Field-scale nitrogen balances associated with long-term continuous corn production

• Published in: Agronomy journal 1998-09, Vol.90 (5), p.644-650
• Main Authors: Karlen, D.L. (USDA, ARS, Natl. Soil Tilth Lab., Ames, IA.), Kramer, L.A, Logsdon, S.D
• Format: Article
• Language: English
• Subjects: ABSORCION DE SUSTANCIAS NUTRITIVAS; ABSORPTION DE SUBSTANCES NUTRITIVES; Agronomy. Soil science and plant productions; APPLICATION DATE; APPLICATION RATES; AZOTE; BALANCE HIDRICO DEL SUELO; BASSIN VERSANT; BILAN HYDRIQUE DU SOL; Biological and medical sciences; CARACTERISTICAS MORFOLOGICAS SUELO; CHIMIE DU SOL; CONTINUOUS CROPPING; CROP YIELD; CUENCAS HIDROGRAFICAS; CULTIVO CONTINUO; CULTURE CONTINUE; DATE D'APPLICATION; DENITRIFICACION; DENITRIFICATION; DEPTH; DOSE D'APPLICATION; DOSIS DE APLICACION; FECHA DE APLICACION; FERTILIDAD DEL SUELO; FERTILITE DU SOL; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; GROUNDWATER POLLUTION; IOWA; LABRANZA; LEACHING; LESSIVAGE DU SOL; LIXIVIACION; LOESS; LOESS SOILS; METABOLISME DE L'AZOTE; METABOLISMO DEL NITROGENO; NITRATE; NITRATES; NITRATOS; NITROGEN; Nitrogen fertilization; NITROGEN METABOLISM; Nitrogen, phosphorus, potassium fertilizations; NITROGENO; NUTRIENT UPTAKE; POLLUTION DE L'EAU SOUTERRAINE; POLUCION DE AGUAS SUBTERRANEAS; PRECIPITACION ATMOSFERICA; PRECIPITATION; PROFONDEUR; PROFUNDIDAD; QUIMICA DEL SUELO; RENDEMENT DES CULTURES; RENDIMIENTO DE CULTIVOS; Soil and water pollution; SOIL CHEMISTRY; SOIL FERTILITY; SOIL MORPHOLOGICAL FEATURES; Soil science; SOIL WATER BALANCE; Soil-plant relationships. Soil fertility. Fertilization. Amendments; SOL DE LOESS; TILLAGE; TRAIT MORPHOLOGIQUE DU SOL; TRAVAIL DU SOL; VOLATILISATION; VOLATILIZACION; VOLATILIZATION; WATERSHEDS; ZEA MAYS
• ISSN: 0002-1962; 1435-0645
• DOI: 10.2134/agronj1998.00021962009000050013x

Excessive residual soil NO3-N indicates economic inefficiency for producers and increases the potential for nonpoint leaching of N to water resources. Our objective was to construct an approximate field-scale N budget for continuous corn (Zea mays L.) grown on deep loess soils in four 30- to 60-ha field-scale watersheds in western Iowa. Preplant and postemergence soil NO3-N levels were determined for the 0- to 30-cm, 30- to 60-cm and 60- to 90-cm depths in April before N fertilizer was applied and again at the V6 growth stage. A simple root-zone water balance and N removal by corn grain were determined. The 4-yr average showed approximately 100 kg ha(-1) of NO3-N in the upper 90 cm of the root zone before an average of 168 kg of fertilizer N ha(-1) was applied. Grain removal accounted for 30 to 70% of the fertilizer N. There were significant differences in grain yield and N removal among the four watersheds. Factors contributing to those differences included different fertilizer rates, tillage and application times. During the four study years, an average of 50% of the applied N was available for leaching, denitrification, and/or NH3 volatilization. High levels of residual soil NO3-N following continuous corn production coupled with steady percolation of precipitation that infiltrated but was not used by the corn crop appear to be the two major factors supplying NO3-N to groundwater baseflow that enters streams during the watersheds. Based on the seasonal water balance, the most successful N management strategies will be those that minimize the amount of residual NO3-N remaining in the soil profile at the end of the growing season