AWD – a water-saving method that cuts paddy irrigation costs by 20–25%

Infographic: TBS

At present, producing one kilogram of rice requires approximately 1,500 to 1,600 litres of water during irrigation, most of which is extracted from underground through pumps. However, if the alternate wetting and drying (AWD) irrigation method is applied, the water demand reduces by around 200 litres, researchers at the Bangladesh Rice Research Institute (BRRI) have observed.

The water-efficient AWD method can save irrigation water by up to 25%, thereby slashing costs by 20-25%, and at the same time boost rice yield by 3-10%, they say.

In AWD, a paddy field is made wet and dried intermittently, meaning watering only when necessary. 

In the method, a 3x10-inch perforated plastic pipe is placed vertically in the field, with six inches buried underground. Farmers can monitor the water table through the pipe and irrigate when needed. 

Talking to TBS, Dr Md Mahbubul Alam, chief scientific officer for irrigation and water management at BRRI, pointed out that paddy farming needs huge volumes of water. "Nearly 80% of irrigation water is sourced from the underground during Boro season." 

Talking about AWD, he said the method also benefits farmers economically. 

"It has been tested across the districts under Rajshahi, Rangpur, Sylhet, Khulna, and Barishal divisions."

Dr Alam said the method requires minimal investment. 

Each pipe costs between Tk100-130, and three pipes are enough to monitor irrigation on a one-acre field. As such, production costs can be reduced by 15-20% as irrigation remains one of the largest expenses, he explained.

AWD has already gained traction in some parts of the country. Both governmental and non-governmental organisations are working for its promotion among farmers.

In Kaliganj upazila of Jhenaidah, over 1,000 farmers have applied the method to paddy farming.

Kamalesh Sharma, a farmer in Kurulia village of the upazila, has been using AWD for the past three years.

He shared with TBS that this season he has irrigated his three-acre Boro field 60 times. But before applying AWD, it needed 70–80 irrigations each year. 

He said the power consumption for irrigation has also been reduced. The monthly electricity bill for April has come down to Tk10,000 from Tk13,000 in years without AWD.

A local NGO, Sonar Bangla Foundation, is actively promoting AWD in Kaliganj. 

Its Executive Director, Shibu Pada Biswa,s said previously they provided farmers with pipes, but now many are buying them themselves.

Another farmer in the upazila, Abdur Rashid from Sundarpur village, said, "Earlier, I had to irrigate the field every other day. Now it's every 3–4 days."

AWD also contributes significantly to curbing greenhouse gas emissions.

Mozammel Haque, senior scientific officer at BRRI for soil science, told TBS that the estimated methane emissions from paddy fields in the country are around 1.39 to 1.56 million tonnes annually, which can be curbed by 25-30% with the use of AWD in irrigation.

Bangladesh uses nearly 20,000 million cubic metres of groundwater during the Boro season alone. BRRI researchers say if 10 lakh hectares were brought under AWD, the saved water could be used to cultivate Boro on an additional 2 lakh hectares.

However, there are challenges to implementing AWD on a larger scale. 

Dr Jiban Krishna Biswas, rice scientist and former director general of BRRI, said the biggest obstacle is the existing irrigation pricing system. "The charges are seasonal, where the farmer has to pay the full amount for the season, regardless of the volume of water consumption." 

He highlighted the need for governmental policy reforms in this regard.

Currently, the International Fund for Agricultural Development (IFAD) is promoting pilot activities on AWD under a programme against methane emissions in agriculture. 

IFAD Bangladesh Director Valantine Achancho told TBS that rice production remains a major source of methane emissions in Bangladesh due to the country's irrigated paddy farming.

Promoting AWD practices is essential to enhancing the resilience of rural communities, advancing Bangladesh's climate agenda, and securing a more sustainable future for its agricultural sector, he stressed.