Vineyards brace for effects of drought, warm weather

Napa Valley Grapegrowers say crop could be limited in 2014
2014-01-28T13:31:00Z 2014-02-05T11:58:13Z Vineyards brace for effects of drought, warm weatherSASHA PAULSEN Napa Valley Register
January 28, 2014 1:31 pm  • 

January’s unseasonably warm weather is waking up dormant grapevines weeks earlier than usual, adding one more challenge for Napa Valley grapegrowers in 2014 who are coping with drought.

With rainfall at record lows and budbreak beginning throughout the valley in January rather than late February or March, the Napa Valley Grapegrowers hosted a news conference Tuesday to discuss what lies ahead for their more than 670 members.

“This won’t be a year to take a long vacation,” said Jennifer Putnam, executive director of the Grapegrowers. Putnam, along with Domenick Bianco, vineyard manager for Renteria Vineyards, and Hal Huffsmith, vineyard manager for Trinchero Estates, answered questions during an hour-long meeting that was streamed lived over the Internet, inspiring tweeted questions from around the country.

“We’re coming off a dry base in 2013 — the driest year on record,” Putnam said, referring to rainfall measured since July. Napa County typically has received between 15 and 20 inches by now, but rainfall since July adds up to just 2.5 inches on the valley floor, she said.

“The last time we saw similar conditions was 1976-77,” Putnam said.

Officials noted that Napa County agriculture was not alone in facing water shortages. Gov. Jerry Brown declared a drought emergency for all of California on Jan. 17.

Although showers have been forecast for this week, Putnam said, “The operative word is ‘showers.’ We want rain. If we could get eight inches, we’d be set.”

In lieu of rain, Putnam said the grapegrowers are developing contingency plans and will draw on “extensive resources” and information exchanges “that help everyone.”

Huffsmith said extensive monitoring of groundwater has been underway, but “groundwater does not make up for lack of rain. Groundwater is a crutch.”

The growers could be looking at a greatly reduced yield this year, he said. “The amount of water available will determine yield.”

Although farmers are fond of saying that “every year is the same — different,” in a typical January the focus would be on pruning as cover crops like mustard fill in the rows between dormant vines. Pruning usually goes on through February.

This year, without rain, there are few cover crops, which provide erosion control, add nutrients to the soil and encourage helpful insects.

With reports of budbreak in chardonnay vines already underway in regions like Stags Leap and Carneros, “we may face a compacted pruning season,” Bianco said, and this could be further impacted by labor shortages to get the work done in a shortened time.

The frost season, which typically runs through April, presents another problem for early budbreak. Many growers depend on wind machines, which bring in higher, warmer air and can keep temperatures from dropping below 32 degrees near the vines, but other growers use water to form a protective ice coating over fragile news buds and shoots.

Growers who depend on water for frost protection could face problems if they don’t have water in wells or reservoirs. Huffsmith said some growers are allowed to draw water from the Napa River for frost protection but this year the river is so low that may not be permitted.

Some growers also use water to cool down vineyards during heat spikes in the summer, Huffsmith said.

The situation varies from vineyard to vineyard throughout the valley, said Bianco, who farms 1,900 acres in the county for Renteria. He described one vineyard on the valley floor that has enough water to presently use overhead sprinklers to “pretend like it’s raining,” while another vineyard in Calistoga has no groundwater and no water in its reservoir.

Huffsmith, who oversees 9,500 acres of vineyards in 10 counties, for Trinchero and Sutter Home, said Napa County has an especially strong aquifer, an underground layer of water-bearing materials from which groundwater can be extracted, but no one is sure the extent to which it can be relied upon, especially if the drought extends into 2015.

As the vines begin to grow, Huffsmith said, “We’re going to reduce shoots, (which) might reduce cropload.” This includes removing shoots that growers might otherwise have left to grow in the following year, but this will “allow vines to focus their energy on the ripening fruit.”

Special care will be given to management of the canopy — the vines’ leaves — which controls exposure to the sun but also draws on the vines’ limited water resources. “We’ll make sure we don’t have excessive canopy,” Huffsmith said.

“More than ever we’ll be relying on technology to determine when to water,” Bianco said. Current tools available for growers can allow them to monitor individual vines’ need for water. “Timing is key to reducing waste,” he said.

Bianco also noted that another potential danger to vines in a dry year may be pests. “We expect to see more mites and leafhoppers,” he said. “Insects know when a vine is stressed and will attack.”

“There’s much we don’t know and much we will learn (this year),” Huffsmith said. While it might require a miracle to bring adequate water supplies up, “a miracle would be welcome,” Huffsmith said.

“Farmers are fairly adaptive and we’re optimistic,” he said. “I’m not cutting my wrists yet.”

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