Irrigating walnuts

The delivery of water becomes increasingly important for walnut trees with Christmas approaching, as the temperature rises and the future kernel develops and fills the nuts. Lack of water causes shrivel of the kernel. Shrivel is dry shrunken kernel that may be rubbed off like sand from your feet after a day at the beach.

Our dam water is opaque with mud and sediment. Before passing out to the sprinklers it is filtered. In the beginning we had one filter but as the volume of water pumped increased, a second was added.


The filtration unit sits in the pump house, next to our dam. My father in law helped me plant the conifers, so we named James boulevard after him.


It is most important to maintain the integrity of the irrigation system. Leaks are the commonest problem. They vary. The tubing chewed by a hare creates an irritation. If they severe the tubing, its a headache. If the tractor slashes the 25 mm poly pipe, its a nightmare. If a sheep destroys a 50 mm central PVC pipe its a tsunami. One local walnut grower used to ride around his orchard on a bicycle listening for leaks. Its a romantic image. I use the ATV.

At this time of year the pump house fills the sprayers towed behind the tractor to deliver copper. Its quick and efficient.


Having water available for the trees creates a gnawing pressure throughout the growing season:

The level of the dam must be maintained by ordering a 4 ML delivery every 5-9 days. Its done through the web-site of the local water authority but sometimes requires a phone call to the control room should a hiccup occur. They control the delivery of water via wireless operated gates from the channel at the south end of the farm. They must have enough water in their system to meet our needs and those of all the other farmers using the channel.

The pumping system must work.

The irrigation system must be in tact and maintained.

Throughout the drought we had to get by with about 35% of our usual water allocation because of the low levels of water in Eilden Dam. The trees are much larger now and we have had full allocations for several years. Let’s hope that climate change does not take us back to those difficult times of water scarcity.

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