| The objective of this study was to evaluate the efficiency of the leaf disc method for estimating the leaf area index (LAI) of soybean plants in comparison with the digital photo method. A split-plot experimental design was used with three replications. The LAIs calculated by the leaf disc and digital photo methods were compared at four growth stages in four soybean cultivars (subplot). These soybean cultivars were sowed in Guarapuava, Paraná State, Brazil, at three different sowing dates (main plot) in the 2010/2011 growing season. Regression analysis was used for each group of samples, and the efficiency of the leaf disc method was evaluated on the basis of the coefficient of determination (R²), the calculated F and the intersection and abscissa errors.... |
