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This article in AJ

  1. Vol. 93 No. 4, p. 836-841
    Received: Sept 15, 2000

    * Corresponding author(s): adhalvor@lamar.colostate.edu
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Tillage and Nitrogen Fertilization Influence Grain and Soil Nitrogen in an Annual Cropping System

  1. Ardell D. Halvorson *a,
  2. Brian J. Wienholdb and
  3. Alfred L. Blackc
  1. a USDA-ARS, P.O. Box E, Fort Collins, CO 80522
    b USDA-ARS, 119 Keim Hall, East Campus, Univ. of Nebraska, Lincoln, NE 68583
    c USDA-ARS, 226 E. Circle Dr., Canon City, CO 81212


Increasing the frequency of cropping in dryland systems in the northern Great Plains requires the application of N fertilizer to maintain optimum crop yields. A 12-yr annual cropping rotation [spring wheat (Triticum aestivum L.)–winter wheat–sunflower (Helianthus annuus L.)] under dryland conditions was monitored to determine the influence of tillage system [conventional till (CT), minimum till (MT), and no till (NT)] and N fertilizer rate (34, 67, and 101 kg N ha−1) on N removed in grain and annual changes in postharvest soil NO3–N. Nitrogen removal in the grain increased with increasing N rate in most years. Total grain N removal was lowest with NT at the lowest N rate and highest with NT at the highest N rate compared with CT. Total grain N removal after 12 cropping seasons was 144, 84, and 61% of the total N applied for the 34, 67, and 101 kg N ha−1 fertilizer rates, respectively. Residual soil NO3–N levels were not affected by N rate or tillage system in the first 3 yr, but they increased significantly following consecutive drought years. Residual NO3–N in the 150-cm soil profile tended to be higher with CT and MT than with NT. Soil NO3–N movement below the crop root zone may have occurred in 1 or 2 yr when precipitation was above average. Results indicate that NT, with annual cropping, may reduce the quantity of residual soil NO3–N available for leaching compared with MT and CT systems.

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Copyright © 2001. American Society of AgronomyPublished in Agron. J.93:836–841.