| The results of analysis of temperature and precipitation on arid and semi\|arid Huanxian County in the past 38 years (1971～2008) show that there was a clear tendency of warming and drying there, and the annual average temperature increased with a rate of 0.0385℃/a, much higher than that of the nationwide rate of 0.004℃/a in the past 40 years.The maximum temperature increase occurred in the 1980s and 1990s.For seasonal changes, we found significant warming in spring and winter, but slow warming in summer and autumn.The annual precipitation showed a slight decreasing trend, while the monthly precipitation varied, which increased significantly in June and September while decreased remarkably in July and November, and maintained normal or reduced slightly in other months.The precipitation increased from 1970s to 1980s, decreased from 1980s to 1990s, and increased again from 1990s to 2000.Since 1980s, the precipitation in spring decreased obviously and resulted in spring drought, while it in other three seasons showed no uniform changing tendency, increasing or decreasing in different period of years.In the past 26 years (1983～2008) , 0～100 cm soil water storage showed an increasing trend, with an annual growth rate of 0.5586 mm/a.Among them, it increased in spring and fall, with the increasing rate of 0.941 mm/a and 0.5164 mm/a respectively, while it decreased in summer.No matter in dry years or wet years, or in different period of years, the minimum amount of soil water storage always appeared in June when the crops grew vigorously, while the maximum amount always appeared in fall, rather than in the wettest summer.The warming and drying tendency of climate had obvious impact on 0～30 cm soil water storage, which varied much in different years. |