Effects of Irrigation and Fertilization on Nitrogen and Phosphorus Runoff from Paddy Field

The article explored the influence of nitrogen fertilizer application with several times under different irrigation modes on nitrogen and phosphorus loss in paddy fields under field experiment condition.The results indicated that the runoff of total nitrogen and phosphorus was between 4.41~17.85 kg/hm2 and 0.28~0.44 kg/hm2 under different fertilizer treatments with traditional irrigation respectively.The loss percentage of nitrogen and phosphorus fertilizer was respectively about 3.2% and 0.17%.Compared to traditional irrigation,the average loss of total nitrogen and phosphorus relative were reduced by 22.99% and 10.01% under intermit irrigation,with only one percentage point loss of the of nitrogen fertilizer and with the same loss of total phosphorus.It was included that the yield of intermit irrigation was higher about 7.35% than that of traditional irrigation.The treatment of nitrogen with four times application under the intermit irrigation would decrease the runoff of nitrogen and phosphorus and could increase the yield.