Katherine C. Akstin John R. Nimmo 1988 <p><span>To investigate the degree to which compaction of a sandy soil influences its unsaturated hydraulic conductivity </span><i>K</i><span>, samples of Oakley sand (now in the Delhi series; mixed, thermic, Typic Xeropsamments) were packed to various densities and </span><i>K</i><span> was measured by the steady-state centrifuge method. The air-dry, machine packing was followed by centrifugal compression with the soil wet to about one-third saturation. Variations in (i) the impact frequency and (ii) the impact force during packing, and (iii) the amount of centrifugal force applied after packing, produced a range of porosity from 0.333 to 0.380. With volumetric water content θ between 0.06 and 0.12, </span><i>K</i><span> values were between 7 × 10</span>⁻¹¹<span> and 2 × 10</span>⁻⁸<span> m/s. Comparisons of </span><i>K</i><span> at a single θ value for samples differing in porosity by about 3% showed as much as fivefold variation for samples prepared by different packing procedures, while there generally was negligible variation (within experimental error of 8%) where the porosity difference resulted from a difference in centrifugal force. Analysis involving capillary-theory models suggests that the differences in </span><i>K</i><span> can be related to differences in pore-space geometry inferred from water retention curves measured for the various samples.</span></p> application/pdf 10.2136/sssaj1988.03615995005200020001x en Soil Science Society of America Hydraulic conductivity of a sandy soil at low water content after compaction by various methods article