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Influence of laurophyllous species and chestnut on soil weathering and clay mineral assemblages

English title Influence of laurophyllous species and chestnut on soil weathering and clay mineral assemblages
Applicant Egli Markus
Number 107488
Funding scheme Project funding (Div. I-III)
Research institution Geographisches Institut Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Pedology
Start/End 01.04.2005 - 31.03.2007
Approved amount 102'190.00
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Keywords (4)

clay mineralogy; soil chemistry; climate change; biosequences

Lay Summary (English)

Lay summary
In recent decades numerous non-indigenous species of the evergreen broad-leaved (laurophyllous) type have started to colonise forests of southern Switzerland and northern Italy. Since about 1950 many species of the laurophyllous type cultivated in gardens began to spread which is especially due to increased winter temperatures. The colonisation of laurophyllous species is an obvious indication of fast and accelerating climate change that is also likely to be accompanied by the development of long-term ecosystem disequilibria. With respect to the changes in the vegetation cover, the question arises if or to which extent they influence soil mineralogy and chemistry and therefore soil quality. Our study includes the investigation of changes in the soil chemistry and clay mineralogy on selected sites. In southern Switzerland, the common forest vegetation at sites < c. 1000 m a.s.l. predominantly consists of chestnut species. However, chestnut species do not reflect the original forest vegetation as they have been introduced by the Romans c. 2000 years ago. The older vegetation would be a Quercetum-Betuletum forest that can be occasionally found in the area Locarno/Ascona/Cannobio. We would like to study the long-term influence of chestnut (c. 2000 years) on soil chemistry and clay mineralogy.
Our proposed investigation includes, thus, a short-term (c. 40-50 years) and a long-term effect (c. 2000 years) of changing vegetation on soil properties. We assumed that on the long-term as well as on the short-term level changes in the soil will be observable.
Special emphasis was given on clay mineralogy and soil organic matter and their qualitative and/or semi-quantitative changes between the sites. Soil mineralogy (clay fraction and fine earth) was studied with XRD and FT-IR. Measurements on some selected samples with Mössbauer spectroscopy allow us to characterize Fe inthe oxihydroxides and to identify the specific transformation reactions. Further steps include the determination of weathering losses and of mineralogical transformations in typical soil profiles (down to the C horizon). Due to the expected relation of organic matter composition and clay mineralogy, the quantity of fulvic and humic acids was determined. Additionally, fulvic acids were chemicalliy characterized by IR. These results were compared with the mineraloy to observe mineral-organic matter interactions. The methodological approach allowed to furnish precious details of short- to long-term weathering rates and transformation of mineral phases due to differences in the vegetation.
Direct link to Lay Summary Last update: 21.02.2013

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Associated projects

Number Title Start Funding scheme
100117 Influence of laurophyllous species and chestnut on soil weathering and clay mineral assemblages 01.04.2003 Project funding (Div. I-III)