Article

Paddy and Water Environment

, Volume 10, Issue 4, pp 281-289

Comparison of methanotrophic bacteria, methane oxidation activity, and methane emission in rice fields fertilized with anaerobically digested slurry between a fodder rice and a normal rice variety

  • K. T. WinAffiliated withGraduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology
  • , R. NonakaAffiliated withGraduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology
  • , A. T. WinAffiliated withGraduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology
  • , Y. SasadaAffiliated withGraduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology
  • , K. ToyotaAffiliated withGraduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology Email author 
  • , T. MotobayashiAffiliated withFaculty of Agriculture, Tokyo University of Agriculture and Technology
  • , M. HosomiAffiliated withFaculty of Engineering, Tokyo University of Agriculture and Technology

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Abstract

Methane oxidation activity (MOA), methanotrophic bacteria (MOB), and CH4 emission in a paddy field fertilized with anaerobically digested slurry were compared between two varieties: a fodder rice variety Leaf star (LS) and a normal rice variety Kinuhikari (KN). Average MOA and MOB per unit dry root were significantly higher in KN (7.1 μmol g−1 CH4 g−1 dry root h−1 and 3.7 × 107 MPN g−1 dry root, respectively) than in LS (4.3 μmol g−1 CH4 g−1 dry root h−1, 2.1 × 107 MPN g−1 dry root), although MOA in the rice root per whole plant was not significantly different since root biomass of LS (1.5 g dry root plant−1) was significantly higher than that of KN (1.2 g dry root plant−1). MOA in the soil ranged from 0.031 to 0.087 μmol g−1 CH4 g−1 dry soil h−1, but there were no significant differences in both depths (0–5 and 5–15 cm) between the two rice varieties. MOA in the rhizosphere soil was significantly different between the rice varieties at flowering, but not at tillering. Methane emission in the field was lower and MOA and MOB in the rice root were higher in LS than in KN at tillering, but the reverse results were found at flowering and maturity stages. Total CH4 emission during a growing period was not significantly different between LS (27.4 ± 16.9 g CH4 m−2) and KN (24.0 ± 19.5 g CH4 m−2). There was a significant negative relationship between CH4 emission and rice root MOB (P < 0.01) or MOA (P < 0.05) and significant positive relationship was observed between root MOA and MOB (P < 0.01). This study revealed that choice of rice variety might be an important environmental issue in paddy cultivation since it can influence MOA and MOB in rice root and rhizosphere soil which relate with CH4 emission.

Keywords

Kinuhikari Leaf star Methanotrophs Methane oxidation Methane emission Root biomass