The heart of winter -- December through February -- is a good time to apply fertilizer to tall fescue pastures in Kansas, as long as the ground is not frozen or saturated, according to Dave Mengel, K-State Research and Extension soil fertility specialist.
Mengel said that the goal is to apply the fertilizer:
* Late enough in the year that it will not stimulate plant growth in late fall or early winter, when it won´t be utilized efficiently; and
* Early enough to make sure the nutrients have time to move down into the root zone before plant growth resumes early next spring.
The nitrogen rates currently recommended on tall fescue pasture for 2009 are lower than in the past due to historically high nitrogen prices and steady forage prices, Mengel said. The recommended rates will depend somewhat on whether the pasture will be hayed or grazed.
"At today´s prices, producers should apply about 60 to 70 pounds of nitrogen per acre to tall fescue pastures that will be hayed," he said. "If the pasture will be grazed in a conventional system, cut the nitrogen rate back to about 50 to 60 pounds per acre. That´s because conventional, full-season grazing practices typically used have low efficiency - using only about 35 percent of the forage produced. If a more efficient rotational grazing system is used, then 60 to70 pounds of nitrogen per acre would be recommended."
Nitrogen prices are volatile now though, and if they drop, Mengel recommends that growers consider upping the rates accordingly.
What source of nitrogen fertilizer is best for tall fescue pastures?
"During cool or cold weather, the source of nitrogen used on tall fescue pasture is not too important," the soil specialist said. "In general, nitrogen solutions are not quite as efficient as dry nitrogen sources when broadcast onto permanent pasture because liquid tends to get tied up, or immobilized, in the vegetation and residue on the surface a little more than dry products."
Dribbling nitrogen solutions in 15- to 20-inch bands on tall fescue pasture, is generally going to be more effective than broadcasting solutions, he added. This reduces the potential for tie-up and immobilization. However, a broadcast application is useful where producers want to add a herbicide to the liquid nitrogen for weed control.
Phosphorus and potassium fertilizer rates should be based on soil tests.
More information is available in K-State Extension publication 729, "Tall Fescue Production and Utilization," at: http://www.oznet.ksu.edu/library/crpsl2/c729.pdf and at county and district K-State Research and Extension offices.