The loss of nitrogen and phosphorus due to excessive fertilizer application has become a major form of agricultural non-point pollution. In order to explore the impact of different planting patterns (conventional cultivation, green rice-frog ecosystem and organic rice-frog ecosystem) on nitrogen and phosphorus loss, a field experiment in three paddy fields was conducted to analyze the characteristics of nitrogen and phosphorus in surface water, runoff, and leakage as well as rice yield.

The results showed that the order of average concentration of total nitrogen (TN) in surface water was conventional cultivation (18.87 mg·L^-1), followed by green rice-frog ecosystem (8.98 mg·L^-1) and organic rice-frog ecosystem (8.20 mg·L^-1).Compared with conventional cultivation, green rice-frog ecosystem and organic rice-frog ecosystem decreased TN loss during rice growth season by 15.27% and 25.76%, respectively. Ammonia (NH₄⁺-N) was the main form of TN runoff. The leaching loss rate of TN was highest under conventional cultivation, followed by green rice-frog and organic rice-frog, with NO₃^--N as the main form of TN leaching. The ratio of total TN loss to nitrogen fertilizer use in the three treatments was in the range of 1.25% 2.38%, all less than 3%. Average total phosphorus (TP) concentration of surface water was in the following order: organic rice-frog ecosystem (0.82 mg·L^-1) > green rice-frog ecosystem (0.64 mg·L^-1) > conventional cultivation (0.37 mg·L^-1). Total loss of TP was highest under organic rice-frog, followed by green rice-frog and conventional cultivation. Rice yield was highest under conventional cultivation, followed by organic rice-frog and green rice-frog ecosystems. Compared with conventional cultivation, yield under green rice-frog ecosystem and organic rice-frog ecosystem decreased respectively by 19.33% and 8.15%.

Results showed that organic rice-frog ecosystem and green rice-frog ecosystem effectively controlled nitrogen and phosphorus loss in paddy fields although production decreased. Production quality and economic benefits of organic rice-frog ecosystem were better than those of green rice-frog ecosystem and conventional cultivation. The requirements for organic rice-frog ecosystem were higher than those for green rice-frog ecosystem and conventional cultivation treatment.