Proper vineyard irrigation can help growers save money, improve quality and yields and promotes sustainability. The question is what is the best way to achieve optimum irrigation? This question and others about providing water for vines that will be addressed at the Irrigation Management Workshop, April 8, in Paso Robles, Calif.

This will be the second annual one-day workshop focusing on practical irrigation management for growers, managers and consultants on the Central Coast. The program was developed by soil-plant-water relations specialist, Lowell J. Zelinski and is being hosted by his company, Precision Ag, Inc.

There will also be a supplier showcase and soil moisture monitoring equipment demonstrations.

“I enjoy teaching and the opportunity to share with others what I have learned through my experience and education,” Zelinski says. “I also believe that in order for the Central Coast to become a world-class wine producing region, continuing education and good agronomic practices are critical. There are other educational opportunities in viticulture; however, most of them do not focus on practices for the Central Coast, nor are they offered here.”

Two of the latest technologies in irrigation scheduling that will be addressed are the leaf Porometer — a new hand-held, easy-to-use tool that records plant water status by measuring stomatal conductance in leaves — and the MPS-1, a new matric (soil water) potential sensor. Both products were developed by Decagon Devices.

Mark Greenspan of Napa Valley, Calif., will talk about the use of the leaf Porometer in vineyard irrigation scheduling. Lauren Bissell, a product manager from Decagon Devices is going to discuss how to use soil water potential to schedule vineyard irrigations and introduce the matric potential sensor.

“The two most important questions to answer when scheduling irrigations is ‘when’ and ‘how much,’” Zelinski explained. “Soil moisture sensors do a great job at telling you how much but not when. For someone to get the most out of their irrigations, they really should know both.”

The MPS-1 matric potential sensor was developed by soil scientist Galen Campbell, a professor at Washington State University and the lead scientist behind the soil moisture monitoring technology developed by Decagon Devices.

Water potential sensors measure how strongly the soil is holding onto water or how hard the plants have to work to take up the water from the soil. According to Zelinski, the MPS-1 can measure a greater range of soil water potential than other water potential sensors on the market. That said, Zelinski believes that the leaf Porometer is the best tool for answering the “when” question.

“When considering when to irrigate, it makes the most sense to ask the plant when it needs water rather than infer the plant water status from the soil-water status. They are both excellent tools and there are pros and cons to both,” Zelinski said.

The pros and cons of these two pieces of equipment, as well as other soil moisture products on the market will be one of the features of the workshop. Current workshop equipment sponsors include AdCon, Automata, Decagon Devices, Eko/Crossbow and Irrometer Co. The meeting is also being sponsored by the Central Coast Vineyard Team (CCVT) and the Independent Grape Growers of Paso Robles (IGGPRA).

Attendees will be given a guide to compare the benefits and features of the systems, and then learn why they should use them and how. Zelinski will cover basic soil-plant-water relations and irrigation scheduling methods. Cal Poly San Luis Obispo soils professor, Tom Rice will discuss local soils; Steve Gratten, a soil-water specialist from the University of California, Davis, will address irrigation water quality; University of California Cooperative Service farm advisor for San Luis Obispo County, Mark Battany will teach how to determine crop coefficients, and Paul Sorensen, a principal hydro geologist from Fugro will give an update on the Paso Robles groundwater basin.

Seating is limited and the early registration deadline is April 1. CCVT and IGGPRA members receive a $10 registration discount. For more information or to register, please visit or call (805) 239-8200. Discounted rooms are available at the Paso Robles Marriott by mentioning Precision Ag, Inc.