Soil science students and others are often asked to estimate soil texture. The problem is how to evaluate the estimates. The instructor may give full credit for the correct texture class and partial credit for adjoining classes. This works well if the sample is near the center of a class, but not so well if it is near a class boundary. We developed a computer program based on a spreadsheet that quantitatively evaluates the estimates. If the estimate coincides exactly with laboratory results, the score is 100%. If the estimate and laboratory results are as far apart as possible, at opposite corners of the texture triangle, the score is zero. Other scores are based on the distance between points representing the estimate and the actual on a texture triangle in relation to the length of one side of the triangle. Indiana Registered Soil Scientists must periodically compare their field evaluation of soil morphology and landscapes with that of their peers or with laboratory analyses. They estimate the particle size distribution of 10 samples, and the results are graded using this program. Typical scores are in the low to mid eighties.
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