Hydric Soils Exercise

Wetland Environments
James S. Aber


Begin by opening the homepage for hydric soils at the USDA Natural Resources Conservation Service. Read the Introduction for an overview of hydric soils, and answer the following questions. Answers should be given in your own words--no copy and paste.

1. What is a hydric soil?

2. What are field indicators and what purpose do they serve?

Now find the section for state lists of hydric soils. Click on Kansas and scroll down to the Osage Soil series. The Osage is found on floodplains of river valleys in the eastern portion of Kansas.

3. For the Osage Soil, identify the hydric criteria numbers and explain what they mean--see hydric criteria.

Most soils in Kansas are Mollisols. The hydric suborder is called Aquoll, which includes the Osage Soil. Now visit the soil orders homepage at the University of Idaho. Click on the Mollisol category.

4. What are the main characteristics of Mollisols?

5. In which U.S. states and geographic regions are Mollisols particularly abundant? Where else in the world are Mollisols common?

6. From the list of examples, select one wetland Mollisol, as identified by the "aqu" term in the name. Identify the soil and briefly describe why it is a wetland soil.

Return now to the soil orders homepage, and check out Histosols.

7. What are the main characteristics of Histosols?

8. In which U.S. states and geographic regions are Histosols particularly abundant? Where else in the world are Histosols common?

9. From the list of examples, select one Histosol. Identify the soil and briefly describe why it is a wetland soil.

You have gained some familiarity with hydric soils in the United States. Revisit the homepage for hydric soils at the USDA Natural Resources Conservation Service. Scroll down and click on Field Indicators of Hydric Soils (large pdf file). Advance to page 7 in this pdf file, and begin reading. Answer the following questions; answers should be given in your own words--no copy and paste.

10. What does the term anaerobiosis refer to and how does it come about?

11. Biogeochemical processes in wet soils lead to accumulation (or loss) of chemical compounds involving what four key elements?

12. What is the significance of a "rotten egg" (hydrogen sulfide) smell? Do all hydric soils display this indicator?

13. What are the basic characteristics of a Histosol?

14. Locate Figure 37 (page 34 of pdf file). For a soil with 60% clay content, how much organic carbon is required for a) organic soil and b) mucky mineral soil?

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© Notice: Wetland Environments is presented for the use and benefit of students enrolled at Emporia State University. Any other use of text, imagery or curriculum materials is prohibited without permission of the course webmaster, J.S. Aber (2007).