Locally there is a considerable investment being made into labor force, technology, and infrastructure needed for effective use of total corn plant biomass as a feed source. This provides a new opportunity for potential revenue streams and a considerable amount of investment going into some of our local communities.
When I start to think about it, the question of whether or not you should remove some of your stover from the field boils down to the next three questions:
1) What are the advantages and disadvantages to stover removal as it applies to each field?
2) What is the nutrient removal when different corn plant components are harvested?
3) What factors need to be considered to protect soil quality?
Pros and Cons of Stover Harvest
The advantages of stover removal come at the frontend of the next year’s crop setting us up for potentially higher yields. Stover reduction will decrease the amount of residue in the field and improve the plantability of our soil and reduce the need for multiple tillage passes to properly size and incorporate residue into the soil. A reduction in the depth of corn residue will also allow for a more even warming and drying of the soil aiding in seed germination and even emergence of your corn seedlings. Corn residue also has an allelopathy affect and combined with immobilization of Nitrogen we will get more vigor and better root development early in the plants life cycle. A reduction in corn residue will also help us in fields where we have bacterial and fungal diseases that overwinter on the residue itself.
Most of the disadvantages are easily managed through proper field selection and planning, stover removal is not right for every acre, so we need to be mindful in selection. Excessive removal will expose the soil to erosion risks, a reduction in a much needed carbon source for soil health and organic matter, and a reduction of infiltration rates on some of our more fine textured soils. The harvesting operation itself presents some challenges in an already condensed schedule in the fall and poses some compaction risks with extra trips across the field.
There is a considerable amount of nutrients to be removed mostly in N, P, K, Mg and S that will have to be replaced immediately to ensure no reduction of yield in the following year. In a 240-bushel corn crop, we could safely remove about 2.2 tons per acre of residue on selected acres. In that 2.2 tons per acre, we would account for 35.2 lbs of N, 13 lbs. of P, 44 lbs. K, 5lbs of Mg, and 6 lbs. of S. When we add these removal rates into a dry program it will about $28.00 at today’s fertilizer prices. So when it comes to deciding what to do about removing your stover, here is the best answer I can give you. If the stover is being purchased, I would say you can easily add a 7-10 bushel yield response to your fields because of our increased emergence and early vigor. So, if you are selling that residue, add the yield increase to the top of it, then remove the added fertilizer costs and about another $25-$30 for the addition of cover crops to protect your soil and help maintain its soil health. I truly think if your decision is well thought out, that the removal of stover on selected acres is advantageous even above the added costs and management considerations. The trick is selecting the right acres, and when you are ready to make that decision, just call, Central Valley Ag would be glad to help.