ESC/BIO 334-SOIL SCIENCE

     SOILS AND LANDUSE

Clip Art: Soil Quality Institute

You need to know:

1. Know the contents of a soil survey manual, be able to quickly locate specific information, and know its limitations.
2. The definitions of benchmark soils, prime farmland, and unique farmland
3. The application of the Land Capability Classification (LCC) and subclass
4. Approaches available to manage land use

Misconceptions

I. Know the contents of a soil survey manual and to be able to quickly locate specific information.

a. polypedon:  a group of                               pedons.  Pedons are a three-dimensional body of soil large enough to permit the study of horizon shapes and relations, its area ranges from 1 m² to 10 m².  Soil series attempt to show polypedons.   Where the typical or representative pedon occurs for a particular soil series, it is the termed the                                  or typical pedon.  The type locality is found in the "Classification of Soils" section of the soil survey manual.  In the case of the Saginaw County manual, the typical pedon in discussed in the second or third paragraph of each soil classification description. On what map photo sheet is typical pedon found? 

b.                                    can be assigned to a series, association, or complex that are assigned a number when appearing on a map.  What is the 
map unit of the Tappan-Londo Association?                   Where is the soil association with a map unit of 12 located? along the                                                            

What is the dominant soil association mapping unit in Sec. 1-6 T10N, R6E ?                    

c. soil series (consociation)--The most specific and lowest  category of U.S. system of soil taxonomy;   Soil series are used to name dominant polypedons represented on detailed soil maps.  Up to 25% of the series could include similar and dissimilar soils.  These soils would be called an                                           No more than 10% of a soil series should be represented by a single dissimilar soil.  Given this limitation, Why is field work necessary when using the soil survey manual?

What is the soil series located NE1/4, NE1/4, Sec. 2, T13 N, R3E?                                  

d. soil association--two or more series that occur in a                                                                        While geographically associated they may or may not have similar properties.  A certain soil association has  a mapping unit number of 9.  How suited is this soil association for building ?                                               

e.                                   -two or more series that occur together in such an intricate pattern that it is not practical to map the series separately.  Using the "Index to Map Units" p. iv, how many complexes exist for Saginaw County?                          

2.  How physical and cultural features are symbolized on soil map photos
Turn to the "Conventional and Special Symbols Legend" found opposite the "Index to Map Sheets" centerfold.  In the space below, sketch the symbols associated with the following features:

3.  Explain the limitations of soil surveys and importance of onsite evaluation.
Information garnered in a soil survey is                                data.  It is based on tests performed on the type locality associated with each soil series.  The inferred properties of the type locality are extended to the map unit.  Soil properties will diverge from this idealized description as you sample further and further away from the type locality.  

Due to time and cost constraints soil surveys are limited by at least four factors.

a.  scale limitations--great differences in soils can occur with short distances, particularly in                         terrains; although these maps are considered large scale, significant localized variation will occur due to the effects of varying parent material, vegetation, and human intervention.  

b.  recency--subdivisions, a field undergoing succession, or a succession of dry years may occur after a pedon for a type locality was sampled.   What implications will this have on the type of soil characteristics?  

c.  variations in polygon boundaries between                                             

d.  Miscellaneous Limitations:  

-----value ranges         vs.         exact values

Contrast how pH, organic matter, and bulk density are reported and K values are reported  in tables

Implications on accuracy or data entry into a GIS? 

-----dated values         vs.        recent values

Find the page numbers where the following information is located:

6.  Identify soil characteristics that are compatible with a given land use.

The following soil characteristics are listed in the soil survey manual under "Physical and Chemical Properties"  and "Soil and Water Features."  Find the page number where each of these variables are located 

II. The definitions of benchmark soils, prime farmland, and unique farmland

a. prime farmland--soils that consistently produce high yields of food or forage with regular management
b. wetland--A transitional area between aquatic and terrestrial ecosystems that is inundated or saturated for long enough 
periods to produce hydric soils and support hydrophytic vegetation. See also bay, bog, fen, marsh, pocosin, swamp, and tidal flats.

III. The application of the Land Capability Classification (LCC) and subclass

The U.S. Natural Resource Conservation classifies all land into one of eight land capability classifications
based on fertility, the risk of land damage, or the difficulty of land use.  These categories are listed below:

Class I - Soils that have few limitations restricting their use.
Class II - Soils that have some limitations, reducing the choice of plants or requiring moderate conservation practices.
Class III - Soils that have severe limitations that reduce the choice of plants or require special conservation practices, or both.
Class IV - Soils that have very severe limitations that restrict the choice of plants, require very careful management or both.

Land generally not suitable for cultivation (without major treatment).

Class V - Soils that have little or no erosion hazard, but that have other limitations, impractical to remove, that limit their use largely to pasture, range, woodland, or wildlife food and cover.
Class VI - Soils that have severe limitations that make them generally unsuited for cultivation and limit their use largely to pasture or range, woodland, or wildlife food and cover.
Class VII - Soils that have very severe limitations that make them unsuited to cultivation and that restricts their use largely to grazing, woodland, or wildlife.
Class VIII - Soils and landforms that preclude their use for commercial plant production and restrict their use to recreation, wildlife, water supply, or aesthetic purposes.

land capability subclass -  The four kinds of limitations recognized at the subclass level are: risks of erosion, designated by the symbol (e); wetness, drainage, or overflow (w); other root zone limitations (s); and climatic limitations (c). The subclass provides information about the degree and kind of limitation.  Capability Class I has no subclasses.

IV. Approaches available to manage landuse

eminent domain

preferential tax assessments

buying development rights

Web Resources to Supplement these Objectives

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