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Journal of Environmental Quality Abstract -

Optimizing Nitrogen and Irrigation Inputs for Corn Based on Nitrate Leaching and Yield on a Coarse-Textured Soil


This article in JEQ

  1. Vol. 25 No. 5, p. 982-992
    Received: Feb 23, 1995

    * Corresponding author(s): moncrief@soils.umn.edu
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  1. B. T. Sexton,
  2. J. F. Moncrief *,
  3. C. J. Rosen,
  4. S. C. Gupta and
  5. H. H. Cheng
  1. Department of Soil, Water, and Climate, 439 Borlaug Hall, 1991 Upper Buford Circle, Univ. of Minnesota, St. Paul, MN 55108.



A study was conducted on a Verndale sandy loam soil (coarse loamy over sandy, mixed, frigid Udic Argiboroll) during 1991 and 1992 at Staples, MN, to assess the influence of irrigation scheduling and N source and rate on corn (Zea mays L.) yield and nitrate leaching. Nitrogen sources were urea and turkey manure. Soils were irrigated to field capacity (i) at a fixed trigger deficit throughout the season, or (ii) at a variable trigger deficit based on crop growth stage. Leaching losses were calculated from measured daily fluxes of water percolation and soil water NO3-N concentrations and from a seasonal N mass balance. Based on yield response curves, maximum corn grain yields were obtained at 202 and 234 kg N ha−1 urea in 1991 and 1992, respectively. This resulted in growing season leaching losses of 72 and 55 kg N ha−1 in 1991 and 1992, respectively. The rate at 95% of the maximum crop yield is suggested to substantially reduce nitrate leaching past the root zone. Using this guideline, nitrate leaching would be reduced by 35% compared with nitrate leaching at the maximum yield. When a variable available water deficit was used to schedule irrigation compared with a fixed deficit schedule (at 95% of maximum yield N rate), nitrate leaching was reduced 46%. At equivalent N rates, turkey manure produced equal or greater crop yields as that from urea applications; however, nitrate leaching was equal to or less than urea.

Contribution from the Dep. of Soil, Water and Climate, Univ. of Minnesota, St. Paul, MN 55108 and the Minnesota Agric. Exp. Stn., Scientific Journal Series, Paper 21,715.

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