Influence of the bentonite-containing acrylic humectant composite on the soil microflora
International Research Center BioEngineering, ITMO University, Kronverkskiy Prospekt, 49, RU197101 St. Petersburg, Russia
Acrylic derivative-based superabsorbents are widely used currently in agriculture as the soil conditioners, plant growth regulators, etc. Their usage has a positive effect on the growth and survival of the plants cultivated in the arid regions. However, the effects of hydrophilic acrylic polymers on the soil microbiocenosis still remain unknown. The influence of the moisture-absorbing acrylic acid-based hydrogels with different proportions of bentonite filler was studied on the soil microbiota. N,N-methylenebisacrylamide was used as a crosslinking agent. Acrylic hydrogels were synthesized by radical polymerization in an aqueous medium at a synthesis temperature of 45 °C during 4 hours. The application of hydrogel of the certain concentrations (1.0, 1.5, and 2.5% wt) into the soil did not cause significant changes in the total abundance of heterotrophic bacteria and the length of the fungal mycelium. The CO2 emission rates did not change after and during the application of the hydrogel), which indicated the same level of carbon mineralization in the soil with presence of acrylic bentonite-containing hydrogels. The nitrogen fixation rate decreased on the first day after hydrogel application; after 14 days, it was close to the control values. We assume the activity of nitrogen-fixing bacteria has though turned to the normal level.