An Evaluation of Natric Soil Characterization Data in North Dakota: A Challenge for Contemporary Interpretation.

There are about 1.9 million ha of sodic soils in North Dakota, distributed across a variety of parent materials and subject to differing degrees of ground water influence and quality. There are about 330 soil series, of these 42 are natric and of these 7 have the Subgroup Glossic (47,200 ha), 13 are Leptic (388,000 ha), 13 are Typic (409,000 ha) and remaining are Aridic, Calcic, Torrertic, Vertic and Natric.  A dataset of 125 pedons sampled for progressive soil surveys, irrigation development, and thesis investigations from 1949 to 2009 were compiled for this study. Characterization data were collected from the USDA/NRCS Kellogg Soil Survey Laboratory and from North Dakota State University Agricultural Experiment Station. The major USDA taxonomic subgroups are Leptic, Glossic and Typic Natustolls and Natrudolls, with fewer Natraquolls. The objective of this research was to review the physical, chemical and taxonomic properties of these sodic soils, create flowcharts describing data completeness, and to determine data gaps and discrepancies. Of the 125 pedons, there are 37 Glossic, 27 Leptic, 43 Typic and 18 are other Subgroups. However, only 12 Glossic, 14 Leptic and 6 Typic pedons have complete data with respect to sodic soil properties on the basis of Handbook 60 criteria. In addition, there are 17 Glossic, 1 Leptic and 19 Typic Subgroups that fail to meet sodic criteria. Although much work has been done to characterize sodic soils in North Dakota, many of the characterization pedons do not have chemical data that either identifies these soils as being sodic (SAR, EC, pH) or chemical analyses were never determined. The ability to make comparisons even within respective soil series is challenged by a lack of complete data. Improved characterization and understanding of the genetic controls on sodic soils (i.e., physiography, parent material, ground water) will enable more targeted land management which will allow for improved vegetative production and potential remediation.