The Coupling Relationship Of Soil Macro-Structure With Soil Erosion Resistance

The Loess Plateau is the most severely eroded, it is also the area which is the mostvulnerable of ecological environment in China. One of the important causes of soilerosion in the Loess Plateau is physical and chemical properties of loess susceptible toerosion. Soil structure greatly affected the composition of the soil aggregate structure,influenced the surface water infiltration rate, which affects the degree of soil erosionoccurred. Soil erosion resistance, including soil anti-scourbility and soil anti-erodibility.Soil anti-scourbility and soil anti-erodibility have both links and differences. In this paper,we studied the relationship of soil density, soil particle composition with soil erosionresistance, and we compared the difference of soil erosion resistance on different land usetypes through static water disintegration, flume scour, soil shearing experiments and soilinfiltration experiments. Finally, we explore coupling relationship that soil erodiblefactor-K value with the soil erosion resistance what we measured through used formulawhich was summed by predecessors and integrated the property data of soilmacro-structure, in order to clarify the soil erosion resistance of different structural,discover the optimal soil structure which have the best erosion resistance is extremelysignificant.(1) The influence is obvious that soil density to soil resistance erosion. The soilanti-scourbility gradually increased with increasing soil density. While soilanti-erodibility was not positively correlated with soil density as usual, soil densityincreases contribute to the enhancement of soil anti-erodibility when the soil density inless than1.27g/cm~3, soil anti-erodibility reduced with density greater than1.27g/cm~3. Inaddition, the shear strength increases gradually with the increasing of density and soilcohesion.(2) Soil erosion resistance is affected by soil particle composition significantly. Theresults show that: soil anti-scourbility, soil anti-erodibility and shear strength have apositive correlation with the soil clay content (<0.02mm). The more the content of clay is easy to form stable soil aggregate structure, thus soil erosion ability is stronger to resistthe outside energy.(3) We draw the following conclusions by studying soil anti-scourbility,anti-erodibility with the macro-structure of different land use types: woodland andgrassland significantly improved soil erosion resistance, and effectively control therunoff erosion caused by soil erosion. The difference of soil erosion resistance is due tothe different vegetation is not the same which improve the content of soil aggregates andother physical and chemical factors. Soil water-stable aggregate is an important factorwhich effect soil erosion resistance. Furthermore, woodland can increase soil aggregates,organic matter that material has cementation, thus reducing soil erosion anddisintegration, effectively enhance the soil erosion resistance.(4) By using the USLE model and the RUSLE2model to calculate the soilerodible factor-K, then fit and comparative analysis with soil erosion resistance. Thefollowing fitting results shown: analysis found that soil erodible factor-K in RUSLE2model better coupling with soil erosion resistance by comparing soil anti-scourbility, soilanti-erodibility, soil water stable index, USLE model, RUSLE2model. Therefore, soilerodible factor-K which calculated by USLE2model is more representative in region’ssoil erosion resistance.