The Floodwater-Soil System

Eive zones can be distinguished the floodwater standing on the soil per se, the floodwater-soil interface, the anaerobic bulk soil, the rhizosphere, and the subsoil. These are to some extent continuous with each other, and they are certainly linked so that the function of the system as a whole is greater than the sum of its parts. But they provide convenient boundaries for discussion. 

The subsoil at greater depths may be aerobic in well-drained soils with a perched water table owing to an impermeable layer—such as the traffic pan in ricefields or anaerobic in soils fhaf are poorly drained fhroughouf. If may provide significanf quantifies of nufrienfs to planfs growing in the soil if their roots can reach them. 

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This chapter describes the important micro- and macrobiological processes in submerged soil and the overlying floodwater. Processes in plants and their rhizo-spheres are discussed in Chapter 6. The microbiological processes are discussed first and then the additional complexities caused by macrobiological processes and the particular ecology of the floodwater-soil system. 

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