By Jodi DeJong-Hughes
Baled corn stalks
While corn residue is incorporated or left on the soil surface in most fields, some producers harvest the residue for use as livestock feed and bedding. How much crop residue removal is too much? Soil productivity will be reduced if all of the corn residue in a field is removed and other sources of carbon are not added. Below are important factors to consider when determining which fields and how much residue can be removed while maintaining soil organic matter levels.
Tillage
As less tillage is performed, more residue may be removed from a field. Residue removal is best suited to conservation tillage or no-till systems.
Crop rotation
As more biomass is grown, more residue can be sustainably removed. Corn grain crops produce more biomass than soybeans, small grains, edible beans, peas, potatoes, and sugar beets and are the best choice for residue removal.
Method of residue removal
Various baling methods remove different amounts of residue. Chopping the stalks, raking and baling will remove 80 percent of the residue, while baling the windrow behind the combine will only remove 50 percent of the corn residue.
When considering the economics of baling and hauling the crop residue, nutrient removal from the field should be included in the calculations. For example, a 1,200 pound bale of corn stalks would remove approximately 3.5 pounds of phosphorus, 11 pounds of nitrogen, and 19.2 pounds of potassium per acre.
While it is critical to maximize profitability from the land, short-term economics should be balanced with long-term sustainability. Consider these guidelines to maintain soil organic matter levels and protect fields against soil erosion when harvesting corn residue:
- Target corn residue harvest in fields that will be planted to corn next year.
- Rotate residue harvest among fields so that residue is not removed from the same field every year.
- Reduce tillage following residue harvest.
- To add carbon back into the soil, apply manure in addition or instead of commercial fertilizer.
- Consider planting winter cover crops. Roots from winter cover crops are extremely effective at scavenging residual soil nitrate and adding carbon to the soil.