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Title: INTENSIVE N 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: Proceedings of the Symposium on Watershed Management
Publication Type: Proceedings
Publication Acceptance Date: 3/30/2000
Publication Date: N/A
Citation: N/A

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 in nitrate content of 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 by soil sampling results. While designed to provide optimum N fertilizer rate and timing, the impact of adopting the LSNT on water quality had not previously been quantified at the watershed scale. Preliminary statistical analyses indicate a significant reduction in nitrate concentration of tile drainage (average of 4.3 ppm nitrate-N) from the treatment area compared to the control area.