Hydraulic Conductivity Measurements Close to Water Saturation for Soil Structural Evaluations.

Although in-situ measurements of soil hydraulic conductivity may be a better representation of ‘real world’ conditions, sometimes circumstances prevent these measurements from being performed in the field.  To accommodate for these predicament, intact soil cores are generally taken as representative samples for laboratory analysis.  Measuring hydraulic properties in most laboratories, however, can be problematic as well.  Room temperature and pressure can rapidly fluctuate due to building controlled environmental systems as well as the opening and closing of laboratory doors.  These conditions may cause drastic pressure changes particularly in Marriott devices used for dispensing water.  The use of U-manometers greatly helps to increase the precision of both the upper and lower boundary conditions by allowing constant monitoring of the internal pressure at the point where water is applied to the sample.  Intact soil cores of contrasting structural properties were taken for measurement on laboratory disc infiltrometers.  Samples were collected from a sandy textured Ap horizon with little structure, a silt loam textured Ap horizon with good structure and two clayey textured B horizons, also with good soil structure.