HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Nierop, K. G. J. Articles by Verstraten, J. M. Search for Related Content PubMed Articles by Nierop, K. G. J. Articles by Verstraten, J. M. GeoRef GeoRef Citation Agricola Articles by Nierop, K. G. J. Articles by Verstraten, J. M. Related Collections Dryland Soils Water Quality Carbon Sequestration

SOIL CHEMISTRY

Organic Matter in Volcanic Ash Soils under Forest and Páramo along an Ecuadorian Altitudinal Transect

Institute for Biodiversity and Ecosystem Dynamics (IBED), Earth Surface Processes and Materials (ESPM), Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, the Netherlands

^* Corresponding author (k.g.j.nierop{at}science.uva.nl).

The volcanic ash soils along an altitudinal transect in Guandera Biological Station in northern Ecuador have been developed under varying vegetation around the upper forest line. Generally, the soils currently covered by forest are composed of Fulvic Andosols (melanic index >1.7) while those under páramo (tropical alpine grasslands) have developed into Melanic Andosols. This vegetation effect on soil formation is believed to be associated with differences in organic matter composition. In this study, we examined whether Fulvic Andosols differed from Melanic Andosols in organic matter composition. Using analytical pyrolysis techniques, we found hardly any differences in the organic matter characteristics related to vegetation cover, not even between soils that supposedly have been covered by forest and páramo for millennia. Small differences were found within the lipid compounds, while the polysaccharides and lignin were virtually absent from the (deeper) mineral soil horizons. The low abundance of polysaccharides in soils that have undergone severe organic matter decomposition is not unusual for most soils, but is uncommon in other Andosols studied with the same pyrolysis techniques.

Abbreviations: OM, organic matter • SOM, soil organic matter • THM, thermally assisted hydrolysis and methylation • UFL, upper forest line