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34 results

Carbon Stocks and Pools in Relation to the Texture of Kaolinitic Soils from the Brazilian East Coast

João Bosco Vasconcellos Gomes, Carlos Alberto Silva, Tamara Letícia de Azevedo Ferreira, Mozart Martins Ferreira, Alberto Vasconcellos Inda, Nilton Curi


ABSTRACT: Extremely kaolinitic soils of Tertiary age elevations on the Brazilian east coast present a wide range of texture, which is recognized as one of the main factors controlling the soil organic matter contents. This study aimed to investigate the organic C storage of different compartments of kaolinitic soils. The studied soils had a wide particle size gradient, were under native forest vegetation, and located on Brazil’s eastern coast (Coruripe – CF, Umbaúba – UF, Nova Viçosa – VF, Sooretama […]

Geochemical Signature of Amazon Tropical Rainforest Soils

José João Lelis Leal de Souza, Maurício Paulo Ferreira Fontes, Robert Gilkes, Liovando Marciano da Costa, Teogenes Senna de Oliveira


ABSTRACT: Evaluating soil geochemical diversity in the Amazon Basin has been a challenge largely because most study sites have been at the edge of the basin and it is difficult to get samples in such a region. Here we show that even among the most weathered soils, physicochemical soil properties express lithology. Our results are based on topsoil samples collected from different locations in minimally disturbed areas in the state of Amazonas, Brazil. Soil properties were measured using methods which […]

Phosphorus Forms in Sediments as Indicators of Anthropic Pressures in an Agricultural Catchment in Southern Brazil

Tales Tiecher, Ricardo Bergamo Schenato, Maria Alice Santanna, Laurent Caner, Danilo Rheinheimer dos Santos


ABSTRACT Phosphorus (P) fractionation is a suitable procedure to ascertain P lability in sediments and is able to distinguish sources of P under different soil management practices in a catchment. Brazil is the second largest producer and the largest exporter of tobacco in the world. Inadequate management of cultivated areas exposes the soil to erosion processes, accelerating the transfer of sediment and P to water bodies, which leads to eutrophication. We evaluated the P forms in suspended sediments collected at […]

Impact of an Alkaline Solution on the Chemistry, Mineralogy, and Sorption Properties of a Typic Rhodudult Soil

Jaqueline Alves de Almeida Calábria, Stela Dalva Santos Cota, Ana Cláudia Queiroz Ladeira


Abstract The preferred option for disposal of short-lived low and intermediate level radioactive wastes is a near surface disposal facility in which soil is one of the barriers that avoid radionuclide migration outside the controlled area. For construction of that kind of facility, concrete is widely used, and its interaction with water induces its degradation, resulting in a high pH solution. The alkaline solution may affect the near-field environment of radioactive waste repositories, including the soil, promoting mineralogical alterations that […]

Effect of Mineral Nitrogen on Transfer of 13C-Carbon from Eucalyptus Harvest Residue Components to Soil Organic Matter Fractions

Michelle de Sales Moreira Demolinari, Rodrigo Nogueira de Sousa, Ivo Ribeiro da Silva, Rafael da Silva Teixeira, Júlio César Lima Neves, Gilberto de Oliveira Mendes


ABSTRACT The amount of harvest residues retained in Eucalyptus plantations strongly influences soil organic matter (SOM), but the efficiency of conversion to SOM may vary according to the type of residue. This study evaluated the recovery of C from Eucalyptus residue components – leaves, bark, branches, roots, and a mix of all residues – in different SOM fractions with or without mineral-N supplementation (200 mg kg-1 of N). Variation in natural 13C abundance was used to trace the destination of […]

Organic Matter Stocks and the Interactions of Humic Substances with Metals in Araucaria Moist Forest Soil with Humic and Histic Horizons

Daniel Hanke, Deborah Pinheiro Dick


ABSTRACT Soils with humic and histic horizons in tropical and subtropical ecosystems play an important role in determining the atmospheric C stock and its stabilization, climate regulation, water holding capacity, and environmental filtering, due to the different functions of soil organic matter (SOM). However, the processes and mechanisms that regulate SOM dynamics in these soils are not clear. The objectives of this study were: i) determine the C and N stocks and ii) investigate the SOM chemical fractions and their […]

Aggregate Stability in Soil with Humic and Histic Horizons in a Toposequence under Araucaria Forest

Daniel Hanke, Deborah Pinheiro Dick


ABSTRACT Aggregate stability is one of the most important factors in soil conservation and maintenance of soil environmental functions. The objective of this study was to investigate the aggregate stability mechanisms related to chemical composition of organic matter in soil profiles with humic and histic horizons in a toposequence under Araucaria moist forest in southern Brazil. The soils sampled were classified as Humic Hapludox (highest position), Fluvaquentic Humaquepts (lowest slope position), and Typic Haplosaprists (floodplain). The C and N contents […]

Microwave Acid Extraction to Analyze K and Mg Reserves in the Clay Fraction of Soils

Araína Hulmann Batista, Vander Freitas Melo, Robert Gilkes


ABSTRACT: Extraction of K and Mg with boiling 1 mol L-1 HNO3 in an open system for predicting K and Mg uptake by plants is a method of low reproducibility. The aim of this study was to compare the extraction capacity of different acid methods relative to hydrofluoric acid extraction for K and Mg. A further objective was to develop a chemical extraction method using a closed system (microwave) for nonexchangeable and structural forms of these nutrients in order to […]

Comparing Methods for Extracting Heavy Metals from Histosols for Establishing Quality Reference Values

Erica Souto Abreu Lima, Nelson Moura Brasil do Amaral, Daniel Vidal Pérez, Izabella Bezerra Coutinho


ABSTRACT The diversity of methods for heavy metal extraction from soils complicates comparison of results used by environmental agencies to establish quality reference values. The aim of this study was to evaluate three soil digestion methods regarding the solubilizing capacity of Ba, Cr, Cu, Fe, Mn, Ni, Pb and Zn, and to propose a standard method to establish Quality Reference Values (QRVs) for Brazilian Histosols. Twenty soil samples were selected to evaluate the USEPA 3051, USEPA 3051A and Aqua Regia […]

Carbon and Nitrogen Stocks and Humic Fractions in Brazilian Organosols

Gustavo Souza Valladares, Marcos Gervasio Pereira, Vinícius de Melo Benites, Lúcia Helena Cunha dos Anjos, Adierson Gilvani Ebeling, Roni Fernandes Guareschi


ABSTRACT Despite limited geographic expression of Organosols in Brazil, their high carbon storage capacity and natural environmental vulnerability justifies further studies on C and N stocks in these soils and their relationship to the nature of organic matter. Evaluation of physical and chemical properties of organic soils and their ability to store C is important so as to develop sustainable management practices for their preservation. The objectives of the study were to measure the total organic carbon stock (OCst), total […]

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