Nitrogen Cycling in Aerobic and Anaerobic Soils

Flooding and draining induce varying aerobic and anaerobic environments which alter N cycling in soils. By supplying excessive oxygen via draining, NH₄ conversion to NO₃ is accelerated. Reflooding then imposes an anaerobic condition where newly-formed NO₃ is lost through denitrification and leaching.

¹mineralization occurs slower in flooded (anaerobic) soils maintaining residual N supplies, and faster in non-flooded (aerobic) soils exposing N to potential loss.

²NH₄ (either as fertilizer N or residual N) is readily oxidized to NO₃ which at this point is vulnerable to loss via leaching and/or denitrification.

³NO₃ in oxygen-deficient soils replaces oxygen as the final electron acceptor in respiration of anaerobic microorganisms resulting in denitrification and N-loss.

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