Residual effects of stylo on the morphogenetic and structural characteristics of palisadegrass pasture

Abstract

Response pattern of grasses as influenced by legume residues after its disappearance in mixed pasture is very limited in the literature. The objective of this study was to evaluate the historical effect of different proportions of Mineirão stylo (Stylosanthes guianensis (Aubl.) Sw. cv. Mineirão) on morphogenetic characteristics and structure of the Xaraés palisadegrass (Brachiaria brizantha (Hochst ex. A. Rich) Stapf cv. Xaraés) under two canopy heights over 2 years. This study used a completely randomized design with a split‐plot arrangement. The historical botanical composition (HBC24, HBC34, HBC45 and HBC52) was allocated in the plots that corresponded to the percentages of legume (24, 34, 45 and 52%) before the experimental period and pre‐grazing heights (30 and 45 cm; CH30 and CH45) in the subplots. The canopies with HBC52 showed greater leaf elongation rate (P = 0.036) and leaf appearance rate (P = 0.0041), 1.6 cm tiller−1 day−1 and 0.053 leaves tiller−1 day−1, respectively, during the growing season. There was an increase in the herbage accumulation rate with the increase of HBC (P = 0.0128). The leaf mass was higher (P = 0.0016) for the CH45 compared with the CH30 (3294 and 2450 kg dry matter [DM] ha−1, respectively). The stem mass was higher (P < 0.0001) for the CH45 compared with the CH30 (2339 and 1146 kg DM ha−1, respectively). Overall, a HBC greater than 50% stylo in the pastures allows the postponement of legume oversowing for up to 2 years. Xaraés palisadegrass should be managed at 30 cm of pre‐grazing height on intermittent stocking rate due to greater proportion of leaves.