Effect of vegetation restoration on soil infiltration at gully heads in the loess plateau Pisha sandstone region

Abstract

Soil infiltration is of great significance for assessing the potential and stability of vegetation restoration in arid and semi-arid regions. However, the mechanisms by which different types of vegetation influence soil infiltration at gully heads in Pisha sandstone region remain unclear. Therefore, the study focuses on the typical small watershed of Getuodian in the Pisha sandstone region of the loess plateau. It measures the soil stable infiltration rate (SIR) and soil properties at gully heads under five vegetation types—Pinus tabuliformis (PT) and Prunus sibirica (PS) artificial arbour forest, Hippophae rhamnoides (HR) and Caragana korshinskii (CKS) artificial shrubland forest, and natural grassland (NG)—Based on the in-situ double-ring infiltration method and laboratory analysis. The SIR consistently follows the trend: Arbor forest > shrub forest > natural grassland. Among the arbor plots, the stable infiltration rate of PT is higher, at 2.81 mm min⁻¹, whereas in the shrub plots, the CKS is higher, at 1.48 mm min⁻¹. The soil organic carbon (SOC), the ratio of macroaggregates with particle size greater than 0.25 mm (R), aggregate stability (as measured by the mean weight diameter (MWD) and geometric mean diameter (GMD)), and clay had the strongest effect on the SIR. The five factors in total contributed 87.45% to the SIR, which was significantly higher than that of individual factors. The SOC indirectly influences the SIR by promoting the formation of macroaggregates, enhancing aggregate stability, and subsequently improving clay content. Moreover, the empirical model established based on the relationships between these factors and the SIR was able to accurately estimate the SIR (R² = 0.982). The findings provide a valuable reference for assessing hydrological processes in the loess plateau.