Reduction of sward height in the fall and winter as a strategy to improve the structure of marandu palisadegrass (Urochloa brizantha syn. Brachiaria brizantha cv. Marandu)

Diogo O.C Sousa,Guilherme P Silva,Heron A Oliveira,Ludiêmilem K.P Costa,Manoel E.R Santos,Miriã G Simplício

doi:10.17138/tgft(5)143-152

Diogo O.C Sousa, Guilherme P Silva + Show 4 more

Open Access

https://doi.org/10.17138/tgft(5)143-152

Copy DOI

Abstract

The objective of this study was to identify defoliation strategies that might improve the structure of Urochloa brizantha (syn. Brachiaria brizantha ) cv. Marandu (marandu palisadegrass). The following 3 defoliation strategies were compared in a plot study: sward kept at 15 cm in fall and winter (W) and 30 cm in spring (Sp) and summer (Su) (15W-30Sp-30Su); sward kept at 30 cm during the entire experimental period (30W-30Sp-30Su); and sward kept at 45 cm in fall and winter and 30 cm in spring and summer (45W-30Sp-30Su). The experimental design was completely randomized, with 4 replicates. Plots were cut with shears to the appropriate height weekly in winter and twice weekly in spring, summer and fall. Tiller density, mean tiller weight, leaf area index, forage mass, percentage of live leaf blades and percentage of stems were measured every 28 days. Forage mass in winter was directly related to pasture height (P 0.05). Mean tiller density was independent of cutting height but was higher in spring and summer than in winter (P summer>winter and by cutting height in fall/winter with leaf percentage inversely related to cutting height. Stem percentage in the swards in winter was directly related to cutting height. Grazing studies seem warranted to determine if these plot results are reflected under grazing conditions and what the impacts are on animal performance.

Highlights

Pasture structure is a function of how the organs of the aerial parts of forage plants are distributed in the pasture, both vertically (Zanini et al 2012) and horizontally (Barthram et al 2005)
Tiller weight was greater in the sward maintained at 45 cm in fall/winter than in that at 15 cm, while in spring, the sward kept at 45 cm in fall/winter produced heavier tillers than that at 30 cm in fall/winter
Forage mass in the marandu palisadegrass was influenced by season of the year (P = 0.013) and by the interaction between this factor and defoliation strategy (P = 0.009)

Summary

Introduction

Pasture structure is a function of how the organs of the aerial parts of forage plants are distributed in the pasture, both vertically (Zanini et al 2012) and horizontally (Barthram et al 2005). Pasture height is highly correlated with forage mass and morphological composition (Paula et al 2012; Nantes et al 2013), in addition to being a cheap, easy and quick measurement. For this reason, average pasture height has been recommended as a management criterion for when to commence and cease grazing (Silva and Nascimento Júnior 2007). Studies on grazing management strategies, based on pasture height, enable the understanding of variations in pasture structure, as well as the responses of animals and plants to these variations (Trindade et al 2007; Fonseca et al 2012, 2013). On the basis of these findings, we conclude that grazing management strategies should be flexible over the year and vary with seasonal conditions

Objectives

Methods

Results

Discussion

Conclusion