Vegetation restoration affects soil hydrological processes in typical natural and planted forests on the Loess Plateau
Xiru Liu, Tianjiao Feng, Yufei Zhang, Yabo Liu, Ping Wang
Abstract
Globally, vegetation restoration has long been a crucial method for ecohydrological remediation in fragile ecosystems. However, a more comprehensive understanding of how vegetation attributes and environmental factors collectively influence hydrological processes is essential for ensuring the practicability and attainability of sustainable vegetation restoration. This study focused on four typical vegetation restoration types in Caijiachuan National Forest Park (36°14′27″-36°18′23″N, 110°39′45″-110°47′45″E), Ji County, Shanxi Province, on the Loess Plateau: Pinus tabuliformis planted forest, Platycladus orientalis planted forest, Robinia pseudoacacia planted forest, and natural secondary forest. From 2017 to 2022, the study investigated soil properties, soil water dynamics in the 0–200 cm layer, surface soil infiltration, understory attributes, and water-holding capacity. The findings were as follows: (1) Natural secondary forests improve water holding capacity in deep soil layers compared with planted forests. (2) Soil infiltration capacity was significantly higher in the natural secondary forest than planted forests ( p < 0.05). (3) An increase in soil organic matter, total porosity, silt, and a decrease in soil bulk density and soil volumetric water content effectively improved soil infiltration capacity. (4) After near-natural vegetation restoration, vegetation attributes significantly improved soil properties ( p < 0.01), directly impacting soil hydrological processes ( p < 0.001, R 2 = 0.89) and soil water holding capacity ( p < 0.01, R 2 = 0.79). The structural equation model indicated that vegetation restoration indirectly affects soil hydrological processes by directly altering soil properties. Therefore, considering the conditions in arid and semiarid areas like the Loess Plateau, natural secondary forests should be prioritized in vegetation restoration projects. These effects should also be factored into the evaluation of water resource utilization and allocation.