Nitrogen, found in commercial fertilizers and manure, is applied in many different chemical forms. Bacteria can convert all of them to nitrate, a form of nitrogen that can be taken up by plant roots. Nitrate is very soluble in water and is easily carried from farm fields into streams and rivers. Perforated pipes called tiles, which farmers bury under their fields to manage water drainage in an effort to maximize crop production, make the situation worse. Nitrate quickly moves through the soil and enters the tiles, which then rapidly pour drainage water and nitrate to streams and rivers. Nitrate-laden runoff.
