On the condition of natural rainfall and through the measure method of field runoff plots, an field experiment with six water and fertilizer managements (i.e. none fertilization and routine irrigation, routine fertilization and routine irrigation, optimization fertilization and routine irrigation, increasing nitrogen fertilization and routine irrigation, increasing phosphorus fertilization and routine irrigation, optimization fertilization and optimization irrigation) in 3 years ( 6 stubbles of rice) was carried out to study the effects of water and fertilizer managements on yield, nutrition uptake of rice and loss of nitrogen and phosphorus by runoff from paddy field. The results show that, under the 6 water and fertilizer managements, the dry matter yield of rice is 11629 ~ 19709 kg hm-2 a-1, the uptake of nitrogen, phosphorus and potassium in rice plant are 90 ~ 174 kg•hm-2 a-1, 36 ~ 62 kg hm-2 a-1, 151 ~ 288 kg hm-2 a-1, respectively, and the loss of nitrogen and phosphorus by runoff from paddy field are 14.0 ~ 42.9 kg hm-2 a-1 and 0.244 ~ 0.559 kg hm-2•a-1, respectively. Moreover, the dry matter yield of rice, the uptake of nitrogen and potassium in rice plant and the loss of nitrogen by runoff from paddy field under the treatment of “increasing nitrogen fertilization and routine irrigation” are relative higher than others. And the rice yield and nutrient uptake of “optimization fertilization + optimization irrigation” treatment is equivalent with “routine fertilization + routine irrigation”, but nitrogen and phosphorus loss of surface runoff reduce obviously, and the irrigation water is saved by 900.5 m3 hm-2 a-1, synchronously. Thus, better economical and environmental benefit would be reached by the treatments of “optimization fertilization and optimization irrigation”.
Impact of Alternate Drought and Flooding Stress on Water Use, and Nitrogen and Phosphorus Losses in a Paddy Field