川中丘陵紫色土区农业型小流域土地利用结构与土壤流失关系

Relationship Between Land Use Structure and Soil Losses Watershed of Central Hill Region of Sichuan Basin

以农作型小流域为研究对象,建立小流域土壤侵蚀模数、轻度以上侵蚀土地占地率与平耕地、坡耕地、有林地、其它林地、荒草地、其它用地占地率无截距模型,以及小流域土壤侵蚀模数与不同侵蚀强度土地占地率无截距多元回归模型,分析不同类型土地的侵蚀模数、土壤流失率、土壤流失比、土壤流失面积比,不同侵蚀强度土地侵蚀模数、土壤流失比。结果表明:①无明显侵蚀、轻度侵蚀、中度侵蚀、强度及其以上侵蚀土地土壤侵蚀模数分别为:-397.78t/km2·a、1639.95t/km2·a、5000.00t/km2·a、9119.12t/km·2a,土壤流失比分别为:-7%、6%、34%、67%,在不同小流域变幅为:-3%--23%、0%-21%、8%-100%、11%-98%,有80%的小流域强度侵蚀土地是土壤流失的主要源地,有20%的小流域土壤流失主要发生在中度侵蚀土地;②平耕地、坡耕地、有林地、其它林地、荒草地、土壤侵蚀模数分别为:458.27t/km2·a、6410.8t/km2·a、-2083.89t/km2·a、2668.43t/km2·a、6639.33t/km2·a、-759.6t/km2·a;土壤流失比分别为:-6%、89%、-4%、11%、12%、-3%,流失面积比为1%、72%、0%、18%、9%、0%,水土流失的首要用地类型是坡耕地,平耕地、有林地、其他用地对土壤流失起到抑制作用。

In This paper, the Agro-type watershed as study object, no-intercept model was constructed between soil erosion modulus, slight erosion land ratio and fiat cultivated land, hillside cultivated land, forest land, other forest land, wild land, other land. Model between soil erosion modulus and percentage of land area of different soil erosion intensity was Constructed also. And different land type erosion modulus, soil losses percentage, soil losses ratio, soil losses area ratio and different soil erosion intensity modulus are analyzed. The results showed that： （1）Soil erosion modulus reached -397.78t/km2·a, 1639.95t/km2·a, 5000.00t/km2·a, 9119.12t/km2·a at slight erosion land, light erosion land, moderate erosion land and above strong erosion land, the soil erosion percentage reached -7%, 6%, 34%, 67%. Above strong erosion land is the main loss land at 80% watershed, and moderate erosion land is the main source of soil loss at 20% watershed. （2） Soil erosion modulus reached 458.27t/km2·a, 6410.8t/km2·a, -2083.89t/km2·a, 2668.43t/km2·a, 6639.33 t/km2·a,-759.6 t/km2·a at fiat cultivated land, hillside cultivated land, forest land, other forest land, wild land, other land; the soil loss percentage reached -6%, 89% ,-4%, 11%, 12%,-3% separately; the soil loss area percentage reached 1%, 72%, 0%, 18%, 9% and 0%. Slope cultivated land is the main land use type of soil loss, fiat cultivated land, forest land and other land can control soil losses.