Controlled release of the herbicides 2,4-D and dichlobenil from alginate gels


  • William J. Connick Jr.

    1. Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, Louisiana 70179
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The herbicides 2,4-D[(2,4-dichlorophenoxy)acetic acid] and dichlobenil (2,6-dichlorobenzonitrile) were individually incorporated into 1.6–2.8-mm alginate gel beads by using calcium chloride and barium chloride as gellants. The release rate of each herbicide from the beads into water was greatly influenced by drying and the choice of gellant cation. Slowest release was obtained with dried samples that were gelled with barium chloride. At the slowest rates, release of 2,4-D was complete in 14 days, while only 59% of the less-soluble dichlobenil was released in 150 days.