In the course of different climatic cycles and the prolonged one in particular the biosphere including the plant and soil cover reveals considerable changes. Due to warming the cold six months and increasing the moisture in warm ones started in the 1970s the plant coenoses, the moisture regime and the whole calcareous profile have been highly changed in migration-mycelial chernozems of different ecosystems within the Kursk region. Based upon the long-term investigations (1947–2006) it seemed reasonable to conclude that during more than 30 years the above chernozems are found under conditions of the increased moisture which is not typical for them. As a result, their diagnostic features displayed great changes. The cyclic recurrence of their carbonate status has been determined as caused by cyclic climatic conditions and changes in plant coenoses and the moisture regime.

The group composition of humus in microaggregates (colloidal, pre-colloidal, fine, medium and coarse silt) of the soddy-podzolic medium-loamy soil has been first studied in three five-course grain-tilled crop rotations in the long-term experiment of V.V. Dokuchaev Soil Science Institute. It is shown that in the trial with a higher dose of fertilizers (N150P150K180 kg/ha/year + 120 t/ha of manure) the humus content increases in soil after the first rotation as compared to that with average fertilizer doses (N60P60K60). This is explained by the content of carbon bond to microaggregates of medium and coarse silt. At the same time both experimental variants reveal deterioration of the microstructure including the decrease in the content of medium silt, accumulation of pre-colloidal and fine-dispersed fractions. It becomes evident that the best microstructure is observed in the variant enriched with fertilizer: it contains a great amount of silty fractions and humus components in the form of humates and nonhydrolyzed residues. Moreover, both experimental variants show a tendency towards decreasing the content of humates bond to silty fractions. The intensive system of fertilization in three rotations allowed maintaining the stable content of humus in the fraction of medium silt, the latter being disturbed to a lesser extent than that in the variant without manure application.

The impoverishment of physical and water properties resulted from the use in agriculture for a long period of time is exemplified by soddy-podzolic, gray soils and chernozems. Alternation of natural (forest, meadow and steppe) coenoses by agrocoenoses leads to degradation of soils, impoverishment of their temperature and water regimes, water supply and water-supplying capacity as well.

, mobile forms of P and K (the latter effects considerably the soil fertility at lime doses of more than 0.50 Hг).

Under study are regularities in distribution of fractions <1, 1–5, 5–10 mkm and the mineralogical composition in agro gray forest loamy soils of Vladimir opolye. Spatial distribution of the above fractions is closely associated with regularities in zonal soil formation – typical agro gray forest soils reveal an eluvial-illuvial distribution type of the clay fraction, the latter being evenly distributed in agro gray residual carbonate soils. Silt fractions are uniformly distributed to be rather increased in plough horizons. The mineralogical composition of the fraction <1 mkm is represented by complicated disordered mica-smectite formations with different segregation of components of mica or smectite type in crystallites, hydromicas, kaolinite and chlorite. The ratio between mineral components shows considerable changes both horizontal and vertical along the soil profile. The second humus horizon is characterized by proportions of the main mineral phases and the smallest amount of the fraction <1mkm. Dominant are minerals of silt fractions including quartz, mica and potash feldspar.

For southern steppe regions of the country the soil protection technologies of crop production, being exemplified by chernozems in the Pre-Caucasus region have been elaborated and put into practice with the aim at increasing their productivity, fertility recovery and preventing the soils and crops against erosion processes. In the forest-steppe zone a set of soil protection measures including the contour organization of the territory, strip cropping, selection of soil amendment crops, soil biologization is used in agro-gray eroded soils on slopes (to 5º).