The United Nations Sustainable Development Goals that are applicable to this technology.

Goal 1: no poverty

AWD reduces irrigation costs (fuel, labor, water fees), helping smallholder farmers lower production expenses and improve net income, especially in pump-irrigated systems.

Goal 2: zero hunger

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.

Goal 6: clean water and sanitation

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.

Goal 12: responsible production and consumption

AWD encourages efficient resource use—especially water and energy (fuel/electricity for pumps)—and supports sustainable rice intensification.

Goal 13: climate action

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:

Step 1: Field Preparation and Crop Establishment

1. Level the Field: Ensure the rice field is well-leveled. Good leveling is critical for efficient irrigation and prevents some areas from becoming excessively dry or wet, which could negatively affect yields.
2. Construct Strong Bunds: The field must be surrounded by strong bunds (field boundaries) to hold water and prevent seepage.
3. Start as Conventional Flooding: Transplant or sow the rice crop as normal. Initially, maintain a layer of standing water (e.g., 3–5 cm, gradually increasing to 10 cm as the crop establishes).
4. Manage Weeds (If Necessary): If heavy weed pressure is expected, maintain continuous flooding for the first 2–3 weeks after transplanting (or until direct-seeded rice is about 10 cm tall) to suppress weed growth before starting the AWD cycles.

Step 2: Construct and Install the Field Water Tube

The field water tube is the key tool used to monitor the water level below the soil surface.

1. Make the Tube: Obtain a piece of plastic PVC pipe (often about 4 inches or 15 cm in diameter) or bamboo, about 30–40 cm long.
2. Perforate the Tube: Drill or punch several small holes (e.g., 0.5 mm in diameter, spaced 2 cm apart) around the lower 15 cm of the tube. The upper 15 cm of the pipe should remain unperforated.
3. Install the Tube: Push the tube vertically into the paddy soil until about 20 cm remains above the soil surface. The bottom of the tube should be below the plow pan.
4. Clear the Inside: Remove any soil or mud inside the tube so you can clearly see the water level relative to the soil surface inside the tube.
5. Placement: Place the tube in a flat, representative spot in the field, preferably near a bund for easy monitoring access (but not less than 1 meter away from the bund).

Step 3: Initiate and Manage the Wetting and Drying Cycles

AWD cycles typically start about 15 days after sowing (DAS), or one to two weeks after transplanting, once the crop roots are established.

1. Initial Flooding: Irrigate the field to flood it as usual, to a depth of about 5–10 cm of standing water.
2. Allow Drying: Stop supplying water and allow the field to dry naturally. The standing water will disappear, and the water level inside the tube will gradually drop due to infiltration and evapotranspiration.
3. Monitor Daily: Observe the water level inside the tube daily.
4. The "Safe AWD" Rule (The Trigger): Do not irrigate again until the water level inside the tube has dropped to 15 cm below the soil surface. This 15 cm level is considered the "safe AWD" threshold because research has shown it prevents drought stress and will not cause a yield decline. Depending on the soil type and weather, reaching this 15 cm threshold typically takes between 1 and 10 days.
5. Re-Irrigate: Once the 15 cm threshold is reached, irrigate the field to raise the water level back up to approximately 5 cm of standing water.
6. Repeat the Cycle: Repeat steps 2 through 5 throughout the growing season. If rainfall occurs, it should be absorbed by the dry soil, delaying the need for the next irrigation event.

Step 4: Manage Water During Critical Stages

During the most sensitive stage of rice growth, continuous flooding must be temporarily maintained to protect the crop and secure the yield.

1. Keep Flooded at Flowering: For approximately two weeks, starting one week before and continuing until one week after the flowering stage (panicle heading), the field should be kept shallow-flooded continuously at about 5 cm depth. This period corresponds roughly to 55–75 days after transplanting for most varieties.
2. Resume AWD: After this critical reproductive stage, you can resume the normal AWD cycles (allowing the water level to drop to 15 cm below the soil surface before re-irrigating) during the grain-filling and ripening stages.

Step 5: Pre-Harvest Drainage

1. Final Dry-Down: As is standard practice in rice farming, stop irrigation 1–2 weeks before the planned harvest date. This allows the field to dry out completely, which facilitates harvesting and helps improve grain moisture content.

Important Co-Management Considerations

• Fertilizer Timing: Nitrogen fertilizer (like urea) shoul

Downloads

• Field water management and irrigation practices in rice production in West Africa.pdf (PDF, 1.69 MB)
• Increasing lowland rice yields of smallholder farmers through the adoption of good agricultural practices in the forest agro-ecological zone of Ghana.pdf (PDF, 1.38 MB)
• Alternate wetting and drying in irrigated rice.pdf (PDF, 467.44 KB)