TRENTON, Ohio – You feed your dog or cat every day, not six months out of the year. In the same way, the microbes in the soil need to be fed 365 days a year. Kent Sonneberg and his son, Ted, operate Sun Mountain Dairy in Henry County, Ohio. They maintain year-round cover on their nearly 2,000 acres of cropland while limiting phosphorus losses on the landscape.

Kent Sonneberg will be the keynote speaker at the Regenerative Ag Field Day sponsored by the Butler, Clermont, Hamilton and Warren soil and water conservation districts on Aug. 26 in Trenton. Sonneberg will describe how they keep every acre of soil covered on their 3,000-cow dairy, where crop rotation is a thing of the past.

Sonneberg is a lifelong dairy farmer. He farmed with his father, Reinhold, for 30 years. They had 25 cows and expanded to 50. Ted, graduated from Cornell University and then worked at a big dairy farm in California. Fifteen years ago, he came back to Ohio.

They bought a larger dairy farm a few miles down the road and expanded to 700 cows, then 2,000. They’re currently at 3,100. Kent mostly takes care of the grain end of the farm while Ted takes care of the dairy.

“We’re in the Black Swamp area,” Sonneberg said. “It reverts back to a swamp every spring and fall. It is totally flat. I do 100 percent green; I plant a cover crop on everything. We try to have something growing 365 days a year. We try to work with the biological aspect of it. You need fewer inputs that way.”

Dairy farming, manure and cover crops work together to retain some of the nutrients on the farm, Sonneberg said. They also have over 40 subsurface water control structures. During the winter, those control structures limit flow to minimize runoff and store water for midsummer crops. In early spring and fall, they can allow groundwater to flow freely.

“We plant wheatlage in the fall on 900 acres and then we come back and plant a cover crop, whatever that cover crop can be within the H2Ohio guidelines,” Sonneberg explained. “You can obtain funding through that.”

Wheat is a grain crop, but they harvest it at the end of May and chop it as silage. Before the ground gets too hard, within 24 to 36 hours, they will plant corn. On another 850 acres, they kill the cover crop planted the previous fall and ideally plant corn two weeks later. In their monoculture system, that seems to work better than planting the corn into the cover crop.

“We are double-cropping on the wheatlage ground, on the other ground we’re doing a single crop,” he said. “We’re growing a monoculture because we need the corn for that many cows. Actually, we need more corn silage than we can raise, so we buy corn silage from other farmers.”

They usually put manure on the wheatlage ground in the spring. It has all the phosphorus, potash and nitrogen that they need, Sonneberg explained. Most people will use urea on wheat to get a bigger crop, but they don’t need that because the manure has the necessary nutrients.

“The manure is a good source of carbon,” Sonneberg said. “We drag-hose most of the manure in a liquid form, we drag-hose or we do a frac tank. You take it to the field in big trucks, and the hose goes out into the field and so it is easy to put that manure through a hose at 12,000 gallons of manure to the acre. That’s what we’re allowed.”

Every other year, half of the farm is soil tested. So, half the farm gets tested this year, and the other half of the farm gets tested next year. Then they review the test. They might go up or down. The main thing is to get the organic matter in the soil up because organic matter is the key to holding water in the soil.

In summary, he said: “I’m not saying our way is the best way to do things, but you have to adjust the situation to what works for you.”

Sonneberg was a 2024 Ohio Master Farmer. He is a farmer advocate for The Nature Conservancy and has served on the Henry County SWCD for many years.

The Regenerative Ag Field Day will be 8:30 a.m.-3 p.m. at 4445 Oxford-Middletown Rd., Trenton. For information, visit butlerswcd.org.