Tillering of Marandu palisadegrass maintained at fixed or variable heights throughout the year

Bruno H.R Carvalho,Denis D Pessoa,Guilherme P Silva,Manoel E.R Santos,Natascha A.M Silva,Róger C Cardoso

doi:10.17138/tgft(4)101-111

Bruno H.R Carvalho, Denis D Pessoa + Show 4 more

Open Access

https://doi.org/10.17138/tgft(4)101-111

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Abstract

Satisfactory tillering is the basic attribute to ensure stability and productivity of a grass population. We aimed to develop an understanding of tillering in Urochloa brizantha syn. Brachiaria brizantha cv. Marandu (Marandu palisadegrass) maintained at constant or variable heights during the various seasons of the year and to identify defoliation strategies that optimize tillering. In an experiment conducted in Uberl â ndia, Minas Gerais, Brazil, 3 defoliation strategies were studied: sward kept at 30 cm during the whole year (constant height); kept at 15 cm in fall/winter, 30 cm in spring and 45 cm in summer (increasing height); and kept at 45 cm in fall/winter, 30 cm in spring and 15 cm in the summer (decreasing height). The experiment was completely randomized, with 4 replicates. The following variables were evaluated: tiller appearance (TAR), mortality (TMR) and survival (TSR) rates; the balance (BAL) between TAR and TMR; tiller population stability (TPS); and number of tillers/m 2 (NT). In winter and late spring, TAR and BAL were low, while in early spring, the sward with decreasing height showed high TAR, BAL and TPS. The NT was higher when managed with increasing height than with other height strategies. Lowering pasture height from 45 to 30 cm after the winter increased TAR in early spring. Grazing studies seem warranted to assess how these results can be reproduced under grazing and how pasture yield and quality plus animal performance compare with those under the fixed grazing height regimen. Keywords: Defoliation, grazing management, pasture height, tillers, Urochloa brizantha. DOI: 10.17138/TGFT(4)101-111 Normal 0 false false false PT-BR X-NONE X-NONE

Highlights

In Brazil, it is estimated that 85% of pastures belong to the genus Urochloa syn
This study aimed to develop an understanding of the tillering patterns in Marandu palisadegrass kept at constant or variable heights during the various seasons of the year and identify defoliation strategies to optimize tillering, and stability and productivity of the plant population in the pasture
In winter and late spring, no difference was detected in tiller mortality (TMR) between defoliation strategies, but in summer, the sward with decreasing height showed a higher TMR and in early spring the sward with constant height had lower TMR (Figure 4)

Summary

Introduction

In Brazil, it is estimated that 85% of pastures belong to the genus Urochloa syn. Brachiaria (Macedo 2004), and that, of the 190 Mha, 50 Mha are monocultures of U. brizantha cv. Marandu (Jank et al 2014). Despite the widespread adoption of these pastures, adoption of adequate management practices is low, resulting in low livestock production (Ferreira et al 2013). For Marandu palisadegrass to express its forage production potential, proper defoliation management should be adopted. Defoliation influences light interception and photosynthesis in the sward (Lara and Pedreira 2011), key processes in the development of the forage plant, and in pasture production

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