Remote estimation of chlorophyll content in higher plant leaves

Indices for the non-destructive estimation of chlorophyll content were formulated using various instruments to measure reflectance and absorption spectra in visible and near-infrared ranges, as well as chlorophyll contents from several non-related species from different climatic regions. The proposed new algorithms are simple ratios between percentage reflectance at spectral regions that are highly sensitive (540 to 630 nm and around 700 nm) and insensitive (near-infrared) to variations in chlorophyll content: R-NIR/R-700 and R-NIR/R-550. The developed algorithms predicting leaf chemistry from the leaf optics were validated for nine plant species in the range of chlorophyll content from 0.27 to 62.9 mu g cm(-2). An error of less than 4.2 mu g cm(-2) in chlorophyll prediction was achieved. The use of green and red (near 700 nm) channels increases the sensitivity of NDVI to chlorophyll content by about five-fold.