Considerations for harvesting stalklage

By Dr. Matt Digman and Dr. Kevin Shinners, University of Wisconsin-Madison Department of Biological Systems Engineering
Corn residue, or stover, is often harvested as dry bales for roughage feed or bedding.  However, the window of opportunity for drying is limited by short autumn days and low temperatures.  An alternative harvest method is to chop and ensile stover as stalklage.  In addition to being able to harvest and store at higher moisture levels, stalklage is more palatable and is easier to integrate into a TMR feeding system, and successfully preserving stalklage is not very different from making good haylage or corn silage.

It is critical to harvest stalklage with sufficient moisture levels for good packing and proper fermentation.  Ideally, stalklage should have moisture levels in the mid-60% range.  A rule of thumb is that stover moisture is roughly twice that of grain moisture, but it is still important to measure stover moisture using a microwave or forced air dryer.  Stover moisture is primarily located in the bottom half of the stalk, so using a windrow stalk shredder is a good approach for harvest.  Chopping and shredding the crop too low can result in unwanted soil contamination, which can increase harvester wear and displace nutrients in the animal’s diet.  When chopping the windrows, set the harvester’s windrow pick-up to have more ground clearance than you would when harvesting haylage.  Be aware that nitrates are usually concentrated in the bottom third of the stalk.  The fermentation process will usually reduce stalklage nitrate content, but this requires a complete fermentation cycle ideally more than 60 days before feeding.  The best practice would be to test your stalklage for nitrates before feeding.

Shredded stover can dry quickly, so be prepared to chop soon after forming windrows.  Even when best practices are followed, stover can be drier than ideal.  Although you may be tempted to add water, that’s not a practical solution.  It would take more than 50 gallons of water to bring 1 ton of stalklage from 57% to 65% moisture, and stover also does not absorb water very well.  A better approach is to blend a wetter material with the stalklage, such as fresh alfalfa or forage sorghum.  Yet this approach can be a logistical challenge. To bring 2 tons of stalklage from 57% to 63% moisture would require blending 1 ton of alfalfa at 75% moisture.  Clearly, the best approach is to utilize harvesting practices that target stalklage moisture in the mid-60% range, such as after high moisture shelled corn.

Stalklage is often ragged and difficult to pack to minimize oxygen in the silage, so it is good practice to harvest at a shorter length of cut setting than you would with corn silage.  If it is more finely chopped, you may find it better to store this material in a bag rather than a bunker silo.

With these basic considerations, stalklage can be a good alternative to baled stover.  For the best results, start harvest early in the season or include the bottom stalk to ensure proper moisture for fermentation, chop at a shorter length of cut, avoid soil contamination, store for at least 60 days, and test for nitrates before feeding.