Navegando por Assunto "Terra Preta"

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Acesso aberto (Open Access)
lndicadores de estabilidade da matéria orgânica em terras pretas nos sítios arqueológicos Jabuti e Jacarequara (Pará)
(Universidade Federal do Pará, 2015-09-02) SENA, Luciana Freitas de; KERN, Dirse Clara; http://lattes.cnpq.br/8351785832221386; 8351785832221386; LEMOS, Vanda Porpino; http://lattes.cnpq.br/1829861620854008; 1829861620854008
Environmental conditions in the Amazon region favor the weathering and decomposition of soil organic matter, making it depleted in nutrients and difficult agricultural use. But in the same region, areas that have been modified by human action preterit, known as Terra Preta Archaeological (TPA), have different properties, among which stands out the high stability of soil organic matter (SOM) that in some research it is attributed to interactions between the MOS and other soil constituents such as pyrogenic carbon and minerals from the soil. In this study were selected two archaeological sites in the state of Pará, the Jabuti, the cemetery housing type, located in the city of Bragança, and the Jacarequara, the sambaqui type, located in Barcarena, in order to assess the stability of organic matter TPA from soil extracted solutions (depths 30 and 80 cm) and own soil (collected during the implementation of extractors in December 2013) in areas of TPA and vicinity. The characterization of soil solutions was conducted in the period between March and June 2013, based on the macroscopic properties and the chemical indicators: dissolved carbon concentrations (organic, inorganic and total), determined by the combustion method; pH, Eh and conductivity. The SOM stability assessments in the solid phases of the TPA and surrounding areas (ADJ) were based on textural verification of soil chemical indicators (pH, organic carbon concentrations and Ca, K, P, Na, and Mg) and biological represented by the microbial biomass, determined by the method of irradiation / extraction and expressed in terms of carbon (Cbm) and nitrogen (Nbm). The results of the soil solutions showed that two sites in the pH values are higher in depth (80 cm), and at the site Jacarequara values were determined for this parameter up to 7.2, while the site Jabuti pH results do not exceed the value 6. The maximum values of Eh (mV), conductivity (μs) and dissolved organic carbon (mg L-1) in place Jacarequara, 30 cm deep were respectively +201 mV, 427 µs e 13 mg L-1 and in the area adjacent to this site, at the same depth the highest values were +128 mV, 72 µs e 23 mg L-1 for the same parameters. At the Jabuti site and its ADJ, in 30 cm deep, the respective maximum values of the same areas were Eh +108 mV and +96 mV; conductivity 138.87µs and 59.85µs, dissolved organic carbon 12 mg L-1 and 21.08 mg L-1. Comparing the areas of TPA and their ADJ, the data Eh and dissolved organic carbon refer to more stable components in soil areas of solutions of TPA, owing to the more oxidizing values and smaller dissolved organic carbon concentrations, the results conductivity, which is an indicator of the concentration of ions is higher in the TPA reporting the increased availability of nutrients. In both sites, soils presented sandy texture, both in the areas of TPA as the ADJ, the latter being more sandy. In the soil Jacarequara site and its ADJ in the range of 20 to 30 cm deep, the following values were obtained respectively: 119.82 g kg-1 and 20.34 g kg-1 for SOM; pHH2O equal to 6.8 and 4.9; 183 mg/dm3 and 5 mg/dm3 P (available); 39 mg/dm3 and 29 mg/dm3 K (exchangeable); 14.8 cmolc/dm3 and 0.7 cmolc/dm3 Ca (exchangeable); 0.1 cmolc/dm3 and 1.7 cmolc/dm3 Al (exchangeable), 181.26 μg g-1 and 88.74 μg g-1 of Cbm and 3.27 mg kg-1 and 1.91 mg kg-1 Nbm. In the soil of Jabuti site, the determined values were: 83.66 g kg-1 of MOS, pHH2O equal to 4.4; 55 mg/dm3 P (available); 59 mg/dm3 K (exchangeable); 0.3 cmolc/dm3 Ca (exchangeable); 4 cmolc/dm3 of Al (exchangeable); 92.56 mg kg-1 of Cbm and 1.41 mg kg-1 Nbm; in the area adjacent to this site, the values were: 13.13 g kg-1 of MOS, pHH2O equal to 4.6; 4 mg/dm3 P (available); 29 mg dm3 K (exchangeable); 0.3 cmolc/dm3 Ca (exchangeable); 1 cmolc/dm3 Al (exchangeable), 27.54 mg kg-1 of Cbm and 0.96 mg kg-1 Nbm. As well as other archaeological sites with TPA, Jacarequara and the Jabuti had significantly higher levels of nutrients compared to surrounding areas, with the exception of Ca element in Jabuti. In the sites, carbonaceous particles were investigated, showing no intrinsic results pyrogenic carbon. In areas of TPA, the results obtained from the soil analysis indicated positive correlation between the microbial biomass, organic matter and nutrients, which can be associated with better quality of the soil in these areas compared their ADJ, consistently with the data highlighted in the soil solutions. Comparing the two sites, the results indicate that the SOM in Jacarequara site shows more stable constituents.
Acesso aberto (Open Access)
Mineralogia e geoquímica de terra preta arqueológica para identificação de padrão ocupacional pré-histórico no vale do Baixo rio Amazonas (Juruti, Pará)
(Universidade Federal do Pará, 2011-12-16) COSTA, Jucilene Amorim; KERN, Dirse Clara; http://lattes.cnpq.br/8351785832221386; 8351785832221386; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302; 1639498384851302
In the Amazon basin, the soils of a large number of sites have been modified by ancient pottery-making peoples. These soils, known as Indian Dark Earth or Archeological Dark Earth (ADE), generally cover relatively small areas, but in some cases, may extend to dozens of hectares. Some of these ADE sites are surrounded by soils known as Terra Mulata (TMA). The ADEs are dark in color, and have relatively high levels of Ca, Mg, P, Mn, Zn, Cu and organic C, ceramic fragments (CF), and charcoal. By contrast, while the TMA are relatively dark, they lack ceramic fragments, and have lower levels of Ca, Mg, P, Mn, Zn, Cu, and organic C than the ADE, even though these levels are generally higher than those found in adjacent soils or Latosol (Oxisols). Along the right bank of the lower Amazon River, at Juruti, in the Brazilian state of Pará, ample areas of ADE were found surrounded by equally extensive tracts of TMA the during archeological rescue operation that preceded the construction of the ALCOA bauxite extraction and processing plant. These locations, known to be archeological sites rich in ceramic fragments and organic matter, were investigated with the aim of understanding the possible inter-relationships between the ADE and TMA soils and the specific role of the prehistoric occupation of these soils, and the determination of the pattern of occupation, and the time scale of the occupation of the Amazon basin. Samples of soil and CF were obtained from the two archeological sites with ADE and TMA selected for this study. The soil and CF samples were collected from pedological profiles within a standardized 60 m x 120 m grid, representative of the ADE, TMA and adjacent soils. The mineralogy of the samples was then analyzed using XRD, SEM-EDS and optical microscopy, and their chemistry (including major and trace elements) was determined using ICP-OES and ICP-MS. In addition to these chemical and mineralogical analyses, the CF were examined archeologically with a binocular lens, and dated using thermoluminescence. The fragments of charcoal were dated using the radiocarbon (C14) method using the AMS technique. The results show that the soils are made up essentially of quartz and kaolinite, with illite + muscovite, goethite + hematite, and anatase in smaller proportions. These minerals reflect the Al2O3-Fe2O3-TiO2 association that has been interpreted as the signature of soils derived from the ferrous-aluminous crust of lateritic profiles, equivalent to the adjacent soils. While ADE and TMA are relatively similar in their mineralogical and chemical composition, they are partly different in the content of each mineral and in their concentrations of the chemical elements. On the other hand, apatite, Al phosphate, and cristobalite are practically exclusive to the ADE, being found only rarely in the TMA, and entirely absent from the Latosol. The apatite and Al phosphate represent the principal sources of the high levels of Ca and P. The ADE and TMA soils are also characterized by the high levels of organic matter, and can be identified by the P2O5-CaO-MgO-Na2O-K2O-Zn-Cu-Mn-Ba-Sr-Li-Ni association, which can be interpreted as an indicator of human activity. The geochemical maps of these elements and the distribution of the CF permitted the delimitation of the ADE zones as representing areas of permanent human occupation, defined by the higher concentrations. Seven patches of darker, enriched soil were grouped in two principal nuclei, separated by corridors of soils equivalent to adjacent area (Al2O3-Fe2O3-TiO2-Cr-Y-V-Zr geochemical association). These patches, characterized by an abundance of ceramic fragments, were interpreted as being the sites of ancient settlements. The TMA lies in a wide, continuous belt parallel to the river, between the ADE and the adjacent soil, and is interpreted as an area of campsites or the locations of agricultural activities. The stylistic characteristics and the chronological order of these fragments indicate that the occupation of the area is represented primarily by two distinct ceramic phases, the older Pocó phase, and the more recent Konduri phase. The thermoluminescence and C14 dating indicate that these pottery-making peoples probably occupied the region between 140 B.C. and the 13th century, with the ADE being formed subsequently. The ceramic fragments represent the remains of both ceremonial vessels and everyday artifacts. Their mineralogical and chemical composition is similar to that of the clay used by the region’s present-day potters. The differences are restricted to the high levels of phosphorus (between 1% and 4% P2O5) found in the fragments in the form of amorphous Al and Fe phosphates, which are found at crustal levels in the present-day clay. This reinforces the conclusion that their origin was related to the use of the ceramic vessels, especially for cooking food. From the mineralogical and chemical similarities between the CF of distinct cultures and ages, it is possible to infer that the raw material used by the ancient settlers of this region were invariably sourced from the same deposits or geological formations, beginning more than 2,000 years ago, and which are still used by the region’s present inhabitants. Overall, then, the evidence indicates that the deposits of ADE and TMA soils in the area of Juruti, which extend for more than 350 hectares, are a consequence of extensive and intense prehistoric human activities, which imposed significant transformations on the original local soils. The hot and humid climatic conditions, and the dense forest cover were fundamental to the formation of these soils.
Acesso aberto (Open Access)
Transferência química na cadeia solo-mandioca-cabelo humano na região de Caxiuanã (Estado do Pará) e sua importância ambiental
(Universidade Federal do Pará, 2008-05-02) CARMO, Marciléia Silva; KERN, Dirse Clara; http://lattes.cnpq.br/8351785832221386; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302; https://orcid.org/0000-0002-0134-0432
In the area of Caxiuanã, State of Pará, stands out the occurrence of several sites with soils type Amazon Dark Earth (TPA). They are dark soils characterized by the presence of ceramic fragments and high concentrations of Ca, Mg, Mn, P, Zn and C, when compared with other soils of Amazonia. They are fertile soils used for subsistence agriculture, mainly the cassava (Manihot esculenta Crantz). In attempt to know the physical, chemical, mineralogical and fertility characteristics of these soils and the interrelations between these and the adjacent areas (AD), cultivated or not with cassava, as well as the capacity of adsorption of nutrients and possible potentially toxic metals by the cassava and the transfer to the human body using hair analysis (mineralogram) the present work was developed. Aiming these results, sites were selected with TPA with and without cassava roçado (TPA/CR and TPA/SR) and adjacent areas also with or without cassava roçado (AD/CR and AD/SR). Samples of soils and cassava including the roots (tubers), leaves and tucupi were collected in the ranches with AD and without AD. Samples of human hair were collected of the riverine population that consumes the cassava of the studied roçados, here denominated: TPA family, those who live in TPA/CR areas; and AD family, those who live in AD/CR areas. The soil samples were submitted to grain size (humid-via), mineralogical (XRD), and chemical (ICP-MS of major, minor and trace elements) besides the fertility analysis. In the cassava samples (roots and leaves) the macronutrients (P, K, Ca, Mg, S), micronutrients (Fe, Mn, Zn, Co, B, Cu, Mo and Ni), non-nutrients and the toxic elements (Pb, Cd, Ce, Sn, Sc, Cr, Zr, Sr, Ba, Al, Na, Hg, Se and As) were determinate by ICP-MS. In hair samples, the essential (S, Ca, Zn, Mg, Cu, Se, Sr, Mn, B, I, Cr, V, Co and Mo), additional (P, Fe, Na and K) and toxic elements (Pb, Bi, Al, Ba, Hg, Ni, Sn, Sb, As, Cd, Ag, U and Th) were also determinate by ICP-MS, what characterize the mineralogram, and correspond to most of elements analyzed in the soils and cassava. The soils are mainly composed by quartz, kaolinite and hematite + goethite, and accessories as anatase, muscovite / illite and zircon. This way they are constituted mainly by SiO2 and Al2O3, besides Fe2O3, TiO2, K2O and Zr. The tendency to the decrease of Al2O3 and Fe2O3 concentrations and the increase of SiO2 concentrations and lots of ignition from B-horizons to A-horizons is really according to the classic evolution of the soils under tropical climate with tropical forest covering. The studied ADEs present pedologic profile similar to other TPAs with high contents of organic carbon and to other TPAs in A-horizons. The concentrations of total Ca, Mg, Mn, Zn and P are relatively high when compared to the Amazonian soils, one of the great distinctions among TPA soil and the adjacent area, and compared to the TPA soils of Caxiuanã and other areas of Amazonia. However, the available P contents are lower, due to the continuous use of TPA in agriculture of roçado. Therefore, as expected, it is probable that the use of TPA in agriculture of roçado is progressively exhausting the nutrient reserves, but in less intensity than the common soils of Amazonia. The chemical analyses of the cassava show that the macronutrients and micronutrients are mainly concentrated in the leaves, and the concentrations do not depend on the soil in which it was cultivated, TPA or AD. In the root (pellicle, skin and pulp) with lower contents than in the leaves, the analyzed elements are mainly concentrated in the pellicle. The non-nutrient and toxic elements found in the cassava are mainly concentrated in the pellicles, followed by the leaves, skin and pulp. The pulp -the part of the cassava used in the human diet - therefore is impoverished in macro and micronutrients, as well as in non-nutrient and toxic elements. The tucupi - the liquid phase - presents low concentrations of the analyzed elements (nutrients, non-nutrients and toxic), while the solid extract is especially composed by C, K, Mg, P and Ca, besides Na, as oxalates and phosphates. The transfer factor (TF) from the soils to the cassava cultivated in TPA and AD areas was elevated in relation to macronutrients (K, Ca, Mg and P), mainly in the leaves, and medium to micronutrients (Fe, Mn, Zn, Co, Mo and Ni) being higher in the cassava cultivated in AD areas due to the lower content of those elements in AD soils and also to the fact that the cassava absorbs only the substances necessary to the basic physiologic function. This way, it’s evident why TPA, much enriched in nutrients, is more appropriate for the agriculture in continuous cultivation of cassava. The hair mineralogram of the researched families of Caxiuanã shows that the variance of the concentrations of the essential and additional elements is higher in TPA than in AD family, while the average concentrations were similar in the two families. On the other hand, the concentrations of toxic elements are relatively higher in the AD family, mainly Pb and Al. The essential and additional elements contents are below the reference values while the toxic elements Al, Pb, Sb and Ba, are above the range of normal values. The concentrations of the essential and additional elements are cumulative with the age. The concentrations of Fe, Al and Bi are higher in the children, therefore susceptible to toxic elements (Al and Bi). According to the sex, the essential, additional and toxic elements are more concentrate in women. The concentrations of essential and additional elements, mainly Mg, Zn, Ca, Sr, Se, Co and P are lower, and of toxic elements Ni, Pb, Sb and As are higher in smokers. This suggests that the habit of smoking possibly inhibits the absorption of most of the elements essential to the capillary formation. Probably due to the possible coexistence with smokers, high concentrations of Ni, Pb, Sb and As were found in among several children, being considered passive smokers. Among the identified geochemical associations, Hg-Sb-Ag-Zn-Bi-Pb-Se-Cd association reflects the smokers. The obtained data of this work and its discussion show that the TPA soils are in fact fertile and the adjacent areas (AD) are relatively impoverished, and the TPA soils enriched in nutrients allow the continuous cultivation of cassava that absorbs from the soil only the necessary for its physiologic function. The pulp of the cassava leaves - more consumed by the man, impoverished in macro and micronutrients - contributes to the poor diet of the riverine population of Caxiuanã. The chemical composition of the cassava didn't show dependence with the soil type (TPA or AD). The chemical composition of the hair of the population of Caxiuanã that feed on cassava cultivated in TPA and AD areas confirms the poor alimentary diet. The mineralogram also shows that the principal external factor of contamination is the tobacco, and perhaps the kitchen aluminum utensils. So the mineralogram is used as a valuable tool to evaluate environmental impacts related to the human health. Therefore, the problems related to the human health in the area of Caxiuanã are in part due to the poor alimentary diet and the habit of smoking, because the soils don't present evidences of anthropic impacts neither of geogenic anomalies.