Using Ground‐Penetrating Radar to Study Soil Microvariability

A 9‐ by 10‐m grid with observation sites 1 m apart was constructed on a mapped area of Sapelo (sandy, siliceous, thermic Ultic Haplaquods) soils to determine microvariability of depths to spodic and argillic horizons in a representative Atlantic Coast Flatwoods area. Ground‐penetrating radar (GPR) was compared with conventional field techniques to obtain the necessary data. Results indicated that the entire study area had a spodic horizon at an acceptable depth for the Sapelo series, but only 79% of the study area had an argillic horizon below the necessary 1‐m depth. Computer‐generated diagrams and maps can be used to select the most representative pedon for sampling, to display the variability of diagnostic subsurface horizons and surface elevation, and to characterize the composition of map units. Field time was reduced substantially when the GPR was used to obtain the necessary field data compared with conventional soil survey methods.