Saturated soil hydraulic conductivity and its determinants in grassland with varying levels of desertification in Northwest Liaoning Province

【Background and Objective】 The arid and semi-arid regions in Northwest Liaoning Province are characterized by low precipitation and high evaporation, leading to desertification, soil erosion and degradation. This paper presents the results of an experimental study on variation and determinants of saturated hydraulic conductivity of soils in these regions. 【Method】 This study was conducted in grasslands exhibiting various levels of desertification. We measured the saturated hydraulic conductivity of soils at different depths, along with various influencing factors across different regions. 【Result】 The impact of desertification on soil hydraulic conductivity varied with soil depth. In the top 0-30 cm soil, the saturated hydraulic conductivity of soil in non-deserted, slightly deserted, moderately deserted, and severely deserted regions was 2.46 mm/min, 5.57 mm/min, 8.72 mm/min and 9.04 mm/min, respectively. The impact of desertification on hydraulic conductivity of soil in the 30-70 cm layer is similar, with the saturated soil hydraulic conductivity in the non-deserted regions being 30% of that in the severely deserted region. In the 70-100 cm layer, the saturated soil hydraulic conductivity in different regions was ranked in the order of non-deserted < slightly deserted < severely deserted < moderately deserted, with the saturated soil hydraulic conductivity in the non-deserted region being 40% of that in the moderately deserted region. Saturated soil hydraulic conductivity was negatively correlated with soil phosphatase and positively correlated with sand content, bulk density, and porosity of non-capillary pores. Soil saturated hydraulic conductivity linearly decreases with soil desertification in y=13.13x-31.80, which could explain 98.70% of the variation in the hydraulic conductivity. It was also found that, regardless of the level of desertification, soil hydraulic conductivity tended to increase with soil depth and vegetation coverage. 【Conclusions】 The saturated hydraulic conductivity of soils in the grasslands in the northern Liaoning Province varies with both soil depth and the degree of desertification. Key factors influencing this variation include sand content, phosphatase content, bulk soil density, and presence of large non-capillary pores.