A lysimeter study on the effect of temperature on CO2 emission from cultivated peat soils

摘要

A lysimeter method was evaluated for its suitability in gas emission studies by studying the effect of temperature on CO2 emissions (dark respiration) from cultivated peat soils. The study was carried out with organic soils from two locations in Sweden, a typical cultivated fen peat with low pH and high organic matter content (Örke) and a more uncommon fen peat with high pH and low organic matter content (Majnegården). A drilling method with minimal soil disturbance was used to collect 12 undisturbed soil lysimeters per site. CO2 emission was measured weekly from the vegetated lysimeters and the results were compared with data from incubation experiments. The CO2 emissions measured in the lysimeter experiment were in the same range as those in other studies and showed a similar increase with temperature as in the incubation experiment. With climatic and drainage conditions being similar in the lysimeter experiment, differences in daytime CO2 emission rates between soils (483 mg ± 6.9 CO2 m-2 h-1 from the Örke soil and 360 ± 7.5 mg CO2 m-2 h-1 from the Majnegården soil) were presumably due to soil quality differences. Q10 values of 2.1 and 3.0 were determined in the lysimeter experiment and of 1.9 to 4.5 in the incubation experiment for Örke and Majnegården respectively. CO2 emission data fitted well to a semi-empirical equation relating CO2 emissions to air temperature. The lysimeter method proved to be well suited for CO2 emission studies.