Soybean Chlorosis Ratings Available on Web

North Dakota State University researchers have screened over 150 soybean varieties for resistance to iron chlorosis and now have made the ratings available on the Internet.

According to Jay Goos, professor of soil science at NDSU, iron deficiency chlorosis is a common problem in soybeans grown on high pH and poorly drained soils.

"For soybeans that are solid-seeded, variety selection is the only practical control measure available. Foliar sprays have not given us a consistent benefit," Goos says.

"For soybeans planted in 30-inch rows, we have also shown that heavier seeding rates are helpful, but variety selection is still the most important control measure," he says.

For soybeans planted in 30-inch rows on chlorosis-prone soil, Goos recommends a final stand of about an inch between plants, or about 200,000 plants per acre.

For the past 18 months, with financial assistance from the North Dakota Soybean Council, Goos’ research team has been screening soybean varieties for resistance to iron chlorosis.

"We have screened over 150 varieties, and we can give only about 15 percent of them a ‘resistant’ rating," says Goos. "About half the varieties we have tested are ‘moderately susceptible’ or ‘susceptible’, so a farmer with chlorosis-producing land needs to choose varieties carefully."

Goos has made the current list of chlorosis ratings available on the Internet at www.soilsci.ndsu.nodak.edu/yellowsoybeans/index.html. The list is also available from the NDSU Department of Soil Science.

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Source: Jay Goos, (701) 231-8581, rj_goos@ndsu.nodak.edu
Editor: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu