Abstract:
Objective The aim was to clarify the influence mechanism of different grass and shrub composite plots on soil detachmentrate.
Method Typical grass-shrub sample plots were selected for this experiment: Caragana korshinskii, Caragana korshinskii and Agropyron cristatum, and Caragana korshinskii and Artemisia gmelinii. The distribution characteristics of soil detachment rates and their influencing factors were investigated in the different grass-shrub sample sites at a fixed flow and slope.
Result The three main effects of sample plot type, distance, and soil depth have significant effects on soil detachment rate (P < 0.05). The rate of soil detachment at the base of the shrubs was higher than that at 50 cm from the base of the shrubs in different sample plots. Importance analysis based on the Random Forest algorithm showed that among the root and soil indicators affecting soil detachment capacity, the highest relative importance was given to root length density and greater than 0.25 mm soil aggregate, respectively. The functional relationship between root length density, soil aggregate and soil detachment capacity could be expressed by Dc=(RLD*Aga)1/b, and R2 is above 0.72 in different sample plots. On the whole, the lowest soil separation rate in different areas was Caragana korshinskii and Artemisia gmelinii sample plots.
Conclusion In this study, root length density and aggregates larger than 0.25 mm are the main factors affecting soil detachment. This study has implications for revealing the mechanisms by root systems and soil properties affecting soil detachment at different sample plots.
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