ON THE INFORMATION-CONTENT OF SOIL REFLECTANCE SPECTRA

High resolution (.01 μm) reflectance spectra from more than 500 soils are analyzed to determine spectral variability in a portion of the visible and near infrared (0.55-2.32 μm), using a procedure previously developed for study of thermal infrared spectra. Four high spectral resolution basis vectors are sufficient to describe 99.6% of the spectral variability of the data set, with residual variability probably associated with the measurement process and instrument noise. Four broadband spectral measurements at .93-1.13 μm, 2.03-2.31 μm, .63-.74 μm, and 1.61-1.80 μm, together with a priori knowledge of the fitting vectors, are sufficient to describe the spectra of the soils studied. © 1990.