Carbon-Negative Silicon Fertilizers

Mafix raised $5.4 million in pre-seed funding, led by Azolla Ventures, to commercially demonstrate its carbon-negative fertilizer, which converts abundant silicate rock into minerals that weather within a single growing season rather than the decades typical of conventional enhanced rock weathering. The Stanford-developed process releases nutrients into the soil to boost crop yields while permanently removing CO₂ as stable bicarbonate.

The funding will support the production of 1,000 tons of fertilizer, with Mafix strategically partnering with cement producers to utilize roughly 30% of idle global kiln capacity rather than building expensive new facilities.

As enhanced rock weathering seeks to overcome slow payoff timelines that have historically discouraged landowner participation, Mafix's rapid-weathering technology signals that pairing genuine agronomic benefits with faster carbon removal could make climate-focused fertilizers commercially viable at scale.