Soil Resistance and Its Influencing Factors Under Different Land Use Types in the Black Soil Region of Northeast China

Abstract

[Objective] Soil resistance reflects the characteristics of soil to mitigate erosion and is quantified by rill erodibility (Kr) and critical shear stress (τc). To investigate the difference of soil resistance and its main controlling factors under different land use types through the flume scouring test, which provided a theoretical basis for revealing the dynamic mechanism of soil erosion in Northeast black soil area. [Methods] Seven typical land use types were selected in the Hebei small watershed of Heshan farm, located in Nenjiang city of Heilongjiang Province. Kr and τc were determined using the measured soil detachment capacity by scouring test in a large hydraulic flume. The dominant factors influencing soil resistance were determined by correlation analysis and partial least square regression. [Results] (1) The estimated Kr varied from 0.003 to 0.372 s/m among different land use types. Kr of road was the highest. Compared to cropland, Kr of grassland, transverse forest belt, woodland, longitudinal forest belt, and shrub land decreased by 94.00%, 86.20%, 84.00%, 83.60%, and 71.60%. The fitted τc ranged from 4.84 and 13.85 Pa. Cropland and road had lowest τc (4.84 and 9.80 Pa). The differences in τc were not significant between other land use types and were greater than 10.00 Pa. (2) Correlation analysis showed that Kr was significantly correlated with clay content, aggregate stability and organic matter content (p<0.01), and sand content, soil cohesion, root mass density and litter density mixed within topsoil layer negatively (p<0.05). It was significantly correlated with silt content positively (p<0.01). τc was significantly related to silt content negatively (p<0.01). It was significantly correlation with sand content and topsoil litter density (p<0.01), and organic matter content and root mass density positively (p<0.05). (3) The results of PLSR analysis demonstrated that the dominant factors influencing Kr were soil clay content, silt content, aggregate stability, root mass density, organic matter content and litter density mixed within topsoil layer. The key factors affecting τc were soil organic matter content, litter density mixed within topsoil layer, silt content and root mass density. [Conclusion] Land use type significantly affects soil resistance. Grassland is most effective at mitigating erosion and is critical for reducing erosion on cropland. Root mass density, litter density, soil texture, aggregate stability and organic matter content are key factors influencing soil resistance. The results of the study provide a theoretical basis for understanding the mechanism of land use type impacting soil erosion dynamics and land use optimization in the black soil area.

Keywords

• land use change
• soil detachment capacity
• soil resistance
• rill erodibility
• critical shear stress