Soil carbon budget in a single-cropping paddy field with rice straw application and water management based on soil redox potential(Environment)

概要

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An ideal state for agroecosystems to mitigate global warming should include both decreasing CO_2 and CH_4 emissions and increasing soil carbon storage. Two-year field experiments were carried out to examine the effects of water management (continuous flooding [CF] and Eh control [EH]) and rice straw management (application [+S] and removal [-S]) on the soil carbon budget in a single-cropping paddy field in Japan. The EH water management based on soil redox potential that the authors have proposed decreased the total CH4 emission during the rice growing period compared with CF. The +S increased CO_2 emission as soil respiration during the non-flooded fallow period compared with -S, but also increased straw residues in the soil. However, there was little evidence for sequential carbon accumulation in the soil over the year by +S. The resultant annual budget of soil carbon was a loss of 32-103g C m^<-2> in the EH+S treatment compared with a loss of 166-188g C m^<-2> in the CF-S treatment. Taking into account the global warming potentials, the EH+S treatment also decreased the total CO_2-equivalent emission compared with the CF-S treatment. Consequently, a combination of appropriate water management and straw application will be an effective option in decreasing both CO_2-equivalent emission and sustaining soil carbon storage.
社団法人日本土壌肥料学会の論文