Abstract: The ecological buffer strip between terrestrial ecosystem and aquatic ecosystem can effectively intercept nitrogen, phosphorus, herbicides, and other pollutants in surface runoff into rivers and lakes. Alfalfa, Kentucky bluegrass, tall fescue, ryegrass, and white clover were selected to build ecological buffer strips. A field runoff simulation experiment was conducted to explore the effects of vegetation type and buffer strip length on the inhibition and control of surface runoff, ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), total phosphorus (TP), dissolved phosphorus (DP), particulate phosphorus (PP), acetochlor (AC), and atrazine (AT). The results showed that the five types of ecological buffer strips significantly improved the resistance and control efficiency of runoff and non-point source pollutants, and that the control efficiency of pollutants gradually increased with the increased buffer length. Buffer strips of different vegetations effectively reduced surface runoff, with an order of ryegrass > tall fescue > Kentucky bluegrass > white clover > alfalfa. The 4 m long ryegrass buffer strip had the highest control efficiency for NO₃^--N, TP, DP, PP, and AC, which reached 72.2%, 73.2%, 68.8%, 83.5% and 70.8%, respectively. The 4 m long tall fescue buffer strip had the highest control efficiency for NH₄⁺-N (88.0%) and AT (77.3%).

Key words: ecological buffer strip, acetochlor, atrazine, non-point source pollution.