The loss of N in farmland is an important cause of agricultural non-point source pollution, which seriously impacts the aquatic environment. A two-year(2017–2018) experiment was conducted to investigate the character...The loss of N in farmland is an important cause of agricultural non-point source pollution, which seriously impacts the aquatic environment. A two-year(2017–2018) experiment was conducted to investigate the characteristics of runoff and N losses under different tillage practices. Taking downslope ridge planting and cross ridge planting as the experimental treatments,the characteristics of surface runoff, interflow, and N losses in sloping farmlands with yellow soil were studied throughout the maize growth period. As the rainfall increased, the surface runoff and interflow also increased. The surface runoff and N losses in the surface runoff of downslope ridge planting were significantly higher than those of cross ridge planting. The interflow volumes and N losses in the 0–20 and 20–40 cm soil layers of the cross ridge planting were significantly higher than those of the downslope ridge planting. The total N(TN) losses from surface runoff accounted for 54.95–81.25% of the N losses from all pathways. Therefore, we inferred that surface runoff is the main pathway of N losses. Dissolved total N(DTN) was the main form of N loss under different tillage measures, as it accounted for 55.82–94.41% of the TN losses,and dissolved organic N accounted for 52.81–87.06% of the DTN losses. Thus, we inferred that dissolved N is the main form of N loss. Future research must focus on the prevention and control of the N losses during the maize seedling stage to reduce the environmental pollution caused by ammonium N through runoff.展开更多
基金financial support provided by the National Natural Science Foundation of China(41271307)the Key R&D Project of Sichuan Province,China(2019YFS0463)。
文摘The loss of N in farmland is an important cause of agricultural non-point source pollution, which seriously impacts the aquatic environment. A two-year(2017–2018) experiment was conducted to investigate the characteristics of runoff and N losses under different tillage practices. Taking downslope ridge planting and cross ridge planting as the experimental treatments,the characteristics of surface runoff, interflow, and N losses in sloping farmlands with yellow soil were studied throughout the maize growth period. As the rainfall increased, the surface runoff and interflow also increased. The surface runoff and N losses in the surface runoff of downslope ridge planting were significantly higher than those of cross ridge planting. The interflow volumes and N losses in the 0–20 and 20–40 cm soil layers of the cross ridge planting were significantly higher than those of the downslope ridge planting. The total N(TN) losses from surface runoff accounted for 54.95–81.25% of the N losses from all pathways. Therefore, we inferred that surface runoff is the main pathway of N losses. Dissolved total N(DTN) was the main form of N loss under different tillage measures, as it accounted for 55.82–94.41% of the TN losses,and dissolved organic N accounted for 52.81–87.06% of the DTN losses. Thus, we inferred that dissolved N is the main form of N loss. Future research must focus on the prevention and control of the N losses during the maize seedling stage to reduce the environmental pollution caused by ammonium N through runoff.
