It isn’t easy to get farmers to buy into cutting greenhouse gas emissions and other climate action goals, especially when this requires investing in new machinery (Happy Seeders, balers and straw choppers to manage and not burn crop stubble) or results in yield loss (replacing urea with organic fertilisers).
The difficulty is more in countries like India, which has over 86% farmers with small or marginal holdings of 2 hectares (5 acres) or less. That’s where transformative “low effort, high impact” agricultural practices can make a difference. One such practice, specific to rice cultivation, is Alternate Wetting and Drying (AWD).
Conventional rice farming involves preparing nurseries where the paddy seeds are sown and raised into young plants. These seedlings are then uprooted and replanted 25-30 days later in the main field, which is about 10 times that of the nursery seedbed area.
The normal crop duration after transplantation is 90-100 days, going up to 120 days and more in some varieties. Over a typical 90-100-day cropping period, the field is kept under flooded conditions for the first 65 days or so.
The continuous flooding – maintaining a water depth of 4-5 cm – is done mainly to suppress weeds. The standing water creates an anaerobic environment, depriving the weed seeds of oxygen to germinate and grow. The need for such flooding reduces after 65 days, when the paddy crop’s vegetative growth and tillering stage is completed, and the panicles (flower clusters from which the grains develop) start forming inside the stem.
While flooded paddy fields help control weeds, the resultant anaerobic (oxygen-free) soil environment is also suitable for methanogenic microbes – archaea and bacteria – that decompose the plant organic matter. This reaction, of the carbon from organic matter with hydrogen from water, ends up producing methane.
Methane is a potent greenhouse gas, with 28 times the global warming potential of carbon dioxide (CO2) over 100 years.
Under AWD, the paddy fields, instead of being kept constantly flooded, are periodically dried out before re-flooding. The idea is to disrupt the waterlogged anaerobic conditions conducive to methane-producing microbes.
“We tell farmers to flood their fields for the first 20 days. But for the next 45 days (from the 21st to the 65th), they should dry it out for 12 days. We recommend two such dry-downs of six days each (for draining out the water to 10-15 cm below the soil surface) within the 45-day window,” says Devdut Dalal, co-founder of Mitti Labs Ltd.
The Bengaluru-based climate-tech startup conducted a detailed study to quantify the water savings, methane emissions reduction and grain yields from AWB during the 2024 kharif (monsoon) cropping season. It covered 30 farmers’ fields across three supersites (villages) in the Warangal district of Telangana. Paddy was grown through the AWDcmethod in 15 of these fields and through traditional continuous flooding (CF) in the other 15.
The Mitti Labs study found the average water consumption to be only 3.14 million litres per acre in the AWD fields, as against 4.96 million litres for CF. The average methane emissions, likewise, worked out to 3.5 tonnes of CO2 equivalent per hectare (1.4 tonnes per acre) from AWD, compared to the baseline number of 6 tonnes (2.4 tonnes/acre) in CF paddy cultivation.
More importantly, from a farmer’s perspective, the average grain yield was the same, roughly 2.5 tonnes per acre, under both AWD and CF. “AWD is like turning off the tap while brushing your teeth. It is a low-effort, yet highly effective method of conserving water and mitigating climate change without affecting crop yields,” Dalal points out.
However, Dalal is eyeing AWD’s potential beyond that – how it can be used as a source for farmers to earn carbon credits.
In 2023-24, Mitti Labs signed up with 850 farmers – 600 from Telangana and 250 from Andhra Pradesh – for them to implement AWD, alongside installing 30-cm-long perforated pipes (to monitor water table depths) and closed acrylic chambers (to collect gas samples for measuring methane emissions) in their fields.
An acrylic chamber to measure methane emissions, installed in a rice field in Telangana. (Special arrangement, Mitti Labs)
The number of farmers onboarded rose to 11,300 (Telangana: 6,000, AP: 4,000, Odisha: 800 and Tamil Nadu: 500) in 2024-25 and further to 69,000 (Telangana: 35,000, AP: 25,000, Odisha and TN: 4,000 each, and Karnataka: 1,000) in 2025-26, over both the kharif and rabi (winter-spring) crop seasons.
“We are seeking to generate methane emissions data based on direct measurement, through placement of chambers in individual farmer fields and sending the samples collected in vials to accredited laboratories for gas chromatography analysis. Such real, verified and location-specific reductions (in CO2 equivalent) can be used as carbon credits for sale in domestic and international markets,” explains Dalal.
The buyers of carbon credits are data centre operators, airlines and other massive energy- and water-consuming industries. They purchase these credits in order to offset their own emissions and achieve “net zero-carbon” targets.
Mitti Labs claims to have combined direct measurement with geo-tagging and boundary mapping of fields (to enable remote sensing and high-resolution satellite imagery) for building “the most robust digital monitoring, reporting and verification systems for rice agriculture in the world”. And with the maturing of carbon markets, it also allows farmers to monetise their methane reductions.
Carbon credits from methane abatement are now trading at $15-25 dollars per tonne of CO2 equivalent. At 2.5 tonnes (6 minus 3.5) per hectare, a single paddy crop can, thus, generate at least $37.5 of carbon credit. That, at current exchange rates, translates into Rs 3,367 per hectare or Rs 1,363 per acre – not an insignificant amount.
While Mitti Labs is planning to ramp up to 300,000 farmers in the next two years, it isn’t alone. The Good Rice Alliance – a partnership of the German life sciences major Bayer with Shell Energy India and Singapore’s Tamasek-owned GenZero investment platform – is promoting paddy cultivation through both AWD and direct seeding of rice (which bypasses nursery preparation and transplanting).
The alliance claims to have enrolled 12,000-plus farmers across 13 states, covering 35,000 hectares and reducing methane emissions equivalent to around 120,000 tonnes of CO2 per year.
Clearly, this is a field that’s opening up – and in a crop where India is today the world’s top producer, as well as exporter.