Microbiological characterization of soddy soils of the Severnaya Dvina River floodplain     

R. S. Kutuzova  N. I. Vorob’ev  M. V. Gamova  L. A. Popova  Yu. V. Kruglov 《Eurasian Soil Science》2009,42(2):225-234

Soils of virgin lands, hayfields, and plowed lands were studied in the Severnaya Dvina River floodplain. The potential possibilities of microbiological processes were shown to increase in the summer in the soils in the following sequence as related to the increasing number of copiotrophs in them: virgin land—hayfield—plowed land. Copiotrophs are microorganisms that use easily available organic substances, including nitrogencontaining ones. The increase in their number enhanced the nitrification, while other microbiological processes became weaker. The number of fungi increased due to the improvement of the water-air regime. As the agricultural use of the soils became more intense, the cellulose decomposition slowed down, the actual nitrification ability was lowered, and the carbon content in the physiologically active microbial biomass decreased because the area of the natural plant cover was reduced from the virgin land to the plowed land.  相似文献   

The effect of tree roots on the redistribution of <Superscript>137</Superscript>Cs in the soils of pine and birch forests of the radioactive contamination zone     

A. I. Scheglov  O. B. Tsvetnova  E. P. Popova 《Moscow University Soil Science Bulletin》2016,71(2):83-87

Accumulation and distribution of ¹³⁷Cs by the root systems of forests in the radioactive contamination zone of Bryansk oblast have been discussed. It has been found that the phytomass and distribution of roots of pine and birch trees along the soil profile in the studied BGCs differ considerably. The specific activity of ¹³⁷Cs in the roots changes depending on their diameter: the lowest specific activity is observed in small fractions of the roots, and the highest one in large fractions. It has been shown that the contribution of roots in the total reserves of ¹³⁷Cs in the soil layer of 0–50 cm of various biogeocenoses is different: the largest contribution is characteristic for birch forests (1.66%) with variation of this parameter in separate soil layers from 1.12 to 3.53%, while the contribution for pine forests is lower (0.97%) with the variation from 0.82 to 7.5%. The contribution of roots to the overall contamination of soils in the studied plant communities increases with depth.  相似文献   

Cadastral valuation of land contaminated with radionuclides     

A. N. Ratnikov  P. M. Sapozhnikov  N. I. Sanzharova  D. G. Sviridenko  T. L. Zhigareva  G. I. Popova  A. V. Panov  I. Yu. Kozlova 《Eurasian Soil Science》2016,49(1):116-124

The methodology and procedure for cadastral valuation of land in the areas contaminated with radionuclides are presented. The efficiency of rehabilitation measures applied to decrease crop contamination to the levels satisfying sanitary-hygienic norms is discussed. The differentiation of cadastral value of radioactively contaminated agricultural lands for the particular farms and land plots is suggested. An example of cadastral valuation of agricultural land contaminated during the Chernobyl Nuclear Power Plant accident is given. It is shown that the use of sandy and loamy sandy soddy-podzolic soils with the ¹³⁷Cs contamination of 37–185 and >185 kBq/m² for crop growing is unfeasible. The growing of grain crops and potatoes on clay loamy soddy-podzolic soils with the ¹³⁷Cs contamination of 555–740 kBq/m² is unprofitable. The maximum cadastral value of radioactively contaminated lands is typical of leached chernozems.  相似文献   

Irrigation scheduling for furrow-irrigated maize under climate uncertainties in the Thrace plain, Bulgaria   总被引：1，自引：1，他引：0  

Zornitsa Popova  Luis S. Pereira   《Biosystems Engineering》2008,99(4):587-597

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Quantitative and qualitative characterisation of humic products with spectral parameters     

Filcheva  Ekaterina  Hristova  Mariana  Nikolova  Pavlina  Popova  Todorka  Chakalov  Konstantin  Savov  Valentin 《Journal of Soils and Sediments》2018,18(8):2863-2867

Purpose

The application of different humic products for the treatment of soils and plants has increased in recent years. The characteristics of humic products, such as the content and composition of organic carbon and the maturity, provide valuable information which is essential for an adequate application. Such information is crucial for manufacturers, business consultants and users involved in the production, distribution and implementation of humic products. This article presents the correlation between the quantitative indicators of commercial humic products and their spectral characteristics via measurements in the ultraviolet spectrum at 300 nm, in the visible area at 445 and 665 nm and in the near-infrared spectrum at 850 nm.

Materials and methods

We evaluated humic products (liquid and solid) of different origins. Via wet combustion, the content of total organic carbon in humic products can be determined. The precipitation of humic acids from the starting solution determines the composition of the humic products in terms of humic acids (HAs) and fulvic acids (FAs). The dissolution of HAs determines their concentration by titration, while the specific extinction can be assessed via spectrophotometry via measuring the absorption of HAs spectra at the following wavelengths: 300, 465, 665 and 850 nm. The degree of aromaticity and condensation of humic products determines the optical density of the HAs via the E₄/E₆ ratio.

Results and discussion

The content of total organic carbon varied widely from 0.55 to 37.5% across all groups. The content of carbon in HAs, as a percentage of the total carbon in fulvic-type humic products, ranged from 1.29 to 16.00%, while in humic-type products, it ranged from 51.43 to 91.92%. The minimum value of the E₄/E₆ ratio was 2.97, while the maximum value was 6.35. We observed a direct relationship between the dominant type of acids in humic products and the E₄/E₆ ratio.

Conclusions

The optical density of HAs indicates their quality characteristics. The presented optical characteristics for humic products show that there is a direct relationship, especially between HAs/FAs and E₄/E₆ ratios. Measurement at 300 nm (E₃₀₀) in the near-ultraviolet area and at 850 nm (E₈₅₀) in the near-infrared area can increase the range of the spectral study.

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Functional divergence of former alleles in an ancient asexual invertebrate     

Pouchkina-Stantcheva NN  McGee BM  Boschetti C  Tolleter D  Chakrabortee S  Popova AV  Meersman F  Macherel D  Hincha DK  Tunnacliffe A 《Science (New York, N.Y.)》2007,318(5848):268-271

Theory suggests it should be difficult for asexual organisms to adapt to a changing environment because genetic diversity can only arise from mutations accumulating within direct antecedents and not through sexual exchange. In an asexual microinvertebrate, the bdelloid rotifer, we have observed a mechanism by which such organisms could acquire the diversity needed for adaptation. Gene copies most likely representing former alleles have diverged in function so that the proteins they encode play complementary roles in survival of dry conditions. One protein prevents desiccation-sensitive enzymes from aggregating during drying, whereas its counterpart does not have this activity, but is able to associate with phospholipid bilayers and is potentially involved in maintenance of membrane integrity. The functional divergence of former alleles observed here suggests that adoption of asexual reproduction could itself be an evolutionary mechanism for the generation of diversity.  相似文献