3 minute read
Revealing groundwater’s denitrification capacity
Growing for the greater good
The feeling of doing something for the benefit of the environment is what Devin Westley loves about growing plants.
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Devin Westley is the Production Manager at Southern Woods Nursery.
After dabbling in ecology and microbiology in the early days of his tertiary studies Mr Wesley then decided to study horticulture and horticultural management at Lincoln University. After this he went to Southern Woods as part of his work experience and since then, has never left.
His role sees him tackling a range of tasks and water management was a key one of them.
“It’s a really important part of what I do.”
Irrigation systems ranged from overhead micro sprinklers to more direct drip irrigation for individual plants and was run with a system called Galcon GSI, a 4G-based irrigation controller specifically for horticultural growing.
Water for irrigation was pumped from an onsite well and there were 80 irrigation zones across the nursery.
“Plants are at different growing stages, different pot sizes and different plants need different amounts of water which is why it is crucial we have different zones.”
He said how much they irrigated was of course dependent on weather conditions and the time of year but generally in the winter they were irrigated twice a week, and summer up to twice a day.
During peak irrigation this meant they were watering for around 16 hours a day across different zones with capacity to have different zones going at different times using multiple pumps. He said the aim was to give the plants enough water that they were wet through but there was no water running off them to prevent nutrient leaching.
Fertiliser was incorporated in the medium the plants were grown in and the size of the plant and how long the plant was going to be in the nursery determined the amount of fertiliser they got. This could be anywhere from a five month to a 14-month release, which could be topped up if required.
When it came to pest and disease control on plants Mr Westley said they did not over spray.
‘’We try not to put excess costs on the plants.”
The prunus species (fruit trees) received a monthly copper spray and everything else got a blanket spray about twice a year, and the myrtle species were sprayed monthly as a precaution for myrtle rust.
For the first time this year they had used ladybugs which were natural predators for pests such as mealy bug and it was something they would likely continue in the future to reduce chemical use.
Bird control was also important, but this tended to be more of an issue for seedlings and so they were grown in tunnel houses to avoid damage.
The three main tasks of Mr Westley’s job were monitoring irrigation, meeting production targets and making sure everything was working for his staff.
“I really enjoy the water management side of things and it has gotten more precise and technical in the time I have been working in this job and I’m sure it will continue to in the future.”
Mr Westley said he appreciated both working inside and outside in his job and got the greatest satisfaction from seeing the plants he grew planted out in a large project.
“Visiting places where your plants have gone is great as it’s such a tangible achievement, whether it’s in a new subdivision or the side of a motorway, I know I’ve grown this stuff and it’s going to be there for years to come.”
During peak irrigation season irrigators were running for around 16 hours a day across different zones.
