Data/hora: 27/07/2024 02:20:25

Biblioteca(s): 	Embrapa Solos.	
Tipo da produção científica: 	Artigo em Periódico Indexado	
Circulação/Nível: 	Internacional - A	
Data corrente: 	03/12/2008	
Data da última atualização: 	11/11/2021	
Autoria: 	BARTHÈS, B. G.; KOUAKOUA, E.; LARRÉ-LARROUY, M.-C.; RAZAFIMBELO, T. M.; LUCA, E. F. de; AZONTONDE, A.; NEVES, C. S. V. J.; FREITAS, P. L. de; FELLER, C. L.	
Afiliação: 	BERNARD G. BARTHÈS, UR SeqBio/IRD; ERNEST KOUAKOUA, Cabinet Expertise Ernest Kouakoua; Marie-Christine Larré-Larrouy, UR SeqBio/IRD; Tantely M. Razafimbelo, UR SeqBio/IRD; Edgar F. de Luca, Horto Florestal Edmundo Navarro de Andrade; Anastase Azontonde, Laboratoire des Sciences du Sol, Eaux et Environnement; Carmen S. V. J. Neves, UEL; PEDRO LUIZ DE FREITAS, CNPS; Christian L. Feller, UR SeqBio/IRD.	
Título: 	Texture and sesquioxide effects on water-stable aggregates and organic matter in some tropical soils.	
Ano de publicação: 	2008	
Fonte/Imprenta: 	Geoderma, Amsterdam, v. 143, n. 1/2, p. 14-25, Jan. 2008.	
DOI: 	https://doi.org/10.1016/j.geoderma.2007.10.003	
Idioma: 	Inglês	
Conteúdo: 	Many tropical soils include sesquioxides, which influence the stability of soil organic matter (OM) and aggregation to an extent that is not fully characterized. The present study was carried out on a range of 18 topsoil samples (0-10 cm) from low-activity clay (LAC) soils from sub-Saharan Africa and Brazil, and aimed: (i) at characterizing the size distributions of water-stable aggregates and organic constituents, (ii) at studying how these distributions were affected by texture and sesquioxides, and (iii) how they interacted. The distributions of stable aggregates were generally dominated by macroaggregates (N200 ìm), and those of organic constituents by fine OM (b20 ìm). Aggregation was not clearly affected by soil texture, while total soil carbon (Ct) and the amount of carbon (C) as fine OM increased with soil content in clay plus fine silts (b20 ìm). Stable acroaggregation correlated with Ct and with C amount as fine OM, but each of them correlated more closely with citrate-bicarbonate-dithionite-extractable aluminium (Al), which was not expected. Stable macroaggregation also correlated with C amounts as coarse- and medium-sized OM (N200 and 20-200 ìm, respectively), but each of them correlated more closely with oxalate-extracted Al. These results suggested that for the LAC tropical soils under study OM and aggregate stability depended closely on Alcontaining sesquioxides, on Al-substituted crystalline hematite and goethite especially. These sesquioxides also seemed to play a dominant role in the relations between aggregation and OM. As far as soils rich in sesquioxides are concerned, this confirmed that OM is not the main aggregating agent, and suggested that physical protection within aggregates is not necessarily the main mechanism for OM stabilization. However, as soil sesquioxide content cannot be managed easily, the effect of land use on soil OM and aggregation was determinant at the local scale: indeed, for a given location, stable macroaggregation, Ct and C amount as fine OM generally decreased with land use intensification (i.e. cultivation, tillage, reduced surface cover).	
Palavras-Chave: 	Agregação; Sesquióxidos; Solos cauliníticos.	
Thesagro: 	Alumínio; Matéria Orgânica; Textura.	
Categoria do assunto: 	P Recursos Naturais, Ciências Ambientais e da Terra	
Registro original: 	Embrapa Solos (CNPS)	
Exemplares: 	CNPS - (13569-1) - UPC - AP - DD -  -  - 2008.00054 - DIS