LOVELAND, Colo. (August 19, 2009) - Agrium Advanced Technologies, a leading manufacturer of slow- and controlled-release fertilizers and micronutrient products, has added three coated potassium sulfate (SOP) products and one coated potassium magnesium sulfate (K-Mag) product to its line of POLYON® controlled-release fertilizers. The new POLYON fertilizers feed the plant's root zone slowly and consistently with the potassium needed in order to thrive, helping nursery and greenhouse growers cultivate green, healthy plants.

Most fertilizers release potassium too quickly for plants to use it all, particularly in potted mediums where soils percolate high amounts of water. POLYON controlled-release fertilizers have a coating that allows gradual, consistent release of potassium, so one application can last the entire crop cycle.

POLYON controlled-release fertilizers encapsulate nutrients within a patented polyurethane membrane that meters out nutrients for months at a time and is not affected by excess moisture. With its advanced polymer coating technology, POLYON coated SOP and coated K-Mag fertilizers maximize nutrient use and minimize nutrient loss.

Agrium Advanced Technologies has introduced three POLYON coated SOP fertilizers in longevities lasting from three to 12 months. The 0-0-45 product offers the longest longevity (10 to 12 months), the 0-0-46 product lasts five to six months, and the 0-0-47 product lasts three to four months.

For horticulture, where chloride sensitivity can be a concern, POLYON coated SOP fertilizers are better options than other potassium sources. SOP has the lowest salt index at 0.84, and therefore the lowest burn potential, compared to muriate of potash (MOP) at 2.29 and potassium nitrate at 4.25.

"Potassium is one of the most leachable macronutrients and is second only to nitrogen in plant usage," said John Johnson, director of innovation, Agrium Advanced Technologies. "Other potassium sources quickly flush through the potted soils used in greenhouse and nursery operations, but the unique POLYON coating technology gradually delivers potassium so the plant can better utilize this major nutrient and minimizes environmental losses."

Agrium Advanced Technologies now offers a three- to four-month POLYON coated K-Mag, with a 0-0-20-9Mg analysis, to complement the existing eight- to nine-month product. These products deliver the added benefit of magnesium, a secondary macronutrient that is essential to chlorophyll production and is often times deficient in horticulture operations.

"In greenhouses, soils become increasingly deficient in magnesium because a lot of nitrogen and potassium are added to push growth," said Johnson. "POLYON coated K-Mag supplements magnesium while providing the controlled-release potassium plants need."

These and other POLYON products are available from Harrell's and Apex distributors.