Do cover crops have any downfalls?

According to farmers and experts, cover crops come with a plethora of benefits such as increasing nutrients, suppressing some weeds, and reducing erosion and soil compaction. However, according to a long-time cover crop grower, tillage is occasionally necessary unless you want slugs.

Michael Daniels, Extension water quality and nutrient management specialist for the University of Arkansas System Division of Agriculture, and Mike Taylor, a farmer and participant in the Arkansas Discovery Farms program, discussed no-till and cover crops at the National Conservation Systems Cotton and Rice Conference in Memphis, Tenn.

Discovery Farms

Daniels co-leads Arkansas Discovery Farms, farms where they examine water and soil conservation practices to show data for farmers seeking more sustainable practices.

"It's not an experiment station," Daniels said. "We study water and soil relationships in real-world situations and document what we find to measure a farmer's progress over five to seven years. We started with four farms, and we now have 12. We want to evaluate conservation practices and help develop solutions, and farmers are going to give us the best solutions because they know their ground and capabilities."

Related:Soil compaction: Cover crops, conservation tillage, and irrigation

Cover crops for 15 years

Taylor discussed the ups and downs of farming cover crops over the last 15 years and how it has changed his soil health.

"The earthworms are the key to everything," said Taylor, an advocate for no-till and cover crops. "If you have earthworms, you have healthy soil.

"No matter what we tried on our farm, we never got water infiltration as we did with a cover crop keeping roots in the ground. You plant cover crops early when you still have warm soils in the fall. Otherwise, you must plant them later in the spring, which can be a little risky if you want to plant your crop early. Planting a cover crop will provide something on top of the soil to provide nutrients as well as improve root infiltration for the coming crop."

Two-thirds of soil's organic matter comes during the wintertime, Taylor said.

"If you decide to plant a cover crop, it's important to understand that you're going to make the change, and you do it as soon as possible after harvest," he said. "The idea is that the cover crop acts as armor on the ground. It's going to help protect the ground from factors like pelting rain and erosion."

At some point, the healthy soil from the cover crop can start developing problems such as slugs.

"Slugs almost became a deal-breaker for us, so we do till some to help with that problem," Taylor said. "The benefits we've received with cover crops, such as weed suppression, healthier soil, and helping with erosion problems, outweigh the negative for us."

Related:Soil compaction: Soil health, cover crops, and compaction testing

Runoff and preserving water

On Taylor's farm, as a part of Arkansas Discovery Farms, researchers monitored runoff water, particularly concerning poultry litter. Daniels couldn't disclose Taylor's farm data at the time, but Daniels discussed some information from work done at another Discovery Farm, involving nutrient and sediment runoff as well as cover crops.

"Steve Stevens, one of our Discovery Farm participants, farms cotton and corn," Daniels said. "On Stevens' farm, we looked at the benefit of conservation tillage on nutrient and sediment runoff. Groundwater is issue in parts of Arkansas. We are depleting groundwater at a rate we cannot sustain."

To be more efficient in agriculture, according to Daniels, you can do things at the farm level such as putting in reservoirs or switching to a new irrigation system.

"On Stevens' farm, we looked at the data on nitrogen runoff, which showed a pretty good relationship," he said. "If your amount of runoff increases, the number of nutrients lost increases, so the better we can control runoff, the better we can control nutrients staying in the field. If we can reduce runoff over a long time, we can increase or maintain soil health."

Stevens is also using cover crops.

"What we see with cover crops continuously is that it keeps the hard pan broken up and helps it not to form back," Daniels said. "We've seen soil moisture sensors respond at 18 inches at Stevens' farm for the first time in the last two or three years after about four years of cover crops. It doesn't happen right away, but we're seeing a response at 18 inches to irrigation where before we only saw it at 6 inches. It didn't matter how much rain you got or how long you left the pumps on, you were only going to see the moisture sensors respond to 6 inches. Now, we're seeing a response to 18 inches because the roots can pick up the excess water, thanks to cover crops."