Uso de vermicomposto com diferentes tempos de maturação e micorrização na fitorremediação de cobre por Canavalia ensiformis em solo arenoso de vinhedo

Abstract

The addition of vermicompost and the mycorrhization of plants can significantly increase the efficiency of phytoremediation in sandy soils of vineyards contaminated by copper (Cu). Vermicomposting time alters chemical, physical and biological properties of the vermicompost and these can affect its efficiency as a mitigating agent in phytoremediation. The aim of this study was to evaluate the interaction between vermicompost with different maturation times and inoculation with mycorrhizal fungus in the phytoremediation of Cu by Canavalia ensiformis in a sandy vineyard soil contaminated with this metal. The soil was contaminated in the laboratory with 100 mg kg-1 of Cu. The soil was added with mineral fertilizer (MIN), cattle manure (CM), low (LMV) and high maturation (HMV) vermicompost, corresponding to 40 mg kg-1 of phosphorus (P) via vermicompost, with and without inoculation with arbuscular mycorrhizal fungus Rhizoglomus clarum. The plant C. ensiformis was cultivated in a greenhouse, and at flowering the biomass and concentrations of Cu, Zn, Mn, Ca, Mg, P and K in the soil, in the soil solution and in the plant tissue were determined, in addition to the photosynthetic pigments and oxidative stress enzyme activity. The addition of the three organic fertilizers increased the production of root and shoot dry mass of the plant. Inoculation with AMF increased the production of dry mass of roots and nodules in treatments with organic fertilizers, increasing the amount of Cu accumulated per pot and the efficiency of phytostabilization. The addition of VAM, in particular, increased the absorption of Cu by the plant in addition to mitigating the toxic effects of the metal in mycorrhizal plants. The combined use of organic fertilizers and AMF is a strategy to increase the phytostabilization of Cu by C. ensiformis in sandy soil.