From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335

Fall 2002, No. 5


Except for nitrogen, have you ever wondered which plant nutrient is required in the greatest amount by your pasture or which nutrient is removed in the greatest quantities in hay harvests? The answer is potassium.


Potassium is also essential in animal nutrition. It helps regulate the heartbeat, affects neuromuscular activity, maintains proper osmotic balance and acid-base balance in the blood system, and maintains water balance. Muscle contains most of the potassium in the bodies of animals, but it is found in every cell of the body. If cattle and lambs are fed forage and hay with optimum potassium, it can help reduce their stress when they are shipped to feedlots.

Forage will take up potassium in the following amounts (pounds of K2O per ton of forage dry matter): alfalfa=60; fescue, bromegrass, orchardgrass=50; bermudagrass, bahiagrass, dallisgrass=45; clover/grass mixtures=60. Grazing animals will return a large portion of the ingested potassium to the soil in feces and urine.

If your summer forage production seemed to drop off too rapidly as temperatures increased, if cool season forages do not respond to nitrogen rates as expected, check your soil test potassium levels. Remember, hay and silage harvests remove more potassium from the soil than any field crops. To sustain and improve production, the harvested potassium must be replaced.

Growers should consider grazing and hay demands, soil testing to evaluate their soil’s potassium-supplying power, and applying potassium fertilizer with other recommended nutrients this fall. Paying attention to potassium can improve forage and livestock production and increase farm profits.


For more information, contact Dr. Cliff S. Snyder, Midsouth Director, PPI, P.O. Drawer 2440, Conway, AR 72033-2440. Phone: (501) 336-8110. E-mail:
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