Monday, November 5, 2007
74-12
Comparison of Ninety Degree Surface Tension Test and Repellency Index as Measures of Soil Water Repellency.
David Moody, 116 AG Sciences & Industry Bldg, Pennsylvania State Univ., Penn State University, Dept of Crop and Soil Sciences, University Park, PA 16802-3504, Maxim J. Schlossberg, Penn State University, Dept. Crop & Soil Sciences, 116 ASI, University Park, PA 16802-3504, Michael Fidanza, PO Box 7009, Penn State Berks, Penn State University-Berks Campus, 2080 Tulpehocken Rd., Reading, PA 19610, and Andrew McNitt, 116 Ag Sciences & industry Building, Pennsylvania State Univ., Penn State University, Department of Crop and Soil Science, University Park, PA 16802-3504.
Soil water repellency (SWR) is an increasingly recognized edaphic phenomenon with serious implications to vadose zone processes. Several SWR evaluation techniques exist; each with limitations in terms of repeatability, resolution, cost, and accuracy. This study compared ‘ninety degree surface tension’ (γ90°) test and ‘repellency index’ (R) measurements on samples displaying varying degrees of water repellency. Both evaluative techniques were performed in replicate on sub-samples of oven dried (55°C) sands under controlled conditions. The following linear regression estimates R from γ90° values: R = 10(4.23 – 0.0518 γ90°), r2 = 0.734. These results indicate that R, which provides a precise, continuous, intrinsic measure of soil wettability, can be estimated from rapid, simple γ90° measurements in sand based rootzones.