Weather extremes put a lot of stress on this year's corn crop, and that's causing stalk quality to deteriorate quickly this fall, says Mark Johnson, Iowa State University Extension crop specialist. Much of the crop was planted in wet conditions, which hindered root development and limited nutrient uptake. Then exceedingly hot, dry weather during the grain fill period further decimated stalk quality.
He is advising farmers to scout fields now to check condition of stalks and prioritize harvest in fields where problems are noted. "There are getting to be a lot of problems out there," he says. "Even where there isn't stalk rot, the plant is doing everything it can to feed the ear, so it's cannibalizing that stalk. I've been in fields where the stalks don't have any stalk rot, but you can still pinch them and find they are very, very depleted."
This summer's dry, hot growing conditions have weakened corn stalks
This year's erratic growing conditions have weakened the stalks and may lead to higher harvest-time losses. "Corn has made a resurgent comeback following extraordinarily late planting this past spring. Dry weather through July and August, and the extremely hot weather during last half of August and first half of September speeded up crop maturity--but that did come at some expense," points out Nick Benson, corn product specialist with Latham Hi-Tech Seeds at Alexander, Iowa.~~~PAGE_BREAK_HERE~~~
"Because grain fill was speeded up," says Benson, "there was likely less starch being accumulated which means you do lose some kernel weight. However, following the late planting last spring, had you told farmers that this is the stage their corn would be at now, heading into the end of September, I don't think many would have believed you."
Hopefully, the first killing frost this fall will hold off for a while longer
With the days becoming visibly shorter, it's evident that first frost is just around the corner. After spending the entire growing season playing catch up, some growers will have to play hurry up for harvest, especially with late developing corn. Your first move should be to make a pre-harvest checklist to ensure you're ready when your corn is, says Benson. "We can't always choose when harvest begins, but we can determine our preparedness. I encourage growers to add these three items to their checklist, especially in years where time is a factor."
1) Develop and follow a plan. A good plan will outline in order of importance the fields you should harvest first. Focus on fields that show potential for stalk rot and subsequent stalk lodging.
Secondary concerns include hybrid maturity, crop residue management and logistics.
Fields stressed by weather extremes will warrant special harvest considerations. Closely watch fields that show nitrogen deficiencies, because potential for stalk rot increases when nitrogen leaches. Don't forget, plants need enough nitrogen to fill kernels and maintain plant health.
2) Get out into your fields, take a look. Get out into your fields, assess crop progress and identify potential problem areas. Note the severity and prioritize fields for harvest—be aware of crop progress and insect and disease pressure. This is the best way to ensure maximum yield. If challenges arise, you may have to harvest early. Using a strategy of "harvesting the worst first" can really pay off in the fall if you're scouting and prioritizing properly.~~~PAGE_BREAK_HERE~~~
Evaluate about 100 plants per field. Benson recommends testing 20 plants from five different locations within a field to determine standability. This helps prioritize fields for harvest. Check stalk strength by pinching the lower internodes on the plant and feel for weakness. Or try pushing the stalk to a 45-degree angle; if it breaks, stalk quality has been reduced. If more than 10% to 15% of stalks tested show poor stalk quality, or lodge at the root, consider the field for early harvest.
3) Inspect the roots of corn plants. Check the roots on some of the plants in your fields. The root mass can affect a plant's ability to stand up against late-season winds. Late-season heat may also affect the ear shank. If the shank gets weak from heat, it usually kinks or has a sharp bend. Roots can be more of an issue than stalks following a wet spring like Iowa had in 2013. Saturated soils limit growth of root hairs and brace roots, making total root mass much smaller. If these plants grow close to full size, a lot of stress will be put on the plants later in the year. Affected plants may not have the ability to take up the nutrients needed, and plants may lodge if there's a late-season windstorm and rain event.
A high-yielding corn hybrid can cannibalize itself to maximize yield. To check for these issues, walk into a field and shake the plants. Watch to see if ears fall.
4) You've prepared your equipment—now make a last-minute check. Check machinery and do necessary maintenance prior to harvest. "In years past, I've witnessed growers who, due to conditions like stalk rot, should have been harvesting a week earlier than they did," says Benson. "They simply weren't prepared for an early harvest, and as a result, lost thousands of dollars in crops that could have been saved. It is essential to have combines and other equipment in tip-top condition. Also, don't forget the importance of clean and ready to use drying facilities."
As the old saying goes, plan for the worst and hope for the best. With so many consecutive days of excessively high temperatures during August and into September this year, the corn crop was pushed along pretty hard. "Hopefully, we won't get a killing frost until the crop is mature. With some of these fields mild temperatures will need to last well into October. Focusing on aspects of your harvesting operation you can control should help ease your mind and give you a leg up once harvest arrives," says Benson. "If weather should take a turn for the worse, at least you won't be caught off guard."