• 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:
    • Jayet, P.-A.
    • Castell, J.-F.
    • Szopa, S.
    • Clerino, P.
    • Leconte-Demarsy, D.
    • Humblot, P.
  • Source: ECOLOGICAL ECONOMICS
  • Volume: 85
  • Year: 2013
  • Summary: As a result of anthropogenic activities, ozone is produced in the surface atmosphere, causing direct damage to plants and reducing crop yields. By combining a biophysical crop model with an economic supply model we were able to predict and quantify this effect at a fine spatial resolution. We applied our approach to the very varied French case and showed that ozone has significant productivity and land-use effects. A comparison of moderate and high ozone scenarios for 2030 shows that wheat production may decrease by more than 30% and barley production may increase by more than 14% as surface ozone concentration increases. These variations are due to the direct effect of ozone on yields as well as to modifications in land use caused by a shift toward more ozone-resistant crops: our study predicts a 16% increase in the barley-growing area and an equal decrease in the wheat-growing area. Moreover, mean agricultural gross margin losses can go as high as 2.5% depending on the ozone scenario, and can reach 7% in some particularly affected regions. A rise in ozone concentration was also associated with a reduction of agricultural greenhouse gas emissions of about 2%, as a result of decreased use of nitrogen fertilizers. One noteworthy result was that major impacts, including changes in land use, do not necessarily occur in ozone high concentration zones, and may strongly depend on farm systems and their adaptation capability. Our study suggests that policy makers should view ozone pollution as a major potential threat to agricultural yields. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Govindaraj, M.
    • Prabukumar, G.
    • Arunachalam, P.
    • Kannan, P.
  • Source: African Journal of Agricultural Research
  • Volume: 8
  • Issue: 21
  • Year: 2013
  • Summary: Atmospheric rise of CO 2, N 2O and CH 4 over years, accelerated increase in global temperature, has led to uncertainty in monsoon rainfall and also leading to recurrence of drought, which in turn is severely affecting crop productivity and livelihood security of the farmers in Semi Arid Tropics. Agriculture contributes considerable amount of CO 2, N 2O and CH 4 emission into the atmosphere through different soil and crop management practices. Nevertheless agricultural activities contribute to global warming. The medium of crop production, soil is one of the major sinks of global warming gaseous and it helps to sequester more carbon and cut the N 2O emission by adopting smart soil and crop management techniques. Biochar is one of the viable organic amendments to combat climate change and sustain the soil health with sustainable crop production. It is an anaerobic pyrolysis product derived from organic sources and store carbon on a long term basis in the terrestrial ecosystem and also capable of reducing greenhouse gases (GHG) emission from soil to the atmosphere. Biochar application improved the soil health, increase the carbon capture and storage, reduce the GHG emission and enhance the crop yield with sustained soil health, which enables to meet out the food grain needs of the ever growing population.
  • 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:
    • Vida, G.
    • Varga, B.
    • Bencze, S.
    • Komaromi, J.
    • Veisz, O.
  • Source: Acta Agronomica Hungarica
  • Volume: 61
  • Issue: 4
  • Year: 2013
  • Summary: Over the last two centuries the atmospheric CO 2 level has exhibited a consistent rise, leading to an increase in the greenhouse effect. This level is now 35% higher than it was before the industrial revolution. On the basis of various scenarios from the Special Report on Emissions it is expected to rise from the present level of 385 ppm to 650-970 ppm by the end of the 21st century. Plant biomass and resistance of winter wheat to various powdery mildew pathotypes were investigated at normal (400 ppm) and enhanced (700 ppm) atmospheric CO 2 levels in a greenhouse. Wheat cultivars Ukrainka and Mv Hombar, and 12 lines from the mapping population developed from their cross and exhibiting different level of resistance were tested. The results showed that the atmospheric CO 2 level had little influence on the resistance of winter wheat to powdery mildew infections based on the percentage of leaf area covered whole plant percentage severity. In response to higher atmospheric CO 2 level there was an increase in the aboveground biomass of the winter wheat genotypes tested in the present work, leading to an increase in plant height and in stem and leaf weight. However, the number of tillers and the grain yield did not increase compared with the values recorded at normal atmospheric CO 2 level.
  • Authors:
    • Franzluebbers, A. J.
    • Andrews, S. S.
    • Kome, C. E.
  • Source: JOURNAL OF SOIL AND WATER CONSERVATION
  • Volume: 68
  • Issue: 4
  • Year: 2013
  • Summary: Simple, yet reliable models are needed to quantify soil organic carbon (SOC) changes for the wide diversity of agricultural management conditions in the United States. We compared the outputs of two relatively simple models currently available for farmers and government-financed farm support agencies: the Carbon (C) Management Evaluation Tool for Voluntary Reporting of Greenhouse Gases (COMET-VR) and the Soil Conditioning Index (SCI). Simulations were conducted for 18 locations throughout the United States for five soil textural regimes (loamy sand, sandy loam, silt loam, clay loam, and silty clay loam), three tillage management systems (conventional tillage [CT], minimum tillage [MT], and no tillage [NT]), and two crop rotations (wheat [Triticum aestivum L.]-potato [Solanum tuberosum L.] and wheat-four-year alfalfa [Medicago sativa L.] in western states and corn [Zea mays L.]-soybean [Glycine max L.] and corn-soybean-wheat in eastern states). Both models ranked SOC change as NT > MT > CT, whereby SOC change decreased with increasing soil disturbance with tillage However, models were divergent with regards to soil texture; SOC change was greater in coarse-textured than in fine-textured soils with COMET-VR, but SOC change was lower in coarse-textured than in fine-textured soils with SCI. For crop rotations, SOC change was greater or equal in simpler than in more complex rotation with COMET-VR, but smaller in simpler than in more complex rotations with SCI. Overall, SOC sequestration predicted by COMET-VR was positively related to SCI score, especially when accounting for differences in environmental conditions of a location. Our results suggest that both Models have value and limitations and that measures of SOC sequestration are predictable with these tools under a diversity of typical management conditions in the United States.
  • Authors:
    • Huelsbergen, K.-J.
    • Munch, J. C.
    • Kuestermann, B.
  • Source: European Journal of Agronomy
  • Volume: 49
  • Issue: August
  • Year: 2013
  • Summary: Two factorial long-term field experiments were carried out at the experimental site of Scheyern, located in southern Germany, 40 km north of Munich (48 degrees 30'0' N, 11 degrees 26'60' E). Here three soil tillage systems were investigated: CT (conventional tillage with moldboard plough, 25 cm plowing depth), RT1 (reduced tillage with chisel plow, 18 cm working depth), and RT2 (reduced tillage with chisel plow, 8 cm working depth). At the same time, three fertilization systems were analyzed (high (N3), medium (N2) and low (N1) mineral N input) with a crop rotation of winter wheat (Triticum aestivum L) - potatoes (Solanum tuberosum L.) - winter wheat-corn (Zea mays L). The long-term effects of tillage and fertilization on yields, soil properties, nitrogen and energy efficiency, as well as greenhouse gas emissions (GGE) were investigated for the period of 1994-2005. On average conventional tillage (CT) produced yields of 8.03 (N1), 8.82 (N2) and 8.88 (N3) GE (grain equivalents) ha(-1) yr(-1); reduced tillage (RT1) yields of 7.82 (N1), 8.54 (N2) and 9.10 (N3) GE ha(-1) yr(-1) and RT2 yields of 6.9 (Ni), 7.82 (N2) and 8.6 (N3) GE ha(-1) yr(-1). The benefit of reduced soil tillage over CT. is a lower consumption of diesel fuel (reduced by 35%) and fossil energy (by 10%), C sequestration and N accumulation in soil. We recorded the highest soil organic carbon (SOC) in the RT2 treatments with the lowest tillage intensity (52.5 Mg ha(-1)) and the lowest SOC reserves in the CT plowed treatments (41.1 Mg ha(-1)). During the reported period, SOC reserves in the plowed treatments decreased by about 300 kg C ha-1 yr-1, whereas they increased by 150-500 kg C ha(-1) yr(-1) in the chiseled treatments. Similar results were achieved with the soil organic nitrogen (SON) reserves based on the type of tillage. This amounted to around 4000 kg ha-1 (CT), 4500 kg ha (RT1) and more than 5000 kg N ha-1 (RT2). The RT1 treatments were marked by high nutrient and energy efficiency. The disadvantage of reduced tillage lies in higher pesticide consumption and stronger soil compaction. The influence of reduced tillage was more pronounced in RT2 than in RT1 (higher SOC and SON content, higher soil dry bulk density, lower consumption of diesel fuel, higher pesticide input). The significant decreases in yield in the RT2 treatments reduced the nitrogen and energy efficiency and raised yield-related greenhouse gas emissions (GGE) in comparison to the RT1 treatments. In the case of reduced tillage combined with high N doses (RT1/N3, RT2/N2, RT2/N3), high N2O emissions of 10 to 12 kg ha(-1) yr(-1) were measured using closed chambers. It was found that as input of mineral N increased, GGE for tillage treatments, both area and yield related also increased. In RT1/N1, negative net GGE were recorded due to high C sequestration combined with moderate N2O and CO2 emissions (-220 kg CO2 (eq) ha(-1) yr(-1), -28 kg CO2 eq GE-(1)), whereas CT/N3 produced the highest net GGE (3587 kg CO2 (eq) ha(-1) yr(-1), 404 kg CO2 eq GE(-1)). (C) 2013 Elsevier B.V. All rights reserved.
  • 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.