THEMATIC MAPPER VEGETATION INDEXES FOR DETERMINING SOYBEAN AND CORN GROWTH-PARAMETERS

The use of thematic mapper data to study crop growth parameters has pr imarily been conducted with hand-held and truck-mounted radiometers. I n addition, most studies have not used mid-infrared bands to develop v egetation indices. This study used Landsat thematic mapper data and cr op parameter data from corn and soybean fields in northern Ohio (1) to develop plant-water sensitive vegetation indices that included the mi d-infrared, near-infrared, and red bands; and (2) to compare the abili ty of different vegetation indices to estimate crop yield, leaf area i ndex, wet biomass, dry biomass, and plant height. Indices which includ ed the mid-infrared thematic mapper bands 5 and 7 performed equal to o r better than the widely used near-infrared band 4 and red band 3. The best relationships between vegetation indices and crop parameters had Spearman non-parametric correlation coefficients of 0.80 to 0.89 for all parameters except crop yield which was not highly correlated with the vegetation indices.