Listen to the Land - 8

Microbe Management

Seth (left) and Adam Chappell first began cover-cropping to control Palmer amaranth. (DTN/Progressive Farmer photo by Lisa Buser)

The Chappell brothers use a simple principle to guide their crop-management decisions: Healthy soil helps make a healthy farm. It starts by thinking small.

"The big key is the mycorrhizal network in the soil," said Adam Chappell, of Cotton Plant, Arkansas. "That means the soil is alive. If we have dead soil, we're never going to make it on this farm."

That microscopic network improves the crop's ability to take up both water and nutrients. Boosting the activity of the billions of microbes present in a square foot of soil takes care and planning. For Adam Chappell and his brother Seth, it required educating themselves about how those microbes work, then changing the production system to let them provide maximum benefit to the crop.

Soils in their area are not naturally highly productive, requiring innovation to improve them. Since the brothers started farming with their father in 2006, they made their biggest strides by finding ways to help soil microbes thrive.

"Most fields here are sandy loam, pretty light soil, naturally very low in organic matter," Adam explained. "It's not uncommon to see organic matter of 0.5 to 1%. On our fields, we're now running around 2%. We'd like it to be better, but we're working on it. It's a slow process, but no-till and cover crops are helping us get there," he said.

"We want those microbes to have a buffet of cover crops and something growing out there all the time," he continued. "That's why we like to have a blend of cover-crop species growing through the winter. We're not really sure exactly how those soil microbes interact, but what they do all goes together to make healthy soil. That's what we're after, to build soil so that it gets better year after year, decade after decade."


It all required a significant mental shift for the two siblings. The fourth-generation farmers in eastern Arkansas grew up on a farm with sterile soils. They may not know exactly how the soil microbes work, but they do know what destroys them: tillage and starvation.

Responding to the spread of glyphosate-resistant Palmer amaranth got them started on their road to healthier soils. "We began growing cover crops specifically to fight Palmer amaranth," Adam said. "We were spending way more than we could afford (to control the weed). Chemicals alone weren't getting it."

At about the same time, the Chappells got interested in no-till, which led to weed-control research. "I did internet research trying to understand how organic farmers control weeds. A lot of them plow, which I knew wouldn't work for us because we wanted to go no-till. It seemed that planting into a cover crop like cereal rye might be the way to do it," Adam recalled.

In spring 2010, they tried 300 acres of no-till. Then, they rolled rye the next spring prior to planting soybeans. The mat on the soil surface helped control Palmer amaranth, encouraging the Chappells to try more acres, plus it provided added benefits. They still use PPO inhibitors in conjunction with the cover crop to keep Palmer amaranth manageable.

"I could find earthworms when I'd look at the soil. It smelled alive. It was changing. We did the cover crops specifically for Palmer amaranth [control]. That worked, but a lot of good things came with the cover crops," Adam explained.

"Now, every acre gets a cover crop of some kind. We figured out that every time we tilled, we were bringing up more weed seed," he said. "So, why till? We found that a key to soil health is managing moisture, which cover crops help. This system conserves moisture and makes it easier for roots to go down to the moisture in the soil profile."


Adam said it was no quick fix but more of a season-by-season evolution.

"We've eased into this. Every time we add a new variable, we can sit back and figure out what it did," he said. "We do not eliminate the green bridge from cover crops to corn, soybeans or cotton. We're seeing that by planting green, we see less insect pressure early in the crop, because we're leaving habitat there for multiple species of insects. That's the key. I think by using an insecticide with a burndown in cover crops, you're leaving yourself open for a problem."

They spray Roundup or Gramoxone, wait 24 hours then plant the crop.

After 2010 until 2017, a tillage tool never touched some of the Chappells' fields. Then, in 2017, they tilled everything because they switched to planting flat rather than on beds. That was likely the final time for tillage on their land.

"At this point, I hope it never happens again. We've gotten tremendous benefits from no-till and cover crops," Adam said. "We've seen a drastic change in soils. Organic matter increased almost a full percentage point. Weed control is better because of the residue. Water infiltration is better, so there's less loss to evaporation."

Tweaking the cover-crop program through the years boosts soil health, as well. The Chappells now are looking at row rice planted in a mixture of black oats, cereal rye, hairy vetch, Austrian winter peas and crimson clover. Soybeans follow in that same field the next year.

"It's easy. There are no tillage passes. We used to have bad erosion problems. No more. Wind erosion is completely gone, too. Something is growing on that ground all the time. It's a better system and a lot cheaper," he said.


Cover crops vary from field to field and crop to crop. "We've evolved a lot since the days of just using cereal rye. We discovered that some crops won't grow well on our fields," Adam said. Many of their soybeans, for example, get planted into residue from cereal rye, radishes, turnips and black oats. "Radishes have a big tuber and make a big nutrient sink. That helps the soybeans after planting," he explained.

Corn goes into residue from cereal rye, vetch, crimson clover and Austrian winter peas. They're still trying different cover-crop mixes to see what works best.

"We've tried blue lupine in 2018. We've tried triticale. We've planted spelt instead of oats and rye. It has a big root mass and grows a lot, which makes it a good cover crop. We're planning to use more black oats, because it's a longer-season crop and doesn't go reproductive as early as cereal rye," he said.

The Chappells kill the cover crops using Roundup on corn ground and Gramoxone and preemergence herbicides on soybean fields, then roll before planting. "It's a cheaper program than we used to have. We don't have the burndown expense," he said.

Now, no-tilling into cover crops across 8,000 acres, Adam sees only positives from the system. "Our yields haven't gone up, but they haven't gone down, either. The big difference is, our inputs have gone way down. We rent all our ground. If our yields weren't competitive with our neighbors, we wouldn't be able to get the ground," he said.

Corn yields run 180 to 220 bushels per acre. Soybean yields are in the 40- to 60-bushel-per-acre range, and cotton, about 1,200 pounds per acre.

"We're farmers. We'd like to increase yield. We'd like to pull in 70- to 80-bushel soybeans. But, we also want to make smart decisions for the long-term," Adam said.


The Chappell brothers put tradition and the latest science to work. Adam has a bachelor's degree in botany from Arkansas State University and a master's degree in entomology from the University of Arkansas. Seth has an undergraduate agribusiness degree.

"I put a lot of value on everything we learned from our dad and grandfather. They did what was best to keep the farm together during their time. Now, things are changing, just like they've always changed. Every era is different," Adam said.

"When I finished high school and went to college, I knew I wasn't ready to farm yet. I wasn't quite ready for the real world. I liked science, so I studied that. I graduated and did independent consulting and field scouting for a while, which broadened my knowledge base. I also learned that if you just work hard and be diligent, things work out," he said.

"Now, that science background helps me on the farm. I can see ecological principles at work right here with the no-till and cover crops. It's a long-term project. We learn new things every year. It will never end."