不同氮处理春玉米叶片光谱反射率与叶片全氮和叶绿素含量的相关研究

Correlation Between Corn Leaf Spectral Reflectance and Leaf Total Nitrogen and Chlorophyll Content Under Different Nitrogen Level

采用盆栽试验研究了不同氮营养水平下的春玉米叶片叶绿素和全氮含量与叶片光谱反射率的相关性。结果表明,拔节期和喇叭口期是玉米氮素光谱营养诊断的敏感时期;利用绿峰处叶片最大光谱反射率反演玉米叶片氮素含量和叶绿素含量的精度为:喇叭口期>拔节期>开花吐丝期;不同生育时期诊断玉米叶片氮素含量和叶绿素含量时所采用的光谱波段也不同,拔节期和喇叭口期采用可见光波段的光谱反射率可靠性较高,而开花吐丝期采用近红外波段的光谱反射率可靠性较高;两波段组合光谱变量对叶片叶绿素和全氮含量的判别精度高于单一波段的判别精度。

The correlation between the corn leaf chlorophyll content, total nitrogen content, moisture content and leaf spectral reflectance was studied in a patted experiment under different N treatments. Results showed that shooting stage and trumpet stage were sensitive stages for diagnosis of nitrogen in corn. The precision of inferring leaf nitrogen and chlorophyll concentration by leaves maximal spectral reflectance at green waveband was： trumpet stage 〉 shooting stage 〉 anthesis-silking stage. Different wavebands should be chosed for diagnosis of corn leaf nitrogen and chlorophyll concentration in different development stages. It was proved that the reliability of using visible spectral reflectance was preferable than other wavebands at shooting stage and trumpet, but near infrared spectral reflectance was more reliable at anthesis-silking stage. The combination spectra variables of two wave bands were better than single wave band to estimate the content of leaf total nitrogen and chlorophyll.