Does Bt Corn Require Different Tillage and Residue Management?


  • Determine if Bt and non-Bt hybrids differ with respect to the need for postharvest residue management and if selected postharvest residue management practices affect emergence, early growth, stand and yield in continuous corn production.

Study Description

Location: Arlington, WI
Plot Layout:      Randomized complete block, split-split-split plot design
Replicates: 4
  • Whole plot factor - Tillage (no-till vs. fall chisel)
  • 1st split plot factor - Corn hybrid (Bt vs. non-Bt)
  • 2nd split plot factor - Residue management (chopped vs. unchopped)
  • 3rd split plot factor - Fall nitrogen (N) fertilization (30 lbs N / acre as urea vs. none)
  • bt_corn_tillage_residue_mgmt1
    No-till corn (left) and chisel plot corn (right). Photo taken on June 29, 2012.

    • The site has been in continuous corn and tillage treatments have been in place since 2009.
    • The research site experienced severe drought stress in 2012. Results from the 2012 growing season can be interpreted as representative of treatment effects during drought conditions.


    • Corn yields were significantly (P ≤ 0.05) greater with fall chisel plowing than with no-till.
    • There was no significant yield difference (P ≤ 0.24) between non-Bt corn and Bt corn.
    • There was no significant yield difference (P ≤ 0.94) between unchopped and chopped residue.
    • There was no significant yield difference (P≤0.22) between fall N fertilization and no fall N fertilization.
    • Interaction effects were not significant.
    • These results are similar to results from previous and concurrent studies that indicate there is a yield drag with no-till continuous corn (relative to tilled continuous corn) and that fall N has no effect on improving yields through stimulation of residue decomposition.
    • Results do not indicate a need to manage crop residue differently in Bt corn vs. non-Bt corn

    Chart: Corn Yields Under Chisel Plow or No-Till Management

    *Different letters indicate a significant difference at the α=0.5 level.
    Error bars are standard error (SE).

    Research conducted by Matt Ruark, University of Wisconsin-Madison as a part of the Pioneer Crop Management Research Awards (CMRA) Program. This program provides funds for agronomic and precision farming studies by university and USDA cooperators throughout North America. The awards extend for up to 4 years and address crop management information needs of Pioneer agronomists, Pioneer sales professionals and customers.

    2012 data are based on average of all comparisons made in 1 location through November 2, 2012. Multiyear and multilocation is a better predictor of future performance. Do not use these or any other data from a limited number of trials as a significant factor in product selection. Product responses are variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary.