October 16th, 2020
by Andrew Blomme on 10/16/2020
Week of October 16, 2020
It has been a busy couple of weeks for Herbers Seed as we gear towards 2021. This week's newsletter will cover some observations from the fields and Lou has an update on the upcoming fall ammonia season.
Notes from the Field
This summer, I spent a good portion on my time digging up plant roots. With the lack of rainfall this year, issues that resolve themselves in a normal year have reared their ugly heads. The two most common problems I saw throughout the summer that are still effecting the crop today are tomahawk roots from sidewall compaction and pancake roots from sub-surface compaction. The picture below was taken in July and show both of these challenges.
Pancake roots occur when there is a layer of very compacted soil several inches below the surface. Roots penetrating down into the soil are unable to dig through this very hard layer of soil and instead shoot outward. Pancake roots lead to standability issues and root lodging, especially late in the season. The picture below shows pancake roots that was dug up earlier this week. As you can see, roots only penetrated a few inches into the ground.
Sidewall compaction has also been a prevalent issue throughout the year. The picture below shows a root system that was limited by sidewall compaction all season. The plant is oriented as if you were looking right down the furrow. The left side of the picture was the more compacted sidewall and you can see the limited root growth on that side compared to the right side.
On the tail end of a dry year, these problems above may create some standability challenges. Consistent rainfall in June and July would have gone a long ways in erasing these issues, but this year we are having to face them head on.
Fall Applied Ammonia -by Lou Herbers
Fall ammonia season has historically started around November 1 in this geography. We like to see the 4” soil temperature at 50 degrees and cooling. You can follow the 4” soil temperature by clicking on the link below.
Iowa State Extension-4" Soil Temperatures
Looking ahead, temperatures for the next two weeks are forecast to be below normal. We are tentatively planning to start custom ammonia application on Monday, October 26th. We will continue to monitor the extended forecast over the next 10 days. If the temperature forecast is normal to below this will give us confidence that soil temperatures will remain cool. If a warmup is forecast, we will delay the start date.
I have heard many comments about the soil being too dry for fall ammonia application. I think these concerns are largely unfounded and that there is adequate soil water in the top 8 inches of the profile for the ammonia to convert to ammonium and then attach to the soil. A bigger concern would be the hardness of the soil and the ability to seal the trench due to hard, cloddy conditions. From what I have seen of banded dry applications and manure applications so far this fall, the soil appears to be in pretty good shape and ammonia application should work well. Some years we fight compaction that occurred when soybeans were combined in wet conditions. This fall has been just the opposite. Overall, I expect very good conditions for fall ammonia application. Below are links to a couple articles discussing ammonia application into dry soils.
Iowa State ICM-Anhydrous Ammonia Application in Dry Soil
Illinios University-Are Soils Too Dry for Anhydrous Ammonia?
For those who would like to use a nitrogen stabilizer we will be offering Centuro through the custom applied rigs. Centuro is a relatively new product from Koch that has much improved handling characteristics compared to N-Serve. The mode of action is exactly the same as N-serve. They both inhibit the Nitrosomonas bacteria that convert ammonium to nitrite. Some soil types in our area tend to be more prone to nitrogen loss because they have a higher clay content and have poorer internal drainage. Examples would be the glacial till soils on the sidehills (i.e.: Shelby Adair complex) or tighter bottom soils (i.e.: Zook & Wabash). We have the ability to write prescriptions to inject stabilizer when applying on those soil types. If interested in this type of application, please contact Michael so that Rx’s can be written ahead of time.