PRELIMINARY ASSESSMENT OF THE USE OF BIOLOGICAL AGENTS TO ENHANCE SORGHUM BICOLOR BIOMASS PRODUCTION AND PHYTOREMEDIATION CAPACITY: GREENHOUSE AND FIELD EXPERIENCES

The cultivation of lignocellulosic crops on lands contaminated by heavy metals can represent a double solution for the production of biomass avoiding ILUC effect and providing for the decontamination of the lands through phytoremediation processes. Biomass sorghum is one of the most promising crops for this dual purpose. In the present study field and greenhouse trials have been performed to evaluate the best biological agents to increase biomass productivity and consequently heavy metals uptake in a soil contaminated by Zn, Cu, Pb, Ni and Sn. In the greenhouse trial the following biostimulant treatments have been evaluated: mycorrhiza (M), foliar biostimulants (F), root biostimulants (R), combinations of MF and MR, and the untreated control (C). After 14 weeks MR and MF were found capable of improving the productivity of plants in fresh and dry weight and the total amount of Zn and Cu extracted, while no difference was found for the concentrations of metals in the biomass. These two treatments were then tested under field conditions (a former landfill) together with the untreated control. At the end of the first year of growth, their ability to improve sorghum productivity was confirmed, while only MR was able to determine an increase in the total Zn uptake.