Alternate Wetting and Drying (AWD) for Sustainable Paddy Cultivation in India
In recent years, the alternate wetting and drying (AWD) technique has emerged as a high-potential sustainable paddy cultivation method. It reduces water usage, labor costs, and greenhouse gas emissions. This blog is on the AWD practice, benefits, and potential.
Anil is a paddy cultivator in the Mukundapuram Gram Panchayat of Nidamnoor Mandal, Nalgonda (Telangana). He depends on rainfed irrigation to cultivate his two-acre land and was left unprepared to start sowing with the early onset of monsoon in Kharif. With climate change resulting in irregular rainfall patterns every year, traditional methods of cultivating rice prove challenging as they require preparation of land and nursery prior to sowing. Also, traditional methods need a huge amount of water and higher investment in labor making them unsustainable. Paddy being a major crop in India thus necessitates larger adoption of sustainable paddy cultivation practices like Alternate Wetting and Drying.
Alternate Wetting and Drying:
Alternate Wetting and Drying (AWD) is a water management technique for paddy cultivation that involves intermittent irrigation. The AWD method involves applying water to the paddy fields intermittently, where the fields are flooded and drained alternately. In this method, the water level in the field is allowed to fall to a 15-20 Centimetres level in the subsoil before the next irrigation event. This process is repeated throughout the cropping season.
AWD has been found to be effective in reducing water consumption in paddy cultivation. Studies have shown that AWD can reduce water consumption by up to 30% compared to the conventional continuous flooding (CF) method of irrigation. The AWD method has also been found to improve the yield of paddy crops in some regions.
Alternate Wetting and Drying and Greenhouse Gas Emissions:
Paddy cultivation is a major source of greenhouse gas emissions, particularly methane (CH4). Methane is produced in the anaerobic environment created in the paddy fields during the cultivation process. Methane emissions from paddy fields are estimated to account for about 10% of global greenhouse gas emissions. In India, paddy cultivation alone is responsible for 20% of the country’s methane emissions.
AWD has been found to be effective in reducing greenhouse gas emissions from paddy fields. Studies have shown that the AWD method can reduce methane emissions by up to 50% compared to the conventional continuous flooding method. It is estimated that AWD reduced methane emissions by 45% compared to the continuous flooding method.
The reduction in methane emissions with AWD is due to the intermittent drying of the paddy fields, which creates aerobic conditions that inhibit methane production. The AWD method also reduces the amount of organic matter in the soil, which further reduces methane production.
Alternate Wetting and Drying and Yield:
The AWD method has been found to improve the yield of paddy crops in some regions. Studies have shown that the AWD method can improve the yield of paddy crops by up to 20% compared to the conventional continuous flooding method.
Our teams introduced the AWD method to Anil and many farmers in the region who were upset with the early onset of rains. Anil used our Drum Seeder to sow seeds directly into the unpuddled land filled with rainwater. He also adopted appropriate agronomic practices in weed, nutrient, and pest management throughout the season, including using our drone spraying intervention for better efficacy. The yield was 5 quintals/acre higher than in conventional practice and he got an additional income of Rs.40, 000.
The improvement in yield with the Alternate Wetting and Drying technique is due to several factors. First, the intermittent drying of the fields allows the roots of the paddy plants to access oxygen, which promotes their growth. Second, the AWD method reduces the incidence of diseases that thrive in flooded conditions. Third, the AWD method reduces the amount of water that the paddy plants absorb, which can lead to higher nutrient uptake and more efficient use of fertilizers.
Potential for AWD Adoption in India:
The adoption of AWD in India has been slow, despite its potential to reduce water consumption and greenhouse gas emissions and improve crop yields. The main barriers to AWD adoption in India are the lack of awareness and technical knowledge among farmers.
Decentralized methods that promote the faster transfer of knowledge and adoption through enabling community ownership like lead farmer platforms can hold the key to promoting this technique. We have implemented AWD in combination with Direct Seeding of Rice (DSR) on 5,450 Acres in the Kharif and Rabi Seasons of 2022-23 using our farmer-to-farmer extension model. It has resulted in an estimated 94.5 Lakh Kilo Litres water savings!