Data/hora: 21/09/2024 15:21:38

Biblioteca(s): 	Embrapa Solos.	
Data corrente: 	07/07/2021	
Data da última atualização: 	13/10/2021	
Autoria: 	PINHEIRO JUNIOR, C. R.; PEREIRA, M. G.; AZEVEDO, A. C. de; HUYSSTEEN, C. van; ANJOS, L. H. C. dos; FONTANA, A.; SILVA NETO, E. C. da; VIEIRA, J. N.; SANTOS, T. G.	
Afiliação: 	CARLOS ROBERTO PINHEIRO JUNIOR, UFRRJ; MARCOS GERVASIO PEREIRA, UFRRJ; ANTÔNIO CARLOS DE AZEVEDO, USP/ESALQ; CORNIE VAN HUYSSTEEN, UNIVERSITY OF THE FREE STATE; LÚCIA HELENA CUNHA DOS ANJOS, UFRRJ; ADEMIR FONTANA, CNPS; EDUARDO CARVALHO DA SILVA NETO, UFRRJ; JONAS NUNES VIEIRA, UFRRJ; THAIRIS GOMES SANTOS, USP/ESALQ.	
Título: 	Genesis and classification of carbonate soils in the State of Rio de Janeiro, Brazil.	
Ano de publicação: 	2021	
Fonte/Imprenta: 	Journal of South American Earth Sciences, v. 108, 103183, Jun. 2021.	
DOI: 	https://doi.org/10.1016/j.jsames.2021.103183	
Idioma: 	Inglês	
Conteúdo: 	Carbonate rocks occur in Brazil under diverse climatic and environmental conditions, and therefore are of great importance for pedological studies. The northwest region of the State of Rio de Janeiro, Brazil, is composed of calc-silicate rocks and marbles that occur under tropical climate with a long period of water deficit, which provides conditions for peculiar pedogenesis. The objective of this study was to characterize the attributes of soils formed from carbonate materials and to understand the role of the main factors and processes in pedogenesis, as well as to provide information to the WRB (World Reference Base for Soil Resources) to improve carbonate soils classification. A toposequence was selected in the municipality of Italva, RJ, Brazil, with six profiles being described and sampled. All profiles presented median CaCO3 equivalent contents, high base saturation with the predominance of Ca+2 and Mg+2, and high activity clay. The absence of effervescence and low CaO/MgO ratio obtained by acid digestion suggest the dolomitic nature of the carbonates. Pedogenic carbonates were amorphous, since no XRD peaks were found. The high Mg+2 concentration provided by the parent material increases the dispersion of clays and favors clay illuviation, which is manifested in the micromorphology through a large amount of clay infillings and coatings. Four profiles on the highest part of the landscape were classified as Kastanozems (Mollisols), the footslope profile as Fluvisol (Inceptisol), and the toeslope profile as Vertisol. The mineralogy of the Vertisol's clay fraction was predominantly composed of kaolinite interstratified with 2:1 phyllosilicates, mainly illite. Acid digestion can complete the analysis of the CaCO3 equivalent content by quantifying CaO and MgO concentration in fine earth samples, presenting the potential to distinguish the Dolomitic/Calcaric qualifiers. The recognition of Dolomitic/Calcaric qualifiers for the Kastanozem reference soil groups is suggested, considering that the carbonate present in the calcic horizon may be diverse.	
Palavras-Chave: 	Dolomitic; Pedogenesis; WRB.	
Thesagro: 	Classificação do Solo; Gênese do Solo.	
Thesaurus Nal: 	Carbonates; Kastanozems; Soil classification.	
Categoria do assunto: 	P Recursos Naturais, Ciências Ambientais e da Terra	
Registro original: 	Embrapa Solos (CNPS)	
Exemplares: 	CNPS - (20694-1) - UPC - AP - DD -  -  -  - DIS