By Matt Reese
Like a kid on Christmas morning, Allen Dean can hardly wait to dig into his soil test results from the fields on his Williams County soybean and wheat farm. He excitedly looks to see how his soil nutrient holding has improved each year —something that has been happening consistently since he combined no-till and cover crops nine years ago.
“We’re applying less and less fertilizer and our soil test levels keep going up,” Dean said. “The cover crops are mineralizing a lot of nutrients and it is exciting to see that.”
Though no-till has been a standard practice on the farm for many years, the use of cover crops has been a more recent addition. Dean started looking into cover crops, including hairy vetch and oats, in the early 1980s as a way to improve his soils.
“We weren’t getting the results we wanted so we stopped planting them until we started looking at cover crops again nine years ago,” Dean said.
Since then, Dean has become a strong proponent and advocate of cover crop use in combination with no-till. He has almost all of the 1,900 acres he farms covered this winter with either wheat or some other combination of up to eight different cover crops. One field has all eight —annual rye, radishes, crimson clover, cahaba vetch, triticale, turnips, blue lupine and volunteer wheat.
“We have found that we need a brassica, a legume and a grass together in the field,” he said. “We have learned that once you get those three in the mix, it just works a lot better.”
The brassicas, such as turnips and radishes, help to loosen the soil. The legumes fix nitrogen and the grasses build soil structure, suppress weeds and reduce erosion. The thought behind the additional crops in the mix is simply to increase the diversity of the roots in the soil and the benefits of the cover crops.
“We are starting to realize the value of going from a monoculture to a polyculture,” he said. “The biggest thing with managing the cover crops is that you need a herbicide program worked out ahead of time and you have to be ready to kill the crops before they go to seed, especially with annual rye,” Dean said. “It takes more management, but once you get it figured out it is not that bad. We have had a couple of issues with annual rye. Now, in any field we are going to plant to wheat, we burn down with glyphosate and 2,4-D. Then we usually do a November application of Harmony Extra or Sencor.”
For soybeans, Dean burns down the cover crops with glyphosate, 2,4-D and Thunder Master (formerly Pursuit) seven days prior to planting. There are certainly management challenges with the cover crops, but Dean feels the benefits are well worth the effort.
The cover crops in Dean’s fields benefit water quality by bolstering microbial life within the soil, increasing organic matter, quickly breaking down wheat residue, and, in the end, boosting the bottom line.
“Ultimately this is about increased yields and profit,” he said. “In the early years, I was always excited to see what was happening on the top of the soils. Now I am more interested in what is happening underneath.”