Biomass Yield and Forage Nutritive Value of Cynodon Grasses Harvested Monthly

Perennial grasses are the major source of livestock nutrients in subtropical and tropical regions of the world. There is a need to constantly screen for new entries with improved yield, nutitive value, and increased cool season production. Five Cynodon grasses consisting of three bermudagrasses [Cynodon dactylon (L.) Pers.,>Bermudagrass 2000 ',>Jiggs=, >Tifton 85'] and two stargrasses (C. nlemfuesis Vanderyst var. nlemfuensis,>Florona = and>Stargrass 2000') were vegetatively planted in a RCB design with six replicates, during the fall of 2000. Grasses were harvested on a 28-d schedule during both the warm (15 April- 15 October) and cool (16 October- 14 April) season over a 3 yr period to determine dry biomass (DB) yield, crude protein (CP) and in vitro organic matter digestion (IVOMD). Data was summarized separately for both the warm and cool season of each year. Total annual DB yield of Bermudagrass 2000 and Jiggs bermudagrass (27.6 Mg ha-1) was generally greater (P<0.05) than Tifton 85 bermudagrass (26.3 Mg ha-1) and both stargrasses (24.1 Mg ha-1) when averaged over 3 yr. These three bermudagrasses consistently produced greater yields during the warm season than the stargrasses. However, during the cool season greatest yields were obtained from Bermudagrass 2000, Jiggs, and Florona stargrass compared with the other grasses. These three grasses averaged 10.2, 11.1, and 10.5 Mg ha-1, respectively or 37, 40, and 41 % of their total annual yield was produced during the cool season. Average CP and IVOMD of these grasses was low (107 and 540 g kg-1 respectively) during the hot, wet summer (July- September). Nutritive value of these grasses during the cool season was good averaging 202 and 664 g kg-1 for CP and IVOMD, respectively. These data indicate Cynodon grasses can be very productive under a clipping program in central Florida when harvested on a 28-d schedule and well fertilized