Emission of CO₂ from the soil and immobilization of carbon in microbes in a subtropical mixed oak forest ecosystem, Manipur, Northeast India

Emission of CO₂ from the soil and immobilization of carbon in the microbes were studied in two forest stands of a subtropical mixed oak forest located at Langol hills near Imphal city, Manipur (24°45’N lat. and 93°55’E long.) at an altitude ranging from 780 to 910 m amsl, using alkali absorption method and chloroform fumigation extraction method. The CO₂ emission rate was lowest during the winter season (149.00 and 138.49 mg CO₂ m⁻² h⁻¹) and highest during the rainy season (250.94 and 220.48 mg CO₂ m⁻² h⁻¹) in both the forest stands. The immobilization of carbon in the microbes was maximum during the rainy season (1182.6 and 740.73 μg g⁻¹) followed by summer (738.32 and 392.92 μg g⁻¹), and minimum during the winter season (465.14 and 382.58 μg g⁻¹) across the two stands. Out of the total soil organic carbon, maximum immobilization of microbial C occurs in the rainy season (2.7%) and minimum in the summer season (1.2%). Thus, emission of CO₂ from the soil and immobilization of carbon in the microbes are strongly influenced by the seasons.