In recent years, heatwaves, prolonged droughts, intense storms, and unseasonal frosts have devestated orchard ecosystems.

“Considering the heat dome in 2021, the extremely cold 2022 winter and 2022’s cold, wet spring, tree fruit growers have had a wildly weather-challenging past two years,” said the BC Fruit Growers Association.

According to a University of British Columbia research team, an average orchard could lose 10% of their yield due to heat damage. “We learned that an average orchard typically loses around 10 percent of their yield in a regular year due to heat damage, causing a financial loss of almost $1,000 per acre. However, after losing up to 25 percent of their yield last year because of record high temperatures, these farmers are bracing for things to get worse,” said Matt Bagley, UBC student.

Maintaining optimal temperatures is essential for maximizing plant growth, productivity and overall plant health. Cooler temperatures can extend the growing season which provides more time for the fruits to accumulate sugars, develop taste and get larger in size. These temperatures also result in higher retention rates and ultimately increase the overall yield.

On top of improving your fruit quality and yield, cooler temperatures also create a less desirable environment for pests and diseases. Some pests and diseases thrive in hot, dry conditions. This can help minimize pest infestations and disease outbreaks, which reduces the need for chemical interventions.

A cooling irrigation system is a type of irrigation system that is designed to provide both irrigation and cooling benefits to plants, especially for orchards.

It involves the application of water in a controlled manner to create a cooling effect through evaporative cooling. These systems create a more favorable environment for apple trees and improve fruit production.

It combines irrigation and evaporative cooling techniques to reduce heat stress on the plant and enhance their overall health and productivity.

A pump or pressure system is responsible for providing the necessary water pressure to ensure proper distribution through the system. It maintains the desired flow rate and pressure required for the system to function effectively. Franklin centrifugal and submersible are common products used for pressure and pump systems.

Filters are installed within the system to remove any impurities, sediments, or debris present in the water supply. The filtration helps ensure that the water delivered to the misting nozzles or sprinklers is clean and free from potential clogging agents that could hinder their performance. Depending on your needs, a few popular filters include the Netafim Sandstorm, Netafim Screenguard and the Netafim Automatic Disc Kleen.

Valves, such as the ones made by Dorot or Irritrol, are used to control the flow of water within the cooling irrigation system. They allow for adjustments in water pressure and flow rates. Pressure regulators such as Netafim’s Planet regulator ensure consistent and optimal water pressure throughout the system.

Misting nozzles or sprinklers are the devices responsible for converting water into fine droplets or a mist, depending on the specific cooling requirements. These nozzles or sprinklers are strategically placed within the cooling area to effectively disperse water. The most common cooling irrigation product used in applications like orchards is the Nelson S7 Spinner.

BC Fruit Growers Association

Micro-sprinkler systems use small sprinkler heads positioned at ground level or slightly above to distribute water in a fine spray pattern. These systems are designed to provide localized cooling around the tree base or within the tree row.

This involves the installation of misting lines or nozzles above the tree canopy. These systems release a fine mist that evaporates, creating a cooling effect as the mist interacts with the surrounding warm air. Overhead misting systems are commonly used in apple orchards to reduce heat stress on trees during hot weather conditions. A common product used in an orchard is the Netafim VibroNet.

Fan-jet cooling systems utilize high-pressure pumps and specialized nozzles to generate a high-velocity air stream combined with water droplets. The air-water mixture is directed towards the trees, creating a cooling effect through evaporative cooling. Fan-jet systems are effective in large orchards as they can cover a significant area and provide efficient cooling.

Fogging systems, such as Netafim CoolNet foggers, create a fine mist or fog using a nozzle. These systems disperse tiny water droplets that remain suspended in the air for an extended period. The fog cools the surrounding environment as it evaporates. Fogging systems are particularly useful in areas with high temperatures and low humidity, where traditional sprinkler systems may not be as effective.

Having the right layout and design supports efficient irrigation and water management practices for your orchard. After determining water sources and soil types, irrigation systems can be designed to deliver water precisely where it is needed, minimizing water wastage and ensuring optimal orchard hydration. Proper drainage systems, or terracing can also be incorporated to manage water runoff, prevent erosion and conserve water resources.

Knowing your water source and how you’ll distribute water is crucial for cooling irrigation systems. Having enough water supply capacity, proper piping or tubing design, and an efficient distribution network ensures that the system delivers the required amount of water to each cooling zone. An optimized design prevents water wastage, minimizes pressure fluctuations, and ensures coverage. This results in consistent cooling across the agricultural space.

The placement and configuration of misting nozzles or spray heads are critical for orchard cooling. Proper nozzle selection, spacing, and orientation to trees ensures even distribution of water droplets over plant surfaces. This ensures that the cooling effect is uniformly applied to all parts of the plants, minimizing the risk of uneven cooling or missed areas. Careful consideration of nozzle placement in relation to plant height, density, and growth patterns helps optimize the cooling efficiency of the irrigation system.

Traditional cooling methods in orchards typically involve using natural means to lower temperatures and mitigate the impacts of heat stress on trees and fruit. Common traditional cooling methods can involve shade structures or windbreaks.

However, natural cooling methods are generally ineffective since they have limited control. Methods such as shading and windbreaks can’t adapt to changing light and weather conditions during the growing season.

A sprinkler cooling system is a method of orchard temperature control that utilizes water sprayed through sprinklers or spray heads to cool the surrounding environment of the trees. The sprinkler system releases water droplets into the air, creating a cooling effect as the water evaporates.

Targeted cooling irrigation systems provide cooling directly to specific areas of the orchard. Unlike traditional cooling methods that cool the entire environment, such as air conditioning or large-scale cooling systems, cooling irrigation systems focus on the plants themselves. This targeted approach minimizes energy wastage by cooling only the necessary areas, reducing overall energy consumption.

Evaporative cooling, is an energy-efficient process. By spraying a fine mist or water droplets onto the plant surfaces, the water evaporates and absorbs heat from the surrounding air, resulting in a cooling effect. Evaporative cooling is a natural and energy-efficient process that requires significantly less energy compared to mechanical cooling methods.

Cooling irrigation systems, like any other agricultural practice, have impacts on the surrounding environment. They may impact soil health and erosion rates, especially if not properly managed. Over-irrigation or inadequate drainage can lead to waterlogging, soil compaction, or nutrient leaching.

The effect on biodiversity and habitat conservation should be considered when laying out and designing a cooling irrigation system. By integrating conservation measures into the system design, such as leaving buffer zones, and using eco-friendly pest control methods, farmers can support biodiversity and contribute to a sustainable environment.

With increasing labour costs and tighter profit margins, you can access government funding to offset the costs.

In British Columbia, the government is offering an “Extreme Weather Preparedness for Agriculture” Program. Approved applicants can get up to $35,000.

Contact us to get a system designed specifically suited for your orchard, or download our full catalogue of all our products, including cooling irrigation products.

Sources

1. 1. Nelson Irrigation – Cooling
   2. BC Tree Fruit Production Guide – Irrigation Management
   3. ScienceDirect – Water and Carbon Fluxes in an Apple Orchard During Heatwaves
   4. UBC Sauder – Protecting B.C. fruit orchards from climate change
   5. ONfruit – Irrigation Timing in Fruit Trees
   6. Fruit & Vegetable – Frigid Spring Could Freeze B.C. Orchardists Hopes