Vineyard Irrigation: Wet Your Plants with Efficiency & Precision

By: Gerald Dlubala

The importance of water and its management for grapevine quality and yield cannot be overstated,” said Randy Heinzen, president of Vineyard Professional Services in Paso Robles, California.

  “When it comes to irrigation,” said Heinzen, “vineyards depend on drip irrigation for the most part. Sprinklers are great at spreading water across the entire acreage, but applications by sprinklers in-season can increase the potential for disease in the canopy. I haven’t worked on a furrow irrigation system (which diverts naturally accumulating water into channels that run into or along each side of the vineyard rows) here on the Central Coast since 2011. Choices will always differ by region, and some vineyards successfully utilize dual systems that combine drip and overhead systems or drip and under vine micro-sprinklers. Grapevines are fairly drought tolerant, so they readily adapt to receiving drip irrigation at several points near the trunk.”

  Heinzen said that most vineyard managers prefer drip irrigation systems because of the ability to provide a directed and constant volume to each plant. Another advantage of utilizing a drip system is the ability to fertigate and apply chemicals directly and precisely to each vine when needed.

  “The type and amount of scheduling for those needs varies based on system ability, soil dynamics, the winegrower’s goals, and seasonal weather events and conditions,” said Heinzen. “At the most basic level, irrigation is applied at some fraction of the grapevine’s water use. Other variables include the time in the growing season and the grapevine’s age, root system, soil interaction level and general overall health. And the more active the leaf area is that is photosynthesizing, the greater the water use is going to be by the plant, which in turn requires a greater need for water replenishment.”

  Heinzen told The Grapevine Magazine that the cost of installing a drip system depends on the volume of water available for irrigation and the vineyard spacing, layout and design. The cost of mate

rial and installation of a drip system’s sub mains through to the above-ground infrastructure can be between $3,000 and $6,000 per acre, comparable to installing a quality sprinkler system.

  “Most vineyards track irrigation through flow meters and in-field pressure systems in drip hoses,” said Heinzen. “But, while digital tracking removes most human errors caused by erroneous note-taking and transcription of numbers, technology is not always reliable, and data gaps can occur. A novel approach to monitoring irrigation uses satellite imagery to estimate actual evapotranspiration and deduce the correlating irrigation needs. In terms of field operations, there are several automated systems available for remote pump and valve control, but the same caveat about reliability applies to agricultural field technology as well.”

  “With that in mind, a vineyard owner’s most important question for the irrigation system installer concerns the warranty. For most vineyard owners, the irrigation systems are installed by third-party contractors, with the majority of their work buried underground. The most professional and experienced contractors give the best warranties because they are good at their craft. In my experience, paying more for that professional design and installation upfront eventually saves money in the long run due to the potential of more costly and untimely field repairs and maintenance after installation. Further, vineyard owners should educate themselves on how the system runs, how to use it, and how to handle and make minor repairs themselves. Disruptions in the availability of needed water impact current and future crops, so as the vineyard manager, you should know the location of the underground pipes, how the controllers and filters operate and what pressures your system is designed to maintain for optimal performance. A good relationship with your contractor is critical to your farming success.”

Water Efficiency Is Key: Noble Vineyard Management Services

  “Water efficiency is key when choosing irrigation systems,” said Tyler Rodrigue, CEO of Noble Vineyard Services, a full-service, vineyard-to-winery service operating on California’s North Coast. “The grape-growing industry has been forward-thinking for decades regarding efficient water applications and measuring cost benefits and needs to ensure that our water resources are put to their highest, most beneficial use. We use drip irrigation systems in spring, summer and fall to irrigate the vines. Then, if we’re not getting normal rains, sprinklers are used during late fall, winter and early spring to simulate normal rain conditions and provide a good soil profile.”

  Like Heinzen, Rodrigue said that drip irrigation is the preferred choice because of its efficiency. “It’s important to ensure that vineyards are adequately irrigated through the seasons, including pre-budbreak, during the growing season and then through the harvest into post-harvest. Rainfall received during our rainy season naturally influences our irrigation schedules. As a rule of thumb, we like to have an approximately one-acre foot of water available for irrigation during the growing season. We use remotely controlled, automated irrigation systems that provide leak detection and track the amount of water allocated during the irrigation session, the vine water capacity and critical soil moisture levels.”

  Rodrigue recommends that vineyard owners perform quality research before choosing a system. Always check with other growers who use similar irrigation systems to validate capabilities, user-friendliness and return-on-investment (ROI). Finally, choose a distributor that offers serviceability and critical support when you need it. Drip, sprinkler and micro-sprinkler systems can all seem expensive because of the infrastructure necessary for proper performance, including PVC pipe, fittings, sprinkler heads, drip tubes, motors and pumps. Still, when appropriately scaled, the ROI ranges in the three-to-five-year range.

Precision Irrigation in Stages: William Chris Wine Company

  Tate Gregory is the Vineyard Manager for William Chris Wine Company, located in Hye, Texas. He told The Grapevine Magazine that it’s close to, if not impossible, to establish a vineyard in Texas without some form of irrigation system in place. Like the others, he prefers drip irrigation systems, the choice method in Texas, for all the wineries he oversees.

  “Drip irrigation allows for more precision in your watering and chemical injection needs,” said Gregory. “A drip system is probably one of the more expensive options when starting, but the ability to granularly control your water and nutrient applications is well worth the upfront cost. The emitters on the drip system ensure that the proper amount of water needed is dispensed and directed towards the root zone of the vines underneath the row. Additionally, those emitters allow the desired amount of water you want at each emitter, reducing water waste by not irrigating unnecessary areas. Sprinkler systems will direct a lot of water to your vineyard all at once, but sprinklers can’t precisely deliver water to a target. On top of that, you can end up with mildew or other fungal issues that arise from having a moist canopy during your growing season. I have seen sprinklers used in vineyards as a form of frost protection, but here in Texas, we use fans.”

  “The watering comes in stages for our vineyards, unless you’re in a drought like we are currently experiencing, when we irrigate more frequently just to maintain vine health,” said Gregory. “Here in Texas, we usually get in-season rains that supplement our irrigation plan, which depends on many factors, including temperatures, site water holding capacity, rootstock, grape variety and more. We want to ensure proper shoot and cluster development and a canopy that is sufficient to ripen our fruit later in the season, so as a regular part of our routine, we develop and alter irrigation schedules weekly.”

  “At the post-fruit set, water is applied on a more prudent basis to control excessive canopy growth and focus on cluster size and berry development versus lateral shoot growth. It really is a fine line between discouraging excessive growth versus maintaining the health of the canopy to ripen fruit. In-season watering can vary from six to 12 gallons a week per plant early on, versus two to four gallons closer to harvest. Post-harvest, we’re looking to keep the canopy viable for as long as possible to ensure proper carbohydrate storage for next growing season.”

  Gregory said that all irrigation systems require infrastructure both in the field and at the control center. Field infrastructure includes the PVC needed to move the water into the fields, the risers to get the water into the drip tape and the pressure gauges to ensure consistency. The control center infrastructure is usually centrally located and includes things like electric solenoid or manual valves, backflow prevention, chemical injectors and water filters. Controlling your irrigation system depends on the vineyard’s situation. It can be as simple as a valve to manually turn the blocks on and off to a remote-control box that allows for scheduling different timing and length of irrigation sets. There are many options, but it all comes down to available resources and time. A smaller vineyard with an on-site manager can get by manually. Still, larger-scale vineyard operations over multiple sites would benefit from and be more efficient with a control box to schedule system operations. Prices vary based on how intricate your system is.

  “There are things to think about when choosing and installing an irrigation system,” said Gregory. “Try to forecast ahead to ensure your water supply will meet your irrigation needs, especially in a drier year. If not, you may need multiple wells or water storage tanks to meet demand. Additionally, you want to determine if you or someone else will be available to be out in the field when necessary to open and close the valves to change blocks. If not, can you acquire the resources needed to put towards a control box that can do these tasks on a preset schedule? Lastly, segmenting your vineyard blocks based on soil types and water needs can help ensure your plants get the water they need to thrive. For example, we farm a specific vineyard and section off the top of a hillside into its own block so we can provide for the needs of that block, compensating for soil type and exposure.”

Baseline Water Requirements

Water requirements, as expected, are influenced by several factors, including vine age and density, cover crops used (if any), rootstock and actual climate conditions (rate of rainfall with evaporation rates) under which they are grown. Additionally, the grape variety can play a role in baseline water needs. For example, red grape varietals typically require less water than white varietals, and grapes traditionally grown for aromatic and lighter styles of wine demand more water to minimize water stress or loss than those produced for medium to full-bodied wines.

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