Soils in the Carleton undergraduate liberal-arts
curriculumMary 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
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
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 1979-2001
• 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
• 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
• Text - Birkeland: Soils and Geomorphology
• Emphasis - Weathering, pedogenesis, soils as chronological markers, soil mechanics
• Texts - Singer and Munns: Soils + Birkeland, et al., Soils. . .Applied Quaternary Geology (Utah GMS) + William Logan Bryant, Dirt: The Ecstatic Skin of the 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• 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 - Gyles Randall, David Mulla, Steve Simmons
• University of Minnesota County Extension - Brad Carlson
• University of Minnesota Soils, Water and Climate, SROC - Gyles Randall, David Mulla, Steve Simmons (agronomy)
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