Textural Classification of Soils¹ 

Soil texture refers to the relative proportions of sand, silt, and clay particles that make up the soil mass. The chart below shows the percentage of these soil fractions in the basic textural grades. 

Three classifications — sandy loam, loam, and silt loam — are common surface soils; they also may occur as subsoils. The rest of the classifications are subsoils.

¹ Timber Management Field Book. USDA-Forest Service Northeastern Area NA-MR-7.

 Soil Composition

Soil provides both the structural medium in which all plants grow and also supplies most of the water and nutrients that are critical to their survival. Thus soil is a unique medium that is difficult to envision in its undisturbed state. This article gives a unique understanding of this complex, living medium as well as it's interaction with plants and water.

Click Here for Article on Soil Composition and Interactions between Soils and Plants

by Richard C Schultz 
Professor of Natural Resource Ecology and Management, Iowa State University