Thailand: Innovative microorganisms to protect rice paddies from burning

IN BRIEF The practice of burn between sowing, quick and inexpensive, contributes to the toxic fog seasonal worker in Thailand. Rice farmers Chiang Rai, like Siriporn and Amnat Taidee, replace fire with microorganisms to decompose the straw. The product Soil Digest (five strains of Bacillus) reduces the decomposition time from ~30 days to 5–7 days. Observed effects: looser soil, yields rising (up to +20%) and a decrease in the need for fertilizer. The authorities are promoting these solutions;2,000 farmers are adopting the method on 100,000 in the province. Costs and logistics: private alternatives can be expensive (e.g. 1,200 baht for spraying drone); insufficient public stocks. Potential climate impact: estimated reduction of methane emissions rice paddies of at least 20%. Experts are calling for a transformation of the system: making aid conditional, facilitating access to machines and training for the 20 million Thai farmers.

Facing the clouds of toxic fog which stifle Thailand every year between January and Aprilfarmers are gradually giving up on burn to prepare their fields. In Chiang Rai, Siriporn and Amnat Taidee have adopted a microbial alternative — a product called Soil Digest developed locally using strains of Bacillus — and observe a ground more furniture, some yields increasing and reducing fertilizer needs. The solution accelerates straw decomposition, reduces the time before plowing, and can decrease the broadcasts linked to rice paddies, but its widespread adoption still faces cost and logistical challenges, despite incentive campaigns by authorities and the increasing use of drones for spraying.

Faced with the annual episodes of toxic fog caused in part by the burn Between plantings, Thai farmers are experimenting with microbial solutions that replace fire for decomposing straw and restoring soils. Products like Soil Digest, developed from local strains of Bacillusaccelerate the decomposition of residues in a few days, improve the structure of the groundreduce fertilizer needs and can increase yieldsAdoption is progressing, but scaling up still faces costs, limited stocks and the need to support farmers with material and educational assistance.

Context: Slash-and-burn agriculture, an entrenched practice and its consequences

The method of burn has long been perceived by many rice farmers as the quickest and cheapest way to prepare a field between two growing cycles. Between January and April, the combination of agricultural fires, forest fires, and industrial emissions—exacerbated by transboundary pollution—causes air quality in Thailand to plummet to dangerous levels.

To limit this phenomenon, Bangkok authorities have imposed restrictions on burning, but these measures have sparked tensions with farmers. According to environmental economist Witsanu Attavanich, the ban is putting a strain on farmers who feel they lack accessible alternatives.

Health and regulatory impacts

Recurring haze episodes trigger health alerts and prompt local governments to tighten controls. At the same time, policy proposals advocate linking public aid to the effective cessation of slash-and-burn agriculture, while also funding access to alternative tools and farmer training.

Concrete example: the Taidee couple and the microbial transition

In Chiang Rai, the couple Siriporn and Amnat Taidee illustrate the shift from a traditional practice to a microbial solution. Having replaced fire with microbial treatment, they have observed looser soil, reduced fertilizer costs, and… yields on the rise. For them, abandoning the “old way of doing things” has resulted in a tangible agronomic gain.

The change is not limited to their exploitation: in Chiang Rai province, approximately 2,000 farmers have adopted these solutions on the 100,000 farms in the province, a sign of growing interest in alternative practices.

The microbial solution: Soil Digest and its mechanisms

Developed by researcher Wichien Yongmanitchai, the product known as Soil Digest contains five strains of bacteria of the genus Bacillus, isolated locally. These microorganisms accelerate the decomposition of stubble and straw, reducing the time needed to soften the residues from nearly a month to 5–7 days.

The operation is based on enzymatic action and the stimulation of microbial activity in the soil, which promote the degradation of organic matter and contribute to the restoration of soil structure.

Observed agronomic and climatic effects

The tests conducted show yield gains of up to 20% for certain treated plots, as well as a potential reduction in emissions of methane rice paddies estimated at at 20%At the farm level, improving soil quality also makes it possible to reduce the use of chemical fertilizers.

Adoption, costs and logistical constraints

While the technology appears promising, its adoption faces obstacles. Local authorities encourage the use of these products, and the central government advocates for free access, but stocks are proving insufficient to meet demand.

On the private market, price can be a barrier for smallholders. In Pathum Thani, for example, one rice farmer spent 1,200 baht (approximately $37) to rent a drone and spray the Soil Digest on their plots. For some, the initial investment is justified by future savings on fertilizers and the sustainable improvement of the soil.

Support required

Experts emphasize that simply introducing a product is not enough; systemic change is needed, involving conditional subsidies, access to agricultural machinery (sprayers, drones, tillage equipment), and agricultural education programs. Nipon Poapongsakorn, an agricultural policy expert, recommends linking subsidies to concrete commitments to halt slash-and-burn agriculture and strengthening the dissemination of best practices.

Local production and expansion prospects

Professor Wichien has established a production unit in Samut Sakhon to manufacture his product using local strains, convinced that indigenous bacteria will be more effective in the Thai context. He aims to expand its use beyond Thailand to other regions of Southeast Asia, and even Africa, if he can secure production and logistics.

Operators are already using agricultural drones to spray these microbial solutions on stubble, accelerating the coverage of cultivated areas and reducing labor requirements.

Limitations, further research and recommendations

Independent experts consider the technology promising but emphasize that its effectiveness depends on all farming practices. Simply applying a product will not be enough to transform the practices of Thailand’s 20 million farmers: a combination of microbiological innovation, technical dissemination, financial support, and supply chain development will be necessary.

Academic research and feedback from local experience are needed to confirm the long-term effects on soil health, microbial biodiversity, and greenhouse gas balances. For complementary and climate-resilient farming practices, see also approaches toirrigation and water management recently developed techniques that optimize production in situations of water stress (Science and Future) and sustainable rice farming techniques explained by local specialists (DoinAsia).

Resources and further reading

To delve deeper into the technical and scientific aspects, one can consult a thesis dealing with related agronomic questions (HAL), summaries on the use of beneficial microorganisms in crop protection (Koppert) and visual examples of drone spraying available online (video).

Frequently Asked Questions: Microorganisms to protect rice paddies from burning