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Natural 13C abundance of the organic matter pools in Haplic Chernozemстатья
Дата последнего поиска статьи во внешних источниках: 10 июля 2024 г.
- Авторы: Artemyeva Z.S., Zazovskaya E.P., Zasukhina E.S., Tsomaeva E.V., Kogut B.M.
- Журнал: Moscow University Soil Science Bulletin
- Том: 77
- Номер: 4
- Год издания: 2022
- Издательство: Allerton Press Inc.
- Местоположение издательства: United States
- Первая страница: 258
- Последняя страница: 265
- DOI: 10.3103/S0147687422040044
- Аннотация: Natural 13C abundance of different organic-matter (OM) pools of haplic chernozem (the Streleskayasteppe plot of the Central Chernozemic State Biospheric Reserve) isolated by granulodensitometric fractionation was studied. Natural variations of the 13C/12C ratio (δ13C) allowed the sequence to be confirmed of OM decomposition in soils, which follows a continuum from fresh and partially decomposed organic matter in the discrete OM (Free and Occluded) to significantly/completely processed in the mineral-associated OM (Clay and Res). This is reflected in the increase of the δ13C value during passing from discrete to mineral-associated OM. All studied OM pools are subjected to microbial processing, but in different extent. Free OM, despite the fact that it consists of well-recognized plant material, is not always the freshest and most undecomposed organic matter. The “lighter” isotope signature of occluded OM as compared to free OM, despite its obvious higher degree of microbial processing, may be due to its physical protection in microaggregates (which are unstable under sonication) within the soil structural units. The most microbial processed mineralassociatedorganic matter (Clay and Res fractions) is characterized by the “heaviest” isotopic signature. The isotopic composition of carbon in the whole soil is mainly determined by the Res fraction due to its quantitatively domination in the soil bulk. The conceptual scheme allows one to quantify the carbon C) fluxes in the OM pool/soil system. It was revealed that the main C fluxes in the OM pools go from the Free OM to the Res fraction through microaggregates that are unstable under sonication. The most probable C fluxes into the whole soil are unstable under the sonication microaggregates, as well as the Res fraction, which are characterized by the lowest Δ13C values (difference between Δ13C of “source” and “product”).
- Добавил в систему: Артемьева Зинаида Семеновна