4 Reasons Your Soybeans Turned Yellow

July 8, 2016 12:22 PM

Yellow soybeans? That probably isn’t a good sign. What’s happening, exactly?

Dorivar Ruiz Diaz and Ignacio Ciampitti, Extension specialists with Kansas State University, recently discussed four potential culprits in a recent edition of K-State’s “Extension Agronomy eUpdate” newsletter. Here’s what may be happening in those particular fields.

1. Nitrogen deficiency. This may be due to a delay in rhizobial nodule development because of extreme wet, dry or hot conditions. Check lower leaves – if they’re pale green or chlorotic, N deficiency may be the reason. Soybeans that are double-cropped after wheat are also susceptible, and even hail-damaged soybeans are at risk if enough foliage was injured.

2. Iron chlorosis. If soils are overly saturated, temporary symptoms of iron chlorosis is a potential result. Topmost leaves will turn yellow while veins remain green. Highly alkaline pH soils are most susceptible.

3. Potassium deficiency. Unlike iron deficiency, K deficiency is more common later into the season. Look for irregular yellow mottling around leaflet margins. It’s a problem most common when soils are too wet or too dry. Good root growth will solve these problems, unless there’s a true K deficiency.

4. Rooting restrictions. Any number of issues – including wet or dry soil, compaction problems, or even root insects and diseases – will adversely affect growth and could lead to yellowing. “With a restricted root system, the growing plant can’t access the nutrients it needs to make more leaves,” the researchers note. “As a result, nutrient deficiencies can show up in fields where you [otherwise] might not expect them based on a typical soil test.”

Click here for more information about these potential problems.

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Spell Check

David Doyle
La Salle, IL
8/22/2016 09:58 AM

  Thanks for the info on yellow soybeans

Baker, FL
7/26/2016 05:45 PM

  Maybe, just maybe it could be from glyphosate. Roundup applications later on beans cause a lot of yellowing. We have found that foliage Manganese can mitigate this yellowing. Not sure if it changes the economics but it sure makes the look better. I'm kinda surprised this was not in your top 4.


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