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Kersebaum, K., Kroes, J., Gobin, A., Takáč, J., Hlavinka, P., Trnka, M., et al. (2016). Assessing uncertainties of water footprints using an ensemble of crop growth models on winter wheat. Water, 8(12), 571.
Abstract: Crop productivity and water consumption form the basis to calculate the water footprint (WF) of a specific crop. Under current climate conditions, calculated evapotranspiration is related to observed crop yields to calculate WF. The assessment of WF under future climate conditions requires the simulation of crop yields adding further uncertainty. To assess the uncertainty of model based assessments of WF, an ensemble of crop models was applied to data from five field experiments across Europe. Only limited data were provided for a rough calibration, which corresponds to a typical situation for regional assessments, where data availability is limited. Up to eight models were applied for wheat. The coefficient of variation for the simulated actual evapotranspiration between models was in the range of 13%–19%, which was higher than the inter-annual variability. Simulated yields showed a higher variability between models in the range of 17%–39%. Models responded differently to elevated CO2 in a FACE (Free-Air Carbon Dioxide Enrichment) experiment, especially regarding the reduction of water consumption. The variability of calculated WF between models was in the range of 15%–49%. Yield predictions contributed more to this variance than the estimation of water consumption. Transpiration accounts on average for 51%–68% of the total actual evapotranspiration.
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Gobin, A., Kersebaum, K., Eitzinger, J., Trnka, M., Hlavinka, P., Takáč, J., et al. (2017). Variability in the Water Footprint of Arable Crop Production across European Regions. Water, 9(2), 93.
Abstract: Crop growth and yield are affected by water use during the season: the green water footprint (WF) accounts for rain water, the blue WF for irrigation and the grey WF for diluting agri-chemicals. We calibrated crop yield for FAO’s water balance model “Aquacrop” at field level. We collected weather, soil and crop inputs for 45 locations for the period 1992–2012. Calibrated model runs were conducted for wheat, barley, grain maize, oilseed rape, potato and sugar beet. The WF of cereals could be up to 20 times larger than the WF of tuber and root crops; the largest share was attributed to the green WF. The green and blue WF compared favourably with global benchmark values (R² = 0.64–0.80; d = 0.91–0.95). The variability in the WF of arable crops across different regions in Europe is mainly due to variability in crop yield (c̅v̅ = 45%) and to a lesser extent to variability in crop water use (c̅v̅ = 21%). The WF variability between countries (c̅v̅ = 14%) is lower than the variability between seasons (c̅v̅ = 22%) and between crops (c̅v̅ = 46%). Though modelled yields increased up to 50% under sprinkler irrigation, the water footprint still increased between 1% and 25%. Confronted with drainage and runoff, the grey WF tended to overestimate the contribution of nitrogen to the surface and groundwater. The results showed that the water footprint provides a measurable indicator that may support European water governance.
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Sandhu, H., Wratten, S. D., Porter, J. R., Costanza, R., Pretty, J., & Reganold, J. P. (2016). Mainstreaming ecosystem services into future farming solutions. The Solutions Journal, 7(2), 40–47.
Abstract: Agriculture has made remarkable advances in fulfilling the food and nutritional requirement of expanding human numbers worldwide. There are several sustainable farming systems that contribute to overall biodiversity conservation and associated ecosystem services. Yet agricultural practices that have come to predominate since the second half of the 20th century have led to the overuse of fossil fuel-based inputs, unsustainable exploitation of natural resources, and loss of biodiversity. These outcomes also have high costs to human health and the environment. Continuing with largely energy-intense, wasteful, polluting, and unsustainable agriculture is no longer a viable option for future world food security and human well-being. There is an urgent need for forms of agricultural production that improve natural capital and ecosystem services (ES) in food systems worldwide. Mainstreaming ES into future agriculture requires protocols to replace some of the nonrenewable resources (e.g. fossil fuel-based pesticides and fertilizers) with renewable resources (ES such as biological control of insect pests or nitrogen fixation by legumes). The protocols presented here have been tested in different agricultural systems that enable farmland to simultaneously provide food and a range of ecosystem services. Recent research demonstrates that managed systems with these protocols exhibit higher economic value of ecosystem services. Thus, there is need to support the deployment of these protocols through various policy mechanisms for the long-term sustainability of agriculture.
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Bennett, E., Carpenter, S. R., Gordon, L. J., Ramankutty, N., Balvanera, P., Campbell, B., et al. (2014). Toward a more resilient agriculture. The Solutions Journal, 5(5), 65–75.
Abstract: Agriculture is a key driver of change in the Anthropocene. It is both a critical factor for human well-being and development and a major driver of environmental decline. As the human population expands to more than 9 billion by 2050, we will be compelled to find ways to adequately feed this population while simultaneously decreasing the environmental impact of agriculture, even as global change is creating new circumstances to which agriculture must respond. Many proposals to accomplish this dual goal of increasing agricultural production while reducing its environmental impact are based on increasing the efficiency of agricultural production relative to resource use and relative to unintended outcomes such as water pollution, biodiversity loss, and greenhouse gas emissions. While increasing production efficiency is almost certainly necessary, it is unlikely to be sufficient and may in some instances reduce long-term agricultural resilience, for example, by degrading soil and increasing the fragility of agriculture to pest and disease outbreaks and climate shocks. To encourage an agriculture that is both resilient and sustainable, radically new approaches to agricultural development are needed. These approaches must build on a diversity of solutions operating at nested scales, and they must maintain and enhance the adaptive and transformative capacity needed to respond to disturbances and avoid critical thresholds. Finding such approaches will require that we encourage experimentation, innovation, and learning, even if they sometimes reduce short-term production efficiency in some parts of the world.
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Dietrich, J. P., Schmitz, C., Lotze-Campen, H., Popp, A., & Muller, C. (2014). Forecasting technological change in agriculture-An endogenous implementation in a global, and use model. Technological Forecasting and Social Change, 81, 236–249.
Abstract: Technological change in agriculture plays a decisive role for meeting future demands for agricultural goods. However, up to now, agricultural sector models and models on land use change have used technological change as an exogenous input due to various information and data deficiencies. This paper provides a first attempt towards an endogenous implementation based on a measure of agricultural land use intensity. We relate this measure to empirical data on investments in technological change. Our estimated yield elasticity with respect to research investments is 029 and production costs per area increase linearly with an increasing yield level. Implemented in the global land use model MAgPIE (”Model of Agricultural Production and its Impact on the Environment”) this approach provides estimates of future yield growth. Highest future yield increases are required in Sub-Saharan Africa, the Middle East and South Asia. Our validation with FAO data for the period 1995-2005 indicates that the model behavior is in line with observations. By comparing two scenarios on forest conservation we show that protecting sensitive forest areas in the future is possible but requires substantial investments into technological change. (C) 2013 Elsevier Inc. All rights reserved.
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