Soil is a mixture of mineral matter, organic material, air and water. The mineral portion of soil is made up of particles which vary in size from stones to powder. These particles are called soil separates. The United States Department of Agriculture recognizes three major groups of soil separates: sand (2.0-0.050 mm), silt (0.050-0.002 mm) and clay (<0.002 mm). The relative proportions of these different sized particles determine a soils texture (see figure).

Fine-textured soils contain a high percentage of clay and are very sticky when wet and hard when dry. Heavy soil was term coined long ago when people found clay soils challenging (heavy) to plow. Coarse textured soils have a high percentage of sand and are loose and crumbly. Coarse textured soils are not sticky when wet and are easy to plow; hence the term light soil texture.

Texture is an essential characteristic of soil and affects water holding capacity, drainage properties, root development, and more. Because texture has a significant effect on water movement through soil, it can also affect how pesticides and nutrients work in the soil. High amounts of clay soil particles can also bind up certain pesticides, causing differences in pesticide activity on soils with different soil textures.

There are several methods used for determining soil texture with the most common method being the hydrometer method. In this method, soil particles are dispersed with a reagent and then agitated. After dispersion, the amount of each particle group (sand, silt, clay) is determined by using a hydrometer.

Minimum Sample Size Required: 4-5 cups. This test requires a large amount of soil for an accurate analysis.