Effect of Treatment Solution Chemistry and Soil Engineering Properties due to Microbially Induced Carbonate Precipitation Treatments on Vegetation Health and Growth

Microbially induced carbonate precipitation (MICP) is a soil stabilization technique that relies on natural biological processes to improve engineering properties of soil. This biological soil improvement method has gained popularity over the last decade. However, the unanticipated consequences of this method on vegetation and the environment are still unclear. This study presents the first attempt to strategically investigate the interaction between the MICP-treatment technique and vegetation health and growth. Bermuda grass was treated with different concentrations of MICP solution constituents and byproducts to identify the chemical(s) responsible for changes in plant health (e.g., dry blades) and to establish an appropriate concentration range. In addition, phosphorus was added to the treatment solution to mitigate the dryness of MICP-treated plants. Visual MINTEQ analyses were used to determine the optimum phosphorus concentration to still encourage sufficient calcite precipitation. Elemental analyses were used to confirm the compatibility of the added phosphorus concentrations with MICP. Post-treatment effect of MICP on seed growth was investigated by planting seeds in soils treated to varying cementation levels. Up to a certain improvement level, cementation formation did not affect seed germination and growth. However, higher levels of cementation hindered root growth and vegetation coverage. The findings of this study provide implications and directions regarding vegetation growth and establishment for future field implementation of MICP.