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Land Use Project: Soil Series Strom
Land Use Project: Soil Series Strom
Ryan Rambur, Josie Flerchinger, Mikaila Bristow, Phinehas Lampman
University of Idaho
December 6, 2014
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Land Use Project: Soil Series Strom
Introduction
Camas County is located in the southern portion of the state of Idaho, where agricultural and
grazing land is predominant. Analyzing a soil sample from this area and determining the land use
for it can be difficult; therefore it is necessary to evaluate all soil characteristics such as the
area’s climate and any changes within the area, such as industrialization, to determine the most
effective land use for the soil type. The soil sample is of the Strom series which consists of deep,
poorly drained soils that formed in mixed alluvium. Strom soils are on alluvial fans, low terraces
and bottomlands and have slopes of 0 to 4 percent (USDA-NRCS Staff, 2006). The mean annual
precipitation is about 14 inches and the mean annual air temperature is about 41°F. The mean
annual soil temperature is 40°F to 44°F, but in the summer it can increase to 65°F. It is slightly
acid or neutral on the surface soil and ranges to moderately alkaline in the sub soil. These soils
are saturated and have a temporary water table ranging from 24 to 50 inches during the winter,
spring, and early summer. In the top two layers of this soil (Ap1 and Ap2) the average acidity is
6.5 pH (USDA-NRCS Staff, 2006). Previously this soil was used for growing crops such as
wheat and potatoes, however irrigation was not used. Currently an alfalfa hay-grain-livestock
system dominates agriculture in this area. Alfalfa is the principal crop with spring wheat and
barley right behind it. Most livestock on this land are either sheep or cattle and many of them are
moved to lower elevations in the winter (Soil Survey Staff, 1981). This type of soil is typically
used for dry cropland, small areas are irrigated cropland and range. Vegetation is meadow
grasses and sedges. The drainage and permeability is somewhat poor with slow to medium
runoff. (USDA-NRCS Staff, 2006). In this report the analysis of a specific soil sample from
Camas County will be conducted and an ideal land use for the soil will be developed.
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Land Use Project: Soil Series Strom
Soil Properties
The soil sample given was of the Strom series classified as fine-loamy, mixed, superactive and
frigid Pachic Argixeroll. From Table 1, the horizons can be identified. The A horizons of the soil
have been plowed, suggesting that at one time this soil was used for agriculture. The Bt horizons
have a high clay content in them which can suggest high water retention, but also slow
movement of water. The Bk indicates that calcium carbonate is present in the soils. Finally, the C
horizons are gleyed and contain mottles which means that there is a high water table in this soil
stripping the oxides and dark parent material from the horizon and leaving the natural, muted
color of the minerals to show through (Brady&Weil, 2010). From horizon A to Bk, the textual
class of the soil is a loam excluding the Bt1 horizon, where the texture is a clay loam. The
texture of the C horizon is a fine sandy loam in Cg1 and a sandy loam in Cg2. Looking at the
rock fragments in Table 1, it can be seen that all values are under 7%, so this particular soil does
not have any problems with fragments greater than 2 mm. The deepest horizon is Bt1, which has
a COLE of 4.9%, which exceeds the limit of 3%. This means there is a limitation if this soil is to
be used for buildings being constructed on it. However, Table 1 also provides that the plant
available water (PAW) is greater than 10%, so there is not a limitation for vegetation to receive
water. There is a very large amount of montmorillonite in the Bt1 and Cg1 horizons of this soil
which suggest high shrink swell activity (NCSS, 1975). Looking at Table 2, the slope of the area
is 1%, but the drainage rate is classified as somewhat poorly. From Table 1, the bulk densities
are relatively high from which we can conclude that the soil has less pore space. Less pore space
means slower drainage rates, given in Table 2, and also little permeability. From this information
it can be concluded that in the event of precipitation, ponding can occur because of slow
drainage. In the event of heavy rainfall, flooding could occur because excessive water would
accumulate at the surface and not penetrate the soil.
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Land Use Project: Soil Series Strom
Table 1. Physical Properties*
Horizon
Depth
Bulk Density
g/cm3
Textural Class
COLE (%)
PAW
Rock
Fragments
>2 mm wt.
%
Ap1
0-15
Loam
1.40
0.025
0.17
3
Ap2
15-28
Loam
1.56
0.022
0.15
3
A
28-36
Loam
Bt1
36-64
Clay Loam
1.66
0.049
0.11
5
Bt2
64-84
Loam
1.76
0.044
0.12
6
Bk
84-104
Loam
Cg1
104-130
Fine sandy loam
1.65
0.012
0.18
Cg2
130-157
Sandy loam
1.66
0.008
0.19
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*Values obtained from the National Cooperative Soil Survey National Cooperative Soil Characterization Database
Table 2. Pedon Description*
Slope (%)
1.0
Elevation (m)
1524.0
Aspect (deg)
0.0
MAAT
MSAT
4.4
15.6
MAP
330.0
Drainage Class
Somewhat Poorly
*Values obtained from the National Cooperative Soil Survey National Cooperative Soil Characterization Database
From Table 3, the chemical properties of the soil can be evaluated. The pH of the overall soil is
around neutral (pH 7), but in the lower horizons the soil is slightly more basic. The cation
exchange for all horizons is greater than 10 cmol (+)/kg, which means that there are no fertility
issues or leaching concerns with this soil. The base saturation percentage seen in Table 3, is very
high in all horizons. This means that the soil has plenty of nonacid cations such as Calcium,
Magnesium and Potassium. These nonacid cations aid in the fertility and the reduction of acidity
in the soil (Brady&Weil, 2010). The exchangeable sodium percent in the soil horizons is below
the limit of 15% therefore this soil is classified as non-sodic.
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Land Use Project: Soil Series Strom
Table 3. Chemical Properties*
Horizon
pH
CEC cmol(+)/kg
Base Saturation (%)
Exchangeable Na (%)
Ap1
6.4
21.9
95
1
Ap2
6.6
22.5
94
1
A
7.3
20.5
100
1
Bt1
7.5
32.1
100
3
Bt2
8.1
26.1
5
Bk
8.1
21.4
7
Cg1
7.6
15
100
5
Cg2
7.5
11.2
100
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*Values obtained from the National Cooperative Soil Survey National Cooperative Soil Characterization Database
Land Uses
The slow permeability and drainage of this soil indicates that ponding and flooding could occur,
causing significant damage to all dwellings with basements in the area. The shallow depth to the
high water table (roughly 3 feet from the surface) also shows that considerable wetness would
occur around the foundation of the basement (NCSS, 1975). The expansion and contraction of
the soil due to shrink-swell activity places a moderate limitation on the soil because it would
cause weakening of the foundation and the dwelling would not be supported; therefore, the
Camas County soil is not suitable for dwellings with basements.
The soil has a great loam soil texture on the surface, which allows it to be classified as
not too sandy or clayey. Dust is also not an issue with this soil because of the loam soil texture
on the surface (NCSS, 1975). The rock fragment percentage the soil contains is low which makes
forming smooth paths and trails easy. The slope of this area is very low, making erosion not
much of a factor for paths or trails. There is however a moderate limitation with flooding and
ponding because of the slow drainage rate. Overall trails could easily be made with this soil and
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Land Use Project: Soil Series Strom
would have little dust, rocks or slimy clay. This soil however is classified as moderate for paths
and trails, because if the trails did have ponding or flooded, they would be deemed unusable for
that period of time.
The high PAW percentage and rooting depth declares this soil does not have issues with
drought or wetness for being considered as a conifer tree farm. The trees would be able to have
access to water and have plenty of room to anchor their roots. The frigid soil temperature also
provides an excellent environment for coniferous trees because they are able to flourish in frigid
soils (NCSS, 1975). The high montmorillonitic mineralogy contributes to the slow permeability
of the soil which makes the soil well suited for grazing. The loam texture, PAW, and depth to
high water table indicates this soil will not lose its surface soil and not cause stress on the plants
due to droughty conditions (NCSS, 1975). The high CEC also indicates that this soil is able to
provide proper nutrients for the plants. The slow permeability can lead to brief flooding which
can cause an emergence disability (NCSS, 1975). This is the only limitation for this soil as a
grazing land. To help this limitation it is important to plant species that are tolerant to wet
conditions, this will greatly reduce the impact on the seedbeds and make it so proper growth can
be established.
Table 4. Land Uses
Land Use
Rating
Limitation(s)
Dwellings with Basements
Severe
Flooding, Ponding,
Wetness, Shrink-Swell
Paths and Trails
Moderate Ponding, Flooding
Conifer Tree Farm
Good
Depth to water table,
Depth of rooting
Grazing
Good
Flooding
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Land Use Project: Soil Series Strom
Conclusion
This soil has the ability to be used for a variety of different land uses. Some of these would have
more limitations than others but there are a few that would work very well with this soil type.
The most apparent land uses would be either grazing or a conifer tree farm. This is not an ideal
place for paths and trails because of the ponding and flooding factor; in addition, it is a relatively
flat, open area, which does not provide much demand for trail activities. Dwellings with
basements are not a good use of this land because the soil would have to be modified greatly for
them. The most fitting land use for this soil type would be grazing. The only limitation would be
flooding but this can easily be overcome by planting species that are tolerant to wet conditions.
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Land Use Project: Soil Series Strom
Cites
Brady, Nyle C., Weil, Ray R. Elements of the Nature and Properties of Soils. Prentice Hall 2010.
NCSS, 1975. National Cooperative Soil Survey National Cooperative Soil Characterization
Database. http://ncsslabdatamart.sc.usda.gov. Web. Nov. 16, 2014.
Soil Survey Staff. Soil Survey of Camas County Area Idaho. NRCS. 1981
USDA-NRCS Staff, 2006. Official Soil Series Descriptions. USDA-NRCS Soil Survey Division.
https://soilseries.sc.egov.usda.gov/osdname.asp. Web. 16 Nov. 2014.