Encyclopedia
Chernozems
Chernozems are soils with a content of humus and decomposed plant residues reaching up to 10% in the upper layer, characterized by granular and crumbly structure. Chernozem contains a large amount of silty and clay particles, is distinguished by high water retention capacity, stickiness, plasticity; upon moistening it swells sharply and reduces compressive strength
Source: "SN 449-72. Construction Norms. Guidelines for Designing Earthworks for Rail and Roadways"
(approved by the State Construction Committee of the USSR on December 29, 1972)