EVALUATION AND INTERPRETATION OF THEMATIC MAPPER RATIOS IN EQUATIONS FOR ESTIMATING CORN GROWTH-PARAMETERS

Reflectance and agronomic data were analyzed to determine possible data transformations for evaluating several plant parameters of corn. Three transformation forms were used: the ratio of two bands, logarithms of two-band ratios, and normalized differences of two bands. Normalized differences and logarithms of two-band ratios responded similarly in the equations for estimating the plant growth parameters evaluated in this study. Two-term equations were required to obtain the maximum predictability of percent ground cover, canopy moisture content, and total wet phytomass. Standard error of estimate values were 15-26% lower for two-term estimates of these parameters than for one-term estimates.