The properties and development of soils derived from pumiceous tuff of the 1883 Krakatau eruption were studied on Rakata island during 1983 and 1989. Field observations on soil profiles of different altitude and topography, and laboratory data, revealed that in a period of 100 years soil development has resulted in the formation of a pronounced A-horizon of 5–15 cm thickness underlaying an AC or weak B horizon. Solum development commonly reaches to a depth of approximately 25 cm. The dominant process of soil formation was decomposition of organic matter and aggregation of soil particles in the surface horizon. There was also a slight indication of iron and fine clay translocation but base cations were accumulating in the surface horizon. Soils at 600 m altitude and higher commonly contained lower base saturation, pH, and weatherable minerals, and higher exchangeable A1 and H than those at lower altitudes. The dominant clay minerals were montmorillonite, kaolinite and other layer silicate clays. It is believed that the clays were not formed pedogenically. Some pedons at higher altitudes were dominated by amorphous material in the clay fraction.
KeywordsClay Montmorillonite Kaolinite Clay Fraction Silicate Clay
Unable to display preview. Download preview PDF.
- Baak, J. A.: De mineralogische samenstelling van enkele recente vulkanische asses van Java. Landbow 6/7, 269–274 (1948)Google Scholar
- Birkeland, P. W.: Pedology, weathering, and geomorphological research. Oxford University Press, 1974.Google Scholar
- Escher, B. G.: De Krakatau groep als vulkaan. Handelingen v.h. Eerste Ned. Ind. Natuurs. Congres. Waltevreden, pp. 28–35 and 198–219, 1919.Google Scholar
- Hardjosoesastro, R.; Dai, J.: Pumiceous tuff of the eruption of Krakatau in 1883 on Rakata island and its development. In: Sastrapradja, D. et al. (eds.), Symposium on 100 year development of Krakatau and its surroundings. LIPI, Jakarta 1983.Google Scholar
- Keller, W. D.: Bonding energies of some silicate minerals. Amer. Mineralogist 39, 783–793 (1954)Google Scholar
- Neumann van Padang, M.: Catalogue of the active volcanoes of the world including sulfatara fields. Part 1: Catalogue of the active volcanoes of Indonesia. International Volcanological Association, Napoli 1951.Google Scholar
- Newscome, D.: Soil development on Rakata. In: Flenley, J. R.; Richards, K. (eds.), The Krakatau Centenary Expedition. Final Report. Miscellaneous Series 25, 83–102. Department of Geography, University of Hull, 1982.Google Scholar
- Treub, M.: Notice sur la nouvelle flore de Krakatau. Annals. Jard. Bot. Buitenzorg 7:213–223 (1888)Google Scholar
- Van Baren, J.: Properties and constitution of a volcanic soil built in 50 years in the East Indian Archipelago. Med. Landb. Hogesch. Wageningen, Verh. 6, 1–29 (1931)Google Scholar
- Whittaker, R.: Aspects of vegetation on Rakata. In: Flenley, J. R.; Richards, K. R. (eds.), The Krakatau Centenary Expedition. Final Report. Miscellaneous Series 25, 55–82. Department of Geography, University of Hull, 1982.Google Scholar