Carbon Stocks and Carbon Protection Capacity of Soddy-Podzolic Soils in Natural and Agricultural Ecosystems of the Cis-Ural Region
2022
Zavyalova, N. E.
The amount of stabilized and protected from decomposition soil organic matter characterizes the carbon protection capacity (CPC) of soil. Experimental data on the accumulation and loss of organic carbon in soddy-podzolic soils (Eutric Albic Retisols (Abruptic, Loamic, Cutanic)) in agrocenoses and background natural cenoses of the Cis-Ural region are presented. The greatest decrease in the Cₒᵣg stock has been found in the soil of permanent clean fallow: the rate of carbon loss in the layer of 0–20 cm in the first seven years reaches 0.04% C/ yr or 1.0 t C/(ha yr). Among arable soils, the soil under the perennial leguminous crop—the oriental goat’s rue (Galéga orientalis)—is characterized by the maximum content and stocks of organic carbon. Over 30 years of permanent cultivation of this crop, carbon stock in the layer of 0–20 cm has increased by 5.4 t/ha, and the thickness of the humus-accumulative soil horizon (A1) has increased up to 36 cm; in the virgin soil of the grass–forb meadow it reaches 22 cm. Natural soils are in equilibrium, the Cₒᵣg content under mixed forest in the layer of 3–20 cm is 2.69 ± 0.02%; under the grass–forb meadow (0–20 cm), 1.25 ± 0.03%; carbon stocks are 41.2 and 31.2 t C/ha, respectively. The average value of the CPC in the layer of 0–20 cm in studied soils varies from 26.1 to 32.9 g C/kg soil and virtually does not depend on the soil management. Significant factors influencing the content of organic carbon in the soil are the quantity and qualitative composition of the biomass entering the soil of agrocenoses.
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