As every growing season comes and goes, farmers learn more about growing higher yielding crops. Moreover, they are always trying to figure out how to improve or adjust for the next growing season. Residue management is something that can have a lasting effect on the current crop, but more importantly future crops.
What Value Does My Residue Have?
All crop residue contains large amounts of essential nutrients for crop development. For example, a 200 bushel/acre corn crop contains approximately 168 pounds K2O/acre. Very little potassium is removed from a corn field after shelling corn. Most potassium for a corn crop is housed in the leaves, stalks, tassel, cob, and husk. The University of Illinois Crop Physiology Laboratory provides more information on all nutrient uptake and partitioning for both corn and soybeans here.
Why Manage Residue?
Managing residue will speed up the process for quicker nutrient availability from the crop residue. For example, residue management, that crushes or ruptures the corn stalks which allows water to run over and through the stalks can flush potassium out of the stalks, restoring it to the soil. This is something to consider when considering fertilizer programs for both corn and soybeans. We know that soybeans will take up a lot of potassium.
Additionally, crop residue, specifically corn residue, can harbor different harmful diseases and insects that provide a place for these pests to overwinter that can be detrimental to a soybean crop. An advantage of managing residue can be limiting places for these pests to overwinter.
What Management Practices Can I Implement?
The challenges that farmers face with managing residue is how to be efficient with this process. Ideally, residue management is done in the fall so there is adequate time for residue breakdown before planting the next spring. No matter the form of residue management, warm, moist conditions are always ideal as this is when the microbes will be most active. Residue management can be broken down into two categories: chemical and mechanical. Those are as follows:
Chemical: Numerous chemical products are available in the marketplace to aid in residue breakdown. Beck’s Hybrids has two products that are Practical Farm Research (PFR) Proven. These products were tested in a corn-on-corn rotation and applied in the fall after harvest. The first is RES PLUS from Elemental Enzymes which is labeled to have macro and micronutrients combined with a residue degradation booster. Across three years, there was an 8.7 bushel/acre and $31/acre advantage. The second is ROBUST from Rosen’s Inc. which is labeled to have some sulfur, manganese, and zinc to help feed the microbes. Across three years, there was a 6 bushel/acre and $12/acre advantage. With large advantages in a corn-on-corn system, I expect there to be a large return in soybeans. Challenges with products like these may be logistics as most farmers may not be operating their sprayer in the fall. These products can be added to a pesticide application if compatible. Always read the label.
Mechanical: Tillage and attachments for corn heads are some of the most popular forms of mechanical residue management. Tillage does an excellent job of sizing residue and incorporating it into the soil. However, tillage may leave soil more susceptible to erosion. A great way farmers can maximize their combine pass by not only harvesting but also managing residue is with their corn head. Residue management with a corn head varies from things such as stalk stompers to chopping corn heads to different snapping rolls. Beck’s PFR program saw a 2.3 bushel/acre advantage in soybeans across three years when utilizing a Capello Quasar Chopping Head. A chopping head does an excellent job of making smaller pieces of residue. Small residue has more surface area for microbes to feed on which results in faster breakdown of residue.
For no-till farmers, managing residue with a corn head is one of the best forms of residue management. If some no-till farmers are running their sprayer in the fall, they may also look at some chemical forms of residue management. Just keep in mind, that warm, moist conditions are ideal for those products because that is when the microbes will be most active.
Conclusion: Residue management is something that can provide a lot of value to future crops. In a corn-soybean rotation, we know that a 200 bushel/acre corn crop has a large amount of residue that contains a lot of nutrients, but also can contain a lot of harmful diseases and insects. Breaking the residue down to eliminate a host for these harmful diseases and insects while restoring nutrients to the soil can lead to a successful soybean crop.