Comparison of Spatial Variability of Infiltration Properties at Two Sites in Konza Prairie of East-Central Kansas

Abstract

The spatial variability of soil hydraulic properties that govern infiltration were investigated at two sites in the Konza Prairie Research Area in Kansas. One site was a pristine prairie site with native grass, and the other was a continuously cropped agricultural site from which wheat had been recently harvested. Soil hydraulic properties studied were saturated hydraulic conductivity, matrix flux potential, soil sorptivity, and pore-size distribution parameter. Spatial variability was assessed through semivariograms that were constructed based on 37 measurements at each site using the Guelph Permeameter. Correlation lengths of the infiltration properties varied from 1 to 4 m. Sorptivity was found to be lognormally distributed. The spatial structure of infiltration properties at both sites exhibited pseudoperiodicity and a hole-effect variogram model was used. Infiltration properties at the agricultural site indicated multiple peaks in the variograms. Implications of these results on computing areally averaged infiltration at the two sites are discussed.