Never-Till Nirvana

By John Buckner
Progressive Farmer Contributing Editor

When it comes to tillage, Dan DeSutter doesn't just mean no, he means never.

The Attica, Ind., grain farmer views any disturbance of the soil as an inherently destructive process. After 20 years of no-tilling corn and soybeans, he and other farmers are well on their way to what they call "never-till" -- a zero-tillage system that revs up their soil biology for optimum soil nutrient recycling to increase grain crop yields.

DeSutter started no-tilling to lower production costs and to protect his soil. He didn't realize he was also changing the soil biology and building soil organic matter by two percentage points. He is now firmly focused on learning how his farming system affects the unseen life below the soil surface.

POWER UP MICROBES

"The second you stop tilling, the sooner your soil [microbiology] starts trying to build organic matter," explains Barry Fisher, Natural Resources Conservation Service (NRCS) state soil health specialist for Indiana. Biological activity resides in the topsoil. It serves as the engine for the carbon and nitrogen recycling that provides food for soil microbes and makes nutrients available for growing crops.

"Once you break up the old plant root channels and earthworm burrows with tillage, you have to start over," he adds. "I've watched many farmers trying to make no-till work with tillage, and this [understanding] is what they're missing."

Fisher said if you're tilling the top 2 inches of your soil, you're injecting oxygen and burning off the organic matter from soil microbe activity. "Organic matter is the very thing you need to make your soil transition to better soil health."

It's going through the transition stage that prevents many from attaining true no-till farming, much less never-till. He adds that just stopping tillage doesn't guarantee improvements in soil health. Easing the transition depends on incorporating cultural practices, such as improving drainage, adding diversity into a typical corn/soybean rotation by including cover crops and managing a fertilizer program that complements soil microbe activity.

Experienced no-tillers recommend identifying and eliminating field problems before changing to a no-till cropping system. Roger Wenning, Greensburg, Ind., was faced with ground that was cold and hard because of the clay composition of the soil. He'd been no-tilling soybeans but quit the practice in corn because of drainage issues. Tile turned the situation around.

IMPROVE SOIL STRUCTURE

With drainage problems solved, it was time to conquer compaction. Wenning tried rippers but found long-term results less than satisfying. "That's where the cover crops come in," he said. "Wheat helped, but it wasn't the answer, so I got hold of some [annual] ryegrass and started experimenting with that."

Visible soil structure improvements have led him to keep a cover crop on every acre during the last nine years. While annual ryegrass and crimson clover are his favorites, Wenning has tried oilseed radishes. Still, it's root-heavy ryegrass that he counts on to build soil organic matter quickly.

Some of Wenning's fields had 1% to 1.5% soil organic matter nine years ago. A continuous no-till and cover crop treatment has raised soil organic matter to 2.3%.

His cover crop investment is $34 per acre for seed and aerial application.

ROOT OF THE MATTER

"Roots create the organic matter in the soil -- not surface residue or manure," DeSutter maintains. He said two-thirds of the sun's energy goes to waste if fields aren't growing something between cash crops.

DeSutter spreads both swine and chicken manure to push microbe and plant nutrient recycling on all of his 4,500 acres. "There is something that manure does for my soil biology that I don't get from commercial fertilizers," he explains. "It's impact on producing soil organic matter is relatively minor, but it's a complete nutrient package. You get your NPK [Nitrogen, Phosphorous and Potassium], some sulfur, calcium and a whole host of micronutrients."

Dan Forgey, 44-year agronomy manager for Cronin Farms, near Gettysburg, S.D., is a big believer in crop rotation. No-tilling complex rotations for 19 years and cover-cropping for nine years have moved his soil organic matter needle from 2.8% to 4%. "We can hold 8 inches of water in the top 4-feet soil profile," Forgey said. This region of the country receives only 18 inches of annual rainfall.

About 20% of his 9,000 acres of wheat, corn, pulse crops and sunflowers gets the cover crop treatment. He holds costs down to around $20 per acre by planting dwarf essex rapeseed (a short-season Brassica species). "It's twice as many seeds per pound and half the cost of radishes," he added. He believes agronomic problems, such as weed control and compaction, can be managed with rotations instead of tillage.

RESIDUE RULES

Forgey said an even distribution of residue from the combine at harvest is critical to planting in a uniform seedbed next spring. Chopping crop residue during harvest releases nutrients along with his winter-killed cover crops to serve as soil microbe food and erosion protection from spring rains. Standing residue catches winter snow for much-needed moisture.

"When we first started, we were always fighting heavy residue [at planting]," he said. "Now, our soils are active enough that we don't have enough residue. I'd like to slow the breakdown -- I don't want to speed it up."

THE WEAK LINK

Since corn is planted earlier than soybeans, it can be the perfect foil to achieving never-till success. Depending on the weather and the field, it can be enticing to make a vertical-tillage pass to reduce the risk of planting in a cold and wet seedling environment. USDA estimates indicate between 24% and 30% of all corn acres are no-tilled nationally.

Recent research from Ohio State University Extension finds only 10% to 20% of corn acres are no-tilled in that state because of yield drags of 5% to 10% as a result of nitrogen penalties from soil microbe needs during the transition stage. NRCS's Fisher believes this can be remedied.

"As you stop tillage and add crops to the rotation, you're changing the soil microbe carbon/nitrogen availability and ratio, so you may have to deliver N at different times, places and rates," Fisher said. For many successful no-till corn growers, that means adding pop-up and starter fertilizers near the roots to ensure N and P are available to get young corn seedlings off to a fast and consistent start.

That's why Indiana's Wenning bands his DAP fertilizer 2 inches to the side and 4 inches deep in his 30-inch center twin-row corn. Urea and sulfur are also banded, and he places a starter fertilizer in the row to the rate of 2 gallons of UAN 28%, 2 gallons of 10-34-0 and 1 quart of zinc.

Wenning didn't know much about soil microbes or carbon/nitrogen cycles until he started including cover crops into his no-till system. "Once you start seeing the benefits, you start to wonder where those benefits are coming from," he said.

(AG)

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