Effects of Controlled and Mid-gathering Irrigation Mode of Paddy Rice on the Pollutants Emission and Reduction

The experiment was carried out in Nanjing Vegetables (Flowers) Scientific Institute with 4 kinds of irrigation and drainage treatments, rice field discharge, nitrogen concentration and total nitrogen emissions in drainage water were studied during the rice growth period. The results showed that discharge in controlled and mid-gathering irrigation reduced by 23.8% -27.7% compared with the other three treatments, It also showed that the total emissions of pollutants in drainage discharge reduced significantly, of which the reduction of NH4+-N reached by 29.1-33.3% and NO3--N reached by 34.3% -51.3% compared with the other three treatments. The results indicated that controlled and mid-gathering irrigation had good environmental effects through accumulating rainfall, achieving the effect of water and fertilizer conservation and reducing pollutant emissions.