Due to the great production of siderurgical residues, its use has been indicated in agriculture as an alternative source of micronutrients to the plants. The aim of this study was to evaluate the effect of aciary oven powder application on soil microbiota and its potential use as micronutrient source for soybean growth. An experiment was conducted under greenhouse conditions in a completely randomized block design, with Typic Haplorthox (LVA) and Clay Rhodic Hapludox (LV), four levels of siderurgical residue (0; 0.75; 1.50 and 3.00 g pot-1, corresponding to 0, 1, 2 and 4 ton ha-1), and four replicates. The soils were limed and fertilized before addiction of the residue and sowing of inoculated soybean, in plastic pots of 1.5 L (two plants per pot). During the blooming of plants, soil samples of all treatments were collected for determination of shoot and root dry matter, shoot concentrations of B, Cu, Fe, Mn, Zn, Cd and Pb, number and dry matter of nodules, nitrogenase activity, semi-quantitative evaluation of associative diazotrophics, microbial activity (basal and induced respiration), microbial biomass C, and qCO2. The microbial communities of both soils vary with the siderurgical residue, demonstrating larger sensibility to the effect of the residue than the soybean growth and nodulation parameters. The residue has a potential to be used as source of Zn to the soybean culture, at doses 0.5 ton ha-1 for LVA and 1.4 ton ha-1 for LV.
siderurgical residue; biomass; trace elements; diazotrophy
