Presence of Hydrophytic Vegetation

Under most conditions, oxygen release into rhizosphere should be adequate to oxidize excessive levels of reduced compounds in order for wetland plants to survive soil anaerobiosis. Release of oxygen into the rhizosphere is demonstrated by the observation of oxidation of Fe + to Fe + and precipitation on the root surface, oxidation of carbonaceous compounds, and nitrification of ammonium nitrogen. A detailed discussion on the fate of oxygen in the rhizosphere is presented in Chapter 6. 

By definition, all wetlands have hydric soils. However, land areas with hydric soil features may not support all functions of wetlands. With a broader definition, wetland soils can be divided into the following major groups  

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