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dfp-ronsmith-scoggins.jpg Ron Smith
Keith Scoggins, Arkansas NRCS, left, and Clay Smith, Arkansas farmer, discussed cover crop benefits in irrigated cropland at the recent Conservation Systems Cotton and Rice Conference in Memphis, Tenn.

Cover crops focus on soil health

What's your focus? High yields? Bragging rights? How to get earlier production? Why not soil health?

What's your focus? High yields? Bragging rights? How to get earlier production?

"Why not soil health?" asks Keith Scoggins, state cropland soil health specialist in Arkansas for the Natural Resource Conservation Service.

Scoggins and northeast Arkansas farmer Clay Smith discussed the role cover crops play on highly productive irrigated soils at the recent National Conservation Systems Cotton and Rice Conference in Memphis Tenn.

"Some farmers make high yields but still go out of business," Scoggins says.

"Soil health, not yield," he says, may be more important to the bottom line. Healthy soil can improve profit potential. Yield from a cover crop and no-till system may equal or exceed yields in conventional systems, but other advantages make a difference, too.

Stability is a key and Scoggins says building organic matter makes a difference.

Improved water infiltration, for instance, conserves soil moisture. "Organic matter at 1% holds 27,000 gallons of water," he says. "That means 29 days between irrigations because of organic matter residue.

"The path to healthy soils is also diversity," he adds. "Keep cover crop mixes diverse." Corn, cotton and soybeans offer no diversity to fields. Monocropping is not diverse; nature is."

Rotation helps, but the diversity producers get with cover crops makes a difference with rooting depth and rooting structure. A mix such as wheat, cereal rye, and brassicas help improve soil health for soybeans corn and rice crops.

Disturbing disturbance

Scoggins says the combination of no-till and cover crops limits soil disturbance. "We can't build organic matter with continuous tillage."

He says in the past farmers made as many as 14 passes to prepare land for planting. Few make that many trips now, but bare ground leaves little residue to improve soil health.

"Just one cover, wheat, for instance, is less disturbing," he says. "Even less disturbing is planting into a shoulder-high residue of a cover crop."

He adds that new high-speed planters perform well planting into heavy residue.

"It is important to keep something growing on the soil, to keep the soil covered so we don't lose moisture."

He says residue also lowers soil temperatures.

Old crop or cover crop residue is too valuable to waste, Scoggins says. "Burning field residue and then working up the land leaves nothing for the soil."

He says improving soil health results in reduced production costs, including less fertilizer expense. "Producers can maintain yields, reduce equipment maintenance costs, and improve irrigation efficiency with cover crops," Scoggins says.

Basic benefits

Smith counts four specific benefits from cover crops — increased water infiltration, improved soil health, decreased soil loss from erosion and reduced weed control costs.

He raises corn, soybeans, rice and wheat with his father, Terry, near Paragould, Ark. "We started with around 50 acres of cover crops," Smith says. "In 2019 and 2020 we established 1,500 acres. We plant a mix of wheat, clover and turnips going into corn and black oats and cereal rye for soybeans.

"With cover crops, we get no runoff after two years," he says. "We have cut water loss significantly."

Smith says increased moisture retention allows them to improve irrigation efficiency significantly in row crops. "We watered only three times last year on a cover crop field. We irrigated six times on conventional acreage.

"Improving soil health has improved plant nutrition, too," he adds. "With cover crops, nutrients are more available because of the cover crop roots."

Keeping something growing on the field year-round also reduces soil erosion.

"Weed control improves, too," Smith says. "We cut down on herbicide applications because the cover crop prevents weeds from emerging."

Retooling necessary

Switching from conventional tillage to no-till and cover crops means retooling, Smith says. No-till coulters and cleaners "are about mandatory. So is the RTK guidance system."

Termination is a tricky part of cover crop management. Smith sets a late February target date, so corn fields are ready to plant by late March.

Scoggins says if the soil holds plenty of moisture, he might wait until planting time to terminate. "In some cases, we spray to terminate at night and start planting the next morning. In dry fields, we might start a week to 10 days before planting."

He says planting into green cover has not been a problem and he's seen no issues with a green bridge supporting insect pest populations. "We get more beneficial insects as pest populations increase.

"If we don't have enough predators, we will apply an insecticide," Smith says. "That's why we scout. After emergence, we scout hard."

Smith and Scoggins agree that a reliable cover crop seed source is essential.

"Efficiency is our main goal," Smith says. "What we do will not work everywhere, but some of what we do will work just about anywhere."

"Don't be just sustainable," Scoggins adds. "Be successful."

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