Bakko, Eugene. Personal Interview. 16 March 2005.

Bellis, Mary. “Agriculture and Farm Innovations.” http://inventors.about.com/library/inventors/blfarm.htm (accessed May 2005).

Bird, Elizabeth Ann R., Gordon L. Bultena, and John C. Gardner, ed. Planting the Future: Developing an Agriculture that Sustains Land and Community. Ames, IA: Iowa State University Press, 1995.

Copeland, P. J., and R. K. Crookston. “Crop Sequence Affects Nutrient Composition of Corn and Soybean Grown Under High Fertility.” Agronomy Journal 84.3 (1992): 503-9.

Crookston, R. K., and J. E. Kurle. “Corn Residue Effect on the Yield of Corn and Soybean Grown in Rotation.” Agronomy Journal 81.2 (1989): 229-32.

Jackson, Wes, Wendell Berry, and Bruce Colman, ed. Meeting the Expectations of the Land: Essays in Sustainable Agriculture and Stewardship. San Francisco: North Point Press, 1984.

Jordan, N., et al. “Simulation Analysis of Crop Rotation Effects on Weed Seedbanks.” American Journal of Botany 82.3 (1995): 390-8.

Kanwar, RS, et al. “Transport of Nitrate and Pesticides to Shallow Groundwater System as Affected by Tillage and Crop Rotation Practices.” Agricultural Research to Protect Water Quality: Proceedings of the Conference February 21-24, 1993 Minneapolis, Minnesota, USA, 1993. 270-273.

Logsdon, Gene. Living at Nature’s Pace: Farming and the American Dream. White River Junction, VT: Chelsea Green Publishing Company, 2000.

Melvin, SW, et al. “Nitrogen Management and Crop Rotation Effects on Nitrate Leaching, Crop Yields, and Nitrogen use Efficiency.” Agricultural Research to Protect Water Quality: Proceedings of the Conference February 21-24, 1993 Minneapolis, Minnesota, USA, 1993. 411-415.

Moomaw, R. S. “Selected Cover Crops Established in Early Soybean Growth Stage.” Journal of Soil and Water Conservation 50.1 (1995): 82-6.

Porter, Paul M., et al. “Crop Rotations: Organic and Other Management Strategies with Two- and Four-Year Crop Rotations in Minnesota.” Agronomy Journal 95.2 (2003): 233-244.

Rosenzweig, Cynthia, and Daniel Hillel. Climate Change and the Global Harvest: Potential Impacts of the Greenhouse Effect on Agriculture. New York, NY: Oxford University Press, 1998.

Schlebecker, John T. Whereby We Thrive: A History of American Farming 1607-1972. Ames, IA: The Iowa State University Press, 1975.

Schnepf, M. “National Policy Constraints and Solutions to Agricultural Contamination of Groundwater.” (1990).

Sharma, P., et al. “Impact of Alfalfa on Soil and Water Quality.” (1997).

Soule, Judith D., and Jon K. Piper. Farming in Nature’s Image: an Ecological Approach to Agriculture. Covelo, CA: Island Press, 1992.

Wilhelm, W. W., and C. S. Wortmann. “Tillage and Rotation Interactions for Corn and Soybean Grain Yield as Affected by Precipitation and Air Temperature.” Agronomy Journal 96.2 (2004): 425-32.