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Boron (B) is a micronutrient that is essential for cell wall formation and rapid growing points within the plant, such as reproductive structures. Interestingly, while higher plants require B, animals, fungi and microorganisms do not need this nutrient.

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Boron improves seed set under stressful conditions.

Quick Facts

Although required in small amounts, boron is a component of all cell walls in the plant.

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Boron deficiencies are more pronounced during drought periods, when root activity is restricted.

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The line between deficiency and toxicity is narrower than other essential nutrients. Farmers should apply at proper rate and with proper placement.

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Corn most effectively uses boron when it's applied through broadcast soil applications.

Dig Deeper: Fertilizer Use Guide

Boron (B) exists primarily in soil solutions as the BO3-3 anion – the form commonly taken up by plants. One of the most important micronutrients affecting membrane stability, B supports the structural and functional integrity of plant cell membranes. Boron-deficiency symptoms first appear at the growing points, and certain soil types are more prone to boron deficiencies.

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Deficiency Symptoms

Symptoms of deficiency can vary across crop species, but similarities exist for how nutrient insufficiency impacts plant tissue color and appearance. Nutrient deficiencies are commonly associated with the physical location on the plant (i.e., whether the symptoms are primarily observed on older versus newly formed plant tissue), but these symptoms can spread as the severity of the deficiency progresses.

All photos are provided courtesy of the International Plant Nutrition Institute (IPNI) and its IPNI Crop Nutrient Deficiency Image Collection. The photos above are a sample of a greater collection, which provides a comprehensive sampling of hundreds of classic cases of crop deficiency from research plots and farm fields located around the world. For access to the full collection, you can visit IPNI's website.