This study hypothesized that the signal grass (Urochloa decumbens [Stapf] R. Webster) modifies its structural and productive characteristics under a silvopasture system with legume trees. The treatments were composed of (i) signal grass in monoculture and (ii) a silvopasture system intercropping signal grass + Mimosa caesalpiniifolia Benth. a legume tree, over two consecutive years. The experiment was set in a completely randomized block design with three replications. Grazing was carried out by cattle with an average body weight (BW) of 186 ± 26 kg. The type of system had no significant effect on the structural and productive characteristics of signal grass. In the first grazing season, the greatest canopy height (54 cm) and total forage mass (6473 kg DM/ha) occurred in the dry period. The leaf:stem ratio was greater in the rainy season. Forage accumulation (515 kg DM/ha/28 days) and forage accumulation rate (18 kg DM/ha/day) were greater in the rainy season. Higher total forage production (4583 kg DM/ha) occurred in the first grazing season. The silvopasture with double rows spaced 25 m apart and with a tree density of 600 plants/ha did not compromise the structural and productivity characteristics of the signal grass pasture. The legume M. caesalpiniifolia has the potential for use as an arboreal component in silvopasture systems with signal grass.

Silvopastoral systems (SPSs) are sustainable alternatives for pasture intensification. Management practices such as thinning are options to diminish competition for resources between pasture and trees, ensuring appropriate forage production. The objective of this study was to evaluate the productive and nutritive traits of Piatã palisadegrass (Urochloa brizantha cv. BRS Piatã) after thinning the forest component of a SPS. Forage production and nutritive value, along with microclimate variables were assessed in a SPS and in an intensive system (INT) in São Carlos-SP, Brazil, from 2016 to 2018. The INT was a full sun pasture of Piatã palisadegrass, while the SPS was established with Piatã palisadegrass shaded by eucalyptus (Eucalyptus urograndis clone GG100) spaced 15 × 2 m but thinned to 15 × 4 m before the onset of the experiment. In the SPS, measurements were made under the tree row (SPS_1), 3.75-m (SPS_2), 7.5-m (SPS_3) and 11.25-m (SPS_4) distant from the North row. Forage accumulation in the two systems were similar, whereas the pre-grazing forage mass in most of the SPS positions were smaller than that of the INT during the autumn of 2017 and summer of 2018. Crude protein (CP) content was greater in the SPS than in the INT in most positions and seasons. Forage production was favoured by the thinning of the trees mainly in the seasons close to the event, while forage CP was consistently greater in the understory pasture. Thinning of trees in SPSs can be adopted to provide forage production similar to intensive pastures with higher protein content.

Efforts were made to obtain forage cultivars with high production capacity and quality and to determine the ideal time to start animal grazing, respecting the morphological characteristics of the grasses. For this purpose, the nutritional value, digestibility and characteristics of the forage canopy of Aries and Aruana (Megathyrsus maximus (Jacq.) or Panicum maximum) cultivars kept under rotational stocking with sheep were evaluated and the management height was determined based on 95% light interception (LI). The experiment was evaluated with repeated measures over time (grazing cycles by season, in 2 years) with a treatment factor (grass cultivar) in a completely randomized block design with eight replicates, using 800 m2 paddocks. The height of the forage canopy before grazing (pre-grazing) determined by 95% LI stabilized around 29 cm. The highest proportion of Aruana leaf blades was observed in winter. Aries grass presented similar leaf blade percentages in summer, autumn and spring. Similar forage accumulation (FA) was observed for both cultivars, decreasing in spring, autumn and winter. Higher crude protein and in vitro dry matter digestibility (IVDMD) were seen in Aries grass, while Aruana grass presented higher neutral and acid detergent fibre and cellulose and lower IVDMD. The nutritional quality of the grasses was maintained throughout the year. The height of the forage canopy of Aries and Aruana recommended for entry into the paddock is 29 cm to maintain nutritional quality. The successful management strategy adopted for grasses combined with nitrogen fertilization provided a greater forage mass quality.