Influence of no-till and a winter rye cover crop on nitrate losses from tile-drained row-crop agriculture in Iowa.

Artificial subsurface drainage is necessary to maintain agricultural production in the soils and climate of north-central Iowa. However, it can result in adverse environmental impacts, because it intercepts and diverts some water and soluble NO -N directly to streams. We investigated the impact of no-till and a winter rye cover crop (Secale cereale L.