- Количество слайдов: 31
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 1990 s
• Carleton History of Agriculture 2 Renewed student interest in environment, agriculture starting in 1970 s • 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 1870 s • Department founded in 1933 by Laurence Mc. Kinley 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 • • 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 • Q 1: What are the observable characteristics of soils? • Q 2: How do soils get to be this way? • Q 3: 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, SROC - Gyles Randall, David Mulla, Steve Simmons (agronomy)
Studying a Soil Profile
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