新疆塔额盆地滴灌冬小麦氮营养诊断研究

Nitrogen nutrition diagnosis for drip-irrigated winter wheat in Ta′e basin,Xinjiang

为实现塔额盆地滴灌冬小麦氮营养诊断、确定适宜施氮量,在2020—2021年开展了两年大田试验。试验以‘新冬18’为研究对象,共设5个氮肥水平(0、80、160、240和320 kg/hm^(2)),分析不同施氮量对小麦地上部生物量及植株氮浓度的影响,构建冬小麦临界氮浓度稀释曲线模型,并计算不同施氮量的植株氮营养指数,分析其与相对产量的关系,确定冬小麦氮营养丰缺情况。研究结果表明,冬小麦各生育时期,施氮量从0增加到240 kg/hm^(2),植株生物量及氮浓度差异显著,但当施氮量从240增加到320 kg/hm^(2)时,植株生物量及氮浓度差异不显著。施氮量与产量的拟合曲线表明,超过一定的施氮量后,增施氮肥会降低冬小麦产量,说明存在氮奢侈消费现象。依据地上部生物量与植株氮浓度构建的冬小麦临界氮浓度稀释曲线模型N_(c)=3.088DM^(-0.374),模型决定系数R^(2)=0.918,模型检验参数(标准化均方根误差,n-RMSE)为8.89%,模型稳定性极好。基于植株临界氮浓度计算的氮营养指数,冬小麦适宜施氮量为160~240 kg/hm^(2)。冬小麦各生育时期,氮营养指数与相对产量的相关性均达到显著水平。综上所述,建立的塔额盆地冬小麦临界氮浓度稀释曲线模型及氮营养指数可以较好地诊断并评价冬小麦氮营养状况。

To realize the nitrogen(N)nutrition diagnosis for drip-irrigated winter wheat in Ta′e basin and determine the appropriate nitrogen application rate,field experiments during 2020—2021 were conducted.In this study,the variety of‘Xindong 18’was selected,and five N application rates(0,80,160,240 and 320 kg/hm^(2))were set up.The effect of different N application rates on wheat aboveground biomass and plant N concentration were analyzed,and a critical N concentration model was developed.After then,the N nutrition index(NNI)of winter wheat under different N application rates were calculated,its relationship with relative yield was analyzed,and ultimately the N nutrition status of plant was determined.The results showed that at each growth stage of winter wheat,the difference of plant biomass and N concentration were significant when N application increased from 0 to 240 kg/hm^(2),while it was not significant when N application increased from 240 to 320 kg/hm^(2).The fitted curve between N application rate and yield showed that after a certain amount of N application,increasing N application would reduce the yield of winter wheat,indicating that there was a phenomenon of N extravagance consumption.The critical N concentration model of winter wheat based on aboveground biomass and N concentration was N_(c)=3.088DM^(-0.374),the determination coefficient R^(2)of the model was 0.918,and the test parameter n-RMSE was 8.89%,which indicted the high stability of the model.The NNI calculated based on the critical N concentration of plant indicated that the suitable N application rate for winter wheat was 160-240 kg/hm^(2).The correlationship between NNI and relative yield in each growth stage was significant.In conclusion,the developed critical N concentration model and NNI of winter wheat in Ta′e basin could better diagnose and evaluate the N nutrition of winter wheat.