Spring grazing reduces seed yield of cool-season perennial grasses grown in the southern Great Plains

Information is lacking regarding management of cool-season perennial grasses for seed production in the southern Great Plains. Our objective was to determine the effect of spring grazing on seed yield of cool-season perennial grasses grown in the southern Great Plains. Treatments consisting of no spring grazing by beef cattle (Bos spp.), limited spring grazing, and extended spring grazing were applied to 'Paiute' orchardgrass (Dactylis glomerata L.), 'Lincoln' smooth bromegrass (Bromus inermis Leyss), and 'Manska' pubescent wheatgrass (Thinopyrum intermedium subsp. barbulatum (Shur) Barkw. & D.R. Dewey) in 1998 to 2000, and to pubescent wheatgrass alone in 2001. Date of first hollow stem, when elevation of apical meristems became evident, was also determined. Limited vs. no spring grazing led to decreased seed yield in 7 of 10 Species X Year combinations, whereas extended vs. limited spring grazing led to declines in seed yield in six of nine Species X Year combinations. Date of first hollow stem occurred from late March to early April for orchardgrass and smooth bromegrass, and early to mid-April for pubescent wheatgrass. Seed yield of orchardgrass and pubescent wheatgrass decreased as grazing time after first hollow stem increased. Commercial seed production of smooth bromegrass, which averaged 336 kg ha^-1 with no spring grazing, may be feasible in the Southern Plains. However, spring grazing does not appear to be a viable component of seed production systems for cool-season perennial grasses in the Southern Plains based on the likelihood of decreased seed yield associated with spring grazing.