Synergistic effects of nano-biochar and crop on reducing rainwater runoff and phosphorus loss from sloping farmland.

Biochar application can reduce losses of runoff from rainfall and increase phosphorus retention on sloping farmland. However, high application rates and high mobility of biochar present a challenge to the ecological environment, emphasizing the need for innovative solutions. This study investigated the potential benefits of applying nano-biochar (NBC) in combination with different crops on sloping farmland. Sloping plots were amended with varying mass contents of NBC (0.1, 0.5, 0.7, 1.0, and 0.0% as the control) by band application and planted with various crops (caragana, alfalfa, soybean, and maize). Simulated rainfall was applied 40–100 min to each plot and the runoff, sediment, and available phosphorus were collected. The results indicated that NBC application could improve rainfall interception on sloping soil by 18.08–31.14% and reduce cumulative runoff and sediment by 10.88–31.75%. With increasing applications of NBC, most of available phosphorus was retained in the soil, and available phosphorus losses were reduced by 22.90–43.01% compared with the control. The 1.0% NBC application and alfalfa combination showed the greatest combined effect in reducing rainwater runoff and phosphorus loss. The combination of crops and NBC application was an effective solution for preventing sediment and phosphorus loss caused by rainfall on sloping farmland. [ABSTRACT FROM AUTHOR]