Once considered low-quality forage of little value, corn stover is now thought of as an under-used resource and utilizing it is a growing practice in the cattle-feeding industry.
However, as the popularity of utilizing corn residue as a feedstuff grows, many warn farmers must be careful to remove or graze residue in a sustainable manner.
Galen Erickson, professor and beef feedlot extension specialist at the University of Nebraska-Lincoln, stressed the importance of corn residue for the beef industry.
“With more and more acres planted to corn, and less and less pastures and traditional forages, the only forage resource that is increasing for beef cattle is corn residue,” he said.
With about 80% of the feed used in the beef industry being forage-based, producers must focus on how to improve use of forage and make that more economical, he said.
“That’s why we are focused on corn residue. We believe it’s the most underused resource we have,” Erickson said.
Some parts of corn residue are unpalatable and cattle prefer certain portions over others.
Jim C. MacDonald, associate professor of ruminant nutrition at the University of Nebraska-Lincoln, said cattle will eat the husk and leaf very readily, and both those components are the most digestible. The husk has a digestibility of about 70%, which is similar to that of spring grass.
“It’s amazing how digestible the husk is,” he said. “The problem is there’s not very many husks in the field.”
Cattle will first eat all the husks in a field, then the leaves. After that, the rest of the palatability and digestibility of the residues (cobs and stems) goes down substantially.
SUSTAINABILITY IS KEY
Erickson said feeding corn residue must be a sustainable practice. Producers need to be careful not to comprise fields by removing too much organic matter, so that the loss of cover does not result in soil erosion or water loss.
MacDonald stressed that not all corn residue should be removed from the field to reduce erosion potential. The amount of residue removed depends on soil type, topography of fields and rainfall amounts.
“The biggest issue is erosion potential. You don’t want bare soil out there,” he said. “A secondary issue might be the nutrients you are removing, but then again, you’re presumably being paid for those nutrients if you’re selling the residue.”
Farmers may want to leave more residue on fields with a lot of run-off potential. But sometimes, it is actually beneficial to remove the residue because it can result in earlier and greater emergence, he said.
“Some long-term trials in eastern Nebraska show a two-bushel-per-acre increase in subsequent soybean yields in a corn/soybean rotation when you graze the residue,” he said. “In really high-yielding fields, there’s so much residue there it’s hard for the plant to come through.”
A new company based in Gretna, Nebraska, is also a believer in removing residue in a sustainable manner.
Pellet Technology USA, LLC (PTUSA) is making plans to build bioprocessing facilities across the Midwest to produce a newly developed pelleted product made from treated corn stover, corn syrup and distillers grains. PTUSA has partnered with MacDonald and other UNL researchers on finishing steers with its new pelleted feed product.
Company founder and Chief Operating Officer Russ Zeeck said PTUSA has a distinctive sustainability program that growers who want to sell stover to the company must utilize for soil health. The company has developed specific harvesting protocols, from timing and equipment, to testing before and after harvest, to various management practices for soil and fields.
Farmers can choose whether to harvest the stover themselves according to the grower harvest program, or if they don’t have sufficient labor available, the company will come in and harvest the stover for them.
The company takes great care as to how much stover is removed from the field.
“Depending on the soil types of the field, the slopes of the field, and other characteristics of the field, you can have the exact same soil, but you’re going to take different levels of residue off,” said Joe Luna, manager of business strategy for PTUSA. “Nitrogen and phosphorus are key elements, but maintaining the organic matter in the soil and preventing erosions are also important factors.”
The higher the bushel production of corn per acre a field has, the higher the amount of residue that can be taken from the field, according to MacDonald. For instance, a 250-bushel yield would produce a lot more residue than a 150-bushel yield.
He added that irrigated fields in western Nebraska bring good yields and the stover is more fully utilized. The underutilized residue is found more in eastern Nebraska and into Iowa and the rest of the Corn Belt.
“That’s where a processing facility makes more sense. Because once you pellet the residue, you can afford to haul it longer distances compared to hauling a corn residue bale, which is not very dense and may fall apart,” he said. “So it helps with transportation issues as well.”
NEW HARVESTING TECHNOLOGY
MacDonald added that new harvesting technologies now allow producers to better select for different components. For instance, John Deere has a single-path system that gets the leaf and husk, and quite a bit of cob, he said.
“The cob’s OK as long as it’s ground so cattle can’t sort it out,” he said. “Putting cobs into a pelleted process where it’s all treated and ground finely works pretty well.”
New Holland also has a corn rower that cuts off different numbers of stalks and chops it up into a windrow. Increasing the proportion of husks and leaves relative to cobs and stems improves the feeding value of the residue, he said.