When a soil is submerged, water replaces the air in the porous spaces. Except in a thin layer on the soil surface and sometimes a layer under the sole of the plow, most of the soil layers are practically free of oxygen within hours of the dive. The diffusion of oxygen in the layer of water above the ground is very slow and the rate of consumption of O2 is reduced the soil is high.
The only electrochemical property that serves to distinguish a submerged soil from a well drained soil is its redox potential. The redox potential of a soil or sediment provides a rapid, useful and semiquantitative measure of its oxidation-reduction state. Two recent developments have stimulated interest in the chemistry of submerged soils: breeding lowland rice varieties with high yield potential and contaminating streams, lakes and seas by domestic, agricultural and industrial wastes. The chemistry of submerged soils is valuable:
A) understanding soil problems, limiting yields of high-yielding rice varieties and
B) evaluate the role of lacustrine, estuarine and oceanic sediments as nutrient reservoirs for aquatic plants and as sinks for landfills.