[Terrapreta] Numerical data

[MMBTUPR at aol.com]

          from          Lewis L Smith

Reading these posts, recalls my experience with Dr. Alex G. Alexander's 
world-famous "energy cane/energy grass" project at the Agricultural Experiment 
Station in Lajas PR, 1976-81.

It seems to me that things are getting a bit complicated, mainly because we 
have a lot of "actors" either already on or entering and exiting the "stage", 
during the course of a year. These include not only the existing soil plus the 
terra preta but fungi, detached leaves, fertilizers, insects, microbes, 
nutrients, plants, rain water, stray molecules et cetera. So the number of possible 
interactions becomes quite large and difficult to deal with in writing.

At some point, it might be convenient, to make a spreadsheet. The columns 
would be points in time, t sub zero ....   t sub n, where "zero" and "n" are the 
beginning and the end of the "cycle", however one wants to define this.

There would be several lines for each participant in the process, grouped by 
materials which carry over from one cycle to another indefinitely, inputs 
waiting to enter process or storage, materials in process, materials in storage 
and outputs, plus additional lines to record "transactions", that is, movement 
from one line to another.

Storage might be broken down between intracellular and extracellular. And 
example of the latter is fungi who "come to rest" on some part of the terra preta 
structure but which are not chemically incorporated into it, as shown in some 
of the very clear photos which have been linked to this site.

Once one "got things organized", it should be easier to account for and to 
establish the corresponding biochemical reactions for, each "transaction" in a 
systematic manner

The foregoing leads to several observations   >

[1]     We must be more specific as to what kind of carbon compounds we are 
talking about, when we say the magic words "terra preta". From the posts, it 
seems to me that there a quite a few different kinds, that they differ, if not 
biochemically at least in terms the kind of "visitors" which they attract" and 
that they can give quite different   agronomic results, depending not only on 
the foregoing but on the "management system" applied to them.

[2]      From reading these posts as an outsider [ an energy economist with 
lots of bioenergy experience ] I believe that the concept of "storage" has not 
been given enough attention. For example, regardless of the management system, 
one must do things to make the cane plant grow in physical volume during "the 
dead season". As it grows, it produces two important sugars among others, 
fructose and glucose, which in turn help to sustain the growth process. 

In the "sugar cane" management system, one tries to harvest well outside any 
rainy period and if using irrigation water, one cuts it off about three weeks 
before the harvest. At this point, much of the fructose and glucose turns into 
sucrose, which is the plant's way of storing energy. This increase in sucrose 
meets the objective of the traditional sugar-cane management system, which is 
to optimize the ratio by weight of sucrose to millable stalk.   

[ In the energy cane management system developed by Dr. Alexander, the 
objective was quite different, to optimize by weight fiber per acre. However, with 
many varieties, it often substantially increased sucrose per acre as well, to 
everyone's surprise. 

In fact, Dr. Alexander originally started out to increase sugar production 
per acre, changing the goal of the sugarcane management system for economic 
reasons. The potential for increasing fiber production as a source of energy was 
brought to his attention by the then president of the U of Puerto Rico, the 
late Arturo Morales-Carrión, a historian no less ! Dr. Alexander "grabbed the 
ball, ran with it" and got a million dollar grant from DOE to study energy cane 
and energy grasses. Sometimes, history "turns on a dime". ]

[ Incidentally, when the sucrose arrives at one's stomach, it immediately 
dissociates into fructose and glucose. So I have never understood the people who 
claim that sugar is "bad" while fructose and glucose are "good". They are all 
fattening ! ]

[3]      We should pay more attention to the different ways in which one can 
manage a given set of inputs and soil conditions. Sometimes a difference in 
system can make a big difference in results, as Dr. Alexander found out. What we 
define as "terra preta" and how we make it may not always be "the whole 
story".

[ Soil scientists please forgive any errors. I am recalling from many years 
ago ! ]

Cordially.   ###


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