基于RWEQ模型的土壤风蚀模数影响因素研究

Study on Influencing Factors of Soil Wind Erosion Modulus Based on RWEQ Model

RWEQ模型是定量研究土壤风蚀的关键模型,为深刻分析该模型在建模过程中各引入变量与土壤风蚀的关系,以土壤最大转移容量(Qmax)为描述变量,探究植被盖度、土壤粘粒含量与Qmax的关系,对植被盖度、土壤粘粒含量分段赋值,产生9898组变量组合,计算了气象因子为17、可蚀性因子为0.456、土壤粗糙因子为0.68、有机质含量为2%前提条件下的Qmax值,分析了各种组合条件下三者的关系,结果表明:1) Qmax值与植被盖度存在较明显的负相关关系,且40%植被盖度是抑制风蚀作用的重要节点盖度,在达到此盖度前植被具有剧烈的抗风蚀作用;2) 与上述方法相同,土壤粘粒含量也与Qmax值呈负相关关系,且土壤粘粒含量阈值达到30%后抗风蚀作用明显减弱;3) RWEQ模型中各因子对于Qmax值的耦合作用、以及不同分蚀阶段的主导因素不同。低阈值阶段,土壤粘粒含量对于Qmax值的影响较明显;高阈值阶段,植被盖度又对Qmax值的影响较为明显。

The RWEQ model is a key model for the quantitative study of soil wind erosion. In order to deeply analyze the relationship between each introduced variable and soil wind erosion in the modelling process of this model, the maximum soil transfer capacity (Qmax) was used as the descriptive variable to investigate the relationship between vegetation cover, soil clay content and Qmax. 9898 sets of variable combinations were generated by assigning values to vegetation cover and soil clay content in segments, and calculating the Qmax values under the preconditions of meteorological factor of 17, erodibility factor of 0.456, soil roughness factor of 0.68 and organic matter content of 2%. The relationship between the three is analysed for various combinations of conditions. The results show that: 1) There is a significant negative correlation between Qmax and vegetation cover, and 40% vegetation cover is an important node cover to inhibit wind erosion, and vegetation has strong resistance to wind erosion before reaching this cover;2) As in the above method, the soil clay content is also negatively correlated with the Qmax value, and the wind erosion resistance is significantly weakened after the soil clay content threshold reaches 30%;3) The coupling effect of each factor in the RWEQ model on the Qmax value, as well as the dominant factors in different erosion stages, is different. In the low threshold stage, the influence of soil clay content on Qmax values is more obvious;in the high threshold stage, the influence of vegetation cover on Qmax values is more obvious.