Ask an Agronomist
How useful is manganese to soybeans?
Dec 02, 2011
Question: I hear mixed reports about manganese use in soybeans. Do you have any research on its usefulness for beans?
Answer:We are seeing response vary by soil types. In sandy soils, the yield response has been smaller, and sometimes nonexistent, says Farm Journal Associate Agronomist, Missy Bauer. “In muck and peat soils—which, in my area of south-central Michigan, tend to be spots within fields—it makes it difficult to measure the yield response,” she says. “But tissue tests show we have improved manganese uptake by the plants.”
In mineral soils in central Illinois, Farm Journal Agronomist Ken Ferrie says he has “really struggled” to get a yield response to treatments.
“Tissue tests show I get manganese into the plants, but I don’t always get a yield response at harvest,” Ferrie says. “I also have seen one replication of a trial respond to treatment, a second replication show no response and a third replication actually go backward.”
Deficiencies occur because manganese gets tied up, or fixed, in soil, Ferrie explains. So—except for rare situations involving certain very light soils—foliar treatments, rather than soil applications, are required.
Foliar applications of 1 lb. of actual manganese in 30 gal. of water per acre will alleviate deficiency symptoms and improve growth. If you apply a lower rate, regardless of the source, you often will need a second application.
Bauer advises her clients to take a proactive approach. “We don’t like to see deficiency symptoms appear,” she says. “Think about your field’s history. If you have had manganese deficiencies in the past, you probably will have them again the next time the field rotates back to soybeans.”