Modeling climate change and biophysical impacts of crop production in the Austrian Marchfeld Region

Climate change affects major biophysical processes in agricultural crop production (e. g. evaporation of plants and soils, nutrient cycles, and growth of plants). This analysis aims to assess some of these effects by simulating regional climate projections that are integrated in the biophysical process model EPIC (Environmental Policy Integrated Climate). Statistical climate models have been developed for six weather parameters based on daily weather records of a weather station in the Austrian Marchfeld region from 1975 to 2006. These models have been used to estimate daily weather parameters for the period 2007-2038. The resulting projections have been compared to climate scenarios provided from the TYNDALL Centre for Climate Change Research, which are based on General Circulation Models (GCMs). The comparison indicates some differences, namely a smaller temperature increase and a higher precipitation amount in the TYNDALL data. Both climate datasets have been used to simulate impacts of climate change on crop yields, topsoil organic carbon content, and nitrate leaching with EPIC and thus to perform a sensitivity analysis of EPIC. Yield impacts have been assessed for four simulated crops, i.e. 6.2 t/ha for winter wheat for statistical climate projections compared to 5.7 t/ha for TYNDALL scenarios, 10.6 t/ha for corn compared to 10.5 t/ha, 3.9 t/ha for sunflower compared to 3.7 t/ha, and 4.5 t/ha for spring barley compared to 4.3 t/ha-all values as an average over the period 2007-2038. Smaller differences have been simulated for topsoil organic carbon content i.e. 55.1 t/ha for the statistical climate projections compared to 55.3 t/ha for the TYNDALL scenarios and nitrate leaching i.e. 7.1 kg/ha compared to 11.1 kg/ha. All crop yields as well as topsoil organic carbon content and nitrate leaching show highest sensitivity to temperature and solar radiation.