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Map Unit Design Concepts Part 2

Map Unit Design Concepts Part 2. Where we left off:. Once we create or evaluate the map unit delineations and document the map unit components, we then analyze map unit documentation to determine: 1. kind of map unit 2. kind of component 3. similar and dissimilar components

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Map Unit Design Concepts Part 2

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  1. Map Unit Design ConceptsPart 2

  2. Where we left off: • Once we create or evaluate the map unit delineations and document the map unit components, we then analyze map unit documentation to determine: 1. kind of map unit 2. kind of component 3. similar and dissimilar components 4. the role of Soil Taxonomy

  3. A collection of areas defined and named the same in terms of their soil components or miscellaneous areas or both What is a map unit?

  4. Kinds of Map Units • Consociation • Complex • Association • Undifferentiated group • Line segment • Ecological unit

  5. What is a component? • It is a collection of pedons (polypedons) that are members of a given taxon or miscellaneous area.

  6. Kinds of Components • Series • Taxa above series • Taxadjunct • Miscellaneous area

  7. Similar and Dissimilar Components

  8. Similar - Dissimilar Modeling MO14 Model

  9. Similar Dissimilar Modeling • Promotes consistency • Removes subjectivity • Documents decisions • All of the above results in enhanced data joins

  10. A Mathematical Model for Determining Similar and Contrasting Inclusions for Map Unit Descriptions M. L. Norfleet and R. T. Eppinette Soil Scientists, NRCS, SC Soil Survey Horizons Spring 1993 issue

  11. Numerical Values for Soil Properties Difference of 2 or more in any single category=Dissimilar Total difference of 3 or more in all categories=Dissimilar

  12. Guide to Determining Similar and Dissimilar Soils

  13. Adjoining property classes Adjoining classes arbitrarily set as not dissimilar

  14. Adjoining property classes Adjoining classes arbitrarily set as dissimilar

  15. Background • Interps are property driven • Hence, model is driven by soil properties

  16. Variety of models • Models may vary from region to region • Models may vary from land use to land use within same region • Cropland versus engineering • NRCS versus NF

  17. Each region/survey area • Determines what to apply model to as far as interps • Selects important properties • Assigns class values to each property

  18. Issues • More than one model in a region and/or survey area ? • Engineering • Cropland

  19. Issues • Where to stop one model and start the other on the landscape • Will increase legend size

  20. Review • Concept requires consensus within a region • Gets us away from subjective decisions • Provides consistent decisions based on soil properties • Enhances consistent joining between surveys

  21. Review • Can be applied anywhere • Can be applied to any order • Remember that it is only a tool to name soil map units • We can still address any and all components in NASIS as decided by you and/or your MO and/or customers

  22. The Role of Soil Taxonomy

  23. The Role of Soil Taxonomy • It provides a NCSS standard of international scope – facilitates consistent communication of soil information

  24. The Role of Soil Taxonomy • It provides a NCSS standard of international scope – facilitates consistent communication of soil information • It is conceptual in nature

  25. Guy Smith, from the onset of Soil Taxonomy, recognized the conceptual nature of taxonomic units versus the “real” natural bodies of variation defined as the map unit. Reference: Guy Smith Discusses Soil Taxonomy, reprint from Soil Survey Horizons, 1977.

  26. The Role of Soil Taxonomy • It provides a NCSS standard of international scope – facilitates consistent communication of soil information • It is conceptual in nature • It provides a very useful standardized classification key with a dynamic characteristic to handle the potential unknown

  27. The Role of Soil Taxonomy • It provides a NCSS standard of international scope – facilitates consistent communication of soil information • It is conceptual in nature • It provides a very useful standardized classification key with a dynamic characteristic to handle the potential unknown • It provides a basis from which to build a soil formation model

  28. The Role of Soil Taxonomy • It provides a NCSS standard of international scope – facilitates consistent communication of soil information • It is conceptual in nature • It provides a very useful standardized classification key with a dynamic characteristic to handle the potential unknown • It provides a basis from which to build a soil formation model • It requires independent and practical thought when applied to delineating map units and to defining and correlating components

  29. Soil Taxonomy – A Historic Grounding(from ‘Guy D. Smith Discusses Soil Taxonomy’, reprint from Soil Survey Horizons) • “There is a distinction between the taxonomic unit, which portrays the conceptual, and the mapping unit which portrays or attempts, at least, to portray the real bodies of soil that we find in the field.”

  30. Soil Taxonomy – A Historic Grounding, cont’d • “The limits of the polypedon, which is the taxonomic unit, are controlled by natural factors of soil formation.” • “Natural bodies that match the definition of polypedons are controlled by another set of factors which include both the scale of the map that we are making and the purposes for which we are making the map.”

  31. Soil Taxonomy – A Historic Grounding, cont’d • “The problem arises when we attempt to use the same name for a taxonomic unit and a cartographic unit.” • “Polypedon concepts require the map maker to study the mapping unit and the kinds of soil that it includes rather carefully so that something is known about the actual variability of soil properties within the area that is to be included within a single map delineation.”

  32. Soil Taxonomy – A Historic Grounding, cont’d • “The soil scientist must decide on a name for the mapping delineation representing the kinds of variability documented and how these effect the use of the soil for the probable forseeable uses.” • “Soil differences that change the classification of the mapping unit from one Order to another, perhaps from Inceptisol to Mollisol because of a difference of a few centimeters in thickness of the epipedon, changing it from ochric to mollic, may not be relevant to the use of the soil.”

  33. Soil Taxonomy – A Historic Grounding, cont’d • “If both soils with and without the mollic epipedon have exactly the same family modifiers in the family name, it is unlikely that this difference is going to be relevant to any particular use.” • “Therefore, in selecting the name, the map maker may select whichever of these taxa are more extensive in the field.” • “The user of the map is not particularly concerned with the taxonomy; the concern rests with the interpretations that the map maker furnishes.”

  34. Soil Taxonomy – A Historic Grounding, cont’d • “It is important that the map maker does not mislead the user of the map.” • “If there are differences within the kinds of soil that are included with the map delineation that are significant to the prospective soil uses, the map maker, in selecting the name, must then consider the alternatives for names to reflect the presence of soils that behave in a significantly different manner.”

  35. Soil Taxonomy – A Historic Grounding, cont’d • “If percentages are very small, the map maker may choose to neglect these in naming the unit or, to indicate the locations of the contrasting soils with spot symbols.” • “Or, if the variability is such that it affects management of the entire map unit, the map maker will probably choose to name the map unit as a complex or as an association so that the map user is warned that there are going to be specific problems in the use of that particular mapping unit.”

  36. The Role of Soil Taxonomyin Map Unit Design • Appears that it has not changed since the inception of Soil Taxonomy • It is a conceptual system of soil classification applied to “real” soil landscapes • It is a standardized tool we can use to help define and name map unit delineations for the ultimate purpose of providing defined soil interpretations for users • In addition, because of the nature of Soil Taxonomy and how it is defined, it provides a snapshot of soil formation

  37. Soil Taxonomy ConceptsvsReal World • Series A Series Range in Characteristics Lo-skel, mixed, super, mesic Lithic Argixerolls Mollic – 5 to 7 inches PSCS – 23 to 33% clay, 35 to 75% rock frags Lithic contact – 4 to 12 inches (basalt) pH – neutral to slightly alkaline MAST – 47 to 54 degrees F. Aridic A horizon – value, 3-5 D, M; chroma 2-4 D, M Bt horizon – value, 3-5 D, M; chroma 2-4 D, M; texture L, CL

  38. Series A cont’d. Geographic Setting MLRA – 8 Slope – 0 to 65% Elevation – 1,000 to 4,000 feet Landscape – ridgetops, benches, hillslopes, scablands Origin – loess and residuum from basalt MAP – 9 to 15 inches MAAT – 45 to 52 degrees F. FFP – 110 to 180 days Use Rangeland; sandberg/stiff sagebrush

  39. Series B – Series Range in Characteristics Lo-skel, mixed, super, mesic Lithic Haploxerolls Mollic – 5 to 10 inches PSCS – >18% clay, 50 to 90% rock frags Lithic contact – 4 to 10inches (basalt) pH – slightly acid to slightly alkaline MAST – 47 to 55 degrees F. Aridic A horizon – value, 4-5 D, 2-3 M; chroma 2-4 D, 2-3 M Bw horizon – value, 4-5 D, 2-3 D; chroma, 2-3 M (upper part) 3-4 M (lower part below 6 “); texture L, CL, SIL; may have clay films on rock frags in some pedons

  40. Series B cont’d. Geographic Setting MLRA – 8 Slope – 0 to 90% Landscape – ridgetops, hillslopes, benches, scablands Elevation – 540 to 4,800 feet Origin – loess and residuum from basalt MAP – 9 to 16 inches MAAT – 45 to 53 degrees F. FFP – 110 to 180 days Use Rangeland; sandberg/stiff sagebrush

  41. Compare soil A and soil B Series Range in Characteristics A - Lo-skel, mixed, super, mesic Lithic Argixerolls B - Lo-skel, mixed, super, mesic Lithic Haploxerolls A - Mollic – 5 to 7 inches B - Mollic – 5 to 10 inches A - PSCS – 23-33% clay, 35 to 75% rock frags B - PSCS – >18% clay, 50 to 90% rock frags A - Lithic contact – 4 to 12 inches (basalt) B - Lithic contact – 4 to 10 inches (basalt) A - pH – neutral to slightly alkaline B - pH – slightly acid to slightly alkaline A - MAST – 47 to 54 degrees F. B - MAST – 47 to 55 degrees F. A - Aridic B - Aridic A horizon – overlapping value and chroma soil A and B B horizon – overlapping value and chroma soil A and B A – Bt horizon described as concept; texture L, CL B – Bw horizon with clay films on rock frags described as concept; texture L, CL, SIL

  42. Compare soil A and soil B Geographic Setting A - MLRA – 8 B - MLRA – 8 A - Slope – 0 to 65% B - Slope – 0 to 90% A - Elevation – 1,000 to 4,000 feet B - Elevation – 540 to 4,800 feet A – ridgetops, benches, hillslopes, scablands B - ridgetops, benches, hillslopes, scablands A - Origin – loess and residuum from basalt B - Origin – loess and residuum from basalt A - MAP – 9 to 15 inches B - MAP – 9 to 16 inches A - MAAT – 45 to 52 degrees F. B - MAAT – 45 to 53 degrees F. A - FFP – 110 to 180 days B - FFP – 110 to 180 days Use A - Rangeland; sandberg/stiff sagebrush B - Rangeland; sandberg/stiff sagebrush

  43. Series, Setting, & Use Differentia • Different taxonomic soil great group • Same MLRA • Same or overlapping soil properties • Same or overlapping geographic setting • Same use and mgt.

  44. Correlation Decision • If map unit documentation resulted in both of these concepts, what would your decision be?

  45. These soils are similar, choose the most extensive and name based on complete map unit delineation concept. • These are real series: Series A = Argabak and series B = Bakeoven. • Both series mapped extensively. Argabak and Bakeoven in WA; Bakeoven in OR • On a bigger geographic picture, from the MO perspective…a reasonable question would be, “are these two series concepts really one concept?” • This appears to be a potential MLRA update issue.

  46. Examples of Soil TaxonomyMap Unit Challenges • Jory and Olympic • Same taxonomic classification: Fine, mixed, active, mesic Xeric Palehumults • Same MLRA: 2 • Soil properties: identical except for ochric vs. umbric epipedon • Geographic setting: Jory – east flank foothills of Coast Range Mts.and west flank foothills of Cascade Mts. in Oregon Olympic - east flank foothills of Coast Range Mts. in Washington • Use and Management: Jory – forestry, Christmas trees, orchards, crops Olympic – forestry, Christmas trees, crops • Would a legend have both of these soils? • Is this an MLRA update issue?

  47. Examples of Soil TaxonomyMap Unit Challenges • Klicker and Larabee • Same taxonomic classification: Loamy-skel, isotic, frigid Vitrandic Argixerolls • Same MLRA: 43C and 43B • Soil properties: similar or overlapping except for Alox + 1/2Feox and • consecutive days dry (0.4-0.8% and 60-75 days vs. • 0.8-1.5% and 45 to 60 days) • Geographic setting: Klicker – mountains, plateaus, benches; MAP – 15-40 “ Larabee – backslopes, shoulders, plateaus; MAP – 24-30 • Use and Management: Klicker – forestry (P-pine, D-fir, c-snowberry, oceanspray) (domin. PIPO or PSME, w/ PIPO phase) Larabee – forestry (D-fir, G-fir, P-pine, elk sedge, white spirea, c- snowberry) (domin. PSME or ABGR) • Would a legend have both of these soils? • Is this an MLRA update issue?

  48. Examples of Soil TaxonomyMap Unit Challenges • Haplo vs. Dystroxerepts • Mixed vs. Isotic Mineralogy • Vitrandic vs. Typic

  49. Map Unit Design & Analysis • Determine composition of delineation(s) based on documentation, evaluation, and analysis “Polypedon concepts require the map maker to study the mapping unit and the kinds of soil that it includes rather carefully so that something is known about the actual variability of soil properties within the area that is to be included within a single map delineation.” • Determine similar vs. dissimilar components based on model • Select modal concept(s) based on composition decision • Classify modal concept(s) based on Soil Taxonomy • Make correlation decisions based on series competitors, assistance from other SS, MO, etc. (new series, existing series, taxadjunct) • Name the map unit based on current NCSS standards “The soil scientist must decide on a name for the mapping delineation representing the kinds of variability documented and how these effect the use of the soil for the probable forseeable uses.”

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