Avocado Irrigation Guide
The following case study shows you how the avocado irrigation system can be easily set up. This would suit any avocado installation.
Beside is an example of a new avocado tree with a wind shelter at 1m x 1m
SuperNet Sprinkler
Netafim SuperNets are the most common sprinkler we specify for an avocado orchard system. The sprinklers are pressure compensated, with a lot of flow rate options. The press-fit fittings make installation very easy for anyone new to the industry.
The most common nozzle size is between 40 - 70 L/hr.
The common method of installation is to install a supernet with a short-range spinner complete with deflector, giving you a radius of 0.9m.
When the trees get to 2 - 3 years old, the deflector is broken off, giving you a radius of approx 2 meters.
Only when the trees reach 7 - 8 years of age, and the canopy exceeds the 6m diameter, do the spinners require a change to a long-range. giving a radius of 3.5m.
with Deflector
without Deflector
Installation of the SuperNet sprinkler is fairly simple.
A simple rule to follow: put one sprinkler next to each tree.
The 4mm tube connection is easily punched into the lateral line that runs down the rows. Tube lengths are available up to 2m in length
The Design
The design for an avocado orchard is fairly simple, and it is all determined by a few features.
- Plant spacing &Â Orchard layout
- The plant spacing and layout of the orchard will help determine the pipe size and fittings you will require.
- Flow rate & Pressure
- The flow rates and pressure available at your orchard will determine the number of supernet sprinklers that can operate at one time
- This will help determine the number of zones required
The following layout is an example of how you can set up your system. The design we did for Chris was a larger orchard that had 4 x 30,000 litres water tanks available and 182 avocado trees needing irrigation.
The system used 182 x 50 L/hr SuperNet Sprinklers which is a total of 9,100 L/hr
The longest row was roughly 130m with 32 trees.
Mainline
The systems mainline determined by the flow rate, pressure, and size of the orchard. For larger orchards, a cost-effective option is the PVC 5.8m Pipe. Other common options are LD or MD Alkathene Pipe.
The pipe size can restrict the flow rate of the water due to friction. For larger blocks, it is best to consult with one of our experts.
Sub-mainline
For a lot of the sub-mainlines, we run Lateral Pipe. The lateral pipe is rated to either 3 or 5 Bar and is ideal for supply pipe to the Sprinklers. The fittings required can be easily inserted and sealed with a ratchet clip.
Recommended lateral line size is 19mm or 25mm.
- For this design, we went with a 50mm PVC Mainline and 25mm lateral Sub-main. The PVC mainline runs to the middle of the orchard with the sub-main teeing off at that point.
- Running the mainline to the centre of the block, reduces the size of the lateral pipe on either side of the mainline, as only half of the water runs in either direction.
The Pipe
Using the longest row of 130m x 32 trees we can determine the pipe size and friction loss.
32 x 50 L/hr = 1600 L/hr
1600 / 60 = 26 L/min
With the flow rate and length, we can input this into the pipe headloss calculator to help our decision on which pipe size is required.
This head loss and all the other friction losses within the system are then factored together to determine a duty point or pump size.
Contact our experts for this calculation.
The Pump
Now with a large water supply, knowing the flow rates and pressure loss of the system, we can find a pump to suit.
SuperNets require 2-4 bar pressure, and due to the large water supply, we can create fewer, larger zones, saving money.
The CEG Ecojet 1500 was the pump that we supplied for this job. It could do a maximum of 100 L/min and 5.5 Bar pressure. We can comfortably split the system into 3 x 50 L/min zones with this pump.
Using the pumps performance chart it shows the pump operates at 3.5 bar at 50 L/min. Deducting the system headloss, we still have a good 3 bar to operate the sprinklers.
The Controller
Chris's system didn't have access to AC power; we have gone for the Hunter Bluetooth Node controller. A DC controller that runs off 2 9V batteries. These batteries are capable of 2-year lifespan.
This option gives Chris the functionality to go to one controller and manage all 3 zones, and the reliability of having the system operates even when he is away.
The Node Bluetooth has the best functionality in the DC controllers and is the easiest to set up.
Rain Sensor
With this system, we also provided a Rain Sensor. This was installed on a post in the open of the orchard. This allowed Chris the safety of not wasting water on irrigation if it was raining.
The sensor is wired into the DC Controller and turns off all scheduled watering if raining.
No water wastage and no overwatering the plants.
Have a look here at the wishlist of all the components used on Chris's design.
Adjust the quantities to suit your system and the number of trees.
This list is excluding the pump, for more information on pumps, have a look at the link above to The Pump Shop.