AN EVALUATION OF 3 FIELD TECHNIQUES FOR DETERMINING THE SATURATED HYDRAULIC CONDUCTIVITY OF LAYERED SOILS

Three field methods for determining the saturated hydraulic conductivity of a Corval sandy loam overlying a Ste. Rosalie clay, were evaluated at the Macdonald College Farm, Quebec. The techniques were: single auger hole method; use of water table drawdown and drain outflow data, in conjuction with the ellipse drainage equation; and use of water table drawdown and drainable porosity data. The latter two methods can be conducted only in fields with subsurface drainage systems. All three methods gave nearly equivalent results. The auger hole method produces rapid results under shallow water table conditions. The method utilizing water table drawdown and drain outflow data and the ellipse equation is useful for subirrigation design, and takes into account soil variability with depth and space. Furthermore, this method graphically illustrates flow components within each soil layer. The data are also in a format which could be utilized in water management models.