Monday, November 13, 2006

Yield and Nutritive Value of Forage Bermudagrasses Grown in the Texas High Plains.

Mark Marsalis, New Mexico State University, New Mexico State University-ASC at Clovis, 2346 State Road 288, Clovis, NM 88101-9998

Adaptation of improved forage bermudagrasses [Cynodon dactylon (L.) Pers.] to the semi-arid regions of West Texas is uncertain.  Bermudagrass forages are potentially viable alternatives to traditional row cropping practices in limited irrigation and dryland operations.  A 2-yr study was conducted to evaluate hay productivity and forage quality of 12 varieties of bermudagrass grown with subsurface drip irrigation.  Grasses were irrigated with 312 mm of water from May 1 through August 31 in 2002 and 2003.  Seasonal total N applied was 402 kg ha-1.  Precipitation amounts during the growing season (May-Sept.) were 195 and 184 mm for 2002 and 2003, respectively.  Harvests were taken at 28-d intervals and five cuttings were obtained in both yr.  Tifton 85 yielded the highest total seasonal biomass (20.4 Mg ha-1) over both yr and the highest average biomass (4.1 Mg ha-1) per cutting numerically.  World Feeder and Macho performed poorly with respect to yield when compared with the other 10 grasses.  Although Tifton 85 exhibited high acid detergent fiber (ADF; 34.9 g 100g-1) and low total nonstructural carbohydrates (TNC; 9.3 g 100g-1), in vitro dry matter disappearance (IVDMD) was greatest (62.2 g 100g-1) when contrasted with the mean of all other varieties.  When analyzed by establishment method, total seasonal yield and mean forage mass was similar for sprigged and seeded types.  Although seeded bermudagrasses contained lower ADF and higher TNC, IVDMD was less than that of sprigged types.  These results indicate that high productivity and nutritive value of Tifton 85 is maintained in dry years in West Texas, and improved bermudagrasses can be productive and of adequate hay quality 2 yr after establishment in the harsh environmental conditions of the Texas High Plains.