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Relating Texture to Hydraulics. Infiltration . Rapid – water enters at > 7.5 cm (3 in) per hour sand, loamy sand, coarse sandy loam with good structure Moderate – water enters at 0.5 - 7.5 cm (0.2 - 3 in) per hour Very fine and fine sandy loam, sandy loam with weak or moderate structure
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Infiltration • Rapid – water enters at > 7.5 cm (3 in) per hour • sand, loamy sand, coarse sandy loam with good structure • Moderate – water enters at 0.5 - 7.5 cm (0.2 - 3 in) per hour • Very fine and fine sandy loam, sandy loam with weak or moderate structure • silt loam, silty clay loam, sandy clay loam, loam, clay loam, or clay with moderate or strong structure • sandy clay with strong structure • Slow – water enters at < 0.5 cm (0.2 in) per hour • Silty clay loam, silty clay, sandy clay and clay with weak structure (commonly 2:1 clay)
Water Holding Capacity Classes • TOTAL for 150 cm (60 in) of soil profile • Very low - <7.5 cm (3 in) of water • Low – 7.5-15 cm (3-6 in) of water • Moderate – 15-22.5 cm (6-9 in) of water • High - >22.5 cm (9 in) of water
0 Loamy sand 30 cm X 0.05 cm/cm = 1.5 cm 30 Clay loam 100 cm X 0.15 cm/cm = 15.0 cm 130 Silt loam 20 cm X 0.2 cm/cm = 4.0 cm 150 1.5 + 15.0 + 4.0 = 20.5 cm
Saturated Hydraulic Conductivity (permeabity) • Rapid (high) – Rates > 12 cm (5 in) per hour • sand, loamy sand, and some sandy loams and loams with strong structure (no redox) • Moderate – Rates 0.5 - 12 cm (0.2 - 5 in) per hour • Textures and conditions not in other classes (few redox features) • Slow – Rates < 0.5 cm (0.2 in) per hour • Clayey textures (clay, sandy clay, silty clay) with weak structure or massive, often 2:1 clay, common or many redox features