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Daccache, A., Ciurana, J. S., Diaz, J. A. R., & Knox, J. W. (2014). Water and energy footprint of irrigated agriculture in the Mediterranean region. Environ. Res. Lett., 9(12), 124014.
Abstract: Irrigated agriculture constitutes the largest consumer of freshwater in the Mediterranean region and provides a major source of income and employment for rural livelihoods. However, increasing droughts and water scarcity have highlighted concerns regarding the environmental sustainability of agriculture in the region. An integrated assessment combining a gridded water balance model with a geodatabase and GIS has been developed and used to assess the water demand and energy footprint of irrigated production in the region. Modelled outputs were linked with crop yield and water resources data to estimate water (m(3) kg(-1)) and energy (CO2 kg(-1)) productivity and identify vulnerable areas or `hotspots’. For a selected key crops in the region, irrigation accounts for 61 km(3) yr(-1) of water abstraction and 1.78 Gt CO2 emissions yr-1, with most emissions from sunflower (73 kg CO2/t) and cotton (60 kg CO2/t) production. Wheat is a major strategic crop in the region and was estimated to have a water productivity of 1000 tMm(-3) and emissions of 31 kg CO2/t. Irrigation modernization would save around 8 km(3) of water but would correspondingly increase CO2 emissions by around +135\%. Shifting from rain-fed to irrigated production would increase irrigation demand to 166 km(3) yr(-1) (+137\%) whilst CO2 emissions would rise by +270\%. The study has major policy implications for understanding the water-energy-food nexus in the region and the trade-offs between strategies to save water, reduce CO2 emissions and/or intensify food production.
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Daccache, A. (2014). Assessing water and energy footprint of irrigated agriculture in the Mediterranean. FACCE MACSUR Mid-term Scientific Conference, 3(S) Sassari, Italy.
Abstract: Agriculture in the Mediterranean, one of the water scarcest regions in the world is by far the largest water consuming sector. Dwindling water supply, increase in drought frequency and uncertainties associated with climate change have raised the alerts on the region’s food security and environmental sustainability. In this study, a large geo-database of global climate, soil and crop were combined with national irrigation statistics to run a water balance model to estimate the theoretical irrigation volumetric needs of the Mediterranean main strategic crops and their relative CO2 emissions. When associated with the reported crop yield and water resources availability, the spatial variability of water (m3/kg) and energy (CO2/kg) productivity across the Mediterranean region are obtained and vulnerable areas are identified. The estimated total water needs for the Mediterranean irrigated agriculture under current climate, land cover and irrigation methods was estimated to be around 46km3/year releasing more than 3Mt of CO2 in the atmosphere only from water abstraction and farm application. Currently, 59% of total irrigation water needs are located in catchments that are classified as under high and extremely high water risk. With climate change, water resources are expected to become scarcer and agriculture more dependent on irrigation to satisfy the continuous increase in food demand. Adaptation and mitigation options to tackle water scarcity and improve productivity under current and future climate will be discussed.
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Curnel, Y. R. W. (2014). Meteorological risks as drivers of environmental innovation in agro-ecosystem management. FACCE MACSUR Mid-term Scientific Conference, 3(S) Sassari, Italy.
Abstract: The extreme weather events, projected to increase both in frequency and magnitude with climate change have significant impact on agro-ecosystem services and pose severe limitations to sustainable agricultural land management. The proposed activities start from the hypothesis that these meteorological risks act as drivers of environmental innovation in agro-ecosystem management. These activities deal with risks associated with extreme weather phenomena and with risks of biological origin (e.g. pests and diseases). In order to reach this objective, the following elements of the chain of risk should be considered: • Hazard (assessment of the likely frequency and magnitude of extreme meteorological events)• Impact (analysis of the potential bio-physical and socio-economic impact of extreme weather events on agro-ecosystems)• Vulnerability (identification of the most vulnerable agro-ecosystems)• Risk Management (uncovering innovative risk management and adaptation options)These activities will concentrate on promoting a robust and flexible framework by demonstrating its performance across Belgian agro-ecosystems, and by ensuring its relevance to policy makers and practitioners. Impacts developed from physically based models will not only provide information on the state of the damage at any given time, but also assist in understanding the links between different factors causing damage and determining bio-physical vulnerability. Socio-economic impacts will enlarge the basis for vulnerability mapping, risk management and adaptation options. A strong expert and end-user network will be established to help exploiting project results to meet user needs
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Crout, N. M. J., Craigon, J., Cox, G. M., Jao, Y., Tarsitano, D., Wood, A. T. A., et al. (2014). An objective approach to model reduction: Application to the Sirius wheat model. Agricultural and Forest Meteorology, 189-190(100), 211–219.
Abstract: An existing simulation model of wheat growth and development, Sirius, was evaluated through a systematic model reduction procedure. The model was automatically manipulated under software control to replace variables within the model structure with constants, individually and in combination. Predictions of the resultant models were compared to growth analysis observations of total biomass, grain yield, and canopy leaf area derived from 9 trials conducted in the UK and New Zealand under optimal, nitrogen limiting and drought conditions. Model performance in predicting these observations was compared in order to evaluate whether individual model variables contributed positively to the overall prediction. Of the 1 1 1 model variables considered 16 were identified as potentially redundant. Areas of the model where there was evidence of redundancy were: (a) translocation of biomass carbon to grain; (b) nitrogen physiology; (c) adjustment of air temperature for various modelled processes; (d) allowance for diurnal variation in temperature; (e) vernalisation (f) soil nitrogen mineralisation (g) soil surface evaporation. It is not suggested that these are not important processes in real crops, rather, that their representation in the model cannot be justified in the context of the analysis. The approach described is analogous to a detailed model inter-comparison although it would be better described as a model intra-comparison as it is based on the comparison of many simplified forms of the same model. The approach provides automation to increase the efficiency of the evaluation and a systematic means of increasing the rigour of the evaluation.
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Challinor, A. E. A. (2014). How have uncertainties in projected yields changed between AR4 and AR5..
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