Microbiological and physical properties of skeletal soils used for tobacco growing

Galina Petkova, Kostadinka Nedyalkova, Jonita Perfanova, Milena Kercheva, Mariana Christova, Zhenya Ilieva

Abstract: The aim of the present study was to characterize the main microbiological and physical properties of skeletal soils near to the town of Gotze Delchev under oriental tobacco, and to analyze the interdependencies among the studied parameters. Content of total and organic C, pH, particle size distribution, bulk density, total porosity, aeration capacity, number of main morphological and physiological groups of microorganisms, CO2 evolution, amount of microbial biomass carbon and activity of β-glucosidase and phosphatase enzymes were assessed. The studied soils (Rendzina, Slightly and Medium Leached Cinnamonic Forest soils and Alluvial- Deluvial soil) differed in location, soil texture, degree of stoniness and hydraulic properties. It was established that skeletal soils had a similar structure of microbial populations and dominance of the processes of nitrogenous organic compounds immobilization but differed in their microbiological activity. Ammonifying bacteria were more abundant in soils with higher stoniness - Rendzina and Slightly Leached Cinnamonic forest soil. The high values of the number of cellulose-decomposing microorganisms, CO2 evolution and β-glucosidase activity in Rendzina and Alluvial-Deluvial soil indicated a more intensive mineralization of the organic matter in comparison with studied Leached Cinnamonic forest soils. The amount of microbial biomass C was positively correlated with some of the studied parameters - CO2 evolution, number of ammonifying bacteria and bacteria using mineral nitrogen, pH, clay and sand content. The activity of β-glucosidase and acid phosphatase were positively correlated with the volume water stored at potential pF1,7 (θpF1,7) and silt content.

Keywords: enzyme activity; microbiological properties; physical properties; skeletal soils; soil microorganisms

Date published: 2022-02-17