MORPHOLOGICAL COMPOSITION AND PRODUCTIVITY OF Urochloa decumbens UNDER DIFFERENT DELAY TIMES.

• DOI: https://doi.org/10.22533/at.ed.973562507018

• Palavras-chave: Tropical forage; Pasture management; Green mass; Morphological components

• Keywords: Tropical forage; Pasture management; Green mass; Morphological components

• Abstract:

  Pasture-based animal production in Brazil faces challenges related to seasonality, nutritional value, and forage elongation. Pasture deferral is a crucial management practice for optimizing forage productivity and quality. This study aimed to evaluate the morphological components and productivity of *Urochloa decumbens* under different deferral times. The experiment was conducted in Divinópolis, Minas Gerais, from April to July 2025, using a completely randomized design with four replicates. Three deferral times (30, 60, and 90 days) were applied in 9 m² plots, with initial cutting at 20 cm and nitrogen fertilization (70 kg/ha of N). The green mass (GM) and percentages of leaf blade (%LB), culm (%COL), dead material (%DM), and inflorescence (%INF) were evaluated. The results indicated that green mass productivity did not differ significantly between the 30-day (763.89 kg GM/ha) and 60-day (694.45 kg GM/ha) deferral times, but deferral for 90 days resulted in lower productivity (305.84 kg GM/ha), representing a reduction of approximately 60% and 56% compared to 30 and 60 days, respectively. This reduction was attributed to unfavorable climatic conditions (low precipitation and temperature) during the experimental period. Regarding morphological components, the highest %LAM was observed at 60 days (44.27%), while the lowest was at 90 days (26.34%). The %COL was higher at 30 days (38.05%) and lower at 90 days (10.86%). The %MM increased significantly with the prolongation of the deferral (3.88% at 30 days to 47.95% at 90 days), due to senescence and light restriction in the lower layers of the canopy. The %INF decreased only in the 90-day deferral (14.86%). It is concluded that the 30-day deferral strategy, started late, provides better accumulation of forage and leaf blades, with a lower percentage of dead material, being a viable alternative for the dry season. Prolonged deferral (90 days) significantly compromises pasture productivity and quality.