摘要：To support low-emission development strategies (LEDS) in the agriculture sector in Vietnam, this paper estimates marginal abatement cost curves (MACC) for mitigation options for rice cultivation in Vietnam: short-duration rice variety, draining of rice fields and reduced use of fertilizer or alternate wetting and drying (AWD). The MACC, which show the average cost of reducing total greenhouse gas emissions by one unit in rice cultivation in Vietnam, are the first attempt at using representative data on rice management practices and their costs are realized by farmers on the field. Typically, these estimates are usually developed using expert judgment and assuming perfect adoption of the technology. In addition, the MACC uses with region-specific estimates of carbon emissions from rice fields. Furthermore, when estimating the potential for potential for carbon emissions abatement from alternative management practices, we consider the behavioral constraints in adopting management practices, rather than just focusing on the technical potential. Among these potential mitigation options, in the South (An Giang Province), the largest percentage area is under low fertilizer and short-duration variety, followed by short duration with AWD. In the North (Thai Binh Province), majority of the area is under low fertilizer and short-duration variety. In the North, low fertilizer and short-duration variety appear to be production cost-reducing options, but do not have as much mitigation potential compared to alternate wetting and drying (AWD). However, AWD is a production cost-increasing option, implying that farmers may need a financial incentive to adopt AWD. Furthermore, farmers have trouble adopting AWD given its complexity. Therefore, when accounting for adoption constraints for AWD the abatement potential reduces significantly for AWD. This implies that the Government of Vietnam will have to focus on areas and communities that are more likely to adopt these technologies: farmers with ability to control irrigation and farmers with deeper pockets and access to high value markets. In the South, the use of short-duration variety had higher emissions. Short-duration varieties lead to lower methane (CH4) emissions but can have higher nitrous oxide (N2O) emissions. The explanation for this outcome is that the South has more rain and hotter temperatures, which can lead to higher nitrous oxide emissions. Thus, the short-duration variety needs to be revisited as a mitigation option in the South. In particular, this option needs to be combined with reduced fertilizer use to be an effective mitigation option. The application of organic amendments and crop residue management were not practiced much in the South. Therefore, these options could be not be analyzed. Overall, only AWD was a viable option, which is why we did not generate MACCs for the South.
