AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Fall 1997, No. 3
POTASSIUM: A KEY TO GOOD TURF QUALITY
Turf adds to our quality of life daily...often in ways that we don't even notice. We all enjoy the beauty of lush, green grass. Well-managed turf increases home property values and helps to boost community pride. Healthy turf reduces soil erosion and wind-blown dust. It helps to reduce noise, glare from the sun, air pollution, allergy-related pollens, and exposure to disease. Turfgrass also contributes to heat dissipation, helping to cool down those hot summer days. Proper soil fertility and fertilizer management are critical to the production and maintenance of healthy turf.
Potassium is second only to nitrogen in the amounts required by turfgrass plants. Soil potassium can be quickly depleted under turfgrass. Therefore, regular applications of potassium fertilizer are usually necessary to achieve optimum performance. In some cases, the recommended potash rate may be as much as twice that of nitrogen.
Potassium is involved in several vital physiological functions in the turfgrass plant, even though it is not a constituent of plant components such as proteins, fats and cellulose. The functions in which potassium is involved include the regulation of internal water, photosynthesis and respiration, enzyme activation, and metabolism of carbohydrates, protein and oil.
Proper potassium fertilization of turfgrass has been shown to be associated with several key benefits. These include:
The recent trend in turf areas with heavy traffic has been toward more sandy growing media to combat soil compaction. The use of sand to modify or replace existing soil may dramatically reduce the nutrient retention capacity of the turfgrass root zone. Since potassium is susceptible to leaching under these conditions, fertilization is especially important.
- Increased disease resistance. The incidence of diseases such as brown patch and dollar spot may be reduced by potassium fertilization. The increased disease susceptibility with low potassium levels is associated with thin, easily damaged cell walls and an accumulation of nitrogen and carbohydrates in the plant. This provides a favorable medium for pathogen activity.
- Increased cold and heat tolerance. The winter hardiness of warm season grasses such as bermudagrass and centipede is improved with increases in potassium levels. The heat tolerance of cool season grasses such as Kentucky bluegrass and creeping bentgrass is associated with adequate levels of potassium.
- Improved overall ability to endure stressful conditions. Satisfactory levels of potassium cause an increase in leaf turgor pressure (decrease in succulence), thicker cell walls, and increased vigor. These attributes yield turfgrass that is more likely to endure and recover from stressful conditions such as drought and excessive traffic.
Soil testing and removal rates should be used to determine turfgrass fertilization needs. Stress factors such as the degree of traffic should also be considered when designing a turfgrass fertility program.
From the golf course superintendent to the homeowner, a turf manager can enjoy healthy, resilient, and aesthetically pleasing turf by maintaining a balance among all plant-essential nutrients.
--- WMS ---
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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