Coal-Based Humic Acid Fertilizer Effects on Soil Properties and Mustard Growth

Humic acid is an essential organic substance that improves soil quality and enhances plant growth. This study investigates the novel application of low-rank coal waste as a source of humic acid for agricultural purposes. Humic acid was extracted from coal and applied as a soil amendment to two contrasting soil types under greenhouse conditions. The application of coal-derived humic acid significantly improved soil pH, electrical conductivity, and organic carbon content, leading to enhanced mustard crop performance. Higher concentrations of humic acid promoted stronger plant growth and increased leaf greenness. The results highlight the potential of converting low-rank coal waste into humic-based fertilizers as an effective strategy for improving soil fertility and supporting sustainable agricultural practices.