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https://taat.africa/gov/technologies/awd-alternate-wetting-and-drying-irrigation-system
Dry Out the Methane. Green Up Your Harvest.
Alternate Wetting and Drying is a scheme-ready water-management protocol that replaces continuous flooding with controlled wet–dry cycles triggered by a defined subsurface water level. It raises water productivity, allowing the same water to cover more area or more farmers, while maintaining yields. The practice also reduces methane emissions from rice paddies, supporting national climate targets, and is low-cost to integrate into irrigation scheduling and extension packages.
This technology is not yet validated.
| Target groups | Positive impacts |
| Women rice farmers & female-headed households | Benefit from reduced irrigation labor and more predictable schedules, easing time pressure and helping manage household and farm duties simultaneously. |
| Downstream (tail-end) canal-irrigated farmers | Gain more reliable water access when AWD reduces upstream overuse, leading to more equitable irrigation and stable yields. |
| Pump-irrigated smallholders (men & women) | Save fuel and labor as AWD reduces water use and pump runtime by 20–30%, directly lowering production costs. |
| Climate-conscious or sustainability-focused rice growers | Reduce methane emissions (up to 50%) and qualify for carbon credits or green certification schemes, potentially increasing income and market access. |
| Farmers in drought-prone or water-scarce areas | Maintain yields using 20–40% less water, helping them adapt to water shortages and reduce dependency on unreliable rainfall or depleted water tables. |
Climate adaptability: Highly adaptable
AWD promotes efficient water use by reducing irrigation needs by 25–40%. In irrigation schemes, this enables more farmers to access water or to cultivate larger areas. This makes AWD a practical adaptation strategy in contexts facing water scarcity or irregular rainfall due to climate change.
Farmer climate change readiness: Significant improvement
AWD helps irrigated farmers adjust to reduced water availability by allowing flexible, controlled irrigation cycles. It stabilizes yields under moderate drought stress and supports water-use efficiency, enhancing farmer resilience to climate variability.
Carbon footprint: Much less carbon released
AWD significantly reduces methane emissions (CH₄) from irrigated rice fields—often by 30–70%—by introducing aerobic periods into the soil. These aerobic phases disrupt the anaerobic conditions that favor methane-producing microbes, making AWD one of the most effective low-emission practices in rice farming.
Environmental health: Moderately improves environmental health
While not always measured directly, AWD can improve environmental health by reducing methane emissions and lowering water usage, which indirectly supports groundwater sustainability. However, risks such as increased nitrous oxide emissions or nitrate leaching should be monitored and managed.
Soil quality: Does not affect soil health and fertility
AWD does not typically degrade or improve soil structure or fertility under proper use. However, improper management (e.g., excessive drying) may lead to nutrient loss or heavy metal mobilization. With correct thresholds, soil quality remains stable.
Water use: Much less water used
The use of the AWD reduces irrigation water use in rice by 25–40%, depending on soil type and water control infrastructure. This contributes to water conservation in both surface and groundwater systems, making it a highly efficient irrigation method.AWD method reduces the irrigation water need in Rice by at least 25%
Insufficient water to serve all farmers/hectares: Current schemes cannot cover demand in dry periods under continuous flooding.
Over-extraction and stress on canals/groundwater: Continuous flooding accelerates withdrawals beyond sustainable limits.
Agricultural methane undermining climate targets: Rice methane is a large share of sector emissions and needs practical mitigation.
High public spending on irrigation energy: More water pumped means higher subsidies or public power costs.
Inconsistent, non-standard water management: Lack of a simple protocol reduces scheme efficiency and complicates extension. (AWD is codified in technical guidance and standards.)
Alternate Wetting and Drying (AWD) is a climate-smart practice that delivers triple benefits: it significantly reduces methane emissions (by $30-70%$) and conserves water (by $15-30%$). These outcomes strongly advance Climate Action (SDG 13) and Clean Water (SDG 6). Furthermore, the practice increases net farmer income (supporting No Poverty, SDG 1) and is gender-friendly, offering critical opportunities to empower women farmers through specialized training and inclusion in water management decisions.
To successfully incorporate AWD technology, project design must focus on institutional support, technical scaling, and financial incentives.
Project activities should logically begin by creating a supporting environment and then scaling up technical implementation:
Projects must first establish the necessary political and regulatory foundation. This involves supporting the issuance of national strategies and implementation plans for water-saving and low-methane rice production. Crucially, formal coordination mechanisms must be institutionalized between agriculture/extension and water resource management sectors.
Technically, projects must develop and issue integrated technical standards for the co-management of water, crop residues (straw), and fertilizer. Furthermore, existing water-saving irrigation quotas for rice production need to be updated to incentivize reduced water use, moving away from traditional continuous flooding quotas.
This framework should be supported by piloting market mechanisms, such as carbon trading (for monetizing methane reduction) and water rights trading or buy-back schemes, to provide additional financial incentives for adoption. Finally, a robust Monitoring, Reporting, and Verification (MRV) system must be adopted, using both remote sensing and in-situ measurements, to track GHG emission reductions and water practices accurately.
Once the policy foundation is set, the focus shifts to field implementation and knowledge transfer. This requires investing in enabling infrastructure, including the modernization and rehabilitation of on-farm irrigation and drainage systems, small water storages, and executing land leveling. These improvements ensure the flexible and reliable water delivery essential for AWD.
Next, systematic training programs must be implemented for all farmers (including women) on the full low-methane package solution, encompassing AWD, optimal fertilizer use, and straw management. These training efforts should utilize demonstration farmlands and on-farm learning schools to visually demonstrate AWD’s effectiveness and build farmer confidence. Critically, the project must provide targeted gender training and leadership skills for women farmers to actively promote their inclusion in water management organizations.
To maximize the dual benefits of water saving and GHG mitigation, projects should promote the integrated "Water-Straw-Fertilizer Co-management" package.
The Field Water Tube is the essential core tool for monitoring. It is a simple perforated tube that is pushed into the soil. The key action is to re-irrigate only when the water level inside the tube drops to 15 cm below the soil surface, which is the "safe AWD" threshold proven to prevent yield loss.
Optimized Water Timing ensures both yield protection and environmental benefit. Continuous shallow flooding must be maintained during the critical flowering stage (about one week before to one week after panicle heading) to prevent yield loss. To maximize reduction and enhance root development, drying periods must be implemented at the early growth stage and late tillering stage.
Straw Management is crucial for climate impact. Projects should promote deep returning of straw residues (burying depth over 15 cm) combined with the AWD early-stage drying period. This practice facilitates aerobic decomposition of fresh straw, which is crucial for reducing methane emissions.
Fertilizer Management focuses on efficiency and reducing nitrous oxide emissions. Nitrogen fertilizers should be applied to the dry soil just before re-irrigation. Promoting organic materials (compost, biogas slurry) enhances soil fertility and reduces reliance on chemical fertilizers.
Weed Control is required because drying periods can favor weed germination. Farmers should maintain initial flooding for 2–3 weeks after transplanting/sowing before beginning the AWD cycles to suppress weeds. For large-scale monitoring and management, digital sensors, IoT devices, or ICT tools like RiceAdvice Lite can be employed to track water levels and provide site-specific nutrient recommendations.
Scaling AWD requires broad collaboration across sectors:
Technical Partners must anchor the project with sound science. The International Rice Research Institute (IRRI) provides the core technology and protocols, while the Africa Rice Center (AfricaRice) validates AWD for regional environments. National Agricultural Research and Extension Services (NARES) are vital for local adaptation of standards and direct farmer training.
Governmental Partners must provide the regulatory and infrastructural backbone. Agriculture Ministries/Departments lead on policy and extension, while Water Resource Agencies are critical for coordinating flexible irrigation services and implementing water pricing/rights reforms. Environmental Agencies play a role in establishing MRV systems and carbon frameworks.
Community and User Groups are crucial for on-the-ground implementation. Water User Associations (WUAs) and Farmer Cooperative Organizations are essential for the collective implementation of AWD and ensuring the sustainable operation and maintenance of shared systems. Local Women's Federations/Groups are necessary to deliver targeted training to women and enhance gender inclusion in water management decisions.
Financial and Private Sector Partners provide resources and market links. Development Banks (e.g., World Bank, AfDB) provide financing and support institutional reforms. Agribusinesses and Millers can integrate AWD into their supply chains for sustainable sourcing. Finally, Carbon Finance Entities (like Gold Standard) help pilot projects monetize methane reductions into carbon credits.
Effective communication is vital to overcome the farmer's skepticism, often associated with allowing rice fields to dry.
The most powerful tools are visual proof and practical aids. Demonstration Farmlands/Plots should be set up to visibly compare AWD to conventional flooding, proving that AWD maintains yield while saving water. The Field Water Tube serves as a simple physical communication tool, giving farmers direct visual assurance that the rice plants are accessing water below the surface, confirming the practice is "safe" for their yields.
For knowledge dissemination, projects should distribute Simple Pictorial Guides and Fact Sheets in local languages for easy knowledge transfer. Technical Bulletins/Manuals offer detailed guidance for training extension agents and project staff.
To reach a wide audience, Public Awareness Campaigns should utilize radio, TV, and social media to disseminate technical advisories and feature successful farmers (including women). Mobile Applications (like Rice Crop Manager) provide adaptive, site-specific advice on fertilizer and water timing.
Finally, incentive messaging is critical for driving adoption. Projects must provide clear Economic Analysis and Case Studies that document the financial benefits, such as high Return on Investment and reduced fuel/water fees, which motivate farmers by showing tangible financial returns.
Water use reduction
Greenhouse Gas Emissions Reductions
Open source / open access
Scaling Readiness describes how complete a technology’s development is and its ability to be scaled. It produces a score that measures a technology’s readiness along two axes: the level of maturity of the idea itself, and the level to which the technology has been used so far.
Each axis goes from 0 to 9 where 9 is the “ready-to-scale” status. For each technology profile in the e-catalogs we have documented the scaling readiness status from evidence given by the technology providers. The e-catalogs only showcase technologies for which the scaling readiness score is at least 8 for maturity of the idea and 7 for the level of use.
The graph below represents visually the scaling readiness status for this technology, you can see the label of each level by hovering your mouse cursor on the number.
Read more about scaling readiness ›
Uncontrolled environment: tested
Common use by projects connected to technology providers
| Maturity of the idea | Level of use | |||||||||
| 9 | ||||||||||
| 8 | ||||||||||
| 7 | ||||||||||
| 6 | ||||||||||
| 5 | ||||||||||
| 4 | ||||||||||
| 3 | ||||||||||
| 2 | ||||||||||
| 1 | ||||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | ||
| Target groups | Positive impacts |
| Women rice farmers & female-headed households | Benefit from reduced irrigation labor and more predictable schedules, easing time pressure and helping manage household and farm duties simultaneously. |
| Downstream (tail-end) canal-irrigated farmers | Gain more reliable water access when AWD reduces upstream overuse, leading to more equitable irrigation and stable yields. |
| Pump-irrigated smallholders (men & women) | Save fuel and labor as AWD reduces water use and pump runtime by 20–30%, directly lowering production costs. |
| Climate-conscious or sustainability-focused rice growers | Reduce methane emissions (up to 50%) and qualify for carbon credits or green certification schemes, potentially increasing income and market access. |
| Farmers in drought-prone or water-scarce areas | Maintain yields using 20–40% less water, helping them adapt to water shortages and reduce dependency on unreliable rainfall or depleted water tables. |
| Target groups | Unintended impact | Mitigation action |
| Women rice farmers & female-headed households | Increased weeding workload during dry intervals, since continuous flooding normally suppresses weeds. This often falls on women, who already manage both field and household labor. | Promote labor-saving options like pre-emergence herbicides, mulching, or group weeding days. Ensure women are involved in extension and have access to weed control tools. |
| Downstream (tail-end) canal-irrigated farmers | Water access inequality if upstream farmers don't follow AWD properly, drying fields too slowly or flooding continuously, leaving little water for downstream users. | Establish collective irrigation schedules and empower water-user associations to monitor compliance. Promote block-level AWD adoption to ensure synchronized water use. |
| Pump-irrigated smallholders (men & women) | Risk of crop stress or yield loss if AWD is misapplied (e.g., drying too long without proper reflooding). Farmers relying on pumps may over-dry to save fuel. | Train farmers on "safe AWD" thresholds using simple tools (e.g. perforated water tubes), and offer on-farm demonstrations to build trust in correct timing. |
| Climate-conscious or sustainability-focused rice growers | Higher nitrous oxide (N₂O) emissions from aerobic soil phases may offset methane savings, and food safety risks (e.g. cadmium uptake) may arise from dry cycles. | Encourage integrated nutrient management (split N application, organic inputs), and provide soil and grain testing where contamination risk is high. For carbon projects, ensure emission trade-offs are monitored and managed. |
| Farmers in drought-prone or water-scarce areas | Greater risk of nutrient leaching or mis-timed irrigation, especially where farmers lack technical support. Mismanagement can lead to yield loss or soil degradation. | Provide tailored training on AWD timing, soil moisture monitoring, and fertilizer management. Link AWD to broader climate-smart advisory services. |
| Target groups | Barriers | Mitigation action |
| Women smallholder rice farmers |
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| Downstream (tail-end) canal-irrigated farmers |
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| Pump-irrigated smallholder farmers |
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| Climate-conscious or sustainability-focused rice growers |
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| Farmers in drought-prone or water-scarce areas |
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| Country | Testing ongoing | Tested | Adopted |
|---|---|---|---|
| Côte d’Ivoire | –No ongoing testing | Tested | Adopted |
| Ghana | –No ongoing testing | Tested | Adopted |
| Nigeria | –No ongoing testing | Tested | Adopted |
This technology can be used in the colored agro-ecological zones. Any zones shown in white are not suitable for this technology.
| AEZ | Subtropic - warm | Subtropic - cool | Tropic - warm | Tropic - cool |
|---|---|---|---|---|
| Arid | – | – | – | |
| Semiarid | – | – | – | |
| Subhumid | – | – | – | |
| Humid | – | – | – | – |
Source: HarvestChoice/IFPRI 2009
The United Nations Sustainable Development Goals that are applicable to this technology.
AWD reduces irrigation costs (fuel, labor, water fees), helping smallholder farmers lower production expenses and improve net income, especially in pump-irrigated systems.
AWD maintains or slightly improves rice yields while saving water. It enhances resilience to drought and supports stable food production, especially in water-stressed areas.
AWD reduces water use by 25–40%, conserving irrigation water and reducing pressure on shared or limited water resources. It also promotes more equitable water access within irrigation schemes.
AWD encourages efficient resource use—especially water and energy (fuel/electricity for pumps)—and supports sustainable rice intensification.
AWD significantly reduces methane emissions from flooded rice fields (up to 70%), making it a key practice in low-emission rice farming strategies and NDCs (Nationally Determined Contributions).
AWD relies on monitoring the water level below the soil surface using a simple tool called a Field Water Tube.
Here is a step-by-step guide on how to use the AWD technique clearly and in detail:
The field water tube is the key tool used to monitor the water level below the soil surface.
AWD cycles typically start about 15 days after sowing (DAS), or one to two weeks after transplanting, once the crop roots are established.
During the most sensitive stage of rice growth, continuous flooding must be temporarily maintained to protect the crop and secure the yield.
Last updated on 14 November 2025
This technology can be used in the colored agro-ecological zones.
AWD: Alternate Wetting and Drying Irrigation System
https://taat.africa/gov/technologies/awd-alternate-wetting-and-drying-irrigation-system
Last updated on 14 November 2025, printed on 22 November 2025
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