Before deciding whether or not to bale some of your cornstalks, weigh the costs against their potential value as a livestock feed, suggests Bruce Anderson, University of Nebraska Extension forage agronomist.
At current fertilizer prices, stalks contain about $12-13 worth of nitrogen, phosphate, sulfur and lime per ton, says Anderson. The value of those nutrients should be considered because they may need to be replaced with extra fertilizer.
Cornstalk removal also can reduce soil organic matter, increase erosion risk and increase soil water evaporation. Nebraska research shows that dryland corn yield declines about 2 bu/acre for each ton of residue removed while irrigation costs increase similarly to maintain corn yield. Labor and equipment costs average $20-25/ton and baling stalks tends to cause more wear and tear on equipment than other baling operations.
“Totaled together, these costs amount to $50-55/ton of cornstalks removed,” he says.
One rule of thumb suggests that cornstalks’ feeding value is midway between that of straw and prairie hay. But their feed value varies greatly. For example, if everything is baled they may be only 3-4% protein and less than 50% TDN. Harvest just the tailings and two or three rows behind the combine and TDN increases to the lower 50s and protein to about 5%. But you should have the stalks tested to make sure.
“Are baled cornstalks worthwhile?” Anderson asks. “These numbers suggest they are if you can sell them for over $60/ton or buy them for less $40/ton. In between, it’s going to depend a lot on your individual ability to either cut costs or feed efficiently.”