|Tifton 85 Bermudagrass|
Tifton 85 is the best of many F1 hybrids between PI 290884 from South Africa and Tifton 68, a highly digestible but cold susceptible hybrid that was released in 1983. Tifton 85 is a sterile pentaploid. Except for Tifton 68, it is taller, has larger stems, broader leaves and a darker green color than other bermudagrass hybrids. Tifton 85 has large rhizomes (though many fewer than Coastal and Tifton 44), crowns, and very large, rapidly spreading stolons.
In two 3-year replicated small plot tests conducted beginning in 1985 and 1989, Tifton 85 produced an average of 26% more dry matter that was 11% more digestible than Coastal bermudagrass in duplicate two-acre pastures fertilized annually with 225 lb/A of N in a 4-1-2 (N-P205-K20) ratio (fertilizer split-applied in March, June and August), Tifton 85 produced an average of 47% more liveweight gain per acre per year than Tifton 78 from 1989 to 1991. Steers were added or removed from the pastures as necessary to keep all grass shorter than 4 inches. In this 3-year grazing study, steers grazing Tifton 85 continuously from mid-April to mid-October averaged 1.47 pounds per day and produced 1032 lb. of liveweight gain per acre (LWG/A) at a fertilizer cost of 5.74 per pound of gain.
Tifton 85 can make excellent hay. Tifton 85 3 1/2-week old hay fed as 15-30% of a total mixed ration was comparable to alfalfa in mixed feed fed to milk-producing Holstein cows. It should be fertilized with 75 lb/A of N in a 4-1-3 (N-P2-05-K20) blend in mid-March and after each cut. It should be cut in mid-May and every 4 to 5 weeks for top quality hay. Digestibility and overall quality of the hay decreases with each day cutting is delayed.
Dr. Jeffrey Anderson, Oklahoma State University, found that Tifton 85 bermudagrass could tolerate temperatures as low as 22oF; Coastal bermuda survived 19oF. In 1991, seventeen agronomists from Texas and Oklahoma to South Carolina established replicated small plots of Coastal, Tifton 44, Tifton 78 and Tifton 85 bermudagrasses. All grasses with dead grass cover survived minimum 1991-1992 temperatures ranging from 29o to 3oF. In all but two locations, Tifton 85 ranked first in forage production in 1992.
The stolons, that may grow more than three inches per day, develop roots and a plant at each node when soil moisture and growing conditions are favorable. In the first year, these plants remain at the surface of the soil and rarely develop crowns. An extended freeze or fire can kill them, making it necessary for the sod to establish again from the original plants. The buffering effect of the soil protects the original plants that were planted deeper. Deep planting and leaving a good cover of frosted grass will extend the northern limit for Tifton 85. The cover of dead grass can help to keep the grass dormant that is necessary to slow the "grow-freeze-back" sequences that may be repeated several times until reserves are exhausted. A good frost-killed grass cover can moderate air temperatures that reach the soil surface as much as 10 degrees F.
Tifton 85 can be established by planting sprigs or tops (green stems 18+ inches long) with mechanical planters or by broadcasting and disking them into a moist soil on cloudy, preferably misty or rainy days. Tops will die if broadcast and disked into dry, hot soil. (Tops have been cut and baled immediately with a hay bailer to facilitate handling.) For best results choose a well-drained soil with good moisture to a depth of 2 feet or more to supply water for the grass if it fails to rain for several weeks after planting. Disk 500 lb/A of a complete fertilizer such as 10-10-10 into the soil. Turn the soil with a mold-board plow, smooth with a disk harrow and plant immediately before the soil dries out. Right behind the planter, pack the soil with a heavy roller or by driving the tractor over the planting to establish the capillarity in the soil necessary to keep the soil moist around the plants. Spray immediately with 2 lb/A of 2,4-D to control germinating weed seeds. A second application will usually be required in 25 to 30 days. With weeds controlled, Tifton 85 growing in a favorable environment should cover the ground in three months.
Poor stands can rapidly produce good stands if dead grass is removed and the stubble is fertilized with 100 lb/A of N + P&K and sprayed with 2 lb/A of 2,4-D in mid-March before seeds of crabgrass germinate.
Glenn W. Burton, Roger N. Gates, and Gary M. Hill.
The Georgia Seed Development Commission, 2420 S. Milledge, Athens, GA 30605