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This article in AJ

  1. Vol. 91 No. 4, p. 702-707
    Received: June 30, 1998

    * Corresponding author(s): adhalvor@lamar.colostate.edu


Dryland Winter Wheat Response to Tillage and Nitrogen within an Annual Cropping System

  1. Ardell D. Halvorson *a,
  2. Alfred L. Blackb,
  3. Joseph M. Krupinskyb and
  4. Stephen D. Merrillb
  1. a USDA-ARS, Soil-Plant-Nutrient Res., P.O. Box E, Fort Collins, CO 80522 USA
    b USDA-ARS, Northern Great Plains Res. Lab., P.O. Box 459, Mandan, ND 58554 USA


Winter wheat (Triticum aestivum L.) can add diversity to dryland crop rotations in the northern Great Plains, but it is susceptible to winterkill in low surface residue environments. A 12-year study was conducted to determine the response of two winter wheat cultivars, Roughrider and Norstar, to tillage system (conventional-till, CT; minimum-till, MT: and no-till, NT) and N fertilizer rate (34, 67, and 101 kg N ha−1) in a dryland spring wheat–winter wheat–sunflower (Helianthus annuus L.) rotation. Grain yields were greater with MT (1968 kg ha−1) and NT (2022 kg ha−1) than with CT (1801 kg ha−1), but tillage system effects on grain yield varied among years. Increasing N rate from 34 kg N ha−1 to 67 kg N ha−1 increased grain production from 1844 to 1953 kg ha−1, but yield response to N rate varied among years. The greatest overall grain yield (2111 kg ha−1) was obtained with NT and application of 101 kg N ha−1 Grain yields were lowest during years when plant-available water (PAW) was <300 mm. In years with >400 mm PAW, leaf spot disease incidence was greatest, particularly at the lowest N rate with NT. Application of adequate N reduced the disease incidence in all tillage treatments. Cultivar differences were significant 3 out of 12 years, but not consistent. Winterkill was a factor for both cultivars in only 1 year in the CT and MT plots. Winter wheat performed well as a rotational crop in this cropping system when using MT and NT systems and adequate N fertility. Our long-term results indicate that producers in the northern Great Plains can use winter wheat successfully in annual cropping systems that do not include a fallow period, particularly if NT is used with adequate N fertilization.

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