澜沧江流域生态系统土壤保持功能及其空间分布

Ecosystem's soil conservation function and its spatial distribution in Lancang River Basin,Southwest China

基于改进的通用土壤流失方程对澜沧江流域生态系统的土壤保持功能及其空间分布特征进行分析.结果表明:澜沧江流域是我国生态系统土壤保持能力最高的区域之一,其年均土壤保持量为2.36×1010t.a-1,单位面积土壤保持量为1453.72t.hm-2;土壤N、P、K元素保持量分别为5.74×107、3.07×107和3.75×108t.a-1,从上游至下游呈递增趋势.各类生态系统中,森林生态系统土壤保持能力最高,草地和农田其次,荒漠生态系统最差.不同生态系统的土壤保持能力均随植被盖度的增加呈线性增长.澜沧江流域生态系统的植被盖度每增加10%,其土壤保持能力平均增加35.3%.在对该区域生态系统进行保护的基础上,因地制宜地合理增加植被盖度对防治土壤侵蚀、保持土壤养分可以起到良好效果.

Based on the RUSLE model,this paper analyzed the ecosystem＇s soil conservation function and its spatial distribution in Lancang River Basin.This Basin could be one of the regions having the highest ecosystem＇s soil conservation capability in China,with an annual ecosystem＇s soil conservation amount being 2.36×1010 t·a-1 and the soil conservation amount per unit area being 1453.72 t·a-1 per hectare.The total amounts of the N,P,and K conserved in soils were 5.74×107,3.07×107,and 3.75×108 t·a-1,respectively,and presented an increasing trend from upstream to downstream.Among the ecosystems in the Basin,forest ecosystem had the highest soil conservation capability,followed by grassland and farmland,while desert ecosystem had the lowest one.The soil conservation capability of the ecosystems was linearly increased with the increase of vegetation coverage.Averagely,a 10% increment in the vegetation coverage could result in a 35.3% increment in soil conservation capability.To rationally increase the vegetation coverage by reliable ecosystem management based on local conditions would make good effect in preventing soil erosion and maintaining soil nutrients in the Basin.