The Dirt on Soil

1. The Dirt on Soil

2. What is soil texture? • Soil texture is the fineness or coarseness of a soil. It describes the proportion of three sizes of soil particles. • The textures of soil include: • Sand—large particle • Silt—medium-sized particle • Clay—small particle

3. Soil Particle Size

4. Sand • Sand is the largest particle in the soil. When you rub it, it feels rough. This is because it has sharp edges. Sand does not hold many nutrients.

5. Silt • Silt is a soil particle whose size is between sand and clay. Silt feels smooth and powdery. When wet it feels smooth but not sticky.

6. Clay • Clay is the smallest of particles. Clay is smooth when dry and sticky when wet. Soils high in clay content are called heavy soils. Clay also can hold a lot of nutrients, but doesn't let air and water through it well.

7. Why is soil texture important? Texture is important because it affects: • Water-holding capacity—the ability of a soil to retain water for use by plants • Permeability—the ease with which air and water may pass through the soil • Soil workability—the ease with which soil may be tilled and the timing of working the soil after a rain • Ability of plants to grow—some root crops like carrots and onions will have difficulty growing in a fine-textured soil

8. References Soil Background Picture http://foxsilver.deviantart.com/art/Soil-and-Grass-114597279?qj=15&q=sort%3Atime+favby%3Acc5zt&qo=3666&offset=10 Particle Pictures/Information http://urbanext.illinois.edu/gpe/case2/c2facts2.html http://qldgeotechnical.com.au/main/page_soil_info_soil_types.html Sand Picture http://notesmaster.com/notes/syllabus/viewer/1575-types-of-soils Silt Picture http://westhooksandandgravel.com/BlueClayPondSiltCrushedItem4.html Clay Picture http://soils.usda.gov/technical/classification/orders/ultisols.html