Influencing Almond Health

Nutrients and Disease Tolerance

There is strong evidence to link good crop nutrition with improved tolerance to disease. The effects are largely due to cationic nutrients – most notably potassium and calcium – improving tree and nut integrity and strength.

Potassium maintains good growth and strong nut fill, while calcium has a direct effect on strengthening cell walls and maintaining cell membrane integrity, helping prevent cell breakdown and disease ingress. Calcium can also help trees resist fungal or bacterial infection by suppressing the extra-cellular enzymes these pathogens secrete.

Fertilizer Application Principles

It is important that soil pH be adjusted to the optimum range to ensure ideal soil conditions. Use lime to raise the soil pH, or acid-forming materials to lower the soil pH, as appropriate. Adequate levels of phosphorus are also needed within the root zone prior to planting.

In established groves, dry applied fertilizers can be broadcast across the surface, but are best applied banded underneath the canopy drip line or within the irrigated zone at a time that matches crop need. Fertigation provides nutrients more directly to the active root zone and is a more effective means of meeting immediate needs.

Drip systems provide a zone of moisture within which roots flourish. Well designed and properly operated low-volume irrigation systems can provide more uniform application of water and nutrients, allowing the right nutrients to be applied at the right time to satisfy requirements. In almond production, fanjets are more efficient than drip systems.

Foliar application is used to meet immediate nutritional needs and is particularly effective at targeting developing leaf, bud and flower tissues.

Common practice in nut trees is to use foliar boron and zinc prior to leaf senescence in the autumn to build reserves in buds that will ensure good flowering and fruit development in the following season.