Estudo dos métodos de extração e comportamento do fósforo na Terra Preta Arqueológica da mesorregião central do estado do Amazonas

Abstract

The Archaeological Black Aarth (ABE) are Antrossolos known for being the most fertile soils of the Amazon. One of the features of the ABE is the presence of archaeological ceramic fragments as well as high amounts of phosphorus and calcium. These facts are used as an important record of the Amazon occupation by pre-Columbian civilizations. This paper presents results on phosphorus extraction methods ABE eight sites of the State of Amazonas Central Mesoregion. Samples of ABE and ceramic fragments were collected in eight archaeological sites. Phosphorus were obtained by acid digestion, fractionation by Chang and Jackson method and the extraction solutions Mehlich-1, Mehlich-3, Bray-1 and Olsen. All phosphorous concentrations were determined by UV-vis spectroscopy using the method of ammonium molybdate at the wavelength of 885 nm. The results showed that Mehlich-1, the extraction solution which overestimates the match in some quantities ABE sites. The Mehlich- 3 and Bray-1 showed similar extraction capacity. Olsen was extracted single extractant that smaller amounts of phosphorus in all ABE sites. The fractionation indicated that most phosphorus medium is connected to the input of calcium, phosphorus explaining the overestimation extracted with Mehlich-1. The archaeological ceramics shown to be a potential source for phosphorus replacement for ABE. Overall, the results of this study allow to recommend the use of Mehlich-3 extraction solution for the estimated phosphorus availability in ABE.