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Boron Deficiency in Corn

Boron is a key element in plant nutrition. University researchers have found yield increases ranging from 9 to 37 bushels of corn per acre where boron was added. Corn requires high levels of all nutrients to ensure maximum economic yields.

Boron is necessary for:

  • Stimulation of root and shoot development
  • Tassel and silk formation
  • Movement of sugars from leaves to ears
  • Pollen germination
  • Pollen tube growth and seed formation
  • Better water use efficiency and drought tolerance

Irregular distribution of kernels and a general reduction in growth are the first signs of boron deficiency. Severe boron deficiency results in short bent cobs of corn with under-developed tips and very poor kernel development. Yellow or white spots develop between the veins on young leaves, and the spots often coalesce forming streaks. These streaks, which may be waxy and raised from the leaf surface, do not normally develop on fully grown leaves. The leaf tips may be curled. There is also a shortening of the internodes and often the young leaves fail to open. There are indications that high-lysine corn is more susceptible than normal corn to boron deficiency.

How much boron do you need to correct boron deficiency in corn?

  • Corn removes significant amounts of boron from the soil each year. In high yield situations, boron fertilizer requirements become critically important. Most universities recommend boron at planting, in sidedressing, or fertigated for irrigated corn.
  • Rates of boron fertilization for corn should be based on yield goals along with soil tests and/or plant analyses.

Timing your boron application

  • Boron may be applied in dry bulk blended fertilizer, broadcast before planting, using Granubor®
  • Boron in liquid suspensions may be applied broadcast before planting, banded at planting, or sidedressed, using Fertibor® in suspensions
  • Boron in liquid fertilizers may be broadcast before planting, banded at planting, sidedressed, or fertigated, using Solubor®
  • Boron for high-yield, irrigated corn may be applied most conveniently through the irrigation system as Solubor four to six weeks after emergence in two applications up to one pound each
  • Never apply boron in direct contact with the seed
Key Finding
Field data for boron and corn

U.S. Borax Products for Corn

15% Boron |  | OMRI Certified
Optimum product for suspensions

A fine crystalline borate ideal for NPK compound fertilizers and suspensions. Manufactured as free-flowing granules, Fertibor is easily handled and offers superior flow and consistency.

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15% Boron |  | OMRI Certified
Made especially for bulk blenders

A pure, 100% water-soluble micronutrient that meets boron demand during the growing season. Made especially for bulk blenders, Granubor helps to ensure uniform distribution in nutritional blends and in the field.

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20.5% Boron |  | OMRI Certified
Product of choice for foliar applications

A concentrated, highly soluble, and fast dissolving powder that is ideal for foliar and other sprays. With the highest concentration of boron in any approved product, Solubor is an economical choice for nutritional formulations.

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20.8% Boron
Boron for fertilizer manufacturing

This refined U.S. Borax product is made from the dehydration and fusion of borax. Depending on the grade, Anhybor can be used to produce boron-enriched compound fertilizers or to coat different fertilizer products, such as NPK blends with the aid of a binder.

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10% Boron
Solubor Flow
For fertigation or hydroponic growing

First and only aqueous suspension of sodium borate microcrystals.

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14.5% Boron | 29% Zinc
Perfect combination of zinc and boron

Because zinc and boron deficiency are widespread around the world, a product with both nutrients is a good fit in many regions. Zincubor brings these two important micronutrients together in one product.

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Calculate Your ROI

Soil Application (Suggested rates of application)

  Granubor Fertibor
LBS/ACRE 4.46 - 9.0 4.46 - 9.0
KG/HA 5.0 - 10.0 5.0 - 10.0

Foliar Application (Suggested rates of application)

KG/HA 2.0
Value in Use
Current Yield (Per Acre)
Expected Sale Price

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles. Learn more about Rio Tinto.

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