Basal respiration and composition of microbial biomass in virgin and agroforest-reclaimed semidesert soils of the Northern Caspian region

Biological activity of mountain meadow subalpine soils of Central Caucasus

“…Analysis of the obtained respiratory indicators of the metabolic activity of microbial biomass (Table 2) shown that the value of BR and SIR is influenced by the content of organic matter in subalpine soils. Obviously, the combination of a high humic content with favorable physical properties in the upper horizons (0-10 cm) of soils of mountain-meadow ecosystems (Table 1) creates optimal conditions for the functioning of soil microorganisms, which was confirmed in the studies of other authors [22][23][24][25][26][27]. 1.…”

“…The early indicators of changes in the natural environment under the influence of anthropogenic factors in the soil can be indicators of biological activity, such as basal respiration (BR), which reflects the availability of soil organic matter for soil microorganisms, and substrate-induced respiration (SIR), which characterizes the activity of the soil microbial community. The study of the response of soil microbial respiration in the conditions of pasture ecosystems is reflected in a number of works [22][23][24][25][26][27][35][36][37][38][39][40].…”

“…The content of microbial biomass carbon (Cmic), determined using SIR method, is an important functional part of soil organic carbon, providing the main production of carbon dioxide by soils [22][23][24][25][26][27][28]. The soils of the natural mountain meadow ecosystems of the Republic, in accordance with the gradation [23], are distinguished by a very high level of Cmic content (Table 2), which characterizes them as soils with a high potential of microbial biomass.…”

“…The index of the ratio of microbial biomass carbon in the total organic carbon of the soil (Cmic / Corg) is considered as an ecophysiological parameter demonstrating the mobility and availability of soil organic carbon for microorganisms [22][23][24][25][26]. Comparative analysis of the Cmic / Corg ratios practically did not reveal any differences (only 9%, t = 1.87; P = 0.09) between natural and disturbed soils (Table 2).…”

“…Such a comparative analysis will make it possible to quantitatively assess the consequences of pasture load on the soil cover of mountain meadows. As follows from the literature [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], the most informative and objective biological characteristics of soils are humic content, respiratory indicators of the metabolic activity of soil microbial biomass, the activity of redox and hydrolytic enzymes. The presented complex of biological indicators reflects the most important aspects of the soil biological properties: genetic, microbiological and biochemical.…”