原状土冲刷法与人工模拟降雨法研究土壤抗冲性对比分析

Comparison Analysis on Soin Anti-scourability Between Undisturbed Sampling and Artificial Rainfall Plot

在相同条件下，对比研究了人工模拟降雨小区（２ｍ×５ｍ）和用大型抗冲槽（１０ｃｍ×２０ｃｍ×１０ｃｍ）测定的土壤侵蚀量、产沙过程及抗冲性异同。结果表明在０．６５ｍｍ／ｍｉｎ和０．８４ｍｍ／ｍｉｎ雨强１５ｍｉｎ冲刷时间内，大型抗冲槽侵蚀模数为人工降雨小区的２００～４００倍，但二者存在一定量关系。抗冲槽侵蚀过程与人工降雨小区呈相反趋势。径流深为小区的５０～１４５倍，单位径流深引起的侵蚀模数为小区的５～７倍（裸地）和１．８～４．５倍（人工草地）。本文分析了二者侵蚀过程差异及形成原因。研究还发现大型抗冲槽与小型抗冲槽所测侵蚀模数存在定量关系，在一定范围内小型槽可以取代大型槽进行抗冲性测定。

The soil loss. sediment yield and process as wellas soilanti-scourability were tested onfield artificial funoff plot and undisturbed soil sampling(10cm×20cm×10cm)under the sameconditions.The result showed that soil sample washing method was 200～400 times of soil lossthan in the runoff plot in 15 minutes with rainfall of 0.65 and 0.84 mm/min. The erosion pro-cess in soil sample washing was different from in runoff plot.The runoff depth in former was 50～150 times and erosion modulus was 5～7times (bare land)and 1.8～4.5 times (pasture)of inrunoff plot.The reason of such difference was analysised.It was also found that there exited re-lation of sediment yield between samples of large size(10cm×20cm×10cm )and small size(3.5cm×20cm ×4cm).and sediment yield in former can be estimated by small one.