Monday, November 13, 2006

Evaluation of a Pedotransfer Function Approach for Estimation of Saturated Hydraulic Conductivity.

Meghan Buckley Zeimen1, Gerard Kluitenberg1, and Philip Schoeneberger2. (1) Kansas State University, 2004 Throckmorton Plant Sciences Center, Manhattan, KS 66506, (2) USDA-NRCS, Lincoln, NE 68508

Knowledge of saturated hydraulic conductivity (Ks) is necessary for many site use interpretations.  However, Ks is rather difficult and time consuming to measure.  Pedotransfer functions include soil properties often measured in the field during site determinations and can be used with Rosetta, a Windows® program, to estimate Ks.  This study compared Ks values measured in the field and laboratory with Ks values estimated from Rosetta in three horizons from five benchmark soils using linear regression.  A pit was excavated at a representative site for each soil.  Field measurements were done on location while samples were collected for laboratory work.  Field measurements were done using a constant-head well permeameter.  Laboratory measurements used permeameters on large undisturbed cores obtained from the benchmark sites following both constant-head and falling-head methods.  Inputs to Rosetta were also obtained from the representative sites and included texture, sand, silt, and clay percentages, bulk density, 1/3 bar water content, and 15 bar water content.  The soils series used, Harney, Irwin, Pratt, Albion, and Ulysses, are all common to Kansas.