Sensitivity of soil respiration to moisture and temperature

The sensitivity of soil respiration to moisture and temperature was evaluated in three soils from the Atlantic temperate humid zone (Galicia, NW Spain) dedicated to different types of land use (forest, grassland and cropland).Samples of the soils were incubated in the laboratory for 42 days under different temperature (10, 15, 20, 25, 30, 35 °C) and moisture (40, 60, 80, 100% of field capacity) conditions.Emission of CO 2 from Grassland soil was higher than from the other soils.However, despite the different organic matter contents and biochemical activities in the three soils, temperature and moisture were the main factors affecting respiration.It was not possible to demonstrate the effect of soil use on the temperature sensitivity of organic matter mineralization.Sensitivity to temperature was accurately determined by Q 10 expressions, but some results indicate that for correct estimation of Q 10 in the incubation experiments, the CO 2 emission data obtained during the first few days of incubation should be disregarded.Furthermore, the sensitivity of the soil organic matter to temperature was higher at low soil moisture contents.This finding was surprising as it is generally considered that temperature has a greater effect on respiration in nearly saturated soils than in drier soils.