Yanmar Advances Sustainable Agriculture with Rice Husk Biochar

Osaka, Japan (September 15, 2026) – Rice husks are one of agriculture's most abundant byproducts. Yanmar has developed a practical way to turn that material into value for farmers and the climate.
Yanmar Energy System Co., Ltd., a Yanmar Holdings group company, began taking orders in Japan in September 2026 for a system that converts rice husks into biochar. The system is intended for grain storage and rice-processing centers that must manage large volumes of husks.
By returning the resulting biochar to farmland, operators can improve soil while storing carbon in a stable form that resists decomposition. The approach connects waste management, soil health and decarbonization in a circular agricultural model.

A local challenge with global relevance

Japan's rice sector generates an estimated 2 million metric tons of rice husks each year, according to Yanmar's estimate in materials submitted under NEDO's Green Innovation Fund program. Disposal is a persistent challenge. Open burning is increasingly restricted or discouraged, while smoke, odors, fine particulate matter and the possible formation of carcinogenic crystalline silica under poorly controlled combustion conditions can create environmental and health concerns.
Rice-producing regions around the world face the same fundamental question: how can a low-value residue be managed without simply shifting the burden elsewhere? Biochar offers one
pathway by converting the husks into a material that can be used rather than discarded.

Designed for efficient, continuous operation

Yanmar commercialized the system after demonstration testing that began in 2023. Its proprietary high-temperature carbonization method is designed to suppress smoke, odors and the formation of crystalline silica while producing porous biochar with a larger surface area than lower-temperature rice husk charcoal.
The system uses an electric heater of approximately 3.2 kilowatts for about 1.5 hours to ignite the process. After ignition, heat from the rice husks sustains carbonization without fossil fuel or a secondary-combustion burner. Average power demand over 24 hours is approximately 1.5 kilowatts. Automation and remote monitoring support continuous operation, including overnight.

From biochar to healthier soils

The system has a rated rice husk input of 100 kilograms per hour and produces approximately 25 kilograms of biochar per hour on a zero-moisture basis. It can operate continuously for up to 100 hours.
The resulting porous biochar can adsorb fertilizer and other substances and may help improve water retention and drainage when applied to farmland. Because the carbon in biochar is resistant to decomposition, incorporating it into soil can also support long-term carbon storage and contribute to carbon-negative outcomes.

Building a path for a sustainable future

The rice husk biochar system is a Japan-focused product, but the problem it addresses is global. It demonstrates how Yanmar's experience in agriculture and energy systems can be applied to connect resource efficiency with practical outcomes for producers.
Rather than treating crop residues only as waste, the system creates a cycle in which a byproduct of food production returns to the land as a useful material. It is one example of how Yanmar is using technology to support more productive and sustainable relationships among energy, food and the environment.

System specifications

About Yanmar

diesel engine of a practical size in 1933. A pioneer in diesel engine technology, Yanmar is a global innovator in a wide range of industrial equipment, from small and large engines, agricultural machinery and facilities, construction equipment, energy systems, marine, to machine tools and components — Yanmar’s global business operations span seven domains. Guided by its Brand Statement, “A Sustainable Future – New Value Through Technology,” Yanmar provides advanced solutions to the challenges customers face on land, at sea, and in the city, working towards realizing a sustainable future.

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