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The objective of this study was to evaluate the morphogenetic and structural characteristics of Aruana guineagrass pastures (Panicum maximum cv. Aruana) subjected to rotational stocking by sheep. The treatments corresponded to grazing when swards reached 95 or 98% of interception of incident light (LI) until post-grazing heights of 10 and 15cm and were allocated to experimental units (plots of 196 m²), according to a 2 × 2 factorial arrangement in a completely randomized design, with three replications, from January to May 2009. The morphogenetic assessments included: leaf appearance and elongation rates (LAR and LER), phyllochron (PHY) and leaf life span (LLS). Structural evaluations assessed the number of green leaves (NGL), dead leaves (NDL) and expanded leaves (NEL) per tiller, tiller population density (TPD) and final leaf length (FLL). The pre-grazing sward height relatively constant during the experimental period, with values ranging between 30 and 40 cm for treatments of 95 and 98% of LI, respectively, indicating potential for the development and use of management practices based on pasture conditions goals. The morphogenetic and structural characteristics were influenced by the frequency and intensity of grazing adopted, as well as by the seasons, implying that the capacity and speed for the recovery of Aruana grass pastures after grazing depend mainly on the management and edaphoclimatic conditions. The best grazing management for Aruana guineagrass is 95% canopy light interception, i.e., 30 cm pre-grazing height pastures interrupted when reaching 15 cm residue.

The objective of this study was to assess the accumulation and morphological composition of forage in Aruana Guineagrass (Panicum maximum cv. Aruana) swards subjected to intermittent stocking with sheep. Experimental treatments when grazing was introduced included low (95%) and high (98%) incident light interception and low (10 cm)- and high (15 cm)-residue height and were allocated to experimental units (196 m² fenced areas) in a completely randomized 2 × 2 factorial arrangement with three replicates. Treatments were imposed between January and May 2009. More frequent grazing cycles (95% light interception) resulted in better control of stem elongation, lower proportion of dead plant material and invasive plants, and higher proportions of leaf blades in the grazing strata, compared with less frequent grazing cycles (98% light interception). Grass managed with 95% light interception combined with 10 and 15 cm post-grazing height and grass managed at 98% light interception combined with 15 cm post-grazing height did not show differences in forage accumulation rate. These results indicate that more frequent (30 cm pre-grazing height) and less severe (15 cm post-grazing height) grazing cycles provided animals with high leaf blade mass and low stem mass forage.