Total Soil CO₂ Efflux from Drained Terric Histosols

Area of Science:

• Soil Science
• Environmental Science
• Ecology

Background:

• Histosols, particularly Terric Histosols rich in organic matter, cover 8-10% of Lithuania.
• Drained Histosols are significant contributors (>25%) to Lithuania's Land Use, Land Use Change, and Forestry (LULUCF) sector's greenhouse gas (GHG) emissions.

Purpose of the Study:

• To investigate carbon dioxide (CO2) fluxes in drained Terric Histosols.
• To analyze the relationship between soil CO2 efflux and environmental factors in Lithuania.
• To compare CO2 efflux rates between forested and grassland ecosystems on drained Histosols.

Main Methods:

• Measured total soil CO2 efflux and environmental parameters (temperature, soil chemistry, moisture, water table) in drained Terric Histosols.
• Conducted measurements across three native forest stands and perennial grasslands during the growing seasons of 2020 and 2021.
• Analyzed soil organic carbon and total nitrogen concentrations and their ratios.

Main Results:

• Total soil CO2 efflux showed the highest rates during summer months.
• Soil CO2 efflux was statistically significant and strongly correlated with soil and air temperature.
• Perennial grasslands exhibited approximately 30% higher total soil CO2 efflux compared to forested land.

Conclusions:

• Soil temperature is a key driver of CO2 efflux from drained Terric Histosols in Lithuania.
• Land cover type influences CO2 emissions, with grasslands showing higher efflux than forests.
• Further research is required to determine the net carbon dioxide balance of these organic soils.