The accumulation of heavy metals in the environment can contribute to soil homeostasis disturbance. However, their adverse effect can be reduced by introducing neutralizing substances to soil. Therefore, an experiment was carried out to determine the effect of varied doses of zinc on the microbiological and enzymatic properties of soil. Additionally, the neutralizing effect of liming applied to zinc-contaminated soil was evaluated with regard to the microbiological and biochemical properties of the soil. Loamy sand of pHKCl 5.6 was used as the soil material. Calcium carbonate was applied in doses neutralizing the hydrolytic acidity of soil, which amounted to 0, 1 and 2 HAC, respectively. Next, zinc (ZnCl2) was introduced to soil, in the amounts of 0, 250, 500, 750, 1000 and 1250 mg kg-1 DM of soil. In weeks 2 and 20 of the experiment, the counts of microorganisms (organotrophic bacteria, copiotrophic bacteria, oligotrophic bacteria, actinomycetes and fungi) and activity of enzymes (dehydrogenases, catalase, urease, acid phosphatase, alkaline phosphatase and β-glucosidase) were determined in soil samples. Based on observations of the proliferation of microorganisms, changes in the diversity of the soil microbiome exposed to zinc were evaluated with the use of the colony development (CD) index and ecophysiological biodiversity (EP) index. Excessive amounts of zinc demonstrated a negative effect on the biological parameters of soil. It brought about a reduction in the count of microorganisms, although the highest resistance to zinc was demonstrated by copiotrophic bacteria and fungi. Additionally, this element revealed an inhibitory effect on the activity of soil enzymes and colony development index, as well as on the ecophysiological biodiversity (EP) index of microorganisms. The addition of calcium carbonate to the soil neutralized the negative effects of zinc on its microbiological and biochemical properties.

22.3.2017