Grazing Management Effects on Productivity, Nutritive Value, and Persistence of 'Tifton 85' Bermudagrass

'Tifton 85' bermudagrass (Cynodon spp.) is an important forage in the southern United States, but its responses to the interaction of grazing frequency and intensity have not been studied. Sward persistence, herbage accumulation, and nutritive value were measured during 3 yr. Treatments were all combinations of three postgraze stubble heights (SH; 8, 16, and 24 cm) and three regrowth intervals (RI; 14, 21, and 28 d). Short SH (8 cm) with long RI (28 d) or tall SH (24 cm) with short RI (14 d) produced greatest herbage accumulation (11-15 Mg ha(-1) yr(-1)). Lowest or nearly lowest herbage accumulation occurred with 14-d RI and 8-cm SH or 28-d RI with 24-cm SH (7.4-12 Mg ha(-1) yr(-1)). Intermediate levels of RI (21 d) or SH (16 cm) produced consistent herbage accumulation regardless of level of the other factor. Nutritive value was primarily affected by RI, and P (3.1 to 2.8 g kg(-1)), crude protein (CP; 150 to 108 g kg(-1)), and in vitro digestible organic matter (IVDOM; 602 to 582 g kg(-1)) concentrations decreased as RI increased. Organic matter and nutrient mass of storage organs increased with increasing SH, but the 24-cm SH treatment exhibited greater reduction in percentage cover (similar to 43% units) than the other SH treatments (similar to 22% units) after 3 yr of grazing. These data indicate that intermediate levels of SH (16 cm) and RI (21 d) provided relatively high Tifton 85 herbage accumulation and nutritive value while minimizing negative impacts on persistence-related responses.