Soil Vulnerability Index

[kevinwolz]

Is the Soil Vulnerability Index still a thing? Has it been added into SSURGO as an interpretation? Many of the links in this doc are dead...

I would love to get my hands on a CONUS 30-m resolution raster of this!

[dylanbeaudette]

This is a good question for Bob Dobos. I'm not sure if SVI is universally appropriate. It is fully implemented in our internal interpretations system. Bob Might be able to generate something for you.

[kevinwolz]

Thanks, I'll check with him and report back.

[brownag]

I am curious which aspects of the SVI-cc you are most interested in. I think SVI rules (as laid out in the doc you linked) can be applied to any map unit, but it was assessed on national/regional basis after masking out non-cropland areas.

For something that has similar intent (using different rules) but is exported in SSURGO already for all components, you might consider checking out mrulename="Fragile Soil Index"

[kevinwolz]

Interesting. Is there somewhere I can find descriptions/metadata on all the interpretations that are in SSURGO? They don't seem to be in the core SSURGO metadata tables.

[brownag]

Good question. It is not part of the SSURGO metadata, but all exported rule descriptions can be found in the "sdvattribute" table.
This information (the attributedescription field) can also be found through the Web Soil Survey Interface

soilDB::SDA_query("SELECT * FROM sdvattribute WHERE attributename = 'Fragile Soil Index'")
#> single result set, returning a data.frame
#>   attributekey      attributename attributetablename attributecolumnname
#> 1         2682 Fragile Soil Index           cointerp           interphrc
#>   attributelogicaldatatype attributefieldsize attributeprecision
#> 1                   String                254                 NA
#>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                attributedescription
#> 1 SOH - Soil Health\n\nSoils can be rated based on their susceptibility to degradation in the "Fragile Soil Index" interpretation.  Fragile soils are those that are most vulnerable to degradation. In other words, they can be easily degradedthey have a low resistance to degradation processes. They tend to be highly susceptible to erosion and can have a low capacity to recover after degradation has occurred (low resilience). Fragile soils are generally characterized by a low content of organic matter, low aggregate stability, and weak soil structure. They are generally located on sloping ground, have sparse plant cover, and tend to be in arid or semiarid regions. The index can be used for conservation and watershed planning to assist in identifying soils and areas highly vulnerable to degradation.\n\nDepending on inherent soil characteristics and the climate, soils can vary from highly resistant, or stable, to vulnerable and extremely sensitive to degradation. Under stress, fragile soils can degrade to a new altered state, which may be less favorable or unfavorable for plant growth and less capable of performing soil functions. To assess the fragility of the soil, indicators of vulnerability to degradation processes are used. They include organic matter, soil structure, rooting depth, vegetative cover, slope, and aridity. \n\nThe organic matter content indicates the capacity of the soil to resist and/or recover from degradation processes. Organic matter improves the soil pore structure, increases water infiltration, and reduces soil compaction and soil erosion. Soil structure indicates the capacity of the soil to resist degradation from accelerated water erosion (by increasing the amount of infiltration). Pore structure is the most important aspect of soil structure as pores provide habitat for organism. Shallow soils are more vulnerable to degradation processes because they have limited rooting depth and have a reduced amount of material from which to form new soil. As erosion removes the upper soil profile, productivity will decline if the subsoil is limiting for crop growth. Vegetative cover is very important as uncovered soil is most vulnerable to the processes of soil erosion, both by wind and water. Slope (a measure of the steepness or the degree of inclination) indicates the degree of vulnerability to erosion and mass movement. Aridity is defined by the shortage of moisture. Lack of water is a main factor limiting biological processes and the ability of the soil to resist and/or recover from degradation.\n\nSoils are placed into interpretive classes based on their index rating, which ranges from 0 to 1. An index rating of 1 is the most fragile, while a rating of zero is the least fragile. Interpretative classes are as follows:\n\nNot Fragile (index rating less than or equal to 0.009)  These soils have a very high potential to resist degradation and be highly resilient. They are highly structured with an organic matter content greater than 5.7%, are nearly level, are deep or very deep, have greater than 85% vegetative cover, and are in a climate that is wet or very wet.\n\nSlightly Fragile (index rating less than 0.009 and less than or equal to 0.209)  These soils have a high potential to resist degradation and be resilient. They are:\n-- Poorly structured to weakly structured soils that have an extremely low to moderate content of organic matter, are very deep, have high vegetative cover, occur on nearly level ground, and are in wet or very wet climates;\n-- Highly structured soils that have a very high content of organic matter, are very shallow to moderately deep, have high vegetative cover, occur on nearly level ground, and are in wet or very wet climates;\n-- Highly structured soils that have a very high content of organic matter, are very deep, have low to moderately high vegetative cover, occur on nearly level ground, and are in wet or very wet climates;\n-- Highly structured soils that have a very high content of organic matter, are very deep, have high vegetative cover; are on slopes greater than 3%, and are in wet or very wet climates; or\n-- Highly structured soils that have a very high content of organic matter, are very deep, have high vegetative cover; occur on nearly level ground, and in semi-dry to mildly wet climates; \n\nModerately Fragile (index rating greater than 0.209 and less than or equal to 0.409)  These soils have a moderate potential to resist degradation and be moderately resilient. They are:\n-- Highly structured soils that have a very high content of organic matter, are very shallow, have high vegetative cover, occur in nearly level to moderately sloping areas, and are in semi-dry climates; \n-- Poorly structured soils that have an extremely low content of organic matter, are deep, have low vegetative cover, occur in nearly level areas, and are in wet or very wet climates; \n-- Poorly structured soils that have an extremely low content of organic matter, occur on gentle to very steep slopes, have high vegetative cover, and are in wet or very wet climates; \n-- Weakly structured soils that have a very low content of organic matter, are deep, occur in nearly level to gently sloping areas, have high vegetative cover, and are in semi-dry climates; or \n-- Weakly structured soils that have a very low content of organic matter, are very shallow to very deep, occur in nearly level to strongly sloping areas, have high vegetative cover, and are in mildly wet climates.\n\nFragile (index rating greater than 0.409 and less than or equal to 0.609)  These soils have a low potential to resist degradation and low resilience. They are:\n-- Well structured soils that have a low content of organic matter, are shallow to very deep, have moderate to moderately high vegetative cover, occur on steep slopes, and are in dry climates; \n-- Well structured soils that have a low content of organic matter, are shallow to very deep, have a low vegetative cover, occur in nearly level to gently sloping areas, and are in dry climates; \n-- Well structured soils that have a low content of organic matter, are deep, have low vegetative cover, occur on nearly level to very steep slopes, and are in a semi-dry climate; \n-- Moderately structured soils that have a very low content of organic matter, are deep, have moderately high vegetative cover, occur on moderately steep to very steep slopes, and are in semi-dry climates; or \n-- Weakly structured soils that have a low content of organic matter, occur on moderately steep to very steep slopes, have low vegetative cover, and are in wet or very wet climates.\n\nVery Fragile (index rating greater than 0.609 and less than or equal to 0.809)  These soils have a very low potential to resist degradation and very low resilience. They are:\n-- Weakly structured soils that have an extremely low content of organic matter, are deep, have low vegetative cover, occur on nearly level to very steep slopes, and are in dry climates; \n-- Weakly structured soils that have an extremely low content of organic matter, are shallow to very deep, have low vegetative cover, occur on nearly level to very steep slopes, and are in very dry climates; or \n-- Poorly structured soils that have an extremely low content of organic matter, are very shallow, have no vegetative cover, occur on steep slopes, and are in mildly wet to wet climates.\n\nExtremely Fragile (index rating greater than 0.809 and less than or equal to 1.0)  These soils can have no potential to resist degradation and no resilience. They are:\n-- Poorly structured soils that have an extremely low content of organic matter, are very shallow, have low vegetative cover, occur on very steep slopes, and are in dry or very dry climates; \n-- Weakly structured soils that have a very low content of organic matter, are nearly level to very deep, have low vegetative cover, occur on very steep slopes, and are in dry climates; or\n-- Very shallow soils on steep slopes.\n\nThe interpretive rating is based on soils that occur in the dominant land use for the map unit component and may not represent soils that occur in site-specific land uses.
#>   attributeuom attributeuomabbrev  attributetype      nasisrulename ruledesign
#> 1         <NA>               <NA> Interpretation Fragile Soil Index          1
#>   notratedphrase mapunitlevelattribflag complevelattribflag
#> 1      Not rated                      0                   1
#>   cmonthlevelattribflag horzlevelattribflag tiebreakdomainname
#> 1                     0                   0               <NA>
#>   tiebreakruleoptionflag tiebreaklowlabel tiebreakhighlabel tiebreakrule
#> 1                      0             <NA>              <NA>            1
#>   resultcolumnname sqlwhereclause primaryconcolname pcclogicaldatatype
#> 1        FragIndex           <NA>              <NA>               <NA>
#>   primaryconstraintlabel secondaryconcolname scclogicaldatatype
#> 1                   <NA>                <NA>               <NA>
#>   secondaryconstraintlabel dqmodeoptionflag depthqualifiermode layerdepthtotop
#> 1                     <NA>                0               <NA>              NA
#>   layerdepthtobottom layerdepthuom monthrangeoptionflag beginningmonth
#> 1                 NA          <NA>                    0           <NA>
#>   endingmonth      horzaggmeth interpnullsaszerooptionflag
#> 1        <NA> Weighted Average                           0
#>   interpnullsaszeroflag nullratingreplacementvalue rptnullratingreplacevalue
#> 1                     0                       <NA>                      <NA>
#>   basicmodeflag maplegendkey maplegendclasses
#> 1             1            5               NA
#>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             maplegendxml
#> 1 <Map_Legend maplegendkey="5">\r\n  <ColorRampType type="2" name="Defined" />\r\n  <Legend_Symbols shapeType="polygon">\r\n    <Styles fillStyle="esriSFSSolid" />\r\n    <Font type="Times New Roman" size="8" red="0" green="0" blue="0" />\r\n    <Line type="outline" width="0.4" red="0" green="0" blue="0" />\r\n  </Legend_Symbols>\r\n  <Legend_Elements transparency="0">\r\n    <Labels value="Extremely fragile" label="Extremely fragile" order="1">\r\n      <Color red="255" green="0" blue="0" />\r\n    </Labels>\r\n    <Labels value="Highly fragile" label="Highly fragile" order="2">\r\n      <Color red="255" green="102" blue="0" />\r\n    </Labels>\r\n    <Labels value="Fragile" label="Fragile" order="3">\r\n      <Color red="255" green="204" blue="0" />\r\n    </Labels>\r\n    <Labels value="Moderately fragile" label="Moderately fragile" order="4">\r\n      <Color red="203" green="255" blue="0" />\r\n    </Labels>\r\n    <Labels value="Slightly fragile" label="Slightly fragile" order="5">\r\n      <Color red="101" green="255" blue="0" />\r\n    </Labels>\r\n    <Labels value="Not fragile" label="Not fragile" order="6">\r\n      <Color red="0" green="255" blue="0" />\r\n    </Labels>\r\n  </Legend_Elements>\r\n</Map_Legend>
#>   nasissiteid             wlupdated      algorithmname componentpercentcutoff
#> 1           1 12/18/2023 6:10:57 PM Dominant Condition                     NA
#>   readytodistribute folderkey effectivelogicaldatatype reviewrequested
#> 1                 1        22                   String               0
#>                                          editnotes
#> 1 10/10/2017 -- Marked "approved" by Robert Dobos.

Currently the only thing soilDB gets from the sdvattribute table is the legend information via soilDB::get_SDV_legend_elements() but there would be room for pulling some of this other contextual information for interpretations in general, either in a new method or an optional argument to get_SDA_interpretation()