Re biochar. I think it needs to be remembered that virtually all woodlands need to burn at some stage in their life. In the 'fynbos' of my local flora, it is about once every 15 years. Much of the life cycle is adapted to this burning - seeds buried underground by ants only germinate when the water reaching them contains chemicals signalling a fire has passed.
Deciduous forests also need to burn regularly. One of the 'problems' is that the leaf trash becomes so thick that decomposition starts to go anaerobic, and when that happens, acid is generated. Conifer leaves too are very acidic - years ago I was party to a study of acid rain on some land planted commercially with conifers. We found that far more acid was picked up once the rain reached the ground than fell from the sky, all generated from decomposition of the conifer needles. Another study with which I was associated looked at forests in northern Germany. Historically, there were layers of char in the soil about every 100 years. These ceased in modern times - mankind didn't like forest fires too close at hand. However, the net result was growing acidity in the soil, a weakening of the timber's defenses and signs of waldsterben - basically sheer old age because the natural burn had not occurred. Then I reflected that ash is alkaline. In combustion, you drive off acidic CO2, and are left with an alkaline waste (usually rich in potash and phosphorus). Also, during combustion you generate quite a lot of nitrogen oxides, and these return to earth with rain as another essential nutrient. That is partly why land regularly recovers rapidly after fire - or why pastoralists regularly set fire to stimulate nutrient-rich young shoots that the grazing animals emjoy. So yes, biochar is generally beneficial to soil. It is usually there naturally. I hope this contribution helps to understand what biochar is all about. Philip Lloyd -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 26 November 2010 10:00 To: [email protected] Subject: Stoves Digest, Vol 3, Issue 27 Send Stoves mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org or, via email, send a message with subject or body 'help' to [email protected] You can reach the person managing the list at [email protected] When replying, please edit your Subject line so it is more specific than "Re: Contents of Stoves digest..." Today's Topics: 1. Re: Biochar Projects for Science Students (Jeff Davis) 2. Re: Biochar Projects for Science Students (steve) 3. Re: Biochar Projects for Science Students (Crispin Pemberton-Pigott) 4. Re: Biochar Projects for Science Students (Andrew C. Parker) ---------------------------------------------------------------------- Message: 1 Date: Thu, 25 Nov 2010 21:56:51 -0500 From: Jeff Davis <[email protected]> To: Discussion of biomass cooking stoves <[email protected]> Subject: Re: [Stoves] Biochar Projects for Science Students Message-ID: <1290740211.1428.58.ca...@jeff-laptop> Content-Type: text/plain; charset="UTF-8" Dear Kevin and Crispin, I doubt that all the damage done to the soil from forest fires can be blamed on charred tree roots, maybe some, maybe not. In regards to grass fires how much of the charcoal gets washed away, how much is ash and how much grass char works into the soil. In the long run would the grass land been better off without the grass fire? Does the grassland fires do as much damage to the soil as forest fires do to the forest soil? Do these two items accurately represent biochar? If we look hard enough we can find just about anything in the soil from lost pocket change to beer cans... Sloppy science? People, we're talking about thousands of years here.... This is the time for a group of real soil scientists, that are not bought and paid for by a concern, to determine whether there could be any long term problems down the road. Lets not find out 75 years from now. Frankly I'm not qualified, the engineers are not qualified, the chemists are not qualified, the hobbyists are not qualified and to say that charcoal is inert so therefore no problem is reckless and irresponsible. We are on the verge of making policies on a global scale and someone has to be the bad guy and ask "if biochar persists in the soil for thousands of years and it has not been added to the soil on a global level in any meaningful way will there be any long term problems down the road?" The benefits of biochar are meaningless at this point. We need to make sure that there will not be any problems down the road. Personally I hope it works out OK. BUT shame on me if I don't speak up! Best regards, Jeff -- ________________________________________________ www.puffergas.com Sent from any port in the storm via Acer netbook & Ubuntu Remix. ------------------------------ Message: 2 Date: Fri, 26 Nov 2010 08:23:53 GMT From: "steve" <[email protected]> To: Discussion of biomass cooking stoves <[email protected]> Subject: Re: [Stoves] Biochar Projects for Science Students Message-ID: <[email protected]> Content-Type: text/plain; charset="iso-8859-1" > > The benefits of biochar are meaningless at this point. We need to make > sure that there will not be any problems down the road. Personally I > hope it works out OK. BUT shame on me if I don't speak up! I was under the impression that bio-char had been used as a soil improved in South America from the earliest civilisations there. Surely that must count. Steve ------------------------------ Message: 3 Date: Fri, 26 Nov 2010 23:54:16 +0800 From: "Crispin Pemberton-Pigott" <[email protected]> To: "'Discussion of biomass cooking stoves'" <[email protected]> Subject: Re: [Stoves] Biochar Projects for Science Students Message-ID: <[email protected]> Content-Type: text/plain; charset="us-ascii" Wise words, Jeff. It would be interesting to know if the terra preta soils were artificially created or were the consequence of cyclical burning in a rotation (slash and burn). It is hard to know if the roots will burn well. When I lived in Nigeria one of the things people had difficulty understanding was this idea of a forest burning - inconceivable! If the roots burn underground for some distance like they do in Canada, then there is a lot of char produced by slash-and-burn agriculture. That does not require premeditation and intent, even if the consequences were beneficial. It is well known that the fertility in the jungle is in the biomass above the ground. That means just about any available fertility is not below the ground, or it will have been absorbed and turned into plant material. The question is: will a biome with most of its fertility below the ground benefit from biochar? This is a really interesting question. The answer is bound to be complex. The char produced by stoves will have to be characterised to see how it compares with that added as amendments. Nothing I have seen written so far attempts to look at that so I guess it is relatively unexplored. Frank can you do any assessments of the contents of the char you are producing in your tiny tube retort? Is there any reason to believe stove char is a) variable, b) different, c) homogeneous? Regards Crispin ------------------------------ Message: 4 Date: Fri, 26 Nov 2010 11:05:47 -0700 From: "Andrew C. Parker" <[email protected]> To: "'Discussion of biomass cooking stoves'" <[email protected]> Subject: Re: [Stoves] Biochar Projects for Science Students Message-ID: <op.vmshvxz6uoo...@user-8ezctxe031> Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes Crispin and All, In regards to "accidental" terra preta, I am including a post I made to wattsupwithat.com last January: "Many years ago, I read a book on swithen agriculture in the upper amazon basin and the eastern woodlands of the US. The main point of the book was that these ecosystems supported many more times the current populations before european agricultural and land tenure patterns were established. The vast majority of land cleared in the late 1700?s and early 1800?s in the eastern woodlands has now reverted back to forest. The thin forest soils were quickly depleted after clearing and burning, forcing families to move West for better opportunities. Swithen agriculture used a strictly managed rotation system that maximized the resources of the forest ecosystem, giving the native populations a sustained abundance of agricultural goods, forest products and wild game. (It is theorised that the devastating epidemics that followed the first european explorers left remaining populations unable to maintain forest management, which may explain why Hernando De Soto?s descriptions of the american south differed substantially from what later explorers and settlers found.) I have not read much of the terra preta literature but the description of the charcoal being found in thin layers would seem to support the idea that the native inhabitants used a rotating swithen agriculture that could still be found in some areas of the amazon basin thirty years ago. Nothing magic or mysterious. Now, I wonder if terra preta soils can be found in the eastern US?" I still wonder about terra preta in the US. Any soil scientists out there that can answer the question? Andrew Parker On Fri, 26 Nov 2010 08:54:16 -0700, Crispin Pemberton-Pigott <[email protected]> wrote: > It would be interesting to know if the terra preta soils were > artificially created or were the consequence of cyclical burning in a > rotation (slash and burn). ------------------------------ _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address Stoves mailing list to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/ [email protected] http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org End of Stoves Digest, Vol 3, Issue 27 ************************************* _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address Stoves mailing list to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/ [email protected] http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
