To Everyone on the Terra Preta site,
I have been busy this last 2-3 weeks and finally caught up (but not yet digested), all the posts in the last 10 pages. The quality of the posts and the science behind them is fantastic!!! I am sure that Johannes and Bruno are reading (or having a grad student read), this site, and our ideas, after being suitably massaged, will show up in research and papers. They belong to the "publish or perish" world while we do the grunt work and actually get our hands black. (Do you think either of them have a set of "charcoal making" clothes that sit in the work room smelling of campfire?). Of course we wouldn't be where we are without their papers, research, and efforts so I applaud the efforts and they can have some of my ideas (citations please!).
Special kudos to Malcolmf for the recent excellent posts and always to Michaelangelica (that’s a "girl's name isn't it? Excellent post that one!), who is like the glomalin of this site.
Some replies to everyone’s recent work:
To davidgmills, the charcoal cruncher works well on pure charcoal but when I used it on partial biochar it is still not sturdy enough. What I am trying to do on one of my project is take a solid clay soil and add charcoal and SOM to amend the texture of the soil. I am after larger pieces of char and want some of the still wood part and the interface between the charcoal and the wood. My newest charcoal pulverization method is to put it in a box and take my newest invention (3 two by fours nailed together so a 6 x4), and smash the crap out of it. This seems to work well and I do it on a windy day so the soot particles blow away.
To Phillip Small and Malcolmf in reply to your post on page 37 re: types of char and surface properties of the char. See my views above and this article by Johannes Lehmann:
Nutrient availability and leaching in an archaeological .... page 355. Also to davidgmills
Quote:
|
That seems to be what I am observing, as I am not attempting to go to great lengths to pulverize my charcoal.
|
note the particle size comments on p. 355. This gets into the idea that the Amazonian Indians didn't screen their char through a #50 screen but just sort of used it as is. The whole idea is that we don't know what kind of char, what temperature, what size works best but I think we need all of it!
http://www.css.cornell.edu/faculty/l...%20Lehmann.pdf
To Phillip Small very bottom of page 37 on N2O, CO2, and methane emissions form Terra Preta soil. There does seem to be a fair amount of evidence that the charcoal in the soil adsorbs some of the microbial gas emissions. I am currently trying to find articles and evidence that when the charcoal does this it may possibly use the oxygen to oxidize some of the stable charcoal into more labile forms for the microbes to use. Not a lot of information out there and what there is talks around the subject. We do know that charcoal does breakdown but the exact methods are still unknown. If anyone has any information on this please post.
To all on the glomalin/humus ideas. My background is in Physics and via the chemistry that I have had I remember that reactions want to become stable. I think that same principle applies to soil. The high CEC of Terra Preta means that there are lots of ions wanting to go lots of places and bind to lots of sites. That’s one of the things that make TP good for plants. In this process the side chains of the fresh charcoal become oxidized and the charcoal becomes more recalcitrant, and the organic molecules in the soil head towards humus/humin and (I haven't read enough to be sure), possible towards the glomalin that has been mentioned in previous posts.
To all:
In all my research on Terra Preta the one thing that is constant is the charcoal/carbon in the soil. In looking at the physical and chemical properties of carbon the one main fact is that it adsorbs both solid and gaseous compounds. That’s why activated charcoal has so many applications where it is used to purify both water and air.
What the charcoal in the soil does it prevent leaching by water and gas emissions from microbial respiration so that what is in the soil stays in the soil except for plant growth. Of course we do get some leaching and some gas emissions so the process is not perfect.
When we calculate how much carbon we can sequester into the soil we need to take into account the reduction of CO2 emissions that carbon in Terra Preta prevents and the fact that is it then stored as soil organic matter.
So when calculating the carbon sequestration benefits we need to take into account:
1. actual carbon put into the soil
2. reduction of CO2 emissions and increase of SOM (made from carbon/stores carbon)
3. the amount of carbon taking from the atmosphere by increased biomass production due to soil fertility (if charred and put back into the soil)
So for storage of carbon Terra Preta is better than we thought!
Thanks to all,
RB
