Climate change impacts on agro-climatic indices derived from downscaled weather generator scenarios for eastern Denmark

The agricultural sector supports the growing world population with food and successful crop production is highly dependent on the prevailing climatic conditions. A modelling analysis of projected future changes in agroclimatic conditions is presented for eastern Denmark, focussing on indices of drainage need, field traffic ability, water shortage and relative production (the ratio between actual and potential production). Projected climatic change from 11 climate model simulations were downscaled by perturbing a weather generator calibrated on meteorological data (hourly rainfall and daily air temperature, wind speed, sunshine hours, relative humidity), from a location in eastern Denmark. The analysis was carried out for the control period (1983-2012), the near future (2030-2059) and the far future (2070-2099). 3000 year long weather series were generated for each period and used to drive the agro-ecological model, Daisy. The Daisy model setup included two structurally different soils and two crops. Silage maize was found to benefit from the longer potential growing season in the future, but it is likely that the unchanged or slightly decreased summer rainfall will not be sufficient to meet the increased water requirements and irrigation might be necessary to reach the production potential. The winter wheat cultivar used in the analysis was found to have a shorter active growing season in the future, and so yields actually reduced. The effects of increased winter rainfall do not show a clear change in trafficability, but mean drainage flow increased by an average of 10% in the near future and 16% in the far future. Thus, the results suggest a potential for increased future crop production in eastern Denmark, however the choice of crops and cultivars needs consideration, and maintenance of the drainage system should also be a priority.