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Oak Hill Case

Oak Hill Case. Soil Chemical Problems. Water Deficits. Ion Toxicities. SALT -RELATED PROBLEMS. Ion Imbalances. Soil Permeability. Water Deficits. Ion Toxicities. SALT -RELATED PROBLEMS. Ion Imbalances. Soil Permeability.

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Oak Hill Case

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  1. Oak Hill Case Soil Chemical Problems

  2. Water Deficits Ion Toxicities SALT -RELATED PROBLEMS Ion Imbalances Soil Permeability

  3. Water Deficits Ion Toxicities SALT -RELATED PROBLEMS Ion Imbalances Soil Permeability

  4. Water deficits reflect salinity problems from salt concentrations Soil permeability reflects sodicity problemsfrom sodium concentrations

  5. Salinity A measure of the salt concentration of water

  6. Common Salt Ions Ca2+ K+ NO3- HCO3- Mg2+ Cl- Na+ CO32- SO42-

  7. Salinity Measurement • Measured as the electrical conductivity of water (ECw) • Expressed as decisiemens per meter (dS/m); formerly as mmhos/cm.

  8. sw vs ECe

  9. Transpiration High salt concentration

  10. ¯ stomatal opening ¯ cell-turgor pressure ¯ cytokinin synthesis ­ leaf wilting ¯ cell-turgor extensibility ¯ transpirational cooling ¯ photosynthesis ­ respiration ­ DESICCATION ¯ GROWTH Salt-Induced Water Deficits ¯ WATER UPTAKE

  11. C1-S4 C2-S4 C3-S4 C1-S3 Sodium C4-S4 C2-S3 Hazard C1-S2 C3-S3 C2-S2 C4-S3 C3-S2 C1-S1 C4-S2 C2-S1 C3-S1 C4-S1 0.25 0.75 2.25 EC(dS/m) 1 2 3 4 at 25 C Class Salinity Hazard o

  12. Sodicity A measure of the sodium [Na+] concentration in relation to the calcium [Ca+2] and magnesium [Mg+2] concentrations of water

  13. Sodicity Measurement • Measured as the sodium absorption ratio of water (SARw) • Expressed as the ratio: Na+/ ([Ca+2 + Mg+2]/2) 1/2 • Where the concentration of each ion is expressed in milliequivalents per liter (meq/L)

  14. Problem With a water-quality report providing sodium, calcium, and magnesium concentrations as 76, 146, and 39 mg/L, how do we express these in meq/L?

  15. Atomic Weights

  16. Atomic Weights

  17. Sodium: 76 mg/L / 23 mg/meq = 3.3 meq/L Calcium: 146 mg/L / 20 mg/meq = 7.3 meq/L Magnesium: 39 mg/L / 12 mg/meq = 3.2 meq/L SARW = 3.3/ ([7.3+3.2]/2) 1/2 = 3.3/(5.25) 1/2 = 3.3/2.29 = 1.44

  18. C1-S4 C2-S4 C3-S4 C1-S3 Sodium C4-S4 C2-S3 Hazard C1-S2 C3-S3 C2-S2 C4-S3 C3-S2 C1-S1 C4-S2 C2-S1 C3-S1 C4-S1 0.25 0.75 2.25 EC(dS/m) 1 2 3 4 at 25 C Class Salinity Hazard o

  19. Problem With a water-quality report providing a bicarbonate concentration of 366 mg/L, how do we express this in meq/L and what is its significance?

  20. Residual Sodium Carbonate RSC = [CO3-2] + [HCO3-] - [Ca+2] + [Mg+2] Where [ ] = ion concentrations in milliequivalents per liter (meq/L)

  21. Atomic Weights

  22. Residual Sodium Carbonate RSC = [0] + [6.0] - [7.3] - [3.2] = -4.5

  23. RSC Hazard

  24. Amendments Required to Neutralize Residual Carbonates RSC * 234 lbs gypsum/acre-foot RSC * 133 lbs sulfuric acid/acre-foot

  25. soil aggregate

  26. H H H O O H + H H Na O O H H H O O H H H

  27. Na Effects on Soil Permeability ¯ O2 status ­hardness water ¯ infiltration ¯ drainage ¯ percolation ­ retention aeration strength Soil Porosity ¯ macroporosity ¯ pore continuity

  28. Salt-Affected Soils

  29. Soil Types

  30. Soil Salinity Hazard

  31. Soil Sodium Hazard

  32. Turfgrass Salinity Tolerance

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