Rhode Island Soil Survey - Soil Attribute Join Table

Click here to download this file ( 154 kb Zip file)

Folder Contents:

1. RIsoiljoin.dbf – soil attribute join table.
2. Link_URL.ave – ArcView avenue script to hotlink soil polygons to map unit descriptions via the Internet.
3. A copy of this page in MS Word format.

Background:

The file “RIsoiljoin.dbf” is a dbase IV table that provides additional attribute information for the digital soils data provided from the RI Geographic Information System (RIGIS) website (http://www.edc.uri.edu/rigis/). The table is intended to be joined with the soil attribute table RIGIS provides with the soil coverage. For more information about the contents of this file contact Jim Turenne, Assistant State Soil Scientist, RI NRCS at 401-822-8830 or jim.turenne@ri.usda.gov.

 Instructions – how to use the join table:

1. Unzip the "RIsoiljoin.zip" file contents and extract the 3 files into a folder/directory.
2. Open ArcView GIS and add the RIGIS soil coverage, make the soil theme active, and open the attribute table (click )

Screenshot of step 2 - the RIGIS soil attribute table.

3. In the Table Document View add the RIsoiljoin.dbf table by clicking the “Add” button and navigating to the folder/directory where you unzipped the file.
4. Click on the “Soil_name” field of the RIsoiljoin table (make sure this step comes before step 5).
5. Make the RIGIS soil attribute table active and click on the “Soil-name” field.
6. Click the join button and the contents of the join table should be added to the RIGIS soil attribute table.

Screenshot of steps 3 through 5 – note: you must click the RIsoiljoin field "Soil_name" first, and then click the RIGIS soil attribute table "Soil-name" field before clicking the join table button.

7. Scroll through the RIGIS soil attribute table to see if the additional fields have been added. If they did not or if the RIGIS soil attribute table is blank click the “Table” menu then click the “Remove All Joins” and repeat steps 3-5.
8. To make the attribute table with the joined fields permanent go back to the view menu, make the soil theme active and then select the “Theme” menu – “Convert to Shapefile” select a new file name and destination. If you do not do this the join will be removed when you exit ArcView (unless you save the project).

Explanation of the RISoiljoin.dbf attributes fields:

The join table contains 12 new fields. The following is an explanation of the new fields:

Muname: The soil map unit name used in the published Soil Survey of Rhode Island.

Ord_symb: This field contains the “Ordination Symbol” for woodland suitability which is provided in Table 17 of the published survey. The first part of the ordination symbol, a number, indicates the potential productivity of the soils for important trees. The number 1 indicates very high productivity; 2, high; 3, moderately high; 4, moderate; and 5, low. The second part of the symbol, a letter, indicates the major soil limitation. The letter x indicates stoniness or rockiness; w, excessive water in or on the soil; d, restrictive root dept; s, sandy soil textures; and r, steep slopes. The letter o indicates insignificant limitations.

Soil_name: This is the soil map unit symbol from the published soil survey. This is the common field which joins with the Soil-name field of the RIGIS soil attribute table.

Mukey: This is a numeric field which is needed to use the digital soil data with the NRCS Soil Data Viewer program – visit: http://www.itc.nrcs.usda.gov/ for more information.

Prime:  This field provides the farmland rating of the soil. P, indicates the map unit is Prime Farmland; SI, indicates Statewide Important soil map units; N, indicates the soil is not rated for farmland. Visit: http://www.ri.nrcs.usda.gov/technical/primefarmlands.html for complete information.

Rel_ag: This is a numeric rating from 100 (best) to 0 (worst) of the soil map unit for agricultural production. This number is used for rating the soil for the States Agricultural Land Preservation rating.

Parent_m: This field provides information about the parent material in which the soil formed. The soil parent material is one of the major factors of soil formation used to differentiate many of the soils in the northeast and many interpretations are made based on the type of parent material. The parent material is also used when making soil evaluations for septic systems in RI (see the Isds_class field). NOTE: most upland soils in RI have a thin, 15 to 35 inch eolian or wind blown deposit mantle or cap of sandy loam material overlying glacial deposits. This material is not included in the field except for soil which formed in thick (> 35 inches) deposits of silt loam textured eolian material (loess). The following is a brief description of each type of material listed in the Parent_m field:

• Ablation Till: Also refereed to as "supraglacial meltout till" or "supraglacial flow till". Unsorted, non-stratified material deposited on top or within the upper part of glacial ice and consisting of a heterogeneous mixture of clay to boulder size particles. Ablation till is very variable but tends to be loose and dominantly sandy, but may have lenses of firm loamy material.

• Ablation Till over Bedrock: These map units consist of bedrock-controlled landforms. The soils formed in ablation till (described above) and have ledge or bedrock typically within 6 feet of the surface. These soils are mapped in a complex of shallow, moderately deep, and very deep soils.

• Alluvial Deposits: Material deposited in modern-day floodplains.

• Coastal Dunes and Beaches: Holocene deposits (post glacial) consisting of sandy material transported and deposited by wind and wave activity. These soil and non soil areas occur on beaches and adjacent coastal dunes.

• Fill over Refuse: Active and inactive refuse (landfills, dumps, etc.) areas.

• Fluvial Deposits (glacial outwash):  Stratified deposits of sand and gravel deposited by glacial melt-water streams (also includes fluviodeltaic deposits).

• Human Altered Material: Commonly referred to as fill or human - altered/transported material (anthropogenic soils) - includes a variety of soil and geologic material deposited by human activity.

• Lacustrine Deposits: Well sorted, fine textured sediments deposited on glacial lake bottoms (also some of these soils formed in very thick loess material.

• Lodgement Till (also refereed to as subglacial melt-out, basal, or dense till): Unsorted, non-stratified material deposited within the lower part or beneath glacial ice and consisting of a heterogeneous mixture of clay to boulder size particles. Lodgement till is usually found on drumlins and till ridges. Lodgement till tends to have a higher percentage of silt and clay than ablation till and is usually very dense.

• Loess over Ablation Till: These soils formed in thick (typically greater than 35 inches) silt loam textured loess overlying sandy, ablation till.

• Loess over Fluvial: These soils formed in thick (typically greater than 35 inches) silt loam textured loess overlying fluvial deposits.

• Organic Deposits: Includes both fresh and tidal organic soils formed in more than 16 inches of organic material.

Helrate: This field provides information on the erodibility rating of the soil (used for NRCS ratings). For more information visit: http://www.ri.nrcs.usda.gov/technical/highlyerodible.html

• HEL = Highly erodible soil.

• PHEL = Potential highly erodible soil.

• Not rated.

Cap_cls: This Capability classes and subclasses show, in a general way, the suitability of soils for most kinds of field crops. The soils are classed according to their limitations when they are used for field crops, the risk of damage when they are used, and the way they respond to treatment. The grouping does not take into account major and generally expensive landforming that would change slope, depth, or other characteristics of the soils; does not take into consideration possible but unlikely major reclamation projects; and does not apply to rice, cranberries, horticultural crops, or other crops that require special management. Capability classification is not a substitute for interpretations designed to show suitability and limitations-of groups of soils for rangeland, for forest trees, or for engineering purposes. Visit: http://www.ri.nrcs.usda.gov/technical/capclass.html for more information.

• Class I soils have few limitations that restrict their use.

• Class II soils have moderate limitations that reduce the choice of plants or that require moderate conservation practices.

• Class III soils have severe limitations that reduce the choice of plants, or that require special conservation practices, or both.

• Class IV soils have very severe limitations that reduce the choice of plants, or that require very careful management, or both.

• Class V soils are not likely to erode but have other limitations, impractical to remove, that limit their use.

• Class VI soils have severe limitations that make them generally unsuitable for cultivation.

• Class VII soils have very severe limitations that make them unsuitable for cultivation.

• Class VIII soils and landforms have limitations that nearly preclude their use for commercial crop production.

Capability subclasses are soil groups within one class; they are designated by adding a small letter, e, w, s, or c, to the class numeral, for example, IIe. The letter e shows that the main limitation is risk of erosion unless close-growing plant cover is maintained; w shows that water in or on the soil interferes with plant growth or cultivation (in some soils the wetness can be partly corrected by artificial drainage); s shows that the soil is limited mainly because it is shallow, droughty, or stony; and c, used in only some parts of the United States, shows that the chief limitation is climate that is too cold or too dry.

In class I there are no subclasses because the soils of this class have few limitations (NOTE: The digital data has subclasses added to class I soils due to database constraints, please ignore the subclass on class I soils). Class V contains only the subclasses indicated by w, s, or c because the soils in class V are subject to little or no erosion, though they have other limitations that restrict their use to pasture, rangeland, woodland, wildlife habitat, or recreation.

 Dual Classes: On the digital soil attribute data some Capability classes and subclasses have dual ratings separated by a / for example 7s/8. This is used for soil complex map units where the two soils in the complex have different classes. In map unit complexes where both soils have the same capability class the / is not used.

Isds_class: This field lists the soil class used in the RI Septic System regulations  (http://www.state.ri.us/dem/pubs/regs/regs/water/isdsregs.pdf ). It provides the soil class outlined in section SD 26.01b of the regulation. NOTE: This field is intended to provide general site information and does NOT take place of an onsite investigation.

• Class A -Glacial Lodgement Till: Silt loam to loamy sand texture. Lower profiles tend to have a platy structure and are dense to very dense. Excavation is difficult. High probability of hydraulically restrictive lower layers. Angular rock fragments and occasional cobbles and stones.

• Class B -Glacial Ablation Till: Silt loam to loamy sand throughout the profile. Lower horizons tend to be more sandy. These soils tend to be looser than lodgement tills and typically do not have hydraulically restrictive layers. Lower horizons may be firm. Angular rock fragments and occasional cobbles and stones.

• Class C -Proglacial Outwash Deposit: Also referred to as stratified drift, soil textures range from silt loam to loamy sand (in the upper horizons) to a sandy/ gravely substratum. Stratified layers of water sorted materials may be present. Entire profile tends to be loose and easy to dig except saturated hoizons may be firm or cemented or both. Horizons of rounded rock fragments are common. A silty eolian mantle may also be present.

• Class D -Glacial Ice Contact Deposit: Outwash deposits of well to poorly sorted sands and gravel. Texture can be highly variable over short distances and may include pockets or lenses of silt or silt loam. Stratification may be irregular or absent. Sub-rounded to rounded stones and cobbles are possible.

• Class E -Coastal Dune Deposit: Fine to coarse sands, well sorted, often finely stratified. Little or no silt and clay. Typically no sediment larger than coarse sand. Deposited by wind action or storm overwash.

• Class F -Alluvial Deposits: Material transported and deposited by streams and rivers. Typically well sorted, stratified, fine textured sediment that may have dark layers in the substratum which were at one time surface layers. Subject to seasonal flooding.

• Class G -Eolian Deposits: Wind blown silts deposited after the retreat of the Wisconsin glaciation. Typically brown to dark brown silt ranging in thickness of several inches to several feet. Underlain by outwash, ablation till, or lodgement till.

URL_nrcs: This field contains an internet URL location which links the soil polygon to the map unit description provided in the published soil survey. This field works as the “Hot Link” field for linking the soil polygons to the map unit. For information how to use this feature in ArcView read the instructions below.

Using the Hot Link script:

The "Link_URL.ave" script included in the RIsoiljoin.zip file allows user's to use ArcView "Hot Link" button to link the soil polygons to the map unit descriptions found in the published soil survey via the Internet (Note: map unit descriptions are available online, click here for the link). To use this feature you must have your computer connected to the Internet. The join table has a field called "URL_nrcs" that provides the URL to the map unit description. To use this feature, follow these instructions:

1. Go to the "Documents Type" window and click the "Scripts" button.
2. Click "New" to open a blank script (Script 1).
3. Click the "Load Text File" button and navigate to the Link_URL.ave script to load it (unzip the file and place it in a folder first).
4. Click the "Compile" Script button then the "Run" button. The program will open your explorer window, just ignore this and go back to Arc/View. If you are familiar with using ArcView’s script feature you can change the name of the script to suit your needs, the default script will be called Script1 or some other number depending on how many other scripts you have loaded.
5. Go back to the "View" screen and make the RIGIS Soil theme active. Open the "Theme-Properties" menu and scroll to the "Hot Link" menu. In the "Field" box choose "URL_nrcs", in the "Predefined Action" box choose "Link to User Script", under the "Script" navigate to your Link_URL.ave script (most likely called Script1), click OK.
6. Notice the "Hot Link" button is now active. To use the Hotlink feature click the "Hot Link" button then click on a soil polygon. If everything works your browser should load a map unit description of the soil polygon. If it does not work contact Jim Turenne, Assistant State Soil Scientist, RI NRCS at 401-822-8830 or jim.turenne@ri.usda.gov. NOTE: NRCS web sites are frequently down so if the link does not work but your browser loads try using the feature in a few days.

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