Slope farmland covers an area of 3,513 × 10 4 m 2 in China, which is a major source of soil and water losses. Soil erosion has been identified as one of the major processes contributing to soil and water quality degradation [1-4]. Recently, the application of excessive fertilizers and manures to agricultural land can increase the level of phosphorus (P) in the purple soil region of Sichuan, China. P is the element primarily responsible for water eutrophication. The loss of P with soil erosion can cause environmental problems due to their effect on water eutrophication [5]. P loss in the purple soil of sloped farmlands has caused much concern [6-9]. Thus, studies should consider P loss caused by runoff and sediments.