Controlling Nitrate Leaching in Irrigated Agriculture

ABSTRACT The impact of improved irrigation and nutrient practices on ground water quality was assessed at the Nebraska Management System Evaluation Area using ground water quality data collected from 16 depths at 31 strategically located multilevel samplers three times annually from 1991 to 1996. The site was sectioned into four 13.4‐ha management fields: (i) a conventional furrow‐irrigated corn (Zea mays L.) field; (ii) a surge‐irrigated corn field, which received 60% less water and 31% less N fertilizer than the conventional field; (iii) a center pivot‐irrigated corn field, which received 66% less water and 37% less N fertilizer than the conventional field; and (iv) a center pivot‐irrigated alfalfa (Medicago sativa L.) field. Dating (3H/3He) indicated that the uppermost ground water was