[Terrapreta] Terra Preta & Soil Quality

[Janice Thies]

Dear All,

I am extremely heartened by the very positive response to the idea of using 
of biochar in agriculture and horticulture and appreciate your desires to 
put it to immediate beneficial use in these systems.

My name is Janice Thies.  I am a soil microbial ecologist.  I have been 
working with Johannes Lehmann at Cornell University for the past 6 years on 
various aspects of terra preta (microbial ecology in its natural state) and 
agrichar (how microbial populations respond to adding biochar to soil). It 
took us three years to convince the National Science Foundation that we 
were on to something here and to obtain funding for some of the basic 
research that is necessary for us to provide the data needed to answer your 
questions with confidence. Hence, we are several years behind where we 
could have been if funding had been available earlier.  Even now, we 
continue to seek support for doing the types of tests many of you are most 
interested in. The results of our NSF funded research are just now being 
published or written up, but we are still a long way from being able to 
answer everything.

Currently, there are 10 research laboratories around the world that are 
testing char made from bamboo that was prepared at 5 different temperatures 
in the range we believe is likely to provide char that will be most 
beneficial for both plant production and C sequestration purposes.  Rob 
Flannigan prepared the char in China and has engaged us all to do a wide 
range of testing on it.  So, we should have some news about what 
temperature range might be best reasonably soon, but it is still early days.

One of the reasons that Dr. Lehmann recommends caution in the use of 
biochar can be seen in the paper recently published by Christoph Steiner et 
al., mentioned in previous messages. He did get excellent plant growth 
responses to adding biochar - as long as mineral fertilizer was also used. 
When you look at plant growth in the biochar only treatment, growth was 
worse than doing nothing at all (check plots). In the nutrient-poor and 
highly leached soils of the tropics, the added biochar likely bound 
whatever nutrients were present in the soil solution and these became 
unavailable for plant uptake. These results should make you cautious as 
well. How fertile a soil needs to be for biochar not to reduce plant growth 
or exactly how much fertilizer and/or compost should be added to be sure 
there is good, sustained release of nutrients, will likely vary soil to 
soil and we simply do not have these data available at present to make 
proper recommendations.  So, keep this in mind as you do your own trials 
with your own soils or mixes.  Try to follow good design practices for your 
trials, with replicates, so that you can judge for yourself what amount and 
type of biochar works best in combination with what amounts and types of 
fertilizers or composts you use (depending on the philosophy behind your 
cultural practices).

As to the 'wee beasties' or 'critters' as I like to call them, we have made 
progress on this front over the last several years.  Brendan O'Neill and 
Julie Grossman in my laboratory, Sui Mai Tsai, our Brazilian collaborator 
at CENA and the University of Sao Paulo, and Biqing Liang, and many others 
in Johannes Lehmann's laboratory have been characterizing microbial 
populations in three different terra preta soils and comparing these to the 
adjacent, unmodified soils near by to them. Brendan found that populations 
of culturable bacteria and fungi are higher in the terra preta soils, as 
compared to the unmodified soils, in all cases.  Yet, Biqing found that the 
respiratory activity of these populations is lower (see Liang et al., 
2006), even when fresh organic matter is added. This alone means that the 
turnover of organic matter is slower in the terra preta soils - suggesting 
that the presence of black C in the terra pretas  is helping to stabilize 
labile organic matter and is itself not turning over in the short 
term.  All good news for C sequestration.  However, since the respiratory 
activity is lower (slower decomposition), this may lead to slower release 
of other mineral nutrient associated with the fresh organic inputs. In some 
circumstances this is a good thing (maintaining nutrient release over the 
growing season), in other circumstances (more immobilization), perhaps 
not.  We need more work on this to understand the implications of these 
results more fully.

Julie Grossman, Brendan O'Neill, Lauren McPhillips and Dr. Tsai have all 
been working on the molecular ecology of these soils along with me.  So 
far, what we know is that both bacterial and fungal communities differ 
strongly between the terra pretas and the unmodified soils, but that the 
populations are similar between the terra preta soils. These results are 
both interesting and encouraging.  First, that the terra preta soils 
(sampled from sites many kilometers apart) are more similar to each other 
than to their closest unmodified soil (sampled within 500 m) tells us that 
the conditions in the terra pretas encourage the colonization of these 
soils by similar groups of organisms that are adapted them. Our group has 
been working on cloning and sequencing both isolates from the terra preta 
soils and DNA extracted directly from them. A number of bacteria that were 
isolated only from the terra preta soils are related to the actinomycetes, 
but have not yet been described yet and are not very closely related to 
other sequences of known organisms in the public genetic databases. This is 
also very interesting.  Some of you will know that actinomycetes have many 
unusual metabolic capabilities and can degrade a very wide range of 
substrates.  Also, many are thermophilic and play important roles in the 
composting process.  We have yet to fully characterize these organisms, but 
are optimistic that in time we can make some recommendations about what 
organisms or combinations of organisms might make a good inoculant for 
container-based biochar use.  Two papers describing these results are in 
their final editing stages and will be submitted for publication in the 
journal 'Microbial Ecology' within the next few weeks.  So, keep an eye out 
for them in several months time.

I want to add a word of caution about getting too excited about glomalin. 
Another of my students, Daniel Clune, has been working on this topic and 
his work suggests that the glycoprotein referred to as 'glomalin' in the 
literature - operationally defined as the protein extractable in a citrate 
buffer with repeated autoclaving - is not what it has been purported to be. 
First, the proteins extractable by this method are from a wide range of 
sources, not just arbuscular mycorrhizal fungi.  Second, it has a shorter 
turnover time than has been suggested.  Third, in a test with hundreds of 
samples taken from field trials varying in age from 7 to 12 to 34 years, 
its relationship with aggregate stability is suggestive at best. Dan's work 
is also being written up right now and should also be submitted for 
publication soon.

Some field trials with bamboo char have been conducted in China, with very 
positive results.  Look for upcoming papers from Dr. Zheng of the Bamboo 
Institute in Hangzhou.  Another student in my laboratory, Hongyan Jin, is 
working with the soils from this experiment to characterize the abundance, 
activity and diversity of the soil bacteria and archaea. Her first results 
will be presented at the upcoming conference on Agrichar to be held in 
Terrigal, NSW, Australia, at the end of April/beginning of May this year. 
Please be sure to see her poster should you attend this conference.

Lastly, from my personal gardening experiences, I use spent charcoal from 
the filters of the 14 aquaria I maintain for my viewing pleasure. I combine 
it as about 5% of my mix with 65% peat moss, 10% vermicompost (from my worm 
bin in my basement where I compost all my household kitchen waste - aged 
and stabilized, not fresh!), 5-10% leaf mulch (composted on my leafy 
property in NY), 5-7% perlite to increase drainage, decrease bulk density 
and improve water retention and percolation, and some bone meal and blood 
meal (to taste :-) ).  This makes an excellent potting mix for my indoor 
'forest'.  I am very much still playing around with this.

I hope this very long posting helps those of you feeling frustrated and 
wanting answers.  Many labs are working on many fronts, but it is early 
days and we are trying to answer some fundamental questions first and then 
use the information to guide our field tests and recommendations.

I hope to meet some of you at the Agrichar Conference (see details at the 
conference website) http://www.iaiconference.org/images/IAI_brochure_5.pdf
The Cornell work and that of many of our colleagues in Brazil, China, the 
US, Australia and elsewhere will be presented, along with that of many 
others actively working on agrichar production and use around the world.

Good luck with your own testing and kind regards,

Janice Thies - jet25 at cornell.edu
719 Bradfield Hall, Ithaca, NY 14853

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