"When its done right," is the key phrase. Many other sources of information indicate the biocha needs to be produced in an oxygen free very high heat environment. That may mean that producing biochar requires more energy input, like biofuels, then if gives back. A not cost effective practice.

Same old refrain.

Char is one of the byproducts of combusting wood. Whether or not the energy released from combusting the wood was used efficiently doesn't change the value of the char as a soil additive.

Modern scientists started paying attention to biochar when they started wondering why certain agrarian communities along the rain-drenched Amazon River in S. America had such great soils, when the surrounding soils were devoid of many nutrients (washed out of reach by the heavy rainfall).

It is estimated that these soils were created by humans between 450 BC and AD 950.

Now, DON'T tell me that some guy 2,500 to 9,000 years ago suddenly decided to make a steel container with a few small holes in it, added wood and burned it with minimal oxygen, and then spread it out on his fields. DON'T EVEN GO THERE!!!

The probable reality: These people were hunters/gatherers/planters. They lived in huts. They cooked food. They probably tossed their bones and other debris into the fires to discourage the large predatory cats from coming near the huts. When the fireplaces got full of ashes, they carried it out and spread it onto their fields (just a convenient dumpsite that wasn't too far from safety). They may have also set fire to their fields to keep the weeds down, to make it easy for their planting sticks (no shovels or forks then), and to reduce hiding places for predators.

It may be that low-oxgyen/high-heat pyrolysis is the best way to make biochar, but I think it highly unlikely that it is the ONLY way to make biochar.

As soon as something like this hits the news, myriad people start wracking their brains on how to make money on it. Soon they're bragging that what they make can't be made by Joe Gardener, that he really, REALLY needs to buy this expensive biochar from the Smoke&Mirrors Co.

Adding plain charcoal to your soil beds can only help improve your soil and nutrient-holding capability. Just be sure not to use commerical BBQ charcoal, which contains many unwanted chemicals.

Sue

"Now, DON'T tell me that some guy 2,500 to 9,000 years ago suddenly decided to make a steel container with a few small holes in it, added wood and burned it with minimal oxygen, and then spread it out on his fields. DON'T EVEN GO THERE!!! "

Aw, someone that understands agricultural history. I am glad too see you have posted here, thanks for making some things clear to the viewers.

REally interesting about the soil near the Amazon river.

I just got back from Belize, visiting some organic farms there. They're clearing land the way their Maya ancestors did -- slash and burn the jungle. It doesn't disturb the soil (which has really fragile fertility). And I suppose they're making bio char in the process.

Good -- I'm so glad I don't have to buy one of those steel bio-char makers. I'll just keep spreading ashes and charcoal from my wood burning furnace.

Just be aware that biochar, like ashes, can raise the pH of your soil. With my 5.8 soil, I don't have that problem. But if your soil is near perfect, 6.5 or so, or even higher (alkaline), you'll have to be careful. Do your homework.

Sue

Yes! I started with 5.4 ph, and use the ashes sparingly since all the old timers say not to use too much, and I figure old timers know a thing or two :) Though I know some people who use all their ashes, and things grow fine.

In case anyone wants to build their own gasifier..
I haven't made this, but the plan's auther is a very well-respected guy.

Here is a link that might be useful: biochar gasifier plans

belgianpup,
One thing you may have over looked:
The little green men from Mars took the gasifier back home with them. All they left behind was the pyramids.:-)

Charcoal making is an old tradition. Even in America, the Spanish in the 1600s or 1700s had charcoal-making camps in the mangrove swamps of SW Florida to make charcoal for Havana. They used the old earth-covered mound method, needing no equipment save axes, but preferably with shovels too.

http://www.fao.org/docrep/X5328e/x5328e07.htm

So that would be an example of the worst-case scenario, exploiting a fragile region to make charcoal to be exported for the energy use of some other disinterested place.

A lot people are using plant material from chippers used in activities like power line maintenance and etc.to make biochar. Composting very large quantities of chips is impractical without a front-end loader, itself a very resource-intensive unit. However, once the utility companies or subcontractor has dumped massive piles of fresh wood chips on one's property, the question could be, what is the easiest way to use them that gives the best long-term effect?

Undoubtedly the easiest thing would be to leave it sitting in large piles undisturbed until thermophylic action subsides (a couple of years, possibly), then spread the piles out over areas to be converted to crop production. After another couple of years the ground beneath should be in much better fertility. If used in concert with some stone dusts this could be a very effective use of bulk biomass.

Charcoal is still made in the covered hill pile method. A large pile of chips will take more than 2 years to breakdown. The pile could be covered with earth, as the Spanish did, and made into charcoal. If you were then to add it to a compost pile to allow the fungus, etc to move-in, it would be ready for soil application. Charcoal added to soil without first either microbe or nitrogen charging seems to take a season or more to charge. Uncharged charcoal may actually reduce yield until charged.

If you are going to go at it with anything other than house plants, plan on making your own. At $7 a bag for Cowboy Charcoal you will go broke trying to fill a garden size space.
The best benefit seems to be between 25 and 50% charcoal to soil. 25% being the point that yield really starts to come on and 50% being the point that the worms disappear. Any charcoal is better than no charcoal in my limited experience. Fine powder is preferred to chunks, however, I allow up to 1/4" pieces in my compost due to the impracticality of powdering below that size by hand.

There isn't anything new or unique about adding charcoal to soil. It has/is done in Japan, The Philippines, Africa, South America, to name a few, as a soil amendment. One of the unique parts of South America terra preta is the pottery shard component. I don't see much research or use where this aspect is explored. Having never seen real terra preta I don't know if it is red clay that has been fired or green ware as it has been described by some. I may try to run some tests with broken up pottery shards and charcoal. Does anyone have any information about the pottery type used and percentage of it to the finished mix?

Indeed, converting the top six inches of soil in a good size garden to 25% charcoal is a lot of material. A quarter of a cubic foot of charcoal per square foot of garden space.