Soil physicochemical properties and crusts regulate the soil infiltration capacity after land-use conversions from farmlands in semiarid areas

Abstract

Large scale land-use conversions played important role in regulating the process of soil infiltration, and thus changing soil moisture recharge. However, how the soil properties influence infiltration after farmland conversions remain unclear in the semiarid areas. This study used a double-ring infiltrometer to conduct infiltration experiments in soil surface and subsurface among land-uses on the Loess Plateau, to explore the mechanism of soil physicochemical properties and crusts on infiltration. The results showed that the revegetation lands effectively improved infiltration properties, while no significant differences were observed between the orchards and the farmlands. The loose soil structure, stable aggregates, higher organic matter and root mass density improved while soil crusts impeded infiltration capacity after farmland conversions. The impeding effect of the biocrusts presented throughout the infiltration process while physical crusts impeded infiltration only at the initial stage. Soil physical properties (i.e., bulk density, porosity, macroaggregate, texture, moisture), biochemical properties (i.e., soil organic matter, roots) and crusts were major factors in the variation of the surface (0–20 cm) infiltration properties, while subsurface (20–40 cm) infiltration were mainly influenced by soil physical properties. The deeper soils had a greater impact on steady infiltration rate than initial infiltration rate. Due to the plough pan in agricultural lands, the subsurface soil (20–40 cm) had a strong effect (42.1%) on the steady infiltration rate of the surface (0–20 cm) soil, even close to the surface (0–20 cm) soils (49.8%). These findings improve the comprehensive understanding of the soil hydrological processes after farmlands conversions in semiarid areas.