Floodplain Soil

a soil formed on the alluvial deposits of the floodplains of major rivers. Floodplain soils are distinguished by the presence of a large number of organisms, stratification, and the existence of buried humus horizons.

Varying processes of soil formation yield different types of floodplain soils. Soddy soils form beneath grass-forb meadows and light forests along floodplain levees and ridges. They are distinguished by a light texture and an unstable water regime resulting from high water and precipitation. Meadow soils form in the central part of the floodplain beneath forb-grass vegetation, where the surface and capillary fringe have a great deal of moisture. They are characterized by significant humus accumulation, grainy structure, development of gley in the lower horizons, and new hydrogenic formations (for example, ferromagnesium). Marsh soils form in the part of the floodplain near the terrace beneath grassy and wooded (alder) marshes and are confined to negative landforms (for example, depressions). They are distinguished by silting and bog formation. In the forest zone, there is intensive development of gley, and in the forest-steppe, steppe, and desert zones, the soils become impoverished by salin-ization and insufficient lime content.

Floodplain soils are found in diverse natural zones. They are fertile and are used as meadowlands and for raising vegetables, feed crops, rice, and other crops. Floodplain soils require regulation of water conditions (drainage and irrigation).