WATER TABLES IN PAIRED ARTIFICIALLY DRAINED AND UNDRAINED SOIL CATENAS IN IOWA

This study was initiated to study water table fluctuations and the inf luence of artificial drainage on soil morphology. Water table depth an d duration for one artificially drained and one undrained soil sequenc e on paired landscapes were measured. Landscapes were composed of six soil series: Clarion (Typic Hapludolls); Nicollet (Aquic Hapludolls); Webster (Typic Haplaquolls); Canisteo (Typic Haplaquolls); Harps (Typi c Calciaquolls); and Okoboji (Cumulic Haplaquolls). Morphological prop erties of paired soil series were compared and related to water table fluctuations. Soil morphology and water table depth and duration were highly correlated for the Aquolls in the undrained traverse but not in the artificially drained traverse. Webster, Canisteo, Harps, and Okob oji in both traverses have endosaturation, contain redoximorphic featu res, and meet the criteria of hydric soils. In the undrained traverse, Okoboji meets the additional requirements of vegetation and hydrology , and qualifies as a wetland, while Webster, Canisteo, and Harps class ify as farmed wetlands. Webster, Canisteo, Harps, and Okoboji in the a rtificially drained traverse met the criteria of prior converted cropl and. A drained phase should be recognized for Webster, Canisteo, Harps , and Okoboji. We suggest that all soils with water table depths modif ied by artificial drainage have a separate soil interpretation record and be recognized as a drained phase. This proposed change would help reduce confusion in the use of data recorded on the soil interpretatio n record.