Scouting Corn-on-Corn Acres
I’m Will Mullenix. I’m a Grower Advisor with Growers Axis® based in Iowa. My job is to provide unbiased advice to growers on all aspects of production agriculture.
Why Scouting Corn-on-Corn Acres is Important
Today I want to talk about corn-on-corn acres and why it’s important to scout late in the season.
- Why scout the acre?
- And then if you’re going to go scout, where are you going to go look?
- And then based on what you find, what do you do next?
So, first, why scout? Now we know that corn-on-corn acres are the most expensive to produce, you get more inputs, specifically nitrogen rate, you get a higher N rate there and that’s because carbon to nitrogen ratio can cause immobilization. So, you need more pounds of N on corn-on-corn acre versus a corn following soybean acre. So, what’s your nitrogen status? We also know there’s increased stress on a corn-on-corn acre versus different previous crops.
Allelopathy is the negative effects of corn residue on the developing corn crop corn seedlings. Early in the season this can be a big issue. Later in the season disease pathogens can be a bigger issue in the corn-on-corn. So, what is going on with diseases in your farm and your corn-on-corn fields?
Increased Pest Pressure
And the last thing to think about is increased pest pressure, specifically corn rootworm. Now, no matter where you’re at in the Corn Belt, whether you’re in the eastern Corn Belt and you fight western corn rootworm variant where the females lay eggs in bean fields, they don’t just stay in corn fields. Or if you’re in Iowa areas; northeast Iowa, northwest Iowa, central Iowa with extended diapause, the population a rootworm always revolves around the corn-on-corn fields. So how heavy is your rootworm pressure? And also, you spent more money on a control tactic on that acre. How did your control tactic perform? If it’s rootworm corn, is it working? If it’s insecticides, did they get you through or did you lose root mass?
Where Do You Scout?
So, you’ve decided to scout your field. The next decision is where to go scout.
Maybe you’ve got 10 fields. Maybe you’ve got 100 fields of corn-on-corn, and you only have so much time. So, imagery can be an invaluable tool to help you decide which fields to scout and which parts of fields are most important to scout.
This is a UHR image (see 2:39), its high resolution captured by fixed wing airplane passage from early August. The resolution on this image is a few centimeters. So, it’s like HDTV view. And you can see that the crop is variable. So green areas are high crop density. Red areas are low crop density. So, one of my counterparts got on the farm went to the red areas to see what was going on. And the thing he found there was extremely high rootworm adult pressure. The picture on the left (see 3:40) shows leaf scraping from beetles in the inset picture on the right. You don’t get this level of scraping unless you have a high population of adults.
So, the recommendation was to spray the field to knock down the adults because pollination was not complete.
They still had some ear tip kernel loss from the rootworm damage. But the crop wasn’t a total loss. Rootworm beetles clipping silks during pollination (see 4:10) could cause up to 50%, or on some plants 100% of the kernels to be lost. That didn’t happen on this field.
So, you decided to scout, you found the place to go look, you made a decision from what you found in those areas, and what’s next?
When you went and looked in the image that showed red areas have less crop density versus green areas of high crop density, you probably saw more stress in those red areas.
So, depending on how the growing season ends, is there more drought stress taking place? Was your nitrogen status where it needed to be since you have interferences for nitrogen availability in corn-on-corn?
All of this could affect stock quality going into the fall. So maybe it found areas that were cannibalization was present. Or maybe you found areas where there was weather damage from wind storms in the summer. These fields need to be harvested earlier.
Scouting: Informed Decisions = Increased ROI
And so, adjusting your harvest order based on a late summer scouting pass can help increase the bushels in the bin this fall.
Hey, thanks for watching. And if you want to learn more about imagery, go to our website, Growers Axis.com under Insights. I’ve got a video there on imagery types. If you want to understand better how to get started with our services, check out my video on how we build a crop budget, understanding your cost of production and how that impacts your ROI.
If you want to talk with me personally, give me a call. My number is 309-824-1755
And, thanks again.