Particle Size Distribution

The total of the percentages, by weight, of soil particles of clay, sand and silt within a soil sample, with the different proportions of each soil particle size being quantified and contributing to the whole, which adds up to 100%. The particle size distribution is essentially the soil texture with the added accuracy of a breakdown of particle size proportions being given.

An example, which is a sandy loam, is:
• 60% sand (2mm ¯ 0.0625mm)
• 25% silt (0.0625mm ¯ 0.002mm)
• 15% clay (<0.002mm).

For turfgrass situations the sand classification is normally identified using the US sand scale, so might see the 60% split into:
• Very Coarse Sand (2 to 1mm): 2%
• Coarse Sand (1 to 0.5mm): 15%
• Medium Sand (0.5 to 0.25mm): 30%
• Fine Sand (0.25 to 0.125mm): 10%
• Very Fine Sand (0.125 to 0.0625mm): 3%