Submitted to: Forage and Grazinglands
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 8, 2013
Publication Date: May 23, 2014
Citation: Aiken, G.E. 2014. Cool-season annual grasses interseeded into bermudagrass with improved cold-tolerance for grazing in the upper south. Forage and Grazinglands. doi:10.2134/FG-2012-0137-RS. Interpretive Summary: Bermudagrass is a warm-season perennial grass that is predominately utilized in the lower south for grazing and hay production, but new cultivars with improved cold tolerance have potential use in the upper south between the subtropical southeast and the temperate northeast. Cultivars of the grass have been developed that can tolerate colder climates. These cultivars can be utilized in the upper south for producing high yield of hay, but their growth distributions in the region are narrow compared to cultivars grown in the lower south. Furthermore, bermudagrass grown in the upper south typically does not accumulate enough growth for grazing until late May to early June. Results of a 2-yr small-plot experiment indicated that bermudagrass can be interseeded with cool-season annual grasses to provide grazing of high-quality forage in the early spring months. Interseeded cool-season grasses dampened early growth of bermudagrass, but bermudagrass growth appeared to be recovered by late summer and fall harvests. Ryegrass provided the most uniform growth over the spring harvests, which indicated this grass could be rotationally stocked with declines in forage growth before active growth of bermudagrass occurs; however, the earlier maturing wheat or rye can provide earlier grazing. This forage system has potential as an alternative to toxic endophyte-infected tall fescue, particularly for stocker production.
Technical Abstract: Bermudagrass [Cynodon dactylon (Pers.) L.] cultivars with improved cold tolerance can be utilized for grazing in the transition zone between the temperate northeast and subtropical southeast, but these bermudagrasses generally do not provide adequate growth for stocking until late May to early June. Length of the grazing season for pastures can be extended by interseeding bermudagrass with cool-season annual grasses; however, it is uncertain if competiveness of cool-season annual grasses will reduce yields and/or damage stands of the more cold tolerant bermudagrasses that are late in breaking dormancy. A small-plot experiment was conducted during two growing seasons using ‘Wrangler’ bermudagrass to compare spring and summer herbage DM yields, percentage harvested yields relative to total spring or summer herbage yields, and nutritive value among interseeded rye (Secale Cereale), ryegrass (Lolium multiflorum), wheat (Triticum sativum), rye-wheat and rye-ryegrass mixtures, and bermudagrass-only plots. Plots were harvested at 21 to 25 d intervals to mimic rotational stocking and were harvested at 2- and 4-inch stubbles to further mimic heavy and light grazing intensities. Rye and mixtures of rye with wheat or ryegrass had generally high total spring yields in both years (4140 ± 145 lb DM/acre), whereas wheat yields were low (1915 ± 188 lb DM/acre) in both years and ryegrass provided high yields in the first year (4874 ± 382 lb DM/acre) and lower yields in the second (1680 ± 362 lb DM/acre). Ryegrass and wheat were more consistent in harvested yields relative to their total spring yields, whereas the majority of the total spring yields of rye and rye mixed with wheat or ryegrass were in the first harvest (53 ± 11%). Bermudagrass-only consistently had the highest total summer yields, but any dampening of bermudagrass in interseeded plots occurred only in the 1st summer harvest. Results indicated that cool-season annual grasses can be interseeded into bermudagrass to provide grazing in spring with high-quality forage.