Alliance, MATI launch tropical field trials for enhanced rock weathering

The Alliance of Bioversity International and CIAT and MATI have signed a five-year agreement to test enhanced rock weathering in smallholder farms across tropical regions, starting with field trials that will measure crop yields, soil health and climate resilience. The work aims to generate independent evidence on whether crushed basalt can be scaled as a free, carbon-funded farming practice in places with degraded, acidic soils.

Why it matters: - Enhanced rock weathering could offer tropical smallholders a way to raise yields, improve soil health and strengthen resilience to heat and drought. - The practice also removes carbon dioxide from the atmosphere in stable mineral form, creating a climate benefit alongside the agronomic one. - If the results hold in farmers’ fields, the approach could be recommended beyond a single company’s reach.

What happened: - The Alliance of Bioversity International and CIAT, part of CGIAR, and MATI announced a global memorandum of understanding to run agronomic field trials of enhanced rock weathering in smallholder farming systems. - The five-year framework covers trial design, data sharing, publication and joint fundraising. - The announcement came at the Africa Food Systems Forum in Kigali, Rwanda, on Sept. 2, 2026.

The details: - The Alliance works across Africa, Asia and Latin America and the Caribbean on crops smallholders grow and the soils they grow them in. - MATI spreads finely ground basalt on smallholder fields at no cost to farmers, funded by carbon credit sales. - The practice, known as ERW, returns minerals stripped from soils by repeated harvests, raises soil pH and improves nutrient availability. - The same weathering process locks carbon dioxide away in stable mineral form for more than 10,000 years. - The revenue from carbon credits covers the rock, the spreading and the science, so farmers pay nothing and no subsidy is required. - The partnership will test ERW in tropical smallholder systems, where soils are often older, more acidic and more weathered than in temperate commercial farming. - Suitable basalt is widely distributed across the target regions. - MATI reported a median yield increase of about 25% across 235 paired plots in India. - The trials will be carried out in farmers’ own fields season after season. - The work will also examine whether crushed basalt can be recommended responsibly across diverse tropical crops and agroecological conditions. - Dr. Wanjiru Kamau-Rutenberg said the Alliance’s role is to generate independent, published evidence under real-world conditions. - Dr. Marcela Quintero said the agreement is intended to translate rigorous science into practical solutions at scale. - Shantanu Agarwal said early results in Zambia resemble results MATI saw in India. - Tom Mills said policy frameworks for enhanced rock weathering require independent, published agronomic data from tropical smallholder systems.

Between the lines: - The partnership is designed to move ERW from promising climate technology to evidence-backed agricultural guidance. - Independent replication matters because published results from tropical smallholder systems are still limited. - The focus on publication whether or not results are favorable suggests the Alliance wants the trials to be useful for ministries, extension services and farmer organizations, not just investors or carbon buyers. - The work also tests whether a carbon-financed farming input can scale in regions where degraded soils constrain yields for hundreds of millions of smallholders.

What's next: - The Alliance will lead trial design and analysis. - The partners will publish findings whether or not the trials favor ERW. - The studies will measure yield, fertilizer efficiency, soil water retention, crop response to heat and drought, and grain nutritional quality. - Results will help determine whether enhanced rock weathering can be recommended across tropical smallholder systems and inform future policy frameworks.

The bottom line: - The Alliance and MATI are betting that independent tropical field data will show crushed basalt can be both a climate tool and a practical farm input for smallholders.