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Amazonian dark earths and Caboclo subsistence on the middle Madeira River, Brazil

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posted on 2023-06-07, 15:20 authored by James Angus Fraser
This thesis examines the relationship between Amazonian Dark Earths (ADE) and Caboclo subsistence on the Middle Madeira River, Brazil. ADE are fertile anthropogenic (man-made) soils formed through practices of burning and waste disposal by pre-Columbian Amerindian populations. “Caboclo” is a social category that refers to the people of diverse origins that form the majority of the contemporary rural population of Brazilian Amazonia. Bitter manioc fields (roças) and homegardens (sítios) are the principal forms of Caboclo subsistence cultivation on ADE on the Middle Madeira River. Multi-sited ethnography shows that differences in historical ecology at both local and regional scales either enable or constrain Caboclo subsistence cultivation on ADE. At communities located on long-term landholdings with a history of egalitarian land-tenure and multi-generational kinship there is a rich body of local knowledge and practice relating to the cultivation of ADE. Interviews with 249 farmers in six localities demonstrate that bitter manioc cultivation in fertile soils (floodplain and ADE) tends to be characterised by intensive swidden systems with smaller fields, shorter fallows, and a predominance of what locals refer to as “weak” (low starch fast maturing) landraces. Bitter manioc cultivation in infertile soils (Oxisols and Ultisols) is characterised by more extensive shifting cultivation systems with larger fields, longer fallows and a predominance of what locals refer to as “strong” (high starch slow maturing) landraces. Interviews with 63 households at 16 communities show that homegardens on ADE combine the most common species of homegardens on Oxisols and in the Floodplain, with other species that occur most frequently on ADE. Homegardens on ADE exhibit significantly higher culturally salient species diversity when compared to homegardens on the other types of soil. Collectively, bitter manioc fields and homegardens constitute cultivated landscapes that show diverging agrobiodiversity on different soils, the outcome of an interplay between soil affordances, Caboclo agency and plant responses over time. These findings provide a springboard for some conclusions concerning the relationship between ADE and agriculture in the pre-Columbian period, drawing on what is known from the historical and archaeological record.


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