Effects of N Application Rate on Nitrogen Absorption,Utilization and Yield of Wheat under Different Soil Fertility after Rice

Took Huaimai 19 and Yannong 19 as materials,the effects of nitrogen rates on nitrogen uptake,nitrogen utilization and yield of wheat under high,middle,low soil fertility were studied.There were significant linear relations between nitrogen application rate and nitrogen uptake rate of wheat plants in each periods;N utilization rate and yield increased with the increase of nitrogen application rate at first,then showed a downward trend,and showed an upward trend with the fertility level;the highest N absorption efficiency and agronomic N use efficiency were achieved at the lowest nitrogen rate in different soil fertility levels.The highest N utilization rate and grain yield were obtained when nitrogen rates were 202.5、270、337.5 kg·hm-2 under high,middle,low soil fertility levels,respectively.