Based on the level of pH in soil, ISU scientists discovered they can predict the types and severity of diseases found in soybeans.

Gregory Tylka, soybean nematologist, has been working on the Yield Project, the project researching diseases in soybeans, since it started in 1997.

Tylka, professor of plant pathology, said the level of pH in soil can help determine the severity of cyst nematode or brown stem rot.

Soybean cyst nematodes are microscopic worms that live in soil, fresh water or salt water, Tylka said. Cyst nematodes cause the most widespread damage throughout Iowa, he said. Brown stem rot is a disease caused by fungi in soil that also get food from soybean plants, Tylka said.

The lower the pH in soil, the greater the risk for brown stem rot to hurt soybean plants, he said.

The opposite is true for soybean cyst nematodes – the higher the pH level in soil, the greater risk for damage, he said.

While more research is slated to find out why the pH level in soil has a direct correlation with the two diseases, Tylka’s discoveries already are useful to farmers.

“Farmers can use this information to look for diseases,” he said.

Antonio Mallarino, associate professor of agronomy, is working with Tylka on the project. A goal for the Yield Project is to apply new technology to the researchers’ work with the soybean diseases, Mallarino said.

“We are trying to use new technology in a cost-effective way for farmers,” he said.

With the information from this project, farmers can use management strategies to help control soybean diseases, Tylka said. There are a variety of seeds farmers can buy that will resist a certain disease.

“These seeds suppress activity, not completely stop it,” he said.

Most of the seeds are only resistant to one disease, Tylka said, which makes this project very helpful to farmers. They can tell what disease is most common in their yield and buy seeds that will reduce the risk for that disease, he said.

“Everyone wins,” Tylka said. “The farmers pay us, but we generate information about their soybean diseases so they can try to reduce the risk.”

The project is currently in Phase II and is funded by soybean farmers in Iowa and Illinois.

Phase I started in 1997 and ended in 1999. Phase II started in 2000 and will end in 2002.

Whether the project will continue after that stage will depend on the farmers themselves, he said.

“I think there will still be unanswered questions,” Tylka said. “But it is up to the farmers who administer the money.”