Both the United States and Canada use textural triangles to classify soils. Soil types are named according to the relative proportions of the soil components sand, silt and clay.
Each soil type has distinct proportions of the soil components. This results in each type possessing unique physical characteristics.
One of the key physical characteristics of soil is bulk density. Soil bulk density is defined as the mass of soil particles per volume of space occupied.
Bulk density is relatively easy to calculate. First, soil cores of a given volume are taken in the field. Next, the soil sample is dried in an oven. The dried sample is weighed, and bulk density is calculated by dividing the mass of the oven-dried sample by the volume of the core sample.
Bulk density is measured in g/cm3. The soil types and their corresponding bulk density are as follows: clay 1.25 g/cm³; silty clay 1.21g/cm³; silty clay loam 1.27 g/cm³; clay loam 1.30 g/cm³; sandy clay 1.34 g/cm³; silt loam 1.38 g/cm³; loam 1.43 g/cm³; sandy clay loam 1.40 g/cm³; sandy loam 1.51 g/cm³; loamy sand 1.63 g/cm³; sand 1.69 g/cm³.
Bulk density ranges between 1.25 and 1.69 g/cm³ for pure mineral soils. Soils high in organics and some friable clay may have bulk densities well below 1.0 g/cm³.
- Photo Credit geologic soil image by Stepanov from Fotolia.com
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