Transcript ESPM 120 Soil Characteristics

ESPM 120
“Soil Characteristics”
Fall 2007
Today
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Syllabus and expectations
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Soils and Berkeley and You
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Mini field trip (to Hilgard Hall)
Syllabus and expectations– main points
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Schedule subject to change
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Basic weekly structure
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Ask questions, be excited
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Respect each other
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Have fun
Soils and Berkeley and You
How are the following related to soil?
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Pizza
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Don Edwards Wildlife Refuge
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http://www.fws.gov/desfbay/habitats.htm
Your house/apartment
History of Pedology
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mid 19th Century: no scientific study of soils
Soil science followed closely behind development of
geology (early 19th century) and biology (Origin of
Species).
Two key contributors to development of Pedology
 Vasili Dokuchaev (Russian geographer/mineralogist)
 Eugene Hilgard (American geologist/chemist)
Eugene Hilgard and Soil Science at
Berkeley
Born
in Germany
Raised
family
in American frontier (Illinois) in intellectually oriented
Received
PhD at University of Heidelberg
Agricultural
Accepted
1855
chemistry and geology
position as Assistant State Geology of Mississippi in
Hilgard in Mississippi
Not
a glamorous job
Recognized
his future with state lie
not with geology but agriculture and
soils
Produced
a landmark document (next
slide) with half geology and half soils
The Mississippi Report
Detailed
discussion of
soil formation and soil
chemistry
“soil”
map of state….
Hilgard’s Agricultural Map
Analogous
to modern
generalized soil map
Map
units based on
geology and vegetation
Hilgard Moves to California
Recruited
1874
Replaced
by UC president in
first chair of
agriculture (who was fired)
Berkeley when Hilgard arrived….
Despite
cultural isolation
Hilgard seized opportunity
to expand College of
Agriculture (now CNR) and
make soils a national issue
Hilgard and John Wesley Powell (USGS)
Prodded
JW Powell to start a
national soil survey program (later
adopted by USDA)
Hilgard and his legacy….
Mountains, lakes, streets, buildings, journals are all named
after Hilgard
 His influence was international, inspiring the next generation
of scientists, particularly Hans Jenny……
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Hans Jenny and Soil Formation
Soils form predictably in
response to environmental
factors (Dokuchaev ~
1880)
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Hans Jenny (1920’s to
1930’s) transformed
conceptual model to a more
quantitative theory
following tenets of physical
chemistry
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State Factor Equation
Soil = f (initial conditions, external conditions, time)
or, based on field observation
Soils = f (climate, biota, topography, parent material, time, …. )
Key Concepts of State Factor Theory
Factors
System
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are independent of system
is small relative to surroundings
A change in variables defines a new system
there
are essentially an infinite number of soils
Mini Field Trip
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Soil Profiles
http://soils.usda.gov/technical/classification/osd/index.html
San Joaquin Series
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Extent map
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Typical pedon
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Natural vegetation
Next Time
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Chapter 1
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Handout
Study questions