Annual ryegrass has been Wenningrsquos goto cover crop to rehab wet tight soils He says he has no trouble getting a good soybean stand with his Kinze planter

Annual ryegrass has been Wenning’s go-to cover crop to rehab wet, tight soils. He says he has no trouble getting a good soybean stand with his Kinze planter.

No-till beats tight clay soils

Tile, halting tillage and cover crops helped rehab hardpan clay soils to build yield

THINK different

Many Midwest farmers who’ve tried no-till on wet, tight gumbo soils in years past have given up on it, thinking they couldn’t get yields comparable to those from tilled soils. Not Roger Wenning. He kept at it, and has been rewarded with yields that just keep getting better, and benefits that keep accumulating from a system of tile, no-till, and cover crops. Wenning’s winning formula:

  • Pattern tile to take excess water away
  • Get your pH right—about 6.5
  • Grid sample for optimum nutrient application
  • Begin using cover crop mixes
  • No-till, or strip till for a few years, then no-till

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Roger Wenning’s pathway to a system that produces higher yields and healthier soils with no more fertilizer than he used 10 years ago is more evolutionary than revolutionary. He started on the path to successfully rehabbing his degraded hardpan clay soils about 30 years ago, when he came to the conclusion that continuing to till the soil wasn’t the way he was going to farm.

“I couldn’t put a spade through that hard, tight clay,” the Decatur County, Indiana farmer says. “I’d stir and till the top 4” to 6” and plow it or rip it, but that ripped soil would seal over, and in a good year I could only get 100 bushels an acre. There was a hard pan—I’ve learned that trying to combat compaction with steel results in more compaction. It just wasn’t going to work.”

Tile first to move water

So Wenning tried no-till. “But the soil was wet and cold and no-till didn’t work well,” he says. Wenning’s next step was to buy a tile plow and begin installing more tile. The tiling done in the 1970s on his farm was done at 100-foot spacings—with the new plow he began using in the 1990s, he reduced spacings to 45 to 60 feet.

“These weren’t bottomland soils, but they were essentially the same—nasty, wet, clay soils filled with water,” he says. “The tile got the water out, and we found when that happened, no-till worked as well or better than tilling the land. But we still had the issue of the hardpan.”

Wenning began experimenting with cover crops, and used strip till for a few years. “I went to strip till because the nutrient levels in my soils were really low and I wanted banded nutrients, with phosphorus in the soil, not on top of it,” Wenning explains. “I can see that when you begin to build your soils with cover crops, in that three to five year transition period from full width tillage to no-till, there could be an advantage to using strip tillage. But once you get that soil biology cranking, there’s really no need any more to strip till. In darker, better soils with higher organic matter, I’m not sure you’d need to use strip till in the transition period.”

Rye, clover, rape covers

By 2002, Wenning was 100% no-till and 100% cover crops on all his corn and soybeans.

“Annual ryegrass has always been my go-to cover crop on these tight, wet soils for the past 20 years,” Wenning says. “I noticed early on that its roots were going down 4’ to 5’ deep, through the hardpan. I also noticed water wasn’t standing in the fields in wet spots any more. Then yields started going up.”

To get more nitrogen from the cover crop, Wenning now includes crimson clover in the mix. He has switched from radishes to rape in the past three years because rape grows through the winter. “The microbes will feed all winter,” he says. “I’ve noticed the snow will be melted off fields more quickly with no-till and cover crops, because of that microbial activity.”

He’s continued to put in more tile. “You have to have tile, even with cover crops and no-till,” Wenning says, “because once you get good infiltration with those practices, excess water has to have somewhere to go. Worms plow a lot deeper into the soil than any ripper would, and mix the soil, but they would drown without tile. You need both water and air in the soil.”

[CHARTBEAT:3]

Grow soil not farm size

“I tell people I can’t afford to build my farm operation horizontally—buying more land,” says Wenning, who farms and runs an excavating business with two of his sons, Nick and Kevin. “But we can continue to grow the operation vertically by building our soil for higher yields. We’ve eliminated hardpans, cover crop roots bring nutrients back to the surface, and the topsoil can sustain life. What used to be a wet, nasty soil with four to six inches of better looking topsoil is now good looking soil down to 16 inches. I can push a spade all the way into the soil now. ”

Last year, he says, he walked out onto a field that he began renting six years ago. The field had been tilled for years, and he remembered how the ground felt under his feet when he started farming it. “I had to call my son and tell him to come over,” Wenning says. “It felt spongy like a carpet of grass, instead of like a sidewalk.”

Wenning’s corn yields have more than doubled in the past 30 years. He acknowledges hybrids have played a big part in higher yields today, but says he’s confident his system of tile, cover crops and no-till have bumped his yields by at least 30 bushels an acre above what he’d have if he were still tilling his wet clay soils.

 
Tillage increases compaction

USDA-NRCS soil health expert Barry Fisher agrees with Indiana farmer Roger Wenning regarding his thoughts on farming tight, wet soils. “If you have a wet field with a tillage pan, tilling it with something like a field cultivator to dry it out will further compact it, perpetuating the tillage pan. Tillage begets tillage,” Fisher says.

He also believes cover crops will expand porosity to help water move laterally through low spots in a field, aiding tile drainage.

“We have sticky blue clay here in our area of Indiana. A lot of people have thought they had to plow it, but cover crops are changing that thinking,” Fisher says. “With cover crops and strip till, three fourths of the surface area has soil biology. So some people are finding they can use strip till with cover crops in a transition period to no-till on tight bottomland soils, then go back to no-till when their soils are more resilient, with soil aggregates built up for better structure and porosity.”

 
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