[Stoves] Edinburgh biochar

[sylva at iname.com]

>    So far I have only been able to listen to the Lehmann tape (no questioning) and the follow-up panel (all questions).   I was surprised mainly by the arguments/questions by quite a few seemingly favoring compost, or combustion or tree burial.  This is a new non-biochar-enthusiast group perhaps.  Too little time for adequate rebuttals/discussions.

AJH I don't understand some of the terms the soil scietists and chemist use, It was mostly technical papers and the gist was there have been few negative effects, only one mention oof ethylene which Alex falgged up as a problem.

Things like reduction of N2O emmission seem only to happen if the soil is saturated. Many features of the initial behaviour of biochar ( such as "primming" of the release of CO2 from soil organic carbon are put down to abiotic causes, I.e. they are straigh chemical effects of putting a high pH carbonate contining subsance into an acid environment.

There was a misleading presentation about life of logs in soil as it only studued first 30cms of soil rather than deep burial, deep burial is likely to persist for hundres of years.

The interesting points were the life of the labile or non fixed carbon portions of the char ( tars etc) this varied for 2-500 years but the fixed char potentially thousands of years. There will be interesting studies to do with how theres labile portions contribute to the biochar effect ( they are touted as food for bugs) compared with the long term benefit of fixed carbon. Also the business of how high a temperature to char at, essentially the fixed carbon of a woodchar sample is always ~15% no matter what the pyrolysis temperature and it will be less for feedstocks with low lignin. As you rightly point out one eminent person did question the use of biochar when its energyvalue was lost as an opportunity cost, IMO in a society that still digs up fossil fuels he is right.

Now here is the nub for me, all talk of rewarding the substance farmers over the whole globe for sequestrating the emmissions of us rich few are gone. Talks of offsets and carbon trading was missing, chiefly because this was a gathering of soil scientists.

The closing message from Lehmann is pertinent, he now says biochar must have proven agronomic benefits to be successful, the implication is then sequestration will be the net resuslt. I still see photosynthesis as being the only viable means of fixing CO2 and biochar the means of intervening in the carbon cycle and storing it.

The delegate who stated that we would reach a global population of 9 billion and a temperature rise of 4C was not doubted.

There was a talk on hydrothermal carbonisation and it is apparent that the results ( the lady coined the term hydrochar)  are qite differnt from biochar and probably not a means to sequestration.

There was little at the conference to upset my friend Kevin C and noting to worry people that don't see a problem with athropologically enhanced CO2 levels in the atmosphere

Steve, I shall travel back after an appointment on Scheihallion shortly so will probably be too late and will not pick up mail again till Saturday.

Please forgive the typos, I am not used to this small screen
AJH