Scaling the saturated hydraulic conductivity of an alfisol

Abstract

Alfisols exhibit a high degree of spatial variability in their physical properties. As a result, it is difficult to use information on physical parameters measured at one location to model larger-scale hydrologic processes. In this study, the saturated hydraulic conductivity, K,, of an Alfisol was determined on 109 undisturbed monoliths using the falling-head permeameter method. The model developed by Arya & Paris (1981) was used to calculate the pore volume from sand and clay fractions. Scaling factors were calculated from the measured K,, sand pore-volume, clay pore-volume, clay content and effective porosity, using the similar media concept. Prediction of K, of gravelly Alfisol using clay pore-volume is confounded by high gravel content which, when discounted, improves the prediction remarkably. The scaled mean saturated hydraulic conductivity K* for all horizons of the Alfisol was approximately I .O x m s-'.

A study of a texture-based equation for estimating the saturated hydraulic conductivity of an alfisol in the sudan savannah ecological zone, Ghana

“…In reality, fitting a statistical functional relationship between K s and texture per se has proved very unsuccessful in many instances. For example, Puckett et al (1985) as well as Bonsu & Laryea (1989) reported a significant correlation between K s and sand or clay, but failed to establish any statistical functional relationship between them. Other researchers such as Aronovici (1946), Talsma & Flint (1958), Winneberger (1974), Gumbs (1974) and Varallyay (1974) have also reported significant correlations between texture and K s or permeability.…”

“…To check further the efficacy of equation (3), some K s data obtained in an alfisol (Udic rhodustalf) at the ICRISAT Centre, Patancheru, India (Bonsu & Laryea, 1989) were compared with those calculated by equation (3). Only data for non-gravelly samples were used for the comparison, since the gravelly and stony samples gave erratic and inconsistent results.…”

“…Three cores 76 mm x 76 mm were obtained at three depths in each profile. The saturated hydraulic conductivity measurements were made on the cores in the laboratory using the falling head permeameter method similar to that described by Bonsu & Laryea (1989). In the measurement, a cylinder of the same diameter was fitted to the top of the core to allow imposition of a hydraulic head.…”

“…Moreover, K s is one of several soil properties which are strongly influenced by spatial variability (Bonsu & Laryea, 1989). Many attempts have been made to estimate K s from easily-measured soil properties such as texture (King & Franzmeier, 1981;McKeague et al, 1982) and pore size distribution (Marshall, 1958).…”

“…Therefore, the objective of this study was to demonstrate the efficacy of a texture-based empirical equation presented by Rawls et al (1982) to predict K s of an alfisol near Bawku in the upper east region of Ghana. To check further the performance of the equation, a comparison was sought using some K s data on another alfisol at ICRISAT Centre, Patancheru, India (Bonsu & Laryea, 1989).…”