Editor’s note: The following was written by John Wilson, University of Nebraska Extension educator, for the university’s Crop Watch website April 19.
Without a doubt, the question of what to do with cornstalks that accumulated almost everywhere has been one of the most frequent questions following the March flooding.
Cornstalk accumulations have varied from a few inches to a few feet deep. This has and continues to pose a challenge for many farmers as they prepare for spring fieldwork and planting.
If the layer of stalks isn’t too deep — 4 inches or less — they can be incorporated into the soil with tillage. One word of caution: The soil underneath a layer of cornstalks will dry even slower than fields without the extra crop residue.
Doing tillage or other field work before the soil has dried can cause compaction and create ruts, resulting in a greater problem than originally created by the stalks.
If the layer of stalks is greater than 4 inches, and unfortunately most of them are, there aren’t a lot of good options. The stalks can be burned, spread, composted or stockpiled for spreading at a later time, probably after harvest this fall.
Burning may be the easiest method if they dry out enough. When burning, always remember to consider where the fire can travel and get a burn permit from the fire department.
Spreading is an option if the stalks aren’t too deep and you have the equipment to do this. Once you spread them, they will dry faster and you can either burn them or incorporate them into the soil.
One thing that is important to remember any time you incorporate organic material into the soil, cornstalks and similar debris are high in carbon content and low in nitrogen. The microbes in the soil need nitrogen to break down the carbon-based materials and will take residual nitrogen from the soil to aid in this process. In doing so, they may create a temporary nitrogen deficiency for crops that were planted. You may need to increase your nitrogen fertilizer rate to offset this tie-up of nitrogen in the soil.
Composting cornstalks is not the same as piling them in a corner of the field. To compost cornstalks, you will need to turn and mix them periodically, maybe once a month over the summer. This will increase the rate they break down.
You might form a big windrow of stalks along the edge of a field with enough room to turn and mix the stalks with a loader, lifting and pushing the windrow over onto adjacent new ground. The next time repeat the process and move the windrow back on the original ground.
Stockpiling cornstalks in a pile at the edge of the field will allow for some breakdown to occur, but the rate will be slower than if they were mixed and composted. Stockpiling will take the least ground out of production. Then at a later date — probably this fall after harvest — you can spread the stalks on the field in a layer thin enough that it won’t cause problems with fieldwork or planting the following year.
Unfortunately there is not a great option for dealing with cornstalks that accumulated because of the flooding in March. You will need to assess the amount of cornstalks and the equipment you have available to determine which option will work best for you to manage them on your farm.