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In this study, runoff plot test was carried out in Rainy Area of West China to study the adsorption and analytical characteristics of phosphorus on ryegxass(Lolium perenne L.) and natural grass soil planted on different slopes. The results showed that the content of available phosphorus and total p in ryegrass was higher than that in natural grassland. Langmuir equation can well fit the adsorption of phosphorus on soil, and the maximum adsorption capacity and adsorption coefficient are 434.76mg/kg and 0.57, respectively, which all appear in ryegrass field. The secondary kinetic equation can well fit the adsorption dynamic characteristics of phosphorus. The equilibrium adsorption capacity and adsorption rate are between 44.64∼49.06 mg/kg and 0.0258~0.0466 kg/(mgh), and the maximum value is in ryegrass field. The phosphorus analysis rate of the soil in the study area was 30.93∼34.41%, which showed that the natural grassland was > ryegrass. At the same adsorption amount, the soil phosphorus content was > ryegrass. The results showed that the soil phosphorus fixation effect of ryegrass was good. The rational planting of ryegrass on the slope of yuping district in west China can effectively reduce the pollution of phosphorus from non-point sources.

Taking Qingxi small watershed in Hanyuan County of Ya’an City as an example, the effects of four different economic fruit forests on the sloping farmland in the dry-hot valley region on the soil nutrient loss before and after the flood season were studied. The results showed that after the flood season, the soil Organic matter(OM) content of the four economic fruit forests increased, which was characterized by large cherry forest > peach forest > pear forest > pepper forest, but no crop cultivated land decreased. Alkali nitrogen(AN) and Available phosphorus(AP) of four economic fruit forests decreased, but the degree of declining was lower than that of cropless cultivated land. The Total nitrogen(TN) content of the soil of the cherry forest and peach forest decreased, but the degree of declining was lower than that of the cropless cultivated land, while the pear and pepper forests increased. The large cherry forest and pepper forest content of Total phosphorus(TP) in the soil was reduced, while the peach and pear forests increased. In terms of OM, large cherries are the best choice for local fruit forest. Pear trees are the best choice for the change of N or P elements. From the comprehensive analysis of soil nutrient changes, pear trees are the best fruit forest in the region.