Plot size and number of replications for ryegrass experiments

Marcos Toebe,Francieli De Lima Tartaglia,Alessandra Ferreira Cortes,Alberto Cargnelutti Filho,Patrícia Jesus De Melo,Juliana Oliveira De Carvalho,Anderson Chuquel Mello

doi:10.1590/0103-8478cr20190195

Abstract

ABSTRACT: The objective of this research was to determine the optimal plot size and the number of replications to evaluate the fresh matter of ryegrass sown to haul. Twenty uniformity trials were conducted, each trial with 16 basic experimental units (BEU) of 0.5 m2. At 117, 118 and 119 days after sowing, the fresh matter of ryegrass in the BEUs of 5, 10 and 5 uniformity trials, respectively, were determined. The optimal plot size was determined by the maximum curvature method of the variation coefficient model. Next, the replications number was determined in scenarios formed by combinations of i treatments (i = 3, 4, ... 50) and d minimum differences between means of treatments to be detected as significant at 5% of probability by the Tukey test, expressed in experimental mean percentage (d = 10, 11, ... 20%). The optimal plot size to determine the fresh matter of ryegrass seeded at the haul is 2.19 m2, with a variation coefficient of 9.79%. To identify as significant at 5% probability, by the Tukey test, differences between treatment means of 20%, are required five, six, seven and eight replications, respectively, in ryegrass experiments with up to 5, 10, 20 and 50 treatments.

Highlights

The ryegrass (Lolium multiflorum L.) is the annual winter pasture with the largest cultivated area in the state of Rio Grande do Sul (Biscaíno et al, 2018)
At days after sowing (DAS), in ten trials at DAS and in five trials at DAS, in each basic experimental units (BEU), the plants were cut near the soil surface and the fresh matter weight determined in grams per 0.5 m
There were no differences between the three evaluation times for estimates of the first-order spatial autocorrelation coefficient (ρ), variance (s2), mean (m), variation coefficient of the trial (CVtrial), optimal plot size (Xo) and the variation coefficient in the optimal plot size (CVXo) of the fresh matter weight for ryegrass seeded on the haul (Table 1)

Summary

Introduction

The ryegrass (Lolium multiflorum L.) is the annual winter pasture with the largest cultivated area in the state of Rio Grande do Sul (Biscaíno et al, 2018). Ryegrass is an important forage used in dairy production, with ease natural reseeding, disease resistance, high seed production potential and versatility in intercropping (CASSOL et al, 2011). In this sense, dairy cows grazing ryegrass pasture, with a high forage allowance, can eat more than 16.0 kg dry matter/cow.day and produce more than 20 kg milk/ day (RIBEIRO FILHO et al, 2009). In ryegrass experiments, were used plots from four plants until plots with areas of 108 m2 and three to eight replications (FLORES et al, 2008; CASSOL et al, 2011; AGOSTINETTO et al, 2017; VIZIOLI et al, 2018). ; experimental planning has already been carried out for forage crops, such as oat (Cargnelutti Filho et al, 2014; Lavezo et al, 2017), forage pea (Cargnelutti Filho et al, 2015), millet (Burin et al, 2016), vetch (Cargnelutti Filho et al, 2017) and rye (Chaves et al, 2018), no experimental planning studies were reported for ryegrass

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Results