Soybean School: Why Are My Soybeans Turning Yellow?


That’s a question many growers ask when they see parts of their soybean fields prematurely turning yellow in August and early September.

In this episode of Real Agriculture Soybean School, OMAFRA’s Albert Tenuta and University of Guelph researcher Dave Hooker team up to answer the question and provide management tips. When his phone rings, Tenuta says “growers are saying they’re noticing yield reductions in those areas and they want to know what they can do this year and in following years to reduce that yellowing.”

soy variability factors
University of Guelph’s Dave Hooker says a range of disease, environmental and agronomic factors can conspire to produce yellow soybeans and steal yield.

Hooker notes that yellow soybeans can be caused by a range of disease, environmental and agronomic factors – everything from herbicide stress, compaction and fertility problems to drought, poor drainage and disease.

“Is there fusarium? Is there sudden death syndrome? Soybean cyst nematode?” These are other questions growers need to ask, says Tenuta. “We have the tools to manage these, but you have to be aware of them.” The best way to do that is to get out and scout and dig up soybean plants in the affected areas.

Hooker adds that growers can also optimize yield potential by better managing environmental conditions. For example, improved soil health can increase water-holding capacity giving soybeans increased tolerance to moisture stress. Soil testing can also ensure that yellow spots are not fertility related.

“Check out those yellow spots now,” advises Tenuta. “What you learn can help you next year and beyond.”

Click here for more Soybean School episodes.

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Soybean School (view all)Season 5 (2016) Episode 12

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