[Terrapreta] Agrichar (editted)

[David Yarrow]

Agrichar
Solution to global warming?
Catalyst, 23 August 2007, video documentary

University and laboratory scientists all over the world are racing to help find a solution to halt climate change. 

And an answer comes from deep in the Amazon. Not from rainforests or exotic species, but ancient soils left behind by lost civilisations. 

In the Amazon basin, huge expanses of dark fertile soil called terra preta are highly prized by farmers and ecologists alike. Full of charcoal, pottery shards and compost, they were created by pre-Colombian civilisations. Even after thousands of years, terra preta stores more than twice the carbon of other soils.

In a NSW shed, a giant toaster is making syngas by slowly burning crop residues at low temperatures. The by-product of this renewable energy is a charcoal that retains about half of the original carbon.

US bio-geochemists studying terra preta got together with Australian engineers making biofuels. The result is Agrichar technology to use charcoal by-product to bury carbon in soil where it’s needed for agriculture. 

Early results promise green energy, soil restoration and greenhouse mitigation from an affordable technology that takes more CO2 from atmosphere than it releases. 

Narration: When we think of the earth’s carbon cycle, we tend to ignore what’s beneath our feet.

We seem to forget that like oceans and forests, soils also live and breathe. 

The top few centimetres of soil are the basis of all life on dry land. Soils contain more carbon than all vegetation and the atmosphere combined.

Conference participant: People have a total dissociation with their mother, the soil. Everything we eat, everything we wear, 60 to 70 percent of industrial inputs come from soil. Yet we’ve lost that relationship.

Narration: As fossil fuels and shrinking forests overload the atmosphere with excess carbon, what part can soils play in a solution to global warming?

The answer may lie beneath the rainforests of central Amazon, in yellow soils long ago turned black—known by the locals as terra preta.

Dr Johannes Lehmann: If you live in the central Amazon, you can’t avoid bumping into terra preta. These anthropogenic soils, man-made soils are from way back, before Europeans arrived in the Amazon.

Narration: Johannes Lehmann studies how terra preta can store twice as much carbon as other soils, even after thousands of years.

Dr Johannes Lehmann: The evidence is there, and that’s what drives us. 

Narration: Along with bits of pottery, the ancient soil is mixed with charcoal.  This charcoal is different from your BBQ in that it comes from wood burned in ovens with out much oxygen—a process known as pyrolysis. 

Johannes Lehmann: So this char—organic matter—in terra preta is much more efficient doing what we want all soils to do—to retain nutrients for plants, reduce loss of nutrients, reduce the CO2 going out of the soil, enhance soil productivity, and store more carbon. 

Narration: This old idea has motivated scientists to develop a new technology, which they call Agrichar.

Mark Horstman: Could this be the new black gold that makes energy, improves agriculture, and saves us from climate change?

That’s the inspiration behind this international conference in New South Wales.

Mild-mannered soil scientists are politely plotting a global revolution.

Conference participant: One of the most important things we need to do to build this initiative into a world movement is to actually relate it back to the individual.

Narration: The ability of Agrichar to restore soils and increase fertility is one thing.

Now they’re impatient for the world to use Agrichar as a weapon against global warming.

Conference participant: The IPCC said soil carbon sequestration is proven to mitigate greenhouse gases. 

Narration: Australian of the Year is right behind them.

Dr Tim Flannery: Your technology offers a process to take carbon dioxide out of the air as fast growing plants, permanently sequestering that carbon in soil.

Narration: Tim Flannery is confident that the research by people in this room can have a global impact.

Dr Tim Flannery: We don’t know how big the potential is for using this globally.  In other words, how many gigatonnes of carbon can we sequester?  My suspicion is that it’s large.

Narration: Agrichar is especially relevant to our continent’s old, eroded soils, starved of organic carbon. 

Dr Lukas van Zwieten: 75% of Australian soils have less than 1% organic carbon. To have a healthy productive agricultural system 2% organic carbon is a level that you would like to be at. 

Narration: A little bit of the Amazon has come to rural NSW, where Lukas van Zwieten and his team are adding agrichar to old dairy paddocks.

Restoring the carbon content feeds new life in the soil and increases respiration. As the soil breathes, the gases are collected in chambers.

Dr Lukas van Zwieten: This is one of the first long-term field sites.  We hope it will last 5 to 10 years.

Narration: By analysing the gas content, they test how agrichar changes greenhouse gases emitted from each hectare of soil.

Josh Rust: We do this every two days.  These have been capped for two hours.  We look at greenhouse gases that have evolved in that time.

Narration: Adding up to 10 tons of agrichar per hectare reduces the carbon dioxide given off while tripling the weight of the crop, or its biomass. 

As well, they measure another gas that’s important for global warming—nitrous oxide.

Dr Lukas van Zwieten: Nitrous oxide is a very serious greenhouse gas—310 times more potent than carbon dioxide in the air. 

One thing was quite surprising—we didn’t expect it— nitrous oxide emission from soil is sharply reduced. 

Dr Lukas van Zwieten:, We’ve shown by adding char we can reduce nitrous oxide emission five-fold

Mark Horstman: Now the secrets of this ancient soil from the Amazon are being tried out in Australia.

This avocado plantation is the first real farm where benefit of char is being scientifically tested.  In the last ten years, Bonnie Walker brought her soil back to life.

Bonnie Walker: Our farm has 1100 avocado trees.

Mark Horstman: How important is soil health to you? 

Bonnie Walker: It’s everything. We’ve had to work hard on soil biology. What we’ve done is add as much organic matter as possible.

Narration: Today Lukas does research on Bonnie’s farm.

Dr Lukas van Zwieten It’s the first time we’ve worked on a privately owned farm to trail the char.

Bonnie Walker: We see changes in soil pH.  We see improvement in soil structure, water holding capacity. The structure of agrichar is very porous, this creates lots of surfaces for nutrients to hold onto. This is very important because fertiliser you put on will stay there.

Narration: The challenge is to make enough agrichar.

Dr Lukas van Zwieten: The more carbon, the better. And I don’t think we can produce enough char in the country to improve all of our soils.

Narration: Which brings the us here on a guided tour of Best Energies’ pyrolysis plant north of Sydney.

Adriana Downie: We’re the oldest renewable energy company in Australia.  We’ve been here working on renewable energy projects for 25 years.

Narration: Adriana Downie shows off the agricultural benefits of char with a demonstration corn crop

Adriana Downie: The one on the end is just corn plants straight in soil.  No soil amendments or additions. 

This soil next to it has 50 tons per hectare of chicken manure char. So that’s the differences we are seeing.  Char versus no char. 

Narration: But the main attraction here is the pyrolysis plant. It cooks biomass without oxygen to make a renewable syngas fuel—a flammable mix of hydrogen and carbon monoxide.

Black waste left behind is what soil scientists use as Agrichar. One person’s trash is another’s treasure.

Narration: Today they’re using ordinary garden waste.

Adriana Downie: It feeds in through a conveyor to the rotary drier which you can see spinning around.

Narration: A kiln heated to 550 degrees burns syngas.

Adriana Downie: It’s actually our own energy.  We produce in the plant that we fire it on.

Narration: The win-win is half the carbon in the biomass makes syngas fuel.  The other half stays in the char.

The amount of agrichar trickling out the end of this pilot plant won’t change the world, but making it on an industrial scale certainly will.

Adriana Downie: What we put in provides enough energy to run the process, as well as then export energy for other people to use for their processes.

Narration: Because energy is from plants that absorb carbon dioxide as they grow, it’s carbon-neutral.

Adriana Downie: From all of the technologies that are available, this is quite a unique one. It’s the carbon pump concept of taking carbon dioxide out of the atmosphere and putting it long-term into a sink.

Narration: What makes this energy so different—better then low carbon, or zero carbon—it’s carbon-negative.

Narration: The conference may be over, but these agrichar revolutionaries will continue to spread their message around the globe.

Narration: Johannes has a vision of growing energy crops to power Agrichar factories. 

Dr Johannes Lehmann: In my view, it will play a significant role to secure our future.

Dr Tim Flannery: It does seem too good to be true, but I looked at it from every angle, and I fail to see a fault in the system.

Narration: In Australia, Tim is using his influence to help make agrichar competitive

Dr Tim Flannery: The key barrier with this technology is we have to put a price on carbon.  We must put a price on the pollution that is dramatically altering our planet. Then we will see the true value in this new technology.

Narration: For Lukas, it does more than store carbon and improve productivity.

Dr Lukas van Zwieten: The beauty here is we get a tangible reduction in greenhouse gases by using char.

Narration: And Bonnie is proud to be the vanguard for the introduction of agrichar to Australian farms.

Bonnie Walker: This is a very easy way to store carbon. 

Mark Horstman: You might end up farming carbon as well as avocadoes! 

Bonnie Walker: We could, we could. It’s very exciting.

Story Contacts
Dr. Johannes Lehmann, Environmental Scientist

Department of Crop and Soil Sciences

Cornell University

Ithaca,  NY USA

Dr Lukas van Zwieten, Senior Research Scientist

Wollongbar Research Station

Department of Primary Industries 

NSW Australia

Bonnie Walker 

Tuckombil Landcare

NSW Australia

Adriana Downie, Technical Manager

Best Energies

Somersby, NSW Australia

Related Info
Johannes Lehmann’s Terra Preta website

www.css.cornell.edu/faculty/lehmann/terra_preta/TerraPretahome

International Biochar Initiative conference, 2007

www.biochar-international.org

Black is the new green (Nature, 2006)

www.nature.com/nature/journal/v442/n7103/full/442624a.html

TERRA: earth restoration & renewal

www.championtrees.org/topsoil
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