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

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 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)

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

• Pete Birkeland - CATENA supermarket

• Francis Hole’s Soil Songs

• Ian Smalley - Loess Inn

• William Bryant Logan - Dirt: The Ecstatic Skin of the Earth