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Sample soils to stay ahead of SCNSample soils to stay ahead of SCN

Soil-sampling Kansas soybean fields gives farmers a starting point for SCN management.

Jennifer M. Latzke

January 26, 2022

3 Min Read
Soybean field
SAMPLE YOUR SOIL: The first step in fighting the yield-robbing soybean cyst nematode is to sample your soil to see if you have the pest, and how big an SCN population you have, says Jeremiah Mullock, BASF Agricultural Solutions product manager, seed treatment. That helps you decide what management practices to use. Jennifer M. Latzke

Soybean cyst nematodes are sneaky yield thieves. They enter your soybean plants at the roots, underground, feeding off your plant, and robbing nutrients and water as it grows. They don’t announce their presence aboveground with visible plant damage that you can scout for in the growing season. And once they’ve established themselves in your soil, they aren’t budging.

The first step in fighting the SCN thief is to sample your soil. But many farmers still aren’t being proactive in gathering soil samples to know for sure if they have SCN, and how big the SCN population might be. That’s why in October, BASF teamed up with the SCN Coalition to create SCN Action Month, to give away free soil test kits to growers, and cover up to $20 of the costs of the lab test.

From those samples, 70% showed a rise in damaging levels of SCN, says Jeremiah Mullock, BASF Agricultural Solutions product manager, seed treatment. “And average egg counts in the damaging level of around 2,000 eggs per 100 cc [cubic centimeters] of soil,” he adds. “This really illustrates that the SCN is out there, and we need to take action in building the plant to go into the next season. Pulling that soil sample really gives the litmus test of where to start your activities for the 2022 crop year.”

Kansas State University reports that as soybean acres expand across the western half of the state, so, too, does SCN. As of January 2020, SCN was reported in 59 counties that produce more than 85% of the state’s soybeans, according to the Oct. 2 Agronomy eUpdate. The farthest west was Finney County.

Fight back

Once SCN is in a field, farmers have had two options to fight back.

First, there are resistant soybean varieties, which include the PI 88788 SCN gene for resistance. The challenge is that this same source of resistance is used in about 95% of all SCN-resistant varieties, and the SCN populations are adapting to it, according to the SCN Coalition. Relying simply on planting resistant soybeans without soil testing to see if your SCN population is changing in the field is not good stewardship.

Second, using a seed treatment with a nematicide can add another layer of defense for your soybean crop. Mullock says BASF has a seed treatment nematicide, Ilevo, that kills SCN across all stages of its development. That prevents those nematodes from developing into adults and limits their reproduction.

While we can’t fully eliminate all SCN from a field, it’s about managing the population to a low level so that they don’t steal so much yield from the soybean plant, Mullock explains.

“If you grow corn for 10 years, there’s research that shows that if you go back to soybeans in the 10th year, that SCN is still going to be there and will still reproduce on soybean,” he says.

Other SCN management tips include:

• Soil-sample. It can’t be emphasized enough, but regularly soil-sampling fields keeps you on top of your SCN population numbers and gives you a starting point from which to make the rest of your management decisions.

• Clean equipment. SCN moves with soil, so it’s a good practice to clean any newly purchased used equipment thoroughly before introducing it into your field. And clean your equipment between fields to slow the spread.

• Rotate crops. Growing a nonhost crop like corn, wheat or other small grains between soybean crops can help you deprive the SCN population of their food source, and thus reduce the population before the next soybean crop.  

• Manage weeds. Some weed species can be a host for SCN.

BASF, the SCN Coalition, and Kansas State University Department of Agronomy contributed to this article.

About the Author(s)

Jennifer M. Latzke

Editor, Kansas Farmer

Through all her travels, Jennifer M. Latzke knows that there is no place like Kansas.

Jennifer grew up on her family’s multigenerational registered Angus seedstock ranch and diversified farm just north of Woodbine, Kan., about 30 minutes south of Junction City on the edge of the Kansas Flint Hills. Rock Springs Ranch State 4-H Center was in her family’s backyard.

While at Kansas State University, Jennifer was a member of the Sigma Kappa Sorority and a national officer for the Agricultural Communicators of Tomorrow. She graduated in May 2000 with a bachelor’s degree in agricultural communications and a minor in animal science. In August 2000 Jennifer started her 20-year agricultural writing career in Dodge City, Kan., on the far southwest corner of the state.

She’s traveled across the U.S. writing on wheat, sorghum, corn, cotton, dairy and beef stories as well as breaking news and policy at the local, state and national levels. Latzke has traveled across Mexico and South America with the U.S. Wheat Associates and toured Vietnam as a member of KARL Class X. She’s traveled to Argentina as one of 10 IFAJ-Alltech Young Leaders in Agricultural Journalism. And she was part of a delegation of AAEA: The Ag Communicators Network members invited to Cuba.

Jennifer’s an award-winning writer, columnist, and podcaster, recognized by the Kansas Professional Communicators, Kansas Press Association, the National Federation of Presswomen, Livestock Publications Council, and AAEA. In 2019, Jennifer reached the pinnacle of achievements, earning the title of “Writer of Merit” from AAEA.

Trips and accolades are lovely, but Jennifer says she is happiest on the road talking to farmers and ranchers and gathering stories and photos to share with readers.

“It’s an honor and a great responsibility to be able to tell someone’s story and bring them recognition for their work on the land,” Jennifer says. “But my role is also evolving to help our more urban neighbors understand the issues our Kansas farmers face in bringing the food and fiber to their store shelves.”

She spends her time gardening, crafting, watching K-State football, and cheering on her nephews and niece in their 4-H projects. She can be found on Twitter at @Latzke.

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