Scaling Approaches to Evaluating Spatial Variability of Saturated Hydraulic Conductivity and Cumulative Infiltration of an Acrisol

Abstract

Spatial variability of soil properties has been frequently assessed using classical statistics and geostatistics. However, the scaling theory approach has also proven to be an effective method to describe the variation of soil hydraulic properties. The objective of this study was to evaluate the structure of spatial variability in soil hydraulic and hydrologic processes using scaling techniques in the Plantations Section of the Department of Crops and Soil Sciences, KNUST, Kumasi. Field infiltration studies were conducted using the single ring infiltrometer. Saturated hydraulic conductivity (Ks) was determined in the laboratory by the falling head permeameter. The similar media theory approach was employed in the scaling of Ks, while cumulative infiltration amount (I) was scaled using the linear variability theory. Scaling factors and parameters of the reference curves were computed directly from the parameters of individual soil hydraulic and hydrologic parameters and reference curves were obtained to represent Ks and I in the field. Scaling factors ranged from 0.23 to 2.66 with a mean of 1.00 for Ks, I and cumulative time. The composite Ks and I for the study area calculated by using different, but related, scaling factors was successful, though the distribution and range of the parameters were highly variable.