The effects of plant biostimulant and mycorrhiza applications on industrial hemp (Cannabis sativa L.) growth and phytoremediation performance

Industrial hemp (Cannabis sativa L.) is a fast-growing lignocellulosic crop suitable for the phytoremediation of heavy metals, radionuclides, and organic contaminants on polluted marginal lands. The objective of this study was to evaluate the effects of plant biostimulant and mycorrhiza applications on the phytoremediation performance and growth of industrial hemp under greenhouse conditions. A 4-month pot experiment was performed in a Completely Randomized Design with six treatments (replicated three times): control (untreated), biostimulants B1 and B2 i.e., protein hydrolysates and fulvic/humic acids, respectively, mycorrhiza (M), and two biostimulant-mycorrhiza combinations, namely B1 × M, and B2 × M. Treatments affected plant height and number of leaves. Mycorrhiza application resulted in 30 and 37% higher fresh and dry aboveground biomass, respectively, compared to control plants. This treatment increased Cd accumulation; B1 and B2 × M increased Ni uptake (≥50%) when compared to the untreated plants. Significant were the effects of treatments on the accumulation of Pb, Zn, and Sb on plant shoots. Further research is required to evaluate more combinations of biostimulants, mycorrhiza and other natural environmentally friendly tools to optimize the use of industrial hemp and other multipurpose lignocellulosic crops for phytoremediation purposes.