Readings

Keeney, D.R., and J.L. Hatfield. The nitrogen cycle, historical perspective, and current and potential future concerns. In: Follett, R.F., and Hatfield, J.L. Nitrogen in the Environment: Sources, Problems, and Management. 2001.
Foth, H.D., and Ellis, B.G. Soil Fertility, 2nd.ed. Chapter 6. Nitrogen (part). 1997.
Council for Agricultural Science and Technology, “Gulf of Mexico Hypoxia: Land and Sea Interactions,” Task Force Report, June 1999.

Key Questions

The Nitrogen Cycle, Historical Perspective, and Current and Potential Future Concerns

How does the amount of nitrogen brought into global circulation from anthropomorphic sources compare to that which is fixed naturally?
Which human activity brings the maximum amount of fixed nitrogen into circulation?
What are the local and global consequences of the increased N levels in our surroundings?
What is the MCL allowed for nitrate nitrogen in drinking water? What are the arguments against this levels?
What factors complicate regulation of N levels in ground water?
Which are the nutrients of concern when we consider the problem of eutrophication and hypoxia in freshwater, and, ocean and estuaries?
What factors affect movement of nitrogen into ground and surface waters?
What is the general use of nitrogen use and manure production in the US over the 15 years?
What different routes does the author suggest for improving nitrogen fertilizer use efficiency?

Soil Fertility

What are the major storehouses of nitrogen?
What are the dominant forms of nitrogen in soils?
What is the importance of biologically fixed nitrogen with reference to the overall amount of nitrogen that is added to soils?
What is the difference between symbiotic and non symbiotic nitrogen fixation? What are some of the examples for the two different mechanisms?

Gulf of Mexico Hypoxia

People who viewed this content, also viewed...