Harvest frequency effects on warm‐season perennial grass species in a subtropical region

Perennial grasses are the primary livestock feed in tropical regions; however, there is limited information regarding adaptation of important tropical grass species to the cooler subtropics. The objective of this study was to compare forage characteristics of two tropical species with those of an adapted grass in the southeastern United States. Treatments were factorial combinations of three grasses (main plots, adapted Jiggs bermudagrass [ Cynodon dactylon (L). Pers] and two tropical species, ‘Camello’ brachiariagrass ( Urochloa spp.) and Spain guineagrass [ Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs]) and two regrowth intervals (3 or 6 weeks; subplots) distributed in a split‐plot arrangement of a randomized complete block design with four replicates. Response variables during 2 years were forage accumulation and height, light interception (LI), crude protein (CP), and in vitro digestible organic matter (IVDOM) concentrations, root‐rhizome mass, and ground cover. Spain and Camello had greater forage accumulation than Jiggs from spring through summer and harvesting at 6 versus 3 weeks resulted in greater forage accumulation. Unlike reports for other species, canopy height was not strongly correlated with LI ( r = 0.45), suggesting height be used cautiously as a predictor of LI and optimum forage accumulation. Jiggs had greater CP and less IVDOM and greater root‐rhizome mass and ground cover than Camello and Spain. However, cover responses were primarily a function of species morphology, rather than a decrease in persistence due to treatment or lack of edaphic‐climatic adaptation. Spain and Camello are viable perennial forages for the subtropics and demonstrated tolerance to frequent harvests.