Soils are mapped at distinct spatial scales. Soil scientists interpolate, or app

Question

Soils are mapped at distinct spatial scales. Soil scientists interpolate, or approximate, boundaries between soil units (pedons). The resolution of a soil study is known as the order of the soil survey. The scale of each order is given in hectares (ha). One ha is equivalent to an area of 100 m X 100 m (10,000 m2). Soils are classified by identifying soil properties at depth. These are characterized by examining physical (e.g. texture, color) and chemical properties (e.g. SOM) to a depth of <2 meters.

National soils are mapped by soil scientists and provided through STATSGO (State Soil Geographic database) and SSURGO (Soil Survey Geographic database). STATSGO surveys represent a 1:250,000 scale. SSURGO surveys are more detailed with a scale of 1:24,000 or less. Note that STATSGO surveys represent approximately 2.5 soil sample sites per 10 ha, and SSURGO scale represents approximately 2.5 soil sample sites per ha.

Minimum size of delineation

Second order: intensive - general agriculture, urban planning

Third order: extensive - range land, community planning

Fourth order: extensive - for broad land use potential and general land management

Fifth order: very extensive

Based on the table above, what planning activities and management decisions might the STATSGO and SSURGO soil surveys assist with?

STATSGO:

SSURGO:

What activities would require even more detailed sampling than that which is available through SSURGO:

Please Explain and thank you for the help!!

Order of soil survey. Soil Survey Staff. 1993. Soil Survey Manual 18, US Government, Printing Office, Washington, D.C. Order of soil survey

Minimum size of delineation

hectares [ha] First order: very intensive - experimental plots, building sites 1 or less

Second order: intensive - general agriculture, urban planning

0.6 - 4

Third order: extensive - range land, community planning

1.6 - 16

Fourth order: extensive - for broad land use potential and general land management

16 - 252

Fifth order: very extensive

252 - 4000

Explanation / Answer

First order surveys; These surveys are used for those intensive land use activities which require very detailed information in a small area like irrigation, drainage, building sites, experimental sites, citrus or other crops etc. In this the boundaries of the soil are observed throughout their length. Remotely sensed data are also used in boundary delineation of soil. Base map scale is generally lies between 1:1,000-1:10,000. The delineation of the size is usually 1 hectare or less.

Second order surveys: These surveys are used for intensive land uses that need detailed information about the suitability and treatment requirements of soil. This information is used to plan land use activities like urban planning, construction and general agriculture. The scale of the base map is 1:12:000-1:31,680. The minimum size of the delineation is 0.6-4 acres.

Third order surveys: These surveys do not require precise knowledge of small areas and detailed information about the soil. They have a dominantly single use of land and other subordinate uses. eg community planning, range, recreation and forest. The scale of the base map is 1:20,000-1:63,360 and the minimum size of the delineation is 1.6-16 hectares.

Fourth order surveys: They are extensive land uses that need general information about the soil for broad uses like general land management and land use potential. The information obtained can be used for identifying and comparing the area for major land uses, regional land use planning and in identifying areas for detailed investigation and study. Scale of the base map is 1:63,000-1;250,000 and the minimum size of delineation is 16-250 hectares.

Fifth order surveys: The soil information are collected in a very large area. This information is then used to plan regional land use and also choosing areas for more intensive study. Minimum size for delineation is 252-4,000 hectares. Base map scale ranges from 1:250,0000-1:1,000,000 or smaller.

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