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Title: IMPACT OF MANURE AND N-MANAGEMENT SYSTEMS ON WATER QUALITY

Author
item KANWAR, RAMESHWAR - IOWA STATE UNIVERSITY
item Karlen, Douglas
item Cambardella, Cynthia
item Colvin, Thomas
item PEDERSON, CARL - IOWA STATE UNIVERSITY

Submitted to: Integrated Crop Management Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/20/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Alternative farming practices that reduce input costs, preserve the resource base for agricultural production, and protect the environment are needed for a sustainable future. This study was started in 1993 to evaluate effects of nine systems involving N fertilizer management strategies, use of swine manure, chisel-plow and no-tillage practices, and crop rotations on crop yield and N loss through tile drainage. It is being conducted near Nashua, Iowa, on a site that is predominately Kenyon silty-clay loam soil with 3 to 4% organic matter. Achieving the desired N application rate with swine manure continues to be a difficult problem and has resulted in insufficient or excessive amounts of N in the first four years of this study. These manure application problems have affected N leaching losses through the tile drainage system. Use of the late-spring soil nitrate test to adjust fertilizer N rates resulted in lower tile drainage loss of N than the single preplant fertilizer application even though the total amount of N applied was greater. Use of narrow strip cropping involving corn, soybean, and oat or growing alfalfa resulted in the lowest loss of N through the drainage water. These results demonstrate the effectiveness of using soil tests to determine appropriate fertilizer N rates and encourage the adoption of more diverse crop rotations as environmentally sustainable soil and crop management practices.