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Characterization of Humic Acids in Mountainous Meadow Soils and Burozems of the Crimea Using 13C-NMR
Eurasian Soil Science - A comparative analysis of organic matter in the mountainous soils under the main plant communities of the Crimea was performed. The humus state of burozems and mountainous... 相似文献
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Processes of initial soil formation were studied on long-term monitoring plots on dump rocks of quarry no. 3 of the Phosphorite production company in Kingisepp district of Leningrad oblast. Observations were performed in 1998, 2004, and 2014. It was shown that vegetation succession on the plots proceeds relatively quickly, and that the species composition of phytocenoses formed is typical of the areas with soddy-calcareous soils. Soil development proved to be correlated with the development of vegetation. Maximum changes in soil characteristics were observed with an increase in the density of forest vegetation and a decrease in the role of herbs. The molecular composition of humic acids in the studied soils remained stable; in particular, the ratio of aliphatic to alkyl aromatic fragments was virtually constant. This phenomenon could be due to the great amount of aliphatic components in the falloff of coniferous species subjected to humification. 相似文献
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R. M. Khalitov E. N. Perova E. V. Abakumov R. R. Suleimanov 《Eurasian Soil Science》2017,50(8):961-970
The mineralogy of soils and parent rocks of the Iremel Ridge has been studied by the methods of micromorphology, laser diffraction, computed X-ray microtomography, and X-ray fluorescence analysis. In hard rock and soil, the major minerals have been identified: quartz, illite, and a chlorite-group mineral (Fe analogue of sudoite), as well as accessory minerals: monazite, xenotime, rutile, zircon, and florencite. It has been found that chlorite, illite, and quartz are present in all horizons of the studied peaty-podzolic soil. Insignificant amounts of mixed-layered mineral and kaolinite could be suggested in the T and EL horizons of peaty-podzolic soil. The mixed-layered mineral is most probably of soil origin, which is related to the transformation of illites inherited from the parent rock under acidic conditions. 相似文献
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E. V. Abakumov 《Eurasian Soil Science》2010,43(5):499-508
Original data on humus-forming substances and their elemental and biochemical compositions in Antarctic soils are discussed.
Mosses, lichens, algae, remains of higher vascular plants, and penguin guano of two types differ considerably in their chemical
compositions. This leads to significant differences in the formation of humic substances in plant materials themselves in
the course of their transformation. However, no significant differences in the composition of humus in the fine earth of soils
developing under different humus-forming materials have been revealed, which may be related to the extremely low rates of
humification. Significant differences between the soils of Antarctic landscapes proper and the soils of the Subantarctic King
George Island are only observed in the humus enrichment with nitrogen. The soils of Antarctica are low-humus soils with the
humate-fulvate or fulvate types of humus. 相似文献
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Elena N. Kashinskaya Evgeniy P. Simonov Galina I. Izvekova Aleksey N. Parshukov Karl B. Andree Mikhail M. Solovyev 《Journal of fish diseases》2020,43(1):23-38
Using the approach of sequencing the V3-V4 region of the 16S rRNA gene, we have analysed the bacterial diversity associated with the distinct compartments of the gastrointestinal tract of perch (Perca fluviatilis) and cestodes (Proteocephalus sp.) parasitizing their digestive tract. The dominant microbiota associated with cestodes (Proteocephalus sp.) was represented by bacteria from the genera Serratia, Pseudomonas and Mycoplasma. By comparing the associated microbiota of perch and cestodes, a clear difference in bacterial composition and diversity was revealed between the community from the stomach content and other parts of the gastrointestinal tract of fish. Microbiota associated with cestodes was not significantly different in comparison with microbiota of different subcompartments of perch (mucosa and content of intestine and pyloric caeca) (ADONIS, p > .05) excluding microbiota of stomach content (ADONIS, p ≤ .05). PICRUSt-based functional assessments of the microbial communities of perch and cestodes indicated that they mainly linked in terms of metabolism and environmental information processing and could play an important role in the nutrition and health of host. 相似文献
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Clarkson JR Baquero E Shubert VA Myshakin EM Jordan KD Zwier TS 《Science (New York, N.Y.)》2005,307(5714):1443-1446
The two-step laser excitation scheme of stimulated emission pumping (SEP) induces shifts of a single water molecule between two remote hydrogen bonding sites on trans-formanilide. This reaction can be initiated by selective excitation of either isomer (CO-bound or NH-bound) with different SEP excitation wavelengths. Energy (E) thresholds for isomerization in both directions have been measured [796 wave numbers = E(CO-->NH) = 988 wave numbers and 750 wave numbers = E(NH-->CO) = 988 wave numbers], and the energy difference DE between the CO-bound and NH-bound isomers was extracted (-238 wave numbers = DE = +192 wave numbers). 相似文献
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Possibilities of NMR spectroscopy with 13C nuclei application to the study of soil organic matter and its various fractions is considered. This is a non-destructive method, which is particularly valuable in the analysis of various fractions of soil organic matter. It is regarded as a direct method, and, unlike most of indirect methods, it allows one to obtain reliable estimates of the ratio between virtually all groups of carbon atoms in different organic molecules, including those in humus specimens. Owing to impulse technique and high sensitivity, 13C-NMR spectra may be obtained immediately from soil samples without any extraction operations. The modern technique of obtaining spectra, their mathematical processing (Fourier transform), and data interpretation are considered. The results of applying 13C-NMR to the study of humus substances, water-soluble fractions of soil organic matter, and soil litters from different natural zones are discussed. 相似文献