{Medicago sativa}

Boron Deficiency in Alfalfa

Boron has been shown to increase yields and improve the quality of a wide variety of crops. Alfalfa, a common pasture crop, responds especially well to boron fertilizers.

Boron is an essential nutrient for all plants. Providing alfalfa with adequate boron is necessary for:

  • Greener, leafier plants with high protein
  • Faster regrowth after each cutting
  • Longer stand life
  • Improved winter hardiness
  • Enhanced root growth
  • Better water use, efficiency, and drought tolerance
  • Increased root nodule development for fixing nitrogen
  • Thicker stands to suppress weed and grass growth

Boron deficiency in alfalfa, in its mildest form, can easily pass unrecognized—it appears as a reduction in flowering and seed set. Such a mild boron deficiency is seldom detectable in hay yields from a single cutting. However, reduced flowering may delay cutting, and the result is a poorer quality hay. Eventually, the total quantity of this pasture crop may be reduced.

The main symptoms of boron deficiency are yellowing and reddening of the upper leaves. As the deficiency develops, the top stems progressively shorten and the short side branches give the plant a “rosetted” appearance. At this stage, the growing point becomes dormant or dies.

Boron deficiency is closely associated with moisture stress and drought. Alfalfa yellowing caused by boron deficiency is frequently mistaken for drought damage. Flowering is often reduced and the flowers fall before setting seed. Boron deficiency symptoms look different than leaf hopper injury, potassium deficiency, and certain diseases, all of which cause yellowing of both the lower and upper leaves. With boron deficiency, the yellowing is confined to the upper leaves; it does not occur randomly, as is the case with leaf hopper injury.

Spotting Boron Deficiency in Alfalfa

How much boron is enough?

Use these guidelines:

  • Alfalfa removes higher amounts of boron from the soil each year than any other crop
  • Most universities recommend applying boron fertilizers at stand establishment, and annually thereafter, after each cutting
  • Rates of boron fertilization should be based on yield goals, along with soil tests and/or plant analyses
  • The Key Findings chart gives general application rates for boron fertilizers

Timing your boron application

At establishment: ​

  • Boron can be applied and incorporated with other fertilizers and/or chemicals prior to planting in the fall or spring
  • Broadcast applications are more economical with Granubor® in dry blends, or Fertibor® in suspensions
  • Where leaching or companion crop tolerance are of concern, higher recommended rates of boron should be split, with the majority applied after the first cutting in the establishment year
  • Never apply boron with the seed at planting

Fertilization of alfalfa

Recommended lbs of boron per acre per year:

Potential yield
Application methods Boron soil test rating
    Low Medium High
1 to 3 Prior to seeding 1 0 0
  Topdress 1 1 0
3 to 6 Prior to seeding 2 1.5 0
  Topdress 2.5 2 1
Plus 6 Prior to seeding 3* 2.5 1
  Topdress 4* 3* 1.5

Annual topdressing

Use these guidelines:

  • Alfalfa needs a relatively high rate of boron constantly over the entire growing season
  • Annual boron applications should be applied when other nutrients are topdressed, after cuttings
  • If no other fertilizer is applied due to manuring, boron needs of alfalfa can be met with Solubor® sprayed on the stubble after any cutting, or in any spray operation*
  • Because alfalfa will take up more boron than it needs for a single cutting, split applications of high rates are more economical and efficient
  • Since boron availability is reduced during dry periods, and because adequate boron improves winter hardiness, most growers apply boron after the first cut in the spring and the last cut of summer

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

Key Findings
Yearly boron vs alfalfa yield

U.S. Borax Products for Alfalfa

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.

Learn more →

Calculate Your ROI

Soil Application (Suggested rates of application)

  Granubor Fertibor
LBS/ACRE 6-24 6-24
KG/HA 6.75 - 27.00 6.75 - 27.00

Foliar Application (Suggested rates of application)

KG/HA 4.5 - 10.125
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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