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Title: INTENSIVE NITROGEN FERTILIZER MANAGEMENT EFFECTS ON WATER QUALITY AT THE WATERSHED SCALE

Author
item Dinnes, Dana
item Jaynes, Dan
item Meek, David
item Cambardella, Cynthia
item Colvin, Thomas
item Hatfield, Jerry
item Karlen, Douglas

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/8/2000
Publication Date: 3/8/2000
Citation: Dinnes, D.L., Jaynes, D.B., Meek, D.W., Cambardella, C.A., Colvin, T.S., Hatfield, J.L., Karlen, D.L. 2000. Intensive nitrogen fertilizer management effects on water quality at the watershed scale. Proceedings of Agriculture and the Environment: A Wake-Up Call for Iowans. Iowa State University Extension, Ames, Iowa.

Interpretive Summary:

Technical Abstract: Our project, the Walnut Creek Nitrogen Initiative, addresses a prevalent environmental issue of the Midwest, nitrate contamination of agricultural field tile drainage waters. The project's objective is to quantify changes of nitrate content in tile flow as a result of implementing intensive N fertilizer management at the watershed scale. We are using the Late-Spring Soil Nitrate Test (LSNT) method of managing N fertilizer for corn production. With this system, N fertilizer is applied in split applications: the first application is a nominal rate shortly before or at planting and the second soon after late-spring soil sampling with the rate determined from soil analyses. The LSNT method is designed to provide optimum N fertilizer rate and timing. This is the first research project to attempt to quantify the impact of adopting the LSNT method on water quality at an environmentally meaningful scale. Preliminary statistical analyses indicate a significant reduction in the nitrate concentration of tile drainage (average of 4.3 ppm nitrate-N) from the treatment area compared to the control area.