Allen Dornacker had a major white mold problem in his no-till soybean fields 10 years ago. 

A trusted advisor gave the West Bend, Wis., farmer and dairyman some advice — “If you start composting your bedded packs and feeding the plants with plant-available nutrients, you’ll kill the spores. It will reduce your pathogen load, and in 5 years you won’t have a white mold problem anymore.”

Dornacker, who grows corn, soybeans, alfalfa and wheat across 1,000 acres, listened to his friend. He started spreading a compost mix that includes manure from his 400 cows and GYPSOIL — a calcium sulfate soil amendment — with his Meyer 9524 24-foot manure spreader.  

“I’ve pretty much eliminated white mold since I started doing this,” Dornacker says. “We used to have the worst white mold in our neighborhood. Now, I haven’t seen it in 5 years. And I use no fungicides.” 

Drywall Dropoff

Seeking a less expensive option for calcium and sulfur in his compost mix, Dornacker went to an unlikely source — drywalling companies.

“They have cutoffs and sheets that they don’t want to mess around with, and it’s all new stuff that was going to the landfill if they couldn’t find farmers to take it,” Dornacker says. “So, we started taking it and putting it with our compost.” 

The clean, unpainted drywall scraps are made of gypsum, which has the high calcium and sulfur content that Dornacker wants for his soils.

He mixes some of the drywall directly into his dairy cattle bedded packs, while incorporating the remainder into his compost piles. Dornacker has found that too much drywall in the bedded packs can make the material pasty and inhibit heating, so he prefers to blend it into the compost in moderation. 

After allowing the drywall material to weather and break down, he spreads the compost-drywall mix at about 400 pounds per acre right after harvest.

“I apply it on most of my acres, but I like to concentrate the composted mix ahead of soybeans because I’m not applying a lot of other nutrients ahead of soybeans, and I really want that sulfur out there,” Dornacker says. “We also mix in a calcite form of calcium on problem fields to get them corrected.”

Other Benefits

The elimination of white mold has allowed Dornacker to comfortably transition from 30-inch rows to 15-inch rows for soybeans, which works better with his cover crop program. 

“About 95% of our fields have cover crops, and we started harvesting a bunch of cereal rye for forage. It just seems like the 15-inch beans do a little better when you suck all that moisture out with the cereal rye.” 

On top of saving money on fungicide costs to control mold, Dornacker also cut back on fertilizer applications thanks to the drywall compost. He says the mix helped boost nutrient levels in his alfalfa fields significantly. 

“I haven’t bought potash for my alfalfa in almost 10 years,” he says. “I put about 1,500 pounds of the compost with the drywall mixed in with it every year after the fourth cutting. And on low soil-testing fields, I’ll put 5,000 gallons of liquid dairy manure on after the first or second cutting.”