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Thursday, November 5, 2009: 9:30 AM
Convention Center, Room 410, Fourth Floor
Abstract:
Climate change including increasing CO2 concentration of the atmosphere will affect crop growth as well as soil water and nutrient dynamics in Germany very differently due to different regional changes of climate and site specific boundary conditions. This will require an adaptation of crop management regarding cultivation, water and nutrient management. Based on simulations with the agro-ecosystem model HERMES, the impact of climate change on crop growth and water and nutrient management was assessed for 10 different regions accross Germany using a a small scale soil map and a downscaled climate change scenario A1B from the GCM ECHAM5.
Results indicate that the effects of climate change on crop production and management will vary across Germany depending on the specific regional projection and site properties. Without considering the effect of elevated CO2 crop yield under climate change was mainly reduced compared to the reference time slice. Including the effect of elevated CO2 on photosynthesis and transpiration in the simulation yielded in an increase in average crop yields in many cases. However, regions in East-Germany may suffer from more frequent dry spells, where the CO2 effect was estimated to be not sufficient to level out the negative impact of water shortage.
Nitrogen use efficiency was reduced under typical summer drought conditions. In wetter regions the elevated temperature led to an increase of nitrogen mineralisation. Therefore, in dryer regions the required nitrogen supply by fertilization for maximum yields was estimated to increase although the potential yield decreased compared to the reference period while in the more humid regions the nitrogen requirements remained unchanged although higher yields were expected. Yields, nitrogen mineralisation and nitrogen use efficiency could be improved by irrigation. The consideration of the indirect CO2 effect reduced the increase of the irrigation demand.
Results indicate that the effects of climate change on crop production and management will vary across Germany depending on the specific regional projection and site properties. Without considering the effect of elevated CO2 crop yield under climate change was mainly reduced compared to the reference time slice. Including the effect of elevated CO2 on photosynthesis and transpiration in the simulation yielded in an increase in average crop yields in many cases. However, regions in East-Germany may suffer from more frequent dry spells, where the CO2 effect was estimated to be not sufficient to level out the negative impact of water shortage.
Nitrogen use efficiency was reduced under typical summer drought conditions. In wetter regions the elevated temperature led to an increase of nitrogen mineralisation. Therefore, in dryer regions the required nitrogen supply by fertilization for maximum yields was estimated to increase although the potential yield decreased compared to the reference period while in the more humid regions the nitrogen requirements remained unchanged although higher yields were expected. Yields, nitrogen mineralisation and nitrogen use efficiency could be improved by irrigation. The consideration of the indirect CO2 effect reduced the increase of the irrigation demand.