Author
Gillen, Robert | |
BERG, WILLIAM - RETIRED USDA, ARS |
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/9/2004 Publication Date: 1/1/2005 Citation: Gillen, R.L., Berg, W.A. 2005. Response of perennial cool-season grasses to clipping in the Southern Plains. Agronomy Journal. 97:125-130. Interpretive Summary: Many forage-livestock systems in the Southern Plains depend on the use of winter wheat and rye to support rapid gains of young beef cattle from November through May. Replacement of these annuals with cool-season perennial grasses could potentially reduce inputs and soil erosion because the perennial grasses would not have to be re-established every year. However, the normal precipitation pattern in this region is not favorable for cool-season perennial grasses and these grasses have not been tested extensively under dryland conditions in this region. 'Barton' western wheatgrass, 'Luna' intermediate wheatgrass, 'Jose' tall wheatgrass, and 'Bozoisky-Select' Russian wildrye were harvested at heights of either 10 or 15 cm at 30, 45, or 60-day intervals. Forage production was different among species in only 1 of 3 years. Despite above-average precipitation, forage production declined for all the grasses over years averaging 2020, 1655, and 780 lb. per acre in 1998, 1999, and 2000, respectively. Autumn forage production was less than 10% of total forage production in 2 of 3 years so grazing would be limited to the spring production period. There were no consistent differences in crude protein content or digestibility among the wheatgrasses. Crude protein content was higher for Russian wildrye in April and June but higher for the wheatgrasses in May. Digestibility was lower for Russian wildrye in May compared to the wheatgrasses. Warm-season grasses invaded all plots over years. The native, sod-forming western wheatgrass was most resistant to invasion. Harvesting at a height of 10 cm or at 30-day intervals increased the invasion of weedy grasses. It is questionable whether these grasses are adapted for intensive dryland forage production on upland sites in the Southern Plains. Autumn forage production would not be more consistent than from winter wheat and total forage production would likely be less than winter wheat. Technical Abstract: Many forage-livestock systems in the Southern Plains are highly dependent on the use of winter wheat (Triticum aestivum L.) and (Secale cereale L. ) rye to support rapid gains of growing beef cattle (Bos taurus L.) from November through May. Replacement of these annuals with cool-season perennial grasses could potentially reduce inputs and soil erosion. However, but cool- season perennial grasses have not been extensively tested under dryland conditions in this region. 'Barton' western wheatgrass [Pascopyrum smithii (Rydb.) A. Löve], 'Luna' intermediate wheatgrass [Elytrigia intermedia (Host) Nevski subsp. intermedia ], '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 years. Despite above-average precipitation, production declined for all grasses over years averaging 2270, 1860, and 880 kg ha-1 in 1998, 1999, and 2000, respectively. Autumn forage production was less than 10% of total forage production in 2 of 3 years. There were no consistent differences in crude protein (CP) or in vitro digestible dry matter (IVDDM) concentrations among the wheatgrasses. CP concentration was higher for Russian wildrye in April and June but higher for the wheatgrasses in May. IVDDM was lower for Russian wildrye in May compared to the wheatgrasses. Warm-season grasses invaded all plots over years. The native, sod-forming western wheatgrass was most resistant to invasion. It is questionable whether these grasses are adapted for intensive dryland forage production on upland sites in the Southern Plains. |