Sample Size for Height and Diameter Evaluation of Timbauva Plants

ABSTRACT The objective was to estimate the sample size to evaluate height (H), collar diameter (D) and relation height/collar diameter (HD) of timbauva plants (Enterolobium contortisiliquum) and to verify its variability among tubes, dosages of fertilizer and ages of evaluation. Ten treatments were organized in blocks designed with four replication and formed by the combination of sizes of tubes (110 and 180 cm3) and dosages of fertilizer (0, 3, 5, 7 e 9 g L-1 of substrate). The H, D and HD variables were evaluated in five ages. The sample size to evaluate H, D and HD is dependent on age evaluation. For the tubes, dosages of fertilizer and ages of evaluation, 22 plants per experimental unit (pot) are enough to predict the plants variables, with estimation error equal to 10% of estimated average, with a reliable rating of 95%.