Moisture security. Rainfall and temperature condition of the period of active vegetation create conditions of moisture security of crops which are estimated by hydrothermal coefficient (State Customs Committee).
The soil is the most difficult bioinert system formed as a result of close interaction of natural factors in time. Remaining the basic and irreplaceable means agricultural productions, soils in too time acts and as one of the main components of a biogeocenosis, and consequently, and biospheres in general. Agricultural use in the soil is resulted by the deep, and at times irreversible processes transferring the soil environment to other qualitative state. Being in indissoluble unity with other components of an ecosystem, anthropogenically transformed soil changes the communications and ratios with them. Important and to it is necessary to know, in what direction it is blown modern evolutionary processes in soils.
These distinctions well are confirmed by the maintenance of fractions 1, 2, 3 in acids. In sandy chernozems it makes 45-52 for the first, 34-41 for the second and 11-14% for the third, whereas in chernozems of heavy particle size distribution these indicators of are as follows: 9-14, 64-77 and 11-20%.
Secondly, at a depth of 2-Z m increase of the maintenance of sandy fractions and relief of particle size distribution that is connected with heterogeneity of pochvoobrazuyushchy breeds is noted. Thirdly, in the horizon In the small accumulation of oozy particles caused lessivazhy by an oglinivaniye of beskarbonatny breed due to aeration of primary minerals is traced.
Slightly more often in steppe and forest-steppe parts of the considered region neogenovy clays act as pochvoobrazuyushchy breeds. For them greenish and olive color, considerable calcareousness, prizmovidny structure are characteristic. In a damp state they become sticky, viscous. Neogenovy clays contain 60 — 80% of physical clay and 45 — 55% of silt. Dense clays of the Neogene at a close bedding to a surface create geochemical barriers on the way of the descending streams of solutions, accumulate salts promote formation of solonetzic soils, solonetzic soils, solody.