Murray's Nurseries

March 2018

Future-proofing through automation in a pine seedling nursery

Pine seedling nurseryman, Patrick Murray has turned to automation to enable him to ride the volatile ups and downs of industry requirements each year. He has developed his own automated system with a number of existing machines, enabling him to have the ability to scale up from a one-man per million seedlings operation in a slow year, to a massive 10 million seedling capacity – all within a season.

His determination to see the nursery still operating in 50 years time has led to a number of sustainability innovations around fungicide and fertiliser regimes that have the industry taking notice.

Murray’s Nurseries is sited on land that was broken in by Patrick Murray’s great-great grandfather in 1876. Operating as a jersey cow stud in the early years, Patrick's father Maurice changed direction in 1977. The farm is situated on Dannevirke silt loam, an excellent growing soil. After a stint at what was Forest Research Services, Maurice brought some of the land from the family estate and developed a nursery, growing ornamentals, natives and pine seedlings.

Maurice passed in 2010 and in 2011, Patrick, who’d managed the nursery for a year, started Murray’s Nurseries in his own name. Keen to rationalise with a short seasonal crop, Patrick decided on Pinus radiata and set himself the goal of doing it better than any other company in the field. Today the nurseries produce millions of seedlings a year with core growing contracts with Jukin, Earnslaw and Forest Enterprises.

“How can we make significant improvements in our efficiency and our stock and still offer better prices and seedling performance?”

This question, and a drive to create an environmentally and economically sustainable nursery, is what motivates Patrick Murray. Sustainable aims, both in terms of land use and the ability to ride out the volatile nature of the forest industry, have seen Patrick develop automated machinery for the nursery. The basis of nursery automation has been the seed-sower, as precision planting is a vital first step for all other automation throughout Patrick’s operation.

The machine that sits at the heart of the enterprise is an imported Italian Forgio bed-former (that creates raised beds for the seedlings). Working with local engineers, Patrick re-engineered this to attach a GPS auto pilot unit to a hydraulically side-shift seed-sowing unit for more precision. During bed-forming and planting, the GPS creates maps of the exact point where each seed/plant is, which informs the next automated tasks. This means Patrick’s machine can adjust when fitted for lateral root pruning and subsequent operations, such as spraying and topping.

The sower will be in action in 2018 and Patrick is working on additions to complete the automation of lateral root pruning, spraying and topping. He is on target for operation of this to commence in the 2019 season. Patrick is quick to point out this automation has been a long-term project. While the main work has been carried out over 5 years using only available equity from the business, he notes he has spent 30 seasons growing pine seedlings and ruminating on how to automate the system!

The next step will be automated harvesting. Patrick wants a machine that can simultaneously lift and grade 10 rows at a time, at an ambitious 8-10 plants per second.

Patrick has made the present sowing machine to work for his 10-row operation but it is also future-proofed to work with the industry standard of 8 rows. The idea is that he retains the ability to hire out his technology to other nurseries in the future.

"This land was pioneered by my great, great grandfather in 1876 and one thing that is very important to me is the continuity of this business and occupying this land. If this can be a viable nursery when it has been in the family for 200 years… that would be a fantastic thing."

Patrick’s drive for a more sustainable nursery is also a boon for his clients. Fertilisers and fungicides damage the Mycorrhizal nodules on the seedling roots. (Mycorrhizae are fungi that grow in association with the plant roots and assist greatly in the absorption of moisture and nutrients, and subsequently plant growth and health.) Mycorrhizal activity is a key to the performance of trees in a forest – so the work to create a fertiliser and fungicide free nursery is a win for all.

For the past two years the nursery has been fungicide free. They’ve done this with a novel approach. By increasing yields, they can afford a degree of loss due to fungi. Spacing of the seedlings has greatly improved yields and reduced fungi spread. The increase in the in-row spacing did mean an increase in production costs, but this has been offset by the design and development of the automated seed sower.

Further, they’ve identified the problem of ‘tipping residues’ falling out of the topper and causing Botrytis (a fungus causing a number of plant diseases). They’ve found a non-chemical approach and are also looking at different topping techniques to assure a reduction or no tipping residues in the first place. With no fungi issues for a couple of years, Patrick made the call to stop preventative fungicide spraying. A realist, he says he’s still looking at other ways to mitigate risk in regards to fungi.

Presently the nursery has managed to reduce fertiliser use by 40% with a single application of Nitrophoska at the time of sowing. Patrick is also using micro-doses of nitrogen (when a small dose of nitrogen is applied to the seedlings during insecticide spraying, about 2.5 litres per hectare). The leaf application means all of the nitrogen is taken up by the plant, so soil based leaching is not an issue.

Undercutting of the roots from the automated system is also important to assure that the soil is not stripped of organic material. Undercutting is when they harvest the seedlings by cutting the roots shortly prior to harvest. When the seedling has had a chance to toughen up again it is then removed, with 50% of it’s original biomass left in the soil (to replenish it).

Patrick is continuing his own nursery trials to establish how they can go fertiliser-free. The results so far are encouraging but he’s watching to see if there is depletion over time on the same ground or if it’s going to get better. The results from his work and anecdotal evidence from the industry are so far promising.