Tamanho de ensaio de uniformidade para estimação do tamanho de parcela em hortaliças

Abstract

The aim of this work were determine the optimum plot size and the uniformity assay size for estimating the optimum plot size in order to evaluate the fresh fitomass of lettuce plants and the mass of fruits of pepper, tomato, snap bean and zucchini. Production data were collected in uniformity assay with lettuce, pepper, tomato, snap bean and zucchini conducted at the Departamento de Fitotecnia da Universidade Federal de Santa Maria. Inside the planting row were planned different uniformity assay sizes. For each uniformity assay size planned were performed 3.000 resamples with replacement and were estimated for each sample the coefficient of spatial autocorrelation of the first order (p), the variance (s2), the mean (m) and the optimum plot size (Xo) by the method of maximum curvature of the coefficient of variation model (CMCV). Posteriorly, were also calculated the minimum values, percentile 2,5%, mean, percentile 97,5% and maximum values of statistics p, s2, m and Xo. For Xo statistic, even was calculated the amplitude of the confidence interval of 95%. Finally, were determined the uniformity assay size, starting from the smaller uniformity assay size planned (three basic units) and considering as uniformity assay size the number of basic units from which the amplitude of the confidence interval of 95% of optimum plot size was minor or equal to two basic experimental units. The uniformity assay size influences the estimation of the optimum plot size for evaluate the fresh fitomass of lettuce plants and the mass of pepper, tomato, snap bean and zucchini fruits. Uniformity assay with 27 basic units (27 plants) are enough for estimate the optimum plot size for evaluate the fresh fitomass of lettuce plants with a confidence interval of 95% minor or equal to two basic experimental units. Uniformity assay with pepper with 29 basic units (29 plants) in plastic greenhouse, with tomato with 12 basic units (12 plants) in plastic tunnel and with snap bean with 21 basic units (42 plants) in plastic tunnel, are enough for estimate the optimum plot size for evaluate the mass of fruits with a confidence interval of 95% minor or equal to two basic experimental units. Uniformity assay with snap bean with 18 basic units (36 plants) and with zucchini with ten basic units (ten plants) in plastic greenhouse are enough for estimate the optimum plot size for evaluate the mass of fruits with a confidence interval of 95% minor or equal to three basic experimental units. It is recommended the use of parcels with six basic experimental units for evaluate the fresh fitomass of lettuce plants and parcels with seven, five, six and eight basic experimental units, respectively, for evaluate the mass of fruits of pepper, tomato, snap bean and zucchini.