Analysis of tendency on 0 ℃ accumulated temperature during last 30 years inHainan area of Qinghai Province

The accumulated temperature is one of important characteristics on the crop and forage production. Analyzing changes of the accumulated temperature could benefit to animal production as well. This study analyzed the changes of 0 ℃ year accumulated temperature and its influence on production of crops and forages using the data obtained from the weather stations at 5 counties in Hainan Tibetan Autonomous Prefecture, Qinghai Province. The results indicated that during last near 30 years the growing periods of major crops and forages were shortened, while the initial growing period were forward. This was because in recent ten years the average temperature and regional 0 ℃ year accumulated temperature increased and thermal condition was sufficient for the growth of crops and forages, which provide a basis for the timely adjustment of agricultural structure in the region.