Reed canary grass (Phalaris arundinacea L.) is a perennial fast-growing C3 plant belongs to family Poaceae with an early season growth, a wide physiological tolerance and with large possibilities of utilization. Recently, the use for bioenergy has become very perspective mainly because its high yield (5–10 t dry matter ha/year) and very good properties for combustion. The mean calorific value is about 16–18 MJ/kg dry matter. It can be usually harvested twice a year at lower cultivation inputs and shows the ability to grow in wide range of soil conditions including on land, which is not appropriate for other agricultural purposes. It has also the potential for different industrial applications, for example for biogas, ethanol, pulp and paper production, or for the production of chemical raw materials, too. The cultivation area rapidly increases, mainly in North Europe, where it is cultivated on thousands of hectares. The cultivation for energy or other industrial purposes has also benefits to the environment because of low intensity on agricultural management, supporting biodiversity and soil preservation against erosion.

Miscanthus × giganteus (M. × giganteus) is a perspective plant produced on marginal and contaminated lands with biomass used for energy or bioproducts. In the current study, M. × giganteus development was tested in the diesel-contaminated soils (ranged from 250 mg kg⁻¹ to 5000 mg kg⁻¹) and the growth dynamic, leaves quantity, plants total area, number of harvested stems and leaves, SPAD and NPQt parameters were evaluated. Results showed a remarkable M. × giganteus growth in a selected interval of diesel-contaminated soil with sufficient harvested biomass. The amendment of soil by biochar 1 (produced from wastewater sludge) and biochar 2 (produced from a mixture of wood waste and biohumus) improved the crop’s morphological and physiological parameters. Biochar 1 stimulated the increase of the stems’ biomass, while biochar 2 increased the leaves biomass. The plants growing in the uncontaminated soil decreased the content of NO₃, pH (KCl), P₂O₅ and increased the content of NH₄. Photosynthesis parameters showed that incorporating biochar 1 and biochar 2 to the diesel-contaminated soil prolonged the plants’ vegetation, which was more potent for biochar 1. M. × giganteus utilization united with biochar amendment can be recommended to remediate diesel-contaminated land in concentration range 250–5000 mg kg⁻¹.

Growing a second generation energetic plant Miscanthus x giganteus (Mxg) in former military sites appears to be a promising way to use such areas with synergic phytoremediation of contaminants (organic pollutants, potential toxic metals). Effect of Mxg growth on soil microbial communities during a two-year pot experiment with real post-military soil (Sliač, Slovakia) and the effect of potential toxic metal concentration was studied by analyses of microbial activities and phospholipid fatty acids (PLFA). Year-on-year positive changes in microbial community structure and state were detected (higher ratios of G+/G− bacteria and fungal/bacterial PLFA, and a decrease of stress indicators trans/cis and cy/pre PLFA). Portion of gram-positive bacteria correlated negatively with potential toxic metal concentrations; however, the concentration of potential toxic metals was not identified as the main stress factor—the access to bioavailable nutrients was more important. Overall, Mxg growth generally exhibited a positive effect on soil microorganisms.