青藏高原不同类型草地土壤可蚀性对放牧干扰的响应OA

[Objective]To explore the variation characteristics of soil erodibility across different types of grasslands on the Qinghai-Xizang Plateau under different degrees of disturbance,and to provide a scientific basis for refined management of grassland ecological restoration in the region.[Method]Three types of grasslands(warm grassland,alpine grassland and alpine meadow)in the Qinghai-Xizang Plateau were selected as the research objects.Soil samples were collected from four disturbance levels:non-disturbance(CK),mild disturbance(LD),moderate disturbance(MD),and severe disturbance(HD).The fractal dimension(Dv),multifractal theory(Dm),and erodibility factor(K)of microaggregates were calculated to quantify the change in soil erodibility.[Results](1)Soil erodibility of the three grasslands changed significantly after different degrees of grazing disturbance.The soil erodibility of alpine grassland increased significantly under severe disturbance(p<0.05),while that of warm grassland and alpine meadow decreased significantly(p<0.05).(2)Disturbance altered soil organic carbon content,which in turn affected soil erodibility.(3)In the 10-30 cm soil layer(10-20 cm and 20-30 cm),lower organic matter content and poor aggregate stability led to higher sensitivity of K and Dv values to disturbance.[Conclusion]Disturbance affects soil erodibility by altering soil organic carbon content,and different types of grasslands respond significantly differently to disturbance due to variations in soil properties and vegetation characteristics.In alpine grasslands,where vegetation cover is low,the organic carbon pool is poor,and soil structure is relatively loose,grazing further destroys soil aggregates,making fine particles more susceptible to erosion and resulting in an increase in the K value.In contrast,temperate grasslands and alpine meadows have higher vegetation cover,richer organic carbon pools,and stronger root reinforcement,leading to noticeable organic matter accumulation and enhanced aggregate stability after grazing disturbance,which decreases the K value.Therefore,temperate grasslands and alpine meadows with high vegetation cover and abundant organic carbon pools exhibit stronger resistance to disturbance.In addition,the erodibility of deeper soil layers(10-30 cm)is more sensitive to disturbance,with K values increasing significantly with depth.