How Does Controlled-Release Fertilizer Work?
There are two general ways that manufacturers use to obtain controlled-release fertilizer. The first, and oldest, method is through chemical formulation. The nitrogen is formulated as urea formaldehyde, methylene urea, IBDU or some other nitrogen compound that breaks down slowly over time. The second, and newer, method is to encapsulate inexpensive soluble nitrogen fertilizer such as urea with some material such as sulfur or plastic resin. In this case, the nitrogen is released only when the coating is damaged or deteriorates enough to allow water to get at the soluble urea inside. Does Your Spreader Affect the Controlled Release? With the chemical formulation types of controlled-release fertilizer, your spreader should have no effect on the release rate of the fertilizer. Even if your spreader breaks or chips some granules, there should be no change in overall release rate. The situation is different with encapsulated controlled-release fertilizer. If the spreader causes any physical
