[Terrapreta] char & vascular systems

[Richard Haard]

Interpreting my soil analysis series has been interesting. I just  
received analysis from my spring tests and because of the costs I am  
omitting the fall test series ($315 each set of 28). Last year we  
conducted 2 test series, spring and fall.

Most striking is the lack of nitrogen as nitrate in fall and  
reappearance  in spring. This indicates to me the biological role of  
biomass in preventing leaching of this soluble mineral.  As soon I  
finish my spring planting work load I am going to attempt some  
analysis of this set and compare to last year. I am not sure though  
whether my simple set of analysis and growth observations is going to  
answer this question of char role in soil. It is helping us though to  
understand the usefulness of our current soil management program,  
composting and fertilization by comparing different treatments in a  
block study. We have never studied our soils so intensively and  
learning how fertility varies in adjacent blocks has been a revelation  
and a factor that confounds analysis.

I think by extending our study for a number of years, as long as we  
can do it, will give us the most useful information. With analysis  
that we do not have access because of our position as farmers and not  
university researchers we are not able to do the tests to identify  
nitrogen fixation, to study soil respiration or microbial composition  
much less the more frequent and more detailed chemical analysis.

This brings me back to a more scholarly approach to try to understand  
more fully what has already been published by the scientific community.



On Jun 7, 2008, at 10:51 PM, Mark Ludlow wrote:

> In all fairness, I hope I didn't imply that I thought that habitat
> opportunity has no role. However, it's difficult to imagine that this
> macroscopic (in dimensional terms) activity is the primary driver  
> for the
> goodness of char. The macroporous structure, while desirable, may be
> overrated

I would not agree with your terminology 'macroporous' as some charcoal/ 
cell structures only admit bacteria because of size while others are  
large enough for certain fungi but not others and invertebrates, and  
so on .
In addition the inorganic environment of charcoal serves as a  
selective cultural enrichment for chemoautotrophs and mycorrhizal  
symbionts and their interactive communities of other organisms. In the  
literature difference is noted in respiration response of original   
terra preta soils to TP nova indicating to me the result of time and  
the ecological balance that occurs in the microbial population after  
many years in a black carbon rich soil. Species profiles cannot be  
done but DNA profiling is a useful tool. What does this information  
indicate?

This all points in my opinion - the primary reason for function of  
terra preta is biological not physical chemical properties of soil. If  
the reverse were the case then would not clay colloids and their  
surface active function mask or replace the function of charcoal or  
black carbon in soil. ??

Back to my own problems conducting and interpreting my own tests I  
really do not know what is the 'background level' of black carbon in  
my sandy loam test soils. This takes expensive and difficult tests and  
as is known from published results as much as 30% of soil organic  
matter in some soils can be represented as black carbon.

At our site we have found  native artifacts from archaic period, up to  
8,000 to 10,000 years bp and western washington was probably uncoved  
from the last glacial period about 15,000 years ago. Much can happen  
during this period of time. I can walk around our fields in the winter  
and pick up tiny pieces of charcoal anywhere, then also assuming there  
is powder unseen just what role/significance does this already play?

Rich

> compared to advantages conferred by having large, surface-reactive
> areas--at least in the advantage of regulating soil fertility.
>
> Mark
>
>
> Richard Haard wrote:
>> I am not quite sure what you are getting at here Kurt?
>>
>> In the case of algae the only difference is the lack of vascular
>> system. The algae are diverse and cellular in nature that range from
>> filamentous to complex tissues in plants attaining as much as 100  
>> feet
>> length.
>>
>> Are you in agreement with mark that charcoal function is at the micro
>> level and habitat opportunity has no role.
> No, I'm not. I believe that the vascular nature of wood charcoal and
> particularly of hardwood charcoal is very important to it's role in  
> TP.
> So, as far as TP is concerned the habitat opportunity is most  
> important.
> And along with the habitat opportunity goes the large surface area  
> that
> is inherent in wood charcoals vascular structure, which is important  
> for
> bacterial activity. Now, to a large extent other fibrous biomass would
> have similar porosity, while amorphous biomass would likely have less.
> Just how this integrates with the alleged good TP results from fecal
> charcoal, I have no idea.
>
>
> Kurt
>