Turf and Landscape - Know Your Soluble Fertilizers 4

This is the fourth in a series on soluble fertilizers for use in turf and landscapes. This post is on triple superphosphate, a phosphorus fertilizer.

Concentrated Superphosphate also known as triple superphosphate, is gray granular material containing 46% water and citric acid soluble phosphate (P2O5 ) of which the water-soluble portion is generally around 85%. This material has very good physical properties and is often used as a conditioner in complete mix fertilizers. The salt index is very low (0.21) and there is no overall effect on soil reaction. Concentrated superphosphate granules are large and are not typically used in golf green fertilizers, but may be found in lawn and fairway grade fertilizers. In most tests with fertilizer P sources, no turfgrass response differences have been observed between sources.

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

Turf and Landscape - Know Your Soluble Fertilizers 3

This is the third in a series on soluble fertilizers for use in turf and landscapes. This post is on ammonium nitrate, a nitrogen fertilizer.

Ammonium Nitrate is typically marketed in prilled form containing 33-34% N. It is highly soluble and is also marketed in solution form; generally it will be offered in combination with urea containing 28, 30 or 32% N. Prilled ammonium nitrate may be bright white in color, indicating that the prill has been coated with magnesium chloride, or beige in color, indicating that the product has been coated with a mixture of clays. Both of these coatings reduce the hygroscopicity of the product and improve handling properties. Ammonium nitrate and urea cannot be mixed together in dry form because of severely reduced handling properties. Ammonium nitrate produces only 1.8 pounds of acidity per pound of N applied upon nitrification, and thus is not as acidifying as ammonium sulfate. The salt index of ammonium nitrate, 2.99, is less than that of ammonium sulfate and thus there is less potential for turfgrass burn immediately after application. Ammonium nitrate generally does not impart as dark green a color as does ammonium sulfate and the longevity of the response is not as great.

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

Turf and Landscape - Know Your Soluble Fertilizers 1

This is the first in a series on soluble fertilizer sources for use in turf or landscapes.

Ammonium Sulfate is a white crystalline material containing 20-21% N and 24% S. If produced in the pure crystalline form it is seldom marketed. The marketed product may be grayish in color due to carbon contamination during manufacture. Nitrification of ammonium sulfate produces acidity in the soil. Upon conversion to nitrate, the ammonium ion produces 5.35 pounds of acidity per pound of N applied, thus making ammonium sulfate the most acidifying N source available. This acidifying property makes ammonium sulfate the desired N source on alkaline turfgrass soils. When applied on high pH soils, particularly those containing free calcium carbonate, ammonium sulfate should always be watered in to limit volatile loss of N. Ammonium sulfate has a high burn potential with a salt index of 3.25, therefore, it should not be applied at high rates to avoid potential turfgrass burn. Due to limited solubility ammonium sulfate is not often applied in solution form. Ammonium sulfate imparts a dark green color in turfgrasses which tends to last for at least 30 days when applied at recommended rates. Turfgrass responses to ammonium sulfate tend to last for a longer period than for the other soluble N sources, and for this reason ammonium sulfate tends to be the preferred soluble N source of many turfgrass managers.

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