@article{oai:nagoya.repo.nii.ac.jp:00014614, author = {森泉, 純 and 森, 嘉貴 and 江川, 紗矢香 and 山澤, 弘美 and MORIIZUMI, Jun and MORI, Yoshiki and EGAWA, Sayaka and YAMAZAWA, Hiromi}, journal = {名古屋大学加速器質量分析計業績報告書}, month = {Mar}, note = {The characteristics of decomposition of soil organic matter (SOM) in a rice paddy have been studied in terms of cycling of carbon, especially radioactive 14C, in a rice paddy. Production rate of CO2 from incubated paddy soil under aerobic condition and that of CH4 under anaerobic condition were measured for periods of more than 100 d. The incubations were undergone at warmer temperature than real condition of rice paddy to "accelerate" SOM decomposition several times faster than the real condition. Both production rates of CO2 and CH4 showed rapid decrease to 10^-10 kg-C (kg-dry soil)-1s^-1 for 10 d just after starting the incubations, and then they decreased moderately. For CO2 the variations in carbon isotopic ratios (δ13C, Δ14C) were also measured during the incubation. At first the δ13C of SOM-derived CO2 was ca. -22 ‰, and it rapidly decreased to less than -28 ‰ to become close to that of SOM (-29.2 ‰). The variation in Δ14C of CO2 also showed slightly higher value for the fist several days than those for the period after 20 d. However, all of Δ14C measurements were less than 0, and this means their 14C ages were older than 1960s, the era of atmospheric nuclear weapon testing, apparently. Since these apparent ages are inconsistent to the time scale of SOM decomposition measured in this study, older SOM as well as modern one might be attributed to source of the CO2., 第23回名古屋大学年代測定総合研究センターシンポジウム平成22(2010)年度報告}, pages = {180--186}, title = {水田土壌中有機物の分解に由来するCO2およびCH4の炭素同位体比の経時変化}, volume = {22}, year = {2011} }