The design and management of Murrnong Farm has been guided by Permaculture Ethics and Design Principles. The intention is to live and farm within the limits of nature, and to operate mainly from current sunlight. While the farm does presently use some non-renewable resources such as fossil fuel to power relatively minimal use of the small tractor and petrol powered irrigation/ fire pump, with a few changes the farm could continue to operate very well without this input.
The biggest tractor use is for mowing grass between trees where it is difficult to manage grazing without causing damage to the tree crops. This tractor use could be avoided with more human labour to closely manage grazing. The additional grazing livestock would increase and diversify production, and improve fertility cycling.
Spring 2007, goats grazing on move-able tether between carob, bunya and stone pine.
Some crushed rock dust fertilisers were brought in initially, (and may not even have been necessary) but these days no fertility inputs are deliberately brought in, other than small quantities of bought food, with wastes composted on-site. The flood plain wetland does harvest some flood-borne nutrients. By far the greatest fertility factor is the management of plant growth, and the consequent feeding of soil microbial processes by plant roots. Fertility development and cycling is complex and seasonal, but on this farm is now mostly self-regenerating. Perennial tree crops are an important part of this.
Most of the food and all of the fuel wood for farm residents is produced on the farm.
In the early years some compost teas were used to help get soil microbial life going. When possible, we let plants grow to help improve the soil with their roots, and this includes some plants that are conventionally described as weeds. Then, when we need to focus available water and nutrients on productive trees, for example, we mow grass and cut back other perennial plants.
October 2008, Matthew Lewis operating walk behind slasher to mow under young olive trees.
At the very local level, trees and perennial plants are good at cycling nutrients and improving soil fertility around themselves. At the farm scale, produce is harvested, consumed on-site or increasingly sold off-site, and nutrients do move around.
Feb 2015 ‘Chewy’ the tractor powered chipper feeds orchard and forestry branches onto the wood chip compost pile, where it composts for about two years.
Feb 2015 Wood chip compost freshly placed under an orange tree (with whitewashed trunk to protect from sunburn).
Orchard and Tree Crop Management
The main pest problems (apart from birds!) have been codling moth in apples, pears and quinces, fruit fly, and black olive scale on olive trees. We have tried various commercially available products, and have concluded that these are not effective enough to be worth the expense. We find other ways to work around these pests.
Feb 2015 Chickens on free range help clean up fallen fruit, but would need to be at a very high density, possibly to the point of damaging tree roots, to have any chance of preventing pest larvae surviving in the soil. Here, they help, but are not the whole solution. Nets are to keep birds from fruit.
To manage Codling Moth (Cydia pomonella) we try to remove all infected fruit and ferment it in buckets of water to kill eggs and larvae.
Queensland Fruit Fly (Bactrocera tryoni) have been endemic in North Central and North East Victoria since at least this newspaper article in 1907. To manage Fruit Fly we try to remove all infected fruit and ferment it in buckets of water to kill eggs and larvae. Stone fruit are harvested as soon ripe enough to ripen fully off the tree, checked carefully for signs of damage or infestation, and refrigerated for at least 11 days before going to market, to ensure any fruit fly eggs or other life stages are destroyed.
From 2016 to 2018 fruit fly numbers greatly increased, destroying much of our harvest. From this we have learned what we can still make work. Some crops can be harvested clear of infestation even with fruit fly around. For example each individual fig only swells and sweetens a few days before it is ready to be picked, so it can be safely picked and refrigerated before any tiny fruit fly eggs have time to hatch. Astringent persimmons do not sweeten until after they are picked and brought inside, so are not attractive to the fruit fly while on the tree.
We have found that ants are our ally with fruit fly, in particular the meat ant (Iridomyrmex purpureus). Alongside our development of this farm, this ant has developed a network of 10 or more interconnected colonies right across our 8 hectare property. (They love our work, maybe we are working for them!) Ant numbers seem to have markedly increased since 2016, coinciding with the increase in fruit fly numbers.
Meat ants predate on fruit fly larvae, definitely in fruit on the tree, and possibly also when trying to pupate in the ground. In the photo above, meat ants have drilled into these large peaches, taking out the larvae, and also cleaning most of the rotten flesh. They have stopped this part of the pest life cycle, and have also saved the rest of the fruit from rotting. These peaches are not retail quality, but there is still a lot of superb flesh that can be cut for the house.
Fruit fly over-winter as adults in sheltered places such as around the edges of buildings. In our climate they over-winter in quite small numbers, so during late spring and early summer each season fruit fly pressure is quite low, until they breed up. We find that we can get reasonable crops from late spring/ early summer ripening fruit such as loquats, cherries, and other early ripening stone fruit.
The summer of 2018/2019 was so hot and dry that even fruit fly numbers dropped away, and although the summer was harsh, we had magnificent crops of peaches that we had thought we would not see again from here. We a
Black Olive Scale, if numbers get high, requires spraying with non-toxic white oil in about October when the tiny scale insects are outside of their protective shelters and can be suffocated by the white oil.
Oct 2014 These bronze coloured beetles appeared (to my hopeful eyes) to be feeding on black olive scale, but the detail was too small for me to see. Few trees had many scale insects in Spring 2014, and we didn’t spray white oil that year.