不同玉米品种氮胁迫响应及诊断参数确定

Responses of Different Maize Varieties to Nitrogen Stress and Determination of Diagnostic Parameters

本研究以两个不同玉米品种(冀玉5817和郑单958)为研究对象,同步获取其关键功能叶片(玉米生育前期为最上部完全展开叶、吐丝后为穗位叶)氮含量和光谱反射率,分析不同施氮水平下两个品种关键功能叶片氮含量的响应特征和产量反应。研究表明,不同品种在整个生育期的叶片氮含量的变化整体趋势一致,两个玉米品种最优氮处理均为180 kg/hm^(2),冀玉5817氮含量在成熟期之前普遍高于郑单958,两个品种对不同氮处理响应有所差异。本研究建立基于优化处理的氮素丰缺诊断指标,即氮胁迫指数(NSI)和氮胁迫光谱指数(NSSI)。基于光谱参数NVI(570,670)构建的NSSI对缺氮响应比较敏感,并且对两个品种均适用。该方法及其构建的参数通过与同条件下优化处理进行比较,避免了氮素营养的光谱诊断受品种和生育期的影响,并且光谱参数可实时、快速和无损地获取,为玉米生育期内氮肥的优化调控提供了依据。

In this study,two different maize varieties(Jiyu5817 and Zhengdan958)were selected as the re⁃search objects,and the N content and spectral reflectance of their key functional leaves(the top fully expanded leaf at the early growth stage and the ear leaf after silking)were simultaneously obtained.The response characteristics of N content in key functional leaves and yield response of two varieties under different N application levels were ana⁃lyzed.The results showed that the change trend of leaf N content of different varieties in the whole growth period was similar.The optimal N treatment of the two maize varieties was 180 kg/ha,but the N content of Jiyu5817 was generally higher than that of Zhengdan958 before maturity,and the response of the two varieties to different N treat⁃ments was also different.The nitrogen stress index(NSI)and the nitrogen stress spectral index(NSSI)were estab⁃lished based on the optimized treatment.Among them,NSSI calculated by spectral parameter NVI(570,670)was sensitive to N deficiency and suitable for both cultivars.Compared with the optimized treatment under the same con⁃ditions,the method and its parameters can avoid the influence of variety and growth period on the N spectral diagno⁃sis,and the spectral parameters can be obtained in real time,quickly and nondestructively,which provides a basis for the optimal regulation of N fertilizer in the growth period of maize.