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This study evaluated the agronomic, morphogenic and structural characteristics of palisadegrass (Urochloa brizantha) in silvopastoral systems (SSP’s) composed of babassu palms (Attalea speciosa) and grass monoculture in the Pre-Amazon region of the state of Maranhão, Brazil. The study followed a completely randomized design, with the arrangement in split plots with six replicates for the evaluation of agronomic characteristics and 30 repetitions for the morphogenic and structural characteristics. The plots were divided into pasture environments with different palm densities (monoculture, 80, 131, 160 palms.ha-¹), and the subplots were divided into the different seasons (rainy and dry). Total forage production was affected (P < 0.05) by the interaction between palm density and season. The rainy season, compared to the dry season, presented higher total forage production, whereas among silvopastoral systems, the one with 80 palms.ha-¹ presented higher production. The same pattern was found for leaf production. In the rainy season the production of culms increased, as did the ratio leaf.culm-1. Regarding the accumulation of dead material, the only observed difference was a smaller accumulation in the dry season for pastures with 160 palms.ha-¹. In the rainy season, the leaf elongation rate, leaf appearance rate, and final leaf length had higher values in the silvopastoral system with 131 palm.ha-¹, whereas during the dry season, these variables only differed in the monoculture system. Tiller elongation rate and the phyllochron were not affected (P > 0.05) by pastoral system during the rainy season, but in the dry period, higher responses were obtained in SSPs. Overall, SSPs with 80 palms.ha-¹ favored the agronomic characteristics of pastures. Morphogenic and structural characteristics were favored by increasing palm densities. Leaf senescence and duration were not affected by the system. Objetivou-se avaliar as características agronômicas, morfogênicas e estruturais do capim-Marandu (Urochloa brizantha) em sistemas silvipastoris (SSP’s) compostos por palmeiras de babaçu (Attalea speciosa) e em monocultivo de capim-Marandu na região Pré-Amazônica Maranhense. O delineamento experimental adotado foi o inteiramente casualizado, com o arranjo em parcelas subdivididas com seis repetições para a avaliação das características agronômicas e 30 repetições para as características morfogênicas e estruturais. As parcelas foram constituídas pelos ambientes pastoris e suas densidades (monocultura, 80, 131, 160 palmeiras.ha-¹) e nas subparcelas os períodos (chuvoso e seco). A produção total de forragem foi influenciada (P < 0,05) pela interação densidades x épocas do ano. Entre as épocas, o período chuvoso foi o que apresentou maior produção total de forragem e entre os ambientes pastoris a densidade de 80 palmeiras.ha-¹ apresentou maior produção. A mesma resposta foi encontrada para a produção de folhas. No período chuvoso foi observado maior produção de colmos e relação folha. colmo-1. Para o acúmulo de material morto só houve efeito (P < 0,05) entre os períodos, onde pastagens com 160 palmeiras.ha-¹, no período seco tiveram menor acúmulo. No período chuvoso, as taxas de alongamento foliar, aparecimento foliar, e comprimento final da folha tiveram maiores valores no ambiente pastoril com 131 palmeiras.ha-¹, enquanto no período da seca, essas características diferiram (P < 0,05) somente em relação a monocultura. A taxa de alongamento do colmo e o filocrono não foram influenciados (P > 0,05) pelos ambientes pastoris no período chuvoso, no entanto no período da seca, as maiores respostas foram obtidas nos SSP’s. O sistema silvipastoril com 80 palmeiras.ha-¹ favorece as características agronômicas da pastagem. Já as características morfogênicas e estruturais são favorecidas com o aumento da densidade de palmeiras nas pastagens. As características taxa de senescência foliar e duração de vidas das folhas não são afetadas pela densidade de palmeiras nas pastagens e/ou monocultura.

The objective of this study was to evaluate the nutritive value and in situ rumen degradability of grass collected from different locations within the pasture in a silvopastoral system with different densities of trees. The silvopastoral system consisted of Urochloa (syn. Brachiaria) brizantha cv. Marandu and the babassu palm, Orbignya sp. (now: Attaleia speciosa). We used a completely randomized design with a 3 x 3 factorial arrangement for nutritional value (3 differently shaded locations and 3 palm tree densities) and a 3 x 3 x 3 factorial arrangement for dry matter (DM) disappearance (3 locations, 3 palm densities and 3 incubation times). There was no effect of location within the pasture nor of palm tree density on the concentrations of NDF, ADF, lignin, cellulose and hemicellulose. However, location influenced the concentrations of crude protein (CP) and DM, with highest CP in material grown in full sunlight. At all densities, DM disappearance at 96 h for pasture grown in full sunlight exceeded that for pasture grown in full shade. These factors need to be compounded with the possible depressant effect of trees on DM production of pasture when considering the benefits of silvopastoral systems.Keywords: Digestibility, fiber, Northeast Brazil, protein, tree-grass associations, Urochloa brizantha.DOI: 10.17138/TGFT(3)187-193