This study focuses on differences in the soil water regime in a coarse‐loamy, closed, till landscape with sodic soils. Problems of classification of sodic soils are difficult to resolve in the field. Our basic hypothesis was that greater emphasis on soil water regime would improve classification of sodic soils. Three landscape positions were studied that reflect internal drainage differences: (i) a well‐drained upland position; (ii) somewhat poorly drained intermediate position; and (iii) a poorly drained seasonal wetland. We classified and studied more than 50 profiles at each position. Six pedons were selected from trenches for detailed study. Pedons were analyzed for extractable ions, electrical conductivity (EC), pH, exchangeable sodium percentage (ESP), dispersible clay, and particle size. The upland position had soils with Na‐induced clay illuviation Natriborolls. They lacked glossic morphology. The nonsodic soils at the upland position were Haploborolls. The soils at the intermediate and wetland positions were classified as Natriborolls and Natraquolls, respectively. A shallow water table exerted a stronger influence on soil development at the two positions than at the upland position. Field or laboratory evidence does not justify using the Glossic Udic Natriboroll taxon at the upland position. B‐horizon structure and substrata colors and mottling are better criteria to recognize that the upland sodic soils are different. Sodic soils at the intermediate position should be recognized in a new subgroup, Aquic Natriborolls. The aquic subgroup would effectively discriminate between the moderately well‐drained upland soils and the somewhat poorly drained intermediate soils. Sodic soils with high‐surface salinity were an integral part of the sodic soils complex at all three landscape positions. The Leptic subgroup recognizes these soils; however, it does not differentiate between sodic soils with different soil water regimes. We suggest that sodic soils with high‐surface salinity be differentiated as saline phases of soil series rather than a separate subgroup.
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