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Biochar project at PRI Australia
Posted by Jesse Leavitt about 10 years ago
Biochar was inspired by the discovery of black earth in the Amazonian soils. Today we've singled out biochar for its benefit. In this post I answer the question.. "Is biochar worth it?"
Biochar, it can save the world! Well..can it? After reading biochar revolution, and listening to people who are involved in the biochar movement, you really start to think "wow, I can really save the world!" Now biochar has some great benefits, like creating habitat for micro organisms and carbon sequestration, however the production of char consumes a substantial amount of woody material. (See photo 1)
For the initial process the device I used to heat the biomass was a 44gal barrel with meandering holes drilled at the base of the barrel (see photo 2) Inside the 44gal barrel is a 30gal barrel with a sealed lid to prevent the biomass from being exposed to oxygen.(see photo 3) The biomass decomposing at high temperature in a low oxygen environment is properly termed as pyrolysis. This process is essentially what produces the char. The idea is simple but takes good timing, because the inner chamber must remain at a consistent temperature, ideally 400 Celsius for a duration of 24 hours. Now I didn't use a temperature gage, nor did I burn for 24 hours. The thing with my kiln is that it had a flush of oxygen throughout the burn. This had caused my fuel to burn very quick, and at a very high temperature. I ended up running out of fuel after 5 hours of burning. By some fluke I ended with a product that Geoff Lawton claimed to be the best char he'd ever seen!
(See photo 4)
So after having gone through the process of producing biochar, I wanted to put it to good use. With fresh biochar it's good to "charge" it with micro organisms. You can do this by soaking it in compost tea, or even urine. I wanted to experiment with mine by using it as a layer in an inoculated compost. The theory I read suggested to spread the char on each high nitrogen layer, and this will allow nitrogen to remain in higher concentration. Therefor decomposing the pile at a faster rate.
(See photo 5)
So is biochar worth it? I would say using the method I did, It wasn't. I say this because for one I burned a hell of a lot of fuel, and the net return was minimal. Also biochar isn't a silver bullet. Although it can be used as another tool in the tool box, it's not going to save the world on its own.Don't worry though, I haven't given up entirely yet! I will be back with another update on how I used an even simpler method that has a low input, and high return..so stay tuned!
Until next time,
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Since your conclusion isn't yet settled, my intitial reaction is to say piss on it. So I'll have to try this so I can. Hurry up and post this simpler method. Thanks!
Nice write up Jesse. We still have a lot of that char you made. I will try and have one of the students here do a comparison test with it and write it up. Keep up the good work.
Thanks Erik. Yeah that is a great idea, let me know how those comparisons go. In the mean time check out my new update. I discovered a much faster, and more efficient way of producing biochar.
Geoff wants you to send this to Craig so it can be posted as an article.