关键词: 茶园土壤, 茶园土壤, 茶叶, 土壤养分, 重金属, 污染指数

Abstract: The paper aims to comprehensively analyze the drought characteristics of Chang Tang national nature reserve region of Tibet during 1971-2017 and effectively response to drought risk and ecological environmental protection. The authors obtained the spatial-temporal drought distribution characteristics of Chang Tang national nature reserve region by using daily precipitation data of 5 meteorological stations from 1971 to 2017 with drought evaluation indicator as the Consecutive Dry Days (CDD) and statistical methods like linear regression, Mann-Kendall test and rescaled range analysis (R/S analysis) et al. The results shows that: On a multi-year average, the CDD ofSeachSstation were 78-162 days in nature reserve region, and the distribution was decreasing from eastern to western, as well as the probability of more CDD was 51.1%. The CDD exhibited decreasing trend with a rate of 3.4 d/10a in nature reserve region during the recent 47 years, and it increasing trend since the 1990s. On the decadal scale, the CDD was more in the 1970s and normal during 1980s to 2100s, in addition the CDD was the highest in the 1970s during the past 47 years. Also, the CDD were more anomalous years in the 1990s with a frequency of 2 times, whereas less anomalous years not occurred. According to the Mann-Kendall test, the abrupt change of CDD occurred in 1980, indicating a change from the more period to the less one. The results of R/S analysis showed that changes of CDD had the persistence with a Hurst index of larger than 0.5 in nature reserve, which indicates that it will assume continuous decrease in future.