Microbiocenosis characteristics of agrogenically altered acid brown forest soils in humid subtropics of Russia

Federal State Budget Scientific Institution «Federal Research Centre the Subtropical Scientific Centre of the Russian Academy of Sciences», 2/28 Jānis Fabriciuss, Sochi, 354002, Russia ;

^* Corresponding author: RogojinaEW@yandex.ru

Abstract

Under conditions of perennial cropping of industrial tea crop on acidic brown forest soils of the Black Sea coast of Russia, the following were investigated: number of bacteria, of actinomycetes (mainly the Streptomyces genus) and of micromycetes (saccharomycetes), seasonal dynamics and functional activity of the microbial complex during period of 2008-2019. Stationary experiments were launched in various backgrounds of mineral fertilizer application. The experiment was accompanied by the use of generally accepted recommended techniques for microbiological studies. As follows from the analysis of the data obtained, it was established that the long treatment period of mineral fertilizers at doses from N200P60K50 to N600P180K150 in given soil-climatic conditions under the tea crop contributed to significant decrease in the number of actinomycetes and nitrogen fixing bacteria of the Beijerinckia genus vs. the control variant (without fertilizers). The most significant decrease in the number of micromycetes was revealed immediately after the application of mineral fertilizers at a dose of N600P180K150. After 2 months, the number of this group of soil microorganisms was built back. Under the impact of both medium and high doses of mineral fertilizers, the functional activity decrease of soils (CO₂ emission and potential nitrogen fixation activity) was noted.