No till gardening

[GaryD]

Hi mornings,

I must confess that Arachdog's mention of terra preta soils got me rushing off on a google about bio char where the more I read, the more excited I became.

They get kinda emotional, a little like aquaponics people who are so intent upon growing fish.

More heresy, hey.........someone start gathering the firewood! We'll create a little bio-char and rid ourselves of another heretic at the same time.

While we're readying the fire, can you talk a bit more about the variables to which you referred?

During my meanderings on the subject, I see that Dr Tim Flannery (Australia's leading climate control scientist) has got on board with the bio char thing.


Gary

[mornings]

More heresy, hey.........someone start gathering the firewood! We'll create a little bio-char and rid ourselves of another heretic at the same time.

Gary,

Hmmm . . . I never thought about them making biochar out of heretics . . . I better be careful what I say.

. . . can you talk a bit more about the variables to which you referred?

Two things come to mind: 1) I normally get about a month or so of really hot, humid weather in the late summer -- that is when most of the damage is done, the burning off of carbon in the soil. Coincidentally, that just hasn't happened in the last couple years -- little hot humid weather and plenty of rain. That would mean, possibly, that the carbon (humus) just didn't burn up like it usually does. 2) The beds were not in a regular rotation after I applied the biochar, but in cover crops. Both covers add nitrogen and the rye puts lot of organic matter into the soil, and without growing any heavy or even medium feeders, that might have allowed carbon to build up and increase CEC. I say "might" because I don't know.

But I figure hot and humid weather will come back and I am in regular rotations now. I've records on the growing in these beds for over 20 years, so at some point I should be able to judge how well the biochar did.

One of the things about the biochar is that it doesn't show up in the soil analysis. It is essentially inert. That makes sense. If it were active it would not still be in the soil 4000 years later.

Undoubtedly, the biochar does have a benefit to the soil and maybe the environment. But there are just lots of things we don't know about it. In fact, I don't think they really understand all the know about the original terra preta. Unfortunately, the folks who first did this didn't leave any record of what they were doing.

The most popular voodoo is that the biochar creates habitat for various microorganisms that keep/increase organic matter/biomass in the soils, thus increasing the CEC, increasing nutrient holding capacity. I don't know, but if this is true it may take some time to prove it out. If there were definitive knowledge about using terra preta, you would be able read about it (If you find any, let me know). Most of what is out there is just speculation and the equivalent of old wives tales.

It is likely that biochar will help most in poor soils in warmer climes. In Indiana, Iowa and Ohio muck soils, e.g., there just isn't much one could do to make the soils better by adding CEC and it doesn't get hot enough long enough to do damage. Their biggest problem is a lack of calcium and drainage.

IF biochar does have a benefit in my soils, I intend to build a device that I can heat my house in the winter and make biochar at the same time. I'd grow more vegetables and be politically correct! Gonna use a "rocket stove" . . . but that is, as they say, is another story.

m

[arachdog]

Thanks morning. Very interesting read. I think you could be right about it taking some time for it to properly develop. Also the value of it in a tropical climate with torrential rain is probably always going to be greater than in a temperate climate. It could still be valuable though and would probably be very suitable to a lot of farmers that use large quantities of water like cotton, or maybe rice.
So when applied the charcoal did you break your no till vow and mix it in a bit or did you just sprinkle it on the surface?

[GaryD]

It is likely that biochar will help most in poor soils in warmer climes.

That may explain some of the excitement about the subject in Australia. Our soils are ancient and 150 years of European farming methodology has really knocked them around in some parts of the country.