Corn and soybean stands in central Illinois are off to a great start this season, with just a handful of exceptions.
“These corn and soybean crops have established strong foundations and are some of the best stands we’ve seen,” says Ken Ferrie, Farm Journal Field Agronomist “Yes, there are some exceptions out there, but overall, we’re really pumped by what we’re seeing.”
Ferrie is telling farmers to check corn and soybean crops now and determine whether they need to bump up their yield goals and then supply them with adequate nutrients to support their potential.
This is especially important for corn in those fields where nitrate tests indicate nitrogen (N) was lost due to too much moisture. “Fall-applied N and spring N use showed losses,” Ferrie says. “We could tell the higher rain amount areas by the nitrate levels as they came in. I know nitrate testing is a hard chore, but it’s well worth it in years like this, where yield potential is very strong.”
In this week’s Boots In The Field podcast, Ferrie reviews four additional agronomic problems and offers some steps you can take now to give corn and soybean crops an added boost.
1. Rootless Corn Syndrome
Some farmers are currently dealing with corn that is getting floppy and wanting to lean or tip over. The problem, called rootless corn syndrome, is usually observed in corn plants from about the three- to eight-leaf stage of development.
Ferrie says this problem can be contributed to one factor or a combination of several factors, including: sidewall smearing that was caused by planting into soil that was too wet and/or where too much downforce was used on the row unit. Another potential cause is strip-tilling on sloping ground that resulted in erosion issues.
Where sidewall smearing is the main contributing factor, the corn crop is in rapid growth. The crop likely was able to produce the first three sets of roots, but they went straight down and then out due to sidewall smearing. Now, the crop is struggling to get the fourth and fifth set of crown roots developed which would anchor the plants.
This issue is being exacerbated this week, due to hot, soil-drying weather conditions which will cause the ground to start to crack open. There are a couple of things you can do in this situation.
“One, try to not apply a growth regulator to the crop, like 2,4-D or dicamba, if you can help it,” Ferrie says.
Second, and the main fix, is to roll soil around the base of the plants, he advises.
This practice will usually take two passes with a row-crop cultivator (not a field cultivator) – one shallow pass to create some loose soil and then a second pass slightly deeper with the shields up and using a faster speed to roll the soil at the base of the plant to cover up the slot and stimulate the brace roots to fire off.
“Timing is crucial – you’ll need to get this done before the plants get so big that they start falling over,” Ferrie says. “You might ask a neighbor who grows organic crops to get some pointers on this. They do it all the time for weed control in the row.”
In a handful of fields, the problem of rootless corn syndrome is soil-type related, due to soil moisture levels at planting.
“So again, you may have to drive every pass of the field setting that cultivator down when you need to, and picking it up when you don’t need it,” Ferrie says.
2. Count The Collars
As the corn crop transitions from relying on the seed roots and the seed starches to the true roots, Ferrie is seeing some ununiform stands. He advises getting out into fields to count collars to determine what might be happening to cause uneven stands.
“As we scout these corn stands, count the number of leaf collars showing on the plants,” he says. “If collar counts between plants are the same, even if some plants are smaller, that means the plants are all the same age. They germinated and emerged at the same time, but there’s something affecting their growth.
“If they’re not the same collar, now you have an emergence problem. So you’re going to think back about the seed depth and furrow conditions at planting, and this could also translate to seed quality in those early planted cornfields,” he says.
Another value from counting collars is the information can guide your post-emergence herbicide applications so you spray herbicides at the optimum labeled rates.
3. Tar Spot Sightings
Some farmers have told Ferrie they have identified tar spot in their cornfields. While this is early for the disease to show up, it’s not unheard of in wet fields. Tar spot lesions could be present on lower leaves.
“If you see potential tar spot lesions on those lower leaves, give them a good rubbing and see if that spot comes off,” he advises. “If it doesn’t come off, it’s probably tar spot and those early infections will need you to be more aggressive with the treatment plan.”
4. Waterhemp Worries
One of Ferrie’s bigger concerns this year is the amount of waterhemp that is breaking through early-season herbicides applied in corn.
“I think this year we’re going to have pressure like the growers in Tennessee have been dealing with for some time,” he says. “When waterhemp in the corn is so thick that it’s messing with your Y-drop application, you have pressure that most likely won’t be controlled.”
On the soybean side, Ferrie says to be timely with post herbicide applications even if your soybean crop growth is stalled due to the carbon penalty.
“The good news is beans going through the carbon penalty don’t seem to be affected much because so much of their yield is made later in the growing season,” he says.
“Some guys are asking, ‘The beans seem to be stalled, should we wait to apply our herbicide?’ The answer here would be no. Apply your herbicide based on weed heights. Don’t be overly concerned about your soybeans. They’ll come out of the carbon penalty and do fine. Get those weeds controlled.”
Listen to the complete Boots In The Field podcast here:
How to Time Fungicide Applications To Best Tackle Tar Spot
Georgia Farmer Reaps Bigger Yields By Focusing On Better Acres
