Satellite remote sensing of three wheat and bean agronomic parameters

Abstract

In this work a single TM4 band and two spectral indexes - ratio TM4/TM3 and perpendicular vegetation index — were studied. Spectral digital counts obtained from TM/Landsat-5 tapes were corrected for radiometric and atmospheric effects. Wheat and bean agronomic parameters were green leaf area index, percent soil cover and chlorophyll density. These agronomic data were collected over commercial plantations on 1986 winter. Discussion of results were carried out on physical and physiological bases. It is showed that there are good relationships between satellite spectral parameters and agronomic parameters for both wheat and bean. The possibility of estimating the vigor conditions of an agricultural field from orbital data was stressed. Nevertheless, in some point of the growing season the agronomic parameters reach values so high that their relationships with spectral parameters become asymptotic rather than linear, which would be the ideal situation. PVI, as expected, was powerful to minimize the effect of underlying tropical soils on crops spectral responses.