Alternate wetting and drying

[2] However, nowadays farmers follow a ‘safe’ AWD in which they maintain the 15-cm subsurface water level threshold for re-flooding.

[3] This method has become a recommended practice in water-scarce irrigated rice areas in South and Southeast Asia.

In the Philippines, the adoption of safe AWD started in Tarlac Province in 2002 with farmers using deep-well pump systems.

After the irrigation in the crop field, the water depth gradually decreases because of evapotranspiration, seepage, and percolation.

After flowering, during the mid-season and late season (grain filling and ripening stages), the water level is allowed to drop below the soil surface to 15 cm before re-irrigation.

To suppress the growth of weeds in the rice field, AWD method should be followed 1–2 weeks after the transplantation.

[11] AWD leads to firmer soil conditions at harvest, which is suitable to operate machines in the field.

This method has been assumed to reduce CH4 emissions by an average of 48% compared to continuous flooding in the 2006 IPCC methodology.

Alternate wetting and moderate soil drying reduce cadmium accumulation in rice grains.

High weed growth rate in the crop field is a major problem from the farmers' point of view.