Effects Of Nitrogen Rate On Growth And Lodging Resistance Of Spring Maize Under Drip Irrigation

【Object】The effects of nitrogen application rate on growth and lodging resistance of high-yielding spring maize under drip irrigation under film were studied.The response of maize plant traits,leaf area,dry matter accumulation characteristics,yield and lodging resistance to different nitrogen application rates were clarified.Under dense planting conditions,the characteristics of lodging resistance of maize stalks under the integration of water and fertilizer and nitrogen fertilizer application were clarified,which provided theoretical basis and technical reference for formulating a reasonable nitrogen application system for spring maize under drip irrigation.【Method】The trial will be conducted in Xinjiang Qitai Farm in 2019.The tested varieties were Xianyu335(XY335)and Denghai 618(DH618).The density was set to 7.5×10~4 plants/hm~2(D5)and 12.0×10~4plants/hm~2(D8).Planting mode.Irrigation and fertilization uses a drip irrigation system under the film.The experiment set 18 nitrogen application levels:0 kg/hm~2(N0),45 kg/hm~2(N45),90 kg/hm~2(N90),135 kg/hm~2(N135),180 kg/hm~2(N180),225 kg/hm~2(N225),270 kg/hm~2(N270),315 kg/hm~2(N315),360kg/hm~2(N360),405 kg/hm~2(N405),450 kg/hm~2(N450),495 kg/hm~2(N495),540 kg/hm~2(N540),585 kg/hm~2(N585),630 kg/hm~2(N630),675 kg/hm~2(N675),720 kg/hm~2(N720),765 kg/hm~2(N765).The effects of different nitrogen rates on the growth and development,yield and lodging resistance of spring maize under drip irrigation were analyzed.【Result】The amount of nitrogen applied had different effects on the growth and development of maize with different densities.Under the density of 7.5×10~4 plants/hm~2,the maximum yield of DH618 and XY335under the treatment of nitrogen application N315 was 17.8 t/hm~2 and 18.9 t/hm~2,respectively;while under the condition of 12.0×10~4 plants/hm~2 density,DH618 The highest yield under N405 treatment was 18.9 t/hm~2,while the highest yield under XY335 treatment was 19.3 t/hm~2.Within a certain nitrogen application range,as the nitrogen application rate increased,the maize stalk’s breaking resistance,interstitial puncture strength(RPS),and dry weight per unit length(DWUL)gradually increased.When the nitrogen application rate reached a certain level,Stem breaking resistance,RPS and DWUL at the base no longer increased.Maize plant height,ear height and ear position coefficient also increased with the increase of nitrogen application.Correlation analysis showed that the stem breaking resistance was significantly negatively correlated with plant height,ear height,and ear position coefficient,and significantly positively correlated with basal internode RPS and DWUL.【Conclusion】(1)Nitrogen application rate affects plant height and ear height of maize,affects leaf area and leaf area index of maize,and affects dry matter accumulation in maize.But when more nitrogen fertilizer is applied,the leaf area and dry matter will not increase.Appropriate amount of nitrogen is beneficial to the growth of leaf area and dry matter accumulation in maize.(2)Nitrogen application rate was significantly affects the number of ears and 1000-grain weight of maize.Too little nitrogen application is not conducive to the formation of maize grains,and thus affects the yield of maize.Variety DH618,under the conditions of density D5 and D8,the nitrogen application amount to obtain the highest yield was N315 and N405,and variety XY335,under the conditions of density D5 and D8,the nitrogen application amount to obtain the highest yield was N315 and N360,respectively.With the increase of the amount of nitrogen application,the output increased first and then stabilized,showing a linear plus platform model.(3)Variety,density and amount of nitrogen all have effects on the lodging characteristics of maize.Under the same management measures,the resistance of DH618 to fall was greater than XY335;the resistance to fall decreased with increasing density;as the amount of nitrogen applied increased,the breaking resistance of the maize stalk increased gradually.Stem breaking resistance no longer increases.Under the conditions of integrated water and fertilizer and nitrogen fertilizer application,increasing the amount of nitrogen application can improve the mechanical strength by increasing the dry matter accumulation in the maize stalk,thereby improving the lodging resistance of the stalk.