Abstract:Based on the long-term meteorologic data from 1960 to 2001 and our relevant researches from 1990 to 2001 in Taoyuan County(28°24′~29°24′N,110°51′~111°36′E,4458.4 km~2)of Hunan,the seasonal drought problems in the red soil hilly region of the middle subtropical zone of China were studied. The primary reasons for seasonal drought are as follows:(1)The distribution of precipitation is uneven though the amount of it exceeded 1400 mm per year,of which (45.9%) occurred from March to June and (27.4%) from July to...