The Q10 relationship of microbial respiration in a temperate forest soil

Our objective was to study the effect of temperature on rates of soil respiration in the A-, E- and B-horizons of a temperate forest (Durham, North Carolina, USA). Soil samples were incubated for several months at 4, 15, 22 and 38°C and respiration was measured frequently during incubation. For each soil horizon, rates of CO2 evolution varied significantly with time of incubation and temperature. The A-horizon had the highest initial rates of soil respiration, followed by the B- and E-horizon soils for each temperature. The initial rates of respiration from the A-soil horizon increased with temperature in accordance with the Arrhenius equation. The Q10 for the A horizon calculated from initial respiration rates varied from 1.9 to 1.7 over the temperature range of 4°C to 28°C. Generally rates of respiration decreased during the incubation, although the total fraction of carbon respired from the soil was small ( < 3%).