Long-Term Controlled Release of Herbicides

Research on controlled-release of pesticides has resulted in products designed to extend bioactivity for periods of several days, months, or at most, several years. However, recent research directed toward solving problems associated with plant-root penetration through caps and liners that are designed to minimize leaching or movement of buried nuclear and chemical wastes has resulted in development of a long-term controlled-release herbicide delivery system designed to stop root growth for periods of up to 100 years. Through the unique combination of polymers with a herbicidally active dinitroaniline, a cylinderical pellet (9 mm long and 9 mm in diameter) was developed that continuously releases a herbicide for a period of up to 100 years. Equilibrium concentration of the herbicide in soil adjacent to the pellet and the bioactive lifetime of the device can be adjusted by changing the size of the pellet; the type of polymer; the type, quality, and quantity