Coal mining leaves behind coal gangue, an industrial waste that depletes soil nutrients, affecting plant growth and ecosystem recovery. A recent study published in Scientific Reports by Qiuyun et al., examines how biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More (BC) and polyacrylamide (PAM) improve coal gangue soil (CGS) by enhancing its physicochemical properties and enzyme activity. Their findings suggest that a combination of 2% BC and 0.05% PAM could be a cost-effective strategy for improving soil in mining-affected areas.

The research involved a controlled incubation experiment testing different BC (1%, 2%, 5%) and PAM (0.02%, 0.05%, 0.1%) combinations against a control group without amendments. The results showed that higher BC and PAM levels significantly increased soil organic carbon, enzyme activity, and water retention. Specifically, the B5P10 treatment (5% BC and 0.1% PAM) had the highest organic carbon content, increasing by nearly 58% compared to untreated CGS. Additionally, key soil enzymes like α-glucosidase and N-acetyl-glucosidase, essential for nutrient cycling, were significantly more active in treated soils.

Biochar, derived from organic material, is known for its ability to retain water and improve soil structure. As a synthetic polymer, PAM binds soil particles, preventing erosion while also increasing water-holding capacity. The combination of BC and PAM enhances soil stability, making CGS more suitable for plant growth and reducing environmental risks from mining waste. While BC and PAM significantly enhanced enzyme activity, excessive additions did not necessarily yield greater benefits, emphasizing the importance of optimized application rates.

These findings provide a promising solution for rehabilitating degraded mining soils. By using BC and PAM in targeted amounts, land managers can improve soil fertility, water retention, and microbial activity, supporting vegetation growth in reclaimed areas. This research not only advances soil restoration techniques but also offers a sustainable approach to managing coal mining waste.

SOURCE: Fan, Q., Li, N., Geng, Y., Dong, Y., & Zhang, C. (2025). Variation in soil enzyme activity with amendments of biochar and polyacrylamide in coal gangue soils. Scientific Reports, 15, 4596.