As the season winds down, farmers have to decide whether or not to harvest their stover. To help assist farmers, the Michigan Corn Stover Project has developed three articles to inform their decision-making process. This article covers the effects of integrating cover crops into corn production.

Key findings

  • Adding harvested winter cereal cover crops increases biomass and ethanol yields per acre.
  • Whether harvested or not, winter cereal cover crops provide several ecosystem services such as additional ground cover, nutrient recycling and reducing soil erosion.
  • A two-harvest system (fall and spring) produced the highest yield. An analysis of the two-harvest system needs to be made on a farm-by-farm basis to determine if the second harvest is economically feasible.

The Michigan Corn Stover Project was a collaborative effort at Michigan State University Extension to investigate the uses of corn stover and potential impacts of harvest in Michigan. This effort was comprised of on-farm and small scale research conducted across Lower Michigan. It included a cattle feeding study, integrating a cover crop, bale storage study, harvest time evaluation and the impact of stover removal on yield of the subsequent crop. Funding for the multi-year project was obtained from the Michigan Corn Marketing Board and MSU’s Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs).

The cover crop integration study evaluated the yield and quality of mixed biomass feedstocks resulting from the addition of an inter-seeded winter annual cereal cover crop, cereal rye or triticale, with corn stover. Agronomic decisions about planting densities, hybrid selection, nutrient management and herbicide application followed local best management practices as recommended by MSU Extension. Cropping systems evaluated included:

  • Corn stover only, harvested in fall.
  • Corn stover only, harvested in spring.
  • Corn stover with a winter cereal cover crop harvested in fall and spring.
    • The fall harvest feedstock was primarily corn stover due to the limited time frame for growth of the fall-planted winter cereals.
    • The spring harvest consisted primarily of winter annual cereal crop biomass since the stover fraction had been effectively removed during the fall harvest.
  • Corn stover with a winter cereal cover crop only harvested in the spring

The two-harvest system had greater dry matter, ethanol, crude protein and energy content compared with the spring one-harvest system. However, there may be no economic advantage when the cost of the second harvest pass is factored in. If assuming the cost of the second pass outweighed the nutritive advantage, a single corn stover fall harvest would have the greatest yield for ethanol production.

If harvesting stover for cattle feed, a single pass harvest in fall is recommended to avoid yield loss due to over-wintering in the field. If harvesting in the spring is planned, a winter annual cover crop should be interseeded in the fall to offset the stover’s overwinter decrease in yield, crude protein and digestibility. Although triticale’s nutritive concentration was higher, its yield was lower, making the two cover crops we tested equally beneficial for cattle feeding.

For more information on corn stover, please visit our other articles:

The Michigan Corn Stover Project – Part 1: Bale storage study

The Michigan Corn Stover Project – Part 3: Cattle feeding study

Michigan Corn Stover Project: Cattle, Storage and Bioenergy