FROM composting to record keeping, building up beneficial insect populations and collecting on-farm carbon sources to their latest innovation – cultivating fungi to battle yield-stripping diseases – Bob and Judy Howard have continuously ventured into untried management areas, basing their decisions on science and the experiences of other agriculture industries.
Their willingness to move outside industry safety zones has meant their 5500 macadamia tree orchard “Highgate” at Newrybar, near Byron Bay, is producing up to five tonnes a hectare of nut-in-shell, well above the industry average of about 3t/ha.
More significantly, production has continuously increased even though the orchard has moved to the closed canopy stage, where yields traditionally decline.
The Howards have not used chemical fertilisers for four years, and are now in their second season of not spraying, which has dramatically cut their input costs.
A former geologist and nurse from Western Australia, the couple purchased the farm in 2002, looking for a business they could run together.
Previously dairying country, macadamia trees were planted on the Krasnozem soil “Highgate” in the early 1980s. When the Howards arrived, the biggest challenges were erosion and declining yields.
Most of the property is on a five degree slope, with some parts as steep as 12 degrees, and the trees were showing symptoms of decline with woody tops and poor leaf growth.
The farm had been using conventional systems of Roundup under trees to control weeds, harvesting off bare soil and chemical fertilisers.
The Howards went to work on increasing organic matter and humus, bringing in a small spreader from WA, a commercial collection mower from Italy and a chipper to make compost from grass clippings, prunings, old nuts and husks.
“When I started I followed the science strictly – getting the ratios right, measuring temperatures – but as the years have gone by I’ve learnt how to get equally good results without so much time and effort,” Mr Howard said.
“It became obvious that even healthy macadamia trees will grow a dense surface matt of very fine roots into organic matter placed around the trunk, obviously not for support and presumably after nutrients.”
This formed the concept the Howards today base their management on – soil health is king.
“The aim is to ensure the nutrients are available to trees whenever they are required,” Mr Howard said.
“Compost is not a quick fix. It takes time for natural biological process to develop after conventional systems have removed organic matter from the soil, but the final result is a sustainable orchard that will be productive for many years.”
Despite the fact “Highgate” has high density plantings (five metre rows of trees 3m apart), the Howards have not yet had to start removing trees as is standard industry practice, as their yields are improving rather than declining.
The Howards now make 500 cubic metres of organic matter (also collecting green waste from neighbouring properties) and mix it with chicken litter as it is put out.
It is applied at 10t/ha on average, just after harvest.
As well as increased nutrient holding capacity, the benefits of a topsoil rich in organic matter and humus include rapid decomposition of crop residues, better water infiltration, increased water holding capacity, granulation of soil into water-stable aggregates and improved drainage.
Compost is also used to control erosion at “Highgate”. It is put on the bottom side of trees, 50 centimetres wide by 30cm high, to reduce and slow water flow from the orchard in times of heavy rain.
The Howards have also built a concrete pad for compost on a slope which allows leachate, or rain run-off, to be drained, pumped to 30,000 litre tanks, recycled onto the compost pad and used as a soil drench applied to the trees.
In last year’s heavy, continual rain, soil loss in the orchard was minimal.
“Environmental factors always outweigh management factors, but the more sustainable you can make the farm, the more you are protected,” Mr Howard said.
“Our farm can now handle 150mm a day, but we can get that amount in a matter of hours so there is still more work to be done.”
The Howards are now trialling the use of logs, recycled from windbreak trees, placed between trees and straddling gullies, with wood chip placed upstream and compost on the downstream side, all covered with fresh mown grass.
The idea is to create a leaky dam every 8m along the gully to slow the water flow and control erosion in areas of concentrated flow.
The control of erosion via compost was one of the key points that singled the Howards out as industry leaders, according to Australian Macadamia Society chief executive officer Jolyon Burnett.
“They’ve had excellent success – their yields would put them in the top 10 to 15 per cent of producers,” he said.
