Nutrient Content of Tile Drainage From Cropland in the North Central Region
1980
Logan, Terry J. | Randall, Gyles Wade | Timmons, Donald Ralph
Tile drainage is a major practice on the millions of hectares of poorly drained cropland in the North Central Region, and nutrients in tile flow are a significant contribution to the total nutrient export from this area. Several studies at North Central Region institutions have monitored nutrients in tile drainage under varying soil, crop, and climatic conditions. This publication summarizes precipitation, tile flow, and nitrogen and phosphorus losses from tile drainage experiments in Iowa, Minnesota, and Ohio, and is intended fro researchers and water quality management planners. Tile flows varied from 0 to 40 cm per year and reflected annual variations in precipitation for the most part, but also differences in soil physical properties and ET. Nitrate-N losses were generally < 30 kg N/ha but increased with nitrogen fertilizer applications in excess of crop needs. Nitrate losses with alfalfa were very low. Phosphorus losses were in anon-reactive form. Except where nitrogen in excess of crop requirements is applied, the quality of tile drainage water is usually better than runoff water, especially with respect to phosphorus.
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