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Terra Preta in Auroville

One of the biggest patches of Terra Preta is on the high bluffs at the mouth of the Tapajos, near Santarem. First mapped in the 1960s by the late Wim Sombroek, director of the International Soil Reference and Information Center in Wageningen, the Netherlands, the Terra Preta zone is three miles long and half a mile wide, suggesting widespread human habitation - exactly what Orellanana saw. The plateau has never been carefully excavated, but observations by geographers Woods and Joseph McCann of the New School in New York City indicate that it is thick with ceramics. If the agriculture practiced in the lower Tapajos were as intensive as in the most complex cultures in precontact North America, Woods told me, "you'd be talking something capable of supporting about 200 000 to 400 000 people" - making it at the time one of the most densely populated places in the world. Charles C. Mann in 1491. New Revelations of the Americas before Columbus. Chapter Amazonia.

by Bernard Declercq and Deepika
November 2006
Aurobrindavan
Auroville 605101.
India
pebblegardenforest@gmail.com

Terra Preta is a dark coloured, very fertile and apparently self maintaining anthropogenic soil found in large tracts of the Amazon. It seems that conventional research has not yet been able to recreate Terra Preta or to find out how Terra Preta was made by the erstwhile inhabitants of the Amazon basin. We here in “Pebblegarden” have been researching Terra Preta for the last 3 years. At present we are conducting experiments based on reflections and study of the available materials and personal experience.


Raab

Raab is a system of charring biomass used by some tribal communities in India. It consists of making beds of various layers of dry, half-dry and fresh woody and leafy biomass, dung and clay. The thus layered bed is fully sealed with clay and cold fired (burning in reduced conditions). In the resultant residues rice nurseries are started. The tribals affirm that this gives perfect growth to the rice plants. Charcoal bits, ash, even wood vinegar as well as sulfur that may have been absorbed by the clay, would explain the growth enhancing factors of the raab system.

It is likely that the Amazonians practiced a system similar to raab. As it seems, such a system is still practiced in the Amazon today but apparently does not now result in the formation of Terra Preta.

Reflections on the Main Ingredients of Terra Preta

Activated ( ?) Charcoal.

Charcoal definitely seems to be the main ingredient in Terra Preta. Japanese horticulturists and florists have been using charcoal for ages.

Activated carbon can apparently be obtained by pouring water on glowing embers. The steam thus produced creates a tremendous internal surface area (pores) in the charcoal. The impact of rain during the charring of biomass from the forest could have created activated carbon. As it seems that Terra Preta is found near the bluffs of watercourses it could be assumed that water was poured on the charring biomass.

The internal surface of one gram of activated charcoal can vary from 50 m2 to 500 m2, depending on the basic materials, the efficiency and type of process used. Charcoal can thus store a huge quantity of ions and so prevents leaching of nutrients from soil organic matter, an unavoidable fact under tropical high temperature and rain fall conditions.

Treating charcoal with organic vinegar could also create activated carbon. EM used as a bio-activator could eventually also, because of its acidic nature, create activated carbon.



Potshards.

Wherever Terra Preta is found one finds equally potshards. These can make up 8% of the total soil mass. Potshards consists of baked silica clay mixed with various other elements. The dynamic exchange between silica and carbon is supposed to be pivotal for the construction and for the appearance of life on the planet. Research by Jeanne Rousseau has shown that the bio-magnetic exchange between carbon and silica radiates the same wavelength as living molecules. One can infer that an electro magnetic exchange occurs between charcoal and silica-clay.

Research has shown that the ceramic potshards found in Terra Preta contain sand, (amorphous silica) feldspar and iron oxides. Plant extracts from Tubella reticulate, Parnula betesil and from Bignoniacae have also been detected in the kaolinite clay matrix. The abundance of feldspar, coarse igneous rock (Granites, Rhyolites and Quartz) suggests the crushing of rocks found near the banks of the rivers for incorporation in the clay substrate.

These rock elements are most likely paramagnetic. It can thus be inferred that the potshards could be paramagnetic. A soil in which plant growth is perfect is mostly paramagnetic in nature.

The juices from cooking or frying meat, fish or veggies would have penetrated the walls of the cooking vessels which once buried in the soil may have had an influence on soil microbiology. The sooth deposited on the bottoms of the vessels can be considered a form of activated carbon.

In India once a year at harvest festival time, all old cooking pots are broken and discarded. The freshly harvested foods are prepared in new earthen ware. The rationale for this cultural practice for breaking the pots is concern for hygiene as well as a measure to keep the potters going.


Other likely important ingredients

Bonemeal.

There are an estimated 1200 kinds of edible fish in the Amazon rivers. It is thus likely that fish was an important part of the original people’s diet. As Terra Preta is found only close to the ancient village settlements (further away from the ancient villages one finds Terra mulata but not Terra Preta), one can assume that bones and or other fish or animal leftovers or wastes from the kitchen formed a part of the creation of Terra Preta.

The use of animal fats and fish products to create fertile soil has been described in the Vrkshayurveda, and is still used to this date by some farmers in India.


Leaf litter and Bio-inoculants.

Even charcoal, silica and bone meal together may not have been able to produce Terra Preta. The Amazon forest would have provided abundant leaf litter bursting with intense biological life. The leaf litter may have been used as mulch and thus provided a microbial inoculant. Similar practices were used in Holland, Flanders and Germany where farmers of old collected sods from the heather and built extremely fertile soils on poor sands.


Volcanic dust.

It has been stipulated that volcanic dust may have been an essential part in the evolving of Terra Preta. The rivers in the Amazon basin originate in the high lands of the Andes. The Andes is characterized by intensive seismic activity. It seems probably that rock dust or volcanic dust was brought down by the Amazon rivers. During the flooding in the rainy season rock dust laden silt may have settled on the river banks or in the plains. This silt may have been used in the pottery or it may have been used to level up the mounds. In this way the paramagnetic rock and volcano dust could have entered in the process of Terra Preta formation.


Pure water.

The water, rain water or river water would have been very clean and bio-dynamised. This would have prevented the clogging up of the pores of the charcoal. Some of the methods of bio-dynamizing water could be brought into the process of recreating Terra Preta.
EM. is said to prevent the clogging up of the charcoal pores by pollutants.


Air.

Terra Preta is found on mounds often next to water channels. The pottery chards and charcoal would have significantly contributed to the aeration as well as moisture conservation and drainage capacity of Terra Preta. These factors would have been optimally present. These conditions seem present even where the under laying strata have a high clay content.


Additional Remarks.

Terra Preta is found close to the settlements. Residues from the household could have been part of the creation of Terra Preta.

Wood vinegar is known to help plants in their struggle with pathogens. It also seems to have a positive effect on soil fertility.



Experiments with Terra Preta at Pebblegarden.

Pebblegarden is situated on “waste land”. The soil consists of 60 to 80% pebbles or stones (laterite) imbedded in a poor clay. The land was reclaimed by establishing a pioneer vegetation consisting of Acacia coleii var. holosericea and Dodonea viscosa and various weeds. After 3 to 5 years of growth the biomass obtained from the pioneer vegetation is recycled in garden beds. The method of soil building used imitates the manner in which soil is formed and maintained in a forest. The forest floor consists of layers of fallen leaves and twigs and here and there of pats of dung and bird droppings. Termites, ants, earthworms, burrowing animals process and transform the litter into soil …. year after year. For the garden we try to do something similar, using very thin alternate layers of dry leaves/biomass and soil to create beds and heaps. The process is further refined and enriched in numerous creative ways using neighborhood and home resources, recycling crop residues, kitchen waste etc.

After 1 or 2 years of cultivation, the garden beds are reshaped to form double lines of heaps and valleys. The heaps consist of 20 to 25 liters of soil. The valleys between the heaps are filled up with woody materials, partly with wood bark and partly with dry twigs, up to the level of the heaps. In the heaps a mixture of charcoal and post shards soaked for 2 days in extended EM, together with small amounts of dolomite (to correct low Ph.) and bone meal is incorporated. The heaps and valleys are covered with a leaf mulch so that again the appearance of a bed is formed.

The observation plots with Terra Preta show a clear and positive correlation to the method applied, though as yet we have not been able to incorporate any paramagnetic rock dust. So far we have not yet followed any strict formal investigation.


Future Research Projections.

Charcoal, paramagnetic rock powder in clay, as a source of silica, seem to be the pivot on which research in Terra Preta must proceed. As there is hardly any soil at pebblegarden the practice of raab is not a real option. Therefore we intend to construct an Iwasaki kiln which would provide charcoal and wood vinegar. We have started trials with local available (acid) granite dust and marble powder. Granite dust mixed with marble powder and clay in equal proportions has shown a positive paramagnetic value. The intention is to mix these ingredients, form small slabs of about 25 sq. cm and 1 cm. thickness and insert these in the Iwasaki kiln together with the woody material for charring. This could have an effect equal to that of the pottery shards found in Terra Preta. The temperature in the kiln would be sufficient to get the slabs baked. The wood vinegar could be used to treat the charcoal and or as a soil fertility enhancer. Charcoal, the paramagnetic briquettes and bone meal will be incorporated in the garden soil heaps.

Though the water used for irrigation in pebblegarden is neutral and uncontaminated we still need to look into appropriate ways to bio-dynamize it. This could either happen through vortex or magnetization. Flow forms and other forms of dynamization do not look practical under the present conditions.

Proper evaluation of “Terra Preta” plots versus control and computing of data will be undertaken with the next set of trials.

We welcome your suggestions or comments. Support for the continuation of the research is needed. Your contributions will be most welcome.

Thank you Amazonians of lore for the treasure you have left behind and for showing us a way out and into the future.