Nitrogen management in dryland cropping systems

• Published in: Journal of production agriculture Vol. 9; no. 2
• Main Authors: Westfall, D.G. (Colorado State University, Fort Collins, CO.), Havlin, J.L, Hergert, G.W, Raun, W.R
• Format: Journal Article
• Language: English
• Published: 01.04.1996
• Subjects: ABONADO LOCALIZADO; ABONOS; ABONOS NITROGENADOS; AGRICULTURE INTENSIVE; AGUA SUPERFICIAL; ANALISIS DEL SUELO; ANALYSE DE SOL; ARIDOCULTURE; AZOTE; CALIDAD DEL AGUA; CERO-LABRANZA; CICLO DEL NITROGENO; CONDUITE DE LA CULTURE; CULTIVO EN TIERRAS ARIDAS; CYCLE DE L'AZOTE; DOSE D'APPLICATION; DOSIS DE APLICACION; DURABILITE; EAU SUPERFICIELLE; ECHANTILLONNAGE; ENGRAIS; ENGRAIS AZOTE; EPANDAGE LOCALISE; ETATS UNIS; EUA; EXIGENCE DES PLANTES; EXPLOTACION AGRICOLA INTENSIVA; HELIANTHUS; IMPACT SUR L'ENVIRONNEMENT; IMPACTO AMBIENTAL; LABRANZA MINIMA; LESSIVAGE DU SOL; LIXIVIACION; MANEJO DEL CULTIVO; MINERALISATION; MINERALIZACION; MUESTREO; NECESIDADES DE LAS PLANTAS; NITRATE; NITRATOS; NITROGENO; NON TRAVAIL DU SOL; NUTRIENTES; QUALITE DE L'EAU; RENDEMENT DES CULTURES; RENDIMIENTO DE CULTIVOS; SISTEMAS DE CULTIVO; SOSTENIBILIDAD; SUBSTANCE NUTRITIVE; SYSTEME DE CULTURE; TRAVAIL DU SOL MINIMAL; TRITICUM; ZEA MAYS
• ISSN: 0890-8524; 2689-4114
• DOI: 10.2134/jpa1996.0192

Management of fertilizer N in dryland cropping systems in the semi-arid Great Plains is important to the economic and environmental sustainability of these systems. As producers shift from the traditional tilled winter wheat (Triticum aestivum L.)-fallow (WF) cropping systems to those that include summer crops in the rotation, N management becomes more important because yield losses as a result of underfertilization become greater. Fertilizer N rate is more important in obtaining optimum yields of dryland crops than N placement in drier environments, while placement becomes more important as rainfall increases. Soil testing is an accurate method of quantifying the residual soil nitrate-N level in the root zone. However, a combination of soil testing, fertilizer N experiences of the producer, and projected N requirement (expected yield) are the best factors producers can use in determining fertilizer N rates. If soil testing occurs early in the spring/summer fallow period preceding planting, a correction to the fertilizer N recommendation should be made to account for N mineralization that occurs between soil sampling and planting. This can prevent overfertilization. Dryland systems appear to have a soil-plant N buffer capacity that prevents inorganic N accumulation at fertilizer N rates that exceed optimal N requirements to meet crop needs. Recent research has reported N buffering in the range of 21 to 76 lb N/acre per yr for annually cropped dryland wheat production systems. This means that the application of from 21 to 76 lb N/acre per yr did not result in an accumulation of inorganic N in the soil. This concept should be evaluated on additional datasets, and, if found to be applicable to a range of conditions, it could have an effect on establishing environmentally safe fertilizer N rates for dryland cropping systems