The godfather of Australia's organic wine industry is unlocking the power of Arundo grass for biochar and cleaning up wastewater, while using a deceptively simple way to keep the notorious super spreader in check.

Depending on which country or state you farm in, or who you talk to, Arundo grass is either the devil's own creation or the great saviour. Extensively cultivated throughout the ages in Asia, the Americas, the Middle East and North Africa, Arundo grass has long been cherished for its many uses. This stout, fibrous plant has been used over the centuries in papermaking, construction, medicine, musical instrument making and as a food source, until it was progressively displaced by more modern materials throughout the 20th century.

In recent years, however, Arundo grass has been making a comeback of sorts in many parts of the world. Arundo (also known as giant reed, bamboo reed, Spanish reed and elephant grass) is gaining increasing attention due to its many applications, especially in the areas of biomass power generation, bioethanol, biogas, and combustible pellets and briquettes. It also holds huge potential for rehabilitating polluted soil and groundwater (phytoremediation), furniture and papermaking, forage feedstock and, as this article will explore, biochar.

The new-found enthusiasm around Arundo has been tempered by concerns about the fast-growing, perennial plant's highly invasive qualities.

The new-found enthusiasm around Arundo has been tempered by concerns about the fast-growing, perennial plant's highly invasive qualities. Arundo is of particular concern when it takes root around waterways and in flood zones. A member of the reed family, this non-sexual plant produces very few seeds; however, rushing waters break away clumps of rhizomes and stems and carry them downstream where they eventually take root. Although dispersal is gradual, left unchecked the plant can do significant damage to landscapes. In California, vast tracts of riparian habitat have been overrun by Arundo, devastating natural biodiversity and creating a ready fuel source for the region's ever-increasing wildfire problem.

So how to best manage Arundo? How can farmers safely contain its spread while taking advantage of its many attributes and applications? We spoke to the godfather of Australia's organic wine industry, David Bruer, to find out why he champions Arundo, how it contributes to soil health on Temple Bruer's vineyards, and the surprisingly simple way he manages this Jekyll and Hyde grass.

The Temple Bruer experience

Each harvest brings Temple Bruer one step closer to reaching net zero carbon emissions.

When David and Barbara Bruer planted their first vines at South Australia's Langhorne Creek in 1973, they made a commitment to grow quality produce based on sound production processes that would contribute to the Earth, not deplete it. A trained chemist, David also joined the Organic Vignerons Association of Australia in the mid-eighties and helped them redefine their standards from a scientific point of view.

Since those early days, Temple Bruer's vineyards have continued to expand at Langhorne Creek and further afield to Eden Valley and Loxton. Even though Barbara passed away some years ago, David carries on with her vision to make Temple Bruer carbon neutral and to ensure each vineyard and every bottle of wine achieves an A-grade organic certification with NASAA (National Association for Sustainable Agriculture Australia).

Healthy soil free of artificial chemical inputs is a major key to organic certification. One of the processes critical to healthy soil for Temple Bruer is biochar. Ten years ago, David saw the potential of growing Arundo grass for biochar and planted out a 1.2-hectare paddock at his Langhorne Creek property. David sourced his stock from a fellow farmer in the district who grew Arundo to produce reeds for woodwind instruments.

When it comes to containment and management of this notoriously invasive grass, David's solution is breathtakingly simple. 'Arundo rhizomes cannot spread across compacted ground, so we simply surrounded our growing area with roadways,' explains the winemaker. 'As long as the crop is planted away from waterways and flood zones and is fenced in by compaction, Arundo is easy to manage.'

When it comes to containment and management of this notoriously invasive grass, David's solution is breathtakingly simple.

Given the simple and effective containment measures, David is surprised that Arundo is still considered a pariah within agricultural circles and regulatory bodies (its cultivation is illegal in Queensland and New South Wales). 'It's an incredibly fast-growing crop, with a lifespan of well over 20 years,' says David. 'When the crop reaches between 3 to 5 metres, we run a modified sugarcane harvester over it, cutting the plant about 10 centimetres from the ground and into lengths of around 20 centimetres.'

Temple Bruer's Arundo field yields between 40 to 50 tonnes of dry matter each year and requires virtually zero maintenance. When the harvested piles are ready, they are fed into the winery's pyrolysis kiln, which David had fabricated locally. Occasionally the Arundo is joined by oak inner tank staves that have reached the end of their lifecycle. Then the biochar is charged with winery compost such as nutrient-rich yeast lees and vine cuttings as well as lucerne, which is specially grown on farm. Once the biochar is ready, it is simply spread beneath the vines as required.

Biochar and beyond

So, what's the big deal about biochar? Biochar can hold up to four times its body mass in water, which leads to significant savings in irrigation. Once activated with compost, microbes thrive within its open pores, making nutrients more available to crops while improving the overall soil profile. And, of great significance in these carbon-focused times is that 1 tonne of biochar can capture 3.5 tonnes of CO2. So, not only is biochar improving Temple Bruer's soil health, it's also helping the winery achieve the coveted carbon neutral status, without resorting to the purchase of carbon credits. When it comes to David's choice of Arundo over other biomass crops, it was a no-brainer. 'Arundo's the highest carbon-fixing plant of all plants,' says David. 'It's 10 times more effective at carbon work than Tasmanian blue gum.'

Arundo is super-efficient for phytoremediation, the natural process that uses living plants to cleanse contaminated soils and groundwater.

Besides making the most of the overall soil health and carbon sequestration benefits of Arundo, the Temple Bruer team are also putting their crop to use as a low-cost way of dealing with the winery's wastewater. Arundo is super-efficient for phytoremediation, the natural process that uses living plants to cleanse contaminated soils and groundwater. 'The reed is incredibly salt tolerant and can grow on 25% seawater,' says David. 'So we pump our tank-cleaning residue straight onto the paddock and the Arundo cleans it up. It's Mother Nature's great decontaminator.'

While David's work with Arundo may have raised a few eyebrows, it's also attracted the attention of researchers. Temple Bruer is currently running a multi-year research trial in partnership with the University of Adelaide to study the efficacy of biochar. A series of 2.2- metre deep pits have been created on-farm to contain compost with differing biochar ratios ranging from 100% biochar to 100% compost. Vines have been planted on top of the pits to measure everything from growth rates to fruit quality. Once the ideal ratios are worked out, Temple Bruer hope for even greater yields, while the researchers hope the findings may tip the risk-benefit ratio of cultivating this much-maligned grass into Arundo's favour.

So, what else does the future hold at Temple Bruer? David and his team have also planted out a 55-square metre field at his Loxton vineyard as a backup and as a springboard to further Arundo expansion. As for processing, there are big changes afoot at Temple Bruer too. Long dissatisfied with the efficiency of his on-farm kiln, the ever Earth-conscious winemaker has come to an arrangement with a more sophisticated local kiln operation so that the Arundo will not only produce biochar, but will generate electricity for the wider community as well.

David has long been a lone wolf when it comes to appreciating the virtues of the devil's grass, but his faith, persistence and breathtakingly simple containment solutions may soon open the eyes of more farmers, researchers and regulators to its healing possibilities. In a nation where great swaths of our country are in dire need of rehabilitation and rejuvenation, and in a world where carbon sequestration is now seen as a matter of survival, David is proving that when properly managed Arundo can be part of the solution. Now that's something worth raising a glass to!

Editor's note

Vale David Bruer 1945-2023

The entire team at Growing Country were deeply saddened to learn of David's passing in October. It was an honour to spend time with him, and we cherish the knowledge and laughter he so generously shared with us.

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