Abstract:

Drought is one of the main hazards for winter wheat production in Hebei Province. Aiming at the service demand of monitoring the winter wheat drought in Hebei Province, in order to objectively identify and monitor the occurrence and development of winter wheat drought, we designed the wheat drought monitoring model. Based on the analysis of the limitations of single drought index, the soil relative moisture index, crop water deficit departure index and precipitation departure index were applied in the model of winter wheat drought monitoring, because they could reflect the drought of soil, crop and atmospheric respectively. The weight coefficient of the three drought indexes were defined by analytic hierarchy method. Data were selected to analyze the accuracy of the composite index in characterizing winter wheat drought, while those data came from eight representative stations in Tangshan, Zhuozhou, Dingzhou, Huanghua, Shenxian, Luancheng, Nancheng and Feixiang in Hebei Province from 1981 to 2010. The results showed that: first, while there was no drought condition, the single index and composite index can reflect the situation, and the case was 17.6% of the total. Second, when the drought situation existed, composite drought index was able to reflect both the situation of irrigation, while the precipitation departure index could not reflect, and the situation of prophase drought, thus it could reflect the drought situation, and the case was 67.6% of the total. Negative precipitation departure index and crop water deficit departure index were too sensitive to precipitation, and little precipitation would cover the real drought situation, as a result, they could not truly reflect the drought situation. The composite index could not only reflect the influence of precipitation on drought, but also reflect the influence degree, and the case was 17.6% of the total.