Effects Of Accumulative And Reducing Application Of Nitrogen And Phosphorus On Maize Growth And Nutrient Efficiency

Maize is the largest food crop in China and its planting area reached nearly 422 million acres.The study of nitrogen and phosphorus on accumulation and reduction application would effect the growth,nutrient uptake and soil nutrient of maize,which is of great significance to improve high yield and high efficiency of maize and the utilization rate of fertilizer and soil sustainable utilization.In this study,based on 5 consecutive years of fertilization experiment,the field experiment last two years(2014-2015).Each 5 levels of nitrogen and phosphorus fertilizer were set up.In 2014,the number of 5 nitrogen(N)utilization was 0,97.5,195,292.5,390kg/hm2 with marking as N0,N1,N2,N3,N4,respectively.5 p(P205)with volume of 0,37.5,75,112.5,150,kg/hm2,marked as P0,P1,P2,P3,P4.Three treatments were set up based on 5N and 5P in 2015,including no less nitrogen(FN/FP),50%(RHN/RHP)less nitrogen and less nitrogen(100%RAN/RAP)to study the effects of nitrogen and phosphorus accumulation and reduction application on maize yield,dry matter accumulation,nutrient distribution and nutrient absorption of nitrogen and phosphorus utilization efficiency and soil nutrient change.The main results showed as follows:(1)The accumulation of nitrogen fertilizer had a significant yield increasing effect on maize yield.No nitrogen treatment was significantly lower than that of the nitrogen fertilizer treatments.Maize yield with the cumulative amount of nitrogen appeared the trends of first increased and then decreased,and the quantity of nitrogen fertilizer reached the maximum with the yield of 195 kg/hm.Therefore,the cumulative application of appropriate nitrogen fertilizer had significant promoting effect on maize growth.Biomass,nutrient accumulation and leaf area index of nitrogen increased with in the whole growth period increased firstly and then decreased,and reached the maximum in the nitrogen amount of 195 kg/hm2.Soil nitrate nitrogen increased gradually with the increase of nitrogen application rate,and the more nitrate nitrogen accumulated in the soil during the harvest period increased year by year.However,with the accumulative application of nitrogen fertilizer,the average nitrogen use efficiency of nitrogen treatment decreased year by year.(2)The accumulation of phosphorus fertilizer significantly increased effect on maize yield and maize yield with phosphorus accumulation increased and then stabilize.P(P2O5)112.5 kg/hm2 output reached maximum and excessive production of phosphorus even appeared a downward trend.The plant height and ear diameter of maize with phosphorus treatment were significantly higher than those without phosphorus treatment.The cumulative application of P fertilizer decreased the growth of maize biomass,and the excessive accumulation of phosphorus affected the growth of maize,and the plant biomass decreased significantly.With the application of phosphorus year by year,P apparent utilization rate and agronomic efficiency of phosphorus fertilizer decreased and soil phosphorus accumulated continuously.Soil available P in the silking and harvesting stages of maize increased gradually with the increase of P application rate.(3)On the condition of 5 year nitrogen cumulation,on N1 and N2 level RAN treatment would decreased the nitrogen phosphorus and potassium accumulation,yield of maize significantly,and the yield of RHN treatment was decreased but not significantly with the dry matter accumulation of maize.N3 levels of RAN and RHN treatments had no significant effect on the yield of maize with maize growth and accumulation no significant effect.On the level of N4 RHN treatment could significantly increase the yield of maize and the yield of RAN was significantly decreased.On the basis of N3 and N4,RHN and RAN treatments had no significant effects on nitrogen accumulation,and RHN treatment could significantly increase nitrogen utilization efficiency,nitrogen physiological efficiency and agronomic efficiency of nitrogen fertilizer.(4)On the condition of 5 year phosphorus cumulation,on P1 level RAP treatment will significantly decrease the yield and biomass,and the yield of RHP treatment has a downward trend.P2 level of PAP and RHP treatments had no significant effect in maize yield and plant biomass.On the basis of P3 and P4,RHP and RAP treatments on the growth of maize there was no remarkable effects and slightly higher.Phosphorus application at 75 kg/hm2 level(P0 and P1)reduced P application rate to pre growth rate of maize,and when the application rate of continuous phosphorus was higher than 75 kg/hm2(P2,P3,P4),RHP treatment did not reduce the growth rate of maize at the whole growth stage,but had some promoting effect.The content of available P increased first and then decreased with the growth period of maize,and reached the highest in silking stage.In addition to the continuous application of phosphorus 150 kg/hm2,RHP treatment would not significantly affect the soil available phosphorus content in each period.Under the other phosphorus levels,RHP and RAP treatment will significantly reduce the content of soil available phosphorus.In summary,maize accumulation fertilization should be applied in a reasonable accumulation of nitrogen and phosphorus fertilizer in order to ensure the maize yield not decline and soil fertility remained.Accumulation of high nitrogen and high phosphorus level should be reducing fertilization,soil fertility and ultimately play role in maize production of high yield and high efficiency.