EARTHWORM DELIGHT. An earthworm drags corn stalk residue into its hole, leaving behind some larger pieces. Earthworms like the fibers in the pith of the stalk, and chopping residue exposes the fibers.

Feed Earthworms, Improve Yields By Chopping Residue

Veteran no-tiller Marion Calmer uses earthworms to manage residue in his Alpha, Ill., no-till system.

Marion Calmer sees residue as either an asset or a liability — depending on how you manage it. 

Calmer, the longtime no-tiller and ag entrepreneur from Alpha, Ill., has been conducting on-farm research since 1985 when he first started no-tilling. In recent years, he started studying his soil inch by inch to better understand the relationship between earthworms and residue management. 

His fields in western Illinois are silty loam soils that are dark in color with high organic matter and a good supply of phosphorus (P), nitrogen (N) and potassium (K). In 2021, he averaged 65 pounds per acre of P and 279 pounds of K. The best fields in the area have about 16 inches of topsoil. 

In his attempt to understand how earthworms impact residue management in his fields, Calmer set up experiments to assess the size of the residue, its horizontal distribution, vertical stratification of organic matter and pH, and impact on yield. 


  • Chopping corn stalks opens up the pith, allowing earthworms to grab the fibers and take pieces below the surface.
  • Results from Marion Calmer’s on-farm trials show vertical stratification of organic matter and pH doesn’t exist. His soil tests, which analyzed soil at every inch up to 8 inches deep, indicated organic matter and pH were evenly distributed.
  • Smaller residue that’s the right size for earthworms promotes faster decomposition, which resulted in a 6 bushel per acre yield increase in continuous corn and a 4 bushel per acre increase for soybeans.
  • On-farm research…
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Michaela paukner

Michaela Paukner

Michaela Paukner is the managing editor of No-Till Farmer, Strip-Till Farmer and Cover Crop Strategies. Her previous journalism experience includes working as a reporter for a legal magazine and as a producer for two Wisconsin TV news stations. She has also worked with clients across the globe as a freelance writer and marketing consultant, and as a brand manager for a Wisconsin-based boutique marketing agency. She's a graduate of the University of Wisconsin-Green Bay.

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