Effects Of Irrigation Method And Nitrogen Application On Post-anthesis Nitrogen Metabolism And Grain Yield Of Winter Wheat

In order to explore photosynthetic production,nitrogen metabolism,nitrogen utilization characteristics and yield formation of winter wheat after flowering in Northern Henan Province,this research used Aikang58 as experimental material and adopted split plot design which was treated by irrigation（drip irrigation,flood irrigation）,straw treatment（straw returning,straw not returning）and five nitrogen application levels.The main conclusions are as follows:1.The chlorophyll content and the rate of net photosynthetic in flag leaves of winter wheat after flowering were the highest at the flowering stage under different treatments,and then gradually declined with the process of grain filling.The intercellular CO₂ concentration in the flag leaves gradually increased with the growing period.Transpiration rate and stomatal conductance were the highest 14 or 21 days after flowering,and then decreased.Analysis of variance showed that the nitrogen and irrigation methods had significant effects on chlorophyll content,net photosynthetic rate,intercellular CO₂ concentration and stomatal conductance.The chlorophyll content,net photosynthetic rate and stomatal conductance in flag leaves of wheat improved under drip irrigation with N₂₈₀(280 kg·hm^-2).The treatment of drip irrigation and straw mulching could increase transpiration rate,and the concentration of intercellular CO₂ under diffuse irrigation was low.2.With the process of grain filling,GS,GPT,GOGAT and NR activity in flag leaves and grain of wheat showed a downward trend,and these enzymes related nitrogen metabolism reached the highest at anthesis and 7 days after anthesisand then gradually decreased.Analysis of variance showed that the amount of nitrogen applied had a significant effect on the GS,NR,GOGAT and GPT activity in flag leaves and grain in wheat after anthesis.With the increase of nitrogen application rate,the GOGAT activity of flag leaves and grain increased gradually.Within the range of 0²80 kg·hm^-22 nitrogen application,the NR activity of flag leaves and grain,and the GPT activity of grain increased with the increase of nitrogen application rate.Within the range of 0²20 kg·hm^-22 nitrogen application,the GS activity of flag leaves and grain,and the GPT activity of flag leaves gradually increased with the increase of nitrogen application rate.3.The correlation analysis of protein content and yield with enzymes related nitrogen metabolism showed that the GS activity of the flag leaves after anthesis was significantly correlated with grain yield and protein content.The NR and GOGAT activity of the flag leaves,and the GOGAT,NR,GS and GPT activity of the grain had positive or significantly positive correlation with grain yield,protein content and yield after anthesis.Increasing the activity of enzymes related nitrogen metabolism after anthesis can increase grain protein content and yield.4.Nitrogen application rate had a significant effect on the number of spikelets.Within the range of0²20 kg·hm^-22 nitrogen application and under drip irrigation,Fertile spikelets without straw returning were higher than that understraw returning.However,within the range of 0²20 kg·hm^-22 nitrogen application and under flood irrigation,fertile spikelets without straw returning were lower than that under straw returning.When nitrogen application rate was 280 kg·hm^-2,the yield of wheat was higher when the straw was not returned to the field under flood irrigation and when the straw was returned to the field under drip irrigation.Under the same straw and irrigation treatments,nitrogen translocation amount was the highest under N₂₈₀80 treatment,and the nitrogen utilization efficiency and nitrogen harvest index of N₁₆₀60 and N₂₈₀80 were significantly higher than those of N₂₂₀,N₀ and N₃₄₀40 treatments.Nitrogen utilization efficiency and nitrogen harvest index of N₃₄₀40 were the lowest.In general,the nitrogen harvest index and utilization efficiency of nitrogen and water were higher under nitrogen application rate of 160 kg·hm^-22 and 280 kg·hm^-2,respectively.Flood irrigation with straw returning and drip irrigation without straw returning under nitrogen application rate of 280 kg·hm^-22 had the higher yield.Under the drip irrigation,the photosynthetic capacity and enzymes acticity related nitrogen metabolism under nitrogen application rate of 280 kg·hm^-22 were significantly higher.Considering the input of water and nitrogen,drip irrigation with straw returning to the field under nitrogen application rate of 280kg·hm^-22 could be used as the cultivation method of saving water,reducing nitrogen and producing high yield in North Henan Province.