Soil erodibility, microbial biomass, and physical–chemical property changes during long‐term natural vegetation restoration: a case study in the Loess Plateau, China

Abstract

AbstractSoil erodibility (Kfactor) is an important index for measuring soil susceptibility to water erosion, and an essential parameter that is needed for the prediction of soil erosion. Field investigation and laboratory analysis were conducted to study the changes of soil characteristics during long‐term vegetation restoration in the hilly gullied loess area. The soil erodibilityKvalues were calculated using the EPIC model and the physico‐chemical properties as well as microbial characteristics were evaluated along a chronosequence of natural vegetation recovery (0–50 years) in abandoned land in the Zhifanggou Watershed of Ansai County, northwestern Shaanxi Province, China. The results showed that natural vegetation recovery following abandonment resulted in improvement of the soil properties and structure and these improving effects were closely related to the date of abandonment. Specifically, theKvalue of the surface layer (0–20 cm) was significantly reduced with time, while the total organic carbon, total nitrogen and soil microbial biomass C, microbial N and microbial P and the water‐stable aggregate increased quickly. During the first 10 years of abandonment, these changes occurred relatively quickly due to a significant increase in soil organic matter, after which they gradually fluctuated for approximately 20 years, reaching their uttermost or minimum levels finally. However, these values differed greatly underPlatycladus orientalisforest, which suggests that soil rehabilitation is a long‐term task that requires several generations to complete.