New water conservation project to help local farmers

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ByDavid Louie KGO logo
Wednesday, May 14, 2014
Tomato plant at Sherrie's Farms in Gilroy.
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GILROY, Calif. (KGO) -- The extreme heat wave is creating a dilemma for fruit and vegetable growers. The drought has put pressure on them to conserve water. A new water conservation project is now underway that's employing high-tech methods to find the best balance to water plants but not hurt the quality.

Sherrie's Farm in Gilroy, like many in South Santa Clara County, has switched to drip irrigation to save water. But growers now have a new tool to add to intuition and years of experience to know when to adjust water usage.

Last year Sherrie's Farm, a six acre organic operation, used one acre foot of water. That's equivalent to one or two households for a year. Given the drought, the goal is to use even less, perhaps by as much as 10 to 15 percent.

And that's why Michael Johnson with California Horticulture Services was in the field Tuesday starting a water use audit.

"They depend on the water," said Johnson. "They want to take good care of the land and the water because that's their livelihood."

He installed soil and moisture sensors, called tensiometers. He and his colleague are also checked for leaks and clogged emitters in the drip irrigation system. Seventeen area growers are participating. Data will be collected to help Mike and Sherrie Kennedy determine when to adjust the flow of water and by how much.

It will help them diagnose what to do when plants are stressed by too little or too much water. The data will also supplement their intuitive knowledge.

"If we found that the plants weren't looking, growing as strong, then we knew something was wrong," Sherrie said. "And usually we'd look for the water or we'd look to make sure there wasn't an invasive pest."

The first data will be available in a week and then accessible on demand.

"Having access to the data immediately can help you make decisions right away as opposed to waiting until the end of the season and making changes the next year," Johnson said.

This week's heat wave will require more water because the seedlings haven't developed leaves to shade the soil and retard evaporation.

"When plants are little the roots aren't deep yet," said Mike. "So we've got to keep the top moist but at the same time drive some water down deeper so the roots want to reach."

Water conservation is a delicate balancing act as stressing a plant with too little water can impact the flavor and quality of the tomatoes.