Study On The Coupling Effect Of High Yield, High Efficient Water And Nitrogen Of Winter Wheat By Drip Irrigation In South Xinjiang

The experiment was carried out in the network room of the experimental station of Tarim University in2016-2017.The Han Dan NO.5316 was used as the research object through the community experiment.The two-factor cracking zone test was used to design the main area for irrigation treatment and the secondary area for nitrogen treatment.Among them,the three water drip amounts of W1(1800 m³·hm^-2),W2(3150m³·hm^-2)and W3(4500 m³·hm^-2)were set,and the nitrogen?urea?was set to N0(0 kg·hm^-2).Four levels of N1(138 kg·hm^-2),N2(207 kg·hm^-2),and N3(276 kg·hm^-2)were used to convert 46%of pure nitrogen into urea.To study the effects of different water and nitrogen treatments on growth traits,photosynthetic characteristics,protective enzyme activities,yield and yield components,and nitrogen use efficiency of winter wheat,and to analyze their coupling effects,and compensation for growth characteristics and yield formation of wheat under water and nitrogen conditions.The effect was to elucidate the mechanism of coordinated increase in yield and water and nitrogen use efficiency,and to find the optimal water and nitrogen management model for drip irrigation wheat,and to obtain the optimal water and nitrogen allocation model for winter wheat,which provided a reference for production.The results showed that:1.Under the W1 level,the appropriate application rate of nitrogen fertilizer is 138 kg·hm^-2?less nitrogen?;increasing nitrogen fertilizer at W2 level can effectively increase the growth and dry matter accumulation of winter wheat,and has extreme value under N3 treatment;Nitrogen excess at W3 level reduced the plant height and leaf area of winter wheat during grain filling and maturing.Therefore,under the condition of ensuring sufficient water,controlling the fertilizer was beneficial to the growth and development of winter wheat,and the decrease of leaf area in the later period was reduced,which reduced the risk of plant lodging.In this experiment,the plant height,leaf area and dry matter accumulation of winter wheat under W3N2 water and nitrogen ratio maintained at a high level.2.The photosynthetic rate of flag leaf of winter wheat increased first and then decreased,and reached the maximum at the flowering stage.At the level of W1,N1 played a role in compensating drought stress,which effectively increased the photosynthetic rate;and the nitrogen fertilizer regulation effect was significant under W2 level.The photosynthetic rate was increased with the increase of nitrogen application rate;the reasonable application of controlling water and nitrogen at the booting stage-flowering stage played an important role in improving the photosynthesis rate of the flag leaf;N0,N1,N2,N3 treatment at W2 level during the grain filling stage Compared with the flowering period,the percentage of N0,N1,N2,and N3 decreased by 11.8%,8.4%,8.5%,and 8.8%,compared with the flowering period,and W3 water conditions significantly decreased.The rate of decline in flag leaf Pn?net photosynthetic rate?played a role in prolonging the photosynthetic functional period of flag leaves;N3 treatment in W3 level led to a decrease in photosynthetic rate,which was due to the high nitrogen stress caused by plants,at which time the nitrogen fertilizer treatment resulted in reduced yield.The SPAD value,Pn?net photosynthetic rate?,Gs?stomatal conductance?,Tr?transpiration rate?and Ci?intercellular carbon dioxide concentration?of W3N2and 234.3?mol·mol^-11 were significantly higher than other water and nitrogen coupling combinations.It indicated that adequate water and adequate amount of nitrogen fertilizer could effectively increase the photosynthesis rate of flag leaf,prolong the photosynthesis function of flag leaf,increase the output of assimilation product,and finally increase the yield.3.CAT?catalase?,POD?peroxidase?,SOD?superoxide dismutase?have a slight increase in enzyme activity at W1 level N1 treatment,so a small amount of nitrogen fertilizer application in dry areas will help winter wheat reproduction.During the growth period,the enzymatic activity of the leaf was increased,and the protective enzyme activity of the adversity was decreased with the increase of nitrogen fertilizer,the content of MDA?malondialdehyde?was increased,the membrane lipid permeability was improved,and the cell membrane was further damaged;W2 and W3 levels,CAT?catalase?,POD?peroxidase?and SOD?superoxide dismutase?maintained high activity with increasing N fertilizer,and MDA?malondialdehyde?content was significantly reduced,and the content of MDA?malondialdehyde?was the lowest under W3N2treatment.The smallest cell membrane damage.4.Increased water and nitrogen application had positive effects on spike number,grain quality and yield of winter wheat,but grain number per panicle was generally lower at W1 level,overall higher at W2 level,and W3 level decreased compared to W2 level.It is considered that there is a certain range of water regulation effect on the number of grains per spike.If the water content exceeds the range of irrigation,it is not conducive to the increase of grain number per panicle;the maximum number of panicles under W3N3is 53.22 panicles and the number of grains per panicle is 24.59 grains under W2N2 treatment.The1000-seed quality and yield performance were the same,with the maximum values of 49.96 g and 9178.80kg·hm^-22 under W3N2 treatment.Overall W3N2 treatment resulted in high winter wheat yield and yield,indicating that W3N2 optimized the yield structure.In the actual production process,when the water is sufficient,the reference amount of nitrogen application rate of 207 kg·hm^-22 and the amount of water injection of 4500 m³·hm^-22 can be used as a reference model for water and nitrogen operations.5.The analysis of nitrogen status of winter wheat plants showed that the total nitrogen accumulation of W2N2,W3N3,W2N3 and W2N2 was 217.77-253.19 kg·hm^-2,and the accumulation of nitrogen in grain was 116.06-142.33 kg·hm^-2.The nitrogen utilization efficiency was 28.722-42.52 kg·kg^-1.The agronomic efficiency of nitrogen fertilizer was 11.74-13.60 kg·kg^-1.The irrigation water use efficiency was 1.59-2.32kg·m^-3.The pre-anthesis nitrogen accumulation accounted for the total nitrogen absorption of the whole plant.The amount of about 60%,therefore,water and nitrogen before flowering is of great significance for nitrogen utilization efficiency.The above results indicate that the water-nitrogen coupling effect significantly affected the plant height,leaf area,photosynthetic rate,cell membrane antioxidant capacity,yield,and nitrogen use efficiency of winter wheat;meanwhile,W3N2 was selected(4500 m³·hm^-2,207 kg·hm^-2)The combination of water and nitrogen is the best matching mode,which provides a reference for the production of drip irrigation wheat in this area.