A comprehensive non-phosphite foliar program in almond trial demonstrates significant yield increases three years in a row compared to the standard fertility program. Increased tree growth was also acheived.

ESCALON, CA – A multi-year trial by a leading independent research contractor, Brooks Bauer, (Two Bees Agricultural Research & Consulting) has found that the Agro-K non-phosphite foliar and soil nutrient program produced statistically significant increases of almond nut meat yield, tree growth, and overall tree health.


Nut meat yield increased 486lbs, 514lbs and 1,017lbs./ac in 2015, 2016 and 2017 respectively compared to the grower standard nutrient program. (see graph below)   Significant increases in trunk diameter indicated that the growth of the trees improved as well in comparison with the grower standard nutrition program.


“The trial demonstrated that producers can improve nut meat yield and tree health while still complying with tightened phosphite regulations in some parts of the world markets,” says Dr. Richard Warner, Research Director of based in Clovis California for Agro-K Corporation.



“The trial began in 2015 in response to continuing concerns about the use of phosphite-based inputs in almonds and other nut crops as a result of European Union regulations,” Dr. Warner says. “With 2017 completed we now have data for three years with the same fertility program on the same trees in the same block. The average yield gain over these three years was 670 pounds/acres meaning an extra grower return of about $1,800/acre per year on each of those acres. The consistency of the yield gains over the three-year trial clearly demonstrates Agro-K’s products and science driven nutrient program gives growers an excellent ROI.”


The independent contractor Brooks Bauer of Two Bees Agricultural Research and Consulting, of Escalon, California, selected for the trial a randomized complete block of 4-year-old Independence® variety trees. Multiple tree plots were replicated six times on 4th leaf (2015),  5th leaf (2016) and 6th leaf (2017). The foliar materials were applied with an air blast sprayer at 100 GPA. BioMax™ Dual Action + was applied to the top of the soil and watered-in as directed. Agro-K foliar nutrient materials were applied at the appropriate stages of crop development (including Pink Bud/Early Bloom, Full Bloom/Petal fall, post bloom, and Hull Split).



“The Agro-K non-phosphite program is meant to complement a soil nutrient program. This combination is the foundation for overall plant health and consistently high annual yields,” says Dr. Warner. “Maximizing profitability in an almond orchard starts with optimizing nut set every year. Achieving consistency in set and minimizing alternate bearing cycles is the key to consistent high yields and larger profits. Following the Agro-K program ensures that trees have the right nutrients at the right time in the right forms and right mix. We do not want the tree to lack for critical nutrients a key growth stages during the year.  If that happens, yields suffer.  Agro-K’s program is designed to prevent that happening and to maximize yields.”


The three-year trial involved Agro-K’s carbohydrate-based Dextro-Lac foliar line rather than Agro-K’s phosphite-based line. The trial has shown how almond tree vigor, overall health and increased nut meat production respond to a nutrient program based on these products:


  1. Vigor-SeaCal™, (a highly available calcium combined with Agro-K’s exclusive seaweed extract blend)
  2. Vigor-Cal-Bor-Moly™ (a Dextro-Lac® blend of calcium, boron and moly),
  3. Zinc Plus+4 Dextro-Lac® (a blend of zinc, magnesium, manganese, iron and copper).


BioMax Dual Action + is a unique soil fertility product. It is designed to increase the efficiency of ground-applied fertilizers by 1) promoting root growth and mass to maximize nutrient uptake, and 2) directly feed existing beneficial microbial populations such as Mychorrizae in the rhizosphere. This increases native beneficial populations and their activity helping maximize nutrient availability from ground-applied fertilizers. BioMax Dual Action + is specifically designed to improve ground fertility efficiency while increasing root growth, tree growth, and long-term yield enhancement.


Agro-K nutrient programs are based on a science-driven approach with a clear understanding of the almond tree physiology and the tree’s peak nutrient demands throughout the season. This means applying the right nutrient, at the right time, in the right form, at the right rate, in the right mix.


“Growers interested in maximizing yield and quality consistently, year-over-year.  The key to achieving this is meeting peak nutrient demand timings all season long so that the tree has the right nutrient reserves ready each year at each stage of nut and canopy development,” says Ken Dart, Agro-K’s National Technical and Marketing Manager. “Environmental dynamics vary each year, but you never want the tree to lack critical nutrients at critical physiological timings.”



Says Dart, “Foliar applied nutrients early season are needed to fully support the tree’s needs and to ensure better nut set, increased nut cell division for larger nuts and faster early growth with larger leaves that have more photosynthetic capability. As the season progresses, other foliar nutrient applications at key development timings like hull split will keep the tree on course for healthy growth and increased yield the following crop year.”


Dart cites these important nutritional facts:

  • The process of a tree breaking dormancy is a very zinc-intensive process.
  • Almond trees have a large early season demand for zinc to support leaf, root and vascular systems. All these tissues require zinc to function and grow fully and properly.
  • The best nut set and yields won’t happen without sufficient molybdenum for pollen production and pollen performance, and boron for pollen tube development and phosphate for cell division for good nut size.
  • Nut retention and nut size are dependent on large leaves with good chlorophyll. Leaf size is dependent on adequate zinc and phosphate levels while leaves are forming – (meaning early peak nutrient demand). One of the keys to good nut retention, nut size and increased yield is a hull split and/or post-harvest foliar application of zinc and macronutrients in a form that will be taken in, stored in these tissues and ready to use when dormancy breaks in the spring. These must be applied at hull split and or post-harvest the season prior.
  • Chlorophyll production takes place as the leaves expand and requires magnesium, manganese, iron, and sulfur. If these nutrients are deficient as chlorophyll forms leaves will not be as effective in capturing light for photosynthesis (especially in the lower canopy) which leads to fewer and smaller nuts, weak lower limbs and terminals that are more vulnerable to the complex of diseases leading to lower limb die back. Lower limb die back is becoming more and more of a severe problem and is causing significant yield reduction and shorter orchard stand life.


For more information on Agro-K’s almond trial research, fertility programs and Agro-K’s products contact your local Agro-K dealer or Agro-K today. Phone (800) 328-2418, visit www.agro-k.com, or email info@agro-k.com.


Independence is a registered trademark of Zaiger Genetics. BioMax, Vigor-SeaCal, and Vigor-Cal-Bor-Moly are trademarks and Dextro-Lac is a registered trademark of Agro-K Corporation.