Beneath the snow now blanketing Michigan’s corn fields lays a valuable but underused commodity: corn stover. The term “stover” refers to all of the leaf, stalk and cob tissue commonly left after grain harvest. Grain gets all of the attention, but only accounts for 50 percent of each corn crop by weight. This means that the average acre of corn in Michigan yields approximately four tons of stover material on an annual basis. Corn stover has traditionally been returned to the soil as an important source of organic matter and plant nutrients. Yet, increasingly tight margins in the crop and cattle sectors have some producers looking to capture additional value from this abundant co-product.
In some ways, harvest and feeding of corn stover seems perfectly simple. Volatility in hay and corn grain markets, made worse by the drought of 2012, has pushed livestock producers to seek out alternative forages. Due to its relative low cost and ubiquitous availability, corn stover is quickly gaining recognition as a viable option for a portion of the forage component in ruminant livestock rations. Corn stover’s greatest drawback is the fact that it contains only one-third the protein of average quality hay. Yet careful supplementation of stover with high protein feeds like forage brassicas or dry distiller grains can overcome this deficit.
However, it is important to remember that removing crop residue from the field has the potential to negatively impact long-term soil health. Stover protects the soil from the erosive forces of wind and water. It also returns carbon and nutrients to the soil as it is decomposed by soil biota. Fortunately, a tool known as the Lucas Soil Organic Matter Calculator now makes it possible to use baseline soil data and information regarding production practices like tillage, manure and cover crop use to predict how much corn stover could be removed without compromising soil health. Stover harvest activities should generally be concentrated on fields receiving abundant organic matter inputs in other forms.
Grazing is likely the simplest way to capture additional value from corn stover. An average acre of stover will feed a single cow for 30-45 days. Like any grazed forage, feed quality will decline every day animals are on stover and supplemental feeding will be necessary to maximize utilization. Yet extending the fall grazing season can be invaluable in years when forage yields are low and prices are high. Producers commonly face several obstacles to stover grazing including field location, fencing options and access to water. Despite these challenges, grazing is almost always more efficient than stover harvest, transport and manure hauling.