AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Summer 2000, No. 7
MAKE THE MOST OF BERMUDAGRASS PRODUCTION WITH GOOD FERTILITY MANAGEMENT
Bermudagrass is one of the most popular warm season forage grasses in the southern U.S. It has high yielding ability, drought resistance, and tolerates relatively acidic soil conditions. It can be produced for grazing, hay, or a combination of the two. Hybrid bermudagrass is generally more productive than common bermudagrass.
One of the most important factors affecting the yield, nutritive value, and stand longevity of bermudagrass is fertility. Intensive bermudagrass hay production can result in the removal and depletion of large quantities of nutrients from soils. Without proper fertility management yields will diminish, stands will thin, and profit will be lost.
Bermudagrass will take up almost 50 pounds of nitrogen per ton of hay harvested. Proper nitrogen fertilization is associated with improved shoot and root growth, stress tolerance, resiliency, and protein content. Nitrogen levels in bermudagrass tissue should be maintained at 2.2 percent of the dry matter or higher to obtain optimum yields. Common hay meadow recommendations call for the application of 100 pounds nitrogen per acre at initial green-up in the spring, followed by similar rates after each harvest except the final one. Proper balance of nitrogen with phosphorus, potassium, and other nutrients is important in maximizing nitrogen use efficiency.
As much as 100 pounds of phosphate per acre will be taken-up in the production of top bermudagrass yields. In a rapidly growing, high-yielding crop, P2O5 uptake can equal 1.2 pounds per acre per day. Sufficient phosphorus fertility is commonly associated with increased root growth and branching, increased nitrogen use efficiency, and improved drought tolerance and recovery.
Approximately 50 pounds of potash is required for every ton of bermudagrass produced. Uptake of potash can be more than 4 pounds K2O per acre per day in a rapidly growing crop. Without proper fertilization, reserves of soil potassium may be rapidly reduced under intensive bermudagrass hay production. One east Texas study showed a 69 percent reduction in soil test potassium and a 40 percent reduction in yield after three years of hybrid bermudagrass hay production without potassium fertilization. The maintenance of adequate potassium levels through the summer months up to the onset of dormancy is important in the manufacture of carbohydrates for root growth and carbohydrate storage. Potash also improves water and nitrogen use efficiency and helps maintain good stand density. In addition, adequate potassium fertility is associated with increased disease resistance and improved winter hardiness.
The secondary nutrients should not be neglected in bermudagrass production. High yields may require more than 20 pounds of magnesium and 40 pounds of sulfur per acre. Micronutrient fertilization may also be necessary in intensive, high yielding production. Liming is important in acid soil environments. Sufficient lime should be applied to maintain soil pH at 5.6 or higher.
Balanced fertility management that is based on soil tests and plant analysis and considers nutrient removal will help ensure optimum bermudagrass yield and quality, stand longevity, and maximum profit.
For more information, contact Dr. W.M. (Mike) Stewart, Great Plains Director, PPI, P.O. Box 6827, Lubbock, TX 79493. Phone: (806) 795-3252. E-mail: email@example.com.
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