Spatial Variation Characteristics and Influencing Factors of Black Soil Quality in Typical Water-Eroded Sloping Cropland

Abstract

[Objective] This study aimed to clarity the role of sedimentation and erosion in shaping the spatial pattern of soil quality in black soil slope croplands. [Methods] Taking the sloping farmland in typical water-eroded areas in northeast China as the research object, we used the soil attributes of 110 sample points and the soil quality index (SQI) index based on the minimum data set to evaluate the spatial differentiation characteristics of soil quality at the slope scale, while the effects of slope gradient, slope position, and soil depth were determined using generalized linear models (GLMs). [Results] (1) Opposing patterns of soil nutrient content and spatial characteristics were observed between the surface and subsurface layers in sloping croplands. Most nutrient indicators exhibited significantly higher content in the tillage layer compared to the subsurface layer. However, the surface layer showed lower spatial heterogeneity and weaker correlation with related physicochemical indexes comparing with the subsurface layer (p0.05). (3) Soil depth, slope position, and slope gradient emerged as key factors influencing the variability of SQI in slope croplands. The GLM results demonstrated that, for the same soil horizon, slope, aspect, and their interactions explained over 95% variation in SQI. Among them, the explanatory degree of slope position was 68%, and that of slope gradient was 22%. Considering the factor of soil depth, the explanatory degrees of soil depth, slope position, and slope gradient on the variation of SQI in the range of 0—40 cm were 39%, 31%, and 10%, respectively. [Conclusion] The combined method of SQI and GLM was used to clarify the shaping role of the erosion-sedimentation process in the spatial differentiation of black soil quality in sloping cropland, and the research results can provide technical support for the evaluation and management of the quality of eroded and degraded black soil in typical water-eroded areas.

Keywords

• soil erosion
• sedimentation
• topographic factors
• soil quality index
• generalized linear model