Biological activity in the forest floor of artificial forests in the steppe zone
Authors: Maltsev Ye. I. 
Published: February 2020

A special role in the biological cycle in forest biogeocoenoses plays forest floor, which connects the abiotic and biotic components in an integral system, affects the genesis of forest soils and productivity of forest plantations. The most informative indicators of biological activity of the soil and the forest floor are the activity of enzymes, the intensity of carbon dioxide emissions, the number and qualitative composition of the main groups of microorganisms. Particular specificity of these indicators acquire in artificial forest plantations in the steppe zone, due to the geographical, ecological and often a mismatch in habitat conditions for forest. The aim of this work was to study the biological activity of the forest floor in artificial forest plantations in the steppe zone of Ukraine (on the example of Staro-Berdyansk forest). Staro-Berdyansk forest (Zaporizhia region, Ukraine), founded in 1846 on the left bank of the Molochnaya river. Studies of the biological activity the forest floor carried out on stationary plots in stands of Quercus robur L., Robinia pseudoacacia L. and Pinus pallasiana D. Don during 2013 year seasonally. Analysis of the data series using correlation method showed that the increase in the forest floor the magnitude of algae, micromycete and oligotrophic microorganisms is accompanied by an increase in catalase activity (correlation coefficients: 0,80; 0,91; 0,95), at the same time micromycete and oligotrophs positively associated with thermolabile component of catalase activity (correlation coefficients: 0,75; 0,95). In periods of reduction of catalase activity increases the number of actinomycetes (r = -0,67). Polyphenol oxidase activity is positively correlated with the magnitude of micromycete in the forest floor (r = +0,68) and negatively with the population of actinomycetes (r = -0,86) and bacteria, that use mineral nitrogen compounds (r = -0,69). In periods of activation of phosphatase the magnitude of algae and micromycete decreases (r = -0,92 and r = -0,80; respectively) and cellulolytic microorganisms increases (r = +0,75). Integral indicator of biological activity of the forest floor is the amount of carbon dioxide emitted, indicating the intensity of the processes of transformation of organic matter. The greatest intensity of carbon dioxide emissions recorded in autumn samples of locust bean and pine plantations. The oak stands a high level of carbon dioxide emissions occur in summer and autumn. The magnitude of microorganisms and algae, enzyme activity and the intensity of carbon dioxide emissions in the forest floor changed by seasonal, which corresponds to the dynamics of the overall progress of biological processes occurring in the forest floor. On the biological activity of the forest floor is significantly affected by the composition of plant residues, which generally corresponds to the views of various researchers who have noted a correlation of enzyme activity in the soil with the magnitude of microorganisms, as well as biochemical and chemical composition of forest floor and the stages of its destruction.