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.