Resumo

ARIAS, Fulvio et al. Mineralogía de la fracción arcilla de algunos suelos cultivados con banano en las llanuras aluviales del Caribe de Costa Rica. Agron. Costarricense [online]. 2010, vol.34, n.2, pp.197-222. ISSN 0377-9424.

Abstract Soil clay mineralogy of banana-cultivated soils in the Caribbean lowlands of Costa Rica. This study includes the characterization of the clay mineralogy of banana soils from 11 watersheds of the Caribbean alluvial lowlands, using RX diffraction and dissolution methods. These results confirm the abundance of montmorrillonite, metahalloisite, vermiculite and plagioclases, together with small amounts of allophane, gibbsite and iron oxides like hematite, maghemite and magnetite. Chlorite was not detected but illite was found in some samples. The use of dissolutionand estequiometric techniques allowed us to identify amorphous materials, probably allophane, in soil RE-16 in the Tortuguero river basin. Soils northwest of the watershed of rivers Vueltas, Silencio and Parismina, were dominated by metahalloisite and montmorrillonite; they were classified as Inceptisols with Andic properties (Andic Eutrudepts, Aquandic Endoaquepts), Dystric Inceptisols (Fluventic Dystrudepts) and Andisols (Typic Hapludands). Soils southwest of that watershed were dominated by montmorrillonite, vermiculite and metahalloisite; they were classified as Eutric Inceptisols of  alluvial origin (Fluventic Eutrudepts, Dystric Fluventic Eutrudepts, Fluvaquentic Eutrudepts, Fluventic Endoaquepts) and Inceptisols with drainage problems (Fluventic Endoaquepts, Fluvaquentic Epiaquepts). The montmorillonite, vermiculite and allophane are formed in the hillsides of the watershed (cordilleras Central and Talamanca) and later deposited in the lowlands by river flooding; metahalloisite is formed by transformation of halloisite and gibbsite developed from allophanic materials.

Palavras-chave : RX diffraction; clay mineralogy; montmorrillonite; illite; vermiculite; metahalloysite; allophane; gibbsite; alluvial soil; Caribbean lowlands; Costa Rica.

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