Abstract: Livestock manure applications may result in potential water pollution. Runoff experiments were established in South China to study the characteristics of runoff pollutant discharge in paddy fields caused by swine manure utilization. Four groups of fertilization management practices were considered in this study, including chemical fertilizer application (CK), fresh manure application (C3), organic manure application (C2) and biogas slurry application (C1). Results show that the concentration of total nitrogen, ammonia nitrogen and total phosphorus in the runoff peaked within the first 7 days after fertilization, then rapidly declined before reached stable on the 21st day. In C3, the TN loss reduced by 24.5% compared with CK. On the contrary, the NH₃-N loss increased by 33.3%, the TP loss increased by 25.8%, and the COD loss increased by 24.2%. Similarly, in C2 the TN loss reduced by 35.1%, and the COD loss increased by 8.8% compared with CK. There was no significant difference of TP loss and NH₃-N loss between CK and C2. In C1, the TN and TP loss reduced by 33.9% and 35.9% respectively, compared with CK. Nevertheless, there was no obvious change in NH₃-N loss, and the COD loss increased by 22.2%. In terms of potential water pollution, C1 and C2 appeared to be the more appropriate swine manure application methods, as they could not only reduce chemical fertilizer usage, but also decrease the risk of N and P pollution caused by surface runoff. Fresh manure application is not suggested in agriculture production.

Key words: livestock feces, paddy field, non-point source pollution, pollutant discharge load