| In response to lacking information and producer inquiries concerning adaptation of forage bermudagrasses [Cynodon dactylon (L.) Pers.] to the Texas High Plains and increasing use of secondary water sources as irrigation, greenhouse and small plot field trials were conducted to evaluate bermudagrass as a potential component in forage-livestock systems using limited or saline irrigation. A 63-d greenhouse trial was conducted to evaluate salinity tolerance of 'Tifton 85', 'Coastal', and 'Macho' bermudagrasses. Plants were grown in sand in 2-L pots using a completely randomized design. Treatments (NaCl: CaCl2; 1:1) ranged from 1.4 to 37.5 dS m-1. Upper limit of salinity was based on a previous study. Biomass was harvested at three, 21-d intervals. Biomass reductions of 75% occurred at 27.0, 27.0, 17.0; 27.0, 19.0, 17.0; 19.0, 14.0, 14.0 dS m-1 for Tifton 85, Macho, and Coastal, respectively, at each 21-d harvest. After 63 d, Tifton 85 and Macho survived salinity up to 27.0 dS m-1, whereas Coastal survived up to 19.0 dS m-1. Productivity and nutritive value among forage bermudagrasses were tested during 2002 and 2003 in small plot trials at three locations in Texas: (1) New Deal; 12 varieties with limited irrigation (305 mm total annual) with water from the Ogallala Aquifer; (2) Posey; 5 varieties surface irrigated with industrial wastewater; and (3) Spraberry; 5 varieties surface irrigated with municipal effluent water. For locations 2 and 3, water was applied at disposal rates. Experimental design was a randomized complete block at each location. Forage mass was determined by clipped quadrates every 28 d during the growing seasons of 2 yr following establishment yr to estimate production. Mean seasonal yield of Tifton 85 was greater than other varieties (P < 0.05) with aquifer water (20.4 Mg ha-1) and industrial wastewater (17.1 Mg ha-1) but did not differ from Coastal with municipal effluent water. In vitro dry matter disappearance for Tifton 85 (63%) was higher (P < 0.05) than other varieties at each location. Growth of Tifton 85 was delayed early in spring compared with others tested. Bermudagrass appears adapted to environmental conditions of the Texas High Plains under varying irrigated conditions. |
