2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 22
Presentation Time: 8:00 AM-6:00 PM

Evaluation of Portable X-Ray Fluorescence for Gypsum Quantification In Soils

WEINDORF, David1, ROLONG, Nelson2, FERRELL, Ray3, ALLEN, B.L.4, HUDNALL, Wayne5, HERRERO, Juan6 and ZHU, Yuanda1, (1)School of Plant, Environmental and Soil Science, LSU AgCenter, Baton Rouge, 76803, (2)USDA-NRCS, Soil Science Division, Little Rock, AR 72201, (3)Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, (4)Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, (5)Plant and Soil Science, Texas Tech University, MS 2122, Lubbock, TX 79409, (6)Departamento de Suelo y Agua, Estación Experimental de Aula Dei, C.S.I.C, Apartado 13034, Zaragoza, 50059, Spain, dweindorf@agcenter.lsu.edu

The use of field portable x-ray fluorescence spectrometry was evaluated as a quantification tool for gypsum content in soils of West Texas and Eastern New Mexico, USA. Six sites were evaluated with gypsum contents ranging from <10% to >90%. Samples collected from each site were scanned in the field using XRF, then brought back to the lab for additional XRF scanning. Variables which might affect XRF scanning results, such as scanning time, particle size, moisture content, etc. were evaluated. Both gypsum (CaSO4•2H2O) and calcite (CaCO3) were quantified using standard lab techniques. Correlation of gypsum XRF data (via Ca quantification minus CaCO3 content) and lab data showed a strong correlation. Field portable XRF shows considerable promise as a rapid, quantifiable measure of gypsum in soils.