Influence of seasonal dynamics on the microflora of two types of forest soils - Brown forest soils and Mountain-meadow soils

Bilyana Grigorova-Pesheva

Abstract: Microbial communities in forest soils play an important role in the functioning of the entire ecosystem. Soil microorganisms are one of the major units in the nitrogen cycle. Changes in the nature of microbial communities may lead to changes in the dynamics of uptake and conversion of nitrogen compounds into soil. Seasonal changes lead to fluctuations in soil microbiota. This study investigates the effect of seasonal dynamics on the microflora of Dystric-Eutric Cambisols and Modic Cambisols in the Vitosha Nature Park. Soils in four test areas were investigated, determining the total microbial number of the heterotrophic microflora, as well as the structure of the microbial communities. The dominant spore forming bacteria were determined by PCR analysis. The total microbial number of the samples tested as well as the number of the individual groups of microorganisms shows distinct differences across seasons. There are two distinct peaks - in the autumn season, where the total microflora in the studied areas varies between 9,1х105 - 2,5х106 CFU/g abs.dry soil and in spring, where the reported values are between 6,8х105 – 1,6х106 CFU/g absolute dry soil. These differences are mainly due to the change in temperature and the amount of fresh litter that falls on the soil surface.

Keywords: Dystric-Eutric Cambisols; Microorganisms; Modic Cambisols; PCR analysis; seasonal dynamics

Date published: 2020-05-14