Coal char and algae soil amendment for enhanced soil productivity and carbon capture

Overview

This solution combines pyrolyzed coal residues (coal char) with terrestrial algae sourced from biotic soil crusts to create an innovative soil amendment. Coal char serves as an economical alternative to biochar, while algae acts as a biogenic fertilizer. Together, they dramatically increase the organic carbon content, water retention, and ion exchange capacity of soils. The combination represents a cost-effective, carbon-neutral approach to soil improvement, with the added benefit of providing a high-volume alternative market for coal beyond thermal electricity generation. Algae also serves as a high-volume capture agent of CO2, further enhancing the environmental value of the amendment.

Technical specifications

• Coal char as organic carbon source: Pyrolyzed coal residues provide a stable, economical organic carbon source that improves soil structure and chemistry.
• Terrestrial algae as biogenic fertilizer: Algae sourced from biotic soil crusts contribute nutrients and biological activity to amended soils.
• Improved soil properties: Increased organic carbon content, enhanced water retention, and greater ion exchange capacity compared to untreated marginal soils.
• Algae survival and proliferation: Desiccated algae applied to soils have been shown to survive and proliferate, supporting long-term soil biological activity.
• Application versatility: Suitable for use with rangeland grasses and potentially other crops in marginal soil environments.

Technology readiness level

The technology has progressed through laboratory, greenhouse, and field validation. Laboratory tests have confirmed increased water retention and ion exchange in coal char-amended soils. Greenhouse and field trials have demonstrated increased and accelerating biomass accumulation over two growing seasons using rangeland grasses as a model. Current and future validation efforts include more extensive field trials incorporating algae, monitoring of physical, chemical, and biotic soil properties, and longitudinal analysis of algae fate in the soil column. Complementary laboratory and greenhouse experiments will further characterize amended soil composition and properties.