Using Microbial-Induced Calcite Precipitation (MICP) to Improve Erosion Resistance and Revegetation in Soils after Wildfire Exposure

Climate change is causing more frequent and higher intensity wildfires. Wildfires alter soils’ physical properties leading to wide range of devastating impacts on agriculture, infrastructure, and the environment. Microbial Induced Calcite Precipitation (MICP) technique employs microorganisms to precipitate calcium carbonate which binds soil particles together. MICP was found to be sustainable treatment method for enhancing soil stability and reducing erodibility, however, there is limited validation of this technique on wildfire- affected soils. In this research study, soil samples were burned to simulate wildfire conditions. MICP was used to treat burned soil samples by stimulating native microbial communities that survived burning. Treated samples were tested for their shear strength, erosion resistance and ability to support revegetation after one- and two- week of treatment durations. Soil burning, as expected, resulted in depletion of organic matter, increase in fines content and erodibility and reduction in shear strength. Revegetation growth experiments in burned soil samples were impaired. MICP-treated samples showed improvements in shear soil properties, where the internal friction angle was restored to the natural value of 36°. After one- week MICP treatment, erosion rates decreased to values comparable to those of natural soils. For the two- week MICP treatment and under the experiment conditions, soil erosion rate was minimal and below measurable limits. Both one- and two-week treated samples showed a visually improved revegetation growth. The results demonstrate the novel use of stimulating native microbial communities in lieu of using imported bacteria. And, showed promising short-term solutions of stabilizing post- wildfire soils and promoting vegetation root systems which could further stabilize the soil in the long term.