http://www.sdgs.usd.edu/geologyofsd/geosd.html

Soil texture Defined the proportion of particle sizes in the soil mineral component - particle size is related to pore-size distribution . larger pore sizes occur with larger size particles Section VI

------------------- 2 mm Particle Size Class Name Diameter(m) Limit of particle diameter ------------------- 2 mm -------------------- .05mm -------------------- .002 mm Section VI

Soil Particle Relative Size Diameter Shape (mm) Shape grain elevator complex (100’) sand 0.05 – 2.0 angular silt 0.002 – 0.05 basketball (12”) angular clay <0.002 flat Stamp (1”)

1). using the textural triangle (TT) lab analysis determines mineral particle size analysis TT determines textural classes of soils . similar physical properties

General Textural Categories Fine Coarse Medium

Location of General Textural Categories mixed Fine/ Medium/ Medium Fine mixed http://www.sdgs.usd.edu/geologyofsd/geosd.html

a). characteristics of fine-textural class (e.g.: clay, clay loam, silty clay loam) - High nutrient and water holding capacities . 2.0-3.5” water/foot soil - Poor drainage - Poor root penetration - Prolonged Spring warm- up period

b). characteristics of coarse-textural class (e.g.: sand, loamy sand, sandy loam ) - Low water holding capacity . 0.6- 1.3” water/foot soil - Excessive drainage - Low in nutrients

2). Using the “Feel Method a). Method - soil sample is wetted and worked with fingers Squeeze soil between your fingers and thumb Extrude a ribbon of soil ¼” thick Place moist soil sample in hand palm

b). “Feel” Method Approximations Fine-Textured Soils: - form long, shiny, sticky, pliable ribbons - dry clods are very hard Medium-Textured Soils: - ribbons not strong, not gritty - wet soils feel floury when dry Coarse-Textured Soils: - no ribbons, gritty feel - some mineral particles are visible