Comparing low moisture availability and relative crop yields on the pan-European scale using the FAO water production function

This paper presents an approach for assessing low soil moisture availability and crop yields on the pan-European scale. It builds on the FAO water production function, linking evapotranspiration reduction simulated with a set of large-scale hydrological models to observed crop yields. Evapotranspiration data of almost 7000 grid cells (0.5° × 0.5°) covering Europe were transformed to 94 NUTS-1 regions to enable comparison with crop yield data and to account for cropland distribution. The multi-model ensemble median evapotranspiration reduction was calculated to accommodate differences between large-scale models. Obviously, Southern and Southeastern Europe showed higher reductions. The evapotranspiration reduction was connected to the relative crop yield (ratio of observed crop yield and simulated potential yield) for six major crops. More significant relationships occurred, for instance, for wheat, maize and potatoes than for rye. No significant relationships occurred in a substantial number of NUTS-1 regions in eastern and northern Europe. Maps show distinct geographical clustering in the strength of the links across Europe in other regions. The R2 of the regression equals 0.76 averaged over all crops, regions and models.