• Authors:
    • Mushtaq,S.
    • Maraseni,T. N.
    • Reardon-Smith,K.
    • Bundschuh,J.
    • Jackson,T.
  • Source: Journal of Cleaner Production
  • Volume: 103
  • Year: 2015
  • Summary: Robust understanding of possible trade-offs and synergies between climate change, energy and water sector policies is critical to achieving economically viable and environmentally sound agricultural production systems in a low-carbon water-constrained economy, in which greenhouse gas (GHG) emissions are penalized and water savings rewarded. Accurate assessment of the potential costs/benefits of investment decisions can help to optimize the economic efficiency of agricultural production while minimizing environmental impacts. This paper presents a novel integrated framework, based on carbon and water accounting, which enables analysis of potential trade-offs between water savings, energy consumption, GHG emissions and economic costs/benefits associated with the adoption of new water efficient irrigation technologies. The framework was applied to an irrigated lucerne cropping system in eastern Australia and compares the costs/benefits of old roll-line sprinkler irrigation systems against new pressurized systems. Positive synergies were found with the adoption of the new technology, which saved both water and energy use, reduced total GHG emissions and resulted in net economic returns across a range of carbon prices. The results of this study provide support for an integrated evidence-based approach to policy development and strategic decision-making and for the prioritization of investments on both economic and environmental grounds. (C) 2014 Elsevier Ltd. All rights reserved.
  • Authors:
    • Hossain,M. K.
    • Strezov,V.
    • Nelson,P. F.
  • Source: Pedosphere
  • Volume: 25
  • Issue: 5
  • Year: 2015
  • Summary: To investigate the potential effects of wastewater sludge and sludge biochar on growth, yield and metal bioaccumulation of cherry tomato ( Lycopersicon esculentum L.), a pot experiment was carried out under greenhouse environment with three different treatments, control soil (CP), soil with wastewater sludge (SS) and soil with sludge biochar (SB), to reveal the comparative effect between the amendments of wastewater sludge and sludge biochar. The soil used for pot experiment was Chromosol. Wastewater sludge and sludge biochar produced through pyrolysis process at 550°C were applied at 10 t ha -1. No significant difference was found in growth and production of cherry tomatoes between wastewater sludge and sludge biochar applications to the soil. The accumulation rates of metals in the fruits were lower in the treatment with sludge biochar than in the treatment with wastewater sludge. The study highlights the benefits of risk mitigation from toxic metal accumulation in fruits using wastewater sludge and sludge biochar as soil conditioners.
  • Authors:
    • Solaiman,Zakaria M.
    • Anawar,Hossain M.
  • Source: Pedosphere
  • Volume: 25
  • Issue: 5
  • Year: 2015
  • Summary: Biochar addition to soil is currently being considered as a means to sequester carbon while simultaneously improving soil health, soil fertility and agronomic benefits. The focus of this special issue is on current research on the effects of biochar application to soil for overcoming diverse soil constraints and recommending further research relating to biochar application to soil. The biochar research has progressed considerably with important key findings on agronomic benefits, carbon sequestration, greenhouse gas emissions, soil acidity, soil fertility, soil health, soil salinity, etc., but more research is required before definitive recommendations can be made to end-users regarding the effects of biochar application across a range of soils, climates and land management practices.
  • Authors:
    • Trebicki,P.
    • Nancarrow,N.
    • Cole,E.
    • Bosque-Perez,N. A.
    • Constable,F. E.
    • Freeman,A. J.
    • Rodoni,B.
    • Yen,A. L.
    • Luck,J. E.
    • Fitzgerald,G. J.
  • Source: Global Change Biology
  • Volume: 21
  • Issue: 9
  • Year: 2015
  • Summary: Current atmospheric CO 2 levels are about 400 mol mol -1 and are predicted to rise to 650 mol mol -1 later this century. Although the positive and negative impacts of CO 2 on plants are well documented, little is known about interactions with pests and diseases. If disease severity increases under future environmental conditions, then it becomes imperative to understand the impacts of pathogens on crop production in order to minimize crop losses and maximize food production. Barley yellow dwarf virus (BYDV) adversely affects the yield and quality of economically important crops including wheat, barley and oats. It is transmitted by numerous aphid species and causes a serious disease of cereal crops worldwide. This study examined the effects of ambient (aCO 2; 400 mol mol -1) and elevated CO 2 (eCO 2; 650 mol mol -1) on noninfected and BYDV-infected wheat. Using a RT-qPCR technique, we measured virus titre from aCO 2 and eCO 2 treatments. BYDV titre increased significantly by 36.8% in leaves of wheat grown under eCO 2 conditions compared to aCO 2. Plant growth parameters including height, tiller number, leaf area and biomass were generally higher in plants exposed to higher CO 2 levels but increased growth did not explain the increase in BYDV titre in these plants. High virus titre in plants has been shown to have a significant negative effect on plant yield and causes earlier and more pronounced symptom expression increasing the probability of virus spread by insects. The combination of these factors could negatively impact food production in Australia and worldwide under future climate conditions. This is the first quantitative evidence that BYDV titre increases in plants grown under elevated CO 2 levels.
  • Authors:
    • Visser,F.
    • Dargusch,P.
    • Smith,C.
    • Grace,P. R.
  • Source: Journal of Cleaner Production
  • Volume: 103
  • Year: 2015
  • Summary: The various initiatives in the market place to quantify the sustainability levels of products are putting pressure on farmers to demonstrate a reduction in the environmental impacts of their crop management practices, and in particular with the lowering of the carbon footprints of their crops. At present there is no internationally accredited common method or carbon footprint model which generates site specific and LCA aligned emission estimates. The application of the Crop Carbon Progress Calculator (CCAP) is demonstrated for an irrigated cotton 'farm to ship' case study in Australia where we determine that the progress made in the 2011 crop against a 2002 crop base year amounts to 44% reduction in GHG emission levels. We estimate that for this particular case study the total carbon footprint of producing a bale of cotton up to ship's side or point of export is 323 kg CO 2e. This includes 182 kg CO 2e from the farm production phase, 73.1 kg CO 2e from the gin to port supply chain, and 68.1 kg CO 2e that results from emission from the stock piled gin trash at the gins. It appears that a feasible option to avoid these trash emissions is to incorporate the waste at farm level. Our analysis shows that this could generate an emissions credit of 48.8 kg CO 2e per bale at farm level, which will amount to a 27% reduction in the farm emissions footprint and a 15% reduction in the whole farm to ship carbon footprint. Due to a number of site specific environmental and crop management factors, there can be significant variances in crop carbon footprint outcomes.
  • Authors:
    • Navarro, J.
    • Li, J.
    • Nolan, M.
    • Crossman, N. D.
    • Bryan, B. A.
    • Connor, J. D.
  • Source: Primary Research Article
  • Volume: 21
  • Issue: 11
  • Year: 2015
  • Summary: Competition for land is increasing, and policy needs to ensure the efficient supply of multiple ecosystem services from land systems. We modelled the spatially explicit potential future supply of ecosystem services in Australia's intensive agricultural land in response to carbon markets under four global outlooks from 2013 to 2050. We assessed the productive efficiency of greenhouse gas emissions abatement, agricultural production, water resources, and biodiversity services and compared these to production possibility frontiers (PPFs). While interacting commodity markets and carbon markets produced efficient outcomes for agricultural production and emissions abatement, more efficient outcomes were possible for water resources and biodiversity services due to weak price signals. However, when only two objectives were considered as per typical efficiency assessments, efficiency improvements involved significant unintended trade-offs for the other objectives and incurred substantial opportunity costs. Considering multiple objectives simultaneously enabled the identification of land use arrangements that were efficient over multiple ecosystem services. Efficient land use arrangements could be selected that meet society's preferences for ecosystem service provision from land by adjusting the metric used to combine multiple services. To effectively manage competition for land via land use efficiency, market incentives are needed that effectively price multiple ecosystem services.
  • Authors:
    • Chauhan,Y. S.
    • Thorburn,P.
    • Biggs,J. S.
    • Wright,G. C.
  • Source: Research Article
  • Volume: 66
  • Issue: 11
  • Year: 2015
  • Summary: With the aim of increasing peanut production in Australia, the Australian peanut industry has recently considered growing peanuts in rotation with maize at Katherine in the Northern Territory - a location with a semi-arid tropical climate and surplus irrigation capacity. We used the well-validated APSIM model to examine potential agronomic benefits and long-term risks of this strategy under the current and warmer climates of the new region. Yield of the two crops, irrigation requirement, total soil organic carbon (SOC), nitrogen (N) losses and greenhouse gas (GHG) emissions were simulated. Sixteen climate stressors were used; these were generated by using global climate models ECHAM5, GFDL2.1, GFDL2.0 and MRIGCM232 with a median sensitivity under two Special Report of Emissions Scenarios over the 2030 and 2050 timeframes plus current climate (baseline) for Katherine. Effects were compared at three levels of irrigation and three levels of N fertiliser applied to maize grown in rotations of wet-season peanut and dry-season maize (WPDM), and wet-season maize and dry-season peanut (WMDP). The climate stressors projected average temperature increases of 1°C to 2.8°C in the dry (baseline 24.4°C) and wet (baseline 29.5°C) seasons for the 2030 and 2050 timeframes, respectively. Increased temperature caused a reduction in yield of both crops in both rotations. However, the overall yield advantage of WPDM increased from 41% to up to 53% compared with the industry-preferred sequence of WMDP under the worst climate projection. Increased temperature increased the irrigation requirement by up to 11% in WPDM, but caused a smaller reduction in total SOC accumulation and smaller increases in N losses and GHG emission compared with WMDP. We conclude that although increased temperature will reduce productivity and total SOC accumulation, and increase N losses and GHG emissions in Katherine or similar northern Australian environments, the WPDM sequence should be preferable over the industry-preferred sequence because of its overall yield and sustainability advantages in warmer climates. Any limitations of irrigation resulting from climate change could, however, limit these advantages.
  • Authors:
    • Chapman, S.
    • McLean, G.
    • Zheng, B.
    • Chenu, K.
    • Hammer, G.
    • Lobell, D.
  • Source: Global Change Biology
  • Volume: 21
  • Issue: 11
  • Year: 2015
  • Summary: Characterization of drought environment types (ETs) has proven useful for breeding crops for drought-prone regions. Here, we consider how changes in climate and atmospheric carbon dioxide (CO 2) concentrations will affect drought ET frequencies in sorghum and wheat systems of northeast Australia. We also modify APSIM (the Agricultural Production Systems Simulator) to incorporate extreme heat effects on grain number and weight, and then evaluate changes in the occurrence of heat-induced yield losses of more than 10%, as well as the co-occurrence of drought and heat. More than six million simulations spanning representative locations, soil types, management systems, and 33 climate projections led to three key findings. First, the projected frequency of drought decreased slightly for most climate projections for both sorghum and wheat, but for different reasons. In sorghum, warming exacerbated drought stresses by raising the atmospheric vapor pressure deficit and reducing transpiration efficiency (TE), but an increase in TE due to elevated CO 2 more than offset these effects. In wheat, warming reduced drought stress during spring by hastening development through winter and reducing exposure to terminal drought. Elevated CO 2 increased TE but also raised radiation-use efficiency and overall growth rates and water use, thereby offsetting much of the drought reduction from warming. Second, adding explicit effects of heat on grain number and grain size often switched projected yield impacts from positive to negative. Finally, although average yield losses associated with drought will remain generally higher than that for heat stress for the next half century, the relative importance of heat is steadily growing. This trend, as well as the likely high degree of genetic variability in heat tolerance, suggests that more emphasis on heat tolerance is warranted in breeding programs. At the same time, work on drought tolerance should continue with an emphasis on drought that co-occurs with extreme heat.
  • Authors:
    • Davidson, B.
    • White, R.
  • Source: IOP Conference Series: Earth and Environmental Science
  • Volume: 25
  • Issue: 1
  • Year: 2015
  • Summary: Data for cropping and pastoral enterprises in south eastern Australia were used in a cost-effectiveness analysis to assess the feasibility of abating greenhouse gas (GHG) emissions through storing soil carbon (C) as soil organic matter under the Australian government's Carbon Farming Initiative. We used the C credit value for 2013-14 of $24.15 per tonne of CO2- equivalent (CO2-e) and a C storage rate of 0.5 tonne C/hectare/year for conversion of cropland to pasture. Given that a change of enterprise is driven primarily by farmer returns, we found that none of the changes were feasible at current prices, with the exception of wheat to cattle or sheep in an irrigated system, and dryland cotton to cattle or sheep. Given that our model scenario assumed the most favourable economic factors, it is unlikely that increased soil C storage through a change from cropping to pasture can make a significant contribution to abating Australia's CO2 emissions. However, of greater concern to society is the methane emissions from grazing cattle or sheep, which would negate any gain in soil C under pasture, except for a switch from dryland cropping to sheep. © Published under licence by IOP Publishing Ltd.
  • Authors:
    • Rust, J.
    • Kimber, S.
    • Herridge, D.
    • Rose, T.
    • Zwieten, L. V.
    • Cowie, A.
    • Morris, S.
  • Source: Article
  • Volume: 395
  • Issue: 1/2
  • Year: 2015
  • Summary: Background and aims: Acid soils constrain legume growth and biochars have been shown to address these constraints and enhance biological N 2 fixation in glasshouse studies. A dissection of causal mechanisms from multiple crop field studies is lacking. Methods: In a sub-tropical field study, faba bean ( Vicia faba L.) was cultivated in rotation with corn ( Zea mays) following amendment of two contrasting biochars, compost and lime in a rhodic ferralsol. Key soil parameters and plant nutrient uptake were investigated alongside stable 15N isotope methodologies to elucidate the causal mechanisms for enhanced biological N 2 fixation and crop productivity. Results: Biological N 2 fixation was associated with plant Mo uptake, which was driven by reductions in soil acidity following lime and papermill (PM) biochar amendment. In contrast, crop yield was associated with plant P and B uptake, and amelioration of soil pH constraints. These were most effectively ameliorated by PM biochar as it addressed both pH constraints and low soil nutrient status. Conclusions: While liming resulted in the highest biological N 2 fixation, biochars provided greater benefits to faba bean yield by addressing P nutrition and ameliorating Al toxicity.