Assessing Quality of Citizen Scientists’ Soil Hand Texture Estimates.

Estimating soil texture is a universal and fundamental practice applied by soil scientists to classify and understand the behavior and management of soil systems. While trained soil scientist can often accurately estimate soil textural class, percent sand, and percent clay, doubt is sometimes cast on the quality of texture estimates produced by citizen scientists or inexperienced seasonal resource scientists tasked with conducting federal lands resource inventories. In our study, we compare analysis of texture-by-feel and laboratory derived soil texture classes of professional soil scientists using the USDA-NRCS National Soil Characterization Database of professional soil scientists as well as seasonal scientists working on federal inventory and assessment programs in Namibia and the Western United States. Analysis of texture accuracy was compared using confusion matrix analysis to evaluate user and classification accuracy. Our results showed that professional soil scientists demonstrated 66% absolute accuracy while seasonal field scientists demonstrated 38% absolute accuracy -- with accuracy increasing to 91% for professionals and 71% for seasonal resource scientists when combining adjacent texture classes. We will also present texture accuracy by soil taxonomic order, compare our results to previous studies of soil texture accuracy, and provide recommendations for reliability of soil texture measurements within national inventory programs.