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Title (Primary) Influence of reduced S inputs on the sulfate pool in the humus layer and sulfate uptake in Pinus sylvestris L. as indicated by natural isotope variations of sulfur and oxygen
Author Schulz, H.; Giesemann, A.; Gehre, M.;
Journal Journal of Applied Botany and Food Quality - Angewandte Botanik
Year 2004
Department ISOBIO; BOOEK;
Volume 78
Issue 1
Language englisch;
Abstract The natural isotope composition (delta(34)S and delta(18)O values) of sulfate (SO42-) was determined in humus layers and needles from adult Scots pine stands at three sites between 1993 and 2001, which differed markedly regarding both mean SO2 concentrations and annual mean throughfall rates of SO42--S (Neuglobsow<Taura<Rosa). The isotope measurements were complemented by delta(34)S and delta(18)O analyses of atmospheric SO2 and SO42- in throughfall as well as in samples of external bark layer in order to identify S sources. In all three areas delta(34)S values of H2O-soluble SO42- in the humus layer were similar to the mean delta(34)S values of throughfall and bark surface SO42- (range of +3.6 to +6.0%). A depletion of delta(34)S in sulfate was not observed. This indicates that atmospheric deposition and not the mineralization of organic S is the main source of this inorganic SO42- pool. However, comparison of the delta(18)O values in SO42- from atmospheric deposition showed that H2O-soluble SO42- in the humus layer had been depleted by several per mil (+4.5 to +8.6parts per thousand). These results show clearly that a considerable proportion of H2O-soluble sulfate is derived from mineralization of organic S compounds. On the other hand, temporal variations in the natural isotope ratios of SO42- were only found for O-18. The delta(18)O values of H2O-soluble SO42- in humus layers and in pine needles have significantly increased since 1993, indicating that Scots pines took up deposited sulfate, which was probably reversibly bound onto the surface of Fe-humus complexes. This part of H2O-soluble SO42- pool with higher delta(18)O values is released and is more and more plant-available, because the S depositions were decreased between 1993 and 2001.
ID 4535
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=4535
Schulz, H., Giesemann, A., Gehre, M. (2004):
Influence of reduced S inputs on the sulfate pool in the humus layer and sulfate uptake in Pinus sylvestris L. as indicated by natural isotope variations of sulfur and oxygen
J. Appl. Bot. Food Qual. - Angew. Bot. 78 (1), 18 - 24