Effect of Tillage and Cover Crops on Corn Yield

• Different tillage practices are utilized by farmers for various reasons including to:

  • Enhance residue decomposition
    
  • Control pests
    
  • Conserve soil moisture
    
  • Deliver fertilizer to the root zone
    
  • Relieve compaction
    

• Farmers also utilize cover crops in their crop production system. Potential benefits of cover crops are:

  • Soil conservation (erosion control) 
    
  • Soil moisture conservation
    
  • Weed suppression
    
  • Improved organic matter
    
  • Improved soil structure
    
  • Improved nutrient cycling

• In 2019, the Monmouth Learning Center established a trial to evaluate the interaction of certain tillage practices with the presence of a cover crop and the effect on corn yield. This is intended to be a long-term trial to monitor both yield and soil quality over time.

   

• Five zones were established in the fall of 2018 (Figure 1):
  • Conventional tillage without a cover crop
    
  • No-till without a cover crop
    
  • No-till with a cover crop 
    
  • Strip tillage without a cover crop
    
  • Strip tillage with a cover crop
    

• Cereal rye was sown in the relevant zones and respective tillage operations were performed in the fall of 2018.

• Following cover crop termination, a 114-day RM SmartStax® RIB Complete® corn blend product was planted in all plots. 

• Grain was harvested and adjusted to 15% moisture.

• In this trial, no-till plots had the lowest corn yield (Figure 2). Prolonged cold temperatures prior to planting likely hindered residue decomposition and seedling emergence, potentially affecting yields in those plots.¹ Rising temperatures after planting likely promoted rapid residue decomposition, which could reduce the amount of nitrogen available during the early season as microbes utilize soil nitrogen when decomposing crop residue.²

• Yields were similar between the strip-tilled plots and the conventionally-tilled plot.

   

• This was the first year of this trial; establishing tillage zones and improving soil structure and quality takes time.

• Cover crops may have other benefits beyond yield: moisture conservation, weed suppression, and nutrient cycling. These benefits are less tangible but may have an effect on profit potential.

• The Monmouth Learning Center has committed to conducting this study on a long-term basis to monitor the effects on yield and soil quality over time.

¹Archontoulis, S. and Castellano, M. 2018. Soil water, residue, and nitrogen status entering the 2018 growing season. Iowa State University. https://crops.extension.iastate.edu/.

²University of Nebraska – Lincoln. 2017. Crop residue removal: impacts on yield. No-Till Farmer. https://www.no-tillfarmer.com.

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Cover Cropping and Tillage Systems in Soybean Production