Sara Natividad
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The sun is bright, the air is dry and Cal Poly’s vineyards are thirsty.
To help quench the crops’ thirst, the wine and viticulture program irrigates the fields with a drip-irrigation system — but after one of San Luis Obispo County’s driest years in 2013, and only one day of rain in 2014, an irrigation system is simply not enough.
Cal Poly’s wine and viticulture program has practiced water conservation techniques prior to the dry winter, but the drought amplified their approach. The vineyards are pouring over every sprayer head in the drip system and students are manually scrubbing barrels in the wine cellar.
But even with these conservation techniques, the crops still need rain.
“There is nothing like rain — it falls everywhere, not just through drips,” vineyard manager Craig Macmillan said. “And it comes gently over a long period of time. We can do things with irrigation, but we can’t actually get all the benefits and get rid of the salt like we need. It’s not as effective.”
During dry seasons, salt builds up in the vines and dehydrates them. An irrigation system does not distribute water effectively enough to prevent the salt build-up.
“It is the topic that everyone is talking about,” Cal Poly’s vineyard manager Craig Macmillan said. “Basically everyone is stressed because it is bad now, and we don’t know how bad it’s going to be.”
Macmillan hopes a decent amount of rain will flood the fields and save this season’s crops, but is frustrated by the unpredictable situation.
“It is the topic that everyone is talking about,” he said. “Basically everyone is stressed because it is bad now, and we don’t know how bad it’s going to be.”
Cal Poly’s wine and viticulture department has yet to meet as a whole to discuss possible changes in their growing methods, Macmillan said. One possible change on the horizon is to prune the vines so the field has fewer crops with smaller yields, but it is too early to predict the impact the drought will have on the quality or quantity of the crops.
Since controlling rain is not an option, the viticulture program is focusing on what they do have power over: the efficiency of irrigated water usage.
Cal Poly has increased their moisture-monitoring efforts, which examine when water is depleted from the soil and help decide when and how much water they need to apply. Macmillan said this allows them to water the crops less frequently.
They are also working to improve irrigation efficiency. Cal Poly students in the Drip/Micro Irrigation (BRAE 438) course examined the distribution uniformity of the drip system last week. The goal of distribution uniformity is to have water evenly distributed throughout the crops, said Daniel Howes, the systems professor in bioresource and agricultural engineering who teaches the class.
When crops have uneven distribution, more water must be distributed to the entire crop so the areas with low distribution receive enough water to grow. As a consequence, excess water is wasted in areas with high distribution.
The class evaluates the irrigation from 0 to 1, with 1 being perfect. The last time the class inspected Cal Poly’s vineyards was three years ago and the score was a 0.9, Howes said. He expects the current irrigation system to perform at a similar caliber.
Cal Poly has also been working on a long-term project to improve the soil so it is more “spongy” and absorbs more water instead of allowing it to drip off. They have been working on this for approximately five years, Macmillan said, and it should be a 10-year commitment.
These programs are not new to Cal Poly’s wine and viticulture program, but they have had a renewed approach since the drought, Macmillan said.
In addition to the conservation techniques used in the field, the wine cellars at Cal Poly implement water-efficiency strategies into wine-making.
Wine and viticulture lecturer Matt Brain was hired in 2011 as Cal Poly’s cellar master. Part of the reason he was chosen was because of his emphasis on water conservation and production knowledge, he said.
Since then, Cal Poly’s winery has used a variety of water-saving techniques for cleaning and sanitation, which are the main uses of water in the winery, Brain said.
For most of their sanitation, they mix water with light chemical bases such as light acid and citric acid. Diluted chemical mixtures use less water than using water alone, he said.
Instead of using constant high-pressure hoses, they physically scrub barrels without water pressure, then quickly rinse the barrels after.
Though these techniques take “more elbow grease and manual work,” they use less water.
Spreading awareness that water is a diminishing resource has to be a priority, Brain said. Young winemakers need to bring this philosophy to the industry and pay more attention to water use, he said.
“It’s starting to become a real limiting factor in the industry,” Brain said. “It’s gone from something that has gone for granted, to being scarce, to becoming a really really big concern in our industry.”
San Luis Obispo isn’t the only county affected by the dry weather. The U.S. Department of Agriculture declared San Luis Obispo one of 27 California counties to be a natural disaster area.
One positive aspect Brain hopes will come out of this drought is a nationwide shift in the wine industry toward water conservation, which he considers a “conscious level of winemaking.”
“This is a level of winemaking that I hope our students take with them,” Brain said. “Making good wine, but also trying to balance being conscientious of water.”