Evaluation of marandu palisadegrass regrowth intervals in silvopastoral and monoculture systems

Silvopastoral systems (SPS) offer a sustainable alternative for animal production in tropical ecosystems. This study aimed to evaluate the effects of deferment days on herbage accumulation, plant-part composition, and canopy structural characteristics of Marandu palisadegrass (Urochloa brizantha Hochst. ex A. Rich.) in SPS with Eucalyptus urophylla and monoculture (MC). The experiment was conducted using a randomized block design, with each system individually allocated at the center of each plot in a 3 x 4 factorial arrangement, consisting of three systems: monoculture, and silvopastoral systems with tree row spacings of 12 m and 18 m, and tree intra-row spacing of 2 m, across four regrowth periods (60, 90, 120, and 150 days), each with three replications. Increasing deferment days reduced the proportion of green components in the forage, affecting tiller population density (TPD), leaf dry mass (LDM), and leaf/stem ratio. Maximum LDM production occurred at approximately 88 days with 0.63 Mg ha-1, while peak green dry mass (GDM) was at 94 days, reaching 1.11 Mg ha-1. Both dead material dry mass (DMDM) and total dry mass (TDM) increased linearly with regrowth periods, although TDM comprised about 47% dead forage. A regrowth period of 94 days from March is feasible for Marandu palisadegrass in SPS with 12 m and 18 m between tree rows, demonstrating that this spacing does not hinder forage production.