Through experiments in standard runoff plots,this paper studied effects of vetiver hedgerow on bulk density,particle distribution and nutrient loss in the surface soil layer(0-20 cm) of different slope farmland in the purple soil area,Sichuan,China.The results showed that Vetiver hedgerow could reduce soil bulk density,but the effect was not significant.Under hedgerow's effect,small soil particles(silt,clay) obviously enriched in the bottom and middle of slope,and the quantity of small particles loss reduce...