Dynamics of Carbonates in Soils under Different Land Use in Forest-Steppe Area of Russia Using Stable and Radiogenic Carbon Isotope Data

Abstract

The work is aimed at the analysis of carbonate dynamics in soils under different land use. The studied area is located in the forest steppe -of the Central Russian Upland. Soils were sampled at four sites: a broadleaf forest, an adjacent 50-year continuously cropped field including plots under a corn monoculture, bare fallow, and a crop rotation area with a clean fallow every fourth year. The carbonates' morphology, their chemical composition, as well as their stable and radiogenic isotopes of carbon were studied. Clear-cut distinctions were found in the carbonate distribution throughout the profiles in the microstructure of carbonate pedofeatures, carbon isotopic composition, and radiocarbon age of carbonates between the pairs of the plots as follows: the bare fallow and the crop rotation on the one hand, and the corn monoculture and forest on the other. The distinctions are commonly assumed to result from repeating upward water fluxes, which are different in the bare soils and those with plant cover. A clear difference occurred in the hydrothermal regime for soils with and without plant cover, and was found to be the key factor of the observed differences. In addition, in soils under plant cover, the carbonate migration upward occurs due to process of transpiration, whereas in soils devoid of plants, it occurs due to physical evaporation.

Inorganic carbon is overlooked in global soil carbon research: A bibliometric analysis

“…The SIC pool is larger than the atmospheric CO 2 pool or terrestrial plant biomass C. It is often assumed that SIC changes very slowly over geological time scales because its contribution to biological cycles is much lower than SOC ( Schlesinger, 1985 ). Many recent studies, however, report that SIC is far from stable and can be vulnerable to land use changes and intensive crop production, soil acidification, and water flow and recharge – processes that can reduce and even deplete SIC stocks within a few decades ( Khokhlova and Myakshina, 2018 , Raza et al, 2020 , Raza et al, 2021 , Kim et al, 2020 , Zamanian et al, 2018 ). Even SIC stocks deeper than 7 m are vulnerable to loss through agricultural practices ( Kim et al, 2020 ).…”

Isotope Characteristics (δ13C, δ18O) of Continental Carbonates from Permian‒Triassic Rocks in the Northeastern Russian Plate: Paleoclimatic and Biotic Reasons and Chemostratigraphy

“…Values of δ 18 O in the pedogenic carbonates depend on the oxygen isotope composition in the soil moisture and temperature, while δ 13 C values characterize variations of the isotopic composition of soil carbon dioxide (CO 2 ) . These parameters vary significantly in different regions of the world and depend on the isotopic composition in meteoric sediments of different physicogeographic and climatic zones owing to their geographic position (remoteness from equator, World Ocean, altitude), humidity (degree of aridization or humidization of the locality), plant type (S-3 and S-4 type photosynthesis), and climatic fluctuations (Abels et al, 2016;Bai et al, 2017;Bayat et al, 2017;Cerling et al, 1989;Dambaev et al, 2016;Deutz et al, 2001;Ekart et al, 1999;Gocke and Kuzyakov, 2015;Jin et al, 2009;Khokhlova and Myakshina, 2018;Liu et al, 1996;Quade et al, 1989Quade et al, , 2007Retallack, 2005;Stevevson et al, 2005;Zamanian et al, 2016).…”

Isotope features (δ13С, δ18О) of continental carbonates from Permian and Triassic boundary deposits Northeast of Russian plate: paleoclimatic and biotic causes, chemostratigraphy

“…Значения δ 18 О педогенных карбонатов зависят от изотопного состава кислорода почвенной влаги и температуры почв, а величины δ 13 С характеризуют вариации изотопного состава почвенной углекислоты (СО 2 ). Эти параметры существенно различаются в разных регионах земного шара и зависят от изотопного состава метеорных осадков разных физико-географических и климатических зон, обусловленного географическим положением (удаленностью от экватора, Мирового океана, высоты над уровнем моря), влажностью (степенью аридизации или гумидизации местности), характером растительности (С-3 и С-4 тип фотосинтеза), колебаниями климата [Quade et al, 1989[Quade et al, , 2007Cerling et al, 1989;Liu et al, 1996;Ekart et al, 1999;Deutz et al, 2001;Stevevson et al, 2005;Retallack, 2005;Jin et al, 2009;Gocke, Kuzyakov, 2015;Zamanian et al, 2016;Дамбаев и др., 2016;УДК 550.42+551.736.3+551.76.1 (470.1+470.3) ИЗОТОПНЫЕ ОСОБЕННОСТИ (δ 13 С, δ 18 О) КОНТИНЕНТАЛЬНЫХ КАРБОНАТОВ ЛИТОЛОГИЯ И ПОЛЕЗНЫЕ ИСКОПАЕМЫЕ № 6 2019 Abels et al, 2016;Bai et al, 2017;Bayat et al, 2017;Khokhlova, Myakshina, 2018].…”