Growing almonds in the US

Many almond growers across California employ integrated nutrient management approaches, which combine fertilizer applications with other agronomic practices such as cover cropping, crop rotation, and soil amendments. This holistic approach aims to optimize nutrient cycling, enhance soil fertility, and minimize environmental impacts while maintaining or increasing almond yields.

• With increasing consumer demand for organic and sustainably grown almonds, many growers in the US are adopting organic fertilizer sources, like Polysulphate® (polyhalite)
• Almond growers in California, where water quality is a significant concern, prioritize water quality, employing strategies like controlled-release fertilizers, precision irrigation, buffer strips, soil surfactants and vegetative filter strips to minimize nutrient runoff and protect water resources.
• Nitrogen is a critical nutrient for almond trees. Growers employ various practices to optimize nitrogen use efficiency (NUE), such as split applications, and fertigation (fertilizer application through irrigation systems). Nova Elevate, for example, is a micronutrient foliar solution that contains high amounts of Molybdenum to help improve NUE. As a highly soluble source of cobalt and molybdenum it’s a good fit for mitigating stress in high-value specialty crops like almonds. Likewise, Polysulphate trials on almonds in California show improved NUE.
• California almond orchards face challenges due to the variability of potassium levels and the influence of moisture on tree utilization. Effective management of potassium levels is crucial for maintaining optimal tree health and maximizing yield. Trials in Sanger, California show that Agrocote  (a high K controlled release fertilizer) was effective at increasing tissue K content without leaving excess in the soil.
• Nutrient management, including post-harvest applications of gradual-release fertilizers, like Polysulphate, is critical for the sustained health and productivity of almond orchards over the years.

What soil type, pH and climate do almond orchards prefer?

The Mediterranean climate of California, characterized by hot, dry summers and mild, wet winters, is well-suited for almond cultivation. Since almond trees require a period of winter chill for proper dormancy and spring bloom, California’s climate is conducive to their growth.

• Almonds are grown in soils with pH levels from 6.7 to 8.4, and thrive in slightly acidic to alkaline soils
• Ideally, almond trees prefer deep, well-drained sandy loam and loamy soils with good water retention to support their deep root systems
• To optimize nut yield we need to maximize healthy populations of productive spurs each year.
• Adequate nutrition, moderate temperatures, limited wind and precipitation during bloom influence pollinators and nut set.
• Flowering/early fruit set and mid-summer bud formation are critical periods for tree productivity.
• Abiotic stresses like deficit or excess precipitation, high or low temperatures influence yield, and regions such as the San Joaquin Valley, provide an excellent combination of ideal factors
• Many almond orchards in California use efficient drip irrigation systems to provide water directly to the root zone, promoting water efficiency and minimizing the risk of diseases and allowing for successful fertigation practices

What nutrients are most important for almond yield and quality?

Balanced nutrition is key for optimal plant growth, including yields and quality. Ensuring adequate supply of macronutrients, nitrogen (N), phosphorus (P) and potassium (K), is essential. However, paying attention to secondary macronutrients, such as calcium (Ca), magnesium (Mg), and Sulfur (S), as well as key micronutrients like boron, and zinc is essential to meet crop needs from fruit set through to harvest.

• Nitrogen and potassium adequate levels are critical for high-yielding almonds 
• Micronutrients are essential for enhancing almond production through improved nitrogen-use efficiency, stress mitigation, and increased yield
  • Molybdenum supports efficient nitrogen utilization, aids in flower formation and fruit setting, while also enhancing chlorophyll production in leaves.
  • Cobalt plays a vital role in regulating oxygen and ethylene production, preventing premature crop maturation, and optimizing nutrient uptake for potential yield.
• Zinc and boron are needed the most at bloom. (Univ. of CA Franz Niederholzer et al. May 2022).

Nutrient Requirements:  

Nutrient balance is key to quality yields.  

This is the Estimated Almond Nut Nutrient Removal plus 20% for root, shoot, tree growth, losses etc. for 2500 lbs./acre kernel yield:  

• N lbs./acre = 210-275 P2O5 lbs./acre = 50-70  
• K2O lbs./acre = 225-300  
• S lbs./acre = 8-11  
• Mg lbs./acre = 10-15 Ca lbs./acre = 10-22  

Almonds export around 80 lbs. K per 1000 lbs. of harvested product. With yields from 2500-4500 lbs. acre per year, K offtake in harvested product can range from 200-360 lbs. K/acre/year (Dr. Patrick Brown, UC Davis).  

• Apply N from March to June with some early, peak uptake in April/May and slowing down by June.  
• Nutrient removal of 90-100 lbs. K2O and 23 lbs. P2O5 per 1000 lbs. of kernel crop.  
• Post-harvest foliar applications of zinc and boron for loading buds prior to dormancy.  
• Post-harvest K and other nutrients (based on tissue and soil analysis) to set the trees up for yield the following year. 

Role of Nutrients:

Key quality and yield parameters can be affected by different nutrients. See how they can influence your harvest. 

+ = improving 

– = decreasing 

+/- = different results, depending on the rate of nutrient applied 

Yield and Quality positively influenced at the right rates:

• N++
• P+
• K+++
• Mg+
• Ca++
• S+