Be Almond Wise: The Need for Nitrogen

Proper nitrogen (N) management is crucial for orchards once the trees break dormancy. Depending on the post-harvest nutritional applications and stored reserves, an almond orchard needs supplemental nutrients in order to produce a healthy crop load without stressing the tree. Nitrogen-deficient trees will show symptoms, including reduced shoot growth, inadequate foliage and small yellow leaves early in the season. However, too much N can prompt an increase in disease severity (hull-rot).

The need for N in almond trees is most prevalent starting at bloom and lasts through June. Monitoring N levels through tissue sampling is critical. With a leaf tissue sampling system in place, one can take a representative sample of an almond block and prescribe the ideal N application(s) and program to fit that orchard. Studies show 2.2-2.5% N level in tissues in July attribute to sufficient N managment. Tissue sampling should start in March, post-bloom, to make the first N adjustment if needed. Tissue sampling methods vary among consultants, but follow-up samples should be taken again in April and May (approximately 30 day intervals) to monitor N levels and make needed adjustments prior to nut-fill.

It is recommended that approximately 20% of total N be applied during spring flush, which takes place from bloom through leaf expansion. The next 30% of N can be applied between full leaf expansion and shell hardening. Another 30% between shell hardening and early hull-split, and the final 20% from hull-split through post harvest. These recommendations are based on an almond fertilizer model provided from the research of Dr. Patrick Brown and his colleagues at UC Davis.

Helena offers several foliar N products to help set your orchard up for maximum production. To build a program tailored to your orchard, Helena consultants can determine N application rates based off of orchard production history and estimated yields for the upcoming season. Coron 25-0-0 works well throughout the season, providing superior foliar fertility and excellent tank mix compatibility (1 to 4 qts/acre). In addition, ENC is an 11-8-5 NPK formulation providing a proven balance of nutrients and EDTA-chelated minor elements designed for quick plant uptake. Our foliar nutrition recommendations include products from Helena’s Brexil and Ele-Max lines to help correct elemental deficiencies other than N.

Ensure your trees are well fed from bloom, to nut fill, and through hull-split. For more application recommendations and to create your Almond Wise program, contact your local Helena representative.

- James Schaeffer, Western Division Product Specialist

1.    Brown P., Muhammad, S., Saa Silva, S. Development of Leaf Sampling Methods & Nutrient-Budget Fertilization.

2.    Brown, P.H., Zhang, Q., Stevenson, M., Rosecrance R.C. Almond Nitrogen Model.