Submitted to: Journal of Production Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/1998
Publication Date: N/A
Interpretive Summary: Over 60,000,000 acres are used for perennial pasture in the humid south eastern U.S. In the southern portion of this region, perennial pastures are dominated by warm-season grasses, which provide a stable feed supply for livestock and maintain ground cover. However, they are unproductive during winter and feed value is often low limiting profitable livestock production. Alfalfa excels as a source of highly nutritious feed for cattle and other grazing livestock. Unfortunately, alfalfa is best adapted for hay production and has not survived more than a few years when grazed. Development of Alfagraze demonstrated that alfalfa could be selected to survive continuous grazing. Alfagraze, however, is very winter dormant, with little growth occurring from Oct through Mar, even where winters are mild. Two new non-dormant, grazing tolerant were selected and compared in 4 experiments to Alfagraze and adapted non-dormant cultivars. Both Amerigraze 702 and ABT 805 survived close continuous grazing as well as Alfagraze and much better than non-dormant check cultivars. Forage yields from late fall through early spring were higher than Alfagraze. These cultivars provide a source of very high quality livestock feed which can be harvested mechanically or by grazing. Judicious use of these alfalfas could augment the indigenous feed supply in the Southeast during critical periods when feed quality limits production.
Technical Abstract: Perennial, warm season grasses are the predominate pasture species in the coastal plain region of the southern U.S. These grasses have two major limitations: an off-season when they have limited production and poor nutritional value during most of their main growing season. Using non dormant alfalfa as supplemental grazing for grass pastures has potential to overcome these limitations because it has a long growing season in areas with mild winters and also has high nutritional quality. However alfalfa is generally not grazed due to poor stand persistence. We used selection for survival after intense grazing to develop 2 nondormant, grazing tolerant alfalfa germplasms and these were tested for survival and yield in 4 experiments of 1-2 yr duration under heavy grazing pressure with continuous stocking by beef cattle at Tifton, GA. The selected, nondormant alfalfa germplasms possessed persistence under grazing equal to the dormant cultivars, Alfagraze but better than other nondormant cultivar checks as measured by plant survival. All entries were found to possess good plant survival in control areas which were clipped at an early flowering stage. The yield distribution of nondormant cultivars showed better late autumn and early spring yields than Alfagraze, but during one winter of the four in this study, some winter damage occurred on nondormant germplasms and cultivars which was not seen with Alfagraze.