Effects Of Nitrogen Fertilizer Management On Growth And Nutrient Uptake Of Winter Wheat

In order to explore the suitable nitrogen levels,the time of nitrogen application and the ratio of the period in Central Shaanxi area of winter wheat.The through the field experiment,the main winter wheat were studied under different N fertilizers,different nitrogen application time and proportion,the growth,yield and dry matter,nitrogen distribution and transport difference.The test set N1(100kg/ha),N2(200kg/ha),N3(300kg/ha)a total of 3 nitrogen levels,each level of nitrogen fertilization on nitrogen during the 3 treatments were: T1 fertilizer as base fertilizer a fertilizer as base fertilizer;T2 50%,50% T3 50% at jointing;as base fertilizer,30% fertilizer,20% flowering fertilization;to set up a N0 no fertilizer treatment,a total of 10 treatment.(1)The plant height of wheat reached its maximum at filling stage,and the leaf area index reached the maximum in flowering period.When the nitrogen application time and proportion were the same,both of them increased with the increase of nitrogen application rate.Nitrogen topdressing in flowering stage can slow down leaf senescence.The SPAD value(chlorophyll content measured the Soil and Plant Analyzer Development)of wheat increased at first,then decreased,and reached the highest stage at jointing stage.Nitrogen application can increase the SPAD value of leaves,and within a certain range,it increases with the increase of nitrogen application rate,and the shift of nitrogen fertilizer can slow down the attenuation of SPAD value.The net photosynthetic rate of wheat was basically the same as that of SPAD.The application of nitrogen at anthesis could improve the net photosynthetic rate in late growth stage of wheat.when delay the time of Nitrogen use can improve the transpiration rate and leaf water use efficiency of wheat;the higher the nitrogen application rate,transpiration rate of wheat is high,but the nitrogen and nitrogen difference shows that promote excessive fertilization on wheat transpiration rate did not help.The water use efficiency of leaves increased with the increase of nitrogen application rate.(2)the dry matter accumulation and nitrogen accumulation at anthesis and maturity of wheat increased with the increase of nitrogen application rate,but there was little difference between N2 and N3.When the amount of nitrogen applied was certain,the dry matter allocation and distribution ratio of grain could be increased by shifting the nitrogen fertilizer,and the dry matter accumulation after anthesis could be significantly increased when use nitrogen at anthesis.When the nitrogen period and proportion is certain,the right amount of nitrogen can improve wheat anthesis dry matter translocation from vegetative organs to grain,remobilization amount and rate of vegetative organs with increasing fertilization decreased after anthesis dry matter accumulation increased with nitrogen application increased firstly and then decreased.Nitrogen application could significantly increase the nitrogen translocation of crops,but the rate of low nitrogen treatments translocation and the contribution to nitrogen accumulation of vegetative organs were higher than those of high nitrogen treatments without nitrogen treatment.When the amount of nitrogen use is the same,the beginning fertilizer + jointing fertilizer own the maximum transfer amount,but three times application transfer rate is the highest.Nitrogen application at different stages could increase nitrogen uptake after anthesis.(3)The dry matter accumulation of wheat at mature period and grain yield showed a linear positive correlation,when the nitrogen period and proportion is cretin,the grain yield of wheat in medium fertilizer and high fertilizer treatment had no significant difference,namely excessive nitrogen did not increase yield;spike number of wheat increased with increasing nitrogen the amount of weight decreased with the increase of nitrogen,when the nitrogen amount is cretin,delay the nitrogen use time can significantly increase crop grain weight and panicle length,when base fertilizer: jointing fertilizer: booting stage for 5:3:2 can obtain the highest grain yield.The water consumption in the whole growth period of wheat increased with the increase of nitrogen rate,but the effect of nitrogen fertilizer on water consumption in the whole growth period was little.The water use efficiency of wheat increased first and then decreased with the increase of nitrogen application rate,and the water use efficiency of wheat was significantly increased after the removal of n fertilizer.(4)when the nitrogen and the proportion is cretin,the nitrogen utilization efficiency,nitrogen uptake efficiency,nitrogen utilization efficiency,nitrogen agronomic efficiency,nitrogen partial productivity and nitrogen recovery rate of wheat decreased with the increase of nitrogen and the difference is significant.When the amount of nitrogen was the same,the nitrogen use efficiency,nitrogen absorption efficiency and nitrogen recovery rate showed as T3>T2>T1,and the nitrogen use efficiency showed as T3>T1 and T2.When the nitrogen and the proportion is cretin,the soil nitrate nitrogen accumulation of mature stage increased with the increase of nitrogen,when the nitrogen amount is cretin,the soil nitrage nitrogen of nitrogen application at different stage is much lower than the nitrogen use as base fertilizer.Fertilization at anthesis increased nitrate nitrogen residue in mature soil surface.Under the condition of the same amount of nitrogen,T1 treatment of nitrate nitrogen accumulation >T2 treatment >T3,visible,sub application of nitrogen is conducive to reduce soil nitrate nitrogen residue.