Washington Farm Fights Climate Change with Rock Dust

It may not seem like it, but climate change has sparked some positives. It inspires collaboration, creativity and innovative solutions to take on a challenge that is bigger than all of us. It brings people together who want to do their part to help the Earth and everything on it.

One Organic Valley farm family, a university and a forward-thinking company are among these creative collaborators.

Jack and Maynard Mallonee are participating in a project led by carbon removal project developer Basic Dust and the University of Copenhagen, to try a climate solution called enhanced rock weathering on their organic dairy farm in Washington. 

Simply put, farmers spread crushed rock dust on fields to capture carbon and improve soil health. A little dust goes a long way! Not only can enhanced rock weathering help the climate, but it may also improve soil, forage quality and crop yields.

Carbon Removal: A Key Solution for Climate Change

Climate solutions should address two components of climate change: preventing more greenhouse gas emissions from entering the atmosphere and removing excess carbon dioxide already in the atmosphere. 

“Climate change is a waste management problem,” said Mike Robinson, Basic Dust CEO. “The real problem isn’t just this year’s emissions. This year’s emissions are just adding to the pile of waste that we’ve pumped into the environment. How do we start cleaning up the mess we’ve made?”

One possible answer is carbon removal. Carbon removal is the process of taking CO₂ out of the atmosphere and putting it into the geosphere — the solid parts of the Earth, like rocks and soil.

There are several carbon removal techniques and technologies, and more are being invented around the world. Planting a forest is one example of natural organic carbon sequestration, as trees put CO₂ into the soil. Direct air capture is another that uses fans the size of shipping containers equipped with filters that will grab onto CO₂ as the air moves through them. That CO₂ is then turned into steam that is eventually pumped underground. 

Then there’s enhanced rock weathering — a newer nature-based option with exciting potential! 

Enhanced Rock Weathering: What It Is and Why It Matters

Earth already has its own built-in carbon removal method called weathering. When rain falls, it absorbs CO₂ from the earth, forming a weak acid called carbonic acid. When the acid hits certain rocks, such as volcanic basalt, it reacts with minerals to form a natural bicarbonate, locking up that CO₂. This eventually flows into the ocean.

Enhanced rock weathering speeds up that process by taking those rocks, grinding them into a fine dust and placing the dust where it can react with water that contains CO₂.

“All of those billions of little particles of dust have lots of surface area to react with the alkaline minerals and form bicarbonate,” Robinson said. 

Of all the carbon removal processes, enhanced rock weathering is low-cost and highly scalable, as it can take place wherever there’s water with carbonic acid, such as open fields that get a lot of rain or even natural bodies of water that have high acidity. The one downside is if there is no liquid water — because of a drought or deep freeze — then carbon can’t be removed. But as long as rock dust is still present in the soil, once it rains again or the ground thaws, carbon removal will resume.

Where Does the Rock Come From?

Most rocks used for enhanced rock weathering come from volcanic quarries. The dust used in the project at the Mallonee farm came from olivine rock, sourced from a mine in Oregon. Olivine is ground to create olivine sand used for industrial purposes like foundry casting. During the process, some sand is ground too fine and would otherwise become waste. Basic Dust recycles the dust to use for enhanced rock weathering on the farm. It’s recycling and carbon removal all at once!

Does Acquiring the Rock Emit CO₂?

CO₂ is emitted in acquiring the rock for enhanced rock weathering, but Robinson said the amount is carefully tracked and incorporated into the carbon removal equation. 

“You figure out what your gross removal is, then you deduct all the emissions that went into everything you did,” he said.

Because the olivine dust used on the Mallonee farm was already a byproduct of sand production, no additional carbon was emitted to collect it.

3 Reasons Rock Dust Benefits Farmland — Especially Organic Operations

Farm fields make an ideal location for enhanced rock weathering, not only because they can easily capture rainwater, but also because the rock dust offers benefits to the soil.

1. It corrects soil acidity.

Most farmers spread pulverized limestone or dolomite to raise their soil pH, a process called liming that has been recognized since Roman times. Maynard said they’re always adding more natural lime to their fields, so this benefit was one of the main draws for participating in the project. At roughly half the cost of regular lime, it offers significant savings.

Also, Organic Valley’s CROPP Carbon Insetting Program incentivizes and assists Organic Valley farmers in implementing regenerative, climate-smart farming practices. 

“If we can get the effects of liming, but also get some carbon credits, it could be very beneficial to farmers,” Maynard said.

Spreading it was the same as lime, too — in fact, the team used a traditional lime spreader to apply the rock dust on his fields.

Maynard spread 3 tons of the olivine rock dust in September 2025. He hasn’t soil tested his fields to see if it’s changed the soil pH yet, but research shows that it works. One four-year enhanced rock weathering study conducted at the University of Illinois Energy Farm near Urbana, Illinois, found that applying about 20 tons per acre of olivine dust every fall significantly increased soil pH on corn and soybean fields.

2. It enhances soil fertility. 

Depending on the type of rock used, the dust can contain important minerals like magnesium, calcium, potassium and silicate. The olivine dust used in this project was rich in magnesium and silicon dioxide. 

Higher soil magnesium levels can grow forage with higher magnesium content, which can help prevent grass tetany, a serious cattle disease. Some of his soil is higher in calcium, which magnesium balances.

Robinson said the amount of dust to apply depends on the composition of the rock. For a rock that has a lower composition of calcium oxide and magnesium oxide, such as olivine, you must apply a larger amount, as those two alkaline minerals cause the reaction to form bicarbonate.

The combination of improved soil pH and fertility may even lead to higher yields as shown in the University of Illinois study. Corn and soybean yields saw statistically significant improvements.

3. It’s safe for organic farming.

The National Organic Program sets strict rules for which soil amendments organic farmers can use. Organic farmers cannot use synthetic fertilizers that many conventional farmers rely on. Maynard was able to get the rock dust verified as an organic product, which will give him and other organic farmers another option for improving their soils. For soils lacking magnesium, this could be a “very useful tool,” he said.

Because the dust won’t move anywhere but into the soil, it’s safe for the water, the air and his cows. A University of California Davis–Cornell field study on enhanced rock weathering showed the material stays in the soil layer where it’s spread, which is how it removes carbon.

We must also acknowledge animal waste, which is highly beneficial to soil. While rock dust has advantages, the Mallonees would never give up cow manure as a natural soil additive. 

All cows on Organic Valley farms are pasture-raised, which not only benefits the soil, but has been shown to reduce greenhouse gas emissions by an average 24% compared to conventional dairy farms. In fact, grazing land stores up to 10 to 30% of the world’s soil carbon reserves.

Capturing How Much Carbon-Enhanced Rock Weathering Removes

Carbon dioxide removal rates from enhanced rock weathering can vary due to the rock used, the amount of rock dust applied, the amount of carbonic acidic water that interacts with it, and even the crop system it’s used in.

On the Mallonee farm, they’re testing enhanced rock weathering on two cropping systems: an annual crop of triticale, peas, vetch and ryegrass where Maynard tilled the rock dust in, as well as a no-tilled field that’s in a permanent hay crop. 

The field is split into two sections: one for testing and one for comparison. Each section has 10 zones, and in every zone, two types of sensors are buried in the soil to monitor activity. One tracks how much carbon is leaving the soil, while the other measures key nutrients as water moves through. Together, they help scientists understand how rock dust is working beneath the surface.

Since both types of sensors must be buried, Basic Dust will use traditional soil and water samples from the permanent hay crop to measure carbon removal, ensuring the crop and soil remain undisturbed.

They can pull the data off the other sensors by walking the fields with a handheld collector to capture real-time results. Basic Dust has collected data from these sensors twice since applying the dust in September, and they are already seeing changes in CO₂ removal. Data from the other sensors will be available later in 2026.

After a year, they will have applied about a ton of rock dust for every 2.5 acres of land.

“That’s a ton of CO₂ that’s been pulled out of the atmosphere and put back into long-term storage in the geosphere by being converted to bicarbonate,” Robinson said.

If a ton of CO₂ can be pulled out of the atmosphere from a few acres of the Mallonee farm, imagine the impact if this organic farming practice was applied to millions of acres! 

“We can be pulling millions and millions of tons of CO₂ out of the environment,” Robinson said. “That’s how we start to put a dent in that 2 trillion-ton legacy pollution cloud we’ve pumped into the environment.”

Pursuing Carbon Neutrality While Supporting Organic Farming

Exploring enhanced rock weathering is evidence of Organic Valley’s commitment to organic farming and protecting its future.

The project received $50,000 in support from an Organic Valley Farmers Advocating for Organic grant. The grant program is funded entirely by voluntary contributions from Organic Valley farmers and is the largest farmer-funded grant program in the U.S. This project will help guide enhanced rock weathering for organic farmland, so other farmers can improve their soils while also helping the environment.

Enhanced rock weathering can also help Organic Valley in its pursuit of becoming carbon neutral by 2050. Enhanced rock weathering is a carbon insetting process which reduces carbon emissions within our own supply chain.

“We are doing this for the right reasons — to fix the climate,” Maynard said. "We have to actively clean up the environment and let nature do its job.”

Organic Valley farmers are committed to doing what’s right for their land, their cows and the environment. Enhanced rock weathering benefits all three.