Response of perennial cool-season grasses to clipping in the Southern Plains

Many forage-livestock systems in the Southern Plains depend on the use of winter wheat (Triticum aestivum L.) and rye (Secale cereale L.) to support rapid gains of growing beef cattle (Bos taurus L.) from November through May. Complementing these annuals with cool-season perennial grasses could reduce inputs and soil erosion, but these perennial grasses have not been extensively tested under dryland conditions in this region. We determined the production potential and response to clipping of four Triticeae grasses under dryland conditions on a Grandfield fine sandy loam (fine-loamy, mixed, superactive, thermic Typic Haplustalf). 'Barton' western wheatgrass [Pascopyrum smithii (Rydb.) A. Love], 'Luna' intermediate wheatgrass [Elytrigia intermedia (Host) Nevski subsp. intermedia 1, 'Jose' tall wheatgrass [Elytrigia elongata (Host) Nevski], and 'Bozoisky-Select' Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski] were harvested at either 10 or 15 cm at 30-, 45-, or 60-d intervals. Forage production was different among species in only 1 of 3 yr. Despite above-average winter and spring precipitation, production declined for all grasses over years, averaging 2270, 1860, and 880 kg ha(-1) in 1998, 1999, and 2000, respectively. There were no consistent differences in crude protein or in vitro digestible dry matter concentrations among the wheatgrasses. Crude protein concentration was higher for Russian wildrye in April and June but higher for the wheatgrasses in May. In vitro digestible dry matter was lower for Russian wildrye in May compared with the wheatgrasses. Warm-season grasses invaded all plots over years. Western wheatgrass was most resistant to invasion. Intermediate and tall wheatgrasses were not adapted to the conditions of this study, and any further research should focus on western wheatgrass or Russian wildrye.