Influence of 2,4-D residues on the soil microbial community and growth of tree species.

The 2,4-D (2,4-dichlorophenoxyacetic acid) has low half-life in the soil, but it is capable of altering the soil microbial community. The objective of this study was to evaluate the influence of 2,4-D residues on the structure of the soil microbial community and the growth of tree species. The tolerance and phytoremediation potential of tree species were evaluated. The microbial analysis was performed by T-RFLP. The 2,4-D herbicide reduced the plant height of K. lathrophyton, number of leaves of C. ferrea and K. lathrophyton and root dry matter allocation for C. brasiliense, I. striata, P. heptaphyllum, and T. guianensis. Cucumis sativus intoxication on soil contaminated with 2,4-D was not significant. The structure of Fungi community in the rhizospheric soils of C. ferrea was altered. The herbicide 2,4-D increased the diversity of Fungi in rhizospheric soils of P. heptahyllum and R. grandis. Most tree species were tolerant, and the evaluation time was sufficient to remedy 2,4-D. The structures of the microbial communities Archaea, Bacteria, and Fungi were little influenced by 2,4-D. The diversity of the Archaea domain was not affected, the diversity of the Bacteria in Inga striata decreased while the fungi increased in Protium heptaphyllum and Richeria grandis with 2,4-D.