Assessing the Impact of Mineral and Microbial Soil Amendments on Soil Carbon Sequestration and Crop Performance

Soil amendments are commonly used in agricultural soils to improve soil biogeochemistry and increase crop yield. Some soil amendments may also facilitate soil organic and inorganic carbon sequestration, though the full extent of carbon sequestration and its dependence on soil minerals and microbial associations remains uncertain. To determine the role of mineral and microbial amendments on soil biogeochemistry, crop performance, and carbon sequestration, we tested the effect of two soil amendments - a combined inoculum of bacteria (Bacillus) and fungi (Trichoderma), and a powdered basalt coated in a humic acid - on soil biogeochemistry (i.e., nutrient cycling, organic and inorganic carbon sequestration) and crop performance (i.e., nutrient use efficiency and yield) on a 1-acre corn plot at Cornells AgriTech campus in Geneva, NY. The basalt amendment was designed to rapidly dissolve in soils, adding alkalinity to facilitate inorganic carbon sequestration through enhanced weathering. The microbial inocula was designed to improve crop root development and nutrient use efficiency, increasing both overall crop yield and belowground organic carbon deposition. Corn rows were treated with either no amendment, the basalt amendment alone, or the basalt and microbial inoculum, and were monitored by regularly sampling soils, crop tissue, and soil pore water. Results will provide insight into the impact of combined soil amendments for carbon sequestration, the role of microbial processes in accelerating mineral weathering and belowground root development, and implications for agricultural sustainability and soil-based climate solutions.