Abstract : Microbial activity plays an important role in regulating soil fertility. The aim of this study was to investigate dynamics of the number of microorganisms and dehydrogenase activity in the rhizosphere of maize in long–term monoculture. The study was conducted in the multi–year stationary field experiment. The study treatments were: control variant-without fertilizer; NPK-fertilized with mineral fertilizers; NPK + manure - with application of manure and mineral fertilizers; NPK + crop residue- with plowing crop residues (maize) and the application of mineral fertilizers. Soil samples were taken for microbiological analyses at two dates. The number of microorganisms was determined by the dilution method on agarized selective medium. Dehydrogenase activity was determined spectrophotometrically. The highest number of azotobacter and fungi was obtained on variant NPK. The highest number of cellulolytic bacteria and actinomycetes was on variant manure + NPK and crop residue + NPK on first date of sampling. On second date of sampling we obtained higher total number of microorganisms, number of azotobacter, amonifiers and fungi. The dehydrogenase activity was higher at the second date of sampling, too.

maize, microorganisms, long-term experiment, monoculture

Presentation: oral