Iron deficiency chlorosis in soybeans mostly in the Platte and Elkhorn River Valleys
This is Dr. Nathan Mueller, your local agronomist for Nebraska Extension. I spent 3 years, from 2009 through 2012, as a PhD student researching starter and foliar micronutrient applications in corn and soybeans. I always enjoying discussing when and where we need micronutrients. Let’s answer two questions for you over the next minute or two. First, what micronutrients are worth applying in Northeast Nebraska? Second, are certain crops more likely to respond to micronutrient applications?
Zinc, Copper, Manganese, Iron, Boron, Chloride, Nickel, and Molybdenum are all plant essential micronutrients. So plants need these nutrients to grow and thrive. Here in the Northeast Nebraska, deficiencies have not been found for Copper, Manganese, or Nickel for any of the crops we commonly grow. I like to point out that an article you may read about copper deficiency found in Kentucky does not mean you should be concerned about it here. Micronutrient deficiencies are very regional in nature.
So our list is now down to Boron, Chloride, Molybdenum, Zinc, and Iron. Boron deficiency is very rare here and may occur in high pH sandy soils during drought conditions. The only crop I consider a boron application for is during alfalfa establishment. To reiterate my point again, agronomists have found boron deficiency in soybeans grown in Arkansas following rice. This does not mean we have a boron deficiency in Northeast Nebraska nor do we grow rice before soybeans.
Molybdenum deficiencies are very rare and maintaining soil pH above 5.5 with lime for soybeans is the most practical solution. So don’t apply molybdenum, apply lime. Yield responses to chloride in wheat, grain sorghum, and corn have been documented in Kansas. If you are remotely worried about chloride deficiencies, apply potash, our most common potassium fertilizer, also called potassium chloride, at 40 lbs/acre ahead of your corn crop this spring.
Iron deficiency chlorosis in soybeans and zinc deficiency in corn are the two micronutrients we need to evaluate more closely. To learn more about iron and zinc, tune in next week at the same time to learn more.
In summary, there are many cases where micronutrients are simply not needed and just won’t pencil out. For more information on micronutrients in Northeast Nebraska, contact me at 727-2775 or listen to this radio message again on our website at croptechcafe.org. Know your crop, know your tech, know your bottom line. This is Dr. Nathan Mueller, your local agronomist for Nebraska Extension on KTIC radio.
