Dynamics of benazolin under the influence of degrading maize straw in undisturbed soil columns.

The effect of organic carbon amendment on the fate of benazolin was investigated in undisturbed soil columns. The soil columns were obtained from three different soil types located in three different regions with different crop production regimes. All soils were operated in a normal crop production regime, and one of the soils was additionally operated in low and high crop production regimes. Two experimental setups were conducted, one using [(14)C]maize straw and nonlabeled benazolin and one using nonlabeled maize straw and [(14)C]benazolin. The column experiments with [(14)C]maize straw showed that the residual crop residues remained mainly in the top layer. Benazolin and its metabolites showed a higher retention in columns that were amended with maize straw compared to column without amendment. The production regimes of the soils did not influence the behavior of benazolin. The effect of maize straw incorporation on the translocation and degradation of benazolin could well be caused by a change in the soil microbial activity, leading to an enhanced degradation of benazolin and producing metabolites exhibiting a sorption behavior different from the parent.