Red, white, and green
Wine grape tour highlights sustainable practices.
WAWGG members walk across green manure cover crops at the crest of the Seven Hills project near Milton-Freewater, Oregon. The block planted down the hill includes a cover crop of Sudan grass.
Washington wine grape growers have long been drenched in reds and whites, but the industry is increasingly adding a third color to the palette—green. From green manure to compost teas, a growing number of grape growers in the state are testing organic techniques in their vineyards.
More than 70 growers and winemakers took a closer look at organic approaches to pest and disease management when they toured the Walla Walla Valley with the Washington Association of Wine Grape Growers annual summer tour. WAWGG Executive Director Vicky Scharlau said the group chose the theme because it's an important part of the larger picture of sustainability.
The first stop on the tour was Rick Trumbull's compost tea production facility. Trumbull operates Sustainable Soil Solutions, Inc., and consults with growers about organic nutrient programs. He produces compost tea as a foliar spray to combat plant disease, and as an additive to soils to rebuild the level of biological organisms. That biology, Trumbull says, provides the nutrients the plants need while preventing undesirable organisms from establishing a foothold.
"I believe it's all about nutrition and the mineral density of the plants," he said. Much of the land in the valley has been planted to wheat for decades, depleting the soil of calcium and phosphorus. Compost helps restore those essential nutrients by supplying earthworms with the food they need. The worms' castings and slime, in turn, provide the nutrition for the biological organisms that feed the plants, and, at the same time, protect them from diseases and pests like powdery mildew and thrips. "When the mineral density of the plant measures at around 10° Brix, then you have complete proteins," he said. Because insects can't digest complete proteins, the plants are naturally resistant to insects.
When used as a foliar spray to combat powdery mildew, compost tea is applied more often than a chemical spray, sometimes requiring almost weekly passes through the vineyard, which can add to its cost. But, sustainable agriculture should be assessed on a long-term basis, Trumbull said. "If you plant a piece of land with wheat for 40 or 50 years, you're going to have to pony up on the nutrients in the soil sometime."
In fact, Scharlau said, that kind of long-term thinking about sustainability has been one of the main focuses of WAWGG. The group's Vinewise program, a comprehensive tutorial on grape production, includes components on topics like financial management, soil management, marketing and pest management, all designed to help growers think about the likelihood that their land will still be in production a hundred years from now.
Organic, Scharlau pointed out, doesn't always mean sustainable. A big part of sustainability focuses on economics and profitability, and the WAWGG members on the tour returned throughout the day to questions about the cost of organics. WAWGG's Web site includes a calculator estimating production costs of Northwest grapes. For established vineyards, it shows an average cost per acre of $3,621 for conventional farming. That jumps to $4,331 per acre for organic farming.
Still, for growers with enough time and money, the benefits are significant, according to Chris Banek. He manages the Seven Hills Project in Milton-Freewater, Oregon, where he is rebuilding the soils using green manure crops like Austrian peas, triticale, Sudan grass, mustard, and oats. Planted over two or three years before grapevines go in, and later as cover crops, those plants serve several purposes. First, they hold the soil in place, and, later, after being disked back into the ground, they return nutrients to the soil. Also, Sudan grass can serve a windbreak, protecting young grapevines.
Ideally, Banek likes to see the land treated with green manures for two or three years before planting a vineyard, but time and budget pressures often won't allow that. He estimated that planting green manure crops adds another $90 per acre to the cost of establishing a vineyard. Still, Banek said the cost also carries a return. "We have improved the quality of the soil, and I believe the wine grapes are getting better as well."
Other vineyards on the tour included Figgins Estate Vineyard in the Blue Mountain foothills, where Chris Figgins explained some of the sustainable techniques he adopted. Merlot vines all sprout a burial cane near the ground, which are covered in insulating earth every winter to protect them from freezes. Spring cover crops like crimson clover help contain erosion while providing a good pollen source. In addition, Figgins uses green manures, compost, and compost teas to rebuild soil nutrients, an approach he said has shown positive results. "In the blocks with the highest microbial concentrations, there's a direct correlation to high aromatics in the wine," he said. "With compost and compost teas, those numbers are really taking off. I think we're seeing better pest and disease resistance. And we're definitely seeing a difference in weed species."
Figgins has included in every block a biodynamic row of wildflowers, and plantings of perennials like lavender and wild roses, creating a home for beneficial insects. "You get one or two pictures of the biodynamic row when it's in bloom in a wine magazine, and it's paid for," he said.
At nearby Yellow Bird Vineyard, Appellation Management Group General Manager Ken Hart stood under towering vines in just their second leaf and pointed to irrigation lines connected to nothing. The 16-acre vineyard, planted to seven different varietals, is the first dryland commercial vineyard in Walla Walla. The drip tubes, Hart explained, were installed as a sort of safety net. In 2007, the plants were a little smaller than those in a newly planted block he pointed out nearby, where young vines sprouted near the ground. One year later, without irrigation, the vines at Yellow Bird showed enough vigor to prove the drip lines aren't needed. The area averages 20 inches of annual rainfall. Seventeen inches fell in 2006, and 15 inches in 2007. Hart said the soils have been treated with a compost blend that includes mineral rock, logs, hay and grass, sawdust, and yard dust, with clay added.
On the valley floor at the 8.5-acre Waliser Vineyard, Tom Waliser discussed his efforts to control powdery mildew with biologically based products. In 2006, he administered products including the nutrient supplement Cal-Sup, compost tea, Micro 108 (Streptomyces lydicus), and saponin weekly from May through July. He cut that schedule back somewhat in 2007, averaging an application once every ten days. He saw no mildew last year, he said, but another fungal disease, Phomopsis, made its way into the vineyard. Waliser said he treated that with Pristine (F500 and boscalid) and Kumulus (sulfur). This year, Waliser has returned to traditional chemical sprays, but he continues to look at soft, safe methods.