Tamanho de unidades experimentais básicas e tamanho ótimo de parcelas para nabo-forrageiro

Abstract

Resumo -O objetivo deste trabalho foi verificar a influência do tamanho da unidade experimental básica (UEB) sobre a estimativa do tamanho ótimo de parcela para a avaliação da massa de matéria fresca de nabo-forrageiro (Raphanus sativus). Dados de massa de matéria fresca de 3.456 unidades experimentais básicas de 0,5×0,5 m (0,25 m 2 ) foram utilizados, tendo-se formado 36 planos de UEBs com tamanhos entre 0,25 e 16 m 2 . Para cada plano de UEB, determinou-se o tamanho ótimo de parcela, pelo método da curvatura máxima do modelo do coeficiente de variação. A diferença mínima significativa pelo teste de Tukey foi calculada para 2.016 cenários, formados pelas combinações entre 36 tamanhos ótimos de parcela -um para cada plano de UEB -, i tratamentos (i = 5, 10, 15 e 20) e r repetições (r = 3, 4, 5, 6, 10, 15 e 20), tendo-se considerado tanto os delineamentos inteiramente casualizados como os de blocos ao acaso. O tamanho ótimo de parcela depende do tamanho da unidade experimental básica. Em ensaios de uniformidade com nabo-forrageiro, a avaliação da massa de matéria fresca deve ser feita em unidades experimentais básicas com o menor tamanho possível.Termos para indexação: Raphanus sativus, diferença mínima significativa, ensaio de uniformidade, planejamento experimental, plantios de cobertura, precisão experimental. Basic experimental unit size and optimum plot size for forage turnipAbstract -The objective of this work was to determine the effect of the basic experimental unit size (BEU) on the optimum plot size estimation for the evaluation of forage turnip (Raphanus sativus) fresh matter weight. Data from fresh matter weight of 3,456 BEUs of 0.5×0.5 m (0.25 m 2 ) were used, and 36 BEU plans, with sizes from 0.25 to 16 m 2 , were formed. For each BEU plan, the optimum plot size was determined by the method of maximum curvature of the coefficient of variation model. The least significant difference was calculated by Tukey's test in 2,016 scenarios formed by the combinations of 36 optimum plot sizes (one for each BEU plan), i treatments (i = 5, 10, 15, and 20), and r replicates (r = 3, 4, 5, 6, 10, 15, and 20), considering both the completely randomized designs and the complete block ones. Optimum plot size depends on the size of the basic experimental unit. In uniformity trials with forage turnip, the evaluation of fresh matter weight should be done in basic experimental units with the smallest possible size.

Optimal plot size for experimental trials with Opuntia cactus pear

“…With this practice, it is possible to achieve greater experimental efficiency in the detection of percentage differences between treatments with smaller plots and greater number of replications, instead of larger plots and fewer replicates (Sousa et al, 2016). Cargnelutti Filho et al (2016) argue that the increase in number of replicates is effective to enhance experimental accuracy, provided that the soil heterogeneity index (b < 0.2) is observed.…”

“…These studies, despite the relevance to the semi-arid region, reveal some disagreements on the experimental arrangement, number of replications and size of the experimental unit used (Queiroz et al, 2015;Silva et al, 2016). Thus, it is necessary to improve the agricultural research with cactus pear in order to obtain information on the number of replications, size and shape of the experimental plots to achieve results that allow detecting significant differences between tested treatments (Cargnelutti Filho, Storck, Lúcio, Toebe, & Alves, 2016;Cargnelutti Filho, Araujo, Gasparin, & Foltz, 2018).…”

“…The ideal size of the experimental plot can be established considering soil heterogeneity index -SHI (Smith, 1938;Cargnelutti Filho et al, 2016), genetic material or studied crop (Sousa, Silva, & Assis, 2016), balance between accuracy and costs (Cargnelutti Filho et al, 2016;Sousa et al, 2016), nature of the experimental material, number of replicates and evaluation methods (Cargnelutti Filho et al, 2018).…”

Basic experimental unit and plot sizes for fresh matter of sunn hemp

“…The authors concluded that the optimum plot size estimated using the method of maximum curvature of coefficient of variation model (PARANAÍBA et al, 2009) depends on the size of the BEU and that, with the addition of BEU size (X, BEU), there was a reduction in the optimum plot size in BEU (Xo, in BEU), with the power model pattern. Similarly, for the estimation of the Paranaíba method for white lupine (CARGNELUTTI FILHO et al, 2016b) and forage turnip (CARGNELUTTI FILHO et al, 2016a), the addition of BEU size (X, BEU) promotes a reduction in optimum plot size (Xo, in BEU), with the power model pattern.…”

“…Studies on the influence of BEU size on the estimation of optimum plot size, obtained by the method of maximum curvature of coefficient of variation model (PARANAÍBA et al, 2009), were developed to evaluate the fresh matter of white lupine (CARGNELUTTI FILHO et al, 2016b), forage turnip (CARGNELUTTI FILHO et al, 2016a), and sunn hemp (FACCO et al, 2017). These studies demonstrated that, for this method and these crops, the estimation of the optimum plot size depends on the BEU size.…”