南方红壤区水土流失动态演变趋势分析

利用水利部3次土壤侵蚀遥感调查数据,结合实地抽样调查,分析了南方红壤区水土流失演变态势:南方8省区水土流失面积从20世纪50年代初的10.5万km2 增加到2002年的19.6万km2,净增加了9.1万km2,1986年前呈增加趋势,之后呈逐步减少的趋势,到1996年实现了治理大于破坏的历史性转变.不同时段水土流失演变的趋势和增减速率各异,且随着时间的推移增减幅度在减小.抽样结果显示,2002-2005 年的3年间,南方8省考察区水土流失面积共减少约4500 km2,年均减幅为 1.2 个百分点,按此速度估算,南方8省区19.6万km2水土流失面积需要130年以上的治理时间,因此需要进一步加大治理力度.

Changes of soil and water loss in red soil region of Southern China

The soil erosion data of soil erosion at different historical times were used in this paper to analyze the changes of soil and water loss in red soil region of southern China. The soil erosion area of all the eight southern provinces increased from the early 1950s' 1.05×105 km2 to 2002's 1.9×105 km2. Soil erosion area increased before 1986, and decreased gradually after 1986 in the recent 50 years, and in 1996 it reached the turning point of soil loss control. The changing tendency and rate of soil erosion were various in different periods, the range became smaller gradually. Field survey showed that from 2000 to 2005 the area of soil and water loss decreased by 4.5×103 km2 with an annual decreasing rate of 1.2%, which means at least 130 years needed to finish the control task of the current 1.96×105 km2 eroded area.