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Redoximorphic Features, Wetness Indicators, and Disturbed Soils

Redoximorphic Features, Wetness Indicators, and Disturbed Soils. A play in 3 Acts. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE.

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Redoximorphic Features, Wetness Indicators, and Disturbed Soils

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  1. Redoximorphic Features, Wetness Indicators, and Disturbed Soils A play in 3 Acts NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE

  2. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Acknowledgements USEPA USDA-NRCS Water Resources Research Institute USACOE EPA 319(h) program NCDENR, DEH-OSWW Section The Nature Conservancy Land Owners

  3. Act 1:Redox and Water Tables D. L. Lindbo, Soil Science Dept. North Carolina State University ftp://ftp.soil.ncsu.edu/lindbo/ Ohio Aug 2012 NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE

  4. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Overview • A brief history of water tables • Formation of redoximorphic features • Types of redoximorphic features • Rules for interpretation of redoximorphic features

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

  6. USDA-NRCS Soil Survey Manual and Soil Taxonomy • Determination of water table by morphology is not defined • Drainage classes are defined • Depth to Free Water is defined • Aquic conditions are defined

  7. Agricultural Drainage Classes (ADC) Note: ADC varies State to State

  8. Agricultural Drainage Classes • Vary from state to state • Conditions during growing season • NOT related to Ksat or infiltration

  9. Depth to Free Water or Wetness Class

  10. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Agricultural Drainage Classes vs. Free Water (wetness) Classes

  11. ADC Wetness 0 0 Poorly-drained Very poorly- drained VeryShallow 25 30 Somewhat poorly-drained Shallow 50 60 Moderately Deep Moderately well-drained 90 100 120 Deep Well-drained 150 150 Very Deep 180 200

  12. Aquic Conditions

  13. Aquic Conditions • Redoximorphic Features • Redox concentrations – higher chroma than matrix • Nodules and concretions • Masses • Pore linings • Redox depletions – lower chroma than matrix • Fe depletions • Clay depletions • Reduced matrix – low chroma with color change in 30 minutes after exposure • Reaction to alpha-alpha-dipyridal (AADP)

  14. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Aquic Conditions • Redox concentrations – zone where Fe - Mn oxides have accumulated • Redox depletions – zone where of Fe – Mn oxide have been stripped out • Reduced matrix – low chroma matrix that changes color when exposed to air

  15. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE What are we trying to determine when investigating soil morphology?

  16. These features indicate reduction and saturation has occurred NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Morphology is used to assess the saturation and aeration status of the soil

  17. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Why does this soil look like this?

  18. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Why does this soil look like this? Chemistry

  19. Redox features are like M&Ms =

  20. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Redox Transformations Coating of Fe2O3 Remove Fe Fe2+ Gray Soil Brown Soil Fe3+ 2e- + 6H+ + Fe2O3 2Fe(II) + 3H2O

  21. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE In order to form features: • Anaerobic conditions (reduced and saturated) • Fe and/or Mn (electron acceptor) • Microbes (bugs) present • Carbon (food for the bugs) present • Stagnant or slow moving water

  22. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Redox Concentration (Pore lining) 1. Plant root grows into soil 5. Reduced Fe moves away from decomposing root Reduced Fe oxidizes, soil turnsred 2. Root dies and starts to decompose 3. Water table rises 4. Bacteria continue to decompose root Oxygen reduced Nitrate reduced Fe reduced and removed, soil turnsgray 6. Water drains from root channel 7. Root completely decomposed 8. Water table drops Redox depletion

  23. Time for a Quiz….

  24. Does this soil have a high water table? NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE

  25. The previous profile is located at the edge of this quarry. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE

  26. Is this soil wet? NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE

  27. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Of course not … there’s a drainage ditch – PERMIT IT!

  28. Is the morphology wetness related or is it just leached?

  29. Interpreting Redoximorphic Features – 9 Rules Adapted from Dr. Michael Vepraskas

  30. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Reduction, oxidation and translocation = saturation

  31. The Rules require… Five conditions to be met: • Organic matter is present • Bacteria are active • Soil is saturated (no air filled pores) • Water is stagnant (anaerobic), i.e. not flowing, low dissolved oxygen • Presence of Fe

  32. Interpretation Rule 1 Redox depletions form where roots grow i.e. around root channels or cracks…. Remember all 5 conditions need to be met

  33. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Five conditions met here Not met here

  34. Comments on Rule 1 If depletions occur where roots could not grow, then features may be relict

  35. Interpretation Rule 2 Redox concentrations form where oxygen is present – but the soil may still be saturated

  36. Pore lining formed when oxygen was in root channel and matrix was reduced NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE

  37. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Fast moving water O2 O2 O2 O2 O2 O2

  38. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Slow moving water O2 O2 O2 O2 O2

  39. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Redox concentrations 4 chroma depletion 3 chroma depletion < 2 chroma depletion

  40. Interpretation Rule 3 Redox depletions form when the soil is saturated and reduced

  41. Example of Hydrograph NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE 0 -10 -20 -30 Depth -40 -50 -60 -70 -80 5/6 1/1 4/8 4/22 5/20 1/15 1/29 2/12 2/26 3/11 3/25

  42. Question How do you find the water table?

  43. Determining Depth to Soil Wetness by Code • Find depth to ≤ 2 chroma depletions (by code) • These colors mark the top of the seasonal high water table (SHWT) or wetness condtions

  44. Depth of water table may rise to Depth of seasonal high water table by code

  45. Question Do redox depletions form after soil becomes saturated or after it becomes reduced? Answer: after it becomes reduced

  46. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Critical duration of saturation (days) needed for Fe-reduction to occur

  47. Question If a soil needs 21 d of saturation before it gets reduced, then what is the shortest time a soil can be saturated before redox depletions form? Answer: 21 days

  48. NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE Defining an Equivalent Standard • Can saturation be used in place of morphology? • If, 21 days of saturation corresponds to 2 chroma features and • If, 2 chroma colors are used to determine the water table • Then, the water table can be defined by 21 days of saturation • However, 14 days of saturation has been chosen as the critical duration of saturation

  49. Comments on Rule 3 • Redox depletions form when the soil is saturated and reduced • Water tables rise above depth of redox depletions

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