ABSTRACT
Archaeological dark earth (TPA) are areas of soil with an anthropogenic A horizon of high organic carbon content, a dark colour and high fertility. Little is known about the physical characteristics of these soils, especially with respect to structure and pore space. The hypothesis of this study is that the distribution of structural and textural pore space in TPA soils is similar, regardless of texture. The aim therefore was to evaluate the pore space of TPA soils of different textural classes by employing a double-exponential model. Four archaeological sites of varying grain size were sampled in the towns of Melgaço and Igarapé-Açu, in the State of Pará, Brazil. Disturbed and undisturbed soil samples were collected at a depth of 0.10 m. Soil texture ranged from sandy loam to sandy clay loam. The double-exponential equation made it possible to differentiate between textural and structural pores of the TPA sites. Despite the variation in texture, the TPA sites did not differ as to textural porosity, with only site 1 (S1) showing greater structural pore space. The ratio of textural to structural pores did not influence soil density, however, the textural pores were positively related to the organic matter content of the soil.
Key words:
Amazonian Dark Earth; Soil water retention; Organic matter
