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Improving Nitrogen Use Efficiency for Cereal Production

Raun, William R., Johnson, Gordon V.
Agronomy journal 1999 v.91 no.3 pp. 357-363
Triticum aestivum, Zea mays, Oryza sativa, Oryza glaberrima, Hordeum vulgare, Sorghum bicolor, Pennisetum glaucum, Avena sativa, Secale cereale, nitrogen, nutrient uptake, nitrogen fertilizers, losses from soil, denitrification, runoff, volatilization, leaching, harvest index, crop management, ammonium nitrogen, precision agriculture, nitrogen fixation, crop yield, nitrogen metabolism, emissions, application rate
Worldwide, nitrogen use efficiency (NUE) for cereal production (wheat, L.; corn, L.; rice, L. and Steud.; barley, L.; sorghum, (L.) Moench; millet, (L.) R. Br.; oat, L.; and rye, L.) is approximately 33%. The unaccounted 67% represents a $15.9 billion annual loss of N fertilizer (assuming fertilizer-soil equilibrium). Loss of fertilizer N results from gaseous plant emission, soil denitrification, surface runoff, volatilization, and leaching. Increased cereal NUE is unlikely, unless a systems approach is implemented that uses varieties with high harvest index, incorporated NH-N fertilizer, application of prescribed rates consistent with in-field variability using sensor-based systems within production fields, low N rates applied at flowering, and forage production systems. Furthermore, increased cereal NUE must accompany increased yields needed to feed a growing world population that has yet to benefit from the promise of N-fixing cereal crops. The Consultative Group on International Agricultural Research (CGIAR) linked with advanced research programs at universities and research institutes is uniquely positioned to refine fertilizer N use in the world via the extension of improved NUE hybrids and cultivars and management practices in both the developed and developing world.