RESUMO Os objetivos deste trabalho foram determinar o tamanho ótimo de parcela e o número de repetições, para avaliar a massa verde de aveia preta (Avena strigosa Schreb

Tamanho de amostra para a estimação da média do comprimento, diâmetro e massa de sementes de feijão de porco... Ciência Rural, v.42, n.9, set, 2012. Ciência Rural, Santa Maria, v.42, n.9, p.1541-1544, set, 2012 ISSN 0103-8478 As espécies leguminosas possuem capacidade de fixação biológica de nitrogênio e ciclagem de nutrientes, sendo utilizadas no sistema de rotação de culturas. Segundo TEODORO et al. (2011), as culturas de feijão de porco e de mucuna cinza estão entre as espécies leguminosas mais promissoras para a adubação verde, devido à elevada produção de matéria seca. Além disso, TEODORO et al. (2011)

RESUMO O objetivo deste trabalho foi determinar o tamanho de amostra (número de plantas) para a estimação da média de caracteres morfológicos e produtivos de nabo forrageiro (Raphanus sativus L.). Em um experimento a campo, foramselecionadas, aleatoriamente, 300 plantas e mensurados os caracteres morfológicos (estatura de planta e número de folhas aos 21, 35, 48, 55, 62, 70, 77 21, 35, 48, 55, 62, 70, 77 ABSTRACT The aim of this research was to determine the sample size to estimate the average of morphological and productive traits of turnip (Raphanus sativus L.). In a experiment, 300 plants were randomly selected and measured for morphological traits (plant height and number of leaf at

Resumo -O objetivo deste trabalho foi determinar a precisão experimental na avaliação da massa de matéria verde de nabo forrageiro, em cenários formados por combinações de tamanhos de parcela e número de tratamentos e de repetições. Utilizaram-se os dados de massa de matéria verde de 3.456 unidades experimentais básicas de 0,5×0,5 m (0,25 m 2 ). Os cenários (1.728) foram planejados e formados pela combinação de seis tamanhos de parcela (0,25, 0,50, 1,00, 1,50, 2,00 e 2,25 m 2 ), i tratamentos (i = 5, 6,..., 20) e r repetições (r = 3, 4,..., 20). Em cada cenário, foram realizadas 2.000 reamostragens, com reposição. Calculou-se a média das 2.000 estimativas, em cada cenário, quanto à diferença mínima significativa pelo teste de Tukey, ao índice de variação e ao coeficiente de variação experimental. Essas estatísticas, nesta ordem, são adequadas para avaliar a precisão experimental. Parcelas com o tamanho de seis unidades experimentais básicas (1,50 m 2 ) são suficientes para identificar diferenças significativas na massa de matéria verde de nabo forrageiro entre tratamentos, menores ou iguais a 36,88% da média geral do experimento, pelo teste de Tukey, a 5% de probabilidade, em experimentos em delineamento inteiramente casualizado, com 5 a 20 tratamentos e cinco repetições.Termos para indexação: Raphanus sativus, coeficiente de variação, diferença mínima significativa, índice de variação, planejamento experimental, reamostragem. Experimental precision related to plot sizes, numbers of treatments and replicates in forage turnipAbstract -The objective of this work was to determine the experimental precision in the evaluation of forage turnip fresh matter weight, in scenarios formed by combinations of plot sizes and number of treatments and replicates. Data from fresh matter weight of 3,456 basic experimental units of 0.5×0.5 m (0.25 m 2 ) were used. The scenarios (1,728) were planned and formed by the combinations of six plot sizes (0.25, 0.50, 1.00, 1.50, 2.00, and 2.25 m 2 ), i treatments (i = 5, 6,..., 20), and r replicates (r = 3, 4,..., 20). For each scenario, 2,000 resamplings were carried out, with replacement. The average of these 2,000 estimates, in each scenario, was calculated for the least significant difference by Tukey's test, the variation index, and the experimental coefficient of variation. These statistics, in that order, are adequate to evaluate the experimental precision. Plots with the size of six basic experimental units (1.50 m 2 ) are sufficient to identify significant differences turnip fresh matter weight between treatments, less than or equal to 36.88% of the overall mean of the experiment, by Tukey's test, at 5% probability, in experiments in a completely randomized design with 5 to 20 treatments and five replicates.

The influence of the basic experimental unit size on the plot size estimation determined by the method of maximum curvature of the coefficient of variation model is unknown in sunn hemp. This study aimed to verify the influence of the basic experimental unit (BEU) size in the estimate of the optimum plot size obtained by the method of maximum curvature of the coefficient of variation model for the evaluation of fresh matter of sunn hemp (Crotalaria juncea L.). Fresh matter of sunn hemp at the flowering was evaluated in uniformity trials in two sowing dates. In each sowing date, 4,608 BEU of 0.5 × 0.5 m (0.25 m 2 ) were evaluated and 64 BEU plans were formed with sizes from 0.25 to 64 m 2 . In each evaluation period for each BEU plan, the first order spatial autocorrelation coefficient, variance, standard deviation, mean, coefficient of variation of the trial and the plot size were determined with the fresh matter data. For each BEU plan, the optimum plot size was determined by the method of maximum curvature of the coefficient of variation model. The estimate of optimum plot size depends on the basic experimental unit size. Determining the plot size to assess the fresh matter in basic experimental units as small as possible is recommended in order to prevent overestimation of the plot size and to contemplate all existing variability.Key words: Crotalaria juncea L., experimental design, basic experimental unit. INTRODUCTIONThe sunn hemp (Crotalaria juncea L.) is a cover crop option for soil protection due to its hardiness, high dry matter production and nitrogen fixation (Silva and Menezes, 2007), improving and maintaining soil quality, raising to considerable levels of soil organic matter and nutrients (Leite et al., 2010). The crop rapid development enables the use of sunn hemp in cropping systems with rotation and crop succession. It is the legume with greatest dry matter production in comparison with gray velvet bean (Mucuna nivea), jack bean (Canavalia ensiformis), velvet bean (Mucuna aterrina), lab-lab (Dolichos lablab), showy crotalaria (Crotalaria spectabilis), and dwarf pigeon pea (Cajanus cajan) (Teodoro et al., 2011); in a study carried out by Andrade Neto et al. (2010), the fresh matter of aerial part values of sunn hemp were 13.9 t ha -1 . One aspect to be considered is the inferences made in agricultural research representing experimental reality which is the use of an optimum plot size to minimize the experimental error. The optimum plot size can be calculated based on data obtained from uniformity trials in which treatments are not applied (Ramalho et al., 2012;Storck et al., 2016). In order to evaluate traits of the studied crop, the experimental area is divided into basic experimental units (BEU) with the smallest possible size. Therefore, based on this information, the plot size is determined.The influence of the BEU size in estimating the optimum plot size is still an area with few studies but Oliveira et al. (2005) verified in potato (Solanum tuberosum L.) the BEU size effect on the optimum p...

This study aimed to verify the influence of the basic experimental unit (BEU) size in the estimation of the optimum plot size to evaluate the fresh matter of sunn hemp (Crotalaria juncea L.) using the modified maximum curvature method. The fresh matter of sunn hemp was evaluated in uniformity trials in two sowing season in flowering. In each sowing season, 4,608 BEUs of 0.5×0.5m (0.25m2) were evaluated and 36 BEU plans were formed with sizes from 0.25 to 16m2. In each evaluation period for each BEU plan, using fresh matter data, optimum plot size was estimated through the modified maximum curvature method. Estimation of the optimum plot size depends on the BEU size. Assessing fresh matter in BEUs that are as small as possible is recommended in order to use it to estimate the optimum plot size.

The objectives of this study were to determine the sample size (i.e., number of plants) required to accurately estimate the average of morphological traits of pigeonpea (Cajanus cajan L.) and to check for variability in sample size between evaluation periods and seasons. Two uniformity trials (i.e., experiments without treatment) were conducted for two growing seasons. In the first season (2011/2012), the seeds were sown by broadcast seeding, and in the second season (2012/2013), the seeds were sown in rows spaced 0.50 m apart. The ground area in each experiment was 1,848 m 2 , and 360 plants were marked in the central area, in a 2 m × 2 m grid. Three morphological traits (e.g., number of nodes, plant height and stem diameter) were evaluated 13 times during the first season and 22 times in the second season. Measurements for all three morphological traits were normally distributed and confirmed through the Kolmogorov-Smirnov test. Randomness was confirmed using the Run Test, and the descriptive statistics were calculated. For each trait, the sample size (n) was calculated for the semiamplitudes of the confidence interval (i.e., estimation error) equal to 2, 4, 6, ..., 20% of the estimated mean with a confidence coefficient (1-α) of 95%. Subsequently, n was fixed at 360 plants, and the estimation error of the estimated percentage of the average for each trait was calculated. Variability of the sample size for the pigeonpea culture was observed between the morphological traits evaluated, among the evaluation periods and between seasons. Therefore, to assess with an accuracy of 6% of the estimated average, at least 136 plants must be evaluated throughout the pigeonpea crop cycle to determine the sample size for the traits (e.g., number of nodes, plant height and stem diameter) in the different evaluation periods and between seasons. Key words: Cajanus cajan L., sample dimensioning, experimental precision ResumoOs objetivos deste estudo foram determinar o tamanho de amostra (número de plantas) para estimação da média de caracteres morfológicos de feijão guandu (Cajanus cajan L.) e verificar se há variabilidade do tamanho de amostra entre as épocas de avaliação e entre os anos agrícolas. ensaios de uniformidade (experimentos sem tratamentos), em dois anos agrícolas. No primeiro ano agrícola (2011/2012), a semeadura foi realizada a lanço e no segundo ano agrícola (2012/2013), a semeadura foi realizada em linhas espaçadas a 0,50 m. A área útil, em cada um dos experimentos foi de 1.848 m 2 , e foram demarcadas 360 plantas, na área central, em um gride de 2 m × 2 m. Foram avaliados três caracteres morfológicos (número de nós, altura de planta e diâmetro de caule) em 13 épocas no primeiro ano agrícola e em 22 épocas no segundo ano agrícola. Em todos os caracteres foi verificada a normalidade, por meio do teste de Kolmogorov-Smirnov e a aleatoriedade pelo Run Test e calculadas as estatísticas descritivas. Para cada caractere, foi calculado o tamanho de amostra (n), para as semiamplitudes do intervalo de confiança (...

RESUMO Os objetivos deste trabalho foram determinar o tamanho de amostra (número de plantas) para a estimação da média de caracteres morfológicos e produtivos de aveia preta (Avena strigosa Schreb) e verifi car a variabilidade do tamanhode amostra entre caracteres e entre épocas de avaliação. Num experimento a campo, em dez épocas de avaliação (22, 28, 34, 42, 48, 55, 76, 83, 90 (22, 28, 34, 42, 48, 55, 76, 83, 90 and Em experimentos com culturas agrícolas, como aveia preta (Avena strigosa Schreb), ao avaliar um caractere em uma época, é comum constatar variabilidade entre as plantas, mesmo naquelas submetidas ao mesmo tratamento. O correto dimensionamento amostral é fundamental para a obtenção de informações fi dedignas do caractere em avaliação. Estudos indicam variabilidade do tamanho de amostra entre caracteres e também para o mesmo caractere, entre as épocas de avaliação. Na cultura de crambe, CARGNELUTTI FILHO et al. (2010) verifi caram que o tamanho de amostra para a estimação da média dos caracteres produtivos é maior que o dos morfológicos. Ainda em crambe, para a -NOTA -I days after sowing) were randomly selected 52 plants, totaling 520 plants. In each plant, were measured morphological (plant height, number of leaves and number of tillers) and productive characters (fresh and dry matters). Measures of central tendency