By Elizabeth Niven
With increased corn yields, Midwest farms are producing more grain and stover in their fields. Corn stover, the parts of a corn plant left in the field after harvest, is a growing concern and opportunity for farmers in the U.S. northern and central corn belt.
While stover is important for soil health, reducing erosion and helping build organic matter, many Midwest farmers have more stover in their fields than they need and they are looking for economical options to manage the excess stover.
“In the northern climates, stover doesn’t decompose like it does in southern climates,” said Mike Edgerton, formerly quality traits and technical lead, now sugar cane lead for Monsanto. “So, for many of the farmers in Minnesota, Iowa, Wisconsin, Michigan and in northern Illinois and Indiana, stover has become a liability as corn yields increased. However, before we could justify large-scale stover harvests, we needed a simple method to understand how much stover we need to leave behind to keep the field in good shape.”
There are numerous benefits to stover in the field. It reduces wind and water erosion and adds organic matter to the soil. In turn, the organic matter enhances water and nutrient holding capacity, improves soil structure and promotes higher crop yields.
Conversely, too much stover left in the field can interfere with planting and stand establishment of the upcoming crop. Still, for the farmers to justify harvesting stover, they need a ready market for the stover and a cost effective means of removing it for use.
Researchers, industry participants and farmers collaborated to estimate rates of stover removal that maintain field health. They used conservation planning tools developed by the USDA-NRCS taking into account the soil, topography, crops, crop rotation, tillage practices and environmental concerns.
Monsanto worked closely with Archer Daniels Midland and Deere & Company to develop uses for corn stover as well as viable storage and harvesting techniques.
“The breakthrough came when researchers at ADM and several universities used a simple alkaline-processing method, similar to that used in making tortillas to upgrade the nutritional value of the stover as animal feed,” said Edgerton.
“This isn’t a new concept, cattle being fed corn stover,” said Mike Cecava, ADM director of feed technology. “What is new is being able to replace a substantial portion of the grain in cattle feed with distillers grains mixed with corn stover after we treat the harvest residues with hydrated lime or other alkaline treatments. In fact, this mixture could replace more than half of the grain in a beef cattle ration, while keeping the feed nutritious for the animal and creating a business opportunity for the corn farmer.”
Meanwhile, Monsanto is working with dozens of farmers to determine the most economical and environmentally responsible methods for collecting, transporting and processing stover and then, exploring how to expand the process on a commercial scale.
“Monsanto’s connectivity with corn farmers, technical knowledge and focus on sustainability were major contributions to the project,” said Cecava. “The challenge now is to take our research further and study the logistics of collecting and storing stover and processing it. There is still much to do.”
The use of corn stover as cattle feed could be a game changer, especially for the corn and cattle farmer. There are several avenues of profitability, as a cattle feed that can be processed right there on the farm and as a product that can be marketed to cattle farmers as a feed substitute.
As a result of this four-year project, Midwest farmers in row crop, cattle and dairy operations are conducting successful stover harvests and continuing with ongoing nutritional feeding studies.
According to publications from the University of Nebraska, when stover is sold at $80-100 per dry ton, cattlemen feeding treated stover in place of corn grain and hay are expected to achieve savings of around $20 per head at current market prices. This level of profitability is enough to shift the balance of acres allotted to corn and soybean and may bring cattle back to some farm operations.