This is Biochar: Sustainable Rice Cultivation in Salt-affected Soil

Dr. Bualuang Faiyue has been studying soil salinity in Thailand for years. In 2019, he discovered biochar and has focused his salinization research on its solution potential ever since.

Soil salinity is the amount of salt in the soil — and when the salt level increases beyond balanced levels, it’s called salinization. While salts naturally exist in both soil and water, and salinization can happen due to natural processes, climate change and rising sea levels is exacerbating the process. Amongst its harmful effects are soil degradation, water contamination, and crop failure. 

Dr. Bualuang Faiyue, a dedicated researcher at Chulalongkorn University’s Environmental Research Institute in Thailand, is trailblazing the use of biochar to address soil salinity in rice fields. Upon joining the University, he discovered his colleagues were already exploring the potential of biochar to mitigate a number of threats to soil health, from fertility to toxicity and PFAs contamination. 

Inspired by their work and driven by his passion for agricultural sustainability, Dr.Faiyue embarked on a mission to apply biochar’s transformative properties to mitigate soil salinity’s impact on rice cultivation.

In 2024, he attended 2024 IBI’s Biochar Academy in Thailand to catapult his biochar research and projects to the next level.

“Biochar is a strategy that we can use to mitigate climate change.”

– Dr. Bualuang Faiyue

The Problem of Soil Salinity

Soil salinity poses a significant threat to agricultural productivity, biodiversity, and economic revenue, with 833 million hectares of salt-affected lands estimated worldwide. Finding effective solutions for soil salinity is critical, particularly in the rice fields of Thailand as the country is one of the world’s largest rice exporters (around 8 million metric tons annually). 

In Thailand, the salinity of the soil is rooted in its geological origins. The presence of salt-bearing rock formations and the movement of saline groundwater to the surface is a prime foundation for high salinity soils, especially in the northeastern region of the country. Yet, this problem isn’t only an issue for arable soils inland; as climate change causes sea level rise, seawater intrusion on the coasts exacerbate the problem.  

Alongside natural occurrence, an accumulation of salts in the soil can be caused by inefficient water management and the use of salt-rich water for irrigation. Salt stress can lead to poor plant growth, reduced crop quality, and in severe cases, crop failure. Salinity can render fields inhospitable, leading to decreased yield, food stress, and economic losses for farmers — not to mention the loss of a culturally significant crop that is a staple of the Thai diet.

Biochar: Soil Amendment + Sustainable Solution

Dr. Faiyue’s research focuses on how biochar can improve soil structure, nutrient retention, and water holding capacity — crucial factors for combating soil salinity. By incorporating biochar into saline soils at various ratios, he aims to enhance rice plant survival and productivity.

Biochar has proven itself as an asset for farmers across diverse landscapes and geographies due to its profound impact on soil health and soil structure. Amidst its myriad of benefits, the carbon-rich material helps mitigate soil salinization through several mechanisms: 

• Improves Soil Structure: Biochar enhances soil structure by increasing porosity, which improves water infiltration and retention. This helps flush salts out of the root zone more effectively, reducing salinity levels.
• Increases Cation Exchange Capacity (CEC): Biochar has a high CEC, which means it can hold onto essential nutrients and release them slowly. This property helps bind and immobilize salts, preventing them from negatively impacting plant roots.
• pH Buffering: Biochar can help buffer soil pH levels. Saline soils are often alkaline, and biochar can help neutralize this alkalinity, creating a more favorable environment for plant growth.
• Enhances Water Holding Capacity: Biochar increases the soil’s ability to retain water, which is crucial in saline conditions. Better water retention helps dilute salts in the soil, reducing their concentration around plant roots.

Dr. Faiyue’s experiments, occurring over one crop cycle of rice (about three to four months), applies biochar produced from rice husks directly back onto the feedstock’s original field. Producing and applying the biochar directly at the source site keeps the experiment process sustainable by reducing transportation emissions and costs, while providing an opportunity for deeper relationships with participating farmers. 

Collaboration forms a cornerstone of Dr. Faiyue’s work. He collaborates closely with local farmers, engaging them in biochar production and application processes. After his participation in the 2024 Biochar Academy, he took his learnings about artisanal kilns and made one himself with the help of his research team. He has since taught farmers how to make the kiln and produce biochar with it as well. 

“I ask for help or cooperation from farmers,” says Dr. Faiyue. “And then we produce biochar together. And they apply it. We work together; like they’re a research assistant.”

The impact of the research, in effect, expands beyond just the visiting teams from Chulalongkorn University. When researchers like Dr. Faiyue share the knowledge of biochar’s positive impact on rice cultivation, the knowledge remains in the community once that experiment is finished and they return to Bangkok. Communities and farmers can continue to produce biochar, apply it, and teach what they now know to others.

This participatory approach not only empowers farmers with new agricultural techniques but also ensures that research findings translate effectively into practical solutions on the ground.

Beyond the beneficial community empowerment, the experiment is seeing promising results: rice plants treated with biochar exhibit high survival rates and increased productivity compared to untreated controls. This research not only highlights biochar’s potential to mitigate soil salinity but also underscores its role in sustainable agriculture and climate change mitigation.

Challenges and future directions

In tandem with the promising results, Dr. Faiyue faces challenges such as the variability of soil salinity levels across different fields and the need for sustained funding to expand his research.

Salinity level is not uniform — not across Thailand, and not even across one experiment site. The ratio or grade of biochar needs to adapt to the salinity they’re faced with, which ultimately creates a challenge for instructing farmers how to apply the biochar on their own. What might have worked for one farmer’s soil may not work for another’s. 

Beyond the first year of biochar application, the next challenge is usually funding the research. Scholarship or funding is often provided in one-year terms. 

“It’s the pain of a researcher,” says Dr. Faiyue. “But again, this is an opportunity. So, I have to apply for more funding to continue my work.”

Looking ahead, he envisions a future where biochar becomes a widely adopted tool in global agriculture, supported by collaborative efforts among researchers, farmers, and biochar producers. The ecosystem of biochar in Thailand is nascent, and encouraging a practice of knowledge-sharing among biochar producers could be game-changing for the industry, and for sustainable agriculture. His vision includes establishing connections between academia, industry, and farming communities to ensure biochar’s widespread adoption and impact.

Driven by his deep-rooted belief in the transformative power of biochar, Dr. Faiyue sees his work as not just a career but a mission to make a positive impact on society. 

“I think passion is important. I think this is the most important thing,” Dr. Faiyue says. “My work is beneficial for people, not only in Thailand. It makes me happy and proud.” 

He is not only addressing pressing agricultural challenges but also contributing to broader efforts to combat climate change and promote sustainable development. As he continues to expand biochar research on soil salinity, Dr. Faiyue remains committed to realizing a future in which agriculture thrives in harmony with the environment.

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