NORMS OF CHANGE OF PHYSICAL PROPERTIES OF SOILS OF STEPPE, ARID AND SEMI-DESERT ZONES OF EUROPEAN RUSSIAN TERRITORIES

Norms of change of physical properties of arable land have been developed chernozems of steppe, chestnut soils of dry-steppe and light-chestnut soils of desert steppe zones of the European territory of Russia depending on the nature of anthropogenic impact. The limits of optimum, admissible and critical values of physical properties of these soils for growth and development of plants are established. For each zone, expert estimates of the distribution of soil areas with optimal, acceptable and critical values of the basic physical properties of soils are given. The greatest differences are observed in the density and structural composition of soils of different soil-climatic zones. In the steppe zone, soils with optimal values of arable layer density prevail among ordinary chernozems (1.0 - 1.2 g/cm3); among pre-Caucasian and southern chernozems - with values of 1.25-1.35 g/cm3. Among the chestnut soils of the dry-steppe zone the most common are the differences in the permissible values equilibrium density (1.30-1.40 g/cm3); in the desert steppe zone light chestnut soils with permissible (1.35- 1.45 g/cm3) and critical values (>1.45 g/cm3) of the equilibrium density. In the arable layer of soils of each separate zone agrophysical properties are significantly reduced by agrotechnical measures and close requirements of crops cultivated in the zone. Norms of change of physical properties can serve as a guide for assessing the current physical condition of arable soils and a basic basis for the development of regional fertility conservation and reproduction systems of the soil.