Without doubt describing profiles in trenches is the best approach, but it also requires great knowledge and skill that few possess. Soil scientists always progress in their descriptions from the top down. Given that soils actually form from the bottom up, it really makes more sense to progress in this direction. Descriptions are typically recorded on standard forms developed by the U.S. Soil Survey Staff. Recording depths and thicknessess of the horizons is most important.
Trowels are important tools using in describing profiles.
They are used to scrap clean, fresh faces, and to extract from the horizons samples to be analyzed in the lab. Samples from the more conspicuous horizons can then be collected and brought back to the lab for analyses. Once developed, the slide can be used for drawing the profile and the analyzed samples used for finalizing the description.