A machine system and process for producing attrition resistant, controlled release fertilizer is described. In the process, a prewet solution is used to initially coat the plant nutrient to be coated followed by the separate application of the individual components used in the coating. The machine system provides an improved means for uniformly applying a single layer or multiple layers of polymer coatings to the plant nutrient.
This is a continuation of application Ser. No. 08/356,572 filed Dec. 15, 1994, now U.S. Pat. No. 5,547,486 which in turn is a continuation of application Ser. No. 08/014,519 filed Feb. 8, 1993, now U.S. Pat. No. 5,374,292.
A controlled release fertilizer material comprising a particulate plant nutrient surrounded by a coating which is the reaction product of a mixture comprising: a polyol, an isocyanate and an organic wax.
A coated triggered start product is formed from a particulate core material comprising at least one water soluble active constituent and at least one coating layer applied on the particulate core material. The coating layer causes the product to exhibit "lock-off" type release characteristics whereby release of the active constituent of the core material from the coated product is essentially completely suppressed until release is initiated by application of a trigger material to the coating layer. Processes for preparing and using such triggered start products are also provided.
