Characterization of Brachiaria decumbens cv. 'Basilisk' pasture subjected to flexible grazing by sheep

Jefte A. de A. Conrado1*, Marcos N. Lopes2, Magno J.D. Cândido1, Clemente F. dos Santos-Neto1, Leonardo F. de Morais1, Antônia F.F. Torres1, Dayanne R. do Nascimento1, and Maria S. de S. Carneiro1
The sustainability of animal production on pasture is based on improving the management of forage species used, which ensures increase in animal productivity, pasture perenniality and cost reduction. The objective was to characterize productive, structural, physiological and normalized difference vegetation index (NDVI) responses of Brachiaria decumbens Stapf 'Basilisk' over the flexibilization of the grazing management adopted. Four defoliation combinations were evaluated, which consisted of the arrangement of two (85% and 95%) light interceptions (LI) and two (1.3 and 1.8) residual leaf area indexes (RLAI), as parameters of entry and exit of the animals from the pasture, respectively. Higher total forage biomass was observed (TFB, kg DM ha-1) 18.82%, when the canopy was managed at the lowest defoliation frequencies (95% LI), but with a higher morphological composition of the stem component and dead material. The 95% LI produced an extra layer of leaves than the canopy managed at 85% LI. The physiological variables were affected by the higher frequency of defoliation (85% LI), with lower photosynthetic rates. NDVI was higher in the canopy managed in the pre-grazing condition at 95% LI (0.88) and residual condition at 1.8 RLAI (0.49), when compared to 85% LI (0.86) and 1.3 RLAI (0.44). For greater production per animal, managing at 85% LI × 1.8 RLAI with pre-grazing and residual NDVI of 0.85 and 0.49, respectively, is the most suitable while for greater animal production per area, managing at 95% LI × 1.3 RLAI with pre-grazing and residual NDVI of 0.88 and 0.44, respectively, becomes more efficient.
Keywords: Forage production, forage structure, leaf area index, NDVI, photosynthesis, rotational stocking.
1Universidade Federal do Ceará, Departamento de Zootecnia, Av. Mister Hull, 2977, Campus do Pici, CEP: 60356-000, Fortaleza, Ceará, Brasil.
*Corresponding author (jefte_arnon@hotmail.com).
2Instituto Federal do Piauí, Campus Valença do Piauí, Av. Joaquim Manoel, s/n, Centro, Valença do Piauí, CEP: 64300-00, Valença do Piauí, Piauí, Brasil.