Study of inorganic carbon reserves in an arid climate

An assessment of the reserves of inorganic carbon (SIC) in the soils of the dry-steppe zone of the Volgograd region on the territory of the Nizhnevolzhskaya station for breeding tree species (branch of the Federal Research Center for Agroecology of the Russian Academy of Sciences, Kamyshin city) was carried out. The study was conducted for soils of two biogeocenoses: under forest vegetation (protective forest plantations, dry pine forest) and natural steppe vegetation (postagrogenic soils of the dry steppe). The samples were taken from 31 soil sections in 10-centimeter layers to a depth of 150 cm. A total of 180 soil samples were examined. The content of carbonates and bicarbonates, as well as density, humidity, pH, and organic matter content in the soil were determined in the samples. The soils are assessed as compacted, extremely poor in the presence of soil moisture and organic matter. A significant spatial variability of the carbonate content (more than 200%) under forest vegetation has been established. According to the content of carbonates and pH, the soils are divided into four clusters, one of which includes statistical “emissions”. Significant differences in the reserves of inorganic carbon in the soils under forest and steppe vegetation are noted. Reserves of inorganic carbon in the 0-150 cm layer under dry pine trees leave 25.2±9.5 tons ha-1, under steppe vegetation – 54.2±16.7 tons ha-1, which is 2.1 times higher. The inorganic carbon in the studied soils is in the form of calcium carbonates and bicarbonates. The main reserves of inorganic carbon for both biogeocenoses are recorded in the soil from a depth of 50 cm.