The Effects Of Two Nitrogen Regulation Modes On The Wheat Population Construction And Yield Formation Under Different Nitrogen Levels

In order to investigate the effects of different nitrogen regulation modes on wheat population dynamics,this experiment was conducted in Yuzhou,Henan province,and Yumai 49-198 was as test material.Under N application level of 0,180,360 kg·ha-1,this test was sprayed three times at reviving to jointing stages with mass concentration of 0%,1%,2%,4% nitrogen fertilizer;Nitrogen fertilizer was applied at 0 kg·ha-1?90 kg·ha-1/180 kg·ha-1 as base fertilizer and also applied at reviving stage(pure nitrogen 0,90,180kg·ha-1),to explore the effect of different nitrogen regulation modes on Nitrogen concentration of wheat plants,population quantity and quality,yield and yield formation.The result were as follows:The effects were distinct under different N nutrition levels at foliar spraying of different concentrations of nitrogen fertilizer.Under low nitrogen levels(N1),foliar application of nitrogen fertilizer could increase spike rate,the leaf nitrogen concentration,the stem and sheath nitrogen concentration,dry matter accumulation.At medium nitrogen levels(N2),the suitable spraying concentration of foliar nitrogen fertilizer(S2,S3)promoted the spike rate,leaf area index,the leaf nitrogen concentration,the stem and sheath nitrogen concentration.Under high nitrogen level(N3),foliar spraying with high concentration(S3,S4)of nitrogen fertilizer resulted in decreased spike rate,leaf area index,the stem and sheath nitrogen concentration,the leaf nitrogen concentration,dry matter accumulation and nitrogen use efficiency.The effects of different spraying concentrations of the yield on wheat were different under different N nutrition levels.The maximum yield was reached when the nitrogen application concentration of nitrogen fertilizer was 1% under 180 kg·ha-1.Under low nitrogen levels(N1),wheat yield and panicle number of a unit area were increased with the increasing foliar spraying concentration,S4>S3>S2>S1;At medium nitrogen levels(N2),the suitable spraying concentration of foliar nitrogen fertilizer promoted yield,S2>S3>S1>S4;Under high nitrogen level(N3),there is a downward trend in the yield because of nitrogen fertilizer.Under different N nutrition levels,it has different effects on population and yield when topdressing at root.Under the same basal nitrogen level,the leaf area index,the stem and sheath nitrogen concentration,the leaf nitrogen concentration dry matter accumulation were increased with the increase of nitrogen fertilizer.At base low nitrogen(B1)level,spike rate and yield were increased with the improvement of fertilizer level;at medium nitrogen(B1)level as base fertilizer,the maximum yield were reached at high(180 kg·ha-1)nitrogen fertilizer level,D3>D2=D1.The nitrogen use efficiency was significantly increased by the two nitrogen regulation methods without the nitrogen as base fertilizer.Foliar application of nitrogen fertilizer could significantly increase the nitrogen use efficiency under the base medium nitrogen level;the effect of nitrogen regulation on nitrogen use efficiency was not significant under high nitrogen levels.