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NSSH Part 622

Interpretative Groups

622.00  Definition and Purpose

  1. Definition. Interpretative groups are specified land use and specific management groupings that are assigned to soil areas because combinations of soils have similar behavior for specified practices. Most are based on soil properties and other factors that directly influence the specific use of the soil.
     
  2. Purpose. Interpretative groups allow users of soil surveys to plan reasonable alternatives for the use and management of soils.
     

622.01  Policy and Responsibilities

  1. Policy. The soil criteria used to determine the rating are coordinated nationally. Data elements, classes, or groups that are used in national legislation have strict adherence to national procedures. Guides that are developed locally or by States to rate soil survey land classification and groups are reviewed according to the procedure discussed in Part 617, Section 617.05 of this handbook. Prime farmland, hydrologic soil groups, and other interpretative groups important to many different users are published in the soil survey report.
     
  2. Responsibilities. The state soil scientist is responsible for program-specific and State interpretative group assignments to  map units and soil components, as appropriate. The state soil scientist ensures that all nationally significant interpretative group assignments to map units and soil components are included in the official soil survey database.
     

622.02  Land Capability Classification

  1. Definition. Land capability classification is a system of grouping soils primarily on the basis of their capability to produce common cultivated crops and pasture plants without deteriorating over a long period of time.
     
  2. Classes. Land capability classification is subdivided into capability class and capability subclass nationally. Some States also assign a capability unit.
     
  3. Significance. Land capability classification has value as a grouping of soils. National Resource Inventory information, the Farmland Protection Policy Act, and many field office technical guides have been assembled according to these classes. The system has been adopted in many textbooks and has wide public acceptance. Some State legislation has used the system for various applications. Users should reference Agriculture Handbook No. 210 for a listing of assumptions and broad wording used to define the capability class and capability subclass.
     
  4. Application. All map unit components, including miscellaneous areas, are assigned a capability class and subclass. Agriculture Handbook No. 210 provides general guidance, and individual State guides provide assignments of the class and subclass applicable to the State. Land capability units can be used to differentiate subclasses at the discretion of the State. Capability class and subclass are assigned to map unit components in the official soil survey database.

    Exhibit 622-2 provides an overall schematic of some of the soil properties and qualities than can be used to assign land capability classes (LCC) to all map unit components. Exhibits 622-3 and 622-6 are State-specific guides used to assign land capability classes to all map unit components in the States of California and Indiana, respectively. They provide examples of the soil properties and qualities used to determine assignments of LCC. Exhibits 622-4 and 622-7 are examples of guides used to assign land capability subclasses to soil map unit components in the States of California and Indiana, respectively. Exhibit 622-5 is an example of a State-specific guide used to assign land capability units to soil map unit components in the State of California. None of these guides contains detailed information that applies to all soils of the United States. Criteria for the assignment of land capability classifications to map unit components should be developed for each State within national standards.

    For map unit components that occur wholly within a State for a major land resource area (MLRA) that does not extend into another State, the state soil scientists should work with the MLRA soil survey leaders in developing land capability class and subclass criteria that are within Agriculture Handbook No. 210. Where the same kind of map unit component extends beyond State boundaries, the soil survey regional director will provide technical leadership to state soil scientists, MLRA soil survey leaders, and others to achieve uniform land capability class and subclass criteria between the States, soil survey offices, and MLRA soil survey areas. The National Leader for Soil Survey Interpretations at the National Soil Survey Center provides technical assistance to the state soil scientists and the MLRA soil survey leaders in writing land capability class and subclass criteria and coordinates assignment of capability class and subclass to map unit components. This includes reviewing assigned class and subclass to lists of soils and miscellaneous areas and resolving coordination problems that may occur among States, soil survey offices, and soil survey regional offices.
     
  5. Categories
     
    1. Capability Class
       
      1. Definition. Capability class is the broadest category in the land capability classification system. Class codes I (1), II (2), III (3), IV (4), V (5), VI (6), VII (7), and VIII (8) are used to represent both irrigated and nonirrigated land capability classes.
         
      2. Classes and definitions. The following definitions, from Agriculture Handbook No. 210, have been slightly altered.

        Class I (1) soils have slight limitations that restrict their use.

        Class II (2) soils have moderate limitations that reduce the choice of plants or require moderate conservation practices.

        Class III (3) soils have severe limitations that reduce the choice of plants or require special conservation practices, or both.

        Class IV (4) soils have very severe limitations that restrict the choice of plants or require very careful management, or both.

        Class V (5) soils have little or no hazard of erosion but have other limitations, impractical to remove, that limit their use mainly to pasture, rangeland, forestland, or wildlife habitat.

        Class VI (6) soils have severe limitations that make them generally unsuited to cultivation and that limit their use mainly to pasture, rangeland, forestland, or wildlife habitat.

        Class VII (7) soils have very severe limitations that make them unsuited to cultivation and that restrict their use mainly to rangeland, forestland, or wildlife habitat.

        Class VIII (8) soils and miscellaneous areas have limitations that preclude their use for commercial plant production and limit their use mainly to recreation, wildlife habitat, water supply, or esthetic purposes.

    2. Capability Subclass
       
      1. Definition. Capability subclass is the second category in the land capability classification system. Class codes e, w, s, and c are used for land capability subclasses.
         
      2. Subclasses and definitions

        Subclass e is made up of soils for which the susceptibility to erosion is the dominant problem or hazard affecting their use. Erosion susceptibility and past erosion damage are the major soil factors that affect soils in this subclass.

        Subclass w is made up of soils for which excess water is the dominant hazard or limitation affecting their use. Poor soil drainage, wetness, a high water table, and overflow are the factors that affect soils in this subclass.

        Subclass s is made up of soils that have soil limitations within the rooting zone, such as shallowness of the rooting zone, stones, low moisture-holding capacity, low fertility that is difficult to correct, and salinity or sodium content.

        Subclass c is made up of soils for which the climate (the temperature or lack of moisture) is the major hazard or limitation affecting their use.

      3. Application. The subclass represents the dominant limitation that determines the capability class. Within a capability class, where the kinds of limitations are essentially equal, the subclasses have the following priority: e, w, s, and c. See the rules (shown below) on appropriate entries for capability subclass.
         
    3. Capability Unit
       
      1. Definition. Capability unit is the first category described in the land capability classification system. It is a grouping of one or more individual soil map units having similar potentials and continuing limitations or hazards.
         
      2. Application. Use of this category and definition of codes are State options. 
         
  6. Entries. Enter the appropriate land capability class for each map unit component, including miscellaneous areas. Enter the land capability subclass only for soil map unit components which are assigned to capability classes 2 through 7. Capability subclasses are not assigned to soil components in capability class I (1) and are not assigned to soil or miscellaneous area components in capability class VIII (8). Subclass e is not used with soil components assigned to capability class V (5). Enter the appropriate capability unit code, if one is to be used in the area. Allowable entries for capability class are I (1), II (2), III (3), IV (4), V (5), VI (6), VII (7), or VIII (8). Allowable entries for subclass are e, w, s, or c. Valid entries for capability unit are integers ranging from 1 to 99. Enter the nonirrigated land capability class for all map unit components, including miscellaneous areas. Enter the irrigated land capability class and subclass if the soil map unit component is irrigated or potentially will be irrigated.
     

622.03  Farmland Classification

  1. Definition. The farmland classification designates map units as prime farmland, farmland of statewide importance, farmland of local importance, or farmland of unique importance. Soil map units with components of prime farmland are classified as: prime where 50 percent or more of the components in the map unit composition are prime; of statewide importance where less than 50 percent of the components in the map unit are prime but a combination of lands of prime or statewide importance is 50 percent or more of the map unit composition; of local importance where less than 50 percent of the components in the map unit are of prime or statewide importance but the total of land of prime, statewide, and/or local importance is 50 percent or more of the map unit composition. All other soil map units are shown as not farmland unless they are designated as unique.

    1. Prime farmland is defined as land that has the best combination of physical and chemical characteristics for producing food, feed, forage, fiber, and oilseed crops and that is available for these uses. It has the combination of soil properties, growing season, and moisture supply needed to produce sustained high yields of crops in an economic manner if it is treated and managed according to acceptable farming methods. In general, prime farmland has an adequate and dependable water supply from precipitation or irrigation, a favorable temperature and growing season, an acceptable level of acidity or alkalinity, an acceptable content of salt or sodium, and few or no rocks. Its soils are permeable to water and air. Prime farmland is not excessively eroded or saturated with water for long periods of time, and it either does not flood frequently during the growing season or is protected from flooding. Users of the lists of prime farmland map units should recognize that soil properties are only one of several criteria that are necessary. Other considerations for prime farmland are the following:

      1. Land use. Prime farmland is designated independently of current land use, but it cannot be areas of water or urban or built-up land as defined for the National Resource Inventories. Map units that are complexes or associations containing components of urban land or other miscellaneous areas as part of the map unit name (i.e., major components) cannot be designated as prime farmland. The soil survey memorandum of understanding determines the scale of mapping, and local land use interests should be considered in designing map units.
         
      2. Flooding frequency. Some map units may include both prime farmland and land not prime farmland because of variations in flooding frequency.
         
      3. Irrigation. Some map units have areas with a developed irrigation water supply that is dependable and of adequate quality while other areas do not have such a supply. In these map units, only the irrigated areas meet the prime farmland criteria.
         
      4. Water table. Most map units are drained but a few undrained areas are included. Only the drained areas meet the prime farmland criteria.
         
      5. Wind erodibility. The product of I (soil erodibility) x C (climate factor) cannot exceed 60 to meet prime farmland criteria.
         
    2. Unique farmland is land other than prime farmland that is used for the production of specific high-value food and fiber crops. It has the special combination of soil quality, location, growing season, and moisture supply needed to economically produce sustained high-quality and/or high yields of a specific crop when treated and managed according to acceptable farming methods. Examples of such crops are citrus, tree nuts, olives, cranberries, fruit, and vegetables. The specific characteristics of unique farmland are the following:

      1. It is used for a specific high-value food or fiber crop;
         
      2. It has a moisture supply that is adequate for the specific crop (the supply is from stored moisture, precipitation, or a developed irrigation system); and
         
      3. It combines favorable factors of soil quality, growing season, temperature, humidity, air drainage, elevation, aspect, or other conditions, such as nearness to market, that favor the growth of a specific food or fiber crop.
         
  2. Significance. Farmland classification identifies the location and extent of the most suitable land for producing food, feed, fiber, forage, and oilseed crops. The Natural Resources Conservation Service (NRCS) has national leadership for the management and maintenance of the resource base that supports the productive capacity of American agriculture. This management and maintenance includes identifying, locating, and determining the extent of the most suitable land for producing food, feed, fiber, forage, and oilseed crops. Prime farmland information is one of the four designations of farmland. An NRCS state conservationist can approve and have recorded in the field office technical guide (FOTG) soil map units that meet the criteria for farmland of statewide and local importance if the units are capable of producing crops on farmable land. Farmable land is land in a jurisdiction for which cropland productivity index has been developed in the land evaluation (LE) part of Land Evaluation and Site Assessment (LESA). Unique farmland described above is recorded in the FOTG by approval of the NRCS state conservationist.
     
  3. Measurement. NRCS policy and procedures on farmland are published in the Code of Federal Regulations 7CFR657. This regulation is reproduced in Exhibit 622-1 for convenience. It is also available online at the following Web address: http://www.access.gpo.gov/nara/cfr/waisidx_99/7cfr657_99.html.
     
  4. Policy. State soil scientists prepare and maintain a current list of soil survey map units that meet the soil criteria for farmland. The list given in field office technical guides is for users concerned with only a single part of a subset of the State list. The state soil scientist ensures that farmland soil interpretations are made for all soil map units in the State. Prime farmland map units continuing across State lines are coordinated with the adjoining State.
     
  5. Entries. Enter the numerical code for the classification of each map unit. Soils of unique, statewide, or local importance are not prime farmland. Allowable entries and numerical choice codes are the following:

    0 – Not prime farmland.
    1 – All areas are prime farmland.
    2 – Prime farmland if drained.
    3 – Prime farmland if protected from flooding or not frequently flooded during the growing season.
    4 – Prime farmland if irrigated.
    5 – Prime farmland if drained and either protected from flooding or not frequently flooded during the growing season.
    6 – Prime farmland if irrigated and drained.
    7 – Prime farmland if irrigated and either protected from flooding or not frequently flooded during the growing season.
    8 – Prime farmland if subsoiled, completely removing the root-inhibiting soil layer.
    9 – Prime farmland if irrigated and the product of I (soil erodibility) × C (climate factor) does not exceed 60.
    10 – Prime farmland if irrigated and reclaimed of excess salts and sodium.
    30 – Farmland of statewide importance.
    32 – Farmland of statewide importance, if drained.
    33 – Farmland of statewide importance, if protected from flooding or not frequently flooded during the growing season.
    34 – Farmland of statewide importance, if irrigated.
    35 – Farmland of statewide importance, if drained and either protected from flooding or not frequently flooded during the growing season.
    36 – Farmland of statewide importance, if irrigated and drained.
    37 – Farmland of statewide importance, if irrigated and either protected from flooding or not frequently flooded during the growing season.
    38 – Farmland of statewide importance, if subsoiled, completely removing the root-inhibiting soil layer.
    39 – Farmland of statewide importance, if irrigated and the product of I (soil erodibility) × C (climate factor) does not exceed 60.
    40 – Farmland of statewide importance, if irrigated and reclaimed of excess salts and sodium.
    41 – Farmland of statewide importance, if drained or either protected from flooding or not frequently flooded during the growing season.
    42 – Farmland of statewide importance, if warm enough, and either drained or either protected from flooding or not frequently flooded during the growing season.
    43 – Farmland of statewide importance, if warm enough.
    44 – Farmland of statewide importance, if thawed.
    50 – Farmland of local importance.
    54 – Farmland of local importance, if irrigated.
    70 – Farmland of unique importance.

     

  6. Quality Control of Prime Farmland Map Units

    1. Determination of prime farmland map units in each State is based on guidelines provided by the National Soil Survey Center and the National LESA Handbook. A NASIS calculation has been developed to identify concerns in the classification of prime farmland based on soil properties. The calculation can be used for guidance but does not suffice as the sole determinant for prime farmland map units.
       
    2. Each prime farmland map unit must be documented, by either use of the calculation or by a statement of reasons that explain the decision.
       
    3. Some soil survey map units may meet the soil criteria for prime farmland, but additional investigation is needed before a final determination is made. The measures needed to qualify the soil as prime farmland are indicated by an appropriate footnote or in a parenthetic statement of explanation that follows the map unit name on the list.
       
    4. The Farmland Protection Policy Act Manual (available online at: http://directives.sc.egov.usda.gov/RollupViewer.aspx?hid=17119) addresses the criteria for statewide and locally important farmland. It explains the importance of a list of soil map units designated as farmland of statewide and local importance.
       

622.04  Highly Erodible Land – Highly Erodible Soil Map Unit List

  1. Definition. Highly erodible land is defined by the Sodbuster, Conservation Reserve, and Conservation Compliance parts of the Food Security Act of 1985 and the Food, Agriculture, Conservation, and Trade Act of 1990. Determinations for highly erodible land are based on an erodibility index as defined in the National Food Security Act Manual.
     
  2. Policy. Lists of highly erodible and potential highly erodible map units are maintained in the field office technical guide (available online at http://efotg.sc.egov.usda.gov/efotg_locator.aspx?map). Policy and procedures for developing and maintaining the lists are given in Part 511 of the National Food Security Act Manual, 5th edition, November 2010 (available at http://directives.sc.egov.usda.gov/RollupViewer.aspx?hid=29362).
     

622.05  Hydric Soils

  1. Definition. A hydric soil is a soil that formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part. Hydric soils along with hydrophytic vegetation and wetland hydrology are used to define wetlands.
     
  2. Policy.  The current criteria for generating a list of hydric soils is in the Federal Register, February 29, 2012, volume 77, number 40, page 12234. The reference for field identification of hydric soils and their delineation is Field Indicators of Hydric Soils of the United States: A Guide for Identifying and Delineating Hydric Soils, Version 7.0, 2010.

    States maintain current lists of hydric soil map units in the field office technical guide.
     

622.06  Ecological Sites

  1. Definition. An ecological site is a distinctive kind of land with specific physical characteristics that differs from other kinds of land in its ability to produce a distinctive kind and amount of vegetation. An ecological site is recognized and described on the basis of the characteristics that differentiate it from other sites in its ability to produce and support a characteristic plant community.

    Forestland ecological sites and rangeland ecological sites are separated based on the historic climax plant community that existed at the time of European immigration and settlement. A site type of “forestland” is assigned and described where a 25% overstory canopy of trees, as determined by crown perimeter-vertical projection, dominated this historic vegetation. A site type of “rangeland” is assigned where overstory tree production was not significant in the climax vegetation. For details on developing ecological site descriptions refer to the National Forestry Manual and the National Range and Pasture Handbook.
     
  2. Policy. Soil-ecological site correlation establishes the relationship between soil components and ecological sites. Ecological sites are correlated on the basis of soils and the resulting differences in species composition, proportion of species, and total production of the historic climax plant community. In some cases, it is necessary to extrapolate data on the composition and production of a plant community on one soil to describe the plant community on a similar soil for which no data are available. The separation of two distinct soil taxonomic units does not necessarily delineate two ecological sites. Likewise, some soil taxonomic units occur over broad environmental gradients and may support more than one distinctive historic climax plant community. Changes may be brought about by other influences, such as an increase or decrease in average annual precipitation.

    Ecological sites are correlated between States. Only one site ID should be given to a single site that occurs in adjacent States within the same MLRA. Refer to the National Forestry Manual and the National Range and Pasture Handbook for details on the policy for correlating ecological sites.
     
  3. Responsibilities. Soil scientists and the responsible discipline specialists work together to map soils and ecological sites. Essential activities include developing a soil survey memorandum of understanding (work plan), determining the composition of map units, preparing map legends, determining mapping intensity, and conducting necessary field reviews. State discipline specialists have the final responsibility for correlating ecological sites to the map unit component to ensure coordination among States and land use areas.
     

622.07  Windbreaks

  1. Definition. A windbreak is a living barrier of trees or a combination of trees and shrubs that is located adjacent to a farmstead, field, feedlot, or other area. It is established to protect soil resources, reduce wind erosion, conserve energy or moisture, control snow deposition, provide shelter for livestock or wildlife, or increase the natural beauty of an area. It is also called a field windbreak, feedlot windbreak, or farmstead windbreak, depending upon its intended use. Field windbreaks, often called shelterbelts, are long, narrow strips of trees and shrubs that are planted in a variety of patterns to check the movement of wind.
     
  2. Policy. Soil interpretations are made for all soils in all areas where windbreaks are a present or potential practice. These interpretations are to be included in field office technical guides, soil handbooks, and published soil surveys. Soil scientists work with foresters in preparing windbreak interpretations.

    Refer to the National Forestry Manual for forestland interpretations. Conservation Tree/Shrub Group is a forestland interpretation useful for windbreak planning (see Part 537.4,_Exhibit 537-15 of manual).
     

622.08  Wildlife Habitat

  1. Definition. The habitat of a particular animal is defined as the place where the animal lives. Each habitat is the entire environmental complex, both living and nonliving, that is present at the place occupied by the animal species. Ratings are based on soils in their described condition and do not consider existing vegetation, water sources, or the presence or absence of wildlife in the area. These factors need to be considered during the site evaluation and planning process in order to obtain total habitat quality.
     
  2. Policy. Soil interpretations can be developed for all soils that have the potential to provide some form of habitat to locally adapted wildlife species. Soil scientists and biologists work together to identify specific wildlife habitat elements and to develop the categorical lists for the local area. This information is based on the inherent capabilities of the soil to produce certain kinds of vegetation for use as wildlife habitat or as habitat that meets the specific requirements of an animal species. Part 512 of the National Biology Manual (available online at: http://directives.sc.egov.usda.gov//OpenNonWebContent.aspx?content=17895.wba) provides more information.
     

622.09  Plant Name, Common

  1. Definition. The common plant name is the common name, accepted by the State or region, for the plant species or genera.
     
  2. Entries. None required. The common plant name used in a specific State will be provided by the system from the PLANTS database (available online at: http://plants.usda.gov) to match the plant symbol entered elsewhere. Adjustment or additions can be made.
     

622.10  Plant Name, Scientific

  1. Definition. Scientific plant name is the full genus and species name with author. Refer to PLANTS, Plant List of Accepted Nomenclature, Taxonomy, and Symbols.
     
  2. Significance. This information is important for technology transfer and interchange.
     
  3. Entries. None required. The system will provide the scientific plant name to match the plant symbol entered elsewhere.
     

622.11  Ecosystem ID

  1. Definition. Ecosystem ID is an identifier that, in conjunction with ecosystem type, uniquely identifies a particular ecosystem. For example, for range sites, the combination of “ecosystem type = rangeland” and “ecosystem id = rangesite id” uniquely identifies a particular range site.
     
  2. Entries. Enter the unique ID for the ecosystem for each map unit component where needed. Valid entries are combinations of numbers and/or letters up to 10 characters in length.
     

622.12  Ecosystem Name

  1. Definition. Ecosystem name is the descriptive name of a particular ecosystem. For example, “Loamy Upland” is a name of a rangeland ecological site.
     
  2. Entries. Enter the appropriate name of the ecosystem for each map unit component where needed.
     

622.13  Ecosystem Type

  1. Definition. Ecosystem type is the type of ecosystem.
     
  2. Classes. The choices for ecosystem type are:
    1. grazeable forest
    2. hayland
    3. native pasture
    4. pasture
    5. rangesite
       
  3. Entries. Enter the ecosystem type name for each map unit component where needed.
     

622.14  Earth Cover, Kind

  1. Definition. Earth cover, kind, is the natural or artificial material that is observed to cover a portion of the earth’s surface. It is determined (at least conceptually) as a vertical projection downward. There are two levels of categories.
     
  2. Significance. Earth cover, kind, is useful in assessing soils for use and management and monitoring for soil health. Identifying earth cover, kind, is important when linking to National Resources Inventory (NRI) data.

    Soil data ranges included in the map unit records in NASIS may be narrowed by indicating the cover type present for each map unit component.

    Significant differences for interpretations between the major cover types can be shown by designating each map unit component with the appropriate cover types.

    Earth cover, kind, is divided into two levels. The second is a subdivision of the first.
     
  3. Earth Cover Kind Level One Classes. The seven Level One classes correspond to the Level One categories used in the National Resources Inventory. See the document: Instructions for Collecting 1992 National Resources Inventory Sample Data. The definitions have been slightly altered.

    1. Crop cover. The cover lasting the full cropping cycle (which includes land preparation, leaving a post-harvest residue cover of annual or perennial herbaceous plants that are cultivated or harvested or both) in the production of food, feed, oil, and fiber other than wood and excluding hay and pasture.
       
    2. Grass/herbaceous cover. Non-woody vegetative cover (>50% grass, grass-like, or forb cover) composed of annual or perennial grasses, grass-like plants (sedges/rushes), forbs (including alfalfa and clovers), mosses, lichens, and ferns.
       
    3. Tree cover. Vegetative cover (>25% tree canopy cover) recognized as woody plants which usually have one perennial stem, a definitely formed crown of foliage, and a mature height of at least 4 meters. This category contains all trees, even those planted for the purpose of producing food or ornamentals, including Christmas trees. It also includes those lands which have been harvested of trees, even those that have been clear cut but will return to tree cover.
       
    4. Shrub cover. Vegetative cover (>50% shrub canopy cover) composed of multi-stemmed, woody plants, and single-stemmed species that attain less than 4 meters in height at maturity. This category contains all shrubs and woody vines, even those planted for the purpose of producing food.
       
    5. Barren land. Nonvegetative (<5% vegetated cover) natural cover on soils that commonly have a limited capacity to support vegetation and have a surface layer of sand, rock, thin soil, or permanent ice or snow. This category also includes bare soil resulting from construction activities and extractive activities, such as mining.
       
    6. Artificial cover. Nonvegetative cover either made or modified by human activities that prohibit or restrict vegetative growth and water penetration. Examples include highways, rooftops, road surfaces, paved and stone surface parking areas, sidewalks, and driveways.
       
    7. Water cover. Earth covered by water in a fluid state. This category includes seasonally frozen areas.
       
    Code Class
    C Crop cover
    G Grass/herbaceous cover
    T Tree cover
    S Shrub cover
    B Barren land
    A Artificial cover
    W Water cover
  1. Earth Cover Kind Level Two Classes. The 28 Level Two classes are grouped as subdivisions of Level One classes (except water cover) as follows:
    		
    Level 1:    Crop cover
    Level 2
    
    (1)         Row crops.—Examples are corn, soybeans, cotton, tomatoes, and tulips.
    (2)         Close-grown crops.—Examples are wheat, rice, oats, and rye.
    
    Level 1:    Grass/herbaceous cover
    Level 2
    
    (3)         Rangeland, grassland (<10% trees, <20% shrubs).—This subdivision includes 
                rangeland used for hayland, with plants such as bluestems, mixed midgrasses,
    	   mixed midgrasses, and shortgrasses.
    (4)         Rangeland, savanna.—10 to 25% tree cover
    (5)         Rangeland, shrubby.—20 to 50% shrub cover. (e.g., sumac, sagebrush, mesquite)
    (6)         Rangeland, tundra
    (7)         Pastureland, tame.—Examples are fescues, bromegrass, timothy, and lespedeza.
    (8)         Hayland.—Examples are fescues, bromegrass, timothy, and alfalfa.
    (9)         Marshland.—Examples are grasses and grass-like plants.
    (10)        Other grass/herbaceous cover
    
    Level 1: Tree cover
    Level 2
    
    (11)        Crop trees.—Examples are apples, pecans, date palms, citrus, ornamental
    	   nursery stock, and Christmas trees.
    (12)        Conifers.—Examples are spruce, pines, and Douglas-fir.
    (13)        Hardwoods.—Examples are oak, hickory, elm, and aspen.
    (14)        Intermixed conifers and hardwoods.—An example is an oak-pine mix.
    (15)        Tropical.—Examples are mangrove and royal palms.
    (16)        Swamp.—Trees and shrubs.
    (17)        Other tree cover
    
    Level 1: Shrub cover
    Level 2
    
    (18)        Crop shrubs.—Examples are filberts, blueberry, and ornamentals used as
    	   nursery stock.
    (19)        Crop vines.—Examples are grapes, blackberries, and raspberries.
    (20)        Native shrubs.—Examples are creosote bush, shrub live oak, sagebrush, and
    	   mesquite. (Includes rangeland with >50% shrub cover.)
    (21)        Other shrub cover.
    
    Level 1: Barren land
    Level 2
    
    (22)        Rock
    (23)        Sand and gravel
    (24)        Culturally induced barren.—Examples are saline seeps, mines, quarries, and
    	   oil-waste land.
    (25)        Permanent snow and ice
    (26)        Other barren.—Examples are playas and badland. Excludes areas with
    	   culturally induced earth cover.
    
    Level 1: Artificial cover
    Level 2
    
    (27)        Rural transportation.—Examples are highways and railroads.
    (28)        Urban and built-up.—Examples are cities, towns, farmsteads, and industrial
    	   sites.
  2. Entries. Enter the applicable Earth Cover Kind Level One class for each map unit component. Enter the applicable Earth Cover Kind Level Two class as appropriate.
     

Exhibit 622-1—Prime and Unique Farmlands

The Code of Federal Regulations for title 7 part 657 are maintained at the following website: http://www.gpoaccess.gov/cfr/index.html
The January 1, 1999 version was amended on September 25, 2000 with the changes published in the Federal Register as follows:
[Federal Register: September 25, 2000 (Volume 65, Number 186)]
[Rules and Regulations]
[Page 57537-57538]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25se00-2]


DEPARTMENT OF AGRICULTURE

Natural Resources Conservation Service

7 CFR Part 657

Prime and Unique Farmlands--Important Farmlands Inventory

AGENCY: Natural Resources Conservation Service, Agriculture.

ACTION: Final rule.


SUMMARY: The Natural Resources Conservation Service is amending its regulations regarding responsibilities for conducting important farmland inventories under the Federal Crop Insurance Reform and Department of Agriculture Reorganization Act of 1994 (the 1994 Act). The amendments reflect changes to individual and organizational titles made since the regulations were originally drafted.

EFFECTIVE DATE: September 25, 2000.

FOR FURTHER INFORMATION CONTACT: Horace Smith, Division Director, Soil Survey Division, Natural Resources Conservation Service, P.O. Box 2890, Washington, D.C. 20013; 202-720-1820.

SUPPLEMENTARY INFORMATION: This final rule makes corrections to nomenclature in the regulations for conducting important farmland inventories (7 CFR [[Page 57538]] Part 657, Subpart A.) Since the implementing legislation was passed, the names of the offices and titles of officials charged with conducting important farmland inventories have changed. This amendment reflects those changes. In addition, this rule amends the authority citation to clarify the list of statutory authorities for the inventories.

These rules are not expected to have significant economic impact under the criteria of the Regulatory Flexibility Act. They will not impose information collection requirements under the provisions of the Paperwork Reduction Act of 1980, 44 U.S.C. Chapter 35.

List of Subjects in 7 CFR Part 657

Farmlands.

For the reasons set forth above, Subpart A, Part 657 of Chapter VI of Title 7 of the Code of Federal Regulations is amended as follows:

PART 657 -- PRIME AND UNIQUE FARMLAND

Subpart A--Important Farmlands Inventory

1. The authority citation for Subpart A, Part 657 is revised to read as follows:
Authority: 7 U.S.C. 1010a; 16 U.S.C. 590a-590f; 42 U.S.C. 3271-3274.

Sec. 657.4 [Amended]

2. Section 657.4(a)(3)(iii) is amended by revising "NRCS Technical Service Centers (TSC's). (See 7 600.3, 600.6)" to read "National Soil Survey Center. (see 7 CFR 600.2(c), 600.6)".

3. Section 657.4(a)(4) is amended by revising the first sentence to read as follows: "Coordinate soil mapping units that qualify as prime farmlands with adjacent States, including Major Land Resource Area Offices (see 7 CFR 600.4, 600.7) responsible for the soil series."

4. Section 657.4(a)(6) is amended by revising "Administrator" to read "Chief".

5. Section 657.4(b) is amended by revising the heading and the first sentence to read as follows: "National Soil Survey Center. The National Soil Survey Center is to provide requested technical assistance to State Conservationists and Major Land Resource Area Offices in inventorying prime and unique farmlands (see 7 CFR 600.2(c)(1), 600.4, 600.7)."

6. Section 657.4(c) is amended by revising "Assistant Administrator for Field Services (See 7 CFR 600.2)" to read "Deputy Chief for Soil Survey and Resource Assessment (see 7 CFR 600.2(b)(3))".

Signed in Washington, D.C. on September 14, 2000.
Pearlie S. Reed, Chief.
[FR Doc. 00-24525 Filed 9-22-00; 8:45 am]
BILLING CODE 3410-16-P


CHAPTER VI--NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF AGRICULTURE

PART 657--PRIME AND UNIQUE FARMLANDS
[Code of Federal Regulations]
[Title 7, Volume 6, Parts 400 to 699]
[Revised as of January 1, 1999] [Amended September 25, 2000]
From the U.S. Government Printing Office via GPO Access
[CITE: 7CFR657.1; 7CFR657.2; 7CFR657.3; 7CFR657.4; 7CFR657.5.]

[beginning Page 699]

TITLE 7--AGRICULTURE

DEPARTMENT OF AGRICULTURE

PART 657--PRIME AND UNIQUE FARMLANDS--Table of Contents

Subpart A--Important Farmlands Inventory

Section 657.1 -- Purpose
Section 657.2 -- Policy
Section 657.3 -- Applicability
Section 657.4 -- NRCS Responsibilities
Section 657.5 -- Identification of Important Farmlands

Sec. 657.1  Purpose.

NRCS is concerned about any action that tends to impair the productive capacity of American agriculture. The Nation needs to know the extent and location of the best land for producing food, feed, fiber forage, and oilseed crops. In addition to prime and unique farmlands, farmlands that are of statewide and local importance for producing these crops also need to be identified

Sec. 657.2  Policy.

It is NRCS policy to make and keep current an inventory of the prime farmland and unique farmland of the Nation. This inventory is to be carried out in cooperation with other interested agencies at the national, state, and local levels of government. The objective of the inventory is to identify the extent and location of important rural lands needed to produce food, feed, fiber, forage, and oilseed crops.

Sec. 657.3  Applicability.

Inventories made under this memorandum do not constitute a designation of any land area to a specific land use. Such designations are the responsibility of appropriate local and state officials.

Sec. 657.4  NRCS responsibilities.

  1. State Conservationist. Each NRCS State Conservationist is to:
    1. Provide leadership for inventories of important farmlands for the State, county, or other subdivision of the State. Each is to work with appropriate agencies of State government and others to establish priorities for making these inventories.
    2. Identify the soil mapping units within the State that qualify as prime. In doing this, State Conservationists, in consultation with the cooperators of the National Cooperative Soil Survey, have the flexibility to make local deviation from the permeability criterion or to be more restrictive for other specific criteria in order to assure the most accurate identification of prime farmlands for a State. Each is to invite representatives of the Governor's office, agencies of the State government, and others to identify farmlands of statewide importance and unique farmlands that are to be inventoried within the framework of this memorandum.
    3. Prepare a statewide list of:
      1. Soil mapping units that meet the criteria for prime farmland;
      2. Soil mapping units that are farmlands of statewide importance if the criteria used were based on soil information; and
      3. Specific high-value food and fiber crops that are grown and, when combined with other favorable factors, qualify lands to meet the criteria for unique farmlands. Copies are to be furnished to NRCS Field Offices and to National Soil Survey Center. (see 7 CFR 600.2(c), 600.6)
    4. Coordinate soil mapping units that qualify as prime farmlands with adjacent States, including Major Land Resource Area Offices (see 7 CFR 600.4, 600.7) responsible for the soil series.
      Since farmlands of statewide importance and unique farmlands are designated by others at the State level, the soil mapping units and areas identified need not be coordinated among States.
    5. Instruct NRCS District Conservationists to arrange local review of lands identified as prime, unique, and additional farmlands of statewide importance by Conservation Districts and representatives of local agencies. This review is to determine if additional farmland should be identified to meet local decision making needs.
    6. Make and publish each important farmland inventory on a base map of national map accuracy at an intermediate scale of 1:50,000 or 1:100,000. State Conservationists who need base maps of other scales are to submit their requests with justification to the Chief for consideration.
  2. National Soil Survey Center. The National Soil Survey Center is to provide requested technical assistance to State Conservationists and Major Land Resource Area Offices in inventorying prime and unique farmlands (see 7 CFR 600.2(c)(1), 600.4, 600.7). This includes reviewing statewide lists of soil mapping units that meet the criteria for prime farmlands and resolving coordination problems that may occur among States for specific soil series or soil mapping units.
  3. National Office. The Deputy Chief for Soil Survey and Resource Assessment (see 7 CFR 600.2(b)(3)) is to provide national leadership in preparing guidelines for inventorying prime farmlands and for national statistics and reports of prime farmlands.

Sec. 657.5  Identification of important farmlands.

  1. Prime farmlands--
    1. General. Prime farmland is land that has the best combination of physical and chemical characteristics for producing food, feed, forage, fiber, and oilseed crops, and is also available for these uses (the land could be cropland, pastureland, rangeland, forest land, or other land, but not urban built-up land or water). It has the soil quality, growing season, and moisture supply needed to economically produce sustained high yields of crops when treated and managed, including water management, according to acceptable farming methods. In general, prime farmlands have an adequate and dependable water supply from precipitation or irrigation, a favorable temperature and growing season, acceptable acidity or alkalinity, acceptable salt and sodium content, and few or no rocks. They are permeable to water and air. Prime farmlands are not excessively erodible or saturated with water for a long period of time, and they either do not flood frequently or are protected from flooding. Examples of soils that qualify as prime farmland are Palouse silt loam, 0 to 7 percent slopes; Brookston silty clay loam, drained; and Tama silty clay loam, 0 to 5 percent slopes.
    2. Specific criteria. Prime farmlands meet all the following criteria: Terms used in this section are defined in USDA publications: “Soil Taxonomy, Agriculture Handbook 436”; “Soil Survey Manual, Agriculture Handbook 18”; “Rainfall-erosion Losses From Cropland, Agriculture Handbook 282”; “Wind Erosion Forces in the United States and Their Use in Predicting Soil Loss, Agriculture Handbook 346”; and “Saline and Alkali Soils, Agriculture Handbook 60.”
      1. The soils have:
        1. Aquic, udic, ustic, or xeric moisture regimes and sufficient available water capacity within a depth of 40 inches (1 meter), or in the root zone (root zone is the part of the soil that is penetrated or can be penetrated by plant roots) if the root zone is less than 40 inches deep, to produce the commonly grown cultivated crops (cultivated crops include, but are not limited to, grain, forage, fiber, oilseed, sugar beets, sugarcane, vegetables, tobacco, orchard, vineyard, and bush fruit crops) adapted to the region in 7 or more years out of 10; or
        2. Xeric or ustic moisture regimes in which the available water capacity is limited, but the area has a developed irrigation water supply that is dependable (a dependable water supply is one in which enough water is available for irrigation in 8 out of 10 years for the crops commonly grown) and of adequate quality; or,
        3. Aridic or torric moisture regimes and the area has a developed irrigation water supply that is dependable and of adequate quality; and,
      2. The soils have a temperature regime that is frigid, mesic, thermic, or hyperthermic (pergelic and cryic regimes are excluded). These are soils that, at a depth of 20 inches (50 cm), have a mean annual temperature higher than 32 deg. F (0 deg. C). In addition, the mean summer temperature at this depth in soils with an O horizon is higher than 47 deg. F (8 deg. C); in soils that have no O horizon, the mean summer temperature is higher than 59 deg. F (15 deg. C); and,
      3. The soils have a pH between 4.5 and 8.4 in all horizons within a depth of 40 inches (1 meter) or in the root zone if the root zone is less than 40 inches deep; and,
      4. The soils either have no water table or have a water table that is maintained at a sufficient depth during the cropping season to allow cultivated crops common to the area to be grown; and,
      5. The soils can be managed so that, in all horizons within a depth of 40 inches (1 meter) or in the root zone if the root zone is less than 40 inches deep, during part of each year the conductivity of the saturation extract is less than 4 mmhos/cm and the exchangeable sodium percentage (ESP) is less than 15; and,
      6. The soils are not flooded frequently during the growing season (less often than once in 2 years); and,
      7. The product of K (erodibility factor) x percent slope is less than 2.0, and the product of I (soils erodibility) x C (climatic factor) does not exceed 60; and
      8. The soils have a permeability rate of at least 0.06 inch (0.15 cm) per hour in the upper 20 inches (50 cm) and the mean annual soil temperature at a depth of 20 inches (50 cm) is less than 59 deg. F (15 deg. C); the permeability rate is not a limiting factor if the mean annual soil temperature is 59 deg. F (15 deg. C) or higher; and,
      9. Less than 10 percent of the surface layer (upper 6 inches) in these soils consists of rock fragments coarser than 3 inches (7.6 cm).
  2. Unique farmland--
    1. General. Unique farmland is land other than prime farmland that is used for the production of specific high value food and fiber crops. It has the special combination of soil quality, location, growing season, and moisture supply needed to economically produce sustained high quality and/or high yields of a specific crop when treated and managed according to acceptable farming methods. Examples of such crops are citrus, tree nuts, olives, cranberries, fruit, and vegetables.
    2. Specific characteristics of unique farmland.
      1. Is used for a specific high-value food or fiber crop;
      2. Has a moisture supply that is adequate for the specific crop; the supply is from stored moisture, precipitation, or a developed-irrigation system;
      3. Combines favorable factors of soil quality, growing season, temperature, humidity, air drainage, elevation, aspect, or other conditions, such a nearness to market, that favor the growth of a specific food or fiber crop.
  3. Additional farmland of statewide importance. This is land, in addition to prime and unique farmlands, that is of statewide importance for the production of food, feed, fiber, forage, and oil seed crops. Criteria for defining and delineating this land are to be determined by the appropriate State agency or agencies. Generally, additional farmlands of statewide importance include those that are nearly prime farmland and that economically produce high yields of crops when treated and managed according to acceptable farming methods. Some may produce as high a yield as prime farmlands if conditions are favorable. In some States, additional farmlands of statewide importance may include tracts of land that have been designated for agriculture by State law.
  4. Additional farmland of local importance. In some local areas there is concern for certain additional farmlands for the production of food, feed, fiber, forage, and oilseed crops, even though these lands are not identified as having national or statewide importance. Where appropriate, these lands are to be identified by the local agency or agencies concerned. In places, additional farmlands of local importance may include tracts of land that have been designated for agriculture by local ordinance.
     

Exhibit 622-2—Example of Soil Properties and Qualities Used to Assign Land Capability Classes

  Land Capability Class — Degree of Limitations, Restrictions, or Hazards
Soil Properties I (1) II (2) III (3) IV (4) V (5) VI (6) VII (7) VIII (8)
Minimum depth to lithic or paralithic contact (in) 40 20 20 10 40 20 10 <10
Soil reaction (pH) Favorable reaction:
easy to modify
Unfavorable reaction:
high lime or difficult to modify
Unfavorable reaction: very difficult to modify Not generally class-determining Cat clays; unfavorable reaction: impractical to modify
Surface texture class or term used in lieu of texture SL, FSL, VFCL, L, SIL, SCL, CL, SICL; or LS, LFS, S, FS (if less than 20 in. thick) LS, LFS, S, FS; or SIC, SC, C (<60% clay); or MUCK,
MUCKY PEAT, PEAT
C (≥60% clay) COS, LCOS Same criteria as class I Same criteria as class II Same criteria as class III Not class-determining
Available water capacity (in inches to a depth of 48 inches) >9 >6 to ≤9 >3 to ≤6 ≤3 Same criteria as class I Same criteria as class II Same criteria as class III Not class-determining
Permeability Moderately slow to moderately rapid Slow or rapid Very slow or very rapid Not class-determining Same criteria as class I Same criteria as class II Same criteria as class III Not class-determining
Drainage class Well or moderately well Moderately well or somewhat poorly Somewhat poorly or poorly Poor Not class-determining
Water table during the growing season (minimum depth in inches) 48–Does not interfere with crop production 30–Delays planting or harvesting 18–Crop selection moderately affected 12–Crop selection severely affected 48 <12–Ponding

Class II or III after drainage

<12–Ponding

Class IV after drainage

<12–Ponding

Cannot be drained

Flooding (overflow) None during growing season. Crop selection not restricted Rare –Occasional. Slight crop damage; 0 to 20% yield reduction or crop selection slightly affected Occasional. Moderate crop damage; 20-35% yield reduction or crop selection moderately affected Frequent. Severe crop damage; 35-50% yield reduction or crop selection severely affected Frequent - Prevents normal production of crops

If protected from flooding:
Class V equals Class I
Class VI equals Class II or III
Class VII equals Class IV

If landform is a tidal flat: Class VIII

Salinity (mmhos/cm) <2 ≥2 to ≤4 >4 to ≤8 >8 to ≤16 <2 >16 to ≤30 >30 to ≤40 >40
Stones or boulders only on surface (%) <0.1 ≥0.1 to <3.0 ≥3.0 to <15.0 ≥3.0 to <15.0 ≥15.0 to <50.0 ≥15.0 to <50.0 ≥50.0 to <90.0 ≥90.0
All rock fragments in surface and control section (%) <15 ≥15 to <35 ≥35 to <60 ≥35 to <60 <15 Not class-determining
Rock outcrop (%) <0.1 ≥0.1 to <2.0 ≥2 to <10 ≥2 to <10 <0.1 ≥10 to <50 ≥50 to <90 ≥90
Frost-free period (days) >140 >100 to ≤140 >70 to ≤100 50 to ≤70 Not class-determining
Effective precipitation (inches) ≥44 ≥31 to <44 ≥25 to <31 ≥19 to <25 Not class-determining ≥10 to <19 <10 Not class-determining
Cumulative days dry in soil moisture control section <135 ≥135 to <180 ≥180 to <220 ≥180 to <220 Not class-determining ≥220 to <270 ≥270 ≥270
Taxonomic moisture subclass and moisture class (regime) Typic Udic or Udic Ustic Typic Ustic Aridic Ustic Aridic Ustic Not class-determining Ustic Aridic Typic Aridic
Slope: K factor of >32 2 5 8 12 2 25 Not class-determining
Slope: K factor of ≥20 to ≤32 3 6 12 18 3 25 Not class-determining
Slope: K factor of <20 4 8 15 25 4 35 Not class-determining
Erosion hazard None or slight Moderate Severe Very severe None or slight Not class-determining


Exhibit 622-3—Guide for Assigning Land Capability Classes to All Map Unit Components in California

Exhibit 622-3—Guide for Assigning Land Capability Classes to All Map Unit Components in California.


High resolution JPEG
(3073x2958, 1.17 MB)
 

Exhibit 622-4—Guides for Assigning Land Capability Subclasses to Soil Map Unit Components in California

Exhibit 622-4—Guides for Assigning Land Capability Subclasses to Soil Map Unit Components in California.

 

 

 

 

 

 

 

 

 

 

 

 

 


High resolution JPEG
(2651x2412, 954 KB)
 

Exhibit 622-5—Guide for Assigning Land Capability Units to Soil Map Unit Components in California

Capability Unit Principal Soil Property or Limitation
1 Potential or actual wind or water erosion hazard
2 Drainage or overflow hazard (somewhat poorly drained or poorly drained, flooded, or ponded)
3 Slowly or very slowly permeable subsoil or substrata
4 Coarse or gravelly textures
5 Fine textured (i.e., fine or veryfine particle-size classes)
6 Salinity or sodicity, sufficient to constitute a continuing limitation or hazard
7 Stones, cobbles, or other rock fragments sufficient to interfere with tillage
8 Hardpan or hard unweathered bedrock within the root zone
9 Low inherent fertility, associated with strong acidity and low calcium
10 High organic matter and/or fiber content (i.e., peat, mucky peat, and muck)
11 Coarse sandy or very gravelly substrata that limit root penetration and moisture retention


Exhibit 622-6—Guide for Assigning Land Capability Classes to All Map Unit Components in Indiana

Exhibit 622-6—Guide for Assigning Land Capability Classes to All Map Unit Components in Indiana.

High resolution JPEG (3037x2517, 952 KB)
 

Exhibit 622-7—Guide for Assigning Land Capability Subclasses to Soil Map Unit Components in Indiana

Soil Properties Subclass by Slope Classes1
A B C D2
I. Very deep through moderately deep soil depth classes
1. Moderate through rapid permeability
A. Excessively through rapidly permeable with the following general texture terms for the surface:
1. Fine textured
s e e e
2. Moderately fine textured
s 2,3 e e e
3. Medium textured
s 2,3 e e e
4. Moderately coarse textured, with or without textural B horizon
s 2,3 e e e
5. Coarse textured with textural B horizon3
s s e e
6. Coarse textured with little or no textural B horizon
s e s s
B. Poorly and very poorly drained
w w w w
C. Somewhat poorly drained with the following general texture terms for the surface:
1. Fine through moderately coarse textured
w e e e
2. Coarse textured with textural B horizon
w e e e
3. Coarse textured with little or no textural B horizon
w s s s
2. Moderately slow permeability
1. Well drained and moderately well drained
s e e e
2. Somewhat poorly drained
w e e e
3. Poorly drained and very poorly drained
w w w
3. Slow and very slow permeability
1. Well drained through excessively drained
s e e e
2. Moderately well drained
w e e e
3. Somewhat poorly drained
w e e e
4. Poorly drained and very poorly drained
w w w w
II. Shallow soil depth class
1. Well drained and moderately well drained
a. 10 to 20 inches to bedrock
s e e e
b. Less than 10 inches to bedrock
s s s s
2. Somewhat poorly drained through very poorly drained
w w w w
III. Saline and sodic soils (moderate or severe salinity or sodicity) s s e e
IV. Stony soils s s s s
V. Soils subject to damaging overflow w w

1 For soils in capability classes 2 through 7. Map unit components in capability classes 1 and 8 are excluded.
2 Same subclass applicable for E, F, and G slopes where they occur.
3 Includes normally droughty, fine to medium textured soils underlain by sand and gravel at depths of less than 20 inches.