Morphogenesis in guinea grass pastures under rotational grazing strategies

Denise Baptaglin Montagner,Domicio do Nascimento Júnior,Valéria Pacheco Batista Euclides,Marciele Neves Carloto,Sila Carneiro da Silva,Braulio Maia de Lana Sousa,Hélio Henrique Vilela,Márcia Cristina Teixeira da Silveira

doi:10.1590/s1516-35982012000400008

Denise Baptaglin Montagner, Domicio do Nascimento Júnior + Show 6 more

Open Access

https://doi.org/10.1590/s1516-35982012000400008

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Abstract

This study was conducted in order to evaluate the morphogenetic and structural characteristics of guinea grass cv. Mombasa under three post-grazing heights (intense - 30 cm, lenient - 50 cm and variable - 50 in spring-summer and 30 cm in autumn-winter) when sward light interception reached 95% during regrowth. Post-grazing heights were allocated to experimental units (0.25 ha) in a completely randomized block design with three replications. Post-grazing heights affected only leaf elongation rate and the number of live leaves. Pastures managed with variable post-grazing height showed higher leaf elongation rate in the summer of 2007. This management strategy also resulted in a higher number of live leaves. During the spring of 2006, plants showed lower leaf elongation rate, leaf appearance rate and number of live leaves, and greater phyllochron and leaf lifespan. In contrast, during the summer of 2007, the leaf appearance rate, leaf elongation rate, number of live leaves, and final leaf length were greater while phyllochron, stem elongation rate, and leaf senescence rate were lower. The management of the guinea grass cv. Mombasa with intense or variable post-grazing height throughout the year seems to represent an interesting management target, in terms of leaf appearance rate and number of live leaves.

Highlights

The use of morphogenesis to study growth and development of plants in sward allows for a better understanding of dynamics responses of the sward to defoliation (Silveira et al, 2010; Sousa et al, 2010, 2011)
The experiment was carried from September 2005 to April 2007, in guinea grass
Intermediate leaf elongation rate was observed in the other seasons

Summary

Introduction

The use of morphogenesis to study growth and development of plants in sward allows for a better understanding of dynamics responses of the sward to defoliation (Silveira et al, 2010; Sousa et al, 2010, 2011). The intraspecific competition for light increases progressively; the stem elongation, the leaf senescence rate, and the death of the tillers intensify while the leaf accumulation decreases (Carnevalli et al, 2006; Barbosa et al, 2007). These morphophisiological changes occur after 95% interception of light by the sward, a fact that has been characterizing this point with the ideal moment to interrupt the regrowth (Da Silva & Nascimento Júnior, 2007; Da Silva et al, 2009). Variation in grazing intensity throughout the year may be an alternative approach to increase pasture utilization during the spring and the summer and to control stem accumulation during autumn and winter

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