Study on Optimum Rate of Nitrogen,Phosphorus and Potassium for Super Hybrid Middle Rice Nitrogen-Saving Cultivation

3414field experiments of fertilizer effects were conducted to explore the economical N rates and the optimized combination of N,P and K for Super Hybrid Middle Rice Y-Liang you No.1 Nitrogen-saving cultivation,the mathematic mode was set up after analyzed the relationship between the SCU application rate,the allocation of N,P,K fertilization and grain yield.The results indicated that grain yield was significantly affected by the rate of Nitrogen applied,but there were no significant effect in the allocation of N,P,K fertilization on grain yield;the order of the effects of N,P,K fertilizer on grain yield was NKP;The maximum yield(10500.9kg/hm2) was obtained with the rates of N,P,K were 205.2 kg/hm2,38.8 kg/hm2,158.6kg/hm2,respectively,Recommended fertilization combination of N,P,K for more than 9750kg/hm2 yield were N 163.3-196.7 kg/hm2,P2O5 57.2-85.3 kg/hm2,K2O 175.5-214.5 kg/hm2.