AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Summer 1998, No. 7
Bermudagrass will take-up about 50 pounds of nitrogen per acre for each ton of hay harvested. Common recommendations call for the application of 100 lb nitrogen per acre in the spring, with the remainder applied in split applications just after, or between harvests. Proper nitrogen fertilization is associated with improved shoot and root growth, stress tolerance, resiliency, and protein higher content.
A top yielding bermudagrass crop will take-up almost 100 pounds of phosphate (P2O5) per acre. In a rapidly growing, high yielding crop phosphate uptake can equal 1.2 pounds per acre per day. If no phosphate fertilizer is applied to a soil testing high in phosphorus, bermudagrass can draw down the phosphorous soil test level by more than 10 pounds per acre. Sufficient phosphorus fertility is commonly associated with increased root growth and branching, increased nitrogen use efficiency, and improved drought tolerance and recovery.
Each ton of bermudagrass produced requires approximately 50 pounds of potash (K2O). Uptake of potash can reach over 4 pounds per acre per day in a rapidly growing crop. Reserves of soil potassium may be reduced rather rapidly under intensive bermudagrass production. 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 winterhardiness.
The secondary nutrients should not be neglected in bermudagrass production. High yields may require more that 20 pounds of magnesium and 40 pounds of sulfur per acre. Liming is important in acid soil environments. Sufficient lime should be applied to maintain soil pH at 5.5 or higher. Micronutrient fertilization may also be necessary.
Balanced fertility management and fertilization are a best management practice that help ensure optimum bermudagrass yield and forage quality, maximum stand longevity, and maximum profit.