Flooded soils, also known as hydric soils, form when soils are saturated with water for a sufficiently long time each year, resulting in gley horizons from oxidation-reduction processes. Flooded soils have three zones - an upper partially oxidized organic matter-rich zone, a mottled middle zone where oxidation and reduction occur, and a lower permanently reduced bluish-green zone. Physical, chemical, and biological changes occur in flooded soils, including soil compaction, puddling, accumulation of gases like carbon dioxide, and changes in redox potential and pH. Management of flooded soils involves drainage installation, controlled irrigation, crop selection, and planting of trees with high transpiration rates to remove excess water.