Texture and Organic Matter

The relative amounts of sand, silt, and clay are estimated by the feel of the soil in a moist condition. The soils are then classified into three categories: C (coarse textures of sand, loamy sand and sandy loam), M (medium textures of loam and silt loam), and F (fine textures of clay loam, silty clay loam, silty clay and clay.

A 5 gram NCR-13 volumetric scoop of soil is placed into a tared, Kimax beaker, and is dried for 2 hours at 105° Celsius and weighed. The sample is then ashed for 2 hours at 360° Celsius and reweighed. The resulting loss of weight, as a percentage of the dry soil, is the estimate of organic matter content.