• Authors:
    • Wang, Y. Y.
    • Zhao, F. H.
    • Sun, X. M.
    • Wen, X. F.
    • Bao, X. Y.
  • Source: PLOS ONE
  • Volume: 9
  • Issue: 10
  • Year: 2014
  • Summary: Interannual variation in plant phenology can lead to major modifications in the interannual variation of net ecosystem production (NEP) and net biome production (NBP) as a result of recent climate change in croplands. Continuous measurements of carbon flux using the eddy covariance technique were conducted in two winter wheat and summer maize double-cropped croplands during 2003-2012 in Yucheng and during 2007-2012 in Luancheng on the North China Plain. Our results showed that the difference between the NEP and the NBP, i.e., the crop economic yield, was conservative even though the NEP and the NBP for both sites exhibited marked fluctuations during the years of observation. A significant and positive relationship was found between the annual carbon uptake period (CUP) and the NEP as well as the NBP. The NEP and the NBP would increase by 14.8 +/- 5.2 and 14.7 +/- 6.6 g C m(-2) 22 yr(-1), respectively, if one CUP-day was extended. A positive relationship also existed between the CUP and the NEP as well as the NBP for winter wheat and summer maize, respectively. The annual air temperature, through its negative effect on the start date of the CUP, determined the length of the CUP. The spring temperature was the main indirect factor controlling the annual carbon sequestration when a one-season crop (winter wheat) was considered. Thus, global warming can be expected to extend the length of the CUP and thus increase carbon sequestration in croplands.
  • Authors:
    • Fritz, A.
    • Bowden, R.
    • Bergtold, J.
    • Nalley, L. L.
    • Tack, J.
    • Barkley, A.
  • Source: AGRONOMY JOURNAL
  • Volume: 106
  • Issue: 1
  • Year: 2014
  • Summary: Wheat (Triticum aestivum L.) yields in Kansas have increased due to wheat breeding and improved agronomic practices, but are subject to climate and disease challenges. The objective of this research is to quantify the impact of weather, disease, and genetic improvement on wheat yields of varieties grown in 11 locations in Kansas from 1985 to 2011. Wheat variety yield data from Kansas performance tests were matched with comprehensive location-specific disease and weather data, including seasonal precipitation, monthly air temperature, air temperature and solar radiation around anthesis, and vapor pressure deficit (VPD). The results show that wheat breeding programs increased yield by 34 kg ha(-1) yr(-1). From 1985 through 2011, wheat breeding increased average wheat yields by 917 kg ha(-1), or 27% of total yield. Weather was found to have a large impact on wheat yields. Simulations demonstrated that a 1 degrees C increase in projected mean temperature was associated with a decrease in wheat yields of 715 kg ha(-1), or 21%. Weather, diseases, and genetics all had significant impacts on wheat yields in 11 locations in Kansas during 1985 to 2011.
  • Authors:
    • Engelbrecht, D.
    • Thamo, T.
    • Barton, L.
    • Biswas, W. K.
  • Source: JOURNAL OF CLEANER PRODUCTION
  • Volume: 83
  • Year: 2014
  • Summary: Agriculture production contributes to global warming directly via the release of carbon dioxide (CO2), methane and nitrous oxide emissions, and indirectly through the consumption of inputs such as fertilizer, fuel and herbicides. We investigated if including a grain legume (Lupinus angustifolius) in a cropping rotation, and/or applying agricultural lime to increase the pH of an acidic soil, decreased greenhouse gas (GHG) emissions from wheat production in a semi-arid environment by conducting a streamlined life cycle assessment analysis that utilized in situ GHG emission measurements, rather than international default values. We also assessed the economic viability of each GHG mitigation strategy. Incorporating a grain legume in a two year cropping rotation decreased GHG emissions from wheat production by 56% on a per hectare basis, and 35% on a per tonne of wheat basis, primarily by lowering nitrogen fertilizer inputs. However, a large incentive ($93 per tonne of carbon dioxide equivalents reduced) was required for the inclusion of grain legumes to be financially attractive. Applying lime was profitable but increased GHG emissions by varying amounts depending upon whether the lime was assumed to dissolve over one, five or 10 years. We recommend further investigating the impact of liming on both CO2 and non-CO2 emissions to accurately account for its effect on GHG emissions from agricultural production.
  • Authors:
    • Singh, S. D.
    • Paul, R. K.
    • Sehgal, V. K.
    • Chakraborty, D.
    • Chattaraj, S.
    • Daripa, A.
    • Pathak, H.
  • Source: AGRICULTURE ECOSYSTEMS & ENVIRONMENT
  • Volume: 197
  • Year: 2014
  • Summary: Crop water requirement (CWR) under the projected climate change could be mediated through changes in other weather parameters including the air temperature. The present study was directed to assess the on-farm water requirement in wheat crop in future, in semi-arid Indo-Gangetic Plains of India, through field and computer simulations. Field simulation using temperature gradient tunnels shows 18% higher crop evapotranspiration (ET c) and 17% increase in root water extraction at 3.6°C elevated temperature compared to 1.5°C increase over the ambient. A time series model (ARIMA) with long-term (1984-2010) weather data of the experimental site and a global climate model (IPCC-SRES HADCM3) were used to simulate the potential ET (ET 0) of wheat for 2020-2021 and 2050-2051 years. The crop coefficient ( Kc) values for these years were generated through Kc-CGDD (Cumulative growing-degree-days) relation by using LARS-WG model-derived daily minimum and maximum temperatures. The CWR and NIR (Net Irrigation Requirement) are likely to be less in projected years even though air temperatures increase. The CWR reduces in ARIMA outputs owing to a lower reference ET (ET 0) due to decline in solar radiation. Under IPCC-SRES scenarios, the ET c-crop phenophase relation [CGDD-LGP (length of growing period) response] may offset the effect of rising temperature and a net decline in CWR is observed. It may be likely that the effect of temperature increase on CWR is manifested mostly through its relation with crop phenophase (thermal requirement to complete a specific growth stage) and not the temperature effect on ET 0 per se. This is certainly a ray of hope in managing the depleting irrigation water resources in the semi-arid wheat-growing regions of the IGP.
  • Authors:
    • Ziadat, F.
    • Tesfaye, S.
    • Bayu, W.
    • Demelash, N.
    • Sommer, R.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 100
  • Issue: 3
  • Year: 2014
  • Summary: Restoring soil fertility in smallholder farming systems is essential to sustain crop production. An experiment was conducted in 2011 and 2012 to study the effect of compost and inorganic fertilizer application on soil chemical properties and wheat yield in northwest Ethiopia. Full factorial combinations of four levels of compost (0, 4, 6, 8 t ha(-1)) and three levels of inorganic fertilizers (0-0, 17.3-5, 34.5-10 kg N-P ha(-1)) were compared in a randomized complete block design with three replications. In 2012, two sets of trials were conducted: one was the repetition of the 2011 experiment on a new experimental plot and the second was a residual effect study conducted on the experimental plots of 2011. Results showed that in the year of application, applying 6 t compost ha(-1) with 34.5-10 kg N-P ha(-1) gave the highest significant grain yield. In the residual effect trial, 8 t compost ha(-1) with 34.5-10 kg N-P ha(-1) gave 271 % increase over the control. Grain protein content increased 21 and 16 % in the current and residual effect trials, respectively, when 8 t compost ha(-1) was applied; it increased 11 and 14 % in the current and residual effect trials, respectively, when 34.5-10 kg N-P ha(-1) was applied. Under the current and residual effects of 8 t compost ha(-1), SOM increased 108 and 104 %; available P 162 and 173 %; exchangeable Ca 16.7 and 17.4 %; and CEC 15.4 and 17.1 %, respectively. Applying 6 t compost ha(-1) with 34.5-10 kg N-P ha(-1) is economically profitable with 844 % MRR.
  • Authors:
    • Sternberg, M.
    • Bonfil, D. J.
    • Lifschitz, D.
    • Eshel, G.
  • Source: AGRICULTURE ECOSYSTEMS & ENVIRONMENT Volume: 195 Pages:
  • Volume: 195
  • Year: 2014
  • Summary: The adoption of no-till (NT) cultivation practices in field crops such as wheat ( Triticum aestivum) may mitigate increasing global concentrations of atmospheric CO 2. Little information is currently available on the effects of rainfed wheat cultivation practices on the carbon exchange in arid regions. The goal of the present study was to quantify the long-term (13 years) effects of tillage and fertilization on soil CO 2 fluxes in wheat fields under arid climatic conditions (230 mm rainfall), and evaluate the carbon turnover. It was hypothesized that adopting a NT practice would improve the carbon exchange in wheat fields under arid conditions. During 2007-2009, four different practices were studied in a Calcic Xerosol in Southern Israel: conventional tillage with fertilization (CT + F), conventional tillage without fertilization (CT), no-till with fertilization (NT + F), and no-till without fertilization (NT). CO 2 output as soil respiration efflux and CO 2 input as aboveground net primary production (ANPP) were calculated. The annual carbon loss as CO 2 efflux was higher under NT vs. CT practices both with fertilization (144.91 vs. 110.87 g C m -2y -1) and without it (136.43 vs. 99.52 g C m -2y -1). Similar trends were obtained for the carbon gain derived from wheat ANPP: 132.16 vs. 88.94 g C m -2y -1 for the fertilized treatments, and 110.9 vs. 75.04 g C m -2y -1 for the unfertilized practices under NT and CT, respectively. Furthermore, the physical soil-sealing layer, commonly found under CT practices due to raindrops' impact on the bare soil, highly affects the soil water regime, and also negatively affects soil gas exchange under CT. Our results clearly support the long-term advantages of adopting NT practices, where plant residues create a protective cover on the soil surface, in rainfed arid regions for all good reasons: better rainwater utilization and soil aeration, enhancing soil organic carbon content, and increasing yields.
  • Authors:
    • Campbell, C. A.
    • Lemke, R. L.
    • Chai, Q.
    • Liang, C.
    • Gan, Y. T.
    • Zentner, R. P.
  • Source: NATURE COMMUNICATIONS
  • Volume: 5
  • Year: 2014
  • Summary: Wheat is one of the world's most favoured food sources, reaching millions of people on a daily basis. However, its production has climatic consequences. Fuel, inorganic fertilizers and pesticides used in wheat production emit greenhouse gases that can contribute negatively to climate change. It is unknown whether adopting alternative farming practices will increase crop yield while reducing carbon emissions. Here we quantify the carbon footprint of alternative wheat production systems suited to semiarid environments. We find that integrating improved farming practices (that is, fertilizing crops based on soil tests, reducing summerfallow frequencies and rotating cereals with grain legumes) lowers wheat carbon footprint effectively, averaging -256 kg CO2 eq ha(-1) per year. For each kg of wheat grain produced, a net 0.027-0.377 kg CO2 eq is sequestered into the soil. With the suite of improved farming practices, wheat takes up more CO2 from the atmosphere than is actually emitted during its production.
  • Authors:
    • Chang, S. X.
    • Zeng, D. H.
    • Wu, F. P.
    • Hu, Y. L.
  • Source: BIOLOGY AND FERTILITY OF SOILS
  • Volume: 50
  • Issue: 8
  • Year: 2014
  • Summary: Application of crop residues and its biochar produced through slow pyrolysis can potentially increase carbon (C) sequestration in agricultural production systems. The impact of crop residue and its biochar addition on greenhouse gas emission rates and the associated changes of soil gross N transformation rates in agricultural soils are poorly understood. We evaluated the effect of wheat straw and its biochar applied to a Black Chernozemic soil planted to barley, two growing seasons or 15 months (at the full-bloom stage of barley in the second growing season) after their field application, on CO 2 and N 2O emission rates, soil inorganic N and soil gross N transformation rates in a laboratory incubation experiment. Gross N transformation rates were studied using the 15N isotope pool dilution method. The field experiment included four treatments: control, addition of wheat straw (30 t ha -1), addition of biochar pyrolyzed from wheat straw (20 t ha -1), and addition of wheat straw plus its biochar (30 t ha -1 wheat straw+20 t ha -1 biochar). Fifteen months after their application, wheat straw and its biochar addition increased soil total organic C concentrations ( p=0.039 and <0.001, respectively) but did not affect soil dissolved organic C, total N and NH 4+-N concentrations, and soil pH. Biochar addition increased soil NO 3--N concentrations ( p=0.004). Soil CO 2 and N 2O emission rates were increased by 40 ( p<0.001) and 17% ( p=0.03), respectively, after wheat straw addition, but were not affected by biochar application. Straw and its biochar addition did not affect gross and net N mineralization rates or net nitrification rates. However, biochar addition doubled gross nitrification rates relative to the control ( p<0.001). Our results suggest that land application of biochar, as opposed to the application of the raw wheat straw, could suppress CO 2 and N 2O emissions and enhance soil C sequestration. However, the implications of the increased soil gross nitrification rate and NO 3--N in the biochar addition treatment for long-term NO 3--N dynamics and N 2O emissions need to be further studied.
  • Authors:
    • Damalas, C. A.
    • Fotiadis, S.
    • Antoniadis, V.
    • Koutroubas, S. D.
  • Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
  • Volume: 100
  • Issue: 2
  • Year: 2014
  • Summary: The application of sewage sludge (SS) to agricultural land can improve soil fertility and physical properties, and enhance crop production. This field study was conducted for two consecutive growing seasons to investigate the influence of SS application on winter wheat growth, grain yield, N accumulation, translocation and use, and on trace elements concentrations in soil and wheat plants under Mediterranean conditions. Treatments consisted of three rates of SS, i.e. 20, 40, and 60 Mg dry weight ha(-1) year(-1), one rate of inorganic fertilizer (IF, 120 kg N ha(-1) year(-1) plus 80 kg P2O5 ha(-1) year(-1)), and an unamended control. The application of SS resulted in tall plants with high early dry matter and N accumulation similar to or significantly higher than those obtained with IF. The lowest SS application rate resulted in grain yield similar to that obtained with IF. Nitrogen use efficiency (NUE) in SS treatments was mainly determined by uptake efficiency, which decreased with increasing SS application rate. Values of NUE and biomass production efficiency with the lowest SS rate were similar to those obtained with IF. SS application resulted in increased concentrations of total and DTPA-extractable trace elements in the soil after the first year, but concentrations were much lower than the regulation limits. Concentrations of Cu, Mn and Zn in wheat plants did not exceed those obtained with IF. Overall, SS could be considered for use as a fertilizer in wheat production systems in the area, serving also as an alternative method of SS disposal.
  • Authors:
    • de Cortazar-Atauri,I. G.
    • Huard, F.
    • Bourgeois, G.
    • Caubel, J.
    • Launay, M.
    • Bancal, M. O.
    • Brisson, N.
  • Source: AGRICULTURE ECOSYSTEMS & ENVIRONMENT
  • Volume: 197
  • Year: 2014
  • Summary: Since weather has a major influence on the occurrence and development of crop diseases, valuable insight toward future agricultural planning emerges with assessment tools to evaluate fungal disease pressure and crop regional suitability under projected future climatic conditions. The aim of this study was to develop two climatic indicators, the average infection efficiency (AIE) and the number of infection days (NID), to quantify the potential effects of weather on the intensity and occurrence of pathogen infection. First, a simple and continuous infection function accounting for daily temperature and leaf wetness duration variations was implemented. The function was then parameterized from published data sets for five major contrasting fungal diseases affecting crops in Northern France: phoma of oilseed rape, late blight of potato, downy mildew of grape, leaf rust of wheat and net blotch of barley. Finally, AIE and NID were calculated for the recent past (1970-2000) and the future A1B climate scenario (2070-2100). An overall decrease in the risk of infection was shown for potato late blight and downy mildew of grapevine for all months during the period when the host plant is susceptible to infection. There were greater differences for the other three diseases, depending on the balance between warmer temperatures and lower humidity. The future climate would result in a later onset of disease and higher infection pressure in late autumn. In spring, for brown rust of wheat and net blotch of barley, the climatic risk for infection is expected to occur earlier but would result in lower infection pressure in May. These findings highlighted the need to use an infra-annual (monthly or seasonally) scale to achieve a relevant analysis of the impact of climate change on the infection risk. The described indicators can easily be adapted to other pathogens and may be useful for agricultural planning at the regional scale and in the medium term, when decision support tools are required to anticipate future trends and the associated risks of crop diseases.