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Bagging bushels in the Bootheel
Widespread drought devastated many cornfields across the Corn Belt in 2012. “This year's drought was far worse than 1988,” says Jerry Cox, who farms with his son, Matthew, near Delta, Missouri. “In 1988, even our nonirrigated corn made a crop. Lots of our dryland didn't make any corn this year.”
Irrigated corn fared better, though. “We started around May 5, normally a month earlier than we usually start,” he says.
This boosted input costs. Still, it helped make a significant yield difference for irrigators in the southeast corner of the Show-Me State that's also known as the Missouri Bootheel.
“I don't think yields on irrigated corn suffered as much as they did in 2010 and 2011,” says Joe Henggeler, University of Missouri (MU) Extension irrigation specialist. “Both were hot years. But what hurt more in those years than anything were the hot summer nights. Although we had five to six days of 100°F. weather strung together this year, we didn't suffer as much yield loss. A lot of it went back to nighttime temperatures, which weren't as high as in 2010 and 2011.”
University of Illinois research notes that high nighttime temperatures in the 70°F.-to-80°F. range waste plant respiration and slice plant sugars produced by daytime photosynthesis. Thus, less sugar is available to fill kernels or seeds. This cuts yields.
Weather is an uncontrollable factor. Still, there are other steps Cox and his son use to be regular winners in the National Corn Growers Association contest. Since 1995, the father and son have been winners and runners-up in the contest's various divisions 21 times. Better irrigation management and other agronomic practices have boosted Bootheel corn production.
“When I came here in 1997, we looked at irrigated corn yields in Missouri,” says Henggeler. “At the time, we were only making 180-bushel-per-acre yields.”
This paled compared to frequently occurring 200-bushel-per-acre dryland yields in Iowa and Illinois. “So, we set goals to shoot irrigated yields up to around the 200-bushel-per-acre goal,” he says.
Following are five steps Cox and others have used to boost corn yields.
1. Select the right seed
Cox chooses hybrids based on on-farm tests that include Impact plots, a testing program used by DuPont Pioneer. He plants the bulk of his corn acres to fast-growing racehorse hybrids.
“It's all about yield,” he notes.
He says each hybrid has drawbacks, however. “A good standing hybrid might not always be the best yielding hybrid,” says Cox. “You always sacrifice something for yield.”
So it's always important to recognize any hybrid shortcomings in advance. For example, he targets high-yielding hybrids with standability concerns for harvest first.
2. Plant on time
Cox started planting corn this year on March 29. He planted all but 220 acres before April rains dashed planting plans. “The early-planted corn pollinated under almost ideal conditions,” he says.
The remainder was a different story. “It pollinated two weeks later than the rest and hit really hot weather with several 100°F. days,” says Cox.
Normally, corn planting can proceed safely with minimal spring frost worries as early as mid-March, says Henggeler. Planting corn from mid- to late March enables farmers to plant hybrids with long relative maturities ranging from 118 to 121 days. The Missouri Bootheel is far enough south that fall frost is not a major concern, he says.
Long-maturing hybrids have more time to garner sunlight. This boosts photosynthesis and ultimately yield, says Cox.
“Sunlight is what makes grain,” he adds.
3. Furrow Irrigate
Furrow irrigation releases water down furrows between corn rows from the field's top to the bottom via gravity. Furrow irrigation particularly shines for corn in drought years.
“In scorcher years, furrow-irrigated corn will outyield pivot corn by about 15 bushels per acre,” says Henggeler. Corn yields between the two irrigation types are similar in normal years, he adds.
Besides nixing evaporation, furrow irrigation also aids surface drainage by draining off excess water. Furrow-irrigated fields are also laser-leveled every few years.
“That can boost yields another 5 to 7 bushels per acre more by increasing surface drainage,” says Henggeler.
Furrow irrigation is labor-intensive, since irrigators typically have to move pipe around fields. Plus, its fixed costs of $95 per acre rival those of center pivots.
One practice that's helping slice labor is polyethylene pipe that substitutes for aluminum irrigation pipe. Irrigators punch holes in the polyethylene pipe so water can travel down every other furrow. Due to the high water flow rate of the area – often 3,000 gallons per acre – water can rapidly flow down furrows via the polyethylene pipe at the field's end.
4. Irrigate Ahead
In late spring 2011, Henggeler noticed dying corn plants in fields early in the season.
“At first, I thought it was herbicide damage,” he says. “Then I realized it was just so wet early that these plants had shallow roots and the later dry weather just shut them off. What killed these plants was lack of rooting early on.”
That's why turning the pivots early in 2012 aided Cox and other irrigators.
“We are irrigating sooner and continuing longer,” says Henggeler. “Drought can slip up on you, especially in a wet spring. All of a sudden, you see corn leaves start to curl. Roots can be shallow from not having to root down deeply.”
5. Control Weeds Early
Cox is a stickler for killing weeds early. “Don't wait,” he says. “If weeds get over 2 to 3 inches tall, you can forget about it.”
When waterhemp reaches this height, he sprays that day. That's because this prolific pigweed can grow an inch daily.
He gets his corn off to a good start with a preemergence residual herbicide like Cinch ATZ. If necessary, he follows up with a postemergence nonselective mix of either glyphosate or Liberty.
One drawback with preemergence residual herbicides in 2012 was lack of rainfall to activate them. In Cox's case, though, irrigation water accomplished this task.
“This year, producers got sour on preemergence herbicides, but we have to stay with them,” says Kevin Bradley, MU Extension weed specialist. “Year-in and year-out, preemergence herbicides will give you better control.”