Agronomy Update September 2018
Posted on September 24, 2018
MANAGEMENT
By Agronomist, Dave Dyson
The Pro Farmer Crop Tour has wrapped up, and they have released their official yield estimate for the 2018 U.S. corn crop. They have estimated the U.S. corn crop at 177.3 bushel per acre average. The USDA came out with their estimate of 181.3 bushel per acre average as of September 12th. Both of these averages are ahead of last year’s bushel per acre, making this crop potentially one of the largest in history. Big yields always create big residue issues from huge corn stalks. As you can see, I used the word “issues” not the word “problems”. This can be a “turn lemons into lemonade” situation if we take action right now, after the combines roll.
The increased tonnage of corn stover and the increased use in the soil bacterium Bacillus thuringiensis (or the Bt trait) in corn will compound next year’s residue problem. Heavy residue is tying up valuable nutrients and hosting pathogens for overwintering. A 200-bushel corn crop will produce 4.73 tons of residue. There can be 75 lbs. of nitrogen, 26 lbs. of phosphorous, and 124 lbs. of potassium tied up for more than three years if the residue is left to decompose naturally. Fungi such as anthracnose, grey leaf spot, northern leaf blight, and many of the ear rots can overwinter on corn residue.
The nutrients in crop residue are a valuable addition to a grower’s fertility program, but accessing them can be a challenging process. This year’s large harvests and high-residue continuous corn systems, as well as soybean on corn rotations, require a great deal of time and energy before nutrients are released from crop residues in the field through the natural process of decomposition. It’s important to keep in mind the primary limiting factor for residue decomposition is cooler temperatures (below 50° F), which significantly slow down the microbial activity that breaks residue down.
To help speed up the decomposition process, my suggestion is to apply 3 gal/ac of 28% UAN and 1 gal/ac of UltraMate® LQ to the corn stalks this fall, immediately after the combines roll. If we can accelerate the stalk decomposition, we can not only put more nutrients back into the soil, but we can improve seed to soil contact during planting. If you are planning to plant corn back to corn, reducing stalk residue will decrease the chances of disease overwinter on the residue.
RESEARCH
In past studies, we have found adding just a carbon source with 28% UAN can increase yield significantly (figure 1). Research indicates the rate of decomposition can be accelerated by increasing the population of stalk devouring microorganisms, something growers could affect this fall.
Figure 1: A 2015 residue management study revealed a 6 bu/A increase in soybean yield on corn stalk acres receiving an application of 28% UAN + UltraMate.
Read more about residue management in our article below.
FOR MORE INFORMATION:
Please complete the form, and we’ll get you in touch with your Territory Manager from The Andersons.
©2018 The Andersons, Inc. All rights reserved. UltraMate is a registered trademark of The Andersons, Inc.
