The influence of granulometric composition on agrophysical properties of virgin gray forest soils of the Northern Trans-Urals

The article is based on data on 330 full-profile sections of undisturbed gray forest soils, covering all subtypes, performed by employees of the Department of Soil Science and Agrochemistry of the SAU of the Northern Trans-Urals on the territory of the south of Tyumen region. The purpose of the study was to examine the variation in the agrophysical properties of gray forest soils in the context of varieties in terms of granulometric composition (the content of elementary soil particles no larger than 0.01 mm). The density of soil structure was determined in the field according to Kachinsky, the density of the solid phase was determined in the analytical laboratory by the pycnometric method, and the total porosity was calculated. The compartmentalization of soils was carried out according to the Kachinsky method. The results of the field studies and laboratory analyzes were grouped by variety and visualized using boxplot charts in a Microsoft Excel 2016 spreadsheet processor. It was revealed that soils of light granulometric composition dominate in the type of gray forest soils, which account for 44%. This fact is explained by the high content of fine sand in soil-forming rocks. The proportion of heavy varieties is 38%. A tendency has been established for a decrease in the density of soil structure of the A1 horizon of virgin gray forest soils from 1.19 to 1.08 g/cm3 from sandy to heavy loamy varieties, which is associated with an improvement in the humus state and soil structure. The total porosity has an opposite trend: it increases from sandy to heavy loamy soils from 46 to 55% of the soil volume. The regularities of changes in the density of the solid phase depending on the granulometric composition of gray forest soils have not been revealed.