Effects Of Micro-sptinkler Irrigation And Nitrogen Regulation On Water And Nitrogen Use Efficiencies And Canopy Microenvironment Of Winter Wheat

Micro-irrigation isa technology of highly efficient water-saving,combined with theappropriate nitrogen levels,which is the effective measure to development the efficient use of water and nitrogen in winter wheat.A field experiment was carried out with the cultivar of Zhoumai 22 and Aikang 58 during 2015-2016.In this studiedthree nitrogen fertilizer levels and different micro-irrigation treatments were set up.The effects of micro-irrigation under different nitrogen fertilizers on the growth and development of winter wheat,the characteristics of water and nitrogen use and the yield traits were discussed.And the effect on wheat microenvironment was studied while micro-spray during the late grain filling stage.The main conclusions are as follows:1.The plant height and dry matter accumulation aboveground of winter wheat reached the maximum at maturity,and drip irrigation at jointing and anthesis stage could delay the decline of leaf area index.The plant height of Zhoumai 22 was higher than that of Aikang 58 under the same treatment.And the plant height and aboveground dry matter accumulation of both cultivars were obtained the highest value under N3 treatments which increased with the increase of irrigation amount.The leaf area index of Zhoumai 22 and Aikang 58 were the appropriate under N2W2 treatment,and which had stronger photosynthesis and dry matter production ability.2.The water consumption in the whole growth period wasincreased with the increase of nitrogen application rate and irrigation volume.At the same nitrogen level,the water consumption of W2 treatment was significantly higher than that of other treatments,and the peak value of water consumption gradually shifted with the increase of drip irrigation.There were significant differences in soil water consumption between different nitrogen fertilizer levels and water treatments.There was no significant difference in soil water consumption between Zhoumai 22 and Aikang 58 at N1 and N2,but higher than N3 level.The water consumption of W2 treated soil was the highest,which was significantly higher than W0 treatment,under the same nitrogen fertilizer.3.The water use efficiency was increased first and then decreased with the increase of irrigation amount,and decreased with the increase of nitrogen application rate.The efficiency of precipitation is W2>W1>W0,N2,N3>N1,the difference is significant(P<0.05).The water use efficiency of Zhoumai 22 and Aikang 58 were the highest under N2W1 treatment,and the utilization efficiency of precipitation was the highest under N2W2 treatment.4.Drip irrigation and nitrogen fertilizer regulation and their interaction had significant effects on plant nitrogen accumulation.At the same nitrogen level,the total nitrogen accumulation and grain nitrogen accumulation increased with the increase of irrigation amount,and obtained the highest under W2 treatment.The utilization rate of nitrogen in W2 was significantly higher than that in W1 for Zhoumai 22,but W1 treatment was significantly higher than W2 treatment for Aikang 58.Under the same water treatment,the nitrogen use efficiency and nitrogen harvest index decreased with the increase of nitrogen application level.The nitrogen translocation of vegetative organs in Zhoumai 22 and Aikang 58 was the highest at N2W2 and N3W1,respectively.5.The results showed that the micro-sprinklerirrigation 10 mm in the late grainfilling could significantly reduce the canopy temperature and CO2 concentration of winter wheat,and the flag leaf water potential and the relative humidity at canopy,30 cm and 60 cm bellow spikes significantly increased.In the high temperature period of 12: 00-16: 00,the canopy microenvironment under N2W2 treatment was better than other treatments,and the leaf water potential under N2W2 treatment was significantly higher 0.13-1.16 MPa than that of other treatments in the next day after spray.The correlation analysis showed that the yield was positively correlated with the relative humidity of the canopy,and there was a significant positive correlation with the water potential of flag leaf,which was negatively correlated with canopy temperature and canopy CO2 concentration,but the difference was not significant.In summary,under the nitrogen application 240 kg·hm-2,and drip irrigation at the sowing,jointing and anthesis stage,with micro-sprinklerirrigation 10 mm in the late grainfilling,Zhoumai 22,and Aikang 58 could obtain the highest yield of 6684.71 and 6952.39 kg·hm-2 respectively,and get the appropriate water and nitrogen use efficiency.