Signs of micronutrient deficiencies

Category: Grow Grain

Micronutrients are important too. Watch for these symptoms when scouting your field, and get to know your foliar options.

With all fertilizers, we want to have a plan in place to satisfy the crop’s nutrient requirement. The best plans start with soil testing, followed by field scouting. Watch for symptoms of micronutrient deficiencies this season so you can remedy them in season if possible and create an even more effective plan next season.

Here’s a quick rundown of some common symptoms and when they’re most likely to turn up.

Pig tailing eaves in copper-deficient wheat.

Copper (Cu)

Copper deficiency occurs in patches in the field, and we’re most likely to see symptoms in cereal crops later in the season. Here’s what to watch for:

  • The first symptom is pig tailing of the leaves – where the tip dries up and makes a skinny tail instead of a nice robust leaf.
  • Next, you’ll see aborted heads with only a few florets filled.
  • At harvest, when straight cutting wheat, watch for black patches in the field where nothing comes in the tank. While it might look like disease, very patchy fields can be the result of Cu deficiency.

There is a lot of talk about the relationship between copper and ergot. It’s important to note that just because you have ergot doesn’t mean you have copper deficiency. On the other hand, if you do have copper deficiency, it can increase your chances of getting ergot. A copper-deficient plant’s florets are open longer, which makes it more susceptible to ergot infection. 

Boron (B)

Boron deficiency is most common in canola. If you feel like you’ve applied adequate sulphur and there wasn’t too much heat, yet you still have a lot of blanks or short stubby pods, your plants could be short on B. A soil test will confirm that it’s nutrient deficiency, not temperature, that is affecting the crop. 

Broad bands of striped tissue on each side of a corn leaf's midrib – a sign of zinc deficiency.

Zinc (Zn)

Corn and pulses are the two crops most affected by zinc. Deficiency is common in corn on soils with less than 1 ppm or fields with excessively high phosphorus levels. It typically shows up in wet, cool soils or very sandy soils. Watch for broad bands of striped tissue on each side of the midrib of the leaf.  

In pulses, Zn levels have to be very low before symptoms show up. Watch for stunted plants with small leaves.

Foliar applications of micronutrients

In cases where we may have underestimated the crop’s nutrient requirements, or where something showed up that we didn’t expect, there are in-season foliar application options available for copper and boron.

Not all foliar products are created equal. Before you invest, talk to someone who understands the product options and how they compare in available nutrients. When you’re seeing a deficiency, or you’ve tested your soil and are worried about low levels of micronutrients, you want to make sure you’re getting enough nutrient on the plant to make a difference in yield. 

Talk to a Cargill agronomist about your product options. Fertilizer is an investment, and we can help you get the most from it. Start by thoroughly scouting your fields for micronutrient deficiencies this season. Together, we can make a plan to match next season’s fertilizer application to your yield goals.

Make sure to check out last week’s blog post on macronutrient deficiencies.

Tags: Agronomy, Fertilizer, Wheat, Canola, Corn, Cereals, Pulses

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