Emission Changes in Production and Oxidation of Methane from Japanese Rice Paddy Fields

DOI JASI Web Site 5 Citations

Bibliographic Information

Other Title
  • 水田からのメタン発生と水田土壌におけるメタン生成・酸化分解
  • スイデン カラ ノ メタン ハッセイ ト スイデン ドジョウ ニ オケル メタ

Search this article

Abstract

Seasonal change of methane emission rates from rice paddies was determined by using a closed chamber method. Production rates and oxidation potential of methane in the paddy soil were also measured by incubating the soils in the field under either N_2 atmosphere (production) or air-methane (4 : 1, oxidation) atmosphere. Nutrient treatments studied were of two kinds : mineral fertilizer either with (straw plot) or without (mineral plot) rice straw. 1) Annual emission rates of methane were 20.5 and 15.3 gm^<-2> for the rice straw plot and the no straw plot, respectively. 2) Production rates of methane ranged between 0.00 and 4.90 mg kg^<-1>d^<-1> under in situ conditions. The production rates in the 0-1 and 2-3 cm layers were higher than those in the other layers throughout the flooding period at the no straw plot. In contrast, the layer having the highest production rate shifted to the deeper layer with time during the flooding period at the straw plot. The amount of methane emission accounted for 7.3-39.8% of the calculated amount of methane production in the paddy soils. 3) Oxidation potentials for methane ranged 3.0 and 277.9 mg kg^<-1>d^<-1>. The oxidation potentials in the 0-1 cm layer were always higher than others at both the plots. Assuming that oxidation of methane occurred at the top 1 cm layer in paddy soils and production of methane did below 1 cm, ratio of the oxidation rates to the production rates (ox./pr.) ranged between 4 and 116.The ratio in the no straw plot was higher than that in the rice straw plot. 4) There was a significant positive correlation between emission rates of methane and the ratio of pr./ox. which was represented by the equation ; Y=2.09×10^<-3>X-2.02 (r=0.939). 5) These results suggest that a significant part of the methane produced in paddy soil is probably oxidized either in the surface layer of the paddy soils or in the rhizosphere of rice plants.

Journal

Citations (5)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top