| This study is concerned with the adsorptive behaviour of two triazine herbicides on three mineral soils from Benue state, Nigeria: Aquic Ustropept, Rhodic Kanduistalf and Aeric Ochrauqualf.;The soils were characterized using physical, chemical and spectrophotometric methods. The results obtained indicate that the soils are acidic, relatively coarse and fairly low in organic matter. Infrared spectra show that the Rhodic Kanduistalf, and Aeric Ochrauqualf soils contain mainly kaolinite clay minerals while clay in the Aquic Ustropept soil is montmorillonite.;The labile sorption capacities of all three soils were found to be approximately 0.021 $mu$mol g$sp{-1}$ for metribuzin and 0.140 $mu$mol g$sp{-1}$ for atrazine.;Uptake of the herbicides was measured in terms of three processes--the immediate uptake which occurs between the time when the soil was spiked with the pesticide and the first measurement ($approx$300 s). This immediate uptake was followed by a fast process, which occurs, between 300 s and 8 hr. Finally, a third slow process occurs from 8 hr to the end of the experiment (usually about 30 days). (Abstract shortened by UMI.). |
