Risk assessment model of drought-caused winter wheat yield loss and its applications in Henan Province

As a major agrometeorological disaster of winter wheat in Henan, drought is a big contributing factor to the steady rise of the yield. To make risk assessment of the drought-caused yield decline is of much significance to rational choice of culvars and putting forth measures against drought loss. Based on interannual meteorological and yield records, analysis is undertaken of yearly drought probability, percentage yield decline and yield coefficient of variation, whereupon is constructed a model for comprehensive risk assessment of wheat yield and regionalized is the risk happening. Evidence suggests that the indices of the risk assessment range over 1.23 similar to 4.88, with the high-value zones making up 12.5%, distributed mainly in eastern, and northeastern Henan, the middle-value zones accounting for 36.5% in southwest, southeast, eastern, northeast and northwest Henan and the low-value zones (51.0%) in the extensive region, with Lushi - Xiangcheng (Beijing to Guangzhou railway in Henan) as the axis line in the east - west (south - north) Henan province.