Effects Of Nitrogen And Phosphorus Fertilizer On Soil Nutrient And Maize Yield

【Object】The effect of different combination ratios of N, P fertilizer on soil nutrient contents,maize nutrients uptake and yield were investigated with a field experiment. The objective is(1): to explore the changes of soil nutrients, maize N, P nutrients uptake and disproportion under different N, P fertilizer application rates.(2): to provide an appropriate N, P combination rate which can improve maize yield and N, P fertilizer use efficiency.【Method】An field experiment was conducted in grey desert soil of North Xinjiang. The seven N,P combination ratios were designed as N0P150, N225P75, N300P75, N450P75, N300P0, N300P150, N300P300.【Result】(1) With the N fertilizer application rate increasing, the NO3--N and NH4+-N contents in 0-1m soil layer increased. The soil inorganic N accumulation showed of negative when the N application rate was less than 225 kg/hm2, but it accumulated significantly when N application was higher than 300 kg/hm2.The inorganic N accumulation of N300P75 and N450P75 were increased38.7% and 100% than initial value. When the N application rate was 300 kg/hm2, and combined with phosphorus, the soil inorganic N content was decreased with the P application rates(<300kg/hm2) increasing.(2) The contents of Olsen-P, H2O-P and Ca Cl2-P in soil were respectively decreased 63.2%,33.9% and 45.1% than initial value under no P fertilizer application. The soil Olsen-P, H2O-P and Ca Cl2-P were increased with the P application rate increase, and the Olsen-P, H2O-P, Ca Cl2-P contents were respectively increased 79.5%~130%, 27.6%~77.6%, 28.3%~100% than initial value when P application was higher than 150 kg/hm2. But phosphorus was fixed and raise nitrogen can decrease Olsen-P and Ca Cl2-P contents in the soil.(3) Dry matter weight of maize was increased significantly with N, P fertilizer application rates increasing. But there was no significantly difference when the N application rate was higher than 300 kg/hm2 and P application rate was higher than 150 kg/hm2.(4) The N, P nutrients uptake was increased with the N, P fertilizer application rates increasing when the N application rate was fewer than 450 kg/hm2 and P application rate was fewer than 300 kg/hm2. The N, P nutrients of maize bracts and cob transport to grain was significantly promoted by N, P fertilizer application. The N distribution proportions was the most in leaf and grain, which distribution proportion was 79.2~82.6%. And the P distribution proportions 56.9~62.5% in grain of maize.(5) The spike grain number and 100-grain weight were increased with N, P increasing, and the yield of maize was also increased significantly. But the maize yield was decreased when the N application rate was 450 kg/hm2 and P application rate was 300 kg/hm2. The order is N300P150>N300P75 >N300P300 >N450P75 >N225P75 >N300P0 >N0P150.(6) The N use efficiency was increased significantly with N application rate increasing, but it was decreased when the N application rate was higher than 300 kg/hm2. The P use efficiency was reduced significantly with P application rate increasing.【Conclusion】Applying nitrogen fertilizer 300 kg/hm2 and combined with phosphorus fertilizer75~150 kg/hm2 could decrease soil inorganic N contents, and enhance the nutrient absorption of maize, increase the yield of maize significantly. So the N 300 kg/hm2, P 75~150 kg/hm2 is a reasonable fertilizer application rate in the study area, not only get higher maize yield and fertilizer use efficiency, but also reduce the nitrogen and phosphorus source pollution risk.