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Winegrape grower nourishes soil to combat drought

Issue Date: April 13, 2022
By John Beck
Paul Bernier, working in his Sonoma County vineyard, embraced “dry farming” long ago. He shuns traditional irrigation lines and instead works to retain moisture in the soil with cover crops and compost, including ingredients from duck manure to crushed oyster shells. Studies from University of California, Davis, researchers suggest vines can use 50% less water with little impact on quality.
Photo/John Beck
Paul Bernier says he manages the soil and landscape of his vineyard with minimal water use.
Photo/John Beck
Paul Bernier
Photo/John Beck

When Paul Bernier learned to "dry farm" grapes from old Italian growers in the early 1970s, the idea was simple: "In a climate where it rains in the winter and it's dry in the summer, you had to figure out a way to retain the moisture in the soil," he said.

Bernier embraced that philosophy at a time when deals were made with handshakes, which was well before drip irrigation lines were strung across Sonoma County's Dry Creek Valley vineyard region.

"They call it 'dry farming' now, but they used to just call it farming," recalled Bernier.

Over the past five decades, Bernier has used less water than many grape growers use in a year. Granted, his operation is relatively small scale. Aside from his 1.5-acre family vineyard, he farms 35 acres of mostly head-trained zinfandel, paying each landowner around a quarter of the yield, while selling his grapes to Sbragia, Dutcher Crossing, Nalle and Peterson wineries. None of the vineyards use any irrigation lines.

"I'm basically building up the nutrients in the soil because the dirt is a sponge for the rain and the moisture that comes in the wintertime," he said, explaining his no-irrigation cultivation. "All that organic matter in the soil makes more of a sponge, and more of sponge means bigger plants and more crop."

Now, as the third year of a severe drought bears down on California farmers, and the dry-farming approach of Bernier and others is tested to its limits, it raises a very relevant question: Could North Coast growers in Sonoma, Napa, Lake and Mendocino counties get by with watering less during the drought?

Last September, a University of California, Davis, study showed that giving vines 50% less water than they typically demand didn't affect yield, taste, color or sugar content.

"The idea of the trial was, it's so hot and we're having these heat waves; do we need to increase the amount of water that we apply?" said Kaan Kurtural, a UC Davis professor of viticulture and enology. The results of the study he co-authored showed that may not necessarily be the case.

Bernier is a believer. To retain moisture, he cultivates his soil by turning over a healthy cover crop of native vetch and mustard, along with planted legumes. He layers that with various composts he makes from grape pomace and duck and horse manure. That helps hold moisture in the soil well past the rainy season and into the annual harvest. He also occasionally enriches the soil with crushed oyster shells he sources from Suisun City.

Last June, in the dog days of the drought, he texted a photo of moist soil only 6 to 8 inches below the surface, showing his vineyard was still holding moisture.

But he is not one to brag or to try to convert others; Bernier's journey has been one of necessity. He had to farm this way because most of the neglected vineyards he inherited and nursed back to life had no wells or scarce water resources.

He's not the only one. There are a few other dry farmers in Sonoma County. Across the Mayacmas Mountains, there's a cabernet sauvignon test plot at the UC Davis research vineyard in Oakville that hasn't been watered in 29 years and still produces 6.5 tons to the acre.

The most recent UC Davis study took place in 2019 in a Napa cabernet sauvignon vineyard. It was just before the current drought but when heat waves, especially late-summer ones, were prevalent.

Kurtural said the findings are promising for water conservation.

"Looking at cabernet, which grows all over California, we found you can get by with 50% of plant demand and still get a very handsome yield with top-notch quality, and with soil microbes still living in the vineyard as well," he said.

It's nothing Bernier didn't already know. In the late '70s and '80s, when drip irrigation recast the vineyard landscape and dry farming was forgotten—almost like a lost art—he could see how the daily drip affected vines.

"When you treat a vine with irrigation, you give it the water it needs, and it doesn't need to expend energy going out looking for food," he said. "So its root system is not out utilizing all the ground. It's just hanging around where it's wet, where the dripper is. It's like an alcoholic at 6 a.m. waiting for the bar to open to get his shot before he goes to work."

Over the years, other grape growers and wineries have taken notice and adapted based on Bernier's methods. In 2017, Bernier led a dry-farming workshop sponsored by the California Alliance with Family Farmers, with several dozen growers in attendance.

"It just makes sense," says Fred Peterson, owner of Peterson Winery, who started buying grapes from Bernier in the mid-1990s. Seeing the benefits, he started composting regularly in his own vineyards and is now conducting a dry-farming trial in a vineyard on Bradford Mountain. "It's that idea of 'healthy soil makes for healthy vines,'" he said.

Applying annual compost additions, "really made a difference," Peterson said. "It costs around $350 an acre to put on 5 tons per acre. But nowadays, with what fertilizer is going for, that's actually a deal."

Peterson said most growers don't dry farm because typically more water equals more tonnage, and that equals more money. But more tonnage doesn't always equate to better quality grapes.

"Just having bigger yields doesn't mean your quality is gone," Peterson said. "But at some point, it's diminishing returns. At some point, you're growing bags of water. You're just pumping them full of water and waiting for the sugars to come up."

Last year, Bernier's average yield of 3 to 4 tons to the acre was cut in half because of the drought. As the bone-dry climate continues, he's now thinking about laying temporary irrigation lines in his vineyards in July for a flash watering to sustain them into the harvest.

At 73, Bernier is gradually handing the reigns over to his son, Zureal, who grew up farming side by side with both of his parents. Paul's wife, Yael, runs Bernier Farms in Geyersville, growing organic vegetables and a cult-favorite garlic prized by local restaurants.

This summer, Paul and Yael are planning a long-awaited, cross-country road trip in their VW bus—that is, if they can step away from the farm long enough to "semi-retire" for a few months.

He has this advice for his son as he takes over the family farm in the interim:

"Water if you have to," he said. "It's not a religion. We've got to make a living, too."

(John Beck is a reporter and documentary filmmaker based in Benicia. He may be contacted at john@beckmediaproductions.com.)

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




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