Jiban Krishna Biswas
As an agricultural country, Bangladesh encounters a noteworthy challenge in feeding its ever-increasing population with rice. The boro rice occupies 5 million hectares, providing the highest portion of the total production, and is mainly grown under irrigated conditions prone to emitting the greenhouse gas (GHG) methane. Livestock rearing is also a significant source of both methane and nitrous oxide, both of which are significant in terms of global warming potential. Compared to rice and livestock, the contribution of aquaculture to emitting GHG is still low, but the contribution of this sub-sector cannot be avoided, as aquaculture is increasing at a significant rate. So, the real challenge of the day is to satisfy the appetites of hungry millions while minimising GHG.
Rice and the Methane Challenge
The rice crops grow all over the year as aus, aman and boro over a total coverage of around 12 million hectares. The Boro rice crop, entirely irrigated as I mentioned and is typically kept submerged in the field throughout the growing season. The other two rice, aus and aman, are supposed to be rainfed, but the farmers do not rely on rain, as most of the varieties are high-yielding types. They are supposed to irrigate their crop as and when necessary. An irrigated rice crop is supposed to release around 24 MtCO₂e per year. So, farmers are using a huge amount of water (75% of available fresh water) to grow rice. In conventional irrigation methods, 3–5 thousand litres of water are needed to grow a kilogram of rice.
But in reality, 1500–2000 litres of water are enough to grow a crop without affecting yield. That is why scientists have introduced a method called alternate wetting and drying (AWD), where the field is frequently allowed to dry to a certain extent until there is scarcity of water in the root zone. This method can save approximately 30 per cent of water and can also save approximately 15% on irrigation costs. Moreover, frequent drying during the crop’s vegetative period reduces methane emission. It’s a proven technology, yet farmers are still afraid to accept that, as they still think that more water means more yield. In addition to that, there are still some more socio-economic reasons, like flat-rate water pricing, pump owner-farmer relationships, etc.
Beyond Rice: Diversifying the Cropping System
To achieve self-sufficiency in rice, the importance of other crops grown under upland conditions was overlooked. If 5–10 per cent of the irrigated rice land can be converted to upland crops like wheat, pulses, and oil crops, a significant reduction in methane emissions can be achieved. Another method to reduce GHG, mainly nitrous oxide, is to practise deep placement of urea (UDP) briquettes or application of prilled urea by a special BRRI-designed machine. Selecting an appropriate cropping pattern with any upland (rainfed) crops may also be a viable option to reduce methane emissions. Even the rainfed direct seeded rice grown under rainfed conditions (real aus) can be useful to reduce methane emission.
Livestock: The Silent Methane Giant
Livestock contributes around half of the methane emitted from the agricultural sector. Enteric fermentation from 24 million cattle is the main source. In addition to that, millions of goats and poultry make some contribution. The ruminants produce around 30.124 MtCO₂e of methane annually, while manure adds another 2.5 Mt. Poor manure management and storage emit a huge amount of nitrous oxide (37.242 MtCO₂e/yr). Therefore, improved feeding management with balanced rations, digestibility enhancers, small biogas plants, and improved manure management practices can reduce both methane and nitrous oxide emissions (Das et al.,, 2020).
Aquaculture: Feeding People, Emitting Methane
Bangladesh has achieved a milestone of producing 5 million metric tonnes of fish a year from aquaculture, meeting most of the animal protein needs. But growing fish in ponds is also a source of methane. The amount of methane releases is expected to rise to 4.6 MtCO₂ by the end of 2025. The quality feed and organic matter build-up in low-aerated ponds favour the activation of methane-producing microorganisms. The aeration through artificial aerators and improved feed management reduces methane reduction. In capturing fish, energy-efficient boats and renewable energy during fishing or post-harvest processing can help reduce methane emissions.
IFAD and RAMP: A Timely Intervention
The International Fund for Agricultural Development (IFAD) is an established partner and has already invested USD 1 billion in Bangladesh since 1978. Its latest interest is in climate-resilient agriculture devoted to methane reduction. IFAD initiated the Reducing Agricultural Methane Programme (RAMP), supported by the Global Methane Hub and the US State Department, in 2013. This RAMP’s attention towards Bangladesh is timely and praiseworthy. RAMP can supports Bangladesh in three areas:
Policy alignment: align the methane reduction program with the country’s climate pledges.
Pilot projects: Expansion of AWD, UDP, better livestock feeding, and sustainable aquaculture.
Human resource development: Knowledge sharing and training, Gender equity and empowerment, establishing a digital MRV (Measurement, Reporting and Verification) network, and linking farmers to the global carbon mechanism market.
Conclusion
The agriculture in Bangladesh is at a turning point. The paddies, pastures and ponds are the parts for our survival for our existence on one hand, on the other hand, they are one of the causes of heating the earth. So, what we need to maintain a balance among food security, climate resilience, and sustainable development. It is more than meeting the target. It is fertile soil, reliable eater and safe harvest for the generation to come. I believe RAMP, under the care of IFAD, would help to control emissions to a tolerable level.
The writer is a Senior Technical Consultant of Reducing Agricultural Methane Programme of the Asia and the Pacific Division at International Fund for Agricultural Development
