Grazing Management Targets for Tangolagrass Pastures

Nemora Guliane Mocelin,Pedro Antonio Garzón Camacho,André Fischer Sbrissia,Guilherme Doneda Zanini,Daniel Schmitt

doi:10.3390/agriculture12020279

Nemora Guliane Mocelin, Pedro Antonio Garzón Camacho + Show 3 more

Open Access

https://doi.org/10.3390/agriculture12020279

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Abstract

Tangolagrass (Brachiaria arrecta × Brachiaria mutica) is a stoloniferous warm-season grass considered as an alternative to forming permanent grasslands in waterlogged tropical regions. However, information about grazing management targets for such species is still scarce. This two-year study aimed to identify pre-grazing canopy heights that do not compromise both leaf lamina production and nutritive value of tangolagrass pastures, and to test whether lower canopy height could decrease stolon elongation process. To this end, three pre-grazing canopy heights (20, 30, or 40 cm, all lowered in 40% of their initial heights) were assigned to nine 390-m2 plots grazed by cattle. Herbage, leaf, and stem accumulation rates were not different among treatments (57, 23, and 27 kg DM ha−1 d−1, respectively; p > 0.05). Also, neutral detergent fiber (NDF) and acid detergent fiber (ADF) were similar among treatments (56 and 24% DM, respectively; p > 0.05), but crude protein (CP) was greater (p = 0.0180) in pastures managed with 30 cm (24.7% DM × 22.5% DM). Thus, pre-grazing canopy heights between 20–40 cm combined with low levels of defoliation (up to 40% of the initial height) provide the same primary productivity in tangolagrass pastures. However, stolon elongation could not be reduced within such canopy height targets.

Highlights

Tangolagrass is a perennial warm-season grass originated from a natural hybridization between tannergrass (Brachiaria arrecta [Dur & Schinz] Stent) and angolagrass
This amplitude is due to “homeostatic” mechanisms that operate at the community level, whereby compensatory changes in tiller population density (TPD) and tissue flow buffer net herbage production [3,5,6]
Stem/stolon elongation in tangolagrass pastures seems to have a strong genetic programming that is only slightly modulated by managements based on canopy heights

Summary

Introduction

Tangolagrass is a perennial warm-season grass originated from a natural hybridization between tannergrass (Brachiaria arrecta [Dur & Schinz] Stent) and angolagrass (Brachiaria mutica [Forssk.] Stapf.), that presents stoloniferous growth habit, spreads vigorously, forms a strong root system from nodes, and is well-adapted to poorly drained soils. Like other brachiariagrasses, it has a greater herbage production capacity, tolerates marginal soil fertility conditions, and is resistant to trampling. Grasslands can be managed within a range of canopy-based targets (herbage mass, leaf area index [LAI], or grazing height) without compromising net herbage production [3,4,5,6,7]. Delaying grazing when the canopy reaches the critical LAI [8] in pastures under intermittent stocking, or by using taller grazing heights in pastures under continuous stocking, may increase leaf senescence and stem elongation rates [6,9,10,11]; decreasing net herbage production, nutritive value, and animal performance [12]

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