VILLAGE JOURNAL Chasing Charcoal
Following is a brief report on the Soil Care Expo, at the NSW DPI research station at Wollongbar, NSW, Australia, on 5th March 2008:
There were 28 display stalls, but I was there for the keynote Agrichar speakers: Department of Primary Industry’s Lukas van Swieten, and BEST Energy’s Adriana Downie. The white marquee was packed to overflowing...120+ folks watched their beautiful powerpoint presentation, if only we could have seen it...it was washed out by the sun on the white tent roof.
The point was made and reiterated that composting rather than charring condemns a very large part of that carefully captured carbon to be lost to the atmosphere...95% in less than 10 years, and usually faster, <3yrs for more labile forms, in soft biomass. Char your woody waste, compost your soft waste.
A substantial time was devoted to listing hazards for home char makers. First item was a question...is it legal? More of this later. The most disturbing hazard for me was the inhalation risk of amorphous silica. The extreme case cited was rice husk gasifier char, imported from Thailand. In this fiasco, a container in Queensland had a C content of 4%, useless for biochar, and very high content of amorphous Silicon, cristobalite, (?24%!). The DPI’s advice was to not open the container and send it back, the point being, as Lukas said: “Char ain’t char”. You must know what you are getting, or making, is safe and productive char.
It is also a challenge to home pyrolisers to get the temperatures right, 500 deg. C, and the residence times right (~1 hour), to ensure all the volatiles are burned off. The trials at the University of Hawaii of Michael Antal, using (smelly), under-charred macadamia husks, gave yield reduction in lettuce over 2 years.
The bulk of the presentation was of the details of the field trial plots on corn, rapeseed and I think peanut clover cover crop, used in a Vietnamese collaboration (sorry if that’s not quite right).
All in all I’d have to say it was a typical product of a public service ‘be safe, go slow culture’, which I applaud as good, cautious science. It’s also a little frustrating considering we already have a few 1500-year-old living proofs that say let’s just get on with it... the energy is running out to make this switch easily...
BEST (Biomass Engineering Systems and Technology) was represented by Adrianna Downie, an extremely capable engineer, as well as powerful speaker, who had a handle on the real figures during question time.
Her presentation was excellent, as an introduction to BEST’s history, and current plans, including a $2m biochar pyrolysis plant at Ballina, in the next 18 months. Currently greenwaste is transported across the border to SE Qld for power generation (by truck!) so this will be used, as well as feed stock from local timber thinnings, and to the delight of several of the attendees, the camphor laurel was recommended, especially since it coppices well, a preferred trait for biomass forest.
Although we couldn’t see the charts, the DPI field trials for the GHGs nitrous oxide (310xCO2 effect), and methane (30x) replicated the results of similar trials at Cornell University, and showed that char in soil removes almost all of these potent GHGs. Carbon credit country.
After the talk, I quickly asked if the data would be available online, or when results would be made public. It seemed to be soon, and contingent on DPI release dates for the research papers.
A 10 minute walk took us to the test plots, and we eyed-off the most luscious corn, 3 to a stalk...I was starving.
The trials procedures were committed to 6 replications of each variation of soil amendment, in each crop ... so lots of subplots! The amendments were: Lismore tip’s Triton greenwaste compost, compost with lime, compost with lime and char, char only, control (no amendments).
The corn had 2 rows as buffers around each edge, and between the double rows devoted to each soil variation. Application rates of biochar also varied, usually at 10, and some at 40t/ha, and was deposited in only the top 150mm, it seems. It was sourced from BEST’s papermill waste char, and green-crop waste chars, samples of which were distributed. These were charred at 500deg C.
Addition of fine char at 10 t/ha made it hard to see any colour change in a random handful of topsoil at first, but individual particles around 1mm were easily seen, close-up.
I tried to grab Lukas several times but the ABC and the local papers and farmers and tea brewers and all kinds of folks were keeping him pretty busy, and all I could do was wait. Finally, noticing my terrier-like persistent presence, he invited me to the ‘family lunch table’, and we talked, between mouthfuls of (GAS barbequed) hot dogs, about my two tins of charcoal samples… pine cones, fabric, wood and bamboo samples… that were circulating around the table. I felt very privileged, being there, with his lovely wife and their two kids (2 and 6, I guess), her friend, and Adrianna, and a couple of locals, including Bob Keane.
So I used the opportunity to bring up terrapreta* discussion, and my suggestion to experiment with a ‘feedlot methane reduction plan’, using 5% soft char in feed. Adriana said some goat and pig farmers were already trialing it, but hadn’t heard of ideas to add it to dairy and feedlot feeds. The outcomes are usually increased health and growth. The possibilities are the animals do the (non-fossil) inoculating and distributing of the biochar! She suggested approaching the Federal Ag Dept for research money. I also suggested the smell-reducing, self-sequestering future of charcoal-dust bionappies!... there was a delighted reaction.
Lukas explained that the DPI centre has just developed a process they are calling a Pyrogram, which takes the char sample and reduces it to ash, venting this into a gas chromatograph. This gives a signature of each char sample, and is apparently one of two in the Southern Hemisphere. They are hoping it will be an industry standard. I felt tiny, looking at my char treasures, but he graciously suggested I bring over samples and they would test them for signatures.
The golden rule if you are charring and experimenting at home is if the char smells, after you’ve collected it, then it will be several years before it is of advantage to your crops, as the biota will take that much longer to inhabit the micropore structures inside the charcoal. If it smells… char longer and hotter.
It is possible to construct small-scale charcoal making pyrolisers that reflux the gases and burn cleanly. They are labour intensive. Adrianna Downie made a point, as an engineer, that she did not recommend that option because of the difficulty in maintaining and proving standards, and on OH&S grounds, so I am relaying her concern to you. However, I continue my home pyrolising developments, and recommend bioenergylists’s terrapreta forum for the chronically smitten agricharismatics.
* Terra preta, or dark soil, is the name given to the anthropogenic soils found recently, from a Pre-Columbian Amazonian civilization, made by adding slash-and-char charcoal to the soil. This soil is still fertile 1,500 years later, and a formal, 40 year, no-amendment trial is still running. The carbon, drawn from the atmosphere and permanently sequestered, adds fertility, maintains permanent soil carbon, and is also habitat in drought and fallow cycles for the local best-practice biota, and absorbs almost all the nitrous oxide from fertilisers and methane from decomposition. In a modern pyrolysis plant, 40% char yield is possible, with energy from the pyrolysis gases refluxed to burn cleanly and produce enough heat to drive the process, dry the feedstock and supply net leftover power to a grid-interactive system. This makes about 4 or 5 bottom lines for biochar, and provides the first carbon negative power possibilities, with the option of driving the CO2 levels backwards, to pre-Industrial Revolution levels.