|Springer, Tim - OKLAHOMA STATE UNIV|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 8, 1998
Publication Date: N/A
Interpretive Summary: Eastern gamagrass is a warm-season perennial grass that is highly productive and moderately high in forage quality. Grazing must be carefully managed, however, for stands of eastern gamagrass to persist. Rotational stocking has been routinely recommended as the grazing method needed for maintaining productive stands, but other management options should also be evaluated, particularly those that require fewer inputs of resources and management. A three year grazing study was conducted to evaluate the persistence of eastern gamagrass with stocking rates designed to graze eastern gamagrass to a height of 12 to 15 inches and then deferring grazing for the remainder of the season. The rationale of the approach was to increase the time period for pasture recovery as stocking rate increased. Three stocking rates were used to impose short duration of heavy stocking (3.0 steers/acre), intermediate duration of intermediate stocking (2.0 steers/acre), and long duration of light stocking (1.2 steers/acre). Seedlings emerged each spring and thickened stands over the three years. Stands under each stocking rate also maintained their productivity and vigor over the full duration of the study. Eastern gamagrass can apparently persist under a range of stocking rates if grazing is deferred for the remainder of the growing season when canopy height falls to 12 to 15 inches. This provides producers with an option to graze eastern gamagrass heavily in the early season when it is most productive and has its highest quality, and then allow pastures to recover in the late season when both productivity and quality decline.
Technical Abstract: Eastern gamagrass (Tripsacum dactyloides L.) is a warm-season perennial grass with significant forage potential. Grazing must be carefully managed for this grass to persist. A 3-yr study was conducted to evaluate the persistence of eastern gamagrass with stocking rates designed to graze eastern gamagrass to a height of 30 to 38 cm and then deferring grazing for the remainder of the season. Pastures were stocked at different rates to impose the following treatments: 1) long duration continuous stocking at a light stocking rate (LDLS; 3.0 steers ha-1), 2) intermediate duration continuous stocking at a moderate stocking rate (IDMS; 4.9 steers ha-1), and 3) short duration continuous stocking at a heavy stocking rate (SDHS; 7.4 steers ha-1). New seedlings of eastern gamagrass emerged each spring at similar densities in all three treatments. These plants survived and plant densities increased over the 3 yr for the LDLS (53%) and IDMS (59%) treatments, but not significantly for the SDHS (10%) treatment. Concentrations of nitrogen and total nonstructural carbohydrates stored in proaxes were similar in all three grazing treatments at the initiation of spring growth and late in the growing season. In the late season, ungrazed plants had higher total nonstructural carbohydrates than grazed plants, but evidently, the grazed plants did have sufficient reserves to retain their vigor. Eastern gamagrass can persist under a variety of stocking rates if grazing is deferred for the remainder of the growing season when canopy height falls to 30 to 38 cm.