As corn yields have increased, the amount of corn residue remaining after harvest has also increased. Managing the increasing amounts of corn residue, especially for continuous corn cropping systems, has increased the interest in harvesting a portion of corn stover. The developing cellulosic ethanol markets and increasing livestock feed costs have also contributed to this growing interest.
While some residue needs to be retained in the field to protect soil from erosion and sustain soil organic matter, removing excess residue has the potential to benefit the subsequent crop. Benefits may include improved stand establishment and early growth, reduced nitrogen immobilization, and lower disease pressure.
DuPont Pioneer is researching the effects of corn residue removal. One example is a 4-year DuPont Pioneer/University of Missouri study comparing several residue management practices in no-till continuous corn production. Results showed that removing some of the excess corn residue from a high-residue environment can provide a substantial yield advantage (Figure 1).
Another Pioneer study showed that a partial stover harvest improved the subsequent corn crop’s stand establishment after planting at 8 central Iowa locations in 2012 and 6 locations in 2013 (Figure 2). The advantage in stand establishment with partial stover harvest was greatest at 5 days after planting, but benefits were still apparent at 20 days after planting.
This study also looked at how partial stover harvest impacted yield on the subsequent crop. Partial stover harvest increased corn yield at 86% of trial locations, with an average yield gain of 4.5 bu/acre. (Figure 3). The yield increases were likely due to the improved stand establishment and availability of soil nitrogen during early growth.