While nitrogen, phosphorus, and potassium remain the primary nutrients of concern for farmers, silicon is becoming an increasingly important crop input, with Stanford University spin-out Mafix aiming to produce it economically at scale.
The Seattle-based agtech start-up developed a mineral conversion process that enhances silicate rock weathering, Jade Marcus, CEO and cofounder of Mafix, told AgNavigator. Mafix uses cement kilns to make inert silicate rocks weather over time — as fast as a growing season — allowing nutrients to be released into the soil.
In addition to improving soil and crop health, silicon fertilizers can remove CO2 by converting the greenhouse gas into stable bicarbonate, Marcus said.
On Aug. 20, the start-up announced that it closed a $5.4 million pre-seed round, led by Azolla Ventures and supported by Astera Institute, Counteract VC, Impact Science Ventures, Plug and Play Ventures, and a Dutch family office.
Mafix will use the funding to scale up the technology and produce at least 1,000 tons of its silicon fertilizer, which will help the start-up move from small plot to larger field trials, Marcus said.
The start-up plans to tap into nearly 30% of global cement kiln capacity that is idle, allowing Mafix to minimize expensive scale-up costs compared to other processes and to produce a product that is affordable for farmers, she added.
The start-up is exploring a range of go-to-market strategies, including releasing standalone pH-modulation products, carbon products, or blends with traditional fertilizers to improve nutrient use efficiency.
“We are fertilizer first, but we also can remove carbon dioxide from the atmosphere, which is very different than a lot of the agronomic products that are put on fields today,” Marcus elaborated.
Silicon becomes an essential crop nutrient
Farmer interest and demand for silicon is on the rise as research highlights the importance of the crop nutrient. Earlier this year, the Association of American Plant Food Control Officials classified silicon as an essential crop nutrient, having previously been recognized as a beneficial nutrient.
While it’s the second most abundant element in the Earth’s crust, silicon is not plant available, meaning farmers can gradually deplete plant-available silicon from the soil over time, she added.
“When you’re able to apply plant-available silicon, there are very specific transporter genes. So, in rice, there’s Lsi1, Lsi2, and Lsi6, and these actually direct the plant-available silicon from the roots all the way to the shoots, where it polymerizes, precipitates out, and increases the structural integrity of the crop, so it’s better able to do photosynthesis. It stands straighter, so you don’t have to worry about lodging,” Marcus elaborated.