A Study on The Relationship between the Index of Spring Drought and Winter Wheat Output in South Gansu and its Prediction

Drought is the main disastrous element influencing winter wheat output in South Gansu.Based on agricultural meteorological factors during the critical period of winter wheat growth,the index of spring drought was adopted.After analyzing annual change of the index and its effect on winter wheat output,according to the prediction model of the mean generating function,the index and the winter wheat output have been predicted.The result of prediction is accurate after tests from 1999 to 2000.