Abstract: Field experiment was conducted to investigate the effects of riceduck farming on the water environment in paddy field. The results showed that under rice-duck farming, the temperature and pH value of the surface water in paddy field decreased, and the electrical conductivity, oxidationreduction potential, turbidity, and the contents of nitrogen (N), phosphorus (P) and potassium (K) increased. The total N, P, and K increased by 1.85-5.06 times, 2.01-8.70 times, and 42.79%-109.18%, respectively, as compared to those in conventional rice farming. All of these illustrated that rice-duck farming improved the paddy field water environment and nutrient supply, optimized the ecological environment of paddy field, and promoted the growth and development of rice.

Key words: Korean pine-broadleaved mixed forest, standing tree, decay of the trunk near root, site condition, soil physical-chemical properties, Xiao Xing’an Mountains.