Structural characteristics and forage mass of Tifton 85 pastures managed under three post-grazing residual leaf areas

Wilton Ladeira Da Silva,Ricardo Andrade Reis,Leandro Galzerano,Ana Cláudia Ruggieri

doi:10.1590/s1516-35982013000400002

Wilton Ladeira Da Silva, Ricardo Andrade Reis + Show 2 more

Open Access

https://doi.org/10.1590/s1516-35982013000400002

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Abstract

The experiment was carried out on Cynodon spp cv. Tifton 85 pastures grazed by sheep under rotational stocking, with the objective of evaluating the structural characteristics as well as the forage mass of the pastures subjected to three grazing intensities in successive cycles. Treatments were composed of three residual leaf area indices (rLAI; 2.4; 1.6 and 0.8), allocated in completely randomized blocks with seven replications, totaling 21 experimental units. Tiller population density, pasture height, leaf area index, forage morphological composition and pasture forage mass were evaluated. The rLAI modified the tiller population density, which increased linearly with decrease in the rLAI of the pastures. Dry masses of leaf blade, stem and dead material were inferior when the rLAI imposed were lower, which resulted in differentiated forage production among the treatments. Tifton 85 pastures grazed by sheep in rotational stocking under tropical conditions with different rLAI show a modified sward structure over successive grazing cycles, mainly by alteration in the height and LAI of the plants at pre-grazing and by light interception post-grazing, which change the tiller population density. The residual leaf area index of 1.6 is the most suitable for pasture management for being equivalent to the heights of entrance and exit of animals on and from paddocks of 33 and 19 cm, respectively, which avoid great accumulation of dead material and excessive stem elongation, in addition to ensuring tillering in the sward.

Highlights

The adoption of rotational stocking can be regarded as an accurate and efficient technique aiming to minimize losses in animal raising systems on pastures, be these losses originated from pastures or grazing animals, in addition to improving productivity in these systems
Residual leaf area index affected (P
Pastures managed under rLAI of 2.4 took on average 21.3 days to reach 95% light interception (LI) and those managed under rLAI of 1.6 took 24.7 days

Summary

Introduction

The adoption of rotational stocking can be regarded as an accurate and efficient technique aiming to minimize losses in animal raising systems on pastures, be these losses originated from pastures or grazing animals, in addition to improving productivity in these systems For this grazing system to succeed, it is necessary that some prerequisites, such as the ideal moment for interruption of pasture regrowth, be well defined (Da Silva & Nascimento Júnior, 2007). The use of residual leaf area index (rLAI) has recently been studied for the interruption of grazing under rotational stocking (Cutrim Junior, 2007; Cutrim Junior et al, 2010) This rLAI related to the LI by the forage sward has promoted the understanding of forage production and aided in the management practices adopted. The remaining leaf area is the photosynthetic tissue that remains after grazing and can represent the balance between photosynthesis and plant respiration, allowing the new growth of plants to proceed (Jacques, 1994)

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