Research of Drought Risk Assessment for Winter Wheat in Northern China

This paper carried out the drought risk assessment and zonation of winter wheat in northern China based on the impact of drought on crop yield by focusing on China's Grain Producing Areas. The adaptability of drought indices including MCI,CWDIa,CI,Paand Mawere compared,and on this basis the drought risk index was determined. Many critical environmental and agricultural factors were selected to analyze the background and drought vulnerability in winter wheat region of northern China,such as topography,soil type,soil available water holding capacity,drainage network,irrigation,precipitation,aridity index,cultivated land area,grain planting area,water sensitive coefficient in major growth period,and historical yield,etc. The relationship between the drought risk index and the yield reduction rate of winter wheat was built,the drought risk index was graded by using the yield reduction rate of winter wheat,and then the frequencies beyond the different drought disaster thresholds were calculated. Based on that,the different levels of drought frequency during the whole growth period and six critical growth stages were analyzed. At last,a comprehensive regional drought risk evaluation model and division method were established combining with the risk of drought,drought vulnerability of different backgrounds and regions. The results showed that MCI could well reflect the characteristics of drought in winter wheat region of northern China,which was determined as the drought risk index. The drought risk in north- central region of winter wheat area was higher than that in other regions of northern China,so the capacity of drought management should be strengthened. In comparison,the drought risk in southern region was lower,including Jiangsu,Anhui and southeastern of He'nan. Drought disaster risk assessment models of winter wheat in different growth stages could be applied to the real- time drought disaster risk assessment operation system.