Evaluation Method for Winter Wheat Yield Loss of Drought Disaster in North China

The North China was divided into fifteen regions according to similarity principle of climate and agricultural production level. The daily meteorological drought composite indices( CI) were calculated based on the daily temperature and precipitation data of observation stations from 1970 to 2010,and the contiguous soil moisture status observation data was converted into daily data by using simplified linear interpolation method. The evaluation criterion of CI for winter wheat in drought was revised according to the regions and growth stages by comparing of CI and daily soil moisture data,and standard cumulative indices of drought was established based on new indices. The evaluation model of yield loss in drought for winter wheat was established,considering to unit yield data of winter wheat. The results showed that the change of daily CI index was similar to that of soil moisture,and the corrected indices of 15 regions were quite different from the discrimination standards of meteorological drought composite indices(CI indices). Drought indices varied among regions,which was lower in western Henan,northern Shandong,southeast Shandong, Beijing,Tianjin and mid-eastern Henan,and higher in middle Shandong,northeast Hebei,middle Hebei and south Hebei. The evaluation models of yield loss in drought for winter wheat in 15 regions passed the 0. 05 significance test, and the standard cumulative index of drought was significantly correlated to winter wheat yield loss. It was significant between historical evaluation results and yield loss of drought( P 0. 05) in Beijing,Tianjin,middle Shanxi,south Shanxi,middle Shandong,southeast Shandong and west Henan. The evaluation models evaluated the yield loss in drought for winter wheat accurately,and the results could used for practice.