Abstract: Effect of soil moisture on crop growth and yield were performed on the variation of crop growth conditions and biomass growth.In order to achieve soil moisture indexes for normal growing wheat during its different growth/development phases,field experimental data of Zhengzhou test site of Henan Institute of Meteorological Science from 1994 to 1996 and 1997 to 1998 were used in this paper.Statistical analyses were carried out between observed information of growth condition as well as biomass increase in current stage and soil moisture conditions in previous stage,then the relationships between soil moisture,yield components and yield were established.By using mathematical methods,appropriate soil moisture indexes were determined which aimed at relative better growth and higher yield respectively.The results would provide basis for establishing dynamic evaluation models on evaluating drought risk of winter wheat.

Key words: Winter wheat, Growing status, Yield traits, Soil moisture, Index