The features of the structure of semi-hydromorphic meadow-chernozem soils in the Central Chernozem region (Belgorod oblast) and in the Krasnodar territory are studied. Both regions are characterized by the dominance of chernozem soils, but with different specialization of grain farming. It was identified that the patterns of changes of the waterproofness of the structure vary considerably in the study soils. Ambiguous results of assessing the quality of the arable soils using classifications by different authors were obtained. It is shown that the determination of the degradation degree of arable soils by the absolute values of the structure parameters is incorrect. The structure of arable and fallow soils for each region was compared. The content of agronomically valuable fractions in the arable horizons of cultivated soils and humus horizons of fallow lands shows that there is no degradation of the structure in rice soils, and in meadow-chernozem there is weak degradation in the «plow sole».