Physical properties of ordinary chernozems in steppe landscapes adjacent to forests

The spatial changes in the ecological conditions of the humus formation; the humus content and reserves and its fractional-group composition and amphiphilic properties; and the structure, density, and water absorption coefficient of ordinary chernozems were studied on nine key plots at distances of 34 and 2 km from two forest massifs of different sizes??the Buzuluk Bor (111 000 ha) and a small birch grove (25 ha)??in the steppe zone of the Cis-Ural region. With an increase in the distance from the forests, the soil humus reserves decrease, the C_ha/C_fa ratio becomes larger, and the portion of hydrophilic and amphiphilicneutral fractions in the soil organic matter increases. In the same direction, the structure coefficient decreases (from 2.5?C3.7 to 1.5?C2.2), the soil density gradually increases, and the water permeability decreases and remains within the optimal values range.