Straw Application Altered CH_4 Emission,Concentration and ^(13)C-Isotopic Signature of Dissolved CH_4 in a Rice Field  

作　　者：ZHANG Xiao-Yan ZHANG Guang-Bin JI Yang MA Jing XU Hua CAI Zu-Cong 

机构地区：[1]State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008(China) [2]Graduate University of Chinese Academy of Sciences,Beijing 100049(China)

出　　处：《Pedosphere》2012年第1期13-21,共9页土壤圈（英文版）

基　　金：Supported by the National Natural Science Foundation of China (Nos. 40921061 and 41071169);the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA05020200)

摘　　要：CH4 emission and the concentration of dissolved CH4 in soil solution and floodwater in a rice field and their stable carbon isotopic signatures as affected by straw application were investigated in 2009 in a field experiment at Jurong, Jiangsu Province, China. Straw application increased CH4 emission and CH4 concentration in the soil solution and floodwater. A positive seasonal correlation was also observed in the variation between CH4 flux and CH4 concentration in soil solution. The seasonal total CH4 emission （51.6 g CH4 m^-2） in Treatment WS （straw applied） was about 168% higher than that in Treatment CK （without straw）. The emitted CH4 and CH4 in soil solution were initially relatively enriched, then depleted and finally enriched again in 13C in both treatments, while CH4 in floodwater became isotopically heavier. The carbon isotopic signature of emitted CH4 and CH4 in floodwater averaged around -62%o and -45%0 for both treatments, respectively, and was not significantly influenced by the application of straw. However, straw application caused the CH4 in soil solution to be significantly depleted in lac during the middle of the rice season, and the mean δ13C value was lower in WS （-57.5‰） than in CK （-49.9‰）. Calculation from the isotopic data showed that straw application increased the fraction of CH4 oxidized, causing no significant difference in the δ13C value of the emitted CH4 between the two treatments.CH 4 emission and the concentration of dissolved CH 4 in soil solution and floodwater in a rice field and their stable carbon isotopic signatures as affected by straw application were investigated in 2009 in a field experiment at Jurong,Jiangsu Province,China.Straw application increased CH 4 emission and CH 4 concentration in the soil solution and floodwater.A positive seasonal correlation was also observed in the variation between CH 4 flux and CH 4 concentration in soil solution.The seasonal total CH 4 emission(51.6 g CH 4 m 2) in Treatment WS(straw applied) was about 168% higher than that in Treatment CK(without straw).The emitted CH 4 and CH 4 in soil solution were initially relatively enriched,then depleted and finally enriched again in 13 C in both treatments,while CH 4 in floodwater became isotopically heavier.The carbon isotopic signature of emitted CH 4 and CH 4 in floodwater averaged around 62‰ and 45‰ for both treatments,respectively,and was not significantly influenced by the application of straw.However,straw application caused the CH 4 in soil solution to be significantly depleted in 13 C during the middle of the rice season,and the mean δ 13 C value was lower in WS(57.5‰) than in CK(49.9‰).Calculation from the isotopic data showed that straw application increased the fraction of CH 4 oxidized,causing no significant difference in the δ 13 C value of the emitted CH 4 between the two treatments.

关 键 词：δ13CH4 CH4 flux CH4 oxidation FLOODWATER soil solution 

分 类 号：X511[环境科学与工程—环境工程] X831