Accumulation of Atmospheric Carbon by Crops in Rotation and the Effect of Fertilization Systems on the Accumulation of Organic Carbon by Cultivated Sod-Podzol Soil

Abstract

The study reports experimental data on the accumulation and loss of organic carbon in sod-podzol soil over six rotations of a long-term station experiment. It was found that, during photosynthesis, spring barley plants bound to organic compounds 2.84–3.25 t C/ha from the atmosphere (10.3–11.6 t CO₂/ha) and meadow clover of the second year of rotation bound 4.23–5.19 t C/ha (15.1–18.6 t CO₂/ha) over the growing season, depending on experimental variant. Cultivated crops sequestered from the atmosphere 82.28–99.31 t of CO₂/ha or 22.4–27.1 t C/ha over a rotation of the eight-field crop rotation, depending on the soil fertilization system. Long-term use of cultivated land without fertilizers led to a decrease in carbon content in the soil by 13.5% in relation to the initial level. The soil of the station experiment was characterized by the maximum content and stock of organic carbon under saturation of tilled land with manure at a dose of 20 t/ha and an equivalent amount of NPK. Over six rotations, carbon content increased by 15% of the initial content in the 0–20 cm layer, while the carbon stock increased by 5 t/ha in this layer and by 32 t/ha in the 0–100 cm layer. Mean value of the carbon-protective capacity of the studied soil varied between 29 and 31 g/kg in the 0–20 cm layer regardless of the applied fertilization systems. The quantity and qualitative composition of biomass, entering the soil under different systems of fertilization, had a significant effect on the accumulation of organic carbon.