Monday, January 26, 2009
Pottery shards, Terra Preta, Soil
The charcoal and pottery shards are the two most common by-products of human habitats.
Source of Charcoal and Pottery shards in parts of rural India.
| Aspect | Charcoal | Pottery Shards / baked soil |
| Cook stoves | Charcoal | Cooking pottery utensils |
| Water storage | | Pots |
| Slash and burn | Charcoal (up to 50%) | Baked earth |
| Seasonal crop residue burning | Charcoal | Baked earth |
| Slash and burn of forest areas / bushes intentional | Charcoal | Baked earth |
| Accidental forest fires | Charcoal | Baked earth |
| Rural enterprises | | |
| - Potters Kiln | Charcoal | Broken pottery shards |
| - Black smiths place | Charcoal | |
| - Hotels | Charcoal | |
| Community kitchens (Schools / temples / etc.) | Charcoal | |
| Rituals / Cultural | | |
| - Ceremonial pottery used for all cultural occasions and festivals | | Pottery shards |
| - Yagnas | Charcoal | Pots |
| - Cultural Bonfires – during Holi / Sankranti festivals / etc. | Charcoal | Pots |
| - Cremation grounds | Charcoal | Pots |
| - Housing | | Roof tiles replacement |
| Toys | | Clay toys and Pots |
At least some charcoal / biochar along with ash was contributed by the people living in habitations in the past (see table above). The availability of the quantity of such by-product, ingenious use, management and development are the aspects still to be discovered. If charcoal / pottery shards did not occur in certain areas in spite of human settlements existence, than there must be some reason yet to be discovered. But both charcoal and pottery existence as a result of human activities was beyond history, so there is no reason why these things are not seen..
The fired pottery made up of clay is most popular. Still the poor people in rural villages in parts of India cook in the clay pots. The pots used for drinking water collection is most common, even today millions of pots are produced and used all over India every year, the usage would be more especially during summers. The evaporation of the water from the fine pores of the pot cool the water inside the pot. The temperature would be at least 5 deg centigrade less than the surrounding air temp. The cooling effects would be very high under less relative humidity conditions. The roofs made up of clay tiles also provide cool shelter, and very much useful in the tropics where temperatures are very high during summers. For majority of the main festivals pots or pottery items are used. From Birth to death, for all important occasions pottery items are used.
The water tanks / ponds silt is used for pottery. The organic carbon content of the clay collected from such water tanks / ponds has around 0.9%. Such clay is mixed with a little ash+charcoal powder from the kilns.
And sometimes for fire resistance quartz sand is also used along with ash. The availability of ponds / tanks and a stream for sand helps in development of pottery.
The pieces of broken pots are thrown in a Farm Yard Manure pit. During manure spreading pottery shards also reach the fields. With time the size of the pottery shards reduces due to breaking. Ultimately over years the pottery shards spread. It was observed that the density of occurrence of pottery shards varies from field to field.
Bricks Pieces made up of clay were also seen in the fields although in few numbers. This appearance could be due to two reasons. In the fields where density of the bricks were high, the possibility is that there could have been a bricks making kiln in the fields, secondly the chance is that the bricks from the demolished houses enter into the fields as dumps.
Traditional Practices - sustainability of agriculture