How does the sward condition in late winter influence the Marandu palisade grass (&lt;i&gt;Urochloa brizantha&lt;/i&gt; cv. Marandu) structure during spring and summer?

Manoel E.R Santos,Bruno H.R Carvalho,Gabriel O Rocha,Henrique C.R Nogueira,Gustavo S Borges,Flávia O.S Van Cleef

doi:10.17138/tgft(8)167-176

How does the sward condition in late winter influence the Marandu palisade grass (<i>Urochloa brizantha</i> cv. Marandu) structure during spring and summer?

Manoel E.R Santos, Bruno H.R Carvalho + Show 4 more

Open Access

https://doi.org/10.17138/tgft(8)167-176

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Abstract

Height and mowing of a sward in late winter can change its structure during the subsequent spring and summer seasons, which influences plant growth and animal performance. This work was conducted to evaluate the structural characteristics of Urochloa brizantha (syn. Brachiaria brizantha) cv. Marandu (marandu palisadegrass) during spring and summer in relation to the following sward conditions in late winter: short (15 cm), medium (23 cm), tall (31 cm) and tall (31 cm)/mowed to 8 cm. Stages of the grazing period (beginning, middle and end) in spring and summer were considered measures repeated over time. Leaf area index was lower in the tall pasture than in the other pastures and was lower at the beginning than at the end of the grazing period. Dead material mass was highest in the tall pasture, intermediate in the short and medium pastures and lowest in the tall/mowed pasture. Live stem mass was higher at the end than at the beginning and middle of the grazing period of the short, medium and tall/mowed pastures, contrary to that observed in the tall sward. At the end of the grazing period, tiller number did not vary among pastures. The tall pasture in late winter presents a limiting structure to animal consumption. Short and tall/mowed pastures in late winter show a favorable structure for forage plant growth and, probably, animal performance.

Highlights

Sward structure indicates the spatial arrangement of the aerial parts of forage plants in a pasture (Da Silva and Carvalho 2005) and can be characterized by its mass, bulk density and morphological composition, leaf area index and number of tillers
On deferred pastures it is recommended that the canopy be short and forage mass be reduced during the grazing period, which usually ends in late winter (Santana et al 2014)
This sward structure would allow good incidence of light at the base of the plants, which would stimulate the appearance of new tillers from early spring (Costa et al 2016; Pessoa et al 2016), favoring a more intense and rapid pasture regrowth and possibly resulting in sward structural characteristics more suitable for animal grazing during the rainy season

Summary

Introduction

Sward structure indicates the spatial arrangement of the aerial parts of forage plants in a pasture (Da Silva and Carvalho 2005) and can be characterized by its mass, bulk density and morphological composition, leaf area index and number of tillers. Researchers have been trying to develop pasture management strategies for controlling and modifying sward structure, to favor herbage production (Santos et al 2013) and high intake rate of forage by grazing animals (Mezzalira et al 2014). In this sense, on deferred pastures it is recommended that the canopy be short and forage mass be reduced during the grazing period, which usually ends in late winter (Santana et al 2014). During spring and summer, the pasture would have a lower percentage of live leaf lamina, as well as a high percentage of dead material, remaining from winter, a sward structure which is unfavorable for animal production

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