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471.
Theresa Bonatotzky Franz Ottner Egill Erlendsson Guðrún Gísladóttir 《European Journal of Soil Science》2022,73(2):e13224
Icelandic soils develop in a dynamic environment affected by both natural processes and anthropogenic impacts. We present an extensive investigation of soil mineralogy and pedogenesis in a disturbed (i.e., by solifluction) pedon under such conditions. The study focuses on two distinct tephra layers, a rhyolitic tephra from the Öræfajökull eruption in 1362 CE (Ö1362) and a basaltic Veiðivötn tephra from 1477 CE (V1477). Both tephra layers form an important parent material in the study area south of Vatnajökull, Iceland. The Andosol developed from tephra and aeolian material, rich in volcanic glass. The pH (H2O) values were between 5.5 and 6.6 and clay mineralogy displayed a predominance of allophanic material in both soil and tephra. The pedon can be seen in its early stage of chemical weathering and soil development. Despite the overall predominance of non- and poorly-crystalline short-range order secondary materials and Fe (hydr)oxides in the clay-size fraction, we found indication of smectite. High exchangeable Ca2+ and Mg2+ concentrations reflect enhanced aeolian input of volcanic material, while elevated exchangeable-Na+ concentrations are most likely caused by the oceanic composition of precipitation. The impact of erosion and aeolian processes on pedogenesis seemed to be higher between the deposition of Ö1362 and V1477, than in the soils above. Both, soil and tephra layers appeared disturbed by erosion–deposition processes over time. Characterised by a significantly coarser particle size composition, low soil organic carbon (SOC) content, and a more diverse mineralogy, a distinct fluvial sediment layer at 10–30 cm depth appeared sharply contrasting to the other soil layers in the profile. This possibly reflects the diverse composition of glaciofluvial material from a landslide originating from a Kvíárjökull moraine in the north. Changed weathering patterns and properties in the soils above the Ö1362 tephra indicated soil degradation following the deposition of the rhyolitic tephra. 相似文献
472.
Variability of certain chemotypes in three accessions of German chamomile (Matricaria chamomilla L.)
Bettina Faehnrich Pietro Nemaz Chlodwig Franz 《Genetic Resources and Crop Evolution》2014,61(7):1237-1244
In 203 analyzed chamomile plants, several compounds appreciated for their medicinal value, were evaluated qualitatively and quantitatively. α-Bisabolol and its oxides A and B were measured by gas chromatography; matricine as a precursor of chamazulene, was assessed semi-quantitatively by matching visually thin layer chromatography bands with a concentration range of the pure substance and the flavonoids apigenin and apigenin-7-glycoside were quantified by high performance liquid chromatography. Mean values of all compounds were compared in the three chamomile accessions ‘Manzana’, ‘Lutea’ and ‘Hungarian 2’. Correlations between different substances over all data were calculated. Moreover, certain groups combining particular properties according to their desired purpose or specificity, were formed. Their incidence in the particular chamomile varieties was determined. ‘Manzana’, a tetraploid cultivar, exhibited the highest share of the valuable bisabolol–matricine-type and the lowest ratio of bisabolol-oxides to bisabolol. To develop ‘high-quality-populations’, defined individuals of this cultivar shall be selected for further breeding. 相似文献
473.
Franz Conen Kristiina Karhu Jens Leifeld Barbara Seth Pekka Vanhala Jari Liski Christine Alewell 《Soil biology & biochemistry》2008,40(10):2703-2705
Predictions of future climate change critically depend on the temperature sensitivity of soil organic carbon decomposition. One question of debate is whether temperature sensitivity differs between young or labile and old or more stable carbon pools. We re-analysed soil that has previously led to the conclusion that old soil carbon is more temperature sensitive. The re-analysis gave different results compared to the earlier study, most likely due to small differences in an otherwise very similar experimental approach. This study illustrates how conclusions may depend upon details of the experimental setting. 相似文献
474.
Martinek B Bago Z Flöck M Hochsteiner W Schilcher F Kofler J 《Veterinary journal (London, England : 1997)》2006,172(1):181-184
Clinical, ultrasonographic, radiographic and pathological findings of a chondrosarcoma diagnosed in an 8-year-old Simmental cow are reported. The primary site was located in the cartilage of the right scapula at the angulus cranialis. The tumour had already spread to the lungs at the time of diagnosis. This is the first report of a bovine scapula chondrosarcoma. 相似文献