Sorption and microbial degradation of glyphosate in soil suspensions

摘要

Sorption and microbial destruction of glyphosate, the active agent of the herbicide Ground Bio, in suspensions of sod-podzol and gray forest soils has been studied. According to the adsorptive values (3560 and 8200 mg/kg, respectively) and the Freundlich constants (Kf, 15.6 and 18.7, respectively), these soils had a relatively high sorption capacity as related to the herbicide. Sorbed glyphosate is represented by extractable and bound (non-extractable) fractions. After long-term incubation of sterile suspensions, the ratio of these fractions reached 2: 1 for sod-podzol soil and 1: 1 for gray forest soil. Inoculation of a native suspension of sod-podzol soil with cells of a selected strain-degrader Ochrobactum anthropi GPK 3 resulted in a 25.4% decrease in the total glyphosate content (dissolved and extractable), whereas in a noninoculated suspension, the loss did not exceed 5.5%. The potential for the use of a selected bacterial strain in the glyphosate destruction processes in soil systems is demonstrated for the first time.