Thanks to ISU researchers, the nation may see an increase in soybean yields.

Work to increase soybean yields began in 1997, when a group of farmers from Iowa and Illinois met with several researchers to determine what limits soybean yields, said Bill Batchelor, project coordinator for the Yields Project.

The Yields Project continued for three years, but researchers still had unanswered questions, he said.

In 1999, researchers from Iowa State, the University of Illinois and the Soybean Research and Development Council met to create a project to increase soybean yields.

This project, Yields II, was a follow-up of specific questions raised from previous projects, Batchelor said.

Researchers from Iowa State, the University of Illinois and the University of Wisconsin took part in the Yields II Project, which concluded in spring 2003.

The project was to determine if interactions among genetics, diseases, weather and tillage can be controlled through management, Batchelor said.

The researchers found that soybean yields are reduced each year because of different factors, he said. Some include soybean cyst nematodes, Sudden Death Syndrome, Brown Stem Rot and water stress.

Soybean Cyst Nematodes are worms that live in the soil and feed upon the soybean roots and reduce yields, said Greg Tylka, professor of plant pathology.

“They are found in higher numbers where there is higher pH in the soil, and they cause more damage in dry soil because the plants are suffering from a lack of water,” Tylka said.

Sudden Death Syndrome rots the roots and kills the plant within a week or two, Tylka said. This doesn’t become apparent until later in the season, he said.

Fungus living in the soil infects the roots of the soybeans and travels to the stem and leaves, causing Brown Stem Rot, Tylka said.

Tylka said the three diseases cannot be prevented, but they can be managed.

“Resistant varieties are available for Soybean Cyst Nematodes and Brown Stem Rot,” Tylka said.

“There really aren’t any resistant varieties for Sudden Death Syndrome, although some varieties do get less of it than others.”

The research also found that Brown Stem Rot levels decreased as the soil pH increases.

Plant responses to various factors are caused by the amount of rainfall. The research showed, however, that if a plant receives adequate soil moisture when it flowers and the pods fill, it can recover from various stresses and lead to higher seed numbers.

The Yields II Project also established a Web-based tool, CROPGRO, to allow producers to set up field conditions to establish the effect disease will have on their own fields, Batchelor said.

“In 1995, the No. 1 goal of the Iowa Soybean Promotion Board was to increase soybean production to 3 billion bushels nationally,” he said.

Demands for soybeans are high because they are a direct substitute for fossil-derived products, Batchelor said.

The demand for soybeans currently exceeds the United States’ ability to supply them.

He said the Iowa economy would benefit greatly from an increase in soybean yields.

“If there is a 30 percent increase in soybean yields, it would mean more money in farmers’ pockets,” Batchelor said.

Batchelor said soybean prices were nearly $10 a bushel in February and March 2004, but these prices have decreased recently because Brazil had good crops.