Rajan
In compost there are stable and active fractions http://www.springerlink.com/content/7pm80230072r4116/ In biochar its all very stable. The mix of active fraction and stable fractions is better because the active fraction feeds soil microorganisms which liberate soil nutrients. Of course the very best is a mix of biochar and compost to soils where an amazing soil is created quickly, while it takes much longer to build up with compost only. The main problem I have with biochar is that you simply can't afford to bury carbon as it has too high an economic value that can't be recovered by carbon credits at present prices. From an energetic standpoint it doesn't as effectively use the fuel resource as other ways to deliver heat in cooking applications. As the world continues to run down its wood fuel resources, biomass resdiues will continually increase in value and make biochar processes less economically viable and make other processes such as I mentioned earlier more viable. Biochar has its advantages but biomass fuel savings is not one of them. Roger -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Wednesday, September 15, 2010 11:44 AM To: Roger Samson Cc: stoves Subject: Re: [Stoves] The Biochar myth..another stovers myth Dear Roger, ----- Original Message ----- From: "Roger Samson" <[email protected]> To: "'Discussion of biomass cooking stoves'" <[email protected]>; <[email protected]> Sent: Wednesday, 15 September, 2010 07:47 PM Subject: RE: [Stoves] The Biochar myth..another stovers myth > > Yes Crispin is correct that is another stovers myth is that biochar saves > trees. Energy lost in carbon buried is carbon borrowed from another > source. Biochar can be used as fuel or soil nutrient or some other purpose according to somebody's choice. "Saving of trees" happens when we "stop cutting the trees". Personally, I am very much against unreasonable cutting of trees. My main points are as follows: 1. Use residues for fuel instead of cutting trees. 2. If charcoal from residues is used as soil nutrient, the process is carbon-negative. 3. If charcoal from residues is burnt as fuel, the process is carbon neutral. 4. If somebody is cutting trees for fuel ( without proper replacement ), the process is carbon-positive - contributing to global warming, etc. This is precisely what is happening today - see how forests disappear. > > It's the lignin fraction in biomass (trees, grasses roots etc) that is not > readily decomposed when added to soils. Lignin can be considered the most > important relatively stable C fraction in plants that is not readily > decompsoed. Phytoliths in grasses are also an important carbon source for > forming soils. The grassland soils of the world (chernozems etc) are > formed > as a result of years of deposition of phytoliths We can grow grasses and > pelletize them and create both improved soils and lots of clean bunring > high > yielding fuel. > To my knowledge, carbon from biochar remains in the soil as carbon for much longer time - compared to carbon present in compost ( which gets converted into CO2 ). Please correct me if I am wrong. Best Regards, Rajan _______________________________________________ Stoves mailing list [email protected] http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org http://stoves.bioenergylists.org http://info.bioenergylists.org UNSUBSCRIBE HERE; http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org
