Science Forums 2

[Michaelangelica]

I though we had a thread on this? O well
Kurt has given me permission to re-post his Terra preta list post

http://www.scielo.br/scielo.php?pid=S0044-59672004000200004&script=sci_arttext


An interesting bit of information comes out of the above article.

The "cauixi" mentioned is a freshwater sponge. Sponges have 'skeletons'
consisting of tiny needles (spicules) of SiO2----- glass to you. The
photomicrographs quite clearly show these little needle like structures
in the pottery made with cauixi. Embedded in a matrix of clay, these
quite simply operated as glassfiber reinforcement, not unlike the glass
fiber reinforced plastics we often see in things like automotive rear
vision mirrors and other, often injection moulded, plastic parts.

As well, it appears that the clay was not fired to very high
temperatures and therefore not fully vitrified, but the cauixi spicules
would have done a lot to strengthen the resulting pottery quite
substantially. The spicules apparently are also hollow, which would have
added to the porosity of the resultant pottery material, further
enhancing it's ability to soak up nutrients from the foods that were
cooked or stored in the containers made from it. Additionally, silicon
would have been available as a nutrient for plants from them, once the
wee beasties had quarried it out of the pottery.

The cariape was a siliceous ash that was also added to pottery, thereby
increasing the store of silicate in the TP soils, making it available to
plants, via the wee beasties efforts.

Silicone is a micro nutrient of some importance to plants, but really
only recently recognised as such. It increases plant stiffness and also
gives increased disease resistance.

Untempered clay shrinks and distorts considerably in drying and firing
and consequently potters add other materials, such as sand, and in the
case of the relevant amazon area, crushed rock, cauixi and cariape, thus
producing a usable pottery clay that could be effectively made into
vessels. I suppose, eventually someone noticed that garden plots which
contained cast off pottery sherds produced greater yields and as, with
the charcoal, people began adding the sherds on purpose.

If we want to emulate them, we might have to make and burn their
equivalents from clay, tempered with the rock dust that organic growers
use to re-mineralise their soils and perhaps the siliceous ash from
burned grass or bamboo. Perhaps even incorporate ground bones in the
clay. If using a TLUD type charcoal burner the clay blanks could perhaps
be mixed in with the biomass that is to be pyrolised


Kurt

I think zeolite might be amodern day alternative to Amazonian Pottery It seems to do many of the same things that charcoal does in soil
SEE
Zeolite :: Castle Mountain Zeolites - The Finest Zeolites
Zeolite - the mineral and its uses