By Rebecca Shortt, OMAFRA Engineer
Hazelnut trees in maturing orchards can survive moderate periods of drought but this doesn’t mean they will be productive. Are you concerned about providing a heathy start at tree planting and during establishment? Nut fill? Larger nuts? Higher yields? Are drought-stressed hazelnuts more susceptible to insect pests and diseases? It may be time to review your irrigation approach.
Hazelnut trees should be irrigated every year during the periods of low rainfall. Irrigation is most important in planting establishment to promote adequate root development. Sufficient water must be used to wet the entire rooting zone. Adequate water is critical during the nut fill period from mid-July to mid-August.
The water requirement of Hazelnut trees is directly related to the canopy size (the number of leaves). Keep in mind that your grassed alleys will also be competing with the trees for water.
In the hottest weeks of the summer in southern Ontario potential plant water use is typically 5mm/day.
If we assume the following canopy sizes, the daily irrigation requirements are as follows:
| Canopy Size | Water Demand per tree on hottest days of summer (5mm Potential ET) | Approximate planting year |
| 2ft x 2ft | 1.6 L/day | Planting year |
| 5ft x 5ft | 10 L/day | Year 2 |
| 7ft x 7ft | 20 L/day | Year 3 |
| 8.5ft x 8.5ft | 30 L/day | Year 4 |
| 10ft x 10ft | 40 L/day | Year 5 |
It may be possible to irrigate by truck and tank in the establishment year but as the trees grow and the water demand increases a tank and truck (and employee) cannot keep up.
This is what it would take in the establishment year to water by truck:
Assume 270 trees/acre (10ft x 16.5ft spacing)
864 L/acre/every other day
A bit more than one truckload per acre every other day (truck tank pictured below is 775 L)
At 15 L/min flow from a typical garden hose, it takes ~1 hr to fill the tank on the back of the truck for each acre.
By Year 5, the trees would require 10,800 L/acre/day or 14 truckloads per acre per day.
Irrigating by truck is a labour costly approach to getting enough water to growing hazelnut trees.
For questions about establishing an irrigation system look at OMAFRA’s irrigation page http://www.omafra.gov.on.ca/english/engineer/irrigation.htm
