Submitted to: Proceedings of the Symposium on Watershed Management
Publication Type: Proceedings
Publication Acceptance Date: March 30, 2000
Publication Date: N/A
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.