[Characteristics and adaption of seasonal drought in southern China under the background of global climate change. II. Spatiotemporal characteristics of drought for wintering grain- and oil crops based on crop water deficit index].

In recent years, seasonal drought occurs frequently in southern China, giving severe impact on the production of local wintering crops. Based on the 1959-2009 meteorological data from 268 meteorological stations in southern China, and by using crop water deficit index (CWDI) as agricultural drought index, this paper analyzed the spatiotemporal characteristics of drought for winter wheat and rapeseed. The results showed that in southern China, drought happened more frequently in Southwest China, north Huaihe basin, and parts of South China during the developmental stages of wintering crops. In the mid-lower Yangtze basin, the intensity and extent of drought increased during the mid-late developmental stages of winter wheat, and became much heavier at its later developmental stages. For rapeseed, the intensity and extent of drought increased during the developmental stage before winter and the late developmental stages. In southwest part, the intensity and extent of drought increased significantly during the developmental stage before winter for winter wheat and rapeseed. Since the early 1990s, the intensity and extent of drought in southern China increased during the mid-late developmental stages of wintering crops.