Soil development in the forefield of Skaftafellsjökull glacier, SE-Iceland

Olga Kolbrún Vilmundardóttir (Faculty of Life and Environmental Sciences, University of Iceland)
Guðrún Gísladóttir (Faculty of Life and Environmental Sciences, University of Iceland; Earth Science Institute, University of Iceland)
Rattan Lal (Faculty of Life and Environmental Sciences, University of Iceland; Carbon Management and Sequestration Center, SENR/OARDC/FAES, The Ohio State University, USA)

Since the end of the Little Ice-Age, Icelandic glaciers have been retreating after reaching their maximum extent in 1890. The recession exposes surfaces where new soil formation commences. Time is one of the five soil forming factors and where the history of glacial recession is known it is possible to assess the role of time on the rate of pedologic processes. Thus, it is possible to assess the role of time on the rate of pedologic processes. The aim of this research was to investigate the changes in soil properties and constituents over time.
Soils were sampled along three end moraines representing surfaces of ~ 8, 65 and 120 years and in adjacent birch forest for comparison. The parameters analysed were: A-horizon, bulk density, organic matter, organic carbon, total nitrogen, soil reaction, and clay content.
Bulk density decreased with time as did the soil pH. The depth of A-horizon, proportion of organic matter and soil organic carbon increased over time. After 120 years, the A-horizon was 8 cm thick and the soil contained 1.72 kg C m-2 of organic carbon in the fine earth fraction, still much under the full carbon sequestering capacity of the birch soil, which contained 2.97 kg C m-2. The young soils contained a substantial amount of secondary clay minerals characteristic of soils of volcanic origin. Conclusively, the young proglacial soils have not yet matched the properties of the more developed soil of the birch forest.

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