Cape Girardeau, Mo., corn producer Jerry Cox has won 21 National Corn Growers Association yield contests over the last decade or more. One piece of advice from a fellow farmer has helped him reach the summit over and over – never let your corn plants have a bad day.
Cox, who farms with his son, Matthew, shared a few tips on how he achieves bin-busting yields of 300 bushels or better, at the National Conservation Systems Southern Corn and Soybean Conference, in Tunica, Miss.
Start with a complete soil test, Cox says, including micronutrients. “When we used to grow 100-bushel corn, micros were probably not our limiting factor,” Cox said. “But when we get yields up in the 200-bushel range plus, a small amount of a micronutrient might make a big difference going up the yield ladder.”
Get a perfect stand (or as close to perfect as you can get). “Our goal is to get a picket-fence stand, with even plant spacing. You need good seed to soil contact, less than 2 percent error and good, even emergence. We want to get all those corn plants up within a 24-hour period. We don’t want plants still coming up two to three days after the majority of the plants have come up. In that case, all they do is become a weed.”
Cox uses eSet vacuum disks on a John Deere planter to get that picket-fence stand. “I’ve been using the system for seven or eight years. It really helps. It doesn’t matter about the seed size.”
Research on the eSet system by Mississippi Extension corn specialist Erick Larson, who also spoke at the conference, shows that precision planting can increase corn yield. “The planter with the eSet system yielded nine bushels per acre higher than a standard metering system. As you increased planter speed with the standard metering system, you lost 4.5 bushels per acre for each mile per hour that you increased speed. There was also loss with the eSet system, but it wasn’t as great.”
The manufacturer, Precision Planting, Inc., also produces the 2020 Seed Sense monitor which Cox uses for real-time information on the performance of his planting operation. “It tells me how each row is doing, whether I have any skips and multiples and how much down force I had on my planting units. We always want 100 percent ground contact. If you don’t, then your planting depth is not going to be the same.”
Cox uses a seed emergence aid called Amplify, “which helps the plant come out of the ground faster. It’s not a starter fertilizer. It goes on the seed and gives it extra energy.”
Cox applies 3-18-18 starter fertilizer in the furrow plus potassium thiosulfate. “According to soil tests, we apply 1 pint to 2 pints per acre of zinc. That’s because zinc is the only micronutrient that my soil tests call for. The tests do call for boron, but we can’t put boron on the seed. There is one wrong way to use boron, and that is in the seed furrow.”
At the same time, Cox applies a combination of 10-34-0 and 28-0-04S, a 32-percent nitrogen, with some ammonium thiosulfate, and zinc and boron, applied to the side of the furrow. “So I’m putting fertilizer in the furrow and 2 by 2 at the same time.”
Nitrogen, as 32-0-0-2S, is knifed in when the corn is 4-6 inches tall. “On our contest acres, sometimes we dribble on some liquid between the rows when corn is 4-5 feet high, and other times, we fly on urea at about 10 days before tassel.”
Cox’s corn is planted on 30-inch rows.
Cox says much of his yield enhancement effort often show up in increased kernel size. On a 321-bushel per acre field Cox produced in 2007, kernel size was the big contributor to yield. “Usually, it takes about 90,000 kernels to make a bushel. On this corn, we had about 52,000 kernels per bushel.”
Cox will consult plant analysis reports to make sure he’s applying inputs in optimum amounts. These reports often indicate deficiencies for Cox only in boron and zinc. Plant analysis reports can be obtained all the way up to ear initiation.
When corn is at V-3 to V-4, then again at the V-8 growth stage, Cox will make a foliar application of 3-18-18.” It’s just a little bit of fertilizer (two gallons per acre) to stimulate the plant. We’ll add boron and zinc because our plant analysis says we need it.”
He adds a surfactant, Rain-Fast, “to help spread the solution on the plant and help absorption. We add water to that because we like to do the foliar application at high pressure.”
Cox’s last foliar feed, a little before brown silk, is a nitrogen product, 26-0-0-5B. “This is a little different nitrogen product. It will not burn your corn. This is usually done as an early-morning application. I usually add a fungicide.”
Cox, who is mostly furrow irrigated, said he learned from another farmer that the key to high corn yields is to never let your corn plants have a bad day. “That’s what we try to do. Every time we have some stress, we’re losing yield.”
Other commonalities between NCGA yield contest winners were researched by Larson, who plotted irrigated winners by geography.
“The thing that jumped out to me was the cluster of growers winning the contest from the southern area of the Great Plains. The thing you’ll notice about those locations is that most of the winners are occurring right on the break line, where they are having cooler temperatures respective to what we are experiencing in the Mid-South, especially the lower Mid-South.”
Other factors are much more within the control of the corn producer, noted Larson. “With higher corn markets, we have a lot of growers who are growing corn for multiple years. The second year, yields won’t fall off as much. But in three and four years, we can start to build up a lot of cumulative pest problems that can reduce our yield potential and increase our input costs associated with controlling those problems. Crop rotation can improve corn yields by at least15 percent.”
Larson said growers should improve irrigation scheduling if possible. “We’ve had a lot more drought stress the last couple of years, and we need to look at what we can do to optimize the crop water needs.”
Larson noted that corn planted in 30-inch rows showed an 8-11 bushel increase over wide-row systems. “We didn’t see a lot of yield improvement for the twin-rows over the wide, single rows.”