Estimation of optimal size of plots for experiments with radiometer in beans

An experimental error can lead to rework and, consequently, to the loss of financial and human resources. One way to reduce this problem is the estimation of the optimum size of experimental plot to carry out the treatments. The objective of this study was to estimate the optimal size of plots for reflectance measurements in beans by the modified maximum curvature method and the maximum distance method. Reflectance readings were made on bean plants with the aid of the GreenSeeker® equipment, obtaining basic units of 0.45 m² in an area of lines 6 and 8 m in length, performing 46 combinations of experimental area. X0 was determined using the modified maximum curvature and the maximum distance method. To increase the R², the calculations have been redone using 20 combinations of experimental area. By adopting the bigest obtained area, it was concluded that the optimum size of an experimental plot for works with reflectance in beans is 5.40 m² and the combination that presents the best distribution is 2 lines totalling 6 m long.   Key words: Reflectance, experimental error, modified maximum curvature, maximum distance.