Alternative uses of corn residue for various purposes, such as baling the residue for livestock use or for cellulosic ethanol production, needs to be approached carefully. Removal of too much crop residue potentially can have adverse effects on soil and water quality.
How much corn residue can be safely removed from a field? Sustainable stover removal rates depend on several factors such as soil erodibility, surface slope, cultural practices and climate conditions. Recent studies suggest that only 20 to 30 percent of the total stover production could be removed for biofuel, based on ground cover requirements to control soil erosion. However, other studies suggest that residue removal should be lower than 20 percent, especially with conventional tillage, in order to maintain soil quality and nutrient cycling for long-term soil productivity.
Consider long-term effects of residue removal
The impact of crop residue removal on soil productivity and environmental quality is not a short-term outcome, particularly in the Midwest, where high organic matter, high soil productivity and good agriculture production conditions mask the short-term effect of residue removal.
Possible short-term impacts of corn stover removal may include an increase in amount of nitrogen, phosphorus, potassium, calcium, magnesium and other nutrients that need to be applied to replace these nutrients lost due to crop residue removal. Potential deficiencies of nutrients and decline of organic matter in the soil are both the long-term impacts. It was estimated that nutrients replacement cost due to corn residue removal was approximately $20 per ton of removed corn residue. These nutrients will be permanently lost from the soil system nutrients pool due to lack of replenishment from crop residue and they have to be added to maintain soil productivity.
Keep in mind that when you harvest corn crop residue from a field, a significant amount of carbon, nitrogen, phosphorus and potassium is removed. Using no-till and above agronomic nitrogen fertilizer rate may help in reducing soil organic matter loss in the short-term due to crop residue removal.
• What else do you remove when you harvest corn crop residue from a field?
• A significant amount of carbon, nitrogen, phosphorus and potassium is removed.
• Using no-till and adequate N application rates may minimize soil organic matter loss due to residue removal in the short-term.