Abstract:

In order to more intuitively and scientifically reflect the changes of soil and vegetation ecological benefits of the abandoned farmland in the shallow mountainous area of Qilian Mountains,the soil physicochemical properties and vegetation coverage were measured and analyzed in Shandan Dahuangshan Demonstration Area of Soil and Water Conservation technology in the shallow Qilian Mountains.The results indicated that soil moisture and bulk density in seabuckthorn forest were lower than those in grassland,while soil moisture capacity and porosity were higher.Soil bulk density was significantly negatively correlated with soil water holding capacity,capillary porosity and total porosity (P<0.05).Soil water storage of seabuckthorn forest was slightly higher than that of grassland,but the difference was not significant (P>0.05).The contents of soil nutrients,such as electrical conductivity,available K,available phosphorus and organic matter,in the enclosed grassland were higher than those in the unclosed grassland and the seabuckthorn forest.The contents of pH and alkali-hydrolyzable nitrogen in the unclosed grassland were higher than those in the other land types,and the total nitrogen content in the seabuckthorn forest was slightly higher than that in the other land types.Between 2017 and 2020,the vegetation coverage in the demonstration area increased from 69% to 78.8%,with an average annual increase of 3.26%.

Key words: abandoned farmland, soil nutrient, vegetation coverage, Qilian Mountains