Notes on soils
Chapter 18 in the textbook is concerned with the geography of soils. Many students have difficulty imagining why anyone would find soil interesting. Consider, however, that the soil is the earth's skin, almost a living organism, and that it mediates many of the environmental processes that are essential to the survival of life on earth and that affect other important earth systems. It plays a role in the hydrologic cycle; in the weathering of rock to produce sediment and dissolved ions; in biogeochemical cycling of nutrients and other elements; in the accumulation and breakdown of organic matter, which in turn may affect the composition of the atmosphere; in the production of microbial and plant life, on which so much of the rest of the biosphere depends. There is so much to the story that we can't possibly do more than scratch the surface, and we won't even try to do so in our coverage of this topic.
Read chapter 18 through page 537 first. Most of the remainder of the chapter focuses on a review of the 11 major soil orders. This is an important classification scheme, but there is no way we can keep it all straight unless we spend more time on it, so I request that you scan it in enough depth that you come away with a basic idea about what the classification scheme itself is based on.
Next, visit the on-line set of course notes from the introductory soils course by Terry Cooper at the University of Minnesota. The Table of Contents for Soils Laboratory Units contains some excellent material that is easy to read and will give you a good sense of what soils are all about, how they form, and how soil characteristics are mapped for purposes of land management and planning. Units 1 through 4 from this site are required in conjunction with your reading of chapter 18 in our textbook.
Another good online source is the Soils Learning Module by Michel Ritter at University of Wisconsin-Stevens Point. This is part of his introductory Physical Geography course.
After you have reviewed these materials, go back and read the remainder of chapter 18.
In addition to reading these materials, I will assign each student in the class to study two of the twelve soil orders and prepare a set of answers to the following questions:
In choosing your two soil orders, note that Gelisols and Entisols show relatively little evidence of soil development and if any orders are left out, they should be these two.
Source materials used can include the textbook, WWW sites (such as The Twelve Soil Orders from University of Idaho, or Keys to Soil Taxonomy from the Natural Resources Conservation Service), or other materials such as library sources. The website of the National Soil Survey Center will provide access to lots of information sources once you have identified your soil order or a particular soil type or soil series within that soil order. Some international examples may be found at this site which leads to multiple sources of world soils data (a subset of the first site on the list below).
Your summary doesn't need to be any longer than about a page of text for each of your soil orders. Try to avoid getting overly tangled in the jargon - you'll find a lot of it in the soil taxonomy source listed above, which is why I've tried to keep the list of questions fairly practical.
Please post your answers on the bulletin board.
Here are some additional web sites with information on soils. When we address biomes next week, the connection between soils and biomes may be relevant enough for you to refer back to some of these.
The
World-Wide Web Virtual Library: Forestry: Soils and Substrates
Designations
of horizons and layers
USDA
Soil characterization laboratory
International Soil Reference and Information
Center
Soils
Information for Environmental Modeling
SCIENCES
of SOILS - Home Page
Zobler
World Soils Data Set
Dept.
of Soil Science, UW-Madison
National
Soil Data Access Facility Project Home Page
Soil
Survey Manual
Biodiversity,
soil and ecologically sustainable development
WHY
STUDY SOIL MOISTURE - from Alan Robock, Univ. Md. College Park, Meteorology
Dept.
Soil
Landscapes of Canada
Soil
Geography of US and Canada- Jeffrey S. Kern
Constraints
on Agricultural Suitability
Jeffrey
Kern - miscellaneous other sites related to soils, landscape, agricultural
sustainability, etc.