Hermine Mitter (Austria) 1; Katrin Karner (Austria) 1; Erwin Schmid (Austria) 1
1 - University of Natural Resources and Life Sciences, Vienna
Climate information appears to be underutilized in water management in agriculture. A systematic and integrated analysis of effective adaptation measures may inform decision making of farmers, policy-makers and water management authorities and may facilitate the uptake and use of climate information. Therefore, we aim at modeling interactions between hydrological processes, the groundwater status, and land use and management choices under consideration of different climate change scenarios. We have developed a spatially explicit integrated modeling framework consisting of climate change scenarios, a crop rotation model, the bio-physical process model EPIC (Environmental Policy Integrated Climate), and a non-linear bottom-up economic land use optimization model BiomAT.
EPIC is used to simulate annual yields and irrigation water use on cropland, intensive and extensive grassland, and vineyards for a future period of 31 years. These land use categories are simulated with various adaptation management options including crop rotations, fertilization intensities, mowing frequency, and irrigation intensities. EPIC simulates – inter alia – the hydrological processes at field scale, i.e. precipitation, evapotranspiration, percolation, surface and sub-surface runoff as well as the CO2 fertilization effect. In BiomAT, the groundwater balance is represented in a dynamic and spatially explicit way using monthly outputs from EPIC on percolation and irrigation. This allows us to assess efficient land use and management choices for adaptation considering hydrological restrictions, whereby the monthly irrigation water withdrawal from the groundwater aquifer is limited to monthly groundwater renewal. Furthermore, we calculate the energy demand for agricultural irrigation considering different technologies such as sprinkler and drip irrigation as well as diesel and electric engines.
The integrated modeling framework is applied to the semi-arid case study region of Seewinkel in eastern Austria. Model results for the case study region show that higher net-benefits can be achieved through an expansion of vineyards, and high irrigation water and fertilizer inputs if both, mean temperature and mean annual precipitation sums increase in the next decades. Large economic losses are modeled if irrigation water is limited under a climate change scenario where mean temperatures increase and mean annual precipitation sums decrease, compared to a historical period. The results underline the relevance of accurate and timely climate information for decision-making and thus optimal agricultural adaptation. Including a water balance in the land use optimization model highlights the importance of considering land and water interactions for agricultural adaptation in a water-constrained region.