Peanut

{Arachis hypogaea}

Boron Deficiency in Peanut

Boron is critical to peanut quality. While boron fertilization may only occasionally improve peanut yields, it almost always is necessary for the prevention of “hollow heart” and other concealed disorders that severely reduce crop value.

Peanuts need a constant supply of boron during all stages of growth, but especially from flowering to harvest. Fertilizing with boron will help peanuts:

  • Improve root nodule development for more nitrogen fixation and protein production
  • Produce and retain more flowers and pegs
  • Enhance calcium utilization
  • Move sugars and protein from leaves to nuts
  • Prevent “hollow heart”

Symptoms of boron deficiency are particularly evident in the nuts and are not frequently found on the foliage under field conditions. While the effects on yield may be slight, the deficiency can markedly reduce the quality of the crop and the yield of marketable peanuts. The main symptom is of a hollow darkening of off-color area in the center of the cotyledon. The depression may vary from being shallow and slightly colored to being deep and dark brown according to the severity of the condition. Cracks may also develop on the pods.

The first sign of boron deficiency on the typically dark green leaves will be the development of water-soaked areas which give the leaves a mottled appearance. Prolific secondary branching occurs on short woody stems after dieback of terminal growing points.

When boron deficiency is less severe, flowers are not followed by any fruit development, possibly as a result of pollen tubes failing to grow properly. When boron deficiency is extremely severe, flowers do not develop.

How much boron is enough?

  • Peanuts are typically grown in light, sandy, well-drained soils, which are inherently low in organic matter, including boron.
  • Since boron is also readily leached from these soils, small annual boron applications are recommended to ensure an adequate crop supply during each growing season.

Your boron fertilizer options

  • Granubor® 2 is an ideal material for dry blends applied broadcast preplant or surface banded.
  • Fertibor® works best in fertilizer suspensions for preplant broadcast or band sprayed over the row.
  • Solubor® allows you the most flexibility for applying boron. It can be dissolved alone in water or in liquid fertilizers and/or pesticides, then applied to the soil or directly onto the foliage.*


*Foliar sprays should not exceed 0.5 lbs/acre boron per application.

Soil Application (Suggested rates of application)

  Granubor 2 Fertibor
LBS./ACRE 2-3 2-3
KG/HA 2.25 - 3.38 2.25 - 3.38

Foliar Application (Suggested rates of application)

  Solubor
LBS./ACRE 1-2
KG/HA 1.125 - 2.25

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 500 customers with more than 1,700 delivery locations globally. We supply 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles east of Los Angeles.  Learn more about Rio Tinto

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