Data/hora: 11/05/2024 09:58:19

Biblioteca(s): 	Embrapa Milho e Sorgo.	
Data corrente: 	05/04/1994	
Data da última atualização: 	19/10/2023	
Autoria: 	SANTANA, D. P.	
Afiliação: 	DERLI PRUDENTE SANTANA, CNPMS.	
Título: 	Soil formation in a toposequence of oxisols from Patos de Minas region, Minas Gerais State, Brazil.	
Ano de publicação: 	1984	
Fonte/Imprenta: 	1984.	
Páginas: 	129 p.	
Idioma: 	Inglês	
Notas: 	Tese (Doutorado) - Purdue University, West Lafayette.	
Conteúdo: 	Tuffite-derived soils, widespread in the Patos de Minas Region, are among the most productive soils of Minas Gerais State, Brazil, and have potential for greater agricultural development. To understant  how properties of these Ustox soils relate to landscape features, a toposequence with 40 m relief in 500 m, was sampled on the flatter stretches of a valley slope. From summit to footslope positions the following trends in properties of the B horizon (about 1 m depth) were observed: 1. moist soil color graded progressively from dusky red to strong brown with mottels; 2. mica content increased; 3. hydroxy interlayerd vermiculite, present in very small amounts, showed no clear trends: 4. kaolinite content decreased in an irregular fashion; 5. hydroxy interlayerdvermiculite, present in very small amounts, showed no clear trends; 4. kaolinite content decreased in an irregular fashion; 5. gibbsite and anatase decreased; 6. hematite decreased; 7. goethite increased slightly: 8. maghemite was absent in the footslope positions and present in small amounts in backslope and summft positions; and 9, magnetic in susceptibility decreased steadlly. Downslope movement of 51 or preferential removal of Si from upper slope positions controls the wethering and formation of clay minerals in the landscape. In the  lower slope positions, which are wetter than upper positions, goethite formation apparently is favored relative to hematite and maghemite. Goethite was found to have a smaller crystallite size and more Al-substitution than hemetite. 
Differential X-ray Diffraction Analysis (DXRD) combined with multipleregression analysis provided a quantitative estimate of the different iron oxide minerals present in the sample. A hand magnet attached to a small spring balance provide a quick and reliable quantitative estimate of soil magnetic susceptibility in the field. A simple redness index was calculated for mottled horizons. Also, a new redness index that emphasizes the role of hue in soil color relationships was used. 	
Palavras-Chave: 	Brasil; Formação; Formation; Genese; Genesis; Minas Gerais; Morfologia; Morphology; Oxissolo; Patos de Minas.	
Thesagro: 	Cerrado; Latossolo; Mineralogia; Oxisol; Solo.	
Thesaurus Nal: 	Brazil; mineralogy; soil.	
Categoria do assunto: 	--	
URL: 	http://ainfo.cnptia.embrapa.br/digital/bitstream/item/90293/1/t-derli.pdf	
Registro original: 	Embrapa Milho e Sorgo (CNPMS)	
Exemplares: 	CNPS - (4067-1) - ADD - TS - -- - 84015 - SAN/84 - 1997.00513 - DIS
CPATU - (31344-1) - ADD - TS - -- - 1984/026 - SAN - 1984/026 - DIS
CNPMS - (2895-1) - UPA - TS - DD -  -  -  - DIS
CPAC - (26202-1) - ADD - TS - -- - CRI6743 -  - CRI6743 - DIS