Hemp + Biochar: New Study Explores Big Benefits For Soil and Climate

Researchers at Washington State University (WSU) have launched a six-year, $5 million study to test what happens when farmers combine industrial hemp cultivation with biochar soil additives​. The project, funded by the U.S. Department of Energy, will examine the long-term impacts on soil health, crop yields and even greenhouse gas emissions from farming​. Scientists suspect this hemp+biochar pairing could amplify the benefits each offers on its own – potentially supercharging soil fertility and locking away more carbon in the ground​.

What Is Biochar?

Biochar is a charcoal-like substance created by heating organic matter in a low-oxygen environment (a process called pyrolysis)​ Instead of burning to ash, the biomass (such as wood, crop residues or manure) carbonises into a stable form of carbon-rich charcoal. When added to soil, biochar can improve soil structure, boost fertility, and sequester carbon that would otherwise return to the atmosphere​.

In essence, it’s a way to turn plant waste into a long-lasting soil enhancer that also traps carbon for the long term.

Hemp’s Natural Soil Benefits

Industrial hemp, often grown as a rotational crop, is prized for its ability to rejuvenate and rehabilitate soil. Hemp’s deep root system breaks up and aerates compacted ground, helping to repair soil structure and add nutrients for the next crop​. Those long roots also draw water from deeper layers, improving drought resistance and even assisting in the removal of certain soil contaminants through a process known as phytoremediation​.

Farmers have found that planting hemp between other crops (such as wheat or corn) can restore organic matter to the soil and reduce the need for synthetic inputs. In short, hemp is widely regarded as a soil-friendly crop that boosts land health while it grows.

Hemp grows rapidly and develops long roots. In crop rotations, it helps improve soil by adding organic matter, breaking up hard ground, and even drawing out pollutants, all while absorbing carbon dioxide from the air.

Long-Term Study to Test a Powerful Combo

WSU’s new research initiative aims to find out if combining these two tools – hemp and biochar – yields compounded benefits for agriculture and the climate. The study brings together university scientists, a tech start-up, and working farmers in Washington State. Participating growers (including members of local Indigenous communities) will apply biochar to their fields and rotate hemp with traditional crops like wheat, corn and chickpeas​.

Researchers from WSU, Pacific Northwest National Laboratory and the University of Connecticut will monitor how this affects crop growth, overall soil ecology, and even soil emissions over time​. They plan to test two different hemp rotation schedules and more than a dozen different biochar treatments to see which combinations work best​.

To measure results, the team is using high-tech tools. Cambridge-based company Yard Stick PBC is contributing advanced soil probes that use spectroscopy for real-time carbon analysis in the field​. “Biochar’s role in the rapid, durable decarbonization of agricultural supply chains is very promising,” said Yard Stick CEO Chris Tolles, whose company’s mission is to “activate soils for climate and agricultural impact.”

By directly measuring soil carbon and health indicators, the researchers hope to quantify how much extra carbon is being stored and how soil fertility changes with the hemp+biochar approach.

Expected Benefits: Better Soil, Lower Emissions

Project leaders anticipate that this combined strategy could lead to healthier soils and reduced climate impact if it performs as hoped. “Together, they might amplify each other’s effects,” noted Dr. David Gang, the WSU biochemist heading the study​. Below are some of the key potential benefits highlighted by the research team:

• Richer Soil, Less Fertilizer: Biochar and hemp both add substantial organic carbon to the soil, improving fertility so that farmers can use less chemical fertilizer over time​. Hemp draws up nutrients and leaves behind organic matter, while biochar helps keep those nutrients in the root zone. According to Gang, this means growers might “use less fertilizer,” which could save them money and effort​.
• Carbon Storage & Lower Emissions: When biomass is turned into biochar, most of its carbon is locked into a stable solid form instead of releasing as CO₂​. That carbon can remain in the soil for decades, effectively pulling greenhouse gases out of the atmosphere. If farmers need less fertilizer thanks to healthier soil, that also cuts emissions (since manufacturing and applying fertilizers is energy-intensive and produces greenhouse gases)​.
• Improved Water Retention: Biochar’s porous structure can hold water like a sponge, helping soil stay moist longer​. At the same time, hemp’s roots improve soil porosity and reach deep moisture. The combination could make fields more resilient to drought by increasing the soil’s water-holding capacity​.
• Energy & Cost Savings: Building soil health naturally can translate to fewer tractor passes, less irrigation, and lower input costs. Gang expects the hemp+biochar treatments to yield “significant energy and labor savings, while decreasing environmental impact” for farmers​. In other words, what’s good for the soil could also be good for a farmer’s bottom line by trimming fuel, water, and chemical bills.

While results will be gathered over several growing seasons, the hope is that this eco-friendly formula can boost crop productivity and soil vitality in a financially sustainable way​. If successful, it may encourage broader adoption of biochar use and hemp rotations in mainstream farming as a climate-smart practice.

From Hemp Waste to Biochar Treasure

Interestingly, hemp itself can be the feedstock for making biochar. Typically, farmers harvest hemp for its seeds, flowers, or fiber and are left with stalks and husks that have little value. Rather than burning or tossing out this biomass, it can be turned into biochar through pyrolysis. Hemp stalk biochar is already drawing attention as a sustainable, value-added product: one recent study found that hemp biochar produced at very high temperatures has unusual electrical conductivity properties, hinting at possible uses in electronics or energy storage​.

For most growers, however, the chief appeal of hemp biochar would be agricultural. Converting hemp leftovers into biochar ensures every part of the crop is used – a win for waste reduction​. Farmers could take what was once a disposal problem and transform it into a soil booster (or even a new revenue stream by selling biochar). The process also locks in the carbon that the hemp plant absorbed from the air during growth, storing it in the charcoal instead of letting it escape as CO₂. “Initially, there was no use for hemp stalk after harvesting the ‘useful’ parts. However, creating biochar ensures that all parts of the hemp plant are used,” notes one industry report​. In short, turning hemp into biochar closes an important loop: it creates a useful product from agricultural waste and furthers the climate benefits by keeping carbon out of the atmosphere.

Hemp stalks can be transformed into biochar via pyrolysis, as shown above. The process converts leftover biomass into a carbon-rich soil enhancer. Researchers say this not only improves soil fertility but also stores carbon in a stable form, helping to fight climate change.

Sustainable Practices at Margaret River Hemp Co

The ethos behind the WSU study – making agriculture more sustainable by using hemp and its by-products – resonates strongly at Margaret River Hemp Co. Sustainability and full utilisation of the hemp plant have been cornerstones of the company’s operations. In fact, co-founders Georgina Wilkinson and Gary Rogers were recently recognized for launching Western Australia’s first hemp processing facility, Margaret River Hemp Processing, which now allows locally grown hemp to be turned into useful raw materials on home soil​.

This facility separates the hemp stalk into fiber (used for textiles and insulation) and hurd (the woody core, used in hempcrete building materials, animal bedding, and more). By processing hemp in-state, the company ensures farmers have a market for the whole crop – greatly reducing waste and the need to ship bulk material long distances.

Not content to stop at fibers and building products, Margaret River Hemp Co has also been experimenting with biochar on a small scale. The company currently makes small batches of hemp biochar from locally grown hemp stalks in Margaret River​.

Instead of sending leftover stalks to the burn pile, they convert them into an “organic activated charcoal” ingredient for a unique line of Australian-made body care products​. (For example, the company’s hemp charcoal soaps and scrubs use this biochar for its skin-cleansing properties.) It’s a messy, hands-on process that the team has to schedule carefully around Western Australia’s fire season, but they are passionate about finding innovative uses for every part of the hemp plant. “Creating biochar ensures that all parts of the hemp plant are used,” the company notes – turning farming by-product into value-added products while keeping carbon out of the air​.

These home-grown sustainability efforts mirror many of the ambitions of the WSU research. By developing hempcrete building materials, hemp-based textiles, and hemp biochar products, Margaret River Hemp Co is showcasing how a circular economy in hemp can work: the plant is grown, processed, and returned to the economy (or the earth) in beneficial ways at every step. Carbon absorbed by the fast-growing hemp is either built into long-lasting construction materials (in the case of hempcrete and fiber) or sequestered in soils and products (in the case of biochar and hemp charcoal goods). It’s an approach that not only minimizes waste but also maximizes the environmental upsides of hemp. As more research – like the WSU project – sheds light on hemp’s agronomic and climate benefits, companies such as Margaret River Hemp Co are well positioned to put those findings into practice.