While crop plants do sequester some atmospheric carbon dioxide (CO2) via photosynthesis, they could always use a bit of help. California-based startup Andes is aiming to provide that help, by putting carbon-capturing microbes in the soil of farmers' fields.
Here's the basic idea behind how the Andes system is claimed to work …
At the start of each growing season, the farmer adds both the regular crop seeds and the special microbes to the soil. "The microorganisms we are using are proprietary, but we can share they are naturally-occurring, beneficial soil microorganisms and were isolated from soil samples in the continental US, where traditional agriculture is practiced," Andes CEO/co-founder Gonzalo Fuenzalida told us.
Once the seeds sprout and the plants start growing, the microbes establish themselves in the roots, growing along with them. As the plants proceed to sequester CO2 and use it to build up their own biomass (as they would anyways), the microbes also sequester CO2 – which they receive both from the atmosphere and via the roots – converting it into minerals such as calcium carbonate and magnesium carbonate.
Those minerals remain in the soil, where they help the plants by boosting aeration, water permeability and the availability of soil nutrients. Rainfall gradually moves the minerals deeper into the ground, so they don't accumulate to problematic levels in the topsoil.
Importantly, the sequestered CO2 stays captured in the minerals indefinitely. By contrast, when crop plants are left to decompose in the fields (or are burned) after being harvested, they release much of the CO2 that they previously captured.
Also importantly, farmers don't have to pay for the service – in fact, they're paid to use it. Andes makes its money by selling carbon credits to corporate clients, with some of the revenue going to US$10-per-acre payments made to participating farmers. The service is currently available to US-based farmers whose fields have a topsoil pH greater than 6.0.
We're told that the Andes system has already been trialled on farms in North Dakota, Minnesota and Wisconsin, where it was found to sequester CO2 at an average rate of 1 to 3 tonnes (1.1 to 3.3 US tons) per acre (0.4 hectares) per season.
"The durability of the minerals and the rapid CO2 sequestration rate puts Andes technology in a unique position, and differentiates it from soil organic carbon buildup approaches that are currently implemented in agricultural fields," said Fuenzalida.
Source: Andes
