Iron slag might help keep carbon in the ground

A nice photo package (see it here) from Dartmouth College about a test to increase carbon capture in soils:

Most carbon in soil is eaten by microbes and respired back into the atmosphere as carbon dioxide, contributing to global warming. As part of her culminating experience project, Molly Stevens ’25 has spent her senior year working with Professor of Earth Sciences Carl Renshaw and Senior Research Scientist Josh Landis on a possible solution. 

By adding a mixture of iron and silica, aka iron slag, to the soil, Stevens hopes to trap carbon in a form that’s resistant to degradation by the microbes, keeping it in the ground. In a project funded by the Climate Futures Initiative, Stevens, Renshaw, and Landis on March 11 added the slag to two experimental plots at the Organic Farm.

If the test is successful, farmers could be incentivized to add iron slag—currently an industrial waste product—to their fields to improve their yields while also possibly earning carbon capture credits.