ABSTRACT
Two procedures were employed to study the effects of various adjuvants on the leaching of selected herbicides in soil: (1) percolation through soil columns and (2) soil thin-layer chromatography (TLC). The relative leachabilities of dicamba (highly mobile), atrazine (intermediate), and chlorpropham or trifluralin (relatively immobile) were confirmed in both systems. Certain surfactants, at high rates, markedly enhanced herbicide mobility. Even chlorpropham and trifluralin were leachable under appropriate conditions. However, the anionic, nonionic, and cationic surfactants tested caused variable effects on water movement and herbicide movement, depending on the herbicide, surfactant, dosage or concentration, soil type, and preleaching conditions. Generally, the herbicides were less mobile in a Dismal Swamp organic soil (80% organic matter) than in Norfolk sandy loam.
