Soil management saves dollars for Adelaide Hills orchard

19/07/2007 4:19:05 PM

The Green family has been growing fruit at Montacute in the Adelaide Hills since 1872 and if Geoff Green has anything to do with it the land will be in mint condition for future generations to continue the business and tradition.

Geoff (pictured right) and his two brothers, Bob and Barry, grow cherries, lemons, and stone fruit on a steep, picturesque 22-hectare property called Montacute Valley Orchards, no more than 20 minutes from the city. Over the past decade, they have focused heavily on ensuring their most important asset, their soil, is healthy.

As a result of a recommendation from another Adelaide Hills orchardist, Geoff got in touch with Bryan McLeod at APAL.

"What we like is that he is independent, he doesn't work for a fertiliser company so he isn't pushing their barrow. He is completely neutral and that is what we like. He also has extensive knowledge of soils and leaf tissue analysis," Geoff says.

Geoff admits that Bryan took them out of their comfort zone and they were not entirely sure what to expect, particularly when they were advised to not put on as much fertiliser.

Initial soil testing on the intensive, conventional, close planted irrigated orchard revealed low calcium, low organic matter, and excessive phosphorous, which Geoff attributes to the use of NPK fertilisers.

"Years ago we’d put on NPK fertilisers whether the crop required it or not, mainly out of habit, but probably out of a lot of ignorance as well,” Geoff says.

“Bryan’s changed that by only adding what we need so we’re not getting the waste we were previously.

“He’s saved us a lot of money over the years.

Fertiliser cut back by half

“The biggest thing that Bryan has done for us is allowed us to cut back our fertiliser usage by more than 50 per cent. So cost-wise it’s been beneficial and good for the environment too.”

Not only are the Greens impressed with slashing their fertiliser bill, soil improvements have also increased the shelf life of fresh cherries by at least two days.

Geoff says their fertiliser program is more targeted now and they have done away with the attitude that more is better.

“One year Bryan recommended no fertiliser at all, just lime. We thought that was odd but it just unlocked all the previous excess nutrients in the soil and the trees did really well without it because there was a surplus there to be used,” he said.

The Greens grow a range of different varieties to meet market demand throughout the year. Cherries include Empress, Merchant, Stella, Sylvia, and Lapin. Lemons are mainly Lisbon, Eureka, and Villa Franka. Peaches feature Rich Lady, Barbara, Amparo, and Ryan’s Son. Nectarines are a mix of Tasty Gold, Summer Grand, Fantasia, and August Red.

The orchard yields 50-60 tonnes each of cherries and lemons and 30-40 tonnes of stone fruit each year. Most of it is sold to wholesalers at the Adelaide Produce Market while some is sent to Brisbane or Sydney.

On APAL’s advice, foliar spraying has become a more significant component of crop management for the Greens, with the biggest change being an application prior to autumn, just before senescence when the tree goes dormant.

“Bryan has recommended applying trace elements because they get stored in the buds and bark and when a tree goes into shutdown it starts to drag back nutrient reserves. We’ve applied a variety of things including zinc, magnesium, and iron,” Geoff says.

“It’s a kick-start for the tree so when spring comes it’s ready for full production.”

Leaf tissue analysis is conducted on the lemons and stone fruit during the growing season, which Geoff finds a useful tool for determining how a tree is performing and what needs to be done if a problem is identified.

Cherries are analysed after harvest and are given a special treatment if they have had a heavy load, indicated by yellowing leaves and low nitrogen levels.

Dwarf fescue protects the soil

Another new measure that has been introduced is the planting of dwarf fescue between the rows to protect the soil, minimise erosion, and control weeds.

Bryan has made it easier for the Greens to prepare their soil treatments by devising a special fertiliser blend that suits all applications. He has also drawn up a budget so they are fully aware of their soil and plant nutrition management costs.

With everything under control in the orchard, the Green brothers like many primary producers in competitive markets have had to think creatively about promoting and growing their business.

They have banded together with a group of Adelaide Hills cherry growers to raise awareness of the area and to sell produce at the farm gate. The growers, with the help of South Australian government agencies, have produced a map called The Ripe Cherry Trail, which indicates where cherry growers are in the Adelaide Hills.