Optimal plot size for experiments with black oats and the common vetch

Abstract

The aim of this study was to determine the optimal plot size for evaluating the fresh weight of black oats (Avena strigosa Schreb) and the common vetch (Vicia sativa L.) in scenarios comprising combinations of the number of treatments, number of replications and levels of precision. Fifteen uniformity trials were conducted with single-crop and intercropped black oats and vetch. Fresh weight was evaluated in 540 basic experimental units (BEU), each of 1 m × 1 m (36 BEU per trial). The Smith index of soil heterogeneity (1938) was estimated. Plot size was determined using the HATHEWAY method (1961), in scenarios comprising combinations of i treatments (i = 5, 10, 15 and 20), r replications (r = 3, 4, 5, 6, 7 and 8) and d levels of precision (d = 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18% and 20%). To evaluate the fresh weight of monocropped or intercropped black oats and vetch in a completely randomized or randomized complete block design, with from 5 to 20 treatments and five replications, plots of 10 m2 are sufficient to identify, at a probability of 0.05, significant differences between treatments of 10% of the overall mean value of the experiment.

Experimental dimensions and precision in trials with millet and slender leaf rattlebox

“…There were marked reductions in variance per BEU [VU (X) ] with plots of up to four BEU in size (4 m²), intermediate reductions with plots between four and ten BEU, and stabilization trend with plots larger than ten BEU (Figure 1). In species with potential for soil cover, such as: turnip (CARGNELUTTI FILHO et al, 2014a); velvet bean (CARGNELUTTI FILHO et al, 2014b); flax (CARGNELUTTI FILHO et al, 2018); and black oats with common vetch (CARGNELUTTI FILHO et al, 2020), the pattern was similar. Therefore, to evaluate the fresh matter of millet and slender leaf rattlebox, in single cropping or intercropping, a plot of up to ten BEU (10 m 2 ) is suggested because the gain in experimental precision (decrease in VU (X) ) with progressive increases in plot size, from ten BEU, was not significant.…”

“…The application of the methodologies of Smith (1938) and Hatheway (1961) in a set of uniformity trials conducted with millet and slender leaf rattlebox, in single cropping or intercropping, makes it possible to calculate the optimal plot size according to the experimental design, number of treatments, number of replicates and experimental precision. These methodologies have been used in common bean (MAYOR-DURÁN; BLAIR; MUÑOZ, 2012), in sunflower (SOUSA et al, 2015; SOUSA; SILVA ; A S SIS, 2016), banana (DONATO et al, 2018), cactus pear (GUIMARÃES et al, 2019(GUIMARÃES et al, , 2020 and in species with potential for soil cover, such as: turnip (CARGNELUTTI FILHO et al, 2014a); velvet bean (CARGNELUTTI FILHO et al, 2014b); flax (CARGNELUTTI FILHO et al, 2018) and black oats with common vetch (CARGNELUTTI FILHO et al, 2020).…”

Methods for Estimating the Optimal Plot Size for Black Oat, Common Vetch and Forage Turnip Intercropping

“…This size of 15.13 m 2 is relatively larger than those established to evaluate the fresh matter of sole crops of black oat (CARGNELUTTI FILHO et al, 2014a), common vetch (CARGNELUTTI FILHO et al, 2017 and forage turnip (CARGNELUTTI FILHO et al, 2011, 2016 and the intercropping of black oat and common vetch (CARGNELUTTI FILHO et al, 2020), which was equal to 4.14, 4.52, 1.20, and 10 m², respectively. Additionally, this size of 15.13 m 2 is relatively smaller than those used in experiments with the O+V+T intercropping, together with other soil cover species, by Rigon et al (2011), Ziech et al (2015, Wolschick et al (2016), Michelon et al (2019) andHaskel et al (2020), which ranged from 18 to 48 m².…”

“…Plot size has been investigated in sole cropping of black oat (CARGNELUTTI FILHO et al, 2014a), common vetch (CARGNELUTTI FILHO et al, 2017) and forage turnip (CARGNELUTTI FILHO et al, 2011, 2016, through the method of maximum curvature of the coefficient of variation model (PARANAÍBA; FERREIRA; MORAIS, 2009a) and also in forage turnip (CARGNELUTTI FILHO et al, 2014b) and black oat with common vetch (CARGNELUTTI FILHO et al, 2020) through the methodologies of Smith (1938) and Hatheway (1961).…”

Edaphic fauna and soil properties under different managements in areas impacted by natural disaster in a mountainous region

“…However, their biomass contains a higher C:N ratio compared to that of legumes (Snapp et al, 2005;Chu et al, 2017). On the other hand, legumes like common vetch (Vicia sativa) are an alternative source of nitrogen, commonly used as a cover crop in winter (Aita et al, 2001;Cargnelutti Filho et al, 2020). Intercropping of black oats with vetch results in a high residue production and hinders spontaneous plants growth (Forte et al, 2018).…”