There has been a lot of interest in utilizing corn stover for feed or bedding this year, especially in some of the drier areas of the province. Corn stalks can present a challenge to deal with in a cropping system and while there are many ways to handle the corn stover, the solution for each farm is going to be different. For farms with livestock, or neighbours with livestock, grazing or mechanically harvesting the stover can be an option. There are many benefits to grazing and removing corn stover but there are also costs associated with removing the corn stover that need to be taken into account.

Grazing corn stover can be an excellent way to manage corn residue. The cattle will digest the corn stover and break it down, while leaving almost all of the nutrients in the field and increasing their availability to the following crop. Grazing stover can be done relatively easily with some electric fence, a water supply and a mineral tub. Depending on the cattle being grazed and the quality of the stover, supplementing with hay or a protein source may or may not be necessary. Corn stover is best suited as a feed for 2nd trimester beef cows and one acre of corn stover will typically provide one cow with enough feed for 1-2 months. The Total Digestible Nutrients (TDN) in corn stover is typically around 70% following harvest and then dropping to 40% TDN over time. This is partially due to leaching of nutrients, but also because the cattle will eat the highest quality leaves and grain first. If there is a lot of grain in the field, either on the ground or small cobs that the combine did not pick up, it may be necessary to restrict grazing to prevent grain overload. The animals can either be restricted to a certain time in the field, or they can be strip grazed. Strip grazing the field will keep the energy content of the diet more uniform over time. Once the animals have eaten most of the leaves and cobs in the field, it will likely be time to start supplementing with hay and/or protein. Body condition and fecal scores should be monitored while grazing to ensure the animals are not losing condition.

Corn stover can be baled for either feed or bedding (Figure 1). When baling corn stover, organic matter and fertility will be removed from the field and the soil will be more exposed. In order to protect the soil health and prevent erosion, there should be a minimum of 30% ground cover after baling. If the corn stover will be reapplied to the field as compost/manure, then the loss of fertility and organic matter may not be an issue. However, if the manure is constantly being applied elsewhere, or the stover is sold off-farm, fertility will drop quickly if it is not managed. Harvesting stover puts more wear and tear on equipment than it does with other forage and straw crops and this needs to be taken into account. When harvesting the stalks, they are generally mowed or chopped, raked and then baled when they are dry.

Bales of corn stalks.
Figure 1. Bales of corn stalks.

According to the International Plant Nutrient Institute, 1 metric tonne of corn stover contains 18 lbs (8 kg) of nitrogen, 6.5 lbs (3 kg) of phosphorous and 44 lbs (20 kg) of potassium on a dry matter basis. Using prices of 54 cents/lb for nitrogen, 55 cents/lb for phosphorous and 37 cents/lb for potassium, the corn stover would be worth $31.84/MT dry matter. On top of the base fertility the corn stover will also be removing valuable organic matter and residue cover which needs to be taken into account when setting a price. After harvest, if there is less than 30% residue cover, the field will be at an increased risk of erosion. If the stover is to be harvested, then the cost of chopping, raking, baling and transporting the stover must be calculated. Corn stover can be an economical source of feed and bedding, and managing it correctly can improve crop yields as well, but it is not 'free' and needs to be managed correctly to benefit both the livestock and the cropland.