Remediação de solos contaminados com sulfentrazone em função da simbiose entre Bradyrhizobium sp. E Canavalia ensiformis

Abstract

The symbiosis between phytoremediation plants and microorganisms with herbicide metabolizing enzymatic activity may be an efficient alternative for the remediation of soils contaminated with sulfentrazone. The objective of this study was to evaluate the efficiency of bioremediation of sulfentrazone contaminated soils by means of symbiosis between bacteria (Bradyrhizobium sp.) and legume (Canavalia ensiformis). The experiment was conducted between 03/2018 and 05/2018 in a greenhouse at the Federal University of Espírito Santo (UFES), testing four doses of sulfentrazone (0, 400, 800 and 1200 g ha-1 i.a.) in the presence or absence of the inoculation with Bradyrhizobium sp. BR2003 (SEMIA 6156). After 80 days of cultivation, the plants were cut, the soil was collected for chromatographic analysis and for the bioassay with millet. The concentration of sulfentrazone, at 400 and 800 g ha-1, was significantly reduced with the inoculation of the plant with Bradyrhizobium sp., averaging 30,7 and 23,3% lower than without inoculation, respectively. The symbiosis promoted reduction of up to 75% of the residual herbicide in the soil. The inoculation with symbiotic diazotrophic potentiated the soil microbiota and consequently increased the efficiency of bioremediation. Under the 1200 g ha-1 dose the decontamination was not satisfactory. The results of this work encourage the continuity of the studies on the positive interaction between symbiotic microorganisms and leguminous species aiming at the phytoremediation of the herbicide sulfentrazone.