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Friday, September 12, 2014

Sand Bracketing 101

Estimating sand percentages in the field using the textural triangle and "bracketing" approach:

1. You all know that clay percentages are usually the most consistently estimatable textural property by feel in the field. It is not unheard of to consistently estimate clay percentages to within 4-6% of mechanical analysis if you are well calibrated and know the soils of your region.



2. Your clay percentages should consist of a "bracket" (4-6% range that you think is reasonable). For example, I might bracket my clay % in a certain sample to 25-30%.


3. Then you can use the width of textural class and clay bracket to determine your sand bracket (you can do the same with silt if desired) . 


Now, to do this without the triangle in front of you means you REALLY would need to be at one with it!