: The effect of different atmospheric CO2 concentrations on life table parameters and the biology of the cabbage aphid, Brevicoryne brassicae, when fed on two cultivars of ornamental cabbage, was studied in a greenhouse designed for CO2 studies. Aphid performance was influenced by increasing atmospheric CO2 levels, significantly affecting the intrinsic rate of increase (Gamma(m)), finite rate of increase (lambda), mean generation time (T), doubling time (DT), and pre-reproductive period. The longest pre-reproductive period was observed for aphids grown at 380 ppm CO2. The intrinsic rate of natural increase was highest for aphids at 1050 ppm CO2, because of their faster development, high daily rate of progeny production, and higher survivorship. Future elevated CO2 concentrations will enhance aphid population outbreaks and consequently increase the damage caused. (C) Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society, 2012. Published by Elsevier B.V. All rights reserved.
  • Authors:
    • Leytem, A. B.
    • Venterea, R. T.
    • Fixen, P. E.
    • Snyder, C. S.
    • Liebig, M. A.
    • Del Grosso, S. J.
    • Cavigelli, M. A.
    • McLain, J. E.
    • Watts, D. B.
  • Source: Frontiers in Ecology and the Environment
  • Volume: 10
  • Issue: 10
  • Year: 2012
  • Summary: The use of commercial nitrogen (N) fertilizers has led to enormous increases in US agricultural productivity. However, N losses from agricultural systems have resulted in numerous deleterious environmental impacts, including a continuing increase in atmospheric nitrous oxide (N2O), a greenhouse gas (GHG) and an important catalyst of stratospheric ozone depletion. Although associated with about 7% of total US GHG emissions, agricultural systems account for 75% of total US N2O emissions. Increased productivity in the crop and livestock sectors during the past 30 to 70 years has resulted in decreased N2O emissions per unit of production, but N2O emissions from US agriculture continue to increase at a rate of approximately 0.46 teragrams of carbon dioxide equivalents per year (2002-2009). This rate is lower than that during the late 20th century. Improvements in agricultural productivity alone may be insufficient to lead to reduced emissions; implementing strategies specifically targeted at reducing N2O emissions may therefore be necessary. Front Ecol Environ 2012; 10(10): 537-546, doi:10.1890/120054
  • Authors:
    • Grant, T.
    • Carre, A.
    • Eady, S.
  • Source: Journal of Cleaner Production
  • Volume: 28
  • Issue: June
  • Year: 2012
  • Summary: Most agricultural products are produced on farms where there is a mix of activities, resulting in a range of co-products. This raises the issue of how best to model these complex production systems for Life Cycle Assessment, especially where there are benefits imparted by one activity in the mixed farming system to another. On the mixed farm studied, there were significant two-way reference flows (representing 288 t CO2-e/year or 10% of the total farm emissions) between activities producing distinct products (wool, meat, grain) and these were modelled using system expansion. Cropping and sheep activities were modelled as separate sub-processes in the farming system, with unique inputs and outputs identified for each. Co-production from the sheep activity was modelling using allocation, comparing biophysical and economic relationships. Using an economic allocation resulted in different estimates of global warming impact for sheep co-products, with figures varying by 7-52%. When compared to biophysical allocation, economic allocation shifted the environmental burden to the higher value co-products and away from the high resource use products. Using economic allocation, for every kilogram of wool produced there was an estimated 28.7 kg of CO2-e emitted. Amongst the live animal products, the stud rams had the highest estimated carbon footprint (719 kg CO2-e/ram). Amongst the crops, estimates of emissions for the cereal grains averaged 202 kg CO2-e/tonne grain, canola 222 kg CO2-e/tonne and lupins 510 kg CO2-e/tonne, when modelled to include the benefits of the mixed farming system. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.
  • Authors:
    • Hastings, A.
    • Sim, S.
    • King, H.
    • Keller, E.
    • Canals, L. M. I.
    • Flynn, H. C.
    • Wang, S.
    • Smith, P.
  • Source: Global Change Biology
  • Volume: 18
  • Issue: 5
  • Year: 2012
  • Summary: Many assessments of product carbon footprint (PCF) for agricultural products omit emissions arising from land-use change (LUC). In this study, we developed a framework based on IPCC national greenhouse gas inventory methodologies to assess the impacts of LUC from crop production using oil palm, soybean and oilseed rape as examples. Using ecological zone, climate and soil types fromnatural the top 20 producing countries, calculated emissions for transitions from vegetation to cropland on mineral soils under typical management ranged from -4.5 to 29.4 t CO2-eq ha-1 yr-1 over 20 years for oil palm and 1.247.5 t CO2-eq ha-1 yr-1 over 20 years for soybeans. Oilseed rape showed similar results to soybeans, but with lower maximum values because it is mainly grown in areas with lower C stocks. GHG emissions from other land-use transitions were between 62% and 95% lower than those from natural vegetation for the arable crops, while conversions to oil palm were a sink for C. LUC emissions were considered on a national basis and also expressed per-tonne-of-oil-produced. Weighted global averages indicate that, depending on the land-use transition, oil crop production on newly converted land contributes between -3.1 and 7.0 t CO2-eq t oil production-1 yr-1 for palm oil, 11.950.6 t CO2-eq t oil production-1 yr-1 for soybean oil, and 7.731.4 t CO2-eq t oil production-1 yr-1 for rapeseed oil. Assumptions made about crop and LUC distribution within countries contributed up to 66% error around the global averages for natural vegetation conversions. Uncertainty around biomass and soil C stocks were also examined. Finer resolution data and information (particularly on land management and yield) could improve reliability of the estimates but the framework can be used in all global regions and represents an important step forward for including LUC emissions in PCFs.
  • Authors:
    • Hubbs, M. D.
    • Franzluebbers, A. J.
    • Norfleet, M. L.
  • Source: Journal of Soil and Water Conservation
  • Volume: 67
  • Issue: 5
  • Year: 2012
  • Summary: Simulation models that are sensitive to management, edaphic factors, and climate could provide insights into how land owners and producers might be able to sequester soil organic carbon (C) and engage in emerging carbon markets. In this study, the soil conditioning index (SCI) embedded in the Revised Universal Soil Loss Equation (RUSLE2) model was used to predict (1) potential soil organic C sequestration under conventional and conservation management of a diversity of cotton cropping systems throughout the Cotton Belt and (2) relative influences of soil texture, slope, climatic conditions, and management on potential soil organic C sequestration. Across 10 regions of the Cotton Belt, SCI scores ranked in the following order: perennial pasture > no-till cropping systems > conventional tillage cotton. Variations in significance of SCI scores occurred among 5 different no-till cropping systems within regions of the Cotton Belt. For example, 7 of the 10 regions had significantly (p <= 0.05) greater SCI scores (linked to greater soil organic C sequestration) when monoculture cotton was grown with winter cover crop than without.Variation in SCI was dominated by management (46%) and slope (24%) and very little affected by climate (7%) and soil texture (1%). Increasingly wetter climatic conditions (as expressed by increasing precipitation to potential evapotranspiration) had a negative influence on SCI scores for all management systems and land slopes evaluated, but particularly for moldboard-plowed cotton on sloping land, With a linear relationship between SCI and soil organic C sequestration, predicted soil organic C sequestration averaged -0.31 +/- 0.19 Mg C ha(-1) y(--1) (-280 +/- 170 lb ac(-1) yr(-1)) under conventionally tilled cotton, 0.12 +/- 0.06 Mg C ha(-1) y(-1) (103 +/- 52 lb ac(-1) yr(-1)) under various no-till crop rotations, and 0.26 +/- 0.02 Mg C ha(-1) y(-1) (231 +/- 20 lb ac(-1) yr(-1)) under perennial pasture. Cotton production with conventional tillage could only be expected to maintain soil organic C under a best-case scenario and would lose substantial soil organic C under most other scenarios. Simulations showed the strong, positive influence that conservation agricultural management has to sequester soil organic C, irrespective of climate, slope, and texture.
  • Authors:
    • Brandt, S. A.
    • Malhi, S. S.
    • Huang, G.
    • Liang, C.
    • Gan, Y.
    • Katepa-Mupondwa, F.
  • Source: The International Journal of Life Cycle Assessment
  • Volume: 17
  • Issue: 1
  • Year: 2012
  • Summary: Best agricultural practices can be adopted to increase crop productivity and lower carbon footprint of grain products. The aims of this study were to provide a quantitative estimate of the carbon footprint of selected oilseed crops grown on the semiarid northern Great Plains and to determine the effects of N fertilization and environments on the carbon footprint. Five oilseed crops, Brassica napus canola, Brassica rapa canola, Brassica juncea canola, B. juncea mustard, and Sinapis alba mustard, were grown under the N rates of 0, 25, 50, 100, 150, 200, and 250 kg N ha(-1) at eight environsites (location x year combinations) in Saskatchewan, Canada. Straw and root decomposition and various production inputs were used to calculate greenhouse gas emissions and carbon footprints. Emissions from the production, transportation, storage, and delivery of N fertilizer to farm gates accounted for 42% of the total greenhouse gas emissions, and the direct and indirect emission from the application of N fertilizer in oilseed production added another 31% to the total emission. Emissions from N fertilization were nine times the emission from the use of pesticides and 11 times that of farming operations. Straw and root decomposition emitted 120 kg CO(2)eq ha(-1), contributing 10% to the total emission. Carbon footprint increased slightly as N rates increased from 0 to 50 kg N ha(-1), but as N rates increased from 50 to 250 kg N ha(-1), carbon footprint increased substantially for all five oilseed crops evaluated. Oilseeds grown at the humid Melfort site emitted 1,355 kg CO(2)eq ha(-1), 30% greater than emissions at the drier sites of Scott and Swift Current. Oilseeds grown at Melfort had their carbon footprint of 0.52 kg CO(2)eq kg(-1) of oilseed, 45% greater than that at Scott (0.45 kg CO(2)eq kg(-1) of oilseed), and 25% greater than that at Swift Current (0.45 kg CO(2)eq kg(-1) of oilseed). Carbon footprint of oilseeds was a function of the rate of N fertilizer, and the intensity of the functionality varied between environments. Key to lower carbon footprint in oilseeds is to improve N management practices.
  • Authors:
    • James, A.
    • Solah, V.
    • Biswas, W.
    • Gunady, M.
  • Source: Journal of Cleaner Production
  • Volume: 28
  • Year: 2012
  • Summary: A life cycle greenhouse gas (GHG) assessment of 1 kJ of strawberries, button mushrooms (Agaricus bisporus), and romaine/cos lettuces (Lactuca sativa) transported to retail outlets in Western Australia (WA) was examined and compared. The study included pre-farm, on-farm, and post-farm emissions. The pre-farm stage included GHG emissions from agricultural machinery and chemical production, and transport of raw materials (spawn, peat, and compost) in mushrooms. The on-farm stage included GHG emissions from agricultural machinery operation, chemical use, water for irrigation, waste generated, as well as electricity and energy consumption. The post-farm stage included transport of produce to Distribution Center (DC), storage in DC, and transport to retail outlets. The 'hotspots' or the stages that emit the highest GHG were determined for strawberries, button mushrooms and romaine/cos lettuces. The results have shown that the life cycle GHG emissions of strawberries and lettuces were higher than mushrooms due to intensive agricultural machinery operations during the on-farm stage. Mushrooms, however have significantly higher GHG emissions during pre-farm stage due to transport of peat, spawn, and compost. (C) 2011 Elsevier Ltd. All rights reserved.
  • Authors:
    • Del Grosso, S.
    • Halvorson, A.
  • Source: Journal of Environmental Quality
  • Volume: 41
  • Issue: 5
  • Year: 2012
  • Summary: A nitrogen (N) source comparison study was conducted to further evaluate the effects of inorganic N source and placement on growing-season and non-crop period soil nitrous oxide (N2O). Commercially available controlled-release N fertilizers were evaluated for their potential to reduce N2O emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn (Zea mays L.) production system. Controlled-release N fertilizers evaluated were: a polymer-coated urea (ESN), stabilized urea (SuperU), and UAN+AgrotainPlus (SuperU and AgrotainPlus contain nitrification and urease inhibitors). Each N source was surface band applied (202 kg N ha(-1)) near the corn row at emergence and watered into the soil the next day. Subsurface banded ESN (ESNssb) and check (no N applied) treatments were included. Nitrous oxide fluxes were measured during two growing seasons and aft er harvest using static, vented chambers. All N sources had significantly lower growing-season N2O emissions than granular urea (0.7% of applied N), with UAN+AgrotainPlus (0.2% of applied N) and ESN (0.3% of applied N) having lower emissions than UAN (0.4% of applied N). Similar trends were observed when expressing N2O emissions on a grain yield and N uptake basis. Corn grain yields were not different among N sources but were greater than the check. Selection of N fertilizer source can be a mitigation practice for reducing N2O emissions in NT, irrigated corn in semiarid areas. In our study, UAN+AgrotainPlus consistently had the lowest level of N2O emissions with no yield loss.
  • Authors:
    • Shamshuddin, J.
    • Arifin, A.
    • Heshmati, M.
    • Majid, N.
  • Source: Geoderma
  • Volume: 175
  • Year: 2012
  • Summary: Land degradation is the loss in the productivity of land resources due to many factors, especially soil erosion. Nutrient depletion and soil organic carbon (SOC) loss are the main impacts of erosion which not only cause declining crop yield, but also induce off-site impacts, such as eutrophication and greenhouse gas (GHG) emission. The main objective of this study was to estimate the depletion of N, P, K and SOC due to soil erosion prevailing in the three agro-ecological zones within the Merck catchment, Iran. The erosion rate and eroded plant nutrients (N, P and K) as well as SOC were estimated using MPSIAC model. The results showed that the most important factor affecting land degradation in the Merek catchment is inter-rill erosion, covering an area of about 20%, which in turn is promoted by deforestation and overgrazing. The erosion rate in the agriculture area, rangeland and forest is 14.47, 16.60 and 18.57 t ha(-1) yr(-1), respectively. The respective predicted annual N depletion by erosion is 23.5, 26.6 and 32.8 kg ha(-1) yr(-1) in agriculture area, rangeland and forest zone, while that of P is 0.230 and 0.290 and 0.220 kg ha(-1) yr(-1). The depletion of K in agriculture area is 7.01, rangeland is 6.25 and forest is 636 kg ha(-1) yr(-1). The highest loss in SOC is in the forest with a value of 414 kg ha(-1) yr(-1) while the lowest is in the agriculture area with a value of 213 kg ha(-1) yr(-1). The high loss of SOC in the forest zone is due to serious soil erosion, which is accelerated by sloping land. It is concluded that the MPSIAC model used in this study is able to satisfactorily predict soil erosion rate and the loss of N, P, K and SOC at the catchment scale in the semi-arid region of Iran. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Garcia, L. A.
    • Ahuja, L. R.
    • Islam, A.
    • Ma, L.
    • Saseendran, A. S.
  • Source: Web Of Knowledge
  • Volume: 55
  • Issue: 6
  • Year: 2012
  • Summary: Changes in evapotranspiration demand due to global warming will have a profound impact on irrigation water demand and agricultural productivity. In this study, the effects of possible future anthropogenic climate change on reference evapotranspiration (ETo) were evaluated using the Penman-Monteith equation. The combined effect of temperature and elevated CO2 concentrations on ETo was the major focus of this study. The ETo under the General Circulation Model (GCM) projected climate change scenarios was estimated for a location in Colorado. Multi-model ensemble climate change scenarios were generated from 112 Bias Corrected and Spatially Disaggregated (BCSD) projections from the World Climate Research Program (WCRP) archive, which cover different levels of greenhouse gas emissions. Results showed a decrease in ETo demand with increases in CO2 levels, which greatly moderated the increase in ETo due to increasing temperature. The effect of increases in CO2 levels up to 450 ppm off set the effect of about 1 degrees C rise in temperature. Simulation results with projected climate change scenarios, without considering the effects of CO2 levels, showed an 8.3%, 14.7% and 21.0% increase in annual ETo during the 2020s, 2050s, and 2080s, respectively, when simulation was carried out using an ensemble of the 112 projections. When the effect of elevated CO2 levels was also considered in combination with projected changes in temperature, changes in annual ETo demand varied from -1.5% to 5.5%, -10.4% to 6.7%, and -19.7% to 6.6% during the 2020s, 2050s, and 2080s, respectively, depending on the different climate change scenarios considered and the relationship or equation used for estimating the effect of elevated CO2 on stomatal resistance term in the Penman-Monteith equation.