Simulation of drought impact on yield of rainfed wheat and maizein the Piedmont Plain of Mt.Taihang,China

The drought impacts on crop yield were analyzed through calculating multi-time scale standardized precipitation evapotranspiration index(SPEI).APSIM(Agricultural Production Systems Simulator)model was used to simulate about thirty-year yield data of winter wheat-summer maize in the double cropping system under rainfed conditions in Piedmont Plain of Mt.Taihang.The results showed that the APSIM model could reliably simulate wheat and maize yield under rainfed conditions.The maize yield was easily affected by rainfall,and yield fluctuation was relatively large with a variation coefficient of 51.2% .The fluctuation of wheat yield was relatively small with a variation coefficient of 26.4% .High correlation between SPEI and crop yield(P<0.01)was observed that the correlation coefficient was 0.79 between wheat yield and SPEI-3-Apr and 0.88 between maize yield and SPEI-3-Sep.The optimum SPEI values were between 0~2.The established regression equations could describe 61.8% and 87.7% of yield variability of winter wheat and summer maize,respectively.This study indicated that SPEI-3-Apr and SPEI-3-Sep could be optimal drought indices to estimate yields of winter wheat and summer maize under rainfed conditions in Piedmont Plain of Mt.Taihang China,respectively.