三峡库区王家桥小流域土壤侵蚀因子初步研究

通过对王家桥小流域土壤，降雨，植被和地形等因子的分析，探讨了土壤抗侵蚀性能，分析了坡面侵蚀与各影响因子间的关系，建立了基于降雨基础上的全流域输沙幂函数回归方程。结果表明，本地区土壤因具有较强的渗透性，抗冲，抗蚀和抗剪切破坏的能力，而使其保持较小的可侵蚀性；坡面侵蚀中的主要影响因素是雨强和径流量（或降雨量）的大小；流域内土壤侵蚀的形式主要表现为暴雨作用下的重力侵蚀，在影响土壤侵蚀的诸多因子中降雨是关键性的，它的强度和年分布对年侵蚀模数的大小具有决定性作用。同时，通过分析各种雨强（平均雨强，最大雨强，最大15分钟雨强，最大30分钟雨强，最大60分钟雨强）对土壤侵蚀量的影响，结果表明，虽然最大60分钟雨强具有最优相关性，但在多元回归方程中，采用最大30分钟雨强回归效果最佳。

PRIMARY STUDY ON SOIL EROSION FACTORS OF THE WANGJIAQIAO WATERSHED IN THREE GORGES RESERVOIR AREA

Through analyzing the various factors from soil, precipitation,vegetation to topographer of the small Wangjiaqiao water-shed, characteristics of the soil anti-erosion were discussed.Connections between slope erosion and relative factors were analyzed and power-regression equations of the transporting-sand about the watershed were developed on the basis of precipitation . The results showed that soil in the region was not liable to erosion owing to its sharp infiltration and intense capacities in anti-rinse, anti-erosion and anti-shear.Precipitation-intensity(PI) and precipitation were the key factors in the slope erosion.The soil-erosion model in the watershed was whelmed with the gravity erosion when rainstorm happened.Precipitation was highly influential to soil erosion, which intensity and annual distribution was crucial to annual erosion modulus. Moreover, based on the results of the linear correlation between soil-erosion amount and all kinds of PI including avg. PI, max. PI, max. PI 15, max. PI 30,and max. PI 60, it is shown that the max. PI 30 was optimal in the power-regression equations, although the max. PI 60 is the best linear correlation between soil-erosion amount and all kinds of PI.