A Broad-Band Leaf Chlorophyll Estimator at the Canopy Scale for Variable Rate Nitrogen Fertilization

摘要

We have proposed an optimized version (OCVI) of the chlorophyll vegetation index (CVI), a broad-band VI specifically sensitive for planophile crops (i.e. with low average leaf angle) to leaf chlorophyll concentration at the canopy scale. A single correction factor is incorporated in the OCVI algorithm to take into account the different spectral behaviours due to crop and soil types, sensor spectral resolution and scene sun zenith angle. Prior knowledge of the soil spectral behaviour is critical to a proper determination of the correction factor. By analyzing a large SAILH+PROSPECT synthetic dataset, the present work addresses the use of the slope of the green-red soil line as a practical indicator of the soil spectral behaviour for the estimation of the correction factor.