Effects of different hedgerows on surface soil characteristics of sloping farmland in the purple soil area

Through experiments in standard runoff plots, this paper studied effects of leucaena leucocephala hedgerow and vetiver hedgerow on bulk density, particle distribution and nutrient loss of the surface soil (the soil depth was 0-20 cm) of sloping farmland in the purple soil area, Sichuan, China. Results showed that: (1) the two hedgerows can reduce soil bulk density, and vetiver hedgerow had a bigger decline of 12 percent. (2) in plots with hedgerows, silt and clay enriched in the bottom and middle of slopes, and the increment of silt or clay of vetiver hedgerow plot was bigger that of leucaena leucocephala hedgerow plot. (3) on intercepting soil particles, the two hedgerows showed as sand>;silt>;clay. (4) the two hedgerows had a better conservation effect on total nitrogen and total potassium. (5) on total nitrogen, available phosphorus and total potassium, vetiver hedgerow´s effects were stronger than leucaena leucocephala hedgerow´s; on organic matter, alkalined-nitrogen, total phosphorus and available potassium, leucaena leucocephala hedgerow´s effects were stronger than vetiver hedgerow´s. (6) in plots with hedgerows, organic matter, total nitrogen, total phosphorus and available potassium showed an obvious enrichment in slope bottom and in the front of hedgerow. Therefore, increasing the amount of nitrogenous fertilizer and reducing the amount of potash fertilizer were important in this area. And strengthening soil fertilities of slope top and portions faraway from hedgerow were also important.