• Energy Research

Rice production is a significant source of greenhouse gas (GHG) emissions in the national budget of many Asian countries, but the extent of emissions varies strongly across agro-environmental zones. It is important to understand these differences in order to improve the national GHG inventory and effectively target mitigation options. This study presents a meta-analysis of CH4 database emission factors (EFs) from 36 field sites across the rice growing areas of Vietnam and covering 73 cropping seasons. The EFs were developed from field measurements using the closed chamber technique. The analysis for calculating baseline EFs in North, Central and South Vietnam in line with the Intergovernmental Panel on Climate Change (IPCC) Tier 2 methodology was specified for the three cropping seasons being early-(E), mid-(M) and late-year (L) seasons. Calculated average CH4 EFs are given in kg ha−1 d−1 and reflect the distinct seasons in North (E: 2.21; L: 3.89), Central (E: 2.84; M+L: 3.13) and South Vietnam (E: 1.72; M: 2.80; L: 3.58). Derived from the available data of the edapho-hydrological zones of the Mekong River Delta, season-based EFs are more useful than zone-based EFs. In totality, these average EFs indicate an enormous variability of GHG emissions in Vietnamese rice production and represent much higher values than the IPCC default. Seasonal EFs from Vietnam exceeded IPCC defaults given for Southeast Asia corresponding to 160% (E), 240% (M) and 290% (L) of the medium value, respectively.

Abstract The production of irrigated rice is increasingly challenged by freshwater scarcity. Water saving technologies such as Alternate Wetting and Drying (AWD) allow sustaining production levels under reduced water availability. Before implementing such innovations on a large scale, their hydrological impact on the system needs to be assessed. This study investigated the applicability of the water management tool WEAP (Water Evaluation and Planning System) for evaluating the effects of AWD on water use and water resources at field and irrigation system level for two different case studies in Central Luzon, the Philippines. In the first study, the Zeigler Experiment Station (ZES) of the International Rice Research Institute (IRRI) was used for parameterization of WEAP and field-scale assessment of AWD, making use of the availability of spatially and temporally highly resolved data. In the second study, WEAP was applied to an irrigation scheme in the Philippines, the Angat-Maasim River Irrigation System (AMRIS) to assess effects on up- and downstream water resources using lower resolution data. Simulated AWD implementation during the dry season reduced water requirements by 12–27% and 34.3% on ZES and AMRIS, respectively. Additionally, AWD implementation enhanced streamflow in main and lateral canals, and thus increased water availability in the entire irrigation system. We also conducted an ex-ante assessment of future freshwater availability assuming reduced precipitation due to climate change effects alongside with irrigation supply at current levels. WEAP showed that water levels in the reservoir will substantially decline under these circumstances leading to severe water stress in AMRIS. Implementing AWD in such a scenario improved water availability in the system by up to 50%. WEAP proved to be a suitable tool for upscaling different irrigation techniques and assessing their impact on water resources on a large scale. Limitations of the approach and future possibilities for improvements are discussed.

Worldwide, rice production contributes about 10% of total greenhouse gas (GHG) emissions from the agricultural sector, mainly due to CH4 emissions from continuously flooded (CF) fields. Alternate Wetting and Drying (AWD) is a promising crop technology for mitigating CH4 emissions and reducing the irrigation water currently being applied in many of the world's top rice-producing countries. However, decreased emissions of CH4 may be partially counterbalanced by increased N2O emissions. In this case study for the Philippines, the national mitigation potential of AWD is explored using the process-based biogeochemical model LandscapeDNDC. Simulated mean annual CH4 emissions under conventional rice production for the time period 2000 - 2011 are estimated as 1,180163 Gg CH4 yr-1. During the cropping season, this is about +16% higher than a former estimate using emission factors. Scenario simulations of nationwide introduction of AWD in irrigated landscapes suggest a considerable decrease of CH4 emissions by -23%, while N2O emissions are only increased by +8%. Irrespective of field management, at national scale the radiative forcing of irrigated rice production is always dominated by CH4 (>95%). The reduction potential of GHG emissions depends on, e.g., number of crops per year, residue management, amount of applied irrigation water and sand content. Seasonal weather conditions also play an important role, since the mitigation potential of AWD is almost double as high in dry as compared to wet seasons. Furthermore, this study demonstrates the importance of temporal continuity, considering off-season emissions and the long-term development of GHG emissions across multiple years. This study was conducted as part of the multidisciplinary research project ICON: ‘Introducing Non-Flooded Crops in Rice- Dominated Landscapes: Impacts on Carbon, Nitrogen and Water Cycles’. We thank the German Research Foundation (DFG) for its generous funding (FOR 1701, BU1173/13-1/2 and KI1431/3-1/2).

This article provides a comprehensive institutional analysis to better understand the key conditions and incentives relevant for the uptake of alternate wetting and drying (AWD) – a climate-smart irrigation practice in Bangladesh. Practicing AWD in rice production can reduce water consumption by 30% and mitigate methane emissions by 30–70% without yield penalty. Primary research was conducted in Rangpur, Rajshahi, Mymensingh, and Sherpur Divisions. The analysis depicts the dynamic among the stakeholders involved in scaling AWD using the Net-Map tool, and demonstrates the influence of irrigation management systems in the selected catchment areas and the impacts of AWD in rice farming. Findings reveal that AWD-practicing farmers, pump owners, and the Upazila Irrigation Committee are the three most powerful influencers for scaling AWD. The pre-paid irrigation system significantly improves water efficiency and cost-effectiveness when practising AWD. Additionally, AWD leads to a lower frequency of pumping resulting in reduced costs compared to the continuous-flooding practice. Finally, the results guide the formulation of recommendations to create favourable conditions for AWD scaling, which contributes to reducing greenhouse gas emissions and advancing sustainable rice production in Bangladesh.

IntroductionStrategies for increasing rice production in the Asian Mega-Deltas have led to environmental degradation, resource overexploitation, and high greenhouse gas emissions. Certified sustainable production labels can support governments in their efforts to render rice value chains more sustainable by simultaneously fostering planetary and human health. Little is known, however, about how consumers trade off sustainability and health attributes in staple crops such as rice. This study aims to fill this knowledge gap by investigating Vietnamese consumers' preferences and willingness to pay for rice characterized by multi-attribute sustainability and health certification labels.MethodsWe collected empirical data from 410 supermarket consumers in Can Tho, Vietnam using a choice experiment survey. The results were analyzed using a mixed logit model to determine consumers' preferences for sustainability and health traits in rice. Four price levels were used to elicit willingness-to-pay for four certification labels: low-emission, eco-friendly, ethically produced, and low glycemic index rice. By separating the components that make up the concept of sustainability and by including a label related to personal health and diet preferences, we are able to gain an understanding of the value consumers place on attributes that benefit the common good vs. attributes that benefit the individual consumer.ResultsThe results showed that consumers were willing to pay a price premium for all certification labels, with the highest marginal utility assigned to low glycemic index rice.DiscussionCertification of eco-friendly and ethical production generated similar utility levels, while low-emission rice was valued lower, although it still fetched a significant price premium compared to the status-quo option of rice with no certifications. The results of this study can help policymakers and value chain actors develop rice value chains that integrate sustainable production practices as well as foster the nutrition and health of rice consumers.

The dataset was generated from a choice experiment to explore consumers’ preferences and willingness to pay for rice sustainability and health certification labels.

Vietnam is supportive of the transition to sustainable rice production in the Mekong Delta. The national program promoted best management practices for rice production through “1 Must Do and 5 Reductions” (1M5R). This review traces the technological development and uptake of 1M5R in national policies and by end-users. We highlight the outcomes from various policy-supported initiatives and unpack plausible pathways that generated the widespread adoption of 1M5R in eight provinces in the Mekong River Delta: at least 104,448 smallholder rice farmers were reached, and 1M5R practices adopted on 113,870 hectares. The scaling of 1M5R was enabled through a convergence of different socio-technical systems with varied foci, including sustainability certification, contract farming, consolidation of production, and improved use of inputs, aside from the development of sustainable technologies. In addition, 1M5R was promoted with incentives generated by a World Bank project and other initiatives in line with a national policy of increasing the quality of rice production for national and international markets. The interconnections of varied socio-technical systems, enacted by different intermediaries, catalyzed the spread of 1M5R. The widespread adoption by smallholder farmers increased their profits and raised awareness across diverse stakeholder groups of the higher marketability of rice produced with sustainable practices.

The Paris Agreement, adopted in December 2015 at the 21st session of the Conference of Parties to the United Nations Framework Convention on Climate Change (UNFCCC), is the first legally binding document for all Parties to address climate change (UNFCCC, 2015). This is reflected in the nationally determined contributions (NDCs) of Parties. Although previous agreements on climate change had been reached, the Paris Agreement marked a new era where all countries will have the same transparency requirements for their greenhouse gas (GHG) emissions reporting from 2020 onwards. These universal requirements provide increased accountability on the steps countries are taking towards implementing the emission reduction goals set forth in their NDCs.