Use Of Plant Growth-Promoting Bacteria And Humic Acids For Phytostabilization of Acid-Generating Mining Wastes

Abstract

Generation of acidic mine drainage is a major environmental problem in areas with mining waste. The cost-effective method for reclaiming of acid-generating mining wastes is a vegetation cover. Using plant growth-promoting bacteria (PGPR) and humic acid in remediation have several beneficial effects. The application of both humic substances and PGPR resulted in a decrease in Cu, Fe, Zn and sulfate concentrations in a variety of drainage water samples. Both PGPR and humic acid improve plant growth when used separately, however, the combination of both treatments has the most positive effect on fresh biomass yield – between 22% and 43 % and dry biomass of plants – between 31% and 41 %. Furthermore, addition of Bacillus and Pseudomonas bacteria, in combination with humic acids, to poor soil for reclamation improved grass mineral nutrition and reduced Cu and Zn uptake. The treatment with PGPR and humic acids significantly increased the uptake of nitrogen, phosphorus and potassium by plants.

1 Effects of Phosphate-rock Mining Wastewater Fertigation on Chickpea (Cicer arietinum) Cultivation and Soil Microbial Diversity

“…In contemporary investigations, the synergistic interaction between Plant Growth-Promoting Rhizobacteria (PGPR) and mining waste has been the subject of scientific inquiry. Bratkova et al (2021), reported that employing a combination of PGPR with humic acids in nutrient-depleted soil for the reclamation of acid-generated mining waste proves beneficial in enhancing the mineral nutrition of the grass while simultaneously reducing the absorption of Cu and Zn, and each treatment individually enhanced plant growth. Furthermore, it was reported that, PGPR enhances both root length and adaptability in soils contaminated by mining activities (Daraz et al 2023).…”

Biostimulant activity of humic acids derived from goat manure vermicompost and lignite in relation to their structure and interaction with a PGPR strain under semiarid conditions

“…Variable results have been observed in the joint application of humic acids and plant growth promoting rhizobacteria (PGPR). Eventually, this combination could have not the best effect on plant performance compared to the separate application of each biostimulant (Ahmad et al, 2016;Valero et al, 2016;Bacilio et al, 2017;Bratkova et al, 2021). Some authors have hypothesized that these results are generated by modulating effects of a "hormonal balance" in microorganism-plant communication (Blouin, 2018).…”