Soil Technical Note-4 (Revision 1)

Central Great Plains MLRA Region 5
MO5 Soil Technical Note-4 (Revision 1)

October 28, 2008

Subject: SOI – Collection of Transects and Data Population in the National Soil Information System for the Central Great Plains Major Land Resource Area Office Region 5

Purpose. Provide consistency in the collection of transects and in how the transect data is populated in the National Soil Information System (NASIS) within the Central Great Plains Major Land Resource Area (MLRA) Office Region 5 (MO5)

From the National Soil Survey Handbook (NSSH) Section 627.08.e3: “Map units require a minimum of 30 recorded points for each mapunit to document the composition. The points need to be distributed throughout the full extent of the mapunit to account for spatial variability. Depending upon the nature of the mapunit, the points can come from a fixed interval transect, a line transect (points selected to represent line segments related to vegetation, hillslope position, photo tone, etc.) or other techniques to assure composition. This documentation is adequate where the extent of the mapunits are less than 2,000 acres. Where the extent is over 2,000 acres, add an additional 10 recorded points for each 4,000 acres.” The soil data quality specialist (SDQS) will work with project leaders when developing work plans to assist in determining the number of transects required for adequate documentation. The nature of the project and the questions being answered may require fewer transects than suggested in the NSSH. Some projects may require additional documentation.

Most transects should contain 10 points within the mapunit polygon being examined. Small or narrow polygons may not require 10 points to fully document the composition of the polygon. However, polygons that are large (i.e., greater than 160 acres) may require significantly more than 10 points to fully characterize the composition and range in properties. For those mapunits where a 10-point transect is not the best choice, select a number of points that document the mapunit polygon composition and use that number of points consistently throughout the project area for that mapunit.

Polygons selected for transecting should be selected based on how representative they are of the mapunit, work plan goal, and project area. Their size, geology, landform, and geographic distribution should all represent what is being studied. Unless agreed to by the state soil scientist and MO leader, complete pedon descriptions will be taken at each point within the transect.

Transects should be run perpendicular or in a zigzag pattern to the longitudinal orientation of the mapunit polygon; i.e., on a stream floodplain perpendicular to the flow of the stream and deposition (Figure1). On mapunits with complex slope patterns such as dunes, regular intervals may not be practical and all parts of the dune slopes and interdunes should have observations.

Suggested location of transect points

Figure 1. Suggested location of transect points for a long narrow 350 acre floodplain delineation
(Click on image above to download larger version)

Required Transect Information:

Location: Include the published soil survey sheet number and the legal description such as NW1/4 of Section 13, Range 1 East, Township 15 South for the starting point. Additionally, include the Universal Transverse Mercator (UTM) coordinates and the latitude and longitude for each point within the transect and the names of the describers and date described.

Transect ID, Interval and Stop Number: The transect ID will be named as follows: MLRA (106), Year (05), State (KS) County (087), Mapunit symbol (7234) and transect sequence number (03).

Example 1: 10605KS131-7681-03 MLRA is 106, Transect was year 2005, County is Nemaha County, Kansas, Mapunit is Wymore silty clay loam, 1 to 3 percent slopes, 3rd transect in Nemaha County in Kansas on Wymore silty clay loam, 1 to 3 percent slopes.

Interval will be given in meters and stops should be numbered.

Landscape and Landform: Record the geologic formation (if known), slope shape, gradient, aspect, vegetation, drainage class, hillslope position, and geomorphic component for all stops.

Horizon data: Describe all horizons to 2 meters (80 inches) or a restrictive layer. Use Munsell color notation identifying (matrix, redoximorphic features, mottles, coatings, etc). Include texture of horizon and estimates of sand and clay important for class breaks. Record the structure, consistence, effervescence, pH, roots, pores, and boundary class. Record the presence of episaturation or endosaturation and what depth these features were observed. Record any special features needed for classification or interpretation (percent fragments, etc.). Record taxonomic classification, series name if available, and any phase name such as flooding frequency.

Diagnostic Features and Field Measured Properties: Record all diagnostic features and appropriate field measured properties for all pedons of the transect (Table 2).

Populating a Transect in NASIS

To correctly enter a transect in NASIS, begin by establishing a site in the NASIS Site table by opening a new row and entering a User_Site_id and other data for the site. Open a new row in the NASIS Site Observation table and enter the observation date. In the NASIS Site Area Overlap table, populate at a minimum: Area Type of, Non-MLRA Soil Survey Area, County or Parish, MLRA, State or Territory, USGS 7.5 Minute Quadrangles. The following sequence numbers will be used to facilitate populating and editing Map Unit Overlaps.

Site Area Overlaps:

All sites will have site area overlaps with sequence numbers 1 through 5, the rest are optional.

Table 1.

SEQ Area Type
1 Non-MLRA Soil Survey Area
2 County or Parish
4 State or Territory
5 USGS 7.5 Minute Quadrangle
6 Physiographic Division
7 Physiographic Province
8 Physiographic Section
9 State Physiographic Area
10+ Any other

In the NASIS Site Mapunit Overlap table below non-MLRA Soil Survey Area, populate the mapunit overlap. After these fields are populated, save the data. An alternative is to copy and paste an existing row in the NASIS Site table and editing the required fields.

Step two is to establish a record in the NASIS Transect table. Open a new row and enter the User_Transect_id using the naming conventions above. When complete, save the record.

Step three is to establish a new record in the NASIS Pedon table. Enter a User_Pedon_id and establish the link to NASIS site, NASIS Site Observation, and NASIS Transect by entering the appropriate User_Site_id and User_Transect_id or the NASIS record number for those entries in the appropriate fields.

All additional stops in the transect will need another NASIS Site and NASIS Site Observation record completed. This is most easily completed by copy and paste and editing the appropriate field. An entry in the NASIS Pedon table will also need to be made for each stop. Each Pedon will be linked to the existing NASIS Transect. At the end, for a 10-point transect, there will be 10 NASIS Site User_Site_ids, 10 NASIS Site Site Observations, 10 NASIS Pedon User_Pedon_ids, and 1 NASIS Transect User_transect_id.

Each point in the transect should be classified and the classification entered in the classification column. The appropriate series should be entered as well as whether the profile is within the range of characteristics or not. Use a series name that best fits the pedon being described. If the pedon is not within the range of the series, then pedon text notes need to be filled in describing what properties are outside the range of characteristics.

Pedon type column has several choices, MO5 will use the following:

  • Typical pedon: for Official Series Description (OSD) site

  • Modal pedon: local representative pedon for a non-MLRA Soil Survey Area or a mapunit for a MLRA wide update. Make sure there is a pedon text note explaining what area this is modal for.

  • Mapunit inclusion: in the context of a transect documenting the composition of a mapunit, a pedon (series or higher taxon) that is not a named component in the mapunit name.

Example 2: Transecting a Roxbury silt loam, occasionally flooded. Transect stop 3 is a coarse-loamy, mixed, mesic Cumulic Haplustolls. There is currently no series in the project area with this classification. Soil-name-as-sampled would be SND (coarse-loamy Cumulic Haplustolls). Pedon type is mapunit inclusion. In pedon text you describe how this soil is different from Roxbury silt loam; i.e., “This pedon is a non-limiting similar inclusion. The particle size control section has sand content greater than 15 percent and less than 35 percent. Ksat and other soil properties will be similar to Roxbury.” State reasons that will be helpful to others reviewing and using the description in the future.

  • Outside range of series: one or more soil properties are outside range of characteristics require a text note explaining what properties are outside the range of the series used to name the pedon.

Example 3: Transecting a Wakeen silty clay loam and transect stop 10 is only 45 centimeters to chalky limestone instead of 50. Soil-name-as-sampled is Wakeen. The pedon type is Outside Range of series. An appropriate pedon text note would be: “The depth to chalky limestone and shale for this pedon is 45 cm, the series range is 50 to 100 cm.”

  • Within range of series: soil properties are within range of characteristics of series.

Diagnostic features

In some cases you may be entering only the diagnostic features and field measured properties of each soil profile within your transect. The table below identifies those soil properties that need to be recorded. Before populating only the diagnostic features table, ensure that there is agreement between the state soil scientist and the MO leader. Always check with the soil data quality specialist (SDQS) to ensure all the appropriate soil properties are captured.

Table 2.  Diagnostic features and Field measured properties

Propety NASIS Location
Diagnostic Features  
Thickness and type of epipedon NASIS – Pedon – Diagnostic Features
Depth to and type of diagnostic horizons (argillic, cambic, natric, etc.) NASIS – Pedon – Diagnostic Features
Bottom depth of diagnostic horizons (if observed within 2m) NASIS – Pedon – Diagnostic Features
Thickness of diagnostic horizons (if observed within 2m) NASIS – Pedon – Diagnostic Features
Depth to lithic or paralithic contact (if within 2m) NASIS – Pedon – Diagnostic Features
Depth to CaCO3 NASIS – Pedon – Diagnostic Features
Depth to redoximorphic features NASIS – Pedon – Diagnostic Features
Depth to lithologic discontinuity NASIS – Pedon – Diagnostic Features
Any appropriate diagnostic feature from choice list NASIS – Pedon – Diagnostic Feature Choice List
Field Measured Properties  
Estimated percent clay and sand in particle size control section NASIS – Pedon –Field Measured Property
Depth to sand NASIS – Pedon –Field Measured Property
Depth to buried soil NASIS – Pedon –Field Measured Property
Depth to paleosol NASIS – Pedon –Field Measured Property
Depth to auger refusal NASIS – Pedon –Field Measured Property

Some properties, such as depth to water table, could be recorded in several locations. The type and purpose of observation would indicate where the data should be stored. For example, transects done to observe the variability in the depth to water across a mapunit would most appropriately be stored as a field measured property. Observations of variability to depth of water over time at one location would be more appropriately stored in Site - Site Observation – Site Soil Moisture.


State Soil Scientist/MO Leader

DIST: SS (MO5), MO Leaders – TX – CO – ND – MN – AR