Effect Of Water And Nitrogen Coupling On High Yield And High Efficiency Of Winter Wheat

In order to understand the effect of water and nitrogen coupling on winter wheat high yield and high efficiency to provide the basis for the high yield and high efficiency cultivation,winter wheat varieties Hemai 901 is taken as experimental material.Based on the different water and nitrogen treatments under field experiment in 2014-2015,the effect of water and nitrogen coupling on wheat water and nitrogen utilization,photosynthetic characteristics,dry matter translocation and grain yield were analysed.The main research results are as follows: 1 The effect of water and nitrogen combination on water and nitrogen use efficiency of winter wheatUnder the condition of the maximum field moisture capacity 60%?W2?,the water and nitrogen production efficiency increased with increase of the amount of nitrogen fertilizer.Under the maximum field moisture capacity 80%?W3?,the water production efficiency firstly increased and then decreased nitrogen use efficiency decreased with increase of the amount of nitrogen fertilizer.Under the condition of natural precipitation?W1?,nitrogen use efficiency difference is not significant.Under the same nitrogen conditions,the water production efficiency decreased and nitrogen fertilizer production efficiency increased with the increase of irrigation amount.The experimental results showed that the irrigation efficiency and nitrogen production efficiency of W2N3 reached the highest value.Therefore,the maximum water holding capacity of 60%?W2?and nitrogen application rate in the field of 300 kg hm-2?W3?was the most beneficial to improve the efficiency of water and nitrogen fertilizer.2 The effect of water and nitrogen combination on photosynthetic characteristics of winter wheatThe results showed that the decline rate of flag leaf SPAD decreased with the increase of nitrogen fertilizer.The application of nitrogen fertilizer could significantly increase the SPAD value,which was beneficial to the photosynthesis of wheat.Nitrogen also can significantly increase the net photosynthetic rate?Pn?and stomatal conductance?Gs?,expressed as N3>N2>N1.Under the maximum field moisture capacity 60%?W2?and 80%?W3?,the transpiration rate?Tr?of flag leaf was N2>N3>N1.The effect of water on the flag leaf transpiration rate?Tr?was W2>W3>W1 and the water and fertilizer combination of largest Tr was W2N2.The intercellular CO₂ concentration?Ci?decreased with the increase of irrigation amount,and the trend of decrease with the increase of the amount of nitrogen application.Stomatal conductance?Gs?increased with the increase of irrigation amount.The results showed that N2W2,W3W2 and W3N2,W3N3,four water and nitrogen combination can maintain a higher SPAD value and net photosynthetic rate.3 Effect of water and nitrogen coupling on grain filling of winter wheatIncreasing nitrogen application rate could prolong the grain filling duration?T?,the grain filling duration was the longest?42 d?in W2N3 combination.The maximum filling rate?Rmax?and average grain filling rate?R?were under W2 treatment.Grain weight?Y?and grain filling duration?T?showed a very significant positive correlation.The test results show that the W2N3 is the best water and nitrogen combination for wheat grain filling.4 Effect of water and nitrogen coupling on dry matter accumulation and distribution of winter wheatNitrogen application and irrigation could increase the dry matter accumulation of wheat,which showed N3>N2>N1.The dry matter distribution in mature stage: grain > leaf+stem+sheath>cob+glume.Under higher water and nitrogen,W3N2 and W3N3 treatment,cob and glume dry matter distribution ratio was significantly higher than that of other treatments.That shows too much water and nitrogen fertilizer will reduce the grain dry matter accumulation.The results showed that under W2N2 and W2N3,amount of dry matter accumulation not only was large,but also proportion of grain distribution high.So W2N2 and W2N3 were the best combination of water and nitrogen for wheat production.5 Effect of water and nitrogen on wheat yield and its componentsOn yield components,water and nitrogen can improve ear number,grain number per spike.Grain number per spike was the highest?40.52?under W2N3 treatment.1000 grain weight increased with the increase of the amount of nitrogen fertilizer and the highest?42.64 g?under W2N1 treatment.Under the same irrigation condition,the yield increased with the increase of nitrogen application,show as N3>N2>N1.Under the same nitrogen application,the yield firstly increased and then decreased with the increase of irrigation amount,which showed that drought and excess water would decrease the yield of winter wheat.The experiment results show that W2N3 not only has the highest yield,9057.58 kg hm-2,but also highest water and nitrogen use efficiency.Therefore,the maximum field moisture capacity 60%?W2?and nitrogen application 300 kg.hm-2?N3?were the best water and nitrogen combination for high yield and high efficiency of winter wheat.So,according to the natural precipitation and soil nutrient supply,the appropriate water and nitrogen adjustments will be able to achieve the wheat high yield and high efficiency synchronous and agricultural sustainable production.