Update from the Field: Degrade Your Stalks, Not Your Pocket Book
Posted by Dave Dyson, Agronomist on November 07, 2018
This post may reference products and/or services only available to our Retail Farm Center customers. For more information contact your Territory Manager at The Andersons.
A couple of months ago, I wrote about the up and coming corn crop’s huge yield and highlighted all the corn stover that was going to accompany this crop. To the delight of the farmers, the huge corn yields did arrive, and as previously predicted, so did the increase in residue.
When stalks come in contact with the soil, soil microorganisms go to work on degrading this residue. Bacteria in the soil exist on a simple diet, and their “meat and potatoes” are carbon and nitrogen. The soil bacteria want them in a particular ratio, ranging from 5 to 11 parts carbon to 1 part nitrogen. Most of the crop residues returned to the soil have a high carbon to nitrogen ratio - more carbon and less nitrogen. So, when the microbes begin to feast on the residues, their carbon diet will be fed, but in the process they will need to feed on nitrogen to balance out their ration. Thus, when eating on carbon, the microbes temporarily tie up available nitrogen. This process is called nitrogen immobilization. The higher or wider the carbon to nitrogen ratio, the higher the immobilization of nitrogen. The nitrogen is not tied up or immobilized forever. It will be released back to the soil upon the death of the soil microbes in a process called mineralization.
All crop residue is not created equal, as carbon to nitrogen ratios vary based on the crop type. Alfalfa, soybean, and other legumes generally have lower carbon to nitrogen ratios. When ratios are under 20:1, a quicker mineralization usually occurs. Corn has a higher carbon to nitrogen ratio (70:1) than soybeans. Crop residues with higher carbon to nitrogen ratios take more time to decay and result in higher amounts of nitrogen being required by the microbes to decompose residues. To balance the carbon to nitrogen ratio, the bacteria need extra nitrogen. Unfortunately, this leads bacteria to compete and rob nitrogen from the crop. This can result in a temporary shortage of nitrogen in the soil, and may result in negative impacts to the following season’s crop.
We can jumpstart corn stalk degradation by spraying 3 gal/ac of 28% and 1 gal/ac of UltraMate® LQ with at least 15 gal/ac of water to ensure coverage. The left side of figure 1 (below) shows a darker color where UltraMate LQ and 28% was applied, suggesting these stalks are breaking down faster. Nutrients in this section of the field will be available sooner for next year’s crop, and equipment will be able to move through the stalks easier during planting. If you are interested in breaking down your residue faster, contact me or your local representative from The Andersons.
Figure 1: This picture was taken outside of Walton, IN, on 10/15/18. On the left, the corn stalks were treated with 1 gal/ac of UltraMate LQ and 3 gal/ac of 28% on 9/27/18. The corn stalks on the right were untreated. The treated area appears darker in color, suggesting these stalks are breaking down faster due to the UltraMate LQ and 28% application
For more information on residue management and product alternatives, see our Residue Management technical bulletin.
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Dave Dyson is a regional agronomist for The Andersons’ Farm Centers which are located throughout Ohio, Michigan, and Indiana. He is an Indiana native and grew up on a dairy farm in Miami County. A graduate of Purdue University with a degree in Crop & Soil Science, Dave has a deep knowledge of various agronomic topics and is committed to helping growers improve their crops. If you have any questions, Dave can be reached at david_dyson@andersonsinc.com.
UltraMate LQ is a registered trademark of The Andersons, Inc.
