Open AccessInfluence of elevated carbon dioxide concentrations on methane emission and its associated soil microflora in rice ecosystem
Author(s) -
S. K. Rajkishore,
M. Maheswari,
K. S. Subramanian,
R. Prabhu,
G. Vanitha
Publication year - 2021
Publication title -
journal of applied and natural science
Language(s) - English
Resource type - Journals
eISSN - 2231-5209
pISSN - 0974-9411
DOI - 10.31018/jans.v13isi.2773
Subject(s) - methane , carbon dioxide , zoology , ecosystem , population , environmental chemistry , chemistry , nitrogen , agronomy , carbon fibers , biology , ecology , materials science , demography , organic chemistry , sociology , composite number , composite material
The dynamics of methane emission and its associated soil microflora in rice ecosystem as a response to elevated CO2 concentrations were studied in open top chamber (OTC) conditions. The treatments consisted of three levels of CO2 (396, 550 and 750 µmol mol-1) and three levels of nitrogen (0, 150 and 200 kg ha-1) and replicated five times in a completely randomized design. The data showed that elevated [CO2] significantly (P ? 0.01) increased the DOC throughout the cropping period with the values ranging from 533 to 722 mg L-1 and 368 to 501 mg L-1 in C750 and Camb, respectively. Methane emission rates were monitored regularly during the experiment period and it was revealed that elevated [CO2] had increased the methane emissions regardless of stages of crop growth. It was observed that methane emissions were significantly higher under [CO2] of 750 µmol mol-1 by 33 to 54 per cent over the ambient [CO2] of 396 µmol mol-1. Consistent with the observed increases in methane flux, the enumeration of methanogens showed a significant (P ? 0.01) increase under elevated [CO2] with the population ranging from 5.7 to 20.1 x 104 CFU g-1 of dry soil and 5.1 to 16.9 x 104 CFU g-1 of dry soil under C750 and Camb concentrations, respectively. Interestingly, even though higher methanotrophs population was recorded under elevated [CO2], it could not circumvent the methane emission. Overall, the results of OTC studies suggest that methane mitigation strategies need to be explored for the future high CO2 environments.