Comparison of One-step Outflow Laboratory Method to an in situ Method for Measuring Hydraulic Conductivity1
- D. B. Jaynes and
- E. J. Tyler2
The unsaturated hydraulic conductivity, K, of three soil horizons; the C horizon of a Plainfield sand (Typic Udipsamment), the C horizon of a Ringwood silt loam (Typic Argiudoll), and the B2t horizon of a Plano silt loam (Typic Argiudoll) was measured using a variation of the one-step porous membrane outflow method. The method was adapted for measuring K using small (7.65 cm high by 7.65 cm in diam) undisturbed soil cores at soil water pressure potentials > −100 mbars. Comparison of these K values with values previously measured in situ for the same horizons with the crust test agreed within an order of magnitude or less. The discrepancy was probably due to hysteresis in the θ-ψ relation.
The one-step outflow method yields satisfactory results near saturation but cannot be used to measure saturated K values. Compared to other methods, the one-step outflow procedure requires less time to measure K for many types of soils and facilititates the running of many samples simultaneously.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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