Soil Surveys and You

SOIL SURVEYS AND YOU

Objectives:

1. Students will identify sources of information about local soil types.

2. Students will identify soil types on a soil survey map.

3. Students will locate information to determine whether a given soil type is suitable

for a specific land use.

Background Information:

There are several thousand soil types in the United Sates. Each soil type has unique physical and chemical properties. Soil only a few feet apart may have very different properties. These properties determine whether the soil is suitable for a specific land use.

How can we find out if the area we plan to use is suitable for the use we have planned? The Soil Conservation Service has surveyed and mapped the soil types on nearly 2 billion acres of land. Surveying and mapping will continue until all areas in the United States are mapped. About 50 million acres are mapped each year. When a map has been published, it is available through the local Soil Conservation Service office.

The information contained in soil surveys can tell engineers, developers, builders, home buyers, and planning commissions

if the location of bedrock will increase the cost of excavation.
if the soil can properly filter waste from a septic system.
if special foundations are needed to prevent cracking.
if erosion may damage a pipeline, road, or foundation.
if the pipe is likely to be damaged by corrosion.
if a site is a good source of sand or gravel.
if flooding will be a hazard.

The soil scientists responsible for the surveys have walked many miles and dug many holes. In addition to the soil profile, they observed the slope of the land, the size of the streams, the type of rocks, the type of native plants, and the crops planted at each site. The soils were studied at the site and sometimes sent to the lab for further testing.

When the soil type was identified, it was given the name that had been assigned to other soils with similar properties. This group of soils is called a series, and the series is usually named for a town or geographic feature where the soil was first seen.

The soil survey maps show the location of each type of soil in the area surveyed. On the map, the soils are identified by two letters of their name and a third letter that describes the slope. A capital letter is always used to refer to the slope. The absence of a letter indicates the land is nearly level. Letters are used as follows:

BeB - 0-8%MaB - 2-8%OxB - 0-4%WyA - 0-3%

BeC - 8-25%MaC - 8-15%OxC - 8-25%WyB - 3-8%

BeF - 25-70%LbB - 0-8%WpB - 0-8%WyC - 8-15%

LbC - 8-25%WpC - 8-25%WyD - 15-25%

WyE - 25-70

INVESTIGATION 3.3 – REPORT SOIL SURVEYS AND YOU

Review Questions:

1. What factors make a soil type suitable for a specific land use?

______

2. You were just informed that you inherited 5 acres of land and a large amount of

money. You have decided that you would like to build condominiums on the land.

Where can you find information that would tell you if the soil is suitable for what you

have planned?

______

3. What information can you find in the soil survey that will help you decide if you

should go ahead with your plans?

______

4. Briefly describe how soil surveys were made.

______

5. Some of the soil types have rather strange names such as Lackawanna and Oquaga.

Why did soil scientists use these names?

______

6. What do the letters that follow a soil sample (A, B, C, D, and E) tell you about the

soil?

______

7. Why is it a good idea to refer to the soil survey before making detailed plans for a

specific land site?

______

DATA ANALYSIS

Indicate soil types by using the two letter symbols. If slope is a factor, include the letter that describes the slope.

Table 3.3-1

______1. Identify the soil type(s) which has bedrock less than 2 feet from the

surface and often has rock exposed.

______2. Which additional soil type(s) has bedrock near the surface?

______3. Which soil types are mostly peat?

______4. Identify the soil type(s) with topsoil that is silt loam with less than 10%

rock fragments.

______5. Identify two soil types where stones would likely cause problems.

______6. Which soil type(s) might be called "gravel soil?"

______7. Which soil type(s) have the deepest soil?

______8. Which of the following terms describes soils with the smallest rock

fragments - channery, gravel, or stony soils?

Table 3.3-2

______1. Identify the soil type(s) that would require blasting to excavate for a

house with a basement.

______2. Identify the soil type(s) where flooding would be a problem.

______3. What percent (%) slope creates a moderate problem on Mardin soils?

(See back of first page)

______4. What type of limitation is created when a slope is greater than 25%?

______5. Which soil type(s) is most favorable for a home with a basement?

______6. Homes built on soil with a high shrink-swell potential can move several

inches up and down as the soils expand and contract. Which type of soil

type would require homes to be built with a specially designed

foundation to prevent cracking?

______7. Which soil type(s) is most suitable for a septic tank absorption field?

______8. Subsurface septic absorption fields require a minimum soil depth of 60

inches. Which soil(s) are not suitable because of limited depth?

(Also refer to Table 3.3-1)

______9. For subsurface septic systems to be approved, the percolation rate must

be between 6 and 90 minutes per inch. Which soil types may not have

an approved percolation rate?

Table 3.3-3

______1. Which soil(s) has the greatest potential for growing corn?

______2. If you want to buy land that is suitable for farming, but you do not want

the land flooded during the growing season, what soil type(s) would you

look for? (For flooding information see "camping" column.)

______3. In addition to flooding, what is another problem that makes soil types

unsuitable for farming?

______4. What soil type(s) is favorable for digging a pond?

______5. A landowner insists on digging a pond on Oquaga soil. What will be

the approximate depth of the pond? (See Table 3.3-1)

______6. What is another problem that makes land unsuitable for a pond or at

least increase the cost of digging a pond?

______7. As a real estate person, what type(s) of soil would you look for if a

customer wanted to buy land for a campground?

______8. What soil type(s) would you expect to find at a site that has good

wetland habitat?

Soil Survey Maps

______1. Identify four soil types found along the Delaware River.

______2. Which of these soil type(s) are flat and easily flooded?

______3. Where is soil type Hy found?

______4. What is the most common soil type near Shawnee-on-the-Delaware?

______5. Assuming the island in the Delaware River is large enough, would it be

suitable for farming?

______6. If the island were for sale and money was not a problem, would you buy

it to build a summer home? Explain______

______7. Locate the areas of deep mucky peat (Mp) in the Cranberry Bog. What

soil type surrounds this area?

______8. What is the slope of the soil along Cranberry Creek?

______9. If you wanted to build a ski slope, would you choose the site * near

Shawnee-on-the-Delaware or the site near Cranberry Creek?

TABLE 3.3-1: SOIL PROPERTIES

Soil Symbol / USDA Texture Description / Depth in Inches / Rock Fragments (%) > 3 inches
Be ****
Benson-Rock Outcrop / Channery* silt loam
Shaly to very shaly silt loam
Unweathered bedrock / 0-8
8-18
18 / 15-20
5-50
------
Hy
Holly / Silt loam
Silt loam, loam, sandy loam, silty clay loam
Gravelly loam, gr silt loam, sandy loam / 0-8
8-41
41-60 / 0
0
0-5
Lb
Lackawanna / Extremely stony loam***
Ch loam, ch silt loam, ch sandy loam / 0-12
12-75 / 10-25
0-20
Ma
Mardin / Ch silt loam
Ch loam, ch silt loam, gravelly**loam
Ch loam, ch silt loam, very gr silt loam / 0-9
9-24
24-99 / 5-10
5-10
10-25
Ms,Mp
mucky peat-
shallow, deep / Mucky peat
Silty clay loam, silt loam, ch loam / 0-84
84-99 / 0
0
Ox
Oquaga part / Extremely stony loam
Ch loam, ch silt loam, very ch loam
Unweathered bedrock / 0-3
3-26
26 / 10-20
10-25
25
Po,Pp
Pope / Silt loam
Silt loam, fine sandy loam, gravelly sandy loam / 0-10
10-60 / 0-5
0-5
Wp
Wellsboro / Extremely stony loam
Gr loam, ch silt loam, loam
Ch loam, sandy loam, ch loam / 0-10
10-23
23-60 / 10-25
0-15
0-20
Wy
Wyoming / Gravelly sandy loam
Gr sandy loam, very gr sandy loam
Very gr sandy loam, very gr sand / 0-8
8-26
26-60 / 0-15
0-25
5-30

*Channery - soil that is more than 15% (by volume) thin, flat fragments of

sandstone, shale, limestone, or schist. Fragments may be as much as

6 inches long. (Ch)

**Gravel - rounded or angular fragments of rock up to 3 inches in diameter. (Gr)

***Stones - rock fragments 10-24 inches in diameter.

****Rock outcrop - bedrock that is exposed or has no soil covering.

Table 3.3-2: Limitations for Homesites

Soil symbol / Limitations for building w/ basement / Shrink-Swell Potential / Septic tank Absorption Fields
Be / Severe: (C, F) slope
depth to bedrock, large stones / low / Severe: (C, F) slope
depth to bedrock, large stones
Hy / Severe:
floods, wetness / low / Severe:
floods, wetness
Lb / Severe: (C) slope
large stones / low / Severe:
percolates slowly
Ma / Moderate: (C) slope
wetness / low / Severe:
percs slowly, wetness
Ms,Mp / Severe:
floods / high / Severe: floods, wetness, excess humus
Ox / Severe: (C) slope
large stones, depth to rock / low / Severe: (C) slope
large stones
depth to rock
Po,Pp / Severe:
floods / low / Severe: (C) slope
large stones
depth to rock
Wp / Severe: (C) slope
large stones / low / Severe: (C) slope
large stones
percolates slowly
Wy / Slight: (A,B) slope
Moderate: (C) slope
Severe: (D,E) slope / low / Slight: (A,B)
Moderate: (C)
slope, percs rapidly
Severe: (D, E)
slope, percs rapidly

Definitions: The terms listed below are used in the table that is above and on the next page. Refer back to these definitions as needed.

1. Slight limitation - soil properties are generally favorable for specified use; limitations

are minor and can be easily overcome.

2. Moderate limitation - soil properties and site features are unfavorable for the

specified use; limitations can be overcome or minimized by special planning and

design.

3. Severe limitations - one or more soil properties or site features are so unfavorable or

difficult to overcome that a major increase in construction effort, special design, or

intensive maintenance is required.

TABLE 3.3-3: LIMITATIONS FOR LAND USE

Soil symbol / Farming / Pond Area / Camping / Wetland
Be / Poor - slope, large stones, rock outcrops / depth to rock / Severe: (C, F)
slope / Poor (B)
Very Poor (C, F)
Hy / 100* / seepage / Severe: wetness, floods / Good
Lb / Poor - large stones / slope / Severe:
large stones / Very Poor
Ma / 85-90* / slope / Moderate:
percs slowly,
wetness,
small stones / Very Poor
Ms, Mp / Severe / seepage,
excess humus / Severe: floods,
excess humus,
wetness / Good
Ox / Poor - large stones / slope,
depth to rock,
seepage / Severe:
large stones / Very Poor
Po, Pp / 135* / seepage / Severe: floods / Very Poor
Wp / Poor - large stones / favorable slope / Severe:
stones, slope / Very Poor
Wy / 75-90* / seepage, slope / Moderate:(A,B)
small stones
Moderate: (C)
slope, small stones
Severe: (D, E)
slope / Very Poor

* Yield of corn in bushels per acre