Abstract:

This paper adopts artificial locust forests with 17,13,9 and 4 converted years in typical hilly and gully areas of southern Shanxi Province as the research objects to analyze the soil nutrient content and study its content changes.The results show that:1) at the same soil depth,locust forest show a decreasing trend and significant difference in soil pH with the increase of years of farming.2) The soil ammonia nitrogen content of Robinia pseudoacacia forest in different years of farming tends to increase in different soil depths,and the overall performance is significantly different.Compared with the same soil layer depth of Robinia pseudoacaciaforest in different years of farming,the content of ammonia nitrogen in soil decrease significantly with the increase of years of farming.3) The contents of available phosphorus,total nitrogen and organic matter of locust forest increase with the increase of years under the same soil depth in different years of farming.4) Nitrogen,available potassium and total phosphorus contents of locust forest at the same soil depth are prone to decrease with the increase of years of farming.It can be found that planting locust forest can effectively improve soil nutrient status and has a positive effect on soil improvement and nutrient maintenance.

Key words: hilly and gully area, years of conversion, Robinia forest, soil nutrient content, soil improvement