Soils in the Carleton
undergraduate liberal-arts
curriculum
Mary Savina
Department of Geology
Carleton College
Outline
• Students, liberal arts, and geology
• Geologic/Soils setting of Northfield
– labs and projects
– agriculture
• Geology Courses with soils content
• Evolution of “Geology of Soils” 1979-2001
• Comments, questions and discussion
The liberal-arts tradition
• Broad education in arts, literature, science,
humanities and social science
• Emphasis on broadly useful skills such as
writing, foreign language, research (library
and science)
• Little emphasis on practical applications
• No graduate programs, certificates, etc.
• (At Carleton) one degree = B. A.
Student profile
• Students from across the country
• Few students from rural backgrounds (most
suburban)
• Fewer students from agricultural backgrounds
• Strong student interest in sciences
Minnesota
Northfield is between the Twin Cities and Rochester
Soils and a Carleton sense of
place
• Rice County - “edge”
county, but still rural
• Most land cultivated
• Animal (dairy, hogs,
poultry, beef, etc.) and
crop (corn and
soybeans) agriculture
• Students resident for
four years
Carleton history of agriculture - 1
• Carleton dairy farm
1914-1964
• Two courses in ag.
science taught early on
(not popular)
• Farmhouse used as
student housing
(Natural History
house), 1971-present
• Organic garden 1990s
•
Carleton History of Agriculture 2
Renewed student interest in
environment, agriculture
starting in 1970s
• Courses now taught
include: Sustainable
Agriculture (Bio.), The
American Farm (Poli. Sci),
Agriculture and the
American Midwest (Eng.
and Geo.), Population and
Food in Global System
(SOAN), Geology of Soils
Geology at Carleton
• Courses taught since 1870s
• Department founded in 1933 by Laurence
McKinley Gould (glacial and Quaternary
geologist)
• Robert Ruhe, ‘42, Carleton graduate
• Average of 22 graduating seniors each year
since 1980
• Major requirements: 7 geology courses, 2
math courses, chemistry and physics
Minnesota
Eastern margin of Late Quaternary deposits passes
through Northfield.
Soils in Southeastern Minnesota
• Young soils (<14,000 yr. BP) on till and
outwash on campus and west (little profile
development)
• Older soils on loess + till east and south of
campus (few exposures)
• Prairie/Forest boundary
• Extensive wetlands
• Mollisols, Entisols, Alfisols, Histosols
• Cretaceous weathering (ultisols) in Mn. RV
Borderlands
• Forest and lakes in
recently glaciated
terrain
• Prairie on bedrock and
(much) older glacial
material
Factors of Soil Formation, SE
Minnesota
• Parent material (Quaternary deposits,
bedrock)
• Topography
• Vegetation (prairie, hardwood forest,
wetland)
• Climate and time - Cretaceous, Early and
Late Quaternary
• Human activity: agriculture, forest
clearance, urbanization, suburbanization
Geology courses with soils
content
• Introductory Geology (some versions)
• Introduction to Environmental Geology stand-alone or as part of Agriculture and the
American Midwest
• Geomorphology
• Oceans and Atmospheres
• Hydrology
• Geology of Soils
Soils on Geology dept. field trips
• Northern Michigan - spodosols, paleosols
• SE and central Missouri - residual, cherty
soils on limestone bedrock, paleosols
• Black Hills and Badlands, SD - sod table
soils, carbonate accumulations, paleosols
• Baraboo, Wisconsin; Northern Minnesota Quaternary deposits
My growing view of soils 19792001
• Soils as physical and mineralogical systems
• Soils as a subset of Quaternary geology and
geomorphology
• Soils as indicators of past climates and time
(paleoclimate and geochronologic
reconstructions)
• Soils as the boundary between the
lithosphere, atmosphere, hydrosphere and
biosphere: central to understanding global
change
Continuing education in soils
• Grad school - Soil Mechanics, Soil
Mineralogy and Behavior courses
• Students - esp. Robb Jacobson, Richard
Doyle
• Soils professionals on many field trips
• Pete Birkeland gets his own line
• Local soil resources people
Carleton - Geology of Soils
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Taught since 1979, about every 2-3 years
Enrollment range 12-36
Prerequisite: Introductory Geology
Meets requirements for Geology Major,
concentrations in Environmental and
Technology Studies (ENTS) and
Archaeology
Two versions of Geology of Soils
• Texts - Singer and
Munns: Soils +
• Text - Birkeland: Soils
Birkeland, et al., Soils.
and Geomorphology
. .Applied Quaternary
• Emphasis Geology (Utah GMS)
Weathering,
+ William Logan
pedogenesis, soils as
Bryant, Dirt: The
chronological markers,
Ecstatic Skin of the
soil mechanics
Earth
• Emphasis - Soils as a
biogeochemical
system
Geology of Soils: Purpose and
Questions
• Goal: understand soils as a complex
biogeochemical system
• Q1: What are the observable characteristics
of soils?
• Q2: How do soils get to be this way?
• Q3: Why are these characteristics important
(for Quaternary geologists, environmental
scientists, archaeologists)?
Geology of Soils - Class Projects
• Soils mapping (and profile description) of
parent material/topo sequence of Carleton
Arboretum
• Use outcrops of Precambrian and
Cretaceous of MN River Valley to repeat
Goldich’s weathering study
• Compare mollisols east and west of
pedalfer/pedocal boundary
• Prairie/forest boundary
• Literature/bibliographic and final lab
projects
Main topics - Geology of Soils
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Soil profile description
Factors of soil formation
Soils mapping and suitability
Weathering and pedogenesis
Soil conservation; agriculture
Organic soils
Soil classification
Soils for Quaternary geology and
archaeology
Local sources of information and
help
• Natural Resources
Conservation Service
(Tom Coffman)
• Rice County Soil and
Water Conservation
District (Theresa
Weninger)
Local sources of information and
help
• University of
Minnesota County
Extension - Brad
Carlson
• University of
Minnesota Soils,
Water and Climate,
Climate Gyles Randall,
SROC
- Gyles David
Mulla, Steve
Randall,
David
Simmons
Mulla,
Steve Simmons
(agronomy)
Studying a Soil Profile
Visiting farms
Animal agriculture and soils
Jirik farm (above)
Southern Research and
Outreach Station, UMN
(right)
Student final projects, 1999
• Do the soils in the prairie restoration areas
of the arboretum exhibit significant
differences in soil texture?
• Is the new proposed site for the Farm Club
garden appropriate for tilling, etc? How
does it compare to the old site?
• How has pine planting affected soil
development in the lower arb?
More student final projects
• What conservation practices are being used
to control water erosion on Rice County
farms and how effective are they?
• What are the possible land uses and land
use restrictions imposed by soil properties
near Blue, Texas?
• What are the soil differences between forest
and restored prairie near Nerstrand?
Conclusions
• A soils course at a place like Carleton can:
– help students develop a “sense of place” in rural
America
– give students a grounding in agricultural
resources, both of the US and elsewhere
– be an integral part of a geology major
– link environmental science and global
biogeochemistry courses
Soils R Fun
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Pete Birkeland - CATENA supermarket
Francis Hole’s Soil Songs
Ian Smalley - Loess Inn
William Bryant Logan - Dirt: The Ecstatic
Skin of the Earth