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Hi folks

As I mentioned yesterday there has been a thread running on something called biochar thread which some of you may have read. It's also pertinent because Loong has raised the question of is it safe to use charcoal ? I've been doing a spot of research and come up with the following;

First to answer loongs query

"Can I use commercial charcoal as biochar ? absolutely. While the bio-oil condensates in biochar definitely play a role in soil fertility, charcoal without bio-oil condensates has been demonstrated to produce excellent results.Although it is normally advisable to avoid industrial charcoal briquettes because the binders used during manufacture can add undesirable constituents"

obviously your charcoal contains no binder and as long as the locals are using raw timber and not treated or painted wood I guess you've got the all clear.

" What are the benefits of using biochar ??

The following benefits occur with additions of biochar

Enhanced plant growth

Suppressed methane emission

Reduced nitrous oxide emission (estimate 50%) (see 5.10 below)

Reduced fertilizer requirement (estimate 10%)

Reduced leaching of nutrients

Stored carbon in a long term stable sink

Reduces soil acidity: raises soil pH (see 5.01 below)

Reduces aluminum toxicity

Increased soil aggregation due to increased fungal hyphae

Improved soil water handling characteristics

Increased soil levels of available Ca, Mg, P, and K

Increased soil microbial respiration

Increased soil microbial biomass

Stimulated symbiotic nitrogen fixation in legumes

Increased arbuscular mycorrhyzal fungi

Increased cation exchange capacity"

heres some links that explain biochar and its uses;

A good general overview and very readable biochar

an article on biochar in Thai rice growing black soil - green rice

loads of good info and links pus some video biochar - home production and usage

FF was asking about rice straw so here's one for you ( more about producing on a commercial scale but I'm sure a man of your calibre could put it to use, bit scientific I'm afraid ) technologies for the energy use of rice straw

also a happy coincidence bearing in mind my recent post

"Biochar enthusiasts generally agree that raw biochar needs to be processed further prior to being added to the garden. Composting, or soaking with compost tea, is commonly used to charge the pore volume with beneficial organisms and nutrients. Soaking in a nutrient rich solution (examples are urine or fish emulsion) prior to composting is accepted practice."

Finally heres a PDF on building your own kiln as used in the Philipinnes to produce biochar from rice hulls on the farm


There's loads of info out there on the net and biochar can also be used as a fuel . Many hope it could be the answer to save the planet and there's plenty of ongoing research !!

happy carbonisation folks !!


Howdy Jandtaa

I tried to look at carbonisation of the rice straw but the thread really didn't have much. I did get the PDF for the Phillipine Carbonizer and it looks like a viable way to deal with the husks. I think with straw you will be constrained by the large size and the amount of air spaces in your burning (carbonizing)pile in a similar type of situation. The reduction of the straw size would possibly allow a process similar to the carbonizing of husks. I know of no way to practically cut the straw so will have to look at different ways carbonizing or just use it for composting and soil amending and look to buy some husks.

Bad news for the husk buyers out this way as there has been a HUGE Bio-Energy plant built just outside of Prakon Chai so they are buying by the 10's of thousands of tons of husks. Someone on thaivisa was saying 5000 baht for a ten wheeler delivered and that doesn't sound too cheap at all. Obviously the amount of transport is a crucial factor. Anyone else have any info on the cost of husks per ton or any other manner of purchase just for references?

Fantastic job with the sub-forum as it looks as if it has been up and running for years truly a hurculean effort and very well done. Not enough thanks could be possible and it will be truly invaluable for many. Choke dee

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Bad news for the husk buyers out this way as there has been a HUGE Bio-Energy plant built just outside of Prakon Chai so they are buying by the 10's of thousands of tons of husks. Someone on thaivisa was saying 5000 baht for a ten wheeler delivered and that doesn't sound too cheap at all. Obviously the amount of transport is a crucial factor. Anyone else have any info on the cost of husks per ton or any other manner of purchase just for references?

A 10 wheeler> That's a lot of rice husks. Do they come from a large processing plant?

Maybe your area doesn't have the small processors operating out of a shack with 1 machine. If there are any, you can usually go and shovel the husks yourself for free. Maybe we are just lucky in this area.

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Hi guys

been having another little dig around and come up with the following on possible drawbacks

Currently manufactured biochar is in short supply and is fully utilized for academic research projects. BEST Energies is purported to have a target price of AUD $200 /Mg (Mg is the same as a metric tonne) for Agrichar™. This is equivalent to USD $0.06 /lb, and would be very competitively priced.

Composting worms have been observed to be unaffected below 50% charcoal content, above which reduced worm activity could occur.

Data on the effect of charcoal on crop yields is still rudimentary – only a limited number of crops grown on a limited number of soils have been investigated. The interactions between crop, soil type, local conditions, and biochar feedstock, production method and application rate will have to be studied in far more detail before large scale deployment of biochar as a soil amendment can be contemplated. Nonetheless, there is evidence that at least for some crop/soil combinations, addition of charcoal may be beneficial

So unless you can find a cheap source of husks and make your own biochar it's gonna be difficult to apply this practically or economicaly over a large area.

I was thinking of incorporating it into some bio-intensive raised beds by composting it first with manure and rice straw etc using EM and then mixing it into the topsoil and covering with mulch. I'll build the kiln and give it a try in 6 months time when I get back.

regarding ph

Raising soil pH is biochar's most important contribution to influencing soil quality. (Source) Soil pH mostly influences the relative availability of nutrients. At low pH, aluminum toxicity is particularly harmful to plant growth. Aluminum toxicity is an extensive and severe soil problem and biochar is the most available and obvious solution that we have to combat it. Soil phosphorus availability is highly dependent on soil pH range, and thus biochar can be used to substantially increase phosphorus availability in soils that are below the ideal pH range of 6.5 to 7.0.

here's a link to a bigger kiln for farm use masonary retort kiln  

and here's a link to the bio-char field trials database terracarbon. org

It seems to be another story of an organic technique that has been used for centuries recently being rediscovered but dependant on further research and commercial enterprises investing in the building of processing plants etc . Probably good for the small scale farmer/market gardeners out here in the tropics and it's certainly worth giving it a go if you have the time and resources IMHO

cheers all J 


P.s. A by product of the carbonisation process is wood vinegar link to where it's being discussed in the organic pest control thread

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I'm interested as well. Unfortunately my internet is so bad today, can't check out the website too much, so don't know if there were plans or not.

If 500 Euros to build I would be very interested in sponsoring one for our village community. The villagers here make charcoal already, so a more efficient method with less air pollution would mean lower health risk for my family (as well as every other family in the village)

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Hi folks 

here's a link to an FAO site on a variety of kilns link

Here's the contact details of the guy that designed the masonry retort kiln (apparently he has worked in Thailand with them) maybe someone wants to email him ??

adam + partner 

Bahnhofstr. 13 

82467 - GARMISCH 

G E R M A N Y 

ph: +49-175 528 96 24 

fax:+49-180 5060 3360 3783

[email protected]

these are the only details I could find about it 

Details of the ICPS (Improved Charcoal Production System / adam-retort)

-which was developed in Burundi/East Africa and in South India near Pondicherry. Dimensions

may differ in other countries, depending on brick size and size of galvanized sheets available.

The size of the inner wood chamber: 2,4m x 1,1m x 0,95m height (volume: 2,5m3)

Thickness of walls: 0,07m + 0,04m(space) + 0,07m = 0,18m

The size of the outer wood chamber: 2,76m length x 1,46m width x 1m height

Length including chimney box and fire box: 2,76m + 0,4m +0,6m = 3,76m length

Construction time: about one week to ten days by a trained team of 2-3 workers.

Cost for material and labour: about 200 – 300 Euros depending on the situation in the country.

here's a link about work on kilns in Thailand by  The Royal Thai Forestry Department charcoal kiln testing

might be worth contacting them to see if they have any detailed plans.

But that's about it, most designs seem to be based on the 55 gallon steel drums in various configurations !!

Cheers for now J

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What about carbonizing kee vuar/moo/ghai/falang :o wouldn't need too much charging with "tea" :D At 100/300/400 Baht per ton, hmm. Too small particle wise? I/you/ we (mostly you) need to experiment.

Jandtaa to MIL...."Khun Yai, I need your stools to carbonize" :D .

I'm running a book on what she's going to hit him with first. :D The "golden liquid" night pot is 2/1 :D


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:D :D

TT I was considering attatching a sneaky syphon to the afore-mentioned night-jar !! If you you could pop up and give us a hand starting the syphonic action it would be most appreciated :D !!

Yeah It's gonna be a job persuading the missus about the humanure toilet I'm seriously considering installing when I get round to building the new house !! She's used to my crazy Ideas and generally supportive but this might be a bit much for her . Might just have to build an out-house in the veg patch and take to reading the morning paper out there :o !!

cheers for now J

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Hi folks

just came across this site biochar farms

really does cover biochars application in most agricultural scenarios including forest gardening,poultry rearing etc. Gives some suggested application rates observed yield increases etc but remains well balanced examining the possible downsides and acknowledges it could be decades before research is fully completed.Different ways to "charge" the biochar including the use of bio-digester methane sludge. Also a couple of different kilns here including a portable hi-tech one.

overall a good read if you haven't come across it already !

cheers J     

P.S. here's the direct link with construction and usage guide to this double barrel kiln closedlids_small.JPG  barrel2_small.JPG  kildback_small.JPG link

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^ The best areas for growing on our property are those that were used for fires. The soil is loose and dark, with plenty of charcoal. I've just planted on another area, it has leaves and straw as mulch, also planning to add some coconut husks and compost. Any further suggestions?

Were these fires for cooking?

I'd just like to stress that burning leaves and other waste is not the same as carbonisation.

It's well known that the slash and burn methods of the past resulted in terrible damage to the environment. The fertility of the soil was quickly depleted and the farmers moved to a new area of forest, leaving a wasteland behind.

My little plot that I'm trying to tend has suffered years of scraping up the grass and burning it. Consequently, the soil is very poor with next to no organic material.

It takes a while to make any volume of compost, so it's been a gradual improvement to date.

I think that I may have had a bit of extra luck. The river near here was dredged out a while back and the spoil dumped on the bank. A lot of reeds, soil and vegetation. Digging into the piles, it looks pretty good. Still a lot of reeds, but plenty of fibrous organic material. I think that it will make a marvellous additive to improve my sticky clay soil.

Not easy to get to though, so will be a bucket or 2 at a time

Edited by loong
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2 months ago, I prepared a small area of soil. I dug in some mature cow dung. Then dug in charcoal one half only (approx 10%, 40cm depth). I sowed various seeds and deliberately overcrowded it as I wanted to see what happens. Probably the only organic material in the soil was the cow dung.

The growth has been far superior to anywhere else in the garden that has only benefited by the addition of cow dung. The strange thing is that there seems to be very little difference between the half with charcoal to the half without. This leads me to believe that a small amount of charcoal dust found its way into the untreated side. This would mean that even a very small proportion of charcoal dust has immediate benefits.

In the half treated with charcoal, the winners are Kale and Chinese radish. I think that the carrots are doing better that side as well.

The tomatoes are doing well in both halves and are much healthier than in other parts of the garden, despite the overcrowded conditions Pak choy are doing ok, but leggy and anyway, I think the weather has been too hot.

Where I have added charcoal dust in other areas, it is looking very encouraging. I am certain that, with the addition of more organic material, the soil will be a dramatic improvement on what I started with.

I have started some seeds in bags with varying concentrations of charcoal dust, but too early to report as yet. I can only say that leaf mustard germinates at high %, but withers and dies soon after seed leaf stage.

I dug some soil from the area below where the charcoal was made. This is a sandy consistency and black.

Trying to germinate seeds in this without mixing in other soil is not good. This could be due to the high level of condensates after years of charcoal making. Grass will grow ok, but that's a survivor. The only seeds that I have manged to germinate in this soil so far are black beans, but they have only been growing for one week and so may still be using the seed nutrients. Time will tell.

I will be continuing with my experiments and let you know what happens.


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Hi Loong, Interesting posts, im also very interested in the use of charcoal or ash, i see these big forest fires around the world and after a rain or 2 they are soon growing again,although its never reported on television.

Last year, after our tamarind trees were pruned, i dragged a lot of the dead branches onto the salad beds and burnt them, then raked out the ashes ready for the rain to do its work, after a few rains, the weeds came, Mrs said dont go to farm, they are spraying weedkiller today, they overdosed on the salad beds, anyway, 2 months ago, i dug out a 9in sq hole and planted red cherry tomatoes in compost, the tomatoes where the fires were are doing so much better than the others, So perhaps its a matter of time allowing the ash/charcoal dust to get into the soil? perhaps its to harsh to start with? I can buy huge bags of charcoal here for 100 bht, do you think crushing it into dust then apply and let a few months rain would help it into the soil?

Thanks, Lickey..

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Yeah good stuff Loong

I crushed up some charcoal to a powder and "charged" it with EM before digging it into a small patch of topsoil at about 5 kilo to the square meter before sowing up with green manure. Shame I'm not there to make observations (will attempt to ask the wife over the phone )howmuchbiochar.jpg

I've now identified the soil testing kit I'm gonna buy and when I return will build the rice hull carboniser and set up some field trials using biochar .

cheers for now J

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Hello Lickey,

It may be worthwhile talking to your charcoal supplier, if he makes it himself. It's very possible that he is left with a lot of very small charcoal pieces and dust that he cannot sell. He may well sell you this at half price. It'd actually be better than half price, because more smaller pieces will fit in a bag. He'll think that you are crazy, but money is money. It's just as well that he does think you crazy, or he'd realise that he could charge you double for such a valueable additive. Be warned though, if a lot of dust, it will be very heavy. I would also suggest that you damp it down before using as the dust can really kick up.

I've not researched it, but from what I remember, ash can be a good additive to soil, but not great. Burning waste can give a quick fix to the soil, but is not long lasting. It make sense to me - a plant absorbs energy from the sun and combined with soil nutrients creates new mass. Burning gives up so much of that stored energy as heat and is wasteful.

Some forest rely on a fire as part of its life cycle. Falling leaves etc enrich the soil over the years, but I suppose that mother nature likes to start afresh sometimes and a fire is nature's way. Some seeds will only germinate after being burned, they lay dormant otherwise.

My experiments with charcoal have been very encouraging to date, but you have to remember that my soil was very poor to start with and has very little organic matter. (also I'm no expert).

I have a few clumps of Holy and sweet basil. They were getting woody with not so many good leaves. I would have pulled them up, but couldn't seem to get new packet seeds to germinate and although the plants were dropping seeds, none would grow. I threw a little charcoal dust down around some of the plants watered (not dug) in. That must have been about 6 weeks ago. The basil treated with charcoal dust has taken on a new lease of life, good strong, vibrant new growth. There are also thousands of new seedlings now, but I can't be sure if that is to do with the time of year or not.

Everywhere that I have introduced a small amount of charcoal, I have seen positive results. Even minute amounts seem to bring almost immediate benefits.

As I empty beds, I'm now digging in organic semi composted matter from the river, charcoal and mature cow dung. For the moment, I've seeded these areas with black beans, not as a crop, but hopefully as green manure.

Also in one area, I've dug in fresh rice husks that have been steeped in compost tea. I've learnt so much from reading these threads and have started to understand the role of nitrogen etc. So it may be considered a bad thing to introduce fresh rice husks, but I'm not so sure. I have used them before to improve drainage and help break up the clay and noted that they are very slow to decompose.

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