Nutrient Management Research Database

Fertilizing Young Almond Trees

This video describes research on fertilizer type and application rate conducted in Merced County almond orchards by Pomology Advisor David Doll.  Trials were conducted on 2 sites within Merced, on loamy sand and sandy loam soils.  Results of the research are presented and  the practical implications of tree density, microsprinkler wetting patterns, soil and water nitrate content and projected yield on how much N should be applied are discussed.

This video describes fertilizer type and rate trials conducted at 2 almond orchards in Merced County by Farm Advisor David Doll.  

Fertilizer source trials:

• N was sourced as ammonium, nitrate, or blends.
• Applied as granular multiple times throughout the year at 4ozs N/tree.
• Growth was measured and tissue was analyzed for nitrogen, phosphorus, potassium, calcium, zinc, boron and manganese contents.

Fertilizer rate trials: 

• Conducted on a sandy soil.
• N was sourced using  a controlled release blended triple 15 granular fertilizer.
• Application rates of 0,1,2,4 and 6/ozs of N/tree with split applications were implemented.
• Tree growth was assessed.

• On the loamy sand soil, seasonal growth with Triple 15 was significantly larger than the Calcium Nitrate fertilizer, while on the sandy loam soil, no differences in seasonal growth between fertilizer types were observed.
• There were no significant differences in the percentage of N in leaf tissue between fertilizer types, with the exception of slightly lower N content in leaf tissue from calcium nitrate plots.
• Treatments where ammonium sulfate was applied resulted in higher leaf tissue concentrations of zinc, indicating that change in soil pH due to the acidifying properties of some fertilizers can change micro nutrient availability.
• In the fertilizer rate trials, the maxim change in trunk diameter occurred between 3 and 4 ounces of N/tree.