| Abstrakt: |
Hydric soils are identified on-site using morphological features called "field indicators". It is not known how long it takes for these indicators to form, nor whether they occur in created wetlands inundated for approximately 5% of the growing season, which is the minimum duration needed to meet wetland hydrology requirements. This study evaluated formation of redoximorphic features and hydric soil field indicators under field conditions following controlled, short-term floods that produced ponding events. A flood plain was constructed along an artificial stream channel (100-m long) where flooding was controlled by dams at each end of the channel. Floodwaters inundated soils on the flood plain nine times over a 3-year period. Ponded water was kept on the soils for periods ranging from 4 to 44 days. During ponding events, Fe2+ concentrations were approximately 1 to 4 mg/L, which indicated that the soils were anaerobic and undergoing Fe reduction. Redox depletions formed in A horizons following a single 7-day ponding event. Abundance of depletions increased from 2% to an average of 15% after nine ponding events. Most depletions were approximately 1 cm in diameter and had Munsell hues of 2.5Y and 5Y, values of 4, and chromas of 2 or less. The depletions appeared to form in place by loss of both Fe and C. Hydric soil field indicators developed in all plots after nine ponding events over a 3-year period and included the depleted matrix, redox dark surface, and a variant of the depleted dark surface. All indicators formed by a reduction and/or oxidation of Fe. [ABSTRACT FROM AUTHOR] |
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