**Amendment 4 (September 1998)**

The following changes have been made to the National Soil Survey
Handbook in the web version for downloading and in the on-line
hypertexted version. The NRCS-SOI-37A will be reprinted and distributed
separately.

**Specific changes:**

**1. Exhibit 602-1**

-   Change in all parts: Director of Soils to ***Director of Soil Survey
    Division***

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-   Article III - Add the following:

-   ***Section 2.1.4 Soil scientists from each of the six NRCS regional
    offices are included as\
    members.***

-   Article VI - Change:

-   ***Section 1.1.4 Four Agriculture Experiment Station Soil Survey
    Leaders, one from each\
    respective Regional Conference. This normally is the state
    representative\
    that will be chair or vice chair of the next Regional Conference.***

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-   Article VI - Add:

-   ***Section 1.1.7 A representative of the 1890 College from the
    vicinity of the next\
    conference recommended by the Conference Chair.***

-   ***Section 1.1.8 A representative of the Tribal College from the
    vicinity of the next\
    conference recommended by the Conference Chair.***

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-   Article VI - Change Section 4.0 to be:

-   ***Section 4.0 The Steering Committee shall:***

-   Article VI - Delete:

-   ***Section 4.1***

**2. Exhibit 606-1 and Exhibit 606-2**

-   Last paragraph before signatures, replace with the following
    paragraph:

> ***Activities conducted under this Memorandum of Understanding will be
> in compliance with the nondiscrimination provisions as contained in
> Titles VI and VII of the Civil Rights Act of 1964, as amended, the
> Civil Rights Restoration Act of 1987 (Public Law 100-259) and other
> nondiscrimination statutes, namely Section 504 of the Rehabilitation
> Act of 1973, Title IX of the Education Amendments of 1972, the Age
> Discrimination Act of 1975, and in accordance with regulations of the
> Secretary of Agriculture (7CFR-15, Subparts A and B) which provide
> that no person in the United States shall on the grounds of race,
> color, national origin, age, sex, religion, marital status, or
> handicap be excluded from participation in, be denied the benefits of,
> or be otherwise subjected to discrimination under any program or
> activity receiving federal financial assistance from the Department of
> Agriculture or any agency thereof.***

**3. Part 618.07**

-   Change the formula in 618.07 (c) to:

***Db~15~ = \[(LEP/100) + 1\]^3^ X Db~moist~***

***where Db~15~ = bulk density 15 bar,***

***LEP = linear extensibility percent adjusted to a \<2 mm basis.***

**4. Exhibit 618-7**

-   Change the 2nd formula in footnote 3 to:

***PI = LL - \[9 + 0.4(clay)\]***

**5. Part 618.18 Electrical Conductivity.**

**(b) Classes.**

-   Change class limits to:

***Nonsaline 0 - \< 2***

***Very slightly saline 2 - \< 4***

***Slightly saline 4 - \< 8***

***Moderately saline 8 - \< 16***

***Strongly saline [\>]{.underline} 16***

**6. Part 618.20**

-   Change 618.20 (a) (1) reference to ***M-145-91 (1995)***

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-   Add to the end of 618.20 (b) (2) the following:

> ***Under average conditions of good drainage and thorough compaction,
> the supporting value of a material as subgrade may be assumed as an
> inverse ratio to its group index, that is, a group index of 0
> indicates a "good" subgrade material and group index of 20 or greater
> indicates a "very poor" subgrade material.***

-   Add to the end of 618.20 (b) (3) the following:

> ***Negative group index is reported as zero (0).***
>
> ***For soils that are non-plastic and when the liquid limit cannot be
> determined, the group index shall be considered zero (0).***

**7. Part 618.26**

-   **(b) (1) Flooding frequency class**.

-   Change the last line of VERY RARE to: \... ***but at least 1 time in
    500 years.***

-   Change OCCASIONAL to: \... ***\> 5 to 50 percent chance of flooding
    in any year or \> 5 to 50 times in 100 years.***

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-   **(b) (2) Flooding duration classes.**

-   Change to:

> ***[Class]{.underline} [Duration]{.underline}***
>
> ***Extremely brief 0.1 to \< 4.0 hours***
>
> ***Very brief 4 to \< 48 hours***
>
> ***Brief 2 to \< 7 days***
>
> ***Long 7 days to \< 30 days***
>
> ***Very long [\>]{.underline} 30 days***

-   **(d) (4)**

-   Add to the end of the paragraph: ***Duration is estimated to the
    nearest hour up to 48 hours, then it is estimated to the nearest
    day.***

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-   **(e) Entries**

-   Add as the 2nd sentence: ***Flooding entries reflect the current
    existing and mapped condition with consideration for dams, levees,
    and other man-induced changes affecting flooding frequency and
    duration.***

**8. Part 618.46**

-   **(b) (2) Ponding frequency class.**

-   Change:

> ***NONE - No reasonable possibility of ponding, near 0 percent chance
> of ponding in any year; less than 1 chance in 100 years.***
>
> ***RARE - Ponding unlikely but possible under unusual weather
> conditions; from 1 to 5 percent chance of ponding any year or 1 to 5
> times in 100 years.***
>
> ***OCCASIONAL - Ponding is expected under usual weather conditions; \>
> 5 to 50 percent chance in any year or \> 5 to 50 times in 100
> years.***

-   **(c) (2) Ponding duration class.**

-   Change class limits to:

> ***VERY BRIEF \< 2 days***
>
> ***BRIEF 2 to \< 7 days***
>
> ***LONG 7 to \< 30 days***
>
> ***VERY LONG [\>]{.underline} 30 days***

**9. Part 618.61 (b)**

-   Add to end of paragraph (3): ***When the percent of surface fragment
    cover is greater than 80 percent, the fragments are then a distinct
    horizon and also described as a horizon.***

**10. Part 618.71**

-   **(a) Definition**. Change to: ***Water, satiated, is the estimated
    volumetric soil water content at or near zero bar tension, expressed
    as a percentage of the whole soil.***

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-   **(b) Significance.** Change 2nd sentence to: ***Satiated water
    content approximates the water content for the whole soil at
    saturated conditions.***

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-   **(b) Significance.** Change last sentence to: ***Correction for
    fragments is taken into account in calculating this entry.***

-   **(c) Estimation.** Change formula to: ***Satiated water % = (total
    porosity % - entrapped air %) (100 - % volume fragments)***

-   **(d) Entries.** Change the valid entries to: ***10 to 70 percent***

**11. Exhibit 627-5 Conventional and Special Symbols Legend,
NRCS-SOI-37A**

-   Add ***Point and line features*** as soil delineations

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-   Change definitions on the back of the 37A to:

> ***BLO Blowout A small saucer-, cup-, or trough-shaped hollow or
> depression formed by wind erosion on a preexisting sand deposit.
> Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***BPI Borrow pit An open excavation from which soil and underlying
> material have been removed usually for construction purposes.
> Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***CLA Clay spot A spot where the surface layer is silty clay or clay
> in areas where the surface layer of the named soils in the surrounding
> map unit is sandy loam, loam, silt loam, or coarser.***
>
> ***DEP Depression, closed A shallow, saucer-shaped area that is
> slightly lower on the landscape than the surrounding area and is
> without a natural outlet for surface drainage. Typically \_\_\_\_\_to
> \_\_\_\_\_acres.***
>
> ***ESB Escarpment, bedrock A relatively continuous and steep slope or
> cliff produced by erosion or faulting, which breaks the general
> continuity of more gently sloping land surfaces. Exposed material is
> hard or soft bedrock.***
>
> ***ESO Escarpment, other A relatively continuous and steep slope or
> cliff that generally is produced by erosion but can be produced by
> faulting, which breaks the continuity of more gently sloping land
> surfaces. Exposed earthy material is nonsoil or very shallow soil.***
>
> ***GPI Gravel pit An open excavation from which soil and underlying
> material have been removed and used, without crushing, as a sourve of
> sand or gravel. Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***GRA Gravelly spot A spot where the surface layer has more than 35
> percent, by volume, rock fragments that are mostly less than 3 inches
> in diameter in an area of surrounding soil with less than 15 percent
> fragments. Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***GUL Gully A small channel with steep sides cut by running water and
> through which water ordinarily runs only after a rain or after ice or
> snow melts. It generally is an obstacle to wheeled vehicles and is too
> deep to be obliterated by ordinary tillage.***
>
> ***LDF Landfill An area of accumulated waste products of human
> habitation that can be above or below natural ground level. Typically
> \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***LAV Lava flow A solidified body of rock formed through lateral,
> surficial outpouring of molten lava from a vent or fissure. Often
> lobate in shape. Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***LVS Levee An embankment that confines or controls water, especially
> one built along the banks of a river to prevent overflow on
> lowlands.***
>
> ***MAR Marsh or swamp A water-saturated, very poorly drained area,
> intermittently or permanently covered by water. Marsh areas are
> dominantly vegetated by sedges, cattails, and rushes. Swamps are
> dominantly vegetated by trees or shrubs. Not used in map units where
> poorly drained or very poorly drained soils are the named components.
> Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***MPI Mine or quarry An open excavation from which soil and
> underlying material are removed and bedrock is exposed. Also denotes
> surface openings to underground mines. Typically \_\_\_\_\_to
> \_\_\_\_\_acres.***
>
> ***MIS Miscellaneous water Small, man-made water area that is used for
> industrial, sanitary, or mining applications and contains water most
> of the year. Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***WAT Perennial water Small, natural or man-made lake, pond, or pit
> that contains water most of the year. Typically \_\_\_\_\_to
> \_\_\_\_\_acres.***
>
> ***ROC Rock outcrop An exposure of bedrock at the surface of the
> earth. Not used where the named soils of the surrounding map unit are
> shallow over bedrock or where "bedrock" is a named component of the
> map unit. Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***SAL Saline spot An area where the surface layer has an electrical
> conductivity of 8 mmhos cm^-1^ more than the surface layer of the
> named soils in the surrounding map unit, which have an EC of 2 mmhos
> cm^-1^ or less. Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***SAN Sandy spot A spot where the surface layer is loamy fine sand or
> coarser in areas where the surface layer of the named soils of the
> surrounding map unit is very fine sandy loam or finer.***
>
> ***ERO Severely eroded spot An area where on the average 75 percent or
> more of the original surface layer has been lost because of
> accelerated erosion. Not used in map units with component phases that
> are named severely eroded, very severely eroded, or gullied.***
>
> ***SLP Short, steep slope Narrow soil area that has slopes that are at
> least two slope classes steeper than the slope class of the
> surrounding map unit.***
>
> ***SNK Sinkhole A closed depression formed either by solution of the
> surficial rock or by collapse of underlying caves. Typically
> \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***SLI Slide or slip A prominent landform scar or ridge caused by
> fairly recent mass movement or descent of earthy material resulting
> from failure of earth or rock under shear stress along one or several
> surfaces. Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***SOD Sodic spot An area where the surface layer has a sodium
> adsorption ratio that is at least 10 more than the surface layer of
> the named soils in the surrounding map unit, which have a sodium
> adsorption ratio of 5 or less. Typically \_\_\_\_\_to
> \_\_\_\_\_acres.***
>
> ***SPO Spoil area A pile of earthy materials, either smoothed or
> uneven, resulting from human activity. Typically \_\_\_\_\_to
> \_\_\_\_\_acres.***
>
> ***STN Stony spot A spot where 0.01 to 0.1 percent of the surface is
> covered with rock fragments that are greater than 10 inches in
> diameter in areas where the surrounding soil has no surface stones.
> Typically \_\_\_\_\_to \_\_\_\_\_acres.***
>
> ***STV Very stony spot A spot where 0.1 to 3 percent of the surface is
> covered with rock fragments that are greater than 10 inches in
> diameter in areas where less than 0.01 percent of the surface of the
> surrounding soil is covered with stones. Typically \_\_\_\_\_to
> \_\_\_\_\_acres.***
>
> ***WET Wet spot A somewhat poorly drained to very poorly drained area
> that is at least two drainage classes wetter than the named soils in
> the surrounding map unit. Typically \_\_\_\_\_to \_\_\_\_\_acres.***

**12. Part 629**

-   Replace Part 629 in total with a 1998 version.