Study on Drought Indicies and Loss Assessment for Winter Wheat in North China

摘要

Drought is a principal agrometeorological disaster to winter wheat zones in North China. From the correlation of wheat yield to rainfall the drought indices are determined that correspond to varying levels of severities on an agricultural basis. In wheat growing season, when rainfall displays its negative anomalies of < 15, 15-35, 36-55 and > 55%, there occurs a slight, moderate, heavy and extreme drought, leading to yield drop by < 10, 10-20, 21-30 and > 30%, respectively. The economic loss consists of yield reduction and drought-fighting input like irrigation. A drought-caused loss model is presented from historical meteorological and wheat yield datasets, with which to make the distribution of economic losses in the last 30 years over the province of Henan. Evidence suggests that in years of heavy droughts the loss was between 450 to 675 ( < 250) RMB yuans per hectare in the NE (West - SW) segment of the province.