Earth Partnership for Schools

WOODLAND RESTORATION INTERACTIVE WORKSHOP > HOW TO RESTORE A WOODLAND AT YOUR SCHOOL > STUDY THE SITE > SOIL TEXTURE

Soil is made up of three particle sizes -- sand, silt and clay. Sand is the largest particle; silt is intermediate; and clay is the smallest. Soils have different textures depending upon the proportions of sand, silt or clay particles in the soil. The texture of the soil influences moisture holding capacity of soil, the drainage rate and its ability to hold nutrients. Soils are classified by the way they feel. Sand feels gritty; silt is flour-like; and clay feels smooth when dry or sticky when wet.

 

How Soil Particle Size Affects Drainage

The texture of the soil influences the moisture holding capacity of soil, the drainage rate and the soil's ability to hold nutrients. Coarse, sandy soils drain water quickly and are poor storehouses of nutrients. Plants must be able to tolerate droughty conditions in a sandy soil. In fine-textured clay soils water drains slowly, as a result soil remains wet for long periods, and often root development is hindered. Plants growing in clay soil must be able to tolerate long periods of excessive moisture and low oxygen conditions. The medium texture of silt-sized particles creates a loamy soil that is well drained and holds nutrients. It is ideal for plant growth. Consequently, different soils support different plant species or communities. Determining the soil texture of your restoration plot is one of the informational tools for assessing which community type the soil will sustain.

 

The following soil texture feel test using a key will help you classify your soil. Step-by-step directions are written on the key .

Materials needed:

  • Soil samples from the topsoil and subsoil layers in different areas of the school grounds.
  • Spray bottles of water
  • Paper toweling
  • Key to Soil Texture by Feel