Population counts and observations of this year’s corn crop can help inform next year’s planting
By Jackie Clark
Taking a closer look at your corn fields between emergence and knee-high can provide some valuable information, according to field crop experts at the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA).
Calculating population and other observations can give farmers information about their planting setup and early season stressors that may help to improve for next season.
One of the most obvious places to start are any places where you see gaps in your corn stand.
“If you’ve got gaps in your field and the population was lower than what you thought, the first thing I’d do is confirm if there’s actually seed or not in those gaps,” Ben Rosser, OMAFRA corn specialist, told Farms.com. “If you’re digging in those gaps and you can’t find seed and you’re confident that you’ve searched well and can’t find anything at all, then you’re thinking it was probably some type of seed placement issue.”
In that case, correcting the problem may involve fixing a metering problem or other planter mechanical adjustment.
“If you’re digging in those gaps and you do find seed, then that’s when you’ve got to start figuring out why,” Rosser said. “What does it look like? Did it try to grow, did it try to germinate and leaf out? Is there root burn?”
Depending on the answers to those questions, the seeds may not have grown properly because of a variety of reasons, including lack of moisture, fertilizer burn, inappropriate planting depth, or low pH, he explained.
“If we had had really pounding rains after planting … you could see some crusting in the field and plants could be having a hard time coming up,” he added. Or, “if you planted just ahead of some cold weather or cold rains, maybe it was a bigger issue or a hybrid that just wasn’t tolerant to early stress if you had planted early.”
Thinking critically about what could be contributing to germination issues can help producers improve next year, Rosser said.
You may also want to dig up some plants from different parts of the field to gather some more information.
“The best time would be sometime shortly after emergence, maybe to knee high corn stage,” Rosser explained. Even if the corn is a little older, around V4-V6 stage, you may be able to identify some larger challenges.
“If you wait a little bit later, if there’s issues due to compaction and stuff like that, a lot of those issues show up later, once you start to get nodal roots set, that’s when you can start to see some big differences in plants,” he said.
“You can dig some plants, if there is fertilizer burn going on in the seedling roots or pest issues, you’ll still be able to see those,” he added. Digging lets you take a close look at plant roots and the furrow condition to get an idea of any mechanical or agronomic issues.
Farmers can also check planting depth by digging up plants.
“You’ll still see where the seed is, and you can measure the difference between the seed and ground level. It’s pretty easy, and it’s a good thing to do just to get an idea if you were placing the seed at the depth you thought you were,” Rosser said. “Even if the seed coat is no longer visible, when you look underneath those big massive, nodal roots, you should still see the mesocotyl, and that’s between the seed and where the nodal roots set.”
If farmers are finding planting depth is highly variable in different sections of the field, that may also provide an opportunity to further optimize planting equipment for next year.
Variable planting depth could be a result of “not getting good seed-to-soil contact, not getting the seed to the bottom of the trench firmly into moisture. Also, if there’s some bounce in the trench or you’ve got worn out discs and the trench isn’t forming a pointed bottom,” Rosser explained.
Insufficient down pressure in row units can lead to shallower planting in tighter, more compacted parts of the field, he added.
Inconsistent planting depth is “especially an issue when those shallow ones become too shallow to germinate,” he said. “Either you’ve got some gaps because those seeds did nothing, or they germinated later and you’ve got a lot of plant-to-plant variability.”
That variability may also “depend on the uniformity of moisture in the soil profile as well,” he added.
Depending on tillage practices, the seedbed can have variable moisture, which can also lead to inconsistency with planting depth and emergence, Rosser explained.
Click here for more information from OMAFRA on what information from your current corn stand could be telling you.