Pedosphere 18(4): 441--453, 2008
ISSN 1002-0160/CN 32-1315/P
©2008 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Soil formation of “Atlantic rankers” from NW Spain—A high resolution aluminium and iron fractionation study |
J. KAAL1 , M. COSTA-CASAIS1, C. FERRO-VÁZQUEZ1, X. PONTEVEDRA-POMBAL2 and A. MARTÍNEZ-CORTIZAS2 |
1 Instituto de Estudios Galegos Padre Sarmiento, Laboratorio de Arqueologúa del Paisaje (LAr), IEGPS-CSIC-XuGa, Rúa San Roque 2, 15704 Santiago de Compostela (Spain);
2 Departamento de Edafologúa y Quúmica Agrúcola, Fac. Biologúa, Universidad de Santiago (Spain) |
| ABSTRACT |
| Atlantic rankers belong to the group of "cryptopodzolic rankers", which are ubiquitous in the mountainous cool/tempe-rate humid regions of Western Europe. The rankers of Galicia (NW Spain) formed by thousands of years of colluviation. The preponderance of Al-stabilised organic matter (OM) masks the horizonation and polycyclic character (i.e., stratifi-cation) of these soils. Cryptopodzolic rankers are generally thought to be the outcome of podzolisation. This soil type is part of the recent discussion on how to classify soils developed from nonvolcanic parent material having andic properties. To better understand the formation processes of these soils, the Al and Fe fractionation of four typical Atlantic rankers were studied by selective dissolution in acid NH4-oxalate, Na-pyrophosphate and the chlorides of K, La and Cu. A high-resolution sampling approach allowed us to investigate the soils in greater detail than simply sampling by horizon. The rankers studied display a distribution of Fe-and Al-OM complexes that is typical of cryptopodzolic soils. However, these organomineral associations were probably immobile due to the high Al saturation. We argue that the soils owe their characteristic chemical status to external factors rather than to translocation of organomineral associations: variations in Al-OM concentrations could be linked to changes in weathering/leaching intensity and colluviation rates caused by anthropogenic disturbances or changes in regional climate regime. |
| Key Words: Al fractionation, colluviation, cryptopodzolic soil, podzolisation, ranker |
| Citation: Kaal, J., Costa-casais, M., Ferro-vÁzquez, C., Pontevedra-pombal, X. and MartÍnez-cortizas, A. 2008. Soil formation of “Atlantic rankers” from NW Spain—A high resolution aluminium and iron fractionation study. Pedosphere. 18(4): 441-453. |
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