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.