Effects of drought on grain yield of spring maize in Northern China

Northern China (NC) accounts for more than 80% of the nation´s total maize planting areas and production, which is the major maize production areas in China, but drought has restrict the stable development of maize in this important area. This led us to investigate the impacts of drought on grain yield of spring maize in NC. We divided the study area into 6 precipitation zones (I~VI) based on the total precipitation during the growing season of spring maize with the interval of 100 mm. The APSIM-Maize model was calibrated and validated for maize phenology and yields in NC. The validated model was then used to estimate the effects of drought on grain yield of spring maize in each precipitation zone. The results for model calibration and evaluation show that simulated growth and development of maize are in good agreement with the corresponding observed values in NC. Maize yield reduction caused by drought decreased from northwest to southeast, which is consistent with the spatial distribution of precipitation during maize growing season. Moreover, maize yield reduction caused by drought reduced gradually from 99.3% in precipitation zone I to 14.8% in precipitation zone VI. The time trends of maize yield reduction caused by drought are not obvious in each precipitation zone during the study period of 1961~2010.