1. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Relating Texture to Hydraulics

2. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE 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)

3. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Runoff Classes Slope (%)Rapid infiltration Moderate Infiltration Slow Infiltration 0-1Very slow 12Very slowSlow 2-6SlowMedium 6-12MediumRapidVery rapid >12RapidVery rapid

4. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Plant Available Water Holding Capacity cm water/cm soil in. water/in. soil Texture 0.05sands, loamy sands 0.10loamy fine sand, coarse sandy loam, some gravelly textures 0.15sandy loam, sandy clay loam, clay loam, very fine sandy loam, loam, silty clay, sandy clay, clay 0.20silt loam, silty clay loam, silt

5. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE 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

6. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Loamy sand Clay loam Silt loam 0 30 130 150 30 cm X 0.05 cm/cm = 1.5 cm 100 cm X 0.15 cm/cm = 15.0 cm 20 cm X 0.2 cm/cm = 4.0 cm 1.5 + 15.0 + 4.0 = 20.5 cm

7. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE 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

8. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Texture – K sat relationships Soil TextureApprox. K sat Sand, Loamy Sand3-10 in/hr Sandy Loam, Silt Loam1-3 in/hr Clay Loam, Silty Clay Loam0.5-1 in/hr Clay, Sandy Clay0.1-0.5 in/hr Clay (2:1), Silty Clay< 0.1 in/hr

9. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Texture – Bulk Density – Porosity Relaionships TextureBulk Density (g/cc) Porosity (%) Sand1.55+42 Sandy Loam1.40+48 Loam1.2055 Silt Loam1.1556 Clay Loam1.1059 Clay1.0560