Field Truthing of United States Department of Agriculture-Natural Resources Conservation Service Soils Survey

Book excerpt: Soils of Tarleton State University's Hunewell Ranch in Erath County, Texas were sampled and physical and chemical laboratory analyses were performed. Results were then compared to existing Soil Survey Geographic (SSURGO) data. A total of one hundred sixty-six samples were collected representing twelve soil series. These samples were analyzed and compared to SSURGO data to determine areas within the study that demonstrated a weak correlation between datasets. Parameters compared were color, coefficient of linear extensibility, slope, texture, and soil reaction. Areas showing weak correlations were texture and soil reaction while color, coefficient of linear extensibility, and slope exhibited strong correlations between analyzed samples and SSURGO data. Areas displaying the greatest amount of error were erosional areas and transitional areas between map unit boundaries. Further studies should be conducted to determine the extent of transitional areas.