Corn School: Hideous cobs? It could be boron deficiency


Have you ever discovered small, misshapen, poorly pollinated corn ears mixed in with a field of impressive, high-yielding cobs?

PRIDE Seeds agronomist Drew Thompson received a call in August from a grower telling just this story. When Thompson visited the field he noted that no nutrient deficiencies were apparent (no firing or discolouration) so out came the shovel. Digging up plants with both good and poor cobs revealed a uniform seed placement of two inches, and all plants had roots growing out at a near perfect 35-degree angle.

Closer examination of the plants with the misshapen ears revealed that they were typically shorter, thinner stalked, and had smaller tassels. As he inspected the tassels, Thompson was surprised to see that quite a few of the glumes had not opened and no anthers had emerged. The kernels of the poor plants were also much less mature than those on the good plants.

It was a head-scratcher, but after digging through the scientific literature, Thompson found the answer – boron deficiency.

In this episode of RealAgriculture’s Corn School, Thompson shares what he’s learned about how growers can identify and diagnose boron deficiency in their fields. Many growers often attribute boron symptoms to insect damage or other environmental conditions, but Thompson believes many of these instances could be attributed to boron shortfalls. Story continues after the video.

Boron is a micronutrient that plays a role in cell growth and development and is especially crucial for the development of the ears and tassel; it’s needed at the growing points – meristems – where the reproductive components of the plant form.

In the video, Thompson offers tips on how growers can use tissue tests to confirm a boron deficiency diagnosis. He notes that the field with the misshapen ears had been planted late and ears were still quite small when the area experienced a stretch of hot, dry weather (late June to late July).

Realizing what can happen to a corn crop with sub-optimal boron levels and accepting the fact that hot and dry spells are getting longer and more frequent in Ontario, Thompson believes growers need to better understand how to work this nutrient into their fertility programs.

Click here for more Corn School episodes.

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Corn School (view all)Season 7 (2018) Episode 5

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