{Physical Setting}{Methods}{Results}{Conclusions}{Future Study}{Aerial Photo}{Digital Elevation Map}
| Executive
Summary
The first
several weeks of the semester, our Soils class spent lab time at the
Hartnett site in southern Dunn County.
The Hartnett site landscape includes
a steeply sloping interface between the high, sandy glaciofluvial,
Wissota Terrace of the lower Chippewa River Valley (see Andrews
1965) and a narrow, deeply incised stream valley inset into the Wissota
Terrace. The low
order stream that flows through the property is a tributary to the
Chippewa River. The class was
divided into groups of three to four students, and each group was
assigned an area in which to dig a soil pit.
This website is a compilation of the results of that fieldwork
and additional research. The
purpose of this website is to present the results of our research to determine the
genesis of the soils in the study area, and to provide the landowner
with recommendations for suitable land uses based on the knowledge we
have gained about soils on his property.
Eight pits were
excavated. Pits were
excavated in representative landscape positions with respect to slope
aspect and position. This
allowed us to gain an understanding of how landscape position influences
soil development.
Each group of students studied the soil profiles exposed in their
pits and described and recorded their findings.
The pits were also photographed.
Information gathered in the field includes depth, color,
structure, consistence, boundary, and other phenomena present for each
master horizon. The soils
across the site are sandy and appear to be derived from glaciofluvial
outwash. Evidence that
the upland portion of this site was used for farming is found in the
pits located on level portions of the site (Ap
horizon, or plow zone). This
evidence is confirmed by current land-use in the surrounding area.
Elsewhere, on less level and poorly drained areas the site is wooded.
Climate, natural vegetation, and other soil forming factors are
fairly consistent across the study area.
The bedrock in
Dunn County consists of Pre-Cambrian crystalline rocks overlain by
Cambrian sedimentary units. The
sub-crop at the Hartnett site study specifically is the Cambrian-age Mount
Simon Sandstone Formation, a medium to coarse-grained
quartz-rich sandstone. This
bedrock unit is overlain by at least 10 meters of glaciofluvial outwash
of the Wissota Terrace in upland settings and les than two meters of
younger, sandy alluvium in lowland positions. Soils in the
lowland portions of the site are distinguishable from soils on the upland
and steeply sloping portions of the site. All
soils observed in pits (1, 6, and 7) located on steep slopes fit the Finchford
Series soil description, and correlate to the Hubbard series soils in
the most current edition of the Dunn County Soil Survey (the exact
map unit, HuA or HuB is dependent upon slope). Similarly, the pit located in the upland portion of the site,
currently mapped as Finchford Series, corresponds to the Hubbard Series
(HuA) in the Dunn County Soil Survey. There is more variation in the lowland soils, which are
consistent with the Scotah Series for pits 2 and 4, and the Finchford
Series for
pits 3 and 8. Pit 2 appears
most like the Plainbo Series and pit 4 is most similar to the Morocco
Series as described in the Dunn County Soil Survey.
Pits 3 and 8 are both similar to the Hubbard Series as described in the Dunn
County Soil Survey.
The most
significant factors in terms of land use are slope characteristics and a
seasonally high water table in the lower portion of the study area
(especially near
the stream). The sandy texture of these soils make the area
susceptible to wind and water erosion.
Thin autochthonous glacial outwash in the upland and sloping
portions of the study area already exhibit erosional characteristics. Consequently, soils in the lowland areas are thickened,
suggesting materials have eroded down from upslope and accumulated at
the bottom. Much can be
done with soils in the upland portion of the site.
The sloping portions of the area are more susceptible to erosion,
and should probably not be disturbed.
The lowland area also has many possibilities for land use, but
structures with basements should not be constructed because of shallow
bedrock and seasonally high
water table. If
construction is to occur on any portion of the study area, soil berms
should be in place, and vegetative buffers should be left.
Mitigation against future soil erosion is suggested for this study area. Soils in this area may be moderately fertile and suitable for cultivation, especially in the upland regions. Zero-tillage and contour plowing should be implemented if sustainable cultivation is to be performed. Soils in this area are best suited for “low impact” activities such as pasture or recreation areas. |
| Research
Goals/Objectives
Research Goal Our
goal is to be able to make recommendations for appropriate land uses based on the
soil morphology we observed at the Hartnett Site.
This site was selected for study for two reasons. First,
the
landowner graciously granted access permission to their property. Research
Objectives 1) Characterize the catenary relationship between soil profiles across the study site.
2) Determine factors that have contributed to soil genesis, using the descriptions of site profiles and existing map units. 3) Make interpretations about landscape history and evolution, using the CLORPT model and our understanding of catenary relationships. 4) Make recommendations for appropriate land uses by identifying limiting soil, geomorphic and climatic factors, and including specific recommendations for:
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