![Hier klicken, um den Treffer aus der Auswahl zu entfernen](images/unchecked.gif) |
Titel |
Critical Evaluation of Soil Pore Water Extraction Methods on a Natural Soil |
VerfasserIn |
Natalie Orlowski, Dyan Pratt, Lutz Breuer, Jeffrey McDonnell |
Konferenz |
EGU General Assembly 2017
|
Medientyp |
Artikel
|
Sprache |
en
|
Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 19 (2017) |
Datensatznummer |
250145925
|
Publikation (Nr.) |
EGU/EGU2017-9905.pdf |
|
|
|
Zusammenfassung |
Soil pore water extraction is an important component in ecohydrological studies for the
measurement of δ2H and δ18O. The effect of pore water extraction technique on resultant
isotopic signature is poorly understood. Here we present results of an intercomparison of
commonly applied lab-based soil water extraction techniques on a natural soil: high pressure
mechanical squeezing, centrifugation, direct vapor equilibration, microwave extraction, and
two types of cryogenic extraction systems. We applied these extraction methods to a natural
summer-dry (gravimetric water contents ranging from 8% to 15%) glacio-lacustrine,
moderately fine textured clayey soil; excavated in 10 cm sampling increments to a depth of 1
meter. Isotope results were analyzed via OA-ICOS and compared for each extraction
technique that produced liquid water. From our previous intercomparison study among the
same extraction techniques but with standard soils, we discovered that extraction
methods are not comparable. We therefore tested the null hypothesis that all extraction
techniques would be able to replicate the natural evaporation front in a comparable
manner occurring in a summer-dry soil. Our results showed that the extraction
technique utilized had a significant effect on the soil water isotopic composition.
High pressure mechanical squeezing and vapor equilibration techniques produced
similar results with similarly sloped evaporation lines. Due to the nature of soil
properties and dryness, centrifugation was unsuccessful in obtaining pore water for
isotopic analysis. Cryogenic extraction on both tested techniques produced similar
results to each other on a similar sloping evaporation line, but dissimilar with depth. |
|
|
|
|
|