Tillering dynamics in pastures of guinea grass subjected to grazing severities under intermittent stocking

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

doi:10.1590/s1516-35982012000300010

Denise Baptaglin Montagner, Braulio Maia de Lana Sousa + Show 5 more

Open Access

https://doi.org/10.1590/s1516-35982012000300010

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Abstract

This experiment was carried out to analyze the tillering dynamics of the species Panicum maximum cv. Mombaca subjected to three post-grazing heights: residue of 30 cm (30); residue of 50 cm (50); and residue of 50 cm during spring and summer, lowered to 40 cm in the first fall season grazing and to 30 cm in the following grazing cycle, resuming to 50 cm after the first grazing of the following spring season (50-30). Grazings were initiated whenever the swards intercepted 95% of the incident light. The post-grazing heights were allocated in the experimental units in a completely randomized block design with three replications. The density of basal tillers did not vary between the residual heights evaluated. Swards managed with variable residual height (50-30) presented higher rates of appearance and mortality of basal tillers during the summer of 2007, indicating high tiller renovation. Regardless of the post-grazing height evaluated, lower rates of appearance of basal tillers were found in the spring of 2006. The stability index of guinea grass cv. Mombaca was close to 1.0 throughout the experimental period. Swards managed with variable post-grazing present structural changes able to improve the regrowth vigor, which may be important to maximize the use of the forage species in the production system.

Highlights

The tiller is the basic unit used in the production of forage grasses, which utilize tillering as a means of growth and mainly of survival (Hodgson, 1990)
Species persistence in pasture is associated with the maintenance of plant populations and their production over time (Matthew et al, 2000), which is linked to a dynamic and harmonious balance between mortality and appearance of tillers, in a way that all dead tillers are replaced by new tillers (Da Silva et al, 2008)
Pastures grazed at 30 cm had an average of 374 tillers/m2, while pastures maintained at 50 cm and 50-30 cm, had 356 and 386 tillers/m2, respectively

Summary

Introduction

The tiller is the basic unit used in the production of forage grasses, which utilize tillering as a means of growth and mainly of survival (Hodgson, 1990). The quantity and quality of light incidence, varying between the year seasons, may act on the activation of buds and, on the production of new tillers (Deregibus et al, 1983; Casal et al, 1985), promoting differences in tiller density in different seasons (Difante et al, 2008; Sbrissia et al, 2010). The intensity of the grazing applied to pastures alters the quantity and quality of light incidence reaching the interior of the Studies on tiller density seem to be a good tool to predict these variations and, to determine a managing strategy for the grazing system to maintain an adequate density aimed at optimizing forage production throughout the year (Lemaire & Chapman, 1996).

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