To investigate the short-term effects of biogas slurry fertilizer on the physicochemical properties of degraded grassland soil， this study investigated moderately degraded grasslands in Zhenglan Banner， Xilingol League. Four treatments were established： blank control （CK）， water control （W₀）， 50% diluted concentration of biogas slurry fertiliser （BS_50%）， and full concentration of biogas slurry fertiliser （BS_100%）. The application rate was 300 m³·ha^-1. The contents of nitrogen （N）， phosphorus pentoxide （P₂O₅） and potassium oxide （K₂O） in the biogas slurry are 0.11%， 0.07% and 0.09% respectively. Soil samples from 0~15 cm and 15~30 cm soil layers were collected to analyze their physical and chemical property indexes. The results showed that compared with CK， both BS_50% and BS_100% treatments significantly improved soil physical structure， with decreasing soil bulk density and increasing soil porosity. Applying biogas slurry fertilizer markedly enhanced soil physical and chemical properties and microbial activity. The contents of soil total nitrogen， available phosphorus and available potassium increased significantly by 14.50%-25.86%， 66.87%-204.06% and 30.26%-193.91%， respectively， while the contents of soil microbial biomass carbon and microbial biomass nitrogen increased significantly by 11.04%-18.39% and 12.47%-28.34%， respectively. This study revealed the short-term effects of biogas slurry fertilizer on the physicochemical properties of degraded grassland soils. It provides fundamental scientific evidence for restoring degraded grasslands and enhancing soil fertility， while also offering reference support for the resource utilization of biogas slurry fertilizer and the sustainable management of grassland ecosystems.

Biogas slurry fertilizer  /  Typical grassland  /  Moderately degraded grassland  /  Soil physical and chemical properties