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利用便携式光谱辐射仪测定了温室番茄叶片的光谱反射率,研究了不同施氮水平下特定光谱指数与叶片氮含量、光合速率及产量的关系。结果表明,温室番茄叶片的光谱反射率在可见光波段随供氮水平的升高而降低,在近红外波段随供氮水平的升高而增加。随施氮水平的提高,绿峰的蓝移和红边的红移现象明显,而红谷反射率与光合速率之间的关系可用二次方程拟合,相关系数达0.805。番茄叶片氮含量的敏感光谱波段为580~695 nm,740~900 nm,由695 nm、770 nm两个波段构建的高光谱指数(RVI、NDVI)与叶片氮含量的相关性显著。而基于原始光谱数据对番茄产量的估测也可在温室中得到很好的运用,其中光谱指数RV(I710,680)、VARI700和产量的拟合方程最优。
The spectral reflectance of greenhouse tomato leaves was measured by portable spectroradiometer and the relationship between specific spectral indices and nitrogen content, photosynthetic rate and yield under different nitrogen application levels was studied. The results showed that the spectral reflectance of greenhouse tomato leaves decreased with the increase of nitrogen supply in the visible light range and increased with the increase of nitrogen supply in the near infrared range. With the increase of nitrogen application, the blue shift of red and the red shift of red edge are obvious. The relationship between red valley reflectivity and photosynthetic rate can be fitted by quadratic equation with the correlation coefficient of 0.805. The sensitive spectral bands of nitrogen content in tomato leaves ranged from 580 to 695 nm and 740 to 900 nm. The correlation between hyperspectral index (RVI, NDVI) and leaf nitrogen content was significant at 695 nm and 770 nm bands. The estimation of tomato yield based on the original spectral data can also be well used in the greenhouse. The fitting equation of spectral index RV (I710, 680), VARI700 and yield is the best.