When Charlie Roberts returned to the Halls, Tenn.-based family farm after a short stint working in golf turf management at a high-end golf course in Birmingham, Ala., he faced a long trend of plateaued corn and soybean yields. Armed with an agronomy degree from Mississippi State University, he understood the value of soil health and started researching cover crops.
Roberts is a fourth-generation farmer who launched out on his own for the first time this year, but had a few years working with his father to prepare him for the solo flight. “To improve our yields, I thought about investing in pivots, but from my perspective, that was just putting a Band-Aid on the real problem — poor soil health,” says Roberts. “I’m one of those people who just go all in, so I made a deep dive and started learning exactly what nutrients each available cover crop delivered. Then I developed a plan.”
On a farm he and his wife Bettye Jane purchased, he started with 50 acres and drilled tillage radishes, annual ryegrass, and crimson clover at 25 pounds per acre. The difference in the soil one year later was obvious, and Roberts knew he was on to something. “The crops were healthier and more vigorous. It was simply amazing to witness,” says Roberts.
That was the first time in nearly 20 years that land on the family’s farm had a winter cover crop on it. Roberts remembers asking his father what fertilizer practices were used 70 years ago on the farm and his response included barn lot manure and cover crops of vetch, lupins, or clover. “Granddad would then take breaking plows and turn those cover crops under to get the nitrogen they released to feed his cotton,” says Roberts. “I soon began attending a few conferences. I read a lot and talked to cover crop specialists around the country to absorb all I could.”
Seed mixes, new tool, success
He found a seed supplier who could provide the seed mixes he wanted. Some of his efforts were epic failures, but some delivered the results that made him push on. “Our yields started climbing. We expanded the cover crops to more acreage and by 2015, my dad started also seeing the benefits,” says Roberts. “After he started seeing the success from the cover crops, he told me he wanted every acre on this farm cover-cropped. I’ll never forget that day.”
Today, Roberts has eight to 12 core species of cover crops he uses almost like prescriptions to match the specific row crop under production and the yield history of the farms where he has them planted. “Each one scavenges a certain type of nutrient. My winter covers include oats, triticale, radishes, and hairy vetch. For the summer, I’ll plant sunflowers, buckwheat, and sorghum-sundangrass,” says Roberts. “Sorghum-sundangrass grows really tall and did a great job of building organic matter in our nutrient-starved soils.”
Soybean and corn yields began improving, and Roberts Farms started using less fertilizer. Weed control improved, and yields started stabilizing. “That was the big thing — yield stability. The peaks and valleys of our yields started getting so much closer together,” says Roberts. “Before we were cutting 60-bushel soybeans on one field, and then coming back the next year, we might cut 45 bushels on that same field,” says Roberts. “Today, that same field may yield 50 or more bushels every year. Our better fields saw little improvement, but our low-yielding ones improved dramatically.”
In 2018, Roberts began using a roller-crimper to terminate his cover crops because some of them grow as high as 3 to 4 feet. “After we knock it down, it’s just a flat living mulch that looks like your grandmother’s thick quilt,” says Roberts. “We plant right into that matt.”
The first time Roberts “planted green” was by accident. He put out a burndown two weeks before he wanted to plant corn, but rains prevented him from getting into the field.
“By the time we could plant, the cover crop had grown a foot and I thought there was no way we can plant into that,” says Roberts. “It was only 10 acres, so we gave it a try. I remember seeing my dad standing on the turnrow just shaking his head in disbelief.”
After verifying good seed-to-soil contact 2 inches deep, Roberts dropped the hammer and planted the entire 10 acres. His neighbors thought he was a little crazy, but when the corn started tasseling, everyone could see the distinct difference down a straight line where the cover crop had been terminated and where it was still alive. “The difference in plant color and height was remarkable,” says Roberts. “I’ve been planting corn green for three years, and we started planting soybeans green last year.”
A thermometer stays in his truck because Roberts plants by soil temperature (55 degrees), not by calendar date. When he terminated one field on April 25 this year, the cover crop was in full bloom with every color under the rainbow and bees were everywhere.
“We crimped it down and planted right into the mat and sprayed 28 percent nitrogen with Gramoxone,” says Roberts. “The 28 percent nitrogen mitigates any tie up due to cover crop decomposition while the corn is emerging. For every ton of bio-mass in the field, I include 10 units of nitrogen so when that corn emerges, it’s off to the races.”
Trial, error and learning
Soybeans and corn are split 60/40 this year on Roberts Farms. A third of his bottom ground acreage under water he claimed as prevented planting with FSA and his crop insurance. If the water recedes, he may plant a shadow crop that could benefit his bottom line, too.
Roberts is not afraid to try new things. He abides by the principle: If you’re not failing, you’re not trying hard enough. “Bringing the roller crimper on the farm helped me managed all my bio-mass, and even though planting into it wasn’t pretty, it really helped hold back weeds,” says Roberts. “There are certain species of cover crops that prevent other seeds from germinating because of the exudates they release when they decompose. I’m trying to get the right combination of cover crops so we when we crush them, the saps from the cover crops will stay on top of the ground and prevent weeds from being a problem.”
Last year, Roberts planted cover crops as “trap crops” to attract beneficial insects and hopefully lower pest pressure naturally. “I planted trap crops to attract specific beneficial insects that will provide control of, for example, aphids or plant bugs,” says Roberts. “The ones I planted this year didn’t have time to work because of the late planting window we had, but I’ll try it again next year.”
Choosing varieties is easy for Roberts, but he will spend hours on his computer trying to decide which cover crops to plant, and at what rates and blends. He started planting early-maturing corn and soybean hybrids to allow the legumes and cover crops to mature in the spring for maximum nitrogen fixation. “I planted one field this year, looked back at the planter and cover crop bio-mass was just hanging all off the planter. It looked like the Hanging Gardens of Babylon,” says Roberts.
Taking a dive into cover crops paid off but was a true leap of faith for Roberts. Looking back, so was giving up his job as a golfing professional and returning to the family farm.