Biological Activity of Soils of Saline Complexes

Biological activity in transition zone between Haplic Solonetz and Ka­stanozem was studied. The research objects were located on natural pastures in dry steppe zone on the south of the East European Plain. Microbial biomass was estimated by the content of soil phospholipids, ratio of microorganisms of different trophic groups was determined, and enzymatic activity was studied using fluorogenically labeled substrates. Microbial biomass decreased with depth and was greatest in the upper layer of Solonetz confined to micro-depression of erosive nature. In upper horizon of other soils, the biomass was half as much. In Kastanozems, phosphatase activity dominated; in Solonetz, activity of leucine-aminopeptidase and arylsulfatase increased with depth. By biological activity, the upper horizon of eroded Solonetz was closest to that of Haplic Kastanozem and differed from Haplic Solonetzes. A pool of extracellular enzymes was active in natric horizon. According to the complex of biological indicators, the soil in transition zone between Haplic Solonetz and Ka­stanozem stood out sharply. Influence of solonetz process on soil biological activity is proposed to express by coefficients of biological differentiation of profile, showing the ratio biological activity in illuvial and eluvial horizons. According to it, the activity of leucine-aminopeptidase and arylsulfatase, as well as the number of CFU of cellulolytic fungi, were closely related to the intensity of solonetz process.