'Rolling stumping' could be in future for avocado trees


Issue Date: April 14, 2010
Kate Campbell

"We're just trying to survive," said Chris Ambuul, a San Diego County avocado grower and grove manager. "That's the future, barely hanging on and hoping something happens to improve the water supply situation five to 10 years out."

In water-short California, survival mode is the new normal for many farmers, he said.

Facing 30 percent water cutbacks two years ago, many avocado farmers cut back their trees—a process known as "stumping"—to reduce their groves' water needs. Now, the trees are starting to come back, but the water supply isn't.


Avocado trees, cut back to stumps two years ago to save water, are now returning to production in San Diego County and farmers such as Chris Ambuul, above, study the trees very closely. They're looking for signs of vigor and early fruit, as well as leaf burn from salts and lack of water.

Ambuul said many avocado growers in his area will likely have to practice rolling stumpings—stumping groups of trees in phases—to keep groves alive, while cutting water use and still managing to pay escalating water bills. He has stumped about 75 acres of the nearly 450 acres of avocados he farms. Without investments in new equipment and alternative water sourcing, the number of acres pulled from production would have been closer to 450 of the total 1,700 acres he manages.

"It cost the growers I work with more than $1 million to retrofit 350 acres of avocados with the latest irrigation technology," he said.

Avocados require about 3 acre-feet to 4 acre-feet of water. Stumping the trees brings water demand down to zero, at least in the first year, Ambuul said. After that, the trees begin to require more water as they come back into fruit production.

The stumpings began after the Metropolitan Water District of Southern California imposed 30 percent cuts in 2008, for water available through its agricultural discount program.


Short water supplies forced many Southern California avocado farmers to cut trees down to stumps in 2008.

Under the program, participating farmers save about $100 an acre-foot of water in exchange for agreeing to cutbacks of as much as 30 percent when MWD water supplies run low. The amount of the discount is being reduced each year, with phase-out scheduled within five years. Non-discount water now sells for more than $1,000 an acre-foot through MWD-member water agencies.

To meet the cutback requirement for discount water deliveries, many avocado growers stumped trees to reduce water use. Experts say about 4,700 acres of avocados in San Diego County were stumped. After being cut down, the trees revitalize within a few years and return to producing fruit. That's already beginning to happen in some groves.

"I stumped in '08 and now some of the trees have fruit on them," said Russ Hatfield, who grows avocados in San Diego County. "But not all the trees came back. I lost about 2,200 trees to wildfire and then I stumped 1,700. Out of the stumped trees, about 65 percent have come back. With the wet winter, those trees are doing very well."


San Diego County avocado farmer Chris Ambuul, above, said the practice reduces the trees' water needs to near zero at first, but then demand returns as the trees regenerate.

But Hatfield said he's cautious about replanting and making a commitment to a permanent crop when water availability and prices are uncertain. He's surviving this year, he said, on fruit that has come back on the stumped trees, but doesn't know how much longer he can keep going.

"Since '07, I've been carrying everything out of my pocket," Hatfield said. "I can't rely on my reserves forever. At some point, I'm going to have to break even or get out of the business. I'm optimistic, but the water rate increases are killing us."

Many farmers, including Hatfield and Ambuul, have tried to drill wells in search of groundwater to supplement what they're buying from their local water district, but oftentimes they come up dry. Hatfield said he spent $13,500 to drill a 900-foot well and didn't find a drop. Another company offered to drill deeper at a different site for $50,000 but couldn't guarantee any water. Hatfield said he won't be drilling any more wells soon, especially now that income from his avocados has been cut.

He said that in 2009, his irrigation costs were $32,000 and he earned $25,000 from the sale of his fruit.

"Mind you, that doesn't include the cost of labor, taxes and supplies," he said. "It all adds up."

Tom Bellamore, president and CEO of the California Avocado Commission, said farmers in the MWD interim agricultural water program were able to reduce demand by well more than 30 percent last year.

"But this saving is at the expense of farmers' operations," Bellamore said. "The growers performed on their agreement with MWD, but they're hurting."

An average rainfall year in the Southland has helped growers, he said, but adequate water deliveries in coming months are in doubt.

"Water for San Diego comes from the State Water Project, which currently says it will deliver 20 percent of contract amount to water agencies, including MWD. The rest will come from the Colorado River, which continues to suffer from a long-standing drought," Bellamore said. "That's why our growers will continue to face cuts in water deliveries."

One benefit of adequate rainfall, Bellamore said, is that the salt buildup around the roots of the avocado trees has been leached away. But with lower water deliveries and a higher proportion of water coming from the salty Colorado River, the problem of salt buildup will continue.

The dilemma for growers now is that stumped trees are coming back into production, but the region's water supply continues to be unreliable, of poor quality and too expensive.

When asked, "Now what?" Bellamore said, "That's exactly the concern the commission's board has been talking about. In the past, when growers stumped it would be for good cultural practices."

And, he said, farmers stumped trees with the expectation that the trees would return to full production in three to four years.

"Now, we've seen through our assessment of the situation that groves have been abandoned and trees are being permanently removed," he said. "Russ Hatfield is a perfect example of growers who are at a crossroad. He stumped because he had to, the water supply picture hasn't improved, and now what does he do?"

He said the commission expects that some growers will continue for a few more years, but may not be able to hold out until the water supply situation improves.

"The general feeling by our board is that a high percentage of the 4,700 acres of trees that were stumped won't return to production," Bellamore said. "Right now, stumped acres account for more than 17 percent of total avocado acres in San Diego County. That's quite a bit."

San Diego County Farm Bureau Executive Director Eric Larson noted that MWD is ending its discount program for agriculture, "and escalating water prices are a big deal. What's happening is some growers—mostly the smaller ones—they're just turning off their water to their trees."

He said local water districts are seeing drops in overall water sales to farmers in the range of 40 percent.

"That means, in addition to the mandatory cuts, it's obvious some folks just aren't buying water anymore," he said.

In western Riverside County, which also has considerable avocado and citrus acreage, the impact of the discount water program phase-out means higher and higher water bills, said Steve Pastor, Riverside County Farm Bureau executive director.

"Higher water prices mean just one more hurdle to jump. We don't have hard numbers right now on what this change will mean in our county or across Southern California," he said, "but the impact on farmers isn't good."

(Kate Campbell is an assistant editor of Ag Alert. She may be contacted at kcampbell@cfbf.com.)

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.