The right soil tests, inputs, equipment and even water help an Iowa no-tiller hit yield potentials.
Success is bound to come when even the performance of water is held to a higher standard as it is on Keith Schlapkohl’s Stockton, Iowa, farm.
A Kick-Start: Keith Schlapkohl’s 8-19-3 starter gets plants off to a booming start. The plant on left received no starter and has significantly less root structure.
After years of experimenting with equipment, soil tests, inputs and other areas, Schlapkohl has found a “U-Trough approach” that has him on track for reaching a 300-bushel-per-acre corn average. He consistently yields in the mid 200-bushels and his yield monitor jumps to over 300 bushels on his best-yielding acres.
“There are no magic bullets. That’s why I use a systems approach,” Schlapkohl says. “Take out any one of these steps and I can’t guarantee results.”
Schlapkohl views the planter as a precision nutrient-placement tool.
“You can do all you want with RTK or strip-till, but when you do strip-till, the nutrients are 6 to 8 inches under the seed,” he says. “I want the seed to get nutrients the day we start.”
Schlapkohl achieves this by creating an in-furrow package for the seed. It includes 26 ounces per acre of Micro-Pack, which contains live bacteria and enzymes. He also uses food-grade phosphoric acid starter (8-19-3), rather than spent phosphoric acid, which can contain lead. The starter is diluted with reverse-osmosis water to a rate of 2.5 gallons starter with 2.5 gallons water.
“Reverse-osmosis water is pure and increases the potency of the fertilizer,” Schlapkohl explains. “One grower I know gained 15 bushels per acre when he went from 5 gallons of starter to 5 gallons of starter plus 5 gallons of reverse-osmosis water.”
His planter is set up to band additional fertility on either side of the row. One side applies 32% liquid nitrogen at 15 gallons per acre, along with 5 gallons of calcium nitrate and 5 gallons of reverse-osmosis water. The other side puts down 150 pounds of dry 17-9-7-6S-6Ca per acre.
The 17 is ammonium nitrate and ammonium sulfate; the nine is soft rock phosphate and phosphoric acid; the 7 is potassium sulfate, and the 6 sulfur and 6 calcium come from gypsum and lime. The total package equates to about 50 to 60 pounds of nitrogen applied with the planter.
Soybeans also get 26 ounces of Micro-Pack at planting time, along with 2 quarts of the high-grade 8-19-3 starter per acre with 4.5 gallons of reverse-osmosis water. On the side they also get 75 pounds of the dry fertilizer per acre, 3 gallons of calcium nitrate, and 7 gallons of reverse-osmosis water.
Focus on Foliar
“I start early with my foliar program using a banding sprayer,” Schlapkohl says.
The first foliar pass includes 24 ounces of Foliar Stimulate per acre, mixed with another 2 quarts of the 8-19-3 starter. Foliar Stimulate contains organic carbons and natural plant-growth regulators, and the food-grade starter contains no salts — which means no leaf burn.
"Reverse-osmosis water is pure and increases the potency of the fertilizer..."
The second pass is a combination foliar-and-sidedress operation that goes out when corn hits about 3 feet tall.
“My Walker sprayer is set up to dribble. With the Dead-on Dribbler I put down aqua ammonia mixed with 28% liquid nitrogen and 5 ounces per acre of Safestrike,” Schlapkohl explains. “Safestrike is an organic product that has oils and citric acid in it. We’ve had good luck with it for rootworm beetle control. It either kills them or sterilizes them, which is great for corn-on-corn.”
The actual foliar is Foliar Seed Set (5-11-0-0.3Cu-0.25Mn-0.1Ca) used at 1 gallon per acre. Foliar nozzles sit below the canopy and blow the foliar application back up onto the leaves.
When dry conditions allow, he pushes applications later to impact tasseling.
“It’s pretty amazing when you can get this application close to tassel,” he says. “You put the Seed Set on and 3 days later every tassel is out. If you leave a skip, tassels in those spots won’t come out for 10 days.”
Urea-based foliars aren’t used because they carry a cyanide molecule, he explains.
“I’ve seen urea-based foliars take 30 bushels off of yield in a good year,” Schlapkohl says. “I’ve gotten a response with them in a stressful year, but I’m just not going to go there anymore.”
Schlapkohl uses an additional green silk aerial application of 1 gallon of Foliar Seed Set and 5 ounces of Safestrike per acre. This application is made when all the silks fall off of a shucked ear, meaning pollination is complete, but it’s not brown silk, yet.
“This application is made to eliminate the stress period,” Schlapkohl says. “If at any time after pollination you have heat stress, drought stress, too much rain, etc. — and if the plant is stressed and can’t get enough energy — it starts aborting kernels off the tip.”
In 2005, Schlapkohl treated stressed corn with 4 gallons of 21% liquid nitrogen, since SeedSet wasn’t available at the time. He didn’t lose any kernels off the tip of the ear, while his neighbors lost 2 to 3 inches.
“I got 235 to 255 bushels that year, while 100 bushels was the norm for my neighbors,” he says. “I got a 100-bushel yield pop because I took that corn through a stressful period and it didn’t suffer.”
The final foliar is a brown silk application of 1 gallon of Rondo (5-15-5-1Ca-0.25Mn), a companion product to Foliar Seed Set that puts the plant into the male dominant stage of growth to increase seed bulk. In 2009, Schlapkohl combined this with a fungicide because of excess disease pressure.
“In 2009, test weights around me were 47 to 51 pounds and I’ve never dropped below 55 pounds, with the average being more like 59.8,” he says. “I attribute that to Rondo. It’s a nitrate, nitrogen and potassium source that helps bulk the plant.”
His soybean foliar program consists of a 12-ounce application of Foliar Stimulate mixed with 2 quarts of 8-19-3 at the second to third trifoliate.
“The 8-19-3 can shorten the nodes on the plant and improve branching, even on varieties that don’t normally branch,” Schlapkohl says.
About 5 to 6 days after herbicide application, around summer equinox, soybeans get 2 to 4 quarts of Foliar SeedSet per acre every 10 to 18 days. The final application is 1 gallon of Rondo at pod fill.
The Right Soil Test
Schlapkohl uses the Morgan/LaMotte test instead of a CEC test to evaluate his soil.
“The CEC test uses acid to wash phosphorous and potassium out of the soil, and then measures it,” Schlapkohl explains. “Does a root have that capability? No.”
The Morgan/LaMotte test more closely mimics root exudates to wash phosphorous and potassium out of the soil, allowing for measurement of plant-available nutrients.
“The CEC test shows you what’s in the savings account, while the Morgan/LaMotte test shows what’s available to the plant to build the crop,” Schlapkohl says. “Soils testing high in phosphorous and potassium on the CEC test don’t do me any good if it can’t be used by the plant.”
"I had 900 acres that were fertilized by magic. The magic was calcium..."
— Keith Schlapkohl
The test is expensive, so Schlapkohl uses his yield monitor to guide his soil sampling. He pulls samples on the best- and worst-yielding acres.
“I’ve found in the last 5 years that the Morgan/LaMotte test tells me a lot more of what’s going on,” he says.
With his soil test, Schlapkohl hopes to achieve a 1:1 phosphorous-to-potassium ratio and 7:1 calcium-to-magnesium ratio.
“If I’ve got a spot that’s not yielding well, I usually have more potassium than phosphorus, or have a 3:1 calcium-to-magnesium ratio,” Schlapkohl says. “I’ve also found that as my soils get healthier, the Morgan/LaMotte test and the CEC test kind of come together.”
On the flip side with unhealthy soils, Schlapkohl says it’s typical for the Morgan LaMotte test to be very low, while the CEC test shows all sorts of nutrients.
“If the soil isn’t healthy and there isn’t any microbiology or oxygen, those nutrients aren’t available to the plant,” he says.
One way Schlapkohl improves soils is by balancing the ratios with applications of Power Lime (a mix of calcium sulfate and three other limes).
“In 1990, I had a 320-acre farm with a base saturation of 41 parts calcium to 41 parts magnesium. I started using Power Lime on it right away because it was the worst piece of dirt I had,” Schlapkohl says. “It’s had more Power Lime on it than any other field we have, and now if I want good yields, that’s the farm I go to. The rest of my fields are 3 to 5 years behind.”
If producers want high yields, they need to start looking at the elemental chart, he says. If they understand the chemistry, they can identify what’s wrong and fix it.
In 2000, he remembers feeling that something was holding back his crops, so he had his soils tested by soil type.
“We tested 950 acres and 930 acres needed potassium. I have not put any potassium on other than a little in my starter for the last two years, and soil tests pulled last summer only showed 35 acres that called for potassium,” Schlapkohl relates. “I had 900 acres that were fertilized by magic. The magic was calcium.”
By applying Power Lime, Schlapkohl says he was able to force potassium off of the soil molecules with the calcium — a cost-effective solution in his eyes.
“How much cheaper is calcium to buy than potassium?” he asks.
The Whole System
Inputs and tests aren’t the only things scrutinized. Schlapkohl manipulates his farm machinery to best suit his needs.
When he planted 280 acres of corn with two rows plugged, he moved his Redball monitor to just outside the cab to keep a more watchful eye on it.
He’s a long-time user of Soil Doctor, a variable-rate, nitrogen-application system. It determines rates based on soil organic matter and the CEC of the soil, changing rates up to five times per second with an electric valve.
“I prefer this technology. By the time you sense needs based on the plant’s appearance, the damage is already done,” Schlapkohl says.
He went to reverse-osmosis water over well water due to impurities.
“Herbicides react with minerals in the water and get tied up,” he says. “With reverse-osmosis water, my herbicide rates are less than half what they were, and I still see great control.”
Schlapkohl continues to investigate ways to improve his no-till system, and that quest for knowledge keeps him pushing yields higher and higher.