Application of sulfate-containing amendments is often suggested as a mitigation option to reduce methane (CH4) emissions from rice ( Oryza) fields. This paper discusses the mechanism and potential of this mitigation option, reviews the relevant experimental data, and presents first, indicative costs of application. CH4 emission data for rice fields with sulfate-containing amendments are compiled to reinterpret the resulting reduction in CH4 emission and find a general relationship between emission reduction and amount of sulfate applied. The reduction in CH4 emission depends on the amount of sulfate applied. However, absolute emission reduction is location specific and cannot be derived from the amount of sulfate (SO2-4) applied only. We established a logarithmic relationship, across locations, between SO2-4 application and fractional emission reduction relative to the emission of the non-amended control field. Recycling of SO2-4 in the rhizosphere was essential to explain the observed reductions in CH4 emission for a number of the experiments. The cost of applying SO2-_4-containing fertilizers varies across countries and depends on local fertilizer prices. Since a fractional reduction is obtained, the cost-efficiency in terms of CH4 mitigation per unit of SO2-4 applied will be highest in high-emitting rice production systems. Provided the proper target areas are selected, the cost of SO2-4-containing fertilizer as a mitigation option to reduce CH4 emissions in rice fields is estimated at 5–10 US dollar per Mg CO2-equivalent.
|Journal||Mitigation and Adaptation Strategies for Global Change|
|Publication status||Published - 2001|