Abstract:

 The ricewheat double cropping in the Taihu Lake Basin was supposed to have originated from the Eastern Jin and Southern Dynasties（317～589）,and extended as a common planting practice for a long time in the ensuing dynasties.Our study showed that most of the time had witnessed no conspicuous seasonal conflicts in the double cropping in the region except for the following two periods:the Late Ming Dynasty and early Qing Dynasty period（1600～1700）,and the 19th century.In our study on the ricewheat double cropping history in association with climate changes,we discovered that the seasonal conflicts in this region were closely related to the climate variations,and the seasonal conflicts that appeared in the two historical periods were both caused by the climate cooling rather than by social factors such as population and crop variety.The two historical periods concerned had experienced the coolest time in the history