Message #114905

[Bianca]

Pedology



Terra Preta is defined as a type of latosol, having a carbon content ranging from high to very high
(more than 13-14% organic matter) in its A horizon, but without hydromorphic characteristics.

The composition of Terra preta presents important variants. For instance, the gardens close to dwell-
ings received more nutrients than fields farther away.

The variations in Amazonian dark earths prevent from establishing a clear separation line on whether they were intentionally created for soil improvement or whether the lightest variants are a by-product of habitation.

The varied features of the dark earths throughout the Amazon Basin suggest the existence of an extensive ancient native civilization dating back 500 to 2500 years bp.

Terra preta's capacity to increase its own volume – thus to sequester more carbon – was 'discovered' by pedologist William I. Woods of Southern Illinois University Edwardsville.  This central mystery of
Terra preta, is actively studied by many researchers from various disciplines.

The processes responsible for the formation of Terra preta soils are:



Incorporation of wood charcoal

Incorporation of organic matter and of nutrients

Role of micro-organisms and animals in the soil