Biochar and Beneficial Fungi Collaborate to Rehabilitate Soils Degraded by Coal Mining

In the quest to rejuvenate landscapes scarred by the coal mining industry, a groundbreaking three-year field experiment has unveiled a promising synergy between biochar and arbuscular mycorrhizal fungi (AMF). This research, emerging from the reclaimed mining soils of Shanxi Province in China, elucidates how the co-application of these two nature-derived inputs can dramatically enhance soil health, nutrient availability, microbial diversity, and ultimately, crop yield. The study, meticulously documented in the journal Biochar, offers a pioneering framework for the restoration of severely degraded soils, bearing implications for ecological recovery and agricultural productivity alike.

Coal mining, a cornerstone activity for energy production, often leaves behind a legacy of ecological degradation. The physical and chemical disruption of soil layers results in barren land with diminished vegetation, compacted soils, reduced organic matter, and unstable microbial ecosystems. Reclamation efforts that only redeposit topsoil fail to recreate the complex biological networks essential to sustaining plant life and soil vitality. This study’s innovative approach harnesses the complementary strengths of biochar—a carbon-enriched porous material—and AMF, a fungal symbiont known for enhancing plant nutrient uptake, to restore the multifunctionality of mined soils.

Biochar is produced through the pyrolysis of organic biomass, such as maize straw, involving heating under limited oxygen conditions. This process yields material that is chemically reactive and physically porous, characteristics that improve soil aeration and moisture retention. Crucially, biochar provides scaffolding for microbial colonization and nutrient exchange, fundamental to reestablishing soil ecosystems. Paired with biochar, AMF such as Funneliformis mosseae colonize plant roots, establishing symbiotic exchanges that facilitate the acquisition of phosphorus, nitrogen, and water by plants in exchange for carbonated compounds.

The experimental design involved four distinct treatments applied to reclaimed coal mining soil: a control with no amendments, biochar alone, AMF alone, and a unified treatment combining biochar and AMF. Results indicated that biochar and AMF act synergistically rather than additively. The combined treatment yielded a significant reduction in soil bulk density and increased porosity, thereby fostering a more hospitable physical environment for root proliferation. Enhancements in root colonization by AMF and an increased volume of soil pores further elucidated the favorable habitat engineered by biochar.

Biochemically, the joint treatment augmented the activity of a suite of soil enzymes pivotal to nutrient cycling. Enzymes such as sucrase, β-glucosidase, urease, and cellulase showed heightened activity, signifying accelerated decomposition and nutrient mineralization processes. These alterations reflect a potent reactivation of the soil’s biochemical machinery, enhancing carbon, nitrogen, and phosphorus turnover rates required for sustained plant growth and soil fertility in previously sterile substrates.

Microbial community profiling revealed a remarkable shift in both bacterial and fungal biodiversity under the combined treatment. There was an increase in species richness and evenness, fostering a more resilient and functional microbiome. Stress-tolerant and nutrient-cycling microbial taxa flourished, closely tied to the improved physical and chemical soil conditions mediated by biochar and AMF. This microbial rejuvenation is critical for sustaining nutrient fluxes and maintaining soil ecosystem services in reclaimed mining lands.

One of the central metrics assessed was soil multifunctionality, an integrative indicator encompassing structural integrity, nutrient cycling capability, microbial community robustness, and agricultural viability. The combined biochar-AMF treatment demonstrated the highest multifunctionality scores, underscoring the effective restoration of diverse soil functions. A sophisticated random forest model analysis identified nutrient supply as the dominant driver of multifunctionality, while enzyme-driven molecular activity was the prime determinant of maize yield, linking soil biochemical vitality directly to crop performance.

The study highlights an intricate network whereby biochar improves soil habitat quality, facilitating AMF colonization and root development, which in turn amplifies nutrient acquisition by the plant. This tripartite relationship between plants, fungi, and biochar creates a feedback loop that rebuilds soil fertility and health from the ground up. Such an ecosystem engineering approach underscores the potential for integrating microbial inoculants with soil amendments to accelerate land restoration beyond conventional reclamation techniques.

Furthermore, the practical implications of this work are significant. Mine reclamation sites typically suffer from poor fertility, soil compaction, and fragile microbial populations that hamper sustainable agriculture. Deploying a combined strategy of biochar and AMF inoculation could transform these marginal lands into productive soils capable of supporting robust crop yields and wider ecological restoration goals, aligning with global sustainability agendas that prioritize nature-based solutions.

This research also aligns with a broader understanding that long-term sustainability of post-mining landscapes hinges on restoring biological processes rather than merely physical and chemical soil properties. The microbial and enzymatic pathways revitalized by biochar and AMF are fundamental to soil resilience and resistance against ongoing environmental stresses such as drought or nutrient depletion.

As such, this study represents a paradigm shift in land reclamation science, advocating for integrated biotic and abiotic approaches to soil restoration. It not only demonstrates empirical successes in a harsh mining reclamation context but invites future exploration into the scalability, cost-effectiveness, and ecological ramifications of combining biochar and microbial agents across diverse environments.

In summary, the synergistic application of biochar and arbuscular mycorrhizal fungi offers a scientifically grounded and ecologically sound method to restore multifunctionality in mined soils. By fostering improved nutrient supply, enhancing soil structure, stimulating enzymatic activity, and reshaping microbial communities, these nature-based interventions promise a new horizon for sustainable agriculture and ecosystem revival on lands once deemed lost.

News Publication Date: 3-Jun-2026

Web References:
DOI link

References:
Dong, Y., Yang, L., He, X. et al. Synergistic enhancement of soil multifunctionality by biochar and arbuscular mycorrhizal fungi via improved nutrient supply in coal mining reclaimed soils. Biochar 8, 104 (2026).

Keywords

Soil restoration, biochar, arbuscular mycorrhizal fungi, coal mining reclamation, soil multifunctionality, microbial diversity, nutrient cycling, soil enzymes, plant-fungal symbiosis, environmental remediation, sustainable agriculture, soil health