Effects of elevated CO_2 on CH_4, and N_2O emissions from submerged rice soil(The Annual Meeting of the Society in 2003)

Weiguo Cheng, Kazuyuki Yagi, Hidemitsu Sakai, Kazuhiko Kobayashi
2003 Tsuchi to biseibutsu  
An experimcnt was carried out in Six controlled ・ environment chambers to study the effects of elevated CO20n CH . , and N20 emissions from submerged rice soi1 . In three chambers , CO2 concentration was maintained at 350 μ mol mo1 −1 ( arnbient CO2 ) , while in another three , CO2 was controlled at 650 μ mol mo 工 一 1 ( elevated CO2) throughout a rice growing season from May 15 to September 25 , 2002 .At the heading stage of rice ,200 %o δ 13 C − CO2 was fed to all chambers for three days , the
more » ... δ i3C value of emitted CH , and disso 星 ved CH . , ill flooding water and soil solution were measured by an IRMS befOre and after し he feeding . The results showed that the increase in CH , emission by elevated COz was significant afLer the flowering stage of ricc , regardless of the transport pathways , either plant mediated or ebullition ・ diffusion . The emitted CH4 by ebullition − diffusion accounted for l5 − 20 % of total emission ill both alnbient arld elevated CO2 condltions . N20 was emitted only first 3 weeks after rice transplanting and fertilization 、 There was no difFerence in N20 emissiQn between ambient and elevated COz . Injected N fertilizer h1 5 cm below soil surface did not bring N20 emission at booting stage . The dissolved CH4 and N20 in fioeding water alld soil solution also shown same trerld with CH4
doi:10.18946/jssm.57.2_154_2 fatcat:dsvoppeogvayxfn4hbjhoatzui