The Warm Season Grasses require less Nitrogen than the Cool Season Grasses. However, their nitrogen requirement of 25 pounds is dependent on the pH level of 5.6 to 6.0 and a 30-pound per acre Phosphorus level. The phosphorus requirements vary between plant classifications. The Legumes and Cool Season Grasses require between 12.5 and 14.0 pounds of Phosphorus per ton of hay removed. The Warm Season Grasses require 5 pounds of phosphorus per acre for each ton of hay removed.
Potassium is an element that is frequently overlooked.
Legumes and the Cool Season Grasses require more potassium than the Warm Season Grasses. Red Clover requires 45 pounds of potassium and Timothy requires 56 pounds for each ton of hay removed. Smooth Bromegrass, Tall Fescue and Orchard Grass require 44 to 55 pounds for each ton of hay removed. The Warm Season Grasses requirement is much less. Potassium requirements for each ton of production is estimated at 12 pounds.