Abstract: Riparian vegetation buffer zone can effectively remove nonpoint source pollutants from surface runoff. We used the method of simulating surface runoff to investigate the interception effect on pollutants and the influencing factors of different width riparian vegetation buffer zone of four Pinus massoniana plantations with slopes of 11°, 15°, 17° and 21° in the Danjiangkou reservoir area. Soil permeability was measured by double ring infiltration test. Soil density and maximum water-olding capacity were measured by ring knife method. The thickness and biomass of litter under different slopes were measured. The results showed that slope, width, litter thickness and litter biomass were the main factors affecting the interception rate. Under the four slope conditions, the interception rate increased with the width and decreased with the slope. To obtain 80% of interception rate of four non-oint source pollutants, the width of buffer zone should be about 34 m when the slope of the riparian vegetation buffer zone was 11°, about 40 m for the slope of 15°, 45 m for the slope of 17°, and 48 m for the slope was 21°. Our results provide reference for the construction and management of riparian vegetation buffer zone of Pinus massoniana plantations in the reservoir area.

Key words: riparian vegetation buffer zone, slope, interception rate, water purification, Danjiangkou reservoir area.