Effects of Different Water and Fertilizer Application on Paddy Soil N and P Fertility

Abstract：Based on the paddy soil productivity on nitrogen and phosphorus,experiment was carried out under different water and fertilizer application in ZIS,Hubei province.The content change of nitrogen and phosphorus of paddy soil under 2 irrigation models combined with 3 nitrogen application had been analyzed,the same as that of its significance test（significance level a=0.05）.The result showed that the conservation of total nitrogen,total phosphorus content at upper layer（0～20 cm） of paddy soil under alternate wet and dry irrigation（AWD） was better than that at lower layer（20～40 cm）.The promotion and recovery of total phosphorus content at lower layer（20～40 cm） of paddy soil under flood irrigation was significant.Compared with no N treatment,the 4 times N treatment could promote the development and conservation of nitrate nitrogen at upper layer（0～20 cm） obviously,and cut down the content of ammonium nitrogen at the lower layer（20～40 cm） significantly.There was significant difference relatively between total phosphorus content at upper layer（0～20 cm） of paddy soil caused by 4 times N and 2 times N treatments.