Australia is known as the lucky country and you would certainly think that listening to Bruce and Heidi Davison. However, the story of this modest couple is not one of carefree serendipity but of diligence, thoughtfulness, and thrift. Their journey shows fortune benefits those who can link ecology to productivity by building biological capital and saving cash.
Davisons bought their southern NSW coastal rolling downs property in 1997. Its long sheep and beef history and short stint as a dairy run off had created an unforeseen problem; soil pH of 4.6 resulting from 60 years of superphosphate and herbicide. Its long fertiliser history was the very point used to sell the 155ha property.
In 2004 they started managing the farm and as experienced organic farmers the first thing they did was stop Super and herbicides. Weeds exploded across the property, mainly African lovegrass and blackberry. The farm became a basket case.
A local consultant calculated 2.25 t/ha of 60% dolomite and 40% lime to get fertility back on track. The cost was A$33,000 to the gate and with their property barely running 40 beef cows, their operating budget was zilch. It was here the Davisons drew on their 18 years growing organic flowers for the Sydney market.
Bruce recalls how reading a primary school book (Worms Downunder Downunder by Allan Windust) changed their flower business. He began experimenting with vermicast and saw results overnight. Flowers were brighter, more upright, and developed a shelf life 30% longer than before. Within weeks competition between florists drove up their flower price 20% and fertiliser bill dropped by half.
How could they do something similar with a grass farm? Their problems stemmed from a damaged mineral cycle as evident by the long time pasture litter took to breakdown. Getting biology working became a priority but how could they get proof worms could do the trick?
Bruce did an experiment comparing consultant’s lime mix and worm juice on two 0.1 ha plots. Worm juice was applied at 20 l/ha in spring and autumn. In 12 months soil pH under lime hadn’t changed and a faint layer remained on soil surface. But pH under worm juice was 6.5 and legumes were starting to grow. That observation was all it took to scale up the idea.
This next bit sounds so crazy it’s unbelievable. Bruce set up worm farms using an old car trailer deck, a bath tub, and a 1*3 metre box from steel framing and corrugated iron lined with plastic sheet. These slap-stick vessels generate enough quality fertiliser to lift farm’s fertility. Feeding worms cow dung and kitchen scraps keeps input costs at nil.
Fermenting worm juice produces fungi and this is the secret to success. Initially Bruce applied 10l/ha of fermented worm juice to seed microbiology in soil. He did this only once across the farm but discovered more applications lower soil pH as fermented worm juice is pH 4. He now uses only non-fermented worm juice.
According to Bruce 25 ha of pasture needs just 1 m2 of worm farm to supply juice to lift vigour. Initially he tried two applications (spring/autumn) of 20 l/ha of worm juice with 80 l/ha of water and watched soil pH move to 7 in 12 months. Now he applies 10 l/ha of worm juice with 90 l/ha of water annually and soil pH is steady at 6.5.
What did the worm farm save the Davisons financially? Soil tests show the amount of calcium improved by 512kg/ha, and magnesium by 91kg/ha over 12 months. Using local fine lime and fine dolomite prices as market value for plant available calcium and magnesium (NZ Sept 2010 prices), worm juice generated A$321/ha of minerals, or equivalent of A$49,820.00 across whole property. That’s a great return on any annual investment. The only purchase was a 400 litre sprayer ($2,700) with boomless nozzles to form large droplets so not to destroy microbiology.
First positive sign applying the brew was lovegrass brix climbing from 1 to 5 within a month and then peaking at 7-10 inside 12 months. Lifting pasture energy levels means animals consume less grass to perform. Then legumes started re-establishing in areas with pH over 6. They grew up through lovegrass without being sown, another cost saving.
Furthermore, in last 18 months Bruce uses fish emulsion which doubles lovegrass brix to 15 and up to 20 with bamboo grass. Fish offal from a local processor is free and only costs freight to farm gate. Half a tonne of fish is topped up with water to seep for 3 months in an 1800 litre stainless steel milk vat that cost $400. Bruce estimates cost of making and applying his pasture brew at $10/ha.
Bruce checks when to spray worm juice by spraying a test plot first. If brix doesn’t rise within an hour, it means applying brew at another time of the month. Best time is after a full moon in spring or autumn when sap heads down the plant and open stomata drink brew in. Ideally, spray very late evening (about 30 minutes after sunset) in heavy dew or fine drizzle and pasture 15cm high (during the growing season). No problems about spray drift and needing dry conditions.
But drought proofing a property takes more than worm juice. Set stocking is what encourages lovegrass. Cattle perform poorly during drought where African lovegrass dominates pastures. It matures quickly and loses quality as nutrients move into roots. Changing to rotational grazing lowers costs and lifts farm performance by addressing these issues.
During the 2009/10 summer drought an expert agronomist visited Davison’s property to check their claim of maintaining stock numbers on lovegrass unlike district norm. Combination of rotational grazing, worm juice, and lovegrass at 15 brix allows Davison’s heifers to grow at 1.4kg/day in drought conditions. The expert took photos of stock and pastures and was deeply impressed with rotational grazing of lovegrass. At height of drought livestock numbers were equivalent to 120 cows, 200% above what they started with in 2004.
Bruce observes lovegrass out performs species like ryegrass, fescue, cocksfoot and clover throughout the dry because they all require constant moisture. Lovegrass’s tussock shape funnels any moisture down to plant base and deep fibrous roots which absorb it quickly. As a result it will grow up to 25cm after a thunderstorm whereas most species barely grow 1cm in same time. It also responds very quickly from a low grazing residual and therefore suits rotational grazing and high stock densities. Pasture renovation, spraying herbicide, and burning to remove lovegrass is what drives down profitability.
This is where another experiment signalled a new direction. Bruce mowed rank pasture and piled litter into a heap to decompose into soil. In 12 months that spot was free of lovegrass with other species like clovers, medics, philaris, prairie grass, and paspalum establishing, no sowing as seeds were already there. To Bruce it seems low organic matter encourages bulky lovegrass to grow.
As a result of this observation and their exposure to Holistic Management they now lengthen recovery periods, increase stock density, and lift post-grazing residuals. They have noticed how animals, soils, and plants respond to these changes despite always having to deal with summer drought; very wet 2010/11 season being an exception.
Longer recovery times allow pasture to mature resulting in a better protein/carbohydrate balance and less animal health issues. They no longer drench or vaccinate and breed using genetics that suit this kind of system.
Increasing stock density crushes more pasture to soil surface to feed soil microbes. Combined with worm juice, this practice helps lift soil fertility by keeping soil life active.
Post-grazing residual is around 3000 kgDM/ha even during drought. A high residual insulates soil and lengthens moisture retention. Greater solar surface area increases pasture growth rates. As a result lovegrass is being replaced by other C3 and C4 species.
By observing ecosystem processes and then designing management to compliment nature the Davisons are building biological capital without added stress of debt. Worm farms have been an extremely cost effective tool to strengthen mineral cycle by establishing and feeding soil biology. An important part of this adventure is Bruce’s monitoring to ensure soil conditions are right and altering application rates once soil pH reached 7.
Then by changing grazing management to produce and crush more litter on soil surface, Davisons are ensuring a steady food source to energise organisms and maintain soil fertility. In practicing principles of Holistic Management they’ve used livestock to change soil surface conditions and cheaply initiate a shift in pasture ecology to lift property performance.
As a result they are now part of a Dept of Environment, Climate Change and Water pair-trialled site with their neighbour. This 20 year experiment started in 2008 and involves taking cross boundary soil samples every 5 years to monitor changes from different management practices. They also have regular field days on their property to educate farmers about their journey and show their achievements.
Once soluble mineral fertilisers and herbicides stripped bare soil biology of this property, yet reintroduction of soil life through worm juice signalled a turning point and a new direction. The worm farm generates Davisons a small fortune and allows them to enjoy and share their slice of the lucky country.
John King is a Holistic Management educator living in Christchurch, New Zealand. You can contact him through www.succession.co.nz or +64 27673 7885
Bruce and Heidi Davison live near Candelo, NSW, Australia. They can be contacted at www.candelosalers.com or phone 02 6493 2131
Plant Health Solutions 