Almond Trees Can Tolerate Drought – But It Comes with a Price

With Californians urged to use water wisely, many Valley residents are planting drought tolerant landscaping. Communities such as the City of Clovis in Fresno County even publish approved lists of drought tolerant plants.

Desert willow tree is good for drought-tolerant landscaping.

Desert willow, cuayamaca cypress and coast live oak are among the trees listed as very low water users. Perhaps, we should suggest adding the almond tree.

Yes, almond trees can tolerate drought conditions. In fact, these trees can survive on as little as 7.6 inches of water annually, according to a February 2015 University of California Agriculture and Natural Resources report called “Drought Management for California Almonds.”

Of course, there’s a huge difference between a desert willow and an almond tree. A water-stressed willow won’t hit a farmer’s pocketbook like a thirsty almond tree.

Alas, drought survival comes with a price.Less water reduces growth and yield. Ideally, almond trees need 54 to 58 inches of water for maximum production.

“If you’re cutting your third or fourth year of deficit irrigation, you’re going to see your crop not yielding as much as in the past,” says David Doll, a pomologist and noted almond expert with UC Cooperative Extension in Merced County.

In fact, reducing irrigation produces a double-whammy for growers: A smaller yield this season and the next year as well.

Almond trees are considered drought tolerance.

Doll says trees will adjust to and become stable if the water drop-off isn’t too steep. “What we’re seeing is if a tree is maintained at an irrigation rate of 70 to 90 percent of normal it will stabilize at that amount of water application.” Of course, that depends if a grower has enough water available to even maintain irrigation at a 70-90 percent level.

Dry times are causing other worries, Doll adds.

“What is becoming more of a concern in these times of drought is the accumulation of salt within the root zone. We can get an impact from salinity due to the increase in salt load, which makes the tree work harder. If you apply the same amount of water you may not see the same response from the tree.”

This means trees with a high amount of root zone salinity are thirstier and giving them the same amount of water won’t be enough to produce the same results as in the past at harvest time. UC officials describe the root zone salinity threat as a “sleeping dragon.”

Root zone salinity: A 'sleeping dragon' in almonds.

In the meantime, another dry winter and spring in 2015 has sped up almond development this season and Doll and other experts expect harvest time to arrive a few weeks earlier than usual. “We are having thicker hulls and smaller kernel size.”

On a positive note, Doll credits almond growers with becoming more in tune with their irrigation practices, working on ways to maximize their water distribution systems and putting in things such as pressure regulators and installing reservoirs.

 “I’m seeing a lot of innovation going on in orchards to make more efficient use of water,” Doll says. He recommends growers go online and download the UC ANR Publication No. 8515 titled“Drought Management for California Almonds.”