Intensification of agropastoral systems on marginalized tropical soils: impacts of defoliation intensity and nitrogen fertilization

Agropastoral systems are a growing trend worldwide, however, understanding the impact of tropical pasture intensification on this system is fundamental for developing sustainable management strategies, especially in neglected soils such as Plinthosols. Therefore, this study aimed to evaluate the effect of defoliation intensity and nitrogen fertilization on the agronomic and morphological characteristics of Massai grass (Megathyrsus maximus cv. Massai grass) in an agropastoral system. The experimental design adopted was randomized blocks in a factorial scheme with split plots. The main plots consisted of two post-cutting residue heights (15 and 25 cm), and the sub-plots four N₂ of levels (0, 300, 600, and 900 kg ha⁻¹ year⁻¹ of N₂). The experimental area consisted of an agropastoral system with coconut trees (Cocos nucifera L.) and Massai grass on Concretionary Petric Plinthosol. Massai grass managed with 25 cm of residue increased the leaf area ratio by 9.83% and forage volumetric density by 11.63%, with a higher proportion of leaves and lower proportion of stem and dead material, the part with the highest nutritional value for grazing. Higher levels of N₂ also resulted in higher total forage yield. These results indicate that managing the grass leaving a residue height of 25 cm and applying 733.72 kg ha⁻¹ year⁻¹ of N₂ allows for the maximum productive potential of Massai grass in the agropastoral system on Concretionary Petric Plinthosol.