Methane efflux in rice paddy field under different irrigation managements

Diovane Freire Moterle,Ângela Da Cas Bundt,Vagner João Moro,Leandro Souza Da Silva,Luis Antonio De Avila,Tiago Zschornack,Cimélio Bayer

doi:10.1590/s0100-06832013000200014

Abstract

Paddy rice fields may contribute to methane (CH4) emission from soil due to anaerobic conditions after flooding. Alternatives to continuous flooding irrigation in rice have been developed to mitigate CH4 efflux into the atmosphere. This study aims to investigate the effects of irrigation managements in the CH4 efflux during the rice growing season. An experiment was carried out at in Santa Maria, Rio Grande do Sul State, Brazil, during 2007/08 and 2009/10 growing seasons. The treatments were continuous flooding and intermittent irrigation in 2007/08 and continuous flooding, intermittent irrigation and flush irrigation in 2009/10. Intermittent irrigation is effective in mitigating CH4 efflux from rice fields when climatic conditions enable water absence during cultivation, but its efficiency depends on the electrochemical soil conditions during the flooding cycles.

Highlights

The increase in greenhouse gas content, such as carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), in the atmosphere during the last years, could be responsible for the increase of the planet’s temperature (IPCC, 2007)
In 2007/08 growing season, CH4 efflux started on the 5th day after flooding (DAF) along with soil reduction and continued rising until approximately 28 to 33 DAF (Figures 1a and 2a,b)
This is because labile C from soil organic matter (SOM) was used as substrate by methanogenic bacteria (Cai et al, 1997)

Summary

Introduction

The increase in greenhouse gas content, such as carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), in the atmosphere during the last years, could be responsible for the increase of the planet’s temperature (IPCC, 2007). Alternatives to continuous flooding have been developed with different objectives, such as to reduce the volume of water used and increase water use efficiency (Bouman, 2001; Bouman & Tuong, 2001), to reduce toxicity effects of organic compounds and inorganic ions (Bouman et al, 2007); to reduce risks of water reservoir contamination by pesticides (Martini et al, 2012); and to mitigate CH4 emission (Solomon et al, 2007) Another advantage of these alternative systems could be better soil and water conservation (Stone, 2005)

Objectives

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Results

Conclusion