Drought Management in Almonds around the World

Almond growers got a peek at irrigation strategies used under drought conditions in Australia and Spain at the Almond Industry Conference, comparing them to the latest research results on drought irrigation management in California.

Ben Brown, industry liaison manager for the Almond Board of Australia, reported that chronic water shortages Down Under have steered growers to adopt drip irrigation on 90% of the acreage. Some of the lessons the Aussie growers learned while addressing drought conditions are:

• Almond trees are hardier than expected, bouncing back after a year of stress.
  
  
• Don't stag-horn prune. It takes trees too long to return to production.
  
  
• It's possible to produce 2,750 lbs/A on 37 inches of water, where normally growers apply a minimum of 49 inches.
  
  
• Cutting back on water in a sprinkler irrigation system is not as successful in terms of yield as it is on drip.

Presenting a report on conditions in Spain, Butte County Farm Advisor Joe Connell said that although there are over 1.3 million acres of almonds, the plantings are predominantly dryland, scattered in small plots of a few trees and intermingled with olive trees. Less than 8% of the trees are irrigated, and most of that is on drip. "They underirrigate to only 60%-80% of crop ET," he said, and yields are only 250 lbs-400 lbs/A.

The new trend in Spain is to focus on "ecological farming," selling almonds as organic. "They make close to zero applications of any inputs, including fertilizer," he said.

Bruce Lampinen, integrated orchard management specialist at UC Davis, described how scheduling irrigation can affect yields, pest management, crop quality and food safety.

For efficient production of almonds, he said, it is essential to manage water (and the tree canopy) effectively. One of the most important decisions a grower has to make is to decide when to start irrigating in the spring, and this decision should be made on the basis of plant and/or soil moisture readings—or both.

Although research shows a positive relationship between canopy size and yield, a heavily canopied orchard with high yields comes with a tradeoff of increased food safety risk. For instance, shaded areas near the drip lines create conditions conducive for Salmonella growth. And overirrigating can certainly lead to root anoxia and diseases resulting in decreased tree performance and yield.

For information on water issues, visit almondboard.com/waterways.