National Society Science Foundation of China (Grant No. 08BZZ031); National Nature Science Foundation of China (Grant No.40471053, Grant No. 40501077);Key Lab Foundation of Shaanxi (Grant No. 04JS39);Key Foundation of Baoji University of Arts & Sciences (Grant No.ZK06111).
In this paper, the index systems of the agricultural drought and decrease percentage of grain crop are established. The trend and influence of drought in the region is analyzed based on the 50 years (1951-2000) stat...