Measurement of the carbon isotopic ratio in paddy ecosystem components by mass spectrometer

In the attempt to introduce the determination of stable carbon isotopic ratio for the analysis of carbon cycle in paddy ecosystem, a sample preparation apparatus and preparation methods were examined. A sample combustion and refining apparatus to prepare samples for the measurement of stable carbon isotopic ratio was contrived. With this apparatus, the method was established to collect and refine the carbon in samples, such as standard materials, organics, total carbonic acid and methane, in the form of CO2. The apparatus and the method were applied to the measurement of carbon isotopic ratio in paddy-rice plants, other plants, paddy water, soil, etc. from a paddy field of the Agriculture Research Center. In this paddy ecosystem, the carbon isotopic ratio in its components was distributed widely. Thus, the measurement appears to be an effective means for the analysis of the carbon cycle in paddy ecosystem. (Mori, K.)