Details

Autor(en) / Beteiligte

• Bhattacharyya, P.
• Roy, K.S.
• Neogi, S.
• Dash, P.K.
• Nayak, A.K.
• Mohanty, S.
• Baig, M.J.
• Sarkar, R.K.
• Rao, K.S.

Titel

Impact of elevated CO2 and temperature on soil C and N dynamics in relation to CH4 and N2O emissions from tropical flooded rice (Oryza sativa L.)

Ist Teil von

• The Science of the total environment, 2013-09, Vol.461-462, p.601-611

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2013

Quelle

MEDLINE

Beschreibungen/Notizen

• A field experiment was carried out to investigate the impact of elevated carbon dioxide (CO2) (CEC, 550μmolmol−1) and elevated CO2+elevated air temperature (CECT, 550μmolmol−1 and 2°C more than control chamber (CC)) on soil labile carbon (C) and nitrogen (N) pools, microbial populations and enzymatic activities in relation to emissions of methane (CH4) and nitrous oxide (N2O) in a flooded alluvial soil planted with rice cv. Naveen in open top chambers (OTCs). The labile soil C pools, namely microbial biomass C, readily mineralizable C, water soluble carbohydrate C and potassium permanganate oxidizable C were increased by 27, 23, 38 and 37% respectively under CEC than CC (ambient CO2, 394μmolmol−1). The total organic carbon (TOC) in root exudates was 28.9% higher under CEC than CC. The labile N fractions were also increased significantly (29%) in CEC than CC. Methanogens and denitrifier populations in rhizosphere were higher under CEC and CECT. As a result, CH4 and N2O-N emissions were enhanced by 26 and 24.6% respectively, under CEC in comparison to open field (UC, ambient CO2, 394μmolmol−1) on seasonal basis. The global warming potential (GWP) was increased by 25% under CEC than CC. However, emissions per unit of grain yield under elevated CO2 and temperature were similar to those observed at ambient CO2. The stimulatory effect on CH4 and N2O emissions under CEC was linked with the increased amount of soil labile C, C rich root exudates, lowered Eh, higher Fe+2 concentration and increased activities of methanogens and extracellular enzymes. •In tropical rice, CH4 and N2O emissions were increased by 26, 24.6% under elevated CO2.•Global warming potential of CH4 & N2O emissions increased by 25% in elevated CO2.•Labile soil C pool was increased in the range of 23–38% under elevated CO2 (550ppm).•TOC of root exudates and labile soil N pool were increased by 29% in elevated CO2.•Methanogens and denitrifier population were increased under elevated CO2.