Friday, March 27, 2009

Turf and Landscape - Know Your Soluble Fertilizers 2

This is the second in a series on soluble fertilizers for use in turf and landscapes. This post is on urea, a nitrogen fertilizer.

Urea is a white crystalline solid, generally marketed in prill form, containing 45-46% N. It has good physical properties and is not as hygroscopic as ammonium nitrate. It produces 1.8 pounds of acidity per pound of N and has a salt index of 1.62; thus it can be applied to turfgrass with little threat of burn when applied at recommended rates. If left on the soil surface, significant quantities of N may be lost by volatilization. Therefore, urea should always be watered in with the proper amount of water. Urea is a non-ionic compound when placed into solution and will leach rapidly through the soil profile if excess water is applied. Remember that one inch of water will effectively wet the top ten inches of a Florida sand soil profile. Urea is highly soluble and one of the materials of choice in N solution fertilizers. Generally speaking urea does not produce as good a turfgrass response as does ammonium sulfate or ammonium nitrate, but because of its ease of application in solution form, its high solubility, its low burn potential and low cost per pound of N, it is a popular soluble N source, particularly by lawn care maintenance personnel.

Reprinted from "Selected Fertilizers Used in Turfgrass Fertilization" by J.B. Sartain & J.K. Kruse, University of Florida Cooperative Extension.

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