From theSurface DownAn Introduction to Soil Surveysfor Agronomic Use

United StatesDepartment ofAgriculture

Natural ResourcesConservationService

National EmployeeDevelopment Staff

i

First printed November 1991Revised May 2000

Credits

Plates 1, 2, 3, 4, 5, 6, 10, 11, 12, and 17 are reprintedfrom Soils of the Great Plains, by Andrew R.Aandahl, by permission from the University ofNebraska Press. Copyright 1982 by the University ofNebraska Press.

Plates 9, 13, 14, 15, and 18 are from the author'scollection.

Plates 7 and 16 are by courtesy of Edward White, NaturalResources Conservation Service, Harrisburg, PA.

Plate 8 is by courtesy of John Kimble, Natural ResourcesConservation Service, Lincoln, NE.

Plate 19 is by courtesy of Douglas Wysocki, NaturalResources Consevation Service, Lincoln, NE.

Figures 1, 2, 3, 4, and 5 created by National EmployeeDevelopment Staff, U.S. Department of Agriculture,Natural Resources Conservation Service, Fort Worth,TX.

Figure 6 created from Soil Taxonomy: A Basic System ofSoil Classification for Making and Interpreting SoilSurveys, U.S. Department of Agriculture, NaturalResources Conservation Service, 1st edition, p. 471.

Figure 7 created from Evaluating Missouri Soils, by Dr. C.L. Scrivner, and James C. Baker, Circular 915,Extension Division, University of Missouri-Columbia.

Figure 8 created by U.S. Department of Agriculture,Natural Resources Conservation Service,Washington, DC.

Figures 9 and 10 reprinted from the Soil Survey of GentryCounty, Missouri.

Cover: Soil profile of Segno fine sandy loam, a Plinthic Paleudalf. Note thecharacteristic blocks of plinthite at 30 inches. Photo by Frankie F. Wheeler, NaturalResources Conservation Service, Temple, TX, and Larry Ratliff, Natural ResourcesConservation Service, Lincoln, NE.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programsand activities on the basis of race, color, national origin, sex, religion, age, disability,political beliefs, sexual orientation, or marital or family status. (Not all prohibited basesapply to all programs.) Persons with disabilities who require alternative means forcommunication of program information (Braille, large print, audiotape, etc.) shouldcontact USDA’s TARGET Center at (202) 720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity providerand employer.

ii

Contents

Introduction .......................................................................... 1Section 1: What are soil horizons? ..................................... 2Section 2: How is soil formed? ........................................... 3Section 3: What are the soil forming processes? ............... 5

Soil survey information ......................................................... 7Section 4: Soil properties.................................................... 7Section 5: Management interpretations ............................ 17Section 6: General soil information ................................... 21Section 7: Detailed soil information .................................. 24

Location of information ....................................................... 25Section 8: Location of soil properties and

interpretations............................................................... 25

References ......................................................................... 26

1

Introduction

Much of our life’s activities and pursuits arerelated and influenced by the behavior of thesoil around our houses, roads, septic and

sewage disposal systems, airports, parks, recreationsites, farms, forests, schools, and shopping centers.What is put on the land should be guided by the soil thatis beneath it.

Like snowflakes, no two soils are exactly the same.Surface as well as below the surface soil featureschange across landscapes (fig. 1). A grouping of soilshaving similar properties and similar behavior is called aseries. A series generally is named for a town or locallandmark. For example, the Mexico series is named fora town in north central Missouri. More than 20,000 soilseries have been named and described in the UnitedStates, and more are being defined each year.

In mapping, a soil series is further divided into aphase of a series by properties that are important tosoil use, such as surface texture and slope. Thesephases of soil series, once identified, all have acharacteristic behavior. The behavior for that kind ofsoil and individual phase is applicable no matter wherethe soil is observed.

One of the main references available to help land usersdetermine the potentials and limitations of soils is a soilsurvey. Copies of a soil survey for a specific county areavailable from the Natural Resources ConservationService office responsible for that county. Referencecopies are also available in the county or depositorylibraries. A soil survey is prepared by soil scientists whodetermine the properties of soil and predict soil behaviorfor a host of uses. These predictions, often called soilinterpretations, are developed to help users of soilsmanage the resource.

A soil survey generally contains soils data for onecounty, parish, or other geographic area, such as amajor land resource area. During a soil survey, soilscientists walk over the landscapes, bore holes withsoil augers, and examine cross sections of soil profiles.They determine the texture, color, structure, andreaction of the soil and the relationship and thickness ofthe different soil horizons. Some soils are sampled andtested at soil survey laboratories for certain soil propertydeterminations, such as cation-exchange capacity andbulk density.

The intent of this publication is to increase user under-standing of soils and acquaint them with the contents ofa soil survey and supplemental interpretations that areimportant to agronomic programs.

To be proficient in using soil survey data, a basicunderstanding of the concepts of soil development andof soil-landscape relationships is imperative. Thesetopics are covered briefly in the next three sections.

Figure 1. —Facts about soil.

1Soil scientist; formerly on the National Soil Survey Quality Assurance Staff, National Soil Survey Center, Natural Resources Conservation Service,

U.S. Department of Agriculture, Lincoln, Nebraska; currently, the State Soil Scientist in Utah.

From the Surface DownAn Introduction to Soil Surveys

for Agronomic Use

William D. Broderson1

Slope

Vegetation

Climate Erosion

Overflow

ChemicalProperties

TextureNutrient

SupplyingCapacity

Wetness

WaterSupplyingCapacity

PhysicalProperties

SOIL

2

Section 1: What are soil horizons?

Soils are deposited in or developed into layers.These layers, called horizons, can be seenwhere roads have been cut through hills, where

streams have scoured through valleys, or in other areaswhere the soil is exposed.

Where soil forming factors are favorable, five or sixmaster horizons may be in a mineral soil profile (fig. 2).Each master horizon is subdivided into specific layersthat have a unique identity. The thickness of each layervaries with location. Under disturbed conditions, suchas intensive agriculture, or where erosion is severe, notall horizons will be present. Young soils have fewermajor horizons, such as the bottom land soil in figure 3and the deep loess soil in plate 1.

Below the O horizon is the A horizon. The A horizonis mainly mineral material. It is generally darker thanthe lower horizons because of the varying amountsof humified organic matter (plates 4, 5). This horizonis where most root activity occurs and is usually themost productive layer of soil. It may be referred toas a surface layer in a soil survey. An A horizon thathas been buried beneath more recent deposits isdesignated as an “Ab” horizon (plate 2).

The E horizon generally is bleached or whitish inappearance (plates 6, 7, 8). As water moves downthrough this horizon, soluble minerals and nutrientsdissolve and some dissolved materials are washed(leached) out. The main feature of this horizon is theloss of silicate clay, iron, aluminum, humus, or somecombination of these, leaving a concentration of sandand silt particles.

Below the A or E horizon is the B horizon, or subsoil(plates 4, 6). The B horizon is usually lighter colored,denser, and lower in organic matter than the Ahorizon. It commonly is the zone where leachedmaterials accumulate. The B horizon is further definedby the materials that make up the accumulation, suchas t in the form of Bt, which identifies that clay hasaccumulated. Other illuvial concentrations oraccumulations include iron, aluminum, humus,carbonates, gypsum, or silica. Soil not havingrecognizable concentrations within B horizons butshow color or structural differences from adjacenthorizons is designated Bw.

Still deeper is the C horizon or substratum (plate 1).The C horizon may consist of less clay, or other lessweathered sediments. Partially disintegrated parentmaterial and mineral particles are in this horizon.Some soils have a soft bedrock horizon that is giventhe designation Cr (plate 9). C horizons described as2C consist of different material, usually of an olderage than horizons which overlie it.

The lowest horizon, the R horizon, is bedrock (plate 9).Bedrock can be within a few inches of the surface ormany feet below the surface. Where bedrock is verydeep and below normal depths of observation, an Rhorizon is not described.

The uppermost layer generally is an organic horizon,or O horizon. It consists of fresh and decaying plantresidue from such sources as leaves, needles,twigs, moss, lichens, and other organic materialaccumulations. Some organic materials were depositedunder water (plates 2, 3). The subdivisions Oa, Oe, andOi are used to identify levels of decomposition. The Ohorizon is dark because decomposition is producinghumus.

Figure 2.—A soil profile with five major horizons.

3

Section 2: How is soil formed?

Figure 3 illustrates a few common landscapes.Soils develop as a result of the interactions ofclimate, living organisms, and landscape

position as they influence parent material decompositionover time. Notice in this example how the soil profileschange from weakly developed to well developed withtime. Older terraces, or soils on second bottom posi-tions, usually have developed B horizons. Recent soilsdeposited in first bottom positions usually do not have adeveloped B horizon. Instead, they may have stratifiedlayers varying in thickness, texture, and composition.

Differences in climate, parent material, landscapeposition, and living organisms from one location toanother as well as the amount of time the material hasbeen in place all influence the soil forming process.

Five soil-forming factors• Parent material• Climate• Living organisms• Landscape position• Time

Parent material

Parent material refers to that great variety ofunconsolidated organic (such as fresh peat) and mineralmaterial in which soil formation begins. Mineral materialincludes partially weathered rock, ash from volcanoes,sediments moved and deposited by wind and water, orground up rock deposited by glaciers. The material hasa strong effect on the type of soil developed as well asthe rate at which development takes place. Soildevelopment may take place quicker in materials thatare more permeable to water (plate 6). Dense, massive,clayey materials can be resistant to soil formationprocesses (plate 5). In soils developed from sandyparent material, the A horizon may be a little darkerthan its parent material, but the B horizon tends to havea similar color, texture, and chemical composition (plate12).

Climate

Climate is a major factor in determining the kind ofplant and animal life on and in the soil. It determinesthe amount of water available for weathering mineralsand transporting the minerals and elements released.

Figure 3.—Landscape position, climate, time, organisms, and parent materials influence soil development.

A

B

CR

A

CC

AB

0

60"Well

DevelopedWeakly

DevelopedModeratelyDeveloped

0

60"

0

60"

Bedrock

Recent Alluvium

Old Alluvium

Soil Parent MaterialBedrock First Bottom–

FloodplainSecond Bottom–

TerraceSecond Bottom–

Terrace First Bottom–

Floodplain

Upland Upland

4

The soil in plate 10 developed in drier regions thanthe soil in plate 11. Climate through its influence onsoil temperature, determines the rate of chemicalweathering.

Warm, moist climates encourage rapid plant growth|and thus high organic matter production. Theopposite is true for cold, dry climates. Organic matterdecomposition is also accelerated in warm, moistclimates. Under the control of climate freezing, thawing,wetting, and drying break parent material apart.

Rainfall causes leaching. Rain dissolves some minerals,such as carbonates, and transports them deeper intothe soil. Some acid soils have developed from parentmaterials that originally contained limestone. Rainfallcan also be acid, especially downwind from industrialprocesses.

Living organisms

Plants affect soil development by supplying upper layerswith organic matter, recycling nutrients from lower toupper layers, and helping to prevent erosion. In general,deep rooted plants contribute more to soil developmentthan shallow rooted because the passages they createallow greater water movement, which in turn aids inleaching. Leaves, twigs, and bark from large plants fallonto the soil and are broken down by fungi, bacteria,insects, earthworms, and burrowing animals. Theseorganisms eat and break down organic matter releasingplant nutrients. Some change certain elements, such assulfur and nitrogen, into usable forms for plants.

Microscopic organisms and the humus they producealso act as a kind of glue to hold soil particles togetherin aggregates. Well-aggregated soil is ideal for providingthe right combination of air and water to plant roots.

Landscape position

Landscape position causes localized changes inmoisture and temperature. When rain falls on a

landscape, water begins to move downward by theforce of gravity, either through the soil or across thesurface to a lower elevation. Even though thelandscape has the same soil-forming factors of climate,organisms, parent material, and time, drier soils athigher elevations may be quite different from the wettersoils where water accumulates. Wetter areas may havereducing conditions that will inhibit proper root growthfor plants that require a balance of soil oxygen, water,and nutrients.

Steepness, shape, and length of slope are importantbecause they influence the rate at which water flowsinto or off the soil. If unprotected, soils on slopes mayerode leaving a thinner surface layer. Eroded soils tendto be less fertile and have less available water thanuneroded soils of the same series.

Aspect affects soil temperature. Generally, for most ofthe continental United States, soils on north-facingslopes tend to be cooler and wetter than soils on south-facing slopes. Soils on north-facing slopes tend to havethicker A and B horizons and tend to be less droughty.

Time

Time is required for horizon formation. The longer a soilsurface has been exposed to soil forming agents likerain and growing plants, the greater the development ofthe soil profile. Soils in recent alluvial or windblownmaterials, or soils on steep slopes where erosion hasbeen active may show very little horizon development,(plate 1).

Soils on older, stable surfaces generally have welldefined horizons because the rate of soil formation hasexceeded the rate of geologic erosion or deposition(plate 4). As soils age, many original minerals aredestroyed. Many new ones are formed. Soils becomemore leached, more acid, and more clayey. In many welldrained soils, the B horizons tend to become redderwith time (plates 6, 11).

5

The four major processes that change parentmaterial into soil are additions, losses,

translocations, and transformations.

Processes of soil formationAdditionsLossesTranslocationsTransformations

Additions

The most obvious addition is organic matter. As soon asplant life begins to grow in fresh parent material, organicmatter begins to accumulate. Organic matter gives ablack or dark brown color to surface layer (plates 4 and5). Even young soils may have a dark surface layer(plate 1). Most organic matter additions to the surfaceincrease the cation exchange capacity and nutrients,which also increase plant nutrient availability.

Other additions may come with rainfall or deposition bywind, such as the wind blown or eolian material (plate12). On the average, rainfall adds about 5 pounds ofnitrogen per acre per year. By causing rivers to flood,rainfall is indirectly responsible for the addition of newsediment to the soil on a flood plain.

Losses

Most losses occur by leaching. Water moving throughthe soil dissolves certain minerals and transports theminto deeper layers. Some materials, especially sodiumsalts, gypsum, and calcium carbonate, are relativelysoluble (plates 10, 11, and 13). They are removed earlyin the soil’s formation. As a result, soil in humid regionsgenerally does not have carbonates in the upperhorizons. Quartz, aluminum, iron oxide, and kaoliniticclay weather slowly. They remain in the soil and becomethe main components of highly weathered soil.

Fertilizers are relatively soluble, and many, such asnitrogen and potassium, are readily lost by leaching,either by natural rainfall or by irrigation water. Long-termuse of fertilizers based on ammonium may acidify thesoil and contribute to the loss of carbonates in someareas.

Oxygen, a gas, is released into the atmosphere bygrowing plants. Carbon dioxide is consumed by growing

plants, but lost to the soil as fresh organic matterdecays. When soil is wet, nitrogen can be changed to agas and lost to the atmosphere.

Solid mineral and organic particles are lost by erosion.Such losses can be serious because the material lost isusually the most productive part of the soil profile. Onthe other hand, the sediment relocated to lower slopepositions or deposited on bottom lands has the potentialto increase or decrease productive use of soils in thoseareas.

Translocations

Translocation means movement from one place toanother. In low rainfall areas, leaching often isincomplete. Water starts moving down through the soil,dissolving soluble minerals as it goes. There isn’tenough water, however, to move all the way through thesoil. When the water stops moving, then evaporates,salts are left behind. Soil layers with calcium carbonateor other salt accumulations form this way. If this cycleoccurs enough times, a calcareous hardpan can form.

Translocation upward and lateral movement is alsopossible. Even in dry areas, low-lying soils can have ahigh water table. Evaporation at the surface causeswater to move upward (plate 13). Salts are dissolved onthe way and are deposited on the surface as the waterevaporates (plate 14).

Transformations

Transformations are changes that take place in the soil.Microorganisms that live in the soil feed on freshorganic matter and change it into humus. Chemicalweathering changes parent material. Some minerals aredestroyed completely. Others are changed into newminerals. Many of the clay-sized particles in soil areactually new minerals that form during soil development.

Other transformations can change the form of certainmaterials. Iron oxides (ferric form) usually give soils ayellowish or reddish color. In waterlogged soils, how-ever, iron oxides lose some of their oxygen and arereferred to as being reduced. The reduced form of iron(ferrous) is quite easily removed from the soil byleaching. After the iron is gone, generally the leachedarea has a grayish or whitish color (plate 6).

Repeated cycles of saturation and drying create amottled soil (splotches of colored soil in a matrix of

Section 3: What are the soil forming processes?

6

different color). Part of the soil is gray because of theloss of iron, and part is a browner color where the ironoxide is not removed (plates 15 and 16). During long

periods of saturation, gray lined root channels develop.This may indicate a possible loss of iron or an additionof humus from decayed roots.

7

Section 4: Soil properties

Soil survey publications present a number ofproperties that pertain to agriculture. Someproperties relate to erosion, such as slope

gradient, and factors K and T. Others relate to plantgrowth, such as depth to layers, that restrict roots,available water capacity, salinity, and the capacity toretain and release plant nutrients. Some propertiespertain to the soil’s ability to retain soluble substancesthat may cause pollution of ground water, such asorganic matter or the need for additions of lime, suchas pH. Some properties, such as slope can be alteredto make a site more suitable. For example, terracescan be constructed to either shorten the slope lengthto reduce erosion or grade for irrigation. Following isa listing of major soil properties that affect a soil’sbehavior for a number of specific uses:

Available water capacity

The available water capacity is an estimate of howmuch water a soil can hold and release for use byplants, measured in inches of water per inch of soil. It isinfluenced by soil texture, content of rock fragments,depth to a root-restrictive layer, organic matter, andcompaction. This information is used in schedulingirrigation. The size and strength of soil structure caninfluence the availability and the rate of water releasedto plant roots.

Bedrock and other restrictive layers

There are 18 kinds of restrictive layers recognized insoil surveys. Examples are cemented pans, permafrost,dense layers, layers with excessive sodium or salts, andbedrock.

Bedrock is the solid rock under the soil and parentmaterial (plate 9). Sometimes it is exposed at thesurface, and is referred to as rock outcrop. The depthfrom the soil surface to bedrock influences the soil’spotential for plant growth and agronomic practices. Softbedrock indicates that the material can be ripped. Ashallow depth to bedrock results in a lower availablewater capacity and thus drier conditions for plants. Italso restricts the rooting depth.

Five depth classes are defined for use in soil surveys(table 1).

Soil Survey InformationSections 4 through 7 describe the agronomic soil information published in soil surveys, or contained in the NaturalResources Conservation Service, Field Office Technical Guide.

Table 1.—Depth classes

Very shallow ................................. Less than 10 inchesShallow ......................................... 10 to 20 inchesModerately deep ........................... 20 to 40 inchesDeep ............................................. 40 to 60 inchesVery deep ..................................... More than 60 inches

Calcium carbonate

Calcium carbonate (CaCO3) influences the availabilityof plant nutrients, such as phosphorus and molybde-num. Iron, boron, zinc, and manganese deficienciesare common in plants grown in soils that havesignificant levels of calcium carbonate equivalent. Soiltexture influences the levels at which these deficienciescommonly occur. Sensitive crops may show deficiencieseven at low levels (0.5 to 2.0 percent).

Cation-exchange capacity (CEC)

Cation-exchange capacity is a measure of the ability ofa soil to hold and exchange cations. It is one of themost important chemical properties in soil and is usuallyclosely related to soil fertility. A few plant nutrient cationsthat are part of CEC include calcium, magnesium,potassium, iron, and ammonium.

Generally, as CEC levels decrease, more frequent andsmaller applications of fertilizers are desirable. Smallerapplications of fertilizer applied to soils that have lowCEC levels may reduce fertilizer loss to surface andground waters, lessening the impact on water quality.

Drainage class (natural)

The drainage class refers to the frequency and durationof periods of saturation or partial saturation during soilformation. Seven classes of natural drainage are usedin soil surveys. They range from excessively drained tovery poorly drained (plate 3).

Erosion factor (K)

The soil erodibility factor (Kf and Kw) is a relative indexof the susceptibility of bare, cultivated soil to particledetachment and removal and transport by rainfall. It

8

may be computed from soil composition, saturatedhydraulic conductivity, and structure. K values rangefrom 0.02 to 0.64 or more. Higher values indicategreater susceptibility. Soil that has more silt and veryfine sand are generally more erosive because ofweaker bonding. K and Kw is adjusted downward for thepercent of rock fragments in each layer. Kf values arecalculated values that indicate a rock fragment free Kfor use in the Revised Universal Soil Loss Equation(RUSLE).

Erosion factor (T)

The T factor is the soil loss tolerance used in theRUSLE. It is defined as an estimated maximum rateof annual soil erosion that will permit crop productivityto be sustained economically and indefinitely. The fiveclasses of T factors range from 1 ton per acre peryear for very shallow soil to 5 tons per acre per yearfor very deep soil that can more easily sustainproductivity.

Flooding

Inundation by overflowing streams (plate 17) orrunoff from nearby slopes may damage crops ordelay their planting and harvesting. Scouring canremove favorable soil material. Deposition of soilmaterial can be beneficial or detrimental. Soilstratification (plate 13) is an indication of depositionby flooding. Long periods of flooding reduce cropyields. Table 2 gives the frequency and durationclasses used in soil surveys.

Table 2.—Flooding frequency and duration classes

Flooding frequency classesNone ...................Near 0 times in 100 yearsRare ....................Near 0 to 5 times in 100 yearsOccasional ..........5 to 50 times in 100 yearsFrequent ..............More than 50 times in 100 years

Flooding duration classesVery brief .............Less than 2 daysBrief ....................2 to 7 daysLong ....................7 days to 1 monthVery long .............More than 1 month

Frost potential

Potential frost action is the likelihood of upward orlateral movement of soil by formation of ice lenses.Estimates are made from soil temperature, particle size,and soil water states. Frost can break compact andclayey layers into more granular forms. It can also breaklarge clay aggregates into smaller aggregates that aremore easily transported by wind. Frost heaving canharm conservation structures if improperly designedand destroy taprooted perennial crops.

High water table

Seasonal high water table is the highest average depthof free water during the wettest season. The groundwater level, or water table, may be high year round orjust during heavy rains. How high the water table risesand how long it stays there affect what can be done onthat soil. A soil that is ponded is indicated in the soilsurvey with a plus (+). A perched water table usuallyoccurs because of the presence of a dense layer, suchas a hardpan, claypan, or other dense layer that retardsdeeper water penetration.

Organic matter

Organic matter is estimated for each layer. One percentorganic matter is equivalent to 0.6 organic carbon. Itencourages granulation and good tilth, increasesporosity, lowers bulk density, promotes water infiltration,reduces plasticity and cohesion and increases availablewater capacity. It has a high cation adsorption capacityand its decomposition releases nitrogen, phosphorus,and sulfur.

Permeability

Permeability is saturated hydraulic conductivity.Saturated hydraulic conductivity is influenced bytexture, structure, bulk density, and large pores. Soilstructure influences the rate of water movementthrough saturated soil, in part, by the size and shapeof pores. Granular structure readily permits downwardwater movement, whereas a platy structure requireswater to flow over a much longer and slower path(fig. 4). Permeability is used in drainage design,irrigation scheduling, and many conservationpractices. Permeability classes are shown in table 3.

9

Table 3.—Permeability classes

Class Rate (in/hr)

Impermeable ............................................. <0.0015Very slow............................................. 0.0015-0.06Slow .......................................................... 0.06-0.2Moderately slow .......................................... 0.2-0.6Moderate ..................................................... 0.6-2.0Moderately rapid ......................................... 2.0-6.0Rapid ............................................................ 6.0-20Very rapid ......................................................... >20

Reaction

Soil pH is an expression of the degree of acidity oralkalinity of a soil. It influences plant nutrient availability.A very acid soil (pH <5.0) typically has lower levelsof nitrogen, phosphorus, calcium, and magnesiumavailable for plants, and higher levels of availability foraluminum, iron, and boron than a neutral soil at pH 7.0.At the other extreme, if the pH is too high, availabilityof iron, manganese, copper, zinc, and especiallyphosphorus and boron may be low. A pH above 8.3may indicate a significant level of exchangeable sodium.

Rock fragments

The size and percentage of rock fragments in the soilare important to land use. Rock fragments within soil

layers reduce the amount of water available for plantuse and may restrict some tillage operations. Particleslarger than 2 millimeters in diameter are called rockfragments. Those that are 2 millimeters to 3 inches arepebbles or gravel, 3 to 10 inches are cobbles, and morethan 10 inches are stones or boulders.

Root restrictive layers

Some soils have layers that roots and water cannoteasily penetrate. Physical root restriction may beexpected in hard or soft bedrock (plate 9) and some soillayers, such as a fragipan or cemented hardpan.Intensive management may be required to reduce theeffects of poor rooting depth, a high water table, andlower available water capacity.

Some restrictive layers, such as a cemented hardpanare ripped to improve deeper root and water penetra-tion. Physical root restrictions for many other layersusually are not improved. For example, a change fromsome other particle size to sand, gravel, cobbles, stonesor boulders may indicate a zone of root restriction thatare not improved.

In general, resistance to root penetration is high with thefollowing combinations of texture and bulk density if thesoil layer is massive, or the structure is weak or platy(table 4).

Figure 4.—Water movement through granular, prismatic, subangular blocky, and platy soils, respectively.

10

Table 4.—Bulk density - root restriction guide

AverageTexture bulk density

Coarse sand, sand, loamy coarse sand,loamy sand, fine sand, loamy fine sand ............... >1.85

Very fine sand, loamy very fine sand, finesandy loam, coarse sandy loam, very finesandy loam, sandy loam, loam that has anaverage of <18 percent clay ................................. >1.8

Loam, sandy clay loam, clay loam that hasan average of 18 to 35 percent clay ..................... >1.7

Silt, silt loam, silty clay loam that has anaverage of <35 percent clay ................................. >1.6

Clay loam, sandy clay, clay, silty clay loam,silty clay that has an average of 35 to 59percent clay (> 30 percent in Vertisols) ................ >1.5

Clay that has an average of >60 percentclay, except in Vertisols ......................................... >1.35

Salinity

Salts, mainly sodium, magnesium, calcium, and chlorideor sulfate, may interfere with the absorption of water byplants. They also create a nutrient imbalance in someplants. Soils that have more than 2 mmhos/cm ofelectrical conductivity in soil solution are consideredsaline (plate 13).

Sodium adsorption ratio (SAR)

SAR is a measure of the activities of sodium relative tocalcium and magnesium in the soil solution. Soil thathas an SAR value of as low as 6, where salinity is low,may have increased dispersion of clay, resulting inreduced aeration and permeability and increasedsusceptibility for erosion. Higher values may havesurface conditions that take on a puddled appearance.Amendments, such as gypsum (CaSO4), along withirrigation and drainage can improve the unfavorable soilcondition in many cases.

Slope

Slope is the gradient of the elevation change. A 10 footrise in 100 feet is a slope of 10 percent. Ranges of

slope assigned to map units represent practical breakson the landscape that are important for the use andmanagement of the area (fig. 5). Terraces, irrigation, andtillage practices are all considered. For example,terraces for erosion control are a concern in some areasthat have more than about 1 or 2 percent slope; thus aseparation of 0 to 2 percent and more than 2 percent forthe same kind of soil may be used in mapping. However,they are not site specific, and for conservation planning,site investigation is necessary to determine the slope.

Figure 5.—Slope diagram.

SlopingGently Sloping Nearly Level

100 ft 2–5 ft 100 ft 5–10 ft100 ft

SteepModerately

SteepStronglySloping

100 ft15–20 ft

100 ft

20 ft +

100 ft

0–2 ft

10–15 ft

Soil texture (USDA)

Texture is determined by the relative proportion of sand,silt, and clay (fig. 6). Figure 7 illustrates the relativesizes between the three major particles. Soils that aresandy tend to have low strength, greater susceptibility towind erosion, and less water available for plants thansoils of other textures. In addition, trenches and banksare highly susceptible to caving, which may pose asafety hazard (plate 17). Water may pipe throughterraces and other water impoundments.

Clayey soils have more available water than sandy soils.Generally, as clay and organic matter increase, soilshave higher cation-exchange capacity. Soils that havelarge amounts of clay will fix more phosphorus than thesame kind of soils that contain less clay. Clayey soilshigh in montmorillonite tend to have the greatestcapacity to shrink and swell (plates 5 and 18). Theyretain large quantities of water, which affects tillagepractices and can contribute to soil creep or landslidesin sloping areas. Montmorillonitic or other smectitic claysalso have strong adhesive properties that bond particlestogether.

Soils that are silty have a higher available water

11

Muck or peat is used in place of textural class names inorganic soils (plate 2). Muck is designated for welldecomposed organic soil, and peat for rawundecomposed material. The word “mucky” is used asan adjective to modify a textural class, such as “muckyloam.” Rock fragments are also used as an adjective tomodify a texture. Plate 9 shows a soil that is verycobbly.

Subsidence

Organic soils often subside when drained becauseof shrinkage from drying; loss of ground water,which physically floats the organic material; soilcompaction; and oxidation of the material. Thiscreates an uneven surface that can require periodicsurface smoothing or grading to maintain adequateirrigation systems.

Some mineral soils also subside because of loweringof ground water tables; removal of zones of solublesalts, such as gypsum or calcium carbonate throughleaching; or melting of ice lenses in frozen soils.

Wind erodibility group (WEG) and wind erodibilityindex (I)

WEG is a general grouping of soils with similarproperties affecting their resistance to soil blowing.Soil texture, size of soil aggregates, presence ofcarbonates, and the degree of decomposition inorganic soils are the major soil blowing criteria. Thegroups are numbered 1 through 8 with 1 representingsandy soils that are the most susceptible to winderosion (plate 19) and 8 for gravelly or wet soils that donot have a wind erosion problem. The wind erodibilityindex (I) is an estimate of soil loss in tons per acre peryear.

Figure 7.—The relative sizes of sand, silt, and clay.

Sand

Silt

Clay

capacity than those that are sandy. In the absence ofclay particles, silty soils have lower adhesive properties.Piping through terraces, levees and pond embankmentscan be a problem. Trenches may cave, particularly insaturated soils.

Figure 6.—Soil textural classes.

12

Plate 1. Somewhat excessively drainedColby soil formed in loess. Grayishbrown silt loam A horizon, 0 to 8 inchesthick; pale brown silt loam AC horizon, 8to 16 inches; and below 16 inches a palebrown silt loam C horizon. AridicUstorthent. Western Nebraska, easternColorado, Kansas, South Dakota, andWyoming. (Scale F in feet)

Plate 2. Poorly drained Cathro soil.Thick layers of organic materialdeveloped from a continuous high watertable identified as Oa and Oe horizons,0 to 37 inches. A (2Ab horizon) buriedlayer of black mineral materials that hasa loam texture 37 to 45 inches. TerricHaplosaprist. Northeast Minnesota,northern Wisconsin, northern Michiganand upper New England. (Scale F infeet)

Plate 3. Surface of very poorly drainedsoil that has numerous depressionalareas.

Plate 4. Moderately well drainedPawnee soil formed in till. It has an Ahorizon 0 to 14 inches, underlain by adark brown clay Bt horizon that hasprismatic structure 14 to 32 inches.White soft lime pockets at 53 inches.Aquertic Argiudoll. Nebraska, andnortheast Kansas. (Scale F in feet)

Plate 4.

Plate 3.

Plate 2.

Plate 1.

13

Plate 5. Well drained Ferris soil. Oliveclay A horizon, 0 to about 6 inches, andpale olive clay, 6 to 60 inches. Cracksfilled with surface soil material to 24inches. Chromic Udic Haplustert. Texasand Oklahoma. (Scale F in feet)

Plate 6. Well drained Wallace soilformed in sandy deposits on oldsand dunes, lake benches andoutwash plains. Dark grayish brownsand A horizon, 0 to about 2 inches;white, sand, E horizon, 2 to 10 inches;and dark reddish brown, brown, andyellowish brown B2hsm massive andcemented (ortstein) horizon, 10 to 26inches. The B2 horizon has illuvialconcentrations of organic matter,aluminum, and iron. Typic Durorthod.Northern Michigan and New York.(Scale F in feet)

Plate 7. Moderately well drained Exumsoil formed in loamy Coastal Plainsediments. Grayish brown A horizon, 0to 6 inches; light brownish gray Ehorizon, 6 to 10 inches; and thick,yellowish brown, very strongly acid, Bthorizons to a depth of 6 feet. AquicPaleudult. Maryland, North Carolina,South Carolina, and Virginia. (Scale infeet)

Plate 8. Poorly drained Felda soilformed in marine sands. Grayish brownand light gray E horizon, 5 to 24 inches.An irregular boundary is between the Eand Bt horizons at 24 inches. ArenicEndoaqualf. Florida.

Plate 8.

Plate 7.Plate 5.

Plate 6.

14

Plate 9. Well drained Hambright soilformed in amorphous material frombasic igneous rocks. Rock fragmentcontent is about 50 percent to the Crhorizon at 15 inches. Fractured basalt(R horizon) is at 19 inches. LithicHaploxeroll. California. (Scale in feet)

Plate 10. Well drained Clovis soilformed in deep loamy sediments onfans and plains of old alluvium. Theaccumulation of calcium carbonateincreases with depth beginning at a lightbrown loam Bk horizon at 10 inches.Ustic Calciargid. New Mexico, east-central Arizona, and southwest Utah.(Scale F in feet)

Plate 11. Well drained Olton soil formedin mixed alluvial and eolian material.Brown loam Ap horizon, 0 to 6 inches;reddish brown clay loam Bt horizon, 6 to32 inches; and below that whitishcalcium carbonate is present. AridicPaleustoll. Texas and New Mexico highplains. (Scale F in feet)

Plate 12. Well drained Brownfield soilformed in old eolian material. Lightbrown fine sand 0 to 30 inches, over ared and yellowish red sandy clay loam,30 to 60 inches. Arenic Aridic Paleustalf.New Mexico and Texas. (Scale F in feet)

Plate 9.

Plate 10.

Plate 11.

Plate 12.

15

Plate 13. Stratification of alluvialmaterial that has textures of finesandy loam and silt loam, 0 to 18inches, and an accumulation ofsoluble salts at a depth of 24 inchesin somewhat poorly drained Salmosoil. Cumulic Endoaquoll. SouthDakota and Nebraska. (Scale infeet)

Plate 14. Salinity-alkalinityproblem caused by poor internalsoil drainage. California.

Plate 15. Munsell soil color. Soilblock on left has gray reducedcolors. Block on right has reddishoxidized colors.

Plate 16. Moderately well drainedMattapex, wet phase soil formed inmarine sediments. Dark grayishbrown A horizon, 0 to 6 inches;brown BE horizon, 6 to 12 inches;yellowish brown, strongly acid, Bthorizon, 12 to 36 inches withcommon light brownish gray mottles21 to 36 inches. Below 36 inches isa C horizon. Aquic Hapludult.Maryland, Delaware, Virginia, andNew Jersey. (Scale in feet)

Plate 13. Plate 15.

Plate 14. Plate 16.

16

Plate 17. Flooding along theMissouri River.

Plate 18. Deep wide cracks arecommon during dry periods inVertisols. Maxwell soils. TypicHaploxerert. California.

Plate 19. Evidence of erosion ona sandy textured soil partiallyprotected by surface gravel.

Plate 17.

Plate 18.

Plate 19.

17

Section 5: Management interpretations

Soil surveys commonly identify the more impor-tant soil characteristics that determine thelimitations and qualities of soil for farming.

Interpretations for farming include soil productivity,placement of the soil in management groups, andpresentation and evaluation of a number of soilproperties affecting use. The interpretations aredesigned to warn of possible soil-related hazards in anarea. Table 5 displays important soil propertyinformation related to agronomic interpretations. Thefollowing discussion includes some of the majoragricultural interpretations.

Soil productivity

Productivity of the soil is the output or yield per acre ofa specified crop or pasture under a defined set ofmanagement practices. If the land is irrigated, yields areprovided for irrigated and nonirrigated conditions.Management practices are usually defined for eachclass.

A “high” level of management provides necessarydrainage, erosion control, protection from flooding,proper planting rates, suitable high yielding varieties,appropriate and timely tillage, and control of weeds,plant diseases and harmful insects. This managementmethod also includes favorable pH and levels ofnitrogen, phosphorus, potassium and trace elements;appropriate use of crop residue, barnyard manure, andgreen manure crops; and harvesting methods that incurlow loss. For irrigated crops the irrigation system isadapted to the soil and crops, and good quality irrigationwater is uniformly applied as needed.

Irrigation

For most crops, the most favorable soils for irrigationare deep, nearly level, and well drained. They havegood surface soil permeability and a high availablewater capacity. Important considerations for the designof irrigation systems are feasible water application rates,ease of land leveling and its affect on the soil, erosionpotential, equipment limitations caused by steep slopesor rock fragments, and flooding.

Slope affects the performance of an irrigation system.Flood or furrow irrigation is mainly used on soils havingslopes of less than 3 percent. Wheel lines and centerpivots work well on slopes of up to 7 percent but withincreasing difficulty. Drip systems work well even onsteep slopes.

Most irrigated crops do well if the rooting depthexceeds about 40 inches. A shallower root zonelowers the available water, thus requiring more care incrop management and irrigation. Shallow soils, sandysoils, or soils that have rock fragments require morefrequent irrigation than deep and finer textured soils.Frequent light irrigations on fine textured soils preventscracking which reduces the evaporative loss of water(plate 17).

Chemical characteristics can be important. Salinity isparticularly a problem where drainage conditions areunfavorable for the removal of soluble salts by flushing.In areas that have only small differences in slope andelevation, salt-laden water can lead to accumulation ofsalinity-alkalinity in low places (plate 14).

Drainage

Drainage is the removal of excess water from soil.Determinations of soil that meets “hydric soil” criterianeed to be made to avoid draining wetlands.

Soils that have intermediate saturated hydraulic con-ductivity (permeability) respond well to subsurfacedrainage, open ditches, or a combination of these. Inareas that have large amounts of excess water, drain-age can be improved by smoothing or shaping thesurface of the soil. This increases runoff and reducesthe amount of water to be disposed of by internal watermovement.

Stoniness, slope, silty soil low in clay, and the presenceof physical soil barriers affects installation and function-ing of the drainage system. Caution is needed in areasof unstable soils. Silty soil material low in clay tends tomove into and clog subsurface drains that have inad-equate filter protection. Coarse textured soils areunstable and may be droughty after drainage. Somewet soils have sulfides that oxidize on exposure to air,causing extreme acidity after drainage. Drainage waterhigh in anaerobic iron may precipitate a “slime” thatplugs drainage lines. Wet organic soils subside afterdrainage.

The effective rooting depth is an indicator of the depththat soils can be drained. In deep soils without root-restrictive layers, depth is not a limitation. If a massiveclayey layer or other root-restrictive layer is in the soil,then effective drainage is more difficult.

18

Erosion control practices

The need for erosion control practices depends onthe potential for erosion and the cultivars grown.Some crops, such as hay and pasture, protect againstsoil erosion. For others, such as row crops, specificmanagement practices are needed. The practices to beused should be selected only after onsite soil inspection.Sometimes adequate erosion control can be achievedby simple application of one of the general practices. Inother cases, two or three different practices may beneeded. In addition to using cover crops, strip cropping,conservation tillage, terraces and diversions, andgrassed waterways, other measures may beappropriate.

Other management interpretations

Some soil surveys, or addenda to the surveys,have special tables on important agronomic soilinterpretations. A few tables may be in the form of a

soil’s potential for a specified use, such as its potentialfor cropland. Table 5 shows the soil property informationthat influences the behavior of a soil for agronomicuse.

Other tables group soils for specific programs, such asprime or unique farmland, land capability classification,highly erodible lands, and hydric soils.

Hydric soils are wet soils defined as a group for thepurpose of implementation of legislation for preservingwetlands and for assessing the potential habitat forwildlife. The soils considered to be hydric were selectedon the basis of flooding, water table, and drainage classcriteria. Hydric soils developed under wet conditions(anaerobic within 12 inches) and can support the growthand regeneration of hydrophytic vegetation(plates 2 and 8).

Soil Properties

Agronomic Organic Flooding Texture Bedrock pH Subsid- Cation- CaCO3

Slpoe Bulk Preme- Frost Available Salinity – Water Wind Erosion

Use matter or pan ence exchange density ability Potential water alkalinity table erosion factors

Capacity group K–T

Tillagesuitability

Plantadaptability

Erodibility— wind— water

Irrigation

Drainage

Crop yieldproductivity

Conserva-tionpractices

Land usecapability

Table 5.—Soil survey information that influences agronomic use

Indictes the soil properties listed in the soil interpretations data base that affect selected agronomic concerns.

19

The hydric soils list, developed for the 1982 Farm Bill, isincluded in the Natural Resources Conservation ServiceField Office Technical Guide, Section II. Some mapunits that have inclusions of soils that meet the hydricsoil criteria are added to the field office listing.

Highly erodible soil and potentially highly erodiblesoil are also listed in Section II of the NaturalResources Conservation Service Field Office TechnicalGuide. The criteria used to group highly erodible soilswere formulated using the Universal Soil Loss Equationand the wind erosion equation. The criteria are in theNational Food Security Act Manual. Soil use, includingtillage practices, is not a consideration.

Areas defined as highly erodible can be held to anacceptable level of erosion by following approvedpractices in a conservation plan. Various conservationpractices, such as residue management, reseeding tograsses, contour farming, and terraces, are used inconservation planning to reduce soil loss, maintainproductivity, and improve water quality.

Land capability classes and, in most cases,subclasses are assigned to each soil. They suggestthe suitability of the soil for field crops or pasture andprovide a general indication of the need forconservation treatment and management. Capabilityclasses are designated by either Arabic or Romannumerals (I through VIII), which representprogressively greater limitations and narrower choicesfor practical land use. Capability subclasses are notedwith an e, w, s, or c following the capability class; forexample, IIe. The “e” indicates that the soil is erosive.A “w” signifies a wetness limitation. An “s” denotes ashallow, droughty, or stony soil. A “c” indicates aclimatic limitation. No subclasses are shown forcapability class I because these soils have fewlimitations. Figure 8 illustrates some of the capabilityclasses on a landscape.

Prime farmland soils are listed by map unit name inthe tables or the “Prime Farmland” section of the soilsurvey. These soils have the best combination ofphysical and chemical characteristics for producing

Figure 8.—Landscape with land capability classes outlined.

20

food, feed, forage, fiber, and oilseed crops. Uniquefarmland is land other than prime farmland that isused for the production of specific high-value crops,

such as citrus, tree nuts, olives, cranberries, fruit, andvegetables.

21

Section 6: General soil information

The general soil map is near the back of the soilsurvey publication. This generalized map of thesoils for the soil survey area is color coded to

show major soil associations (or groupings) of the majorsoils. Soils within a soil association may vary greatly inslope, depth, drainage, and other characteristics thataffect management. Descriptions of each of the soilassociations are near the front of the soil survey reportimmediately following the short introductions to culturaland natural features of the area. This section is labeled“General soil map units” in the Contents.

The general soil map can be used to compare thesuitability of large areas for general land uses.Because of the scale, it is not intended to be used tomake management decisions on specific sites. Eachcolor-coded area on the map has a corresponding

description. For example, on the general soil mapillustrated by figure 10, areas coded 1 and shaded lightyellow designate the Lamoni-Shelby soil association. Asthe name of the unit implies, Lamoni and Shelby soilsare the major soils that occupy the landscape in thisarea. Likewise, the description of association 1 givesgeneral information about this section of the county.

Some soil surveys include three-dimensional drawingsdepicting the relationships of soils, parent material,and landscape position for the major soils. Figure 9illustrates the dominant Lamoni and Shelby soils andthe minor Colo soils as they occur in association 1. Notethe relationship of parent material and landscapepositions to the different soils. Please refer to Section 2“How is soil formed?” and to figure 3 for additionalinsights on these relationships.

Figure 9.—Relationship of soils, topography, and underlying material in the Lamoni-Shelby-Colo soils.

Sharpsburg

LamoniShelby

Colo

Shelby

ALLUVIUM GLACIAL TILL

Shelby

Grundy

LOESS

Lamoni

Lamoni

22

Each area outlined on this map consists of more than one kindof soil. The map is thus meant for general planning rather thana basis for decisions on the use of specific tracts.

24

3

169

169

R. 31 W.

R. 32 W.

R. 33 W. R.30 W.

T.

61

N.

T.

62

N.

T.

63

N.

T.

64

N.

LimpsCommunity

LakeKing City Creek

Willow

Owl Cr

Hic

kory

Cre

ek

Jolly Cr

Berlin

Th

ird

Fork

Ford City

Gentryville

Cam

pbel

l

Cre

ek

Grand

River

McFall

Bru

shy

Cre

ek

Sam

pson

Cre

ek

Jack

s B

r

Town

BranchWeldon

Branch

Creek

Run

Panther

Chalk

Run

Gra

nd

Riv

er Big Muddy CreekDaw

son

Bra

nchC

reek

Pedd

ler

Gentry

Mid

dle

For

kLinn

Creek

Chapm

anB

ranc

h

Fork

West

Zounds Creek

AlantusGrove

Indi

an

Cre

ek Bear

Creek

Moccasin

Creek

Wildcat

Creek

Stanberry

Cre

ekIs

land

Walnut

Fork

Long

Bra

nch

Still

hous

e

Branch

BURLINGTON

NO

RTH

ERN

NORFOLK

WESTERN

Jones

BranchDarlington

RAILWAY

Thompson Br

ALBANY

136

136 169136

169

169

AA

ZZ

H

A

T

EET

A

EEP

P

C

J

C

C

OO

B

B

O

AF

B

F

E

MMAA

V

BBP

UU

V

H

H

85

48Z

U

CO

UN

TY

NO

DA

WA

YC

OU

NT

YA

ND

RE

W

DEKALB COUNTY

DA

VIE

SS

CO

UN

TY

HA

RR

ISO

NC

OU

NT

Y

40° 20'

40° 10'

94

° 2

0'

94

° 3

0'

4

4

21

3

1

1

3

1

3636 311

1

1

1

121

36 3113

11

3136

3

2

1 1

2

1 63136

1

4

3 4

4

3

3

1

1

3

1 636 31

2

1 3

31

3

2

44

3

4

1

1

3

3

2

2

4 1 6 3

4

44

13

43

3

23

4

4

3

3

1

1311 6

1

3

361

1

4

11

36

1

1

3

3

3

1 4

3

21

4

3

3

31

4

4

31361 6

1 4

2

31 6

21

4

4

42

2

4

1

361

1 6

4

4

1

4

3

3

1 61

43

2

31

3

23

Figure 10.—General Soil Map

4

3

2

1

GRUNDY association: Deep, gently sloping and moderatelysloping, somewhat poorly drained soils that formed loess;on uplands

Legend

LAGMONI-SHELBY association: Deep, moderately slopingto moderately steep, somewhat poorly drained and moderately well drained soils that formed in glacial till; on uplands

NODAWAY-ZOOK association: Deep, nearly level, moderately well drained and poorly drained soils that formed in alluvium; on flood plains

GARA-ARMSTRONG-VANMETER association: Deep and moderately deep, moderately sloping to very steep, moder-ately well drained and somewhat poorly drained soils thatformed in glacial till or residuum of shale; on uplands

Compiled 1983

U.S. Department of AgricultureNatural Resources Conservation ServiceMissouri Agricultural Experiment Station

GENERAL SOIL MAPGENTRY COUNTY

MISSOURI

Sale 1:190,0801 0 1 2 3 Miles

1 0 3 6

6 5 4 3 2 1

121110987

18 17 16 15 14 13

242322212019

30 29 28 27 26 25

31 32 33 34 35 36

SECTIONALIZEDTOWNSHIP

Km

24

Section 7: Detailed soil information

To obtain information about a particular plot of landfrom a soil survey, locate the general area on the“Index to Map Sheets,” and select the appropriate

map sheet number. The sheets are in numerical order inthe soil survey. After selecting the correct sheet, aspecific parcel of land is located on the aerial map byusing section numbers, roads, streams and drainageways, towns, or the imagery on the map sheet. Areas onthe aerial photograph are delineated for individual soilmap units and each contains a unique map unit symbol.

The symbols on the detailed maps are listed on theback of the “Index to Map Sheets” with the names ofeach soil they represent. Some soil names includeterms for the surface texture, slope range, and erosion.Detailed information can be obtained about each unit byreferring to the map unit description or soil interpretivetables. Each unit is easily located by using the Index toMap Units or Summary of Tables in the front of the

publication. Both the map unit descriptions and soilsurvey interpretive tables have information about thesoils.

In each map unit description, soil information is given forthe common uses. Major limitations or hazards affectingthese uses are stated. Also listed are possible alterna-tives to help overcome each major limitation or hazard.

Areas delineated on the soil maps are not necessarilymade up of just one soil, but include smaller areas ofsimilar or different soils. The composition of soils in themap unit is explained in each map unit description.

Soil surveys provide sufficient information for thedevelopment of resource plans, but onsite investigationis needed to plan intensive uses in small areas. Someuseful information is not published, but it is contained insection II of the NRCS Field Office Technical Guide.

25

Section 8: Location of soil properties and interpretations

Specific soil properties or interpretations are sometimes difficult to locate within a soil survey. Following is aready reference of commonly sought after items for agronomic use. Some of the data elements were notcollected during earlier surveys and are not in the published soil survey. In addition, some information may

not be included in recent soil surveys because it simply was not needed. For example, some soil surveys do nothave information about salinity because saline soils were not mapped.

Immediately following the listing of items is a code indicating the location of that item. The location codescorrespond to a listing in the box at right.

Soil Survey Report

Sections1

A. General soil map unit descriptionsB. Detailed soil map unit descriptions

(nontechnical soil descriptions)C. Use and management of the soils

(crops and pasture)D. Soil series and their morphology

(technical soil descriptions)

Tables1

1. Temperature and precipitation 2. Freeze dates in spring and fall 3. Growing season 4. Acreage and proportionate extent of the soils 5. Land capability classes and yields per acre of

crops and pasture 6. Capability classes and subclasses 7. Woodland management and productivity 8. Windbreak and environmental plantings 9. Recreational development10. Wildlife habitat11. Building site development12. Sanitary facilities13. Construction materials14. Water management15. Engineering index properties16. Physical and chemical properties of the soils17. Soil and water features18. Classification of the soils

Soil propertiesAvailable water capacity — B, 16Bedrock or layer depth — B, D, 14, 16, 17Bulk density — B, 16Calcium carbonate (CaCO3) — B, D, 16Cation exchange capacity (CEC) — 16Cemented pan — B, D, 17Clay — B, D, 16Drainage class — A, B, DErosion factors (K),(T) — 16Flooding — B, 17Landscape position — A, B, DOrganic matter — B, D, 16Permeability — B, 16Potential frost action — 17Rock fragments — B, 15Salinity, alkalinity (SAR) — B, D, 16Soil reaction (pH) —B, 17Soil texture (USDA) — A, B, D, 15Subsidence — B, 17Water table — B, 17Wind erodibility group (WEG) — 16Wind erodibility index (I) — 16

Soil interpretationsAdapted trees — C, 7, 8Capability classification — B, 5, 6Drainage — C, 14Grassed waterways — 14Highly erodible land — *Hydric soil list — *Irrigation — C, 14Predicted yields — C, 5Terraces and diversions — 14Topsoil — 13

* Field Office Technical Guide, Section II, contains soil and siteinformation.

1 All sections and tables can be located in the Contents, Index toMap Units, or Summary of Tables in the front of published soilsurveys.

Location of informationSection 8 describes where soil information can be located.

26

References

Huddleston, J. Herbert, and Gerald F. King. 1984.Manual for Judging Oregon Soils. Oregon StateUniversity Extension Service, Extension Manual 6.

Scrivner, C.L., and J.C. Baker. 1975. EvaluatingMissouri Soils. Circular 915, Extension Division,University of Missouri-Columbia.

Smith, C.W. 1989. The Fertility Capability ClassificationSystem (FCC): A Technical Classification SystemRelating Pedon Characterization Data to InherentFertility Characteristics. Doctoral Thesis. Dept. ofSoil Science, North Carolina State University,Raleigh, North Carolina.

United States Department of Agriculture. 1993.Soil Survey Manual. Soil ConservationService.

United States Department of Agriculture.National Soil Survey Handbook.Natural Resources ConservationService.

United States Department of Agriculture. 1988.From the Ground Down: An Introduction toSoil Surveys. Soil Conservation Service.Columbia, Missouri.