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研究测定了不同品种夏玉米在六个典型生育期地上部分全氮、叶绿素含量、干生物量、叶面积指数(LAI)以及冠层光谱反射率,利用不同方法比较了不同品种玉米光谱特征的差异,系统分析了单波段反射率、可见光和近红外波段组合而成的8种常见植被指数与相应时期不同农学参量的相关性。结果表明:不同品种夏玉整个生育期不同品种冠层在可见光范围内反射率差异一直没有达到显著水平,苗期和拔节期在近红外区域反射率也无显著差异,从孕穗期到乳熟期在近红外区域反射率差异增大,普遍呈显著性差异。采用F检验法可以准确地反映不同品种在不同波段反射率的差异。常见光谱植被指数从拔节期到孕穗期绝大部分都可以准确反映不同品种夏玉米的农学参量,以GRVI最佳,它不仅可以区分不同品种夏玉米在中后期的长势,又可以准确拟合这段时期作物的农学参量。
The changes of total nitrogen, chlorophyll content, dry biomass, leaf area index (LAI) and canopy spectral reflectance of different summer maize cultivars in six typical growing stages were measured. The spectral characteristics of different maize varieties were compared by different methods The correlations of eight common vegetation indices combined with single-band reflectance, visible and near-infrared bands with different agronomic parameters of the corresponding period were systematically analyzed. The results showed that there was no significant difference in the reflectance of the canopy in different varieties throughout the growth period in the visible light range, no significant difference in the near-infrared reflectance at the seedling stage and the jointing stage, from the booting stage to the milk stage Reflectance differences in the near infrared region increased, the general significant difference. F-test method can accurately reflect the different varieties of reflectivity differences in different bands. The common spectral vegetation index can most accurately reflect the agronomic parameters of different varieties of summer maize from the jointing stage to the booting stage. The GRVI is the best one. It can not only distinguish the growth of different varieties of summer maize in the middle and late stages, but also fit accurately Agronomic parameters of crops during the period.