Data/hora: 10/06/2024 18:50:49

Biblioteca(s): 	Embrapa Cerrados; Embrapa Solos.	
Data corrente: 	11/02/1993	
Data da última atualização: 	20/09/2016	
Autoria: 	MACEDO, J.	
Afiliação: 	JAMIL MACEDO, CPAC.	
Título: 	Morphology, mineralogy, and genesis of a hydrosequence of oxisols in Brazil.	
Ano de publicação: 	1986	
Fonte/Imprenta: 	1986.	
Páginas: 	73 p.	
Idioma: 	Inglês	
Notas: 	Thesis (Master of Science) -- Cornell University, Ithaca.	
Conteúdo: 	Research was conducted to establish the genetic relationship between soil color patterns and natural drainage characteristics in a hydrosequence of Oxisols formed in Tertiary/Quaternary sediments of the Cerrado (Savanna) Region in the Central Plateau of Brazil. The soils classify as Acrustoxs and Pilinthaquoxs in Soil Taxonomy and as Dark-Red Latosols, Red-Yellow Latosols, and Hydromorphic Laterite in the Brazilian classification scheme. In addition to standard soil classification analyses, x-ray diffraction and sodium citrate-bicarbonate-dithionite extractions were used to determine soil mineralogy. Precipitation was recorded and weekly positions of the water table at sampling sites were measured in observation wells for a period of one year. Kaolinite, gibbsite, quartz and iron oxides are the dominat minerals in all sites. Relative amounts of theses minerals show similar desilication trends with depth at all sites in the hydrosequence. Well drained soils with water tables below 3 meters had reddish hues (2.5 YR or 5 YR) reflecting and oxidizing environment and a co-dominant hematite and goethite iron mineralogy. The upper organic rich solum in sites with seasonally high water tables (<2m) had yellowish hues (10 YR or 7.5 YR) and dominantly goethitic iron mineralogy. In the deeper perennially saturated zones of all profiles the matrix color has reddish hues (2.5 YR or 10R) and a dominantly hematitic iron mineralogy. Stratigraphic, geomorphic, and pedogenic evidence supports the hypothesis that the observed soil colors and corresponding differences in iron mineralogy are a pedogenic adjustment to change in the hydrology of these soils brought about by landscape evolution.	
Palavras-Chave: 	Brasil; Dark-red latosol; Distrito Federal; Latossolo vermelho-amarelo; Latossolo vermelho-escuro; Morfologia do solo; Oxisolo; Planaltina; Red-yellow latossol; Soil genesis.	
Thesagro: 	Cerrado; Gênese do Solo; Mineralogia; Solo.	
Thesaurus Nal: 	Brazil; Ferralsols; mineralogy; soil morphological features; soil sequences.	
Categoria do assunto: 	--
P Recursos Naturais, Ciências Ambientais e da Terra	
Registro original: 	Embrapa Cerrados (CPAC)	
Exemplares: 	CNPS - (4014-1) - ADD - TS - -- - 86001 - MAC/86 - 1997.00393 - DIS
CPAC - (4870-1) - UPC - TS - PP - CRI3320 -  - CRI3320 - DIS
CPAC - (4870-2) - UPC - TS - PP - T 36/86 -  - T36/86 - DIS