Effect of temperature on soil respiration in a Chinese fir forest

Abstract

Soil samples collected from the surface soil (0–10 cm) in an 88-year-old Chinese fir (Cunninghamia lanceolata) forest in Nanping, Fujian, China were incubated for 90 days at the temperatures of 15°C, 25°C and 35°C in laboratory. The soil CO₂ evolution rates were measured at the incubation time of 2, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80 and 90 days. The results showed that CO₂ evolution rates of soil samples varied significantly with incubation time and temperature during the incubation period. Mean CO₂ evolution rate and cumulative amount of CO₂ evolution from soil were highest at 35°C, followed by those at 25°C, and 15°C. Substantial differences in CO₂ evolution rate were found in Q₁₀ values calculated for the 2nd and 90th day of incubation. The Q₁₀ value for the average CO₂ evolution rate was 2.0 at the temperature range of 15–25°C, but it decreased to 1.2 at 25–35°C. Soil CO₂ evolution rates decreased with the incubation time. The cumulative mineralized C at the end of incubation period (on the 90th day) was less than 10% of the initial C amounts prior to incubation.

Keywords

forest soil / Chinese fir / respiration / temperature