Originally published May 1, 2017
A strip-tiller’s fertilization strategy is influenced by a combination of factors — when they build strips, soil variances and health, climate and equipment setup.
Building a bankable nutrient management strategy has been a common theme throughout the history of the National Strip-Tillage Conference with strip-tillers, agronomists and researchers offering proven methods for creating a balanced, efficient fertility program.
For Shell Rock, Iowa, strip-tiller Jeff Reints and his son, Clay, they’ve long subscribed to the philosophy that fertilizer needs to be placed where plants need it most — in the root zone.
“Why put fertilizer next to the crop?” Jeff says. “Whether you’re strip-tilling in the fall or spring, apply fertilizer where it’s going to provide the biggest benefit.”
Since adopting strip-till more than a decade ago on their 2,000-acre corn and soybean operation, the Reints have made numerous modifications to their system, including a switch from fall to spring strip-till in 2008 to improve crop flexibility and allow more time for residue to break down during winter.
In 2014, they moved from a 16-row to a 24-row Harvest International UltraMax 60 series 60-foot toolbar with Dawn Pluribus coulter-style row units with Montag’s high output dry fertilizer delivery system.
“We upgraded from our 40-foot toolbar this year to cover more acres because we typically like to strip-till 24 hours ahead of the planter, seal in that moisture and have excellent seed-to-soil contact,” Jeff says. “With a 60-foot rig, we can run about 8¼ mph, which allows us to cover about 60 acres per hour, well a head of the 5½ mph we run our 24-row Case IH planter.”
One constant for the Reints has been their commitment to banding fertilizer in the strip because it saves time, fuel and fertilizer costs.
For nearly a decade, they’ve yielded 10% above their county average for corn, and Jeff says their crop insurance agent tells them they have one of the highest actual production history (APH) numbers on farm ground that is several points below the county average. (CSR-corn suitability rating)
At the first National Strip-Tillage Conference in Cedar Rapids, Iowa, the Reints shared 2014 research, comparing broadcast application of fertilizer in a conventionally tilled cornfield with banded application in strip-tilled field.
To illustrate their comparison, — see video below — they pulled corn plants from the two different fields and mounted 8 plants on a board, 6 inches apart, to represent a 34,500 planting population. The Reints then weighed, on a gram scale, the exact amount of potassium (K), phosphorus (P) and sulfur applied for a 200-bushel-per-acre yield goal.
For the broadcast application, they applied 160 pounds per acre of diammonium phosphate (18-46-0), 100 pounds per acre of potassium chloride (0-0-60) and 100 pounds per acre of ammonium sulfate (21-0-0-24). The total application (360 pounds) costs $74 per acre.
“We measured it out to 3.75 grams of fertilizer per square foot, which meant that this is what we’d see on the soil with a broadcast application by a floater,” Jeff says.
For strip-till, the Reints reduced application rates by 25%, banding the fertilizer in an 8-inch wide by 5-inch deep strip. They applied 120 pounds of diammonium phosphate, 75 pounds of potassium chloride and 75 pounds of ammonium sulfate.
Not only was banding a cheaper method — $18 less per acre than broadcast application — the concentration of fertilizer was higher with 10.5 grams per square foot. Overall, the Reints estimate a fertilizer application savings of more than $20,000 per year with banded application in strip-till, vs. broadcast application in conventional tillage practices.
“We know we can reduce application rates with strip-till and talking with agronomist Brian Hefty, he told me that broadcast rates have to be 50% higher than banded application to achieve the same effect on crops,” Jeff says. “In our example, what the root mass is seeing with strip-till is the equivalent of broadcasting 1,010 pounds per acre of fertilizer.
“If you call up your local co-op and order 1,010 pounds per acre, you will be getting a Christmas card from them because that would be one giant order.”
Strip-till is also saving the Reints more than $4,000 per year in fuel costs because they only make one pass in spring to place fertilizer, rather than multiple field preparation trips in a conventional tillage system.
“When our combine leaves the field, we are 0.40 of a gallon of diesel from planting the next crop,” Jeff says. “We only burn about 0.40 of a gallon per acre applying one-third of our nitrogen, all of our potassium and phosphorus and building the strip, all in one pass.”
One of Persia, Iowa, farmer Bill Darrington’s guiding principles for managing his operation is to treat it like a human being. The longtime no-tiller and strip-tiller builds his fertilization strategies around the philosophy that like humans, crops need to eat on a regular basis to grow and remain healthy.
“It takes multiple feedings for us to maintain complete nutrition and stay energized,” Darrington says. “It’s the same concept with plants. We know that corn plants determine how many rows will be around an ear at V3 stage, and how long that ear will be at V8.
“It’s all about basic pre-natal care to promote a healthy and happy growing environment to maximize yield potential.”
Interested in learning more about fertility? Enjoy this complimentary eBook download, Hitting the Sweet Spot with Strip-Till Fertilization Practices.
But he adds that continuously feeding crops fertilizers with potentially harmful elements, or the equivalent of human “junk food,” can stunt plant growth and sterilize soils. The long-term practices of banding fertilizer beneath the soil surface, the use of organic-based nutrients, and multiple, timed applications throughout the growing season have contributed to strip-tilled corn yields over 290 bushels per acre on some of Darrington’s highly variable soils and sidehills.
While he typically doesn’t apply any fertilizer at planting, Darrington has developed a comprehensive fertility program to suit his operation, with an eye on environmental stewardship, organic efficiency and balanced soil health This starts with a broadcast application of 150-200 pounds per acre of ammonium sulfate (AMS) in early winter to alter the carbon-nitrogen ratio in the residue and jump-start decomposition.
The cornerstone of his split-application system is the banded placement of nutrients in spring with the strip-till rig. With the front anhydrous knife on his 18-row Blu-Jet dual-placement strip-till toolbar, Darrington injects 40 gallons per acre of 28% N and 5 gallons of ammonium thiosulfate, P and K (7-25-5), plus, zinc and sugars in the strip, about 7 inches deep.
Then a second application system of the dual-tube knife applies about 10 gallons per acre of a 2-16-14 blend from Indiana-based CarboTech America, a direct liquid fertilizer supplier.
“We drilled a small hole in the back of the second tube to shoot the product out behind the knife. This is 2 inches shallower than the 28% and keeps the tube from plugging, and gives us a staggered application site in the strip,” Darrington says. “We don’t want to apply everything all in one spot and walk away. I want that soil profile to be layered with nutrition, eliminating our corn from being pale yellow until it finally runs into the fertilizer hot spot.
“The secret to my success is placing a little at a time and allowing the root system to run into more nutrition as it grows.”
Darrington says the dual application is contributing to more consistent emergence and corn plant health throughout the growing season. But just as important as the timing of applications, is the type of fertilizer being banded in the strips.
He recalls a 1999 visit from mentor Ray Rawson, who helped change Darrington’s thinking about how non-organic elements in fertilizers can negatively impact soil health. (see sidebar – Should You Quit Using Anhydrous Ammonia?)
“Ray came to my farm and in 30 seconds could tell I was still applying anhydrous ammonia because he showed me a hardpan and crack in the soil where the anhydrous knife ran,” Darrington says. “That was the last year we ran anhydrous. Today, I have a much better understanding when banding fertilizer, it is always important to remember the good and the bad ingredients are all being banded in the root zone. This could be salt or chloride or even some heavy metals.
“The million dollar question for me is always, ‘What else is in it?’ because I’m willing to pay a little more for products that are going to promote and preserve soil biological health.”
By Laura Barrera
Bill Darrington knows his comments aren’t exactly popular, but he has no problem telling growers they need to give up anhydrous ammonia — especially if they care about soil health.
At the 2015 National Strip-Tillage Conference, the strip-tiller from Persia, Iowa, recalled the time he realized the negative impacts anhydrous was having on his soils.
Ray Rawson, known as the ‘father’ of zone tillage, had come to his farm and was examining a root pit. Darrington says Rawson took out a pocketknife and began digging. About 8 inches down, he hit a “shelf,” Darrington says. “It looks like I took a piece of plywood and wedged it into the soil profile,” he told the audience.
Rawson said to Darrington, “Well, I see you’re still running anhydrous.” In that moment, Darrington decided he’d never let anhydrous ammonia touch his farm again.
Darrington’s not the first person to call out the disadvantages of using this popular source of N. At the 2015 National No-Tillage Conference, world-renowned soil biologist Jill Clapperton explained how deadly it is to earthworms.
“If it’ll kill us, it’ll kill them,” she said.
Darrington understands the reason a lot of farmers like anhydrous — because it’s cheap. But he asks: How cheap is it if it’s killing your biology?
“That’s why they make runways out of it,” Darrington explains, referring to the dirt runways made during World War II. “It kills the biology. It knocks out the calcium. Basically sterilizes the soil. Hit it a bunch of times with a disc and rolling packer, you’ve got yourself a runway.”
With the chances of volatility harming germination, the harm it causes to soil biology, and the safety risks it poses to growers, Darrington says he doesn’t think anhydrous and strip-till fit. I think that could also extend to no-tillers.
What are your thoughts on anhydrous ammonia? Have you moved away from it because of concerns for the soil health? Let us know what you think in the comments section below.
And hear more from Bill Darrington on his nutrient management strategies to include sugar applications in his Strip-Till Farmer podcast below.