Abstract：Different rice irrigation and drainage modes were set up at three nitrogen application levels by taking farmland water level as control index. The yield and yield components of rice under these modes were studied. TOPSIS model based on entropy weight method was used to evaluate these irrigation and drainage modes to screen a rice irrigation and drainage mode that can achieve three goals such as high efficiency, water saving and pollution control. The results showed the alternate stress of drought and waterlogging at tillering stage had the most obviously inhibitory effect on the yield and pollution control index of rice but affected a little on water saving index. Under the alternate stress of drought and waterlogging, a low nitrogen fertilizer application level had an obviously inhibitory effect on rice growth and development. There was no significant increase in rice yield at a high nitrogen fertilizer application level. The leaching capacity of nitrogen at a high nitrogen fertilizer application level was larger than that at a low nitrogen fertilizer application level. The good-fitness of the controlled irrigation and drainage mode at a 300 kg/hm2 nitrogen fertilizer application level was 0.694 5 based on TOPSIS model. The alternation stress of drought and flood at tillering stage not only has the greatest adverse effect on rice growth and development of, but also has the worst effect on pollution control and emission reduction. Through model evaluation the optimal irrigation and drainage scheme is the controlled irrigation and drainage mode with the nitrogen application level of 300 kg/hm2.
