Determination of An Appropriate Quantity of In Situ Measurements to Effectively Evaluate Ksat for Soil Map Units.".

A recurring question for any type of field measuremnent is "How many determinations are sufficient?".  In situ saturated hydraulic conductivity (Ksat) determinations were made at 10 sites for each of two soils, scattered across their geographic range in KS and NE: an upland till soil (Burchard – fine-loamy, mixed, superactive, mesic Typic Argiudoll) and a floodplain alluvial soil (Kennebec - fine-silty, mixed, superactive, mesic Cummulic Hapludolls).  At each site, multiple in situ measurements of Ksat were made using the Amoozemeter method for each of 3 - 4 major horizons.  Multi-scale statistical analyses were used to evaluate the variability of Ksat both within and between sites.  A power analysis was used to determine how many "replications" were sufficient to adequately assign Ksat values to major layers for the associated map units.