Key Takeaways & Executive Findings
- •• • Microbial fertilizer (MF) significantly increased soil total carbon (TC) from 8.47 to 10.17 g·kg⁻¹ and total nitrogen (TN) from 0.37 to 0.56 g·kg⁻¹, representing a 20.1% and 51.4% increase, respectively, which is critical for establishing a carbon and nitrogen pool in nutrient-poor mine soils. • • High-phosphorus inorganic fertilizer (H) raised available phosphorus (AP) from 9.78 to 26.28 mg·kg⁻¹, a 168.7% increase, directly addressing severe phosphorus limitation (initial AP < 10 mg·kg⁻¹) that constrains plant establishment. • • Both MF and H treatments significantly altered fungal community structure, notably increasing the relative abundance of Gibberella and Alternaria, indicating that nutrient-driven shifts in microbial communities are key mechanisms for enhancing nutrient availability. • • MF treatment achieved these improvements without the ecological risks associated with high inorganic P application (e.g., soil acidification, pathogen proliferation), positioning it as a sustainable bio-based strategy for mine reclamation.
Abstract
Open-pit coal mining causes severe soil nutrient depletion, limiting vegetation restoration. This study, conducted in the Baiyinhua No.2 mining area (Inner Mongolia), evaluated the effects of different fertilization strategies on soil nitrogen (N) and phosphorus (P) availability and microbial community responses. A field experiment was established in May 2023 with five treatments: low (L), medium (M), and high (H) phosphorus inorganic fertilizers, green manure (GM), and a microbial fertilizer (MF) containing nitrogen-fixing and rhizobia bacteria, compared to a control (CK). Results showed that MF significantly increased total carbon (TC) from 8.47 to 10.17 g·kg⁻¹ and total nitrogen (TN) from 0.37 to 0.56 g·kg⁻¹, while H significantly increased available phosphorus (AP) from 9.78 to 26.28 mg·kg⁻¹. Both treatments significantly altered fungal community structure, with increased relative abundances of Gibberella and Alternaria. The study concludes that MF and H improve soil nutrient availability by modulating fungal communities, with MF offering a sustainable biological approach for mine reclamation. These findings provide targeted fertilization strategies for restoring degraded mining soils and advancing green mining practices.
1. Introduction
Open-pit coal mining leaves behind vast areas of nutrient-depleted soil, severely limiting vegetation recovery and ecosystem restoration. Traditional inorganic fertilizers provide rapid nutrient release but often fail to improve soil structure and can induce acidification, harming microbial communities. Green manure offers organic matter but cannot rapidly enhance microbial diversity in severely degraded soils. These limitations create a critical bottleneck: how to effectively restore soil fertility and microbial function in mine soils within a practical timeframe.
This study addresses this bottleneck by comparing low, medium, and high phosphorus inorganic fertilizers, green manure, and a microbial fertilizer containing nitrogen-fixing and rhizobia bacteria in the Baiyinhua mining area. The microbial fertilizer is hypothesized to improve soil nutrient availability by directly introducing beneficial microorganisms that enhance nutrient cycling and reshape fungal communities. The high-phosphorus treatment is expected to rapidly elevate available phosphorus, but may carry ecological risks. By quantifying changes in soil carbon, nitrogen, phosphorus, and fungal community structure, this research identifies effective fertilization strategies and their microbial mechanisms, providing evidence-based guidance for mine reclamation and sustainable ecosystem management.
Loading authentic research manuscript (Pages 1–5)...
SUN Guohao, LI Jingguo, QU Laiye, GOU Tienan, JIA Hongjun, YANG Ziyu, ZHANG Naili (2026). Effects of Different Fertilization Treatments on Soil Nutrient Availability and Microbial Response Mechanisms in the Baiyinhua Open-Pit Mining Area. Chinese Journal of Environmental Engineering. https://doi.org/10.12030/j.cjee.202505106
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What are the long-term ecological risks of high-phosphorus inorganic fertilizer application in mine soils, and how does the microbial fertilizer mitigate these risks?
High-phosphorus inorganic fertilizer (H) increased available phosphorus to 26.28 mg·kg⁻¹, but such high P levels can lead to soil acidification and potential eutrophication if runoff occurs. Additionally, the observed increase in Alternaria, a potential plant pathogen, suggests a risk of pathogen proliferation. In contrast, microbial fertilizer (MF) improved total nitrogen and carbon without elevating available phosphorus, and while it also increased Alternaria, the overall nutrient balance and reduced chemical input lower the ecological footprint. Long-term monitoring is needed to assess pathogen dynamics and soil health.
How does the microbial fertilizer achieve a 51.4% increase in total nitrogen, and what is the contribution of biological nitrogen fixation versus other mechanisms?
The microbial fertilizer contains nitrogen-fixing bacteria and rhizobia, which can convert atmospheric nitrogen into plant-available forms. The observed increase in total nitrogen from 0.37 to 0.56 g·kg⁻¹ likely results from enhanced biological nitrogen fixation, as well as improved root growth and organic matter accumulation. However, the exact contribution of each mechanism requires isotope labeling studies (e.g., ¹⁵N dilution) to quantify. The concurrent increase in total carbon suggests that microbial activity also enhanced carbon sequestration, possibly through increased plant biomass and root exudates.
What are the scalability and cost implications of using microbial fertilizer for large-scale mine reclamation compared to inorganic fertilizers?
Microbial fertilizer production involves cultivating specific bacterial strains, which can be more costly per unit than synthetic inorganic fertilizers. However, the benefits include reduced need for repeated applications due to improved soil health, and lower environmental remediation costs. For large-scale application, production can be scaled using industrial fermentation, and costs may decrease with technological advancements. A cost-benefit analysis should consider long-term ecosystem recovery and reduced chemical inputs. Initial trials on smaller plots are recommended to optimize application rates and assess economic viability.
How do the changes in fungal community structure, particularly the increase in Gibberella and Alternaria, affect plant health and soil function?
Gibberella includes species that can cause plant diseases, while Alternaria is a common saprophyte and opportunistic pathogen. Their increased relative abundance may indicate a shift towards decomposer communities, which is beneficial for nutrient cycling. However, some species could pose risks to plant health. The study did not measure plant disease incidence, so the functional impact is unclear. Future research should isolate and characterize these fungi to determine their pathogenic potential and role in nutrient turnover. The overall positive effect on soil nutrients suggests that the benefits outweigh potential risks, but careful monitoring is advised.
What are the optimal application rates and timing for microbial fertilizer to maximize nutrient availability and microbial benefits in mine soils?
This study applied microbial fertilizer at a single rate, and the results showed significant improvements in total carbon and nitrogen. To determine optimal rates, a dose-response experiment is needed, testing multiple application levels (e.g., 50%, 100%, 150% of the tested rate). Timing is also critical; application during the growing season (May-June) when soil moisture and temperature are favorable for microbial activity is recommended. The study's application in May 2023 with sampling in August suggests that effects were evident within three months, but longer-term studies are needed to assess persistence and optimal reapplication intervals.
Related Chinese Research & Cross-Citations
Analysis of National and Local Policies for Medical Waste Treatment and Disposal in China
The escalating generation of medical waste, driven by healthcare expansion and frequent medical activities, poses significant environmental and public health risks. Under the framework of ecological civilization, China is developing a comprehensive policy system for medical waste treatment and disposal, yet the current framework remains nascent and exhibits inconsistencies between national and local policies. This study systematically analyzes the status of national and local policies from 2003 to 2024, collecting 413 policy documents (166 from national ministries and 247 from provincial governments). The analysis examines temporal evolution, regional distribution, and policy focus, alongside the influence of medical waste output, treatment technologies, facility infrastructure, and major epidemic responses. Findings reveal distinct policy phases: initial self-disposal, exploratory management, foundational system building, and rapid development. Regional disparities are pronounced, with eastern coastal areas showing more advanced policies due to greater technical and financial resources. The surge in medical waste, particularly during the COVID-19 pandemic, underscores the need for enhanced regulatory guidance. Non-incineration technologies are gaining traction for their environmental and cost benefits, and facility coverage has improved but remains uneven. The study proposes five policy principles to foster technological innovation and industrial upgrading, ensuring safe medical waste management and environmental protection.
Kinetic Analysis and Simulation of Pollutant Removal in Sewage Networks
This study investigates pollutant removal characteristics and kinetic behaviors in sewage networks, and analyzes their impact on the carbon-to-nitrogen ratio (C/N, as COD/TN) of influent to wastewater treatment plants. Source water quality sampling at drainage outlets revealed spatial and temporal variations in C/N, with domestic sewage exhibiting higher C/N than industrial sewage, and diurnal peaks reaching 6.92 versus 4.71 during off-peak hours. Using a pilot-scale adjustable sewage network system in Kunshan, experiments were conducted under high (0.491 m·s−1) and low (0.089 m·s−1) flow velocities, monitoring pollutant removal over 144 hours. Pseudo-first-order kinetics were applied to model COD and TN removal. Results showed that COD (including SCOD and PCOD), BOD5, and SS achieved approximately 80% removal within 144 h, with higher removal at low flow velocity. TN, NH3-N, and TP exhibited lower overall removal rates. Kinetic fitting revealed that COD removal rate constants (kCOD) were significantly higher than those for TN (kTN), and both decreased with increasing flow velocity: at low velocity, kCOD=0.0167 h−1 and kTN=0.0029 h−1; at high velocity, kCOD=0.0127 h−1 and kTN=0.0020 h−1. Simulations based on actual source pollutant concentrations indicated that the time for C/N to drop to the denitrification critical value of 4.50 was 12.24 h at high velocity, but shortened to 9.49 h at low velocity. These findings demonstrate that increasing flow velocity effectively retards the decline of C/N. Therefore, regulating network flow velocity to reduce hydraulic retention time is a key strategy for maintaining adequate C/N at the terminal and ensuring denitrification efficiency in wastewater treatment plants.
Preparation of Trimetallic-Carbon Composite Catalysts and Their Application in Catalytic Ozonation of Industrial Wastewater
Advanced oxidation processes (AOPs) are promising for degrading organic pollutants in water treatment. Heterogeneous catalytic ozonation (HCO) has gained attention due to its high oxidation efficiency, strong interference resistance, and low secondary pollution. In this study, a series of trimetallic-carbon composite ozone catalysts were prepared via an organic precursor calcination method using γ-Al2O3 as support. This method enhanced catalytic activity and mechanical strength while overcoming the limitations of carbon materials (low mechanical strength) and metal-based materials (poor mass transfer). The optimized catalyst, CA-FeCoCu, comprising Fe, Co, Cu, carbon, and alumina, exhibited excellent performance in phenol degradation and real industrial wastewater treatment. Characterization revealed that the synergistic effect of trimetals and the introduction of multiple carbon types increased specific surface area and hydroxyl radical (·OH) generation. In a pilot-scale fixed-bed reactor, the CA-FeCoCu/O3 system reduced COD from 120 mg·L−1 to below 40 mg·L−1, with an O3 consumption ratio (O/C) of less than 1, effectively lowering operational costs. This work provides a new strategy for developing efficient and stable heterogeneous O3 catalysts and offers a reference for the practical application of HCO in industrial wastewater treatment.
Differentiated Characteristics of Suspended Particulate Matter and Their Effects on Water Quality in the Middle and East Routes of the South-to-North Water Diversion Project
This study investigates the spatiotemporal differentiation of suspended particulate matter (SPM) characteristics, sources, and their impacts on water quality between the Middle Route (closed artificial channel) and East Route (open natural water system) of the South-to-North Water Diversion Project. Thirty sampling sites (13 on the Middle Route, 17 on the East Route) were established, and samples were collected during dry and wet seasons. Water quality parameters and SPM characteristics were analyzed, including particle size distribution, total suspended solids (TSS), chlorophyll a, and stable carbon and nitrogen isotopes. Results show that the Middle Route maintains good and stable water quality, with SPM dominated by coarse particles (>63 μm, 61.43%–94.68%), total phosphorus (TP) <0.01 mg·L−1, and a significant positive correlation between chlorophyll a and coarse particles (r=0.60), indicating algal aggregation dominates particle formation. In contrast, the East Route exhibits high and fluctuating nitrogen and phosphorus concentrations, with SPM dominated by fine particles (<20 μm, 51.26%–88.61%), TP ranging from 0.03 to 1.11 mg·L−1, and a positive correlation with fine particles, suggesting significant external inputs. Carbon and nitrogen isotope analysis reveals that Middle Route SPM primarily originates from autochthonous algae (contribution >46.75%), while East Route SPM is influenced by both terrestrial C3 plants and algae. The distinct engineering and management approaches of the two routes lead to significant differences in SPM characteristics and sources, thereby affecting water quality dynamics. The Middle Route requires an 'algal reduction and hydrodynamic optimization' strategy to control algal-derived coarse particle deposition, whereas the East Route benefits from 'retention-sedimentation and wetland purification' to reduce external fine particles and pollutant inputs. This research provides theoretical support and practical guidance for differentiated SPM management in long-distance water diversion systems.
Combined Ozone Micro-Nano Bubble Oxidation and Powdered Activated Carbon Adsorption for Removal of Taste and Odor Compounds from Drinking Water
Algal-derived taste and odor compounds (2-methylisoborneol, 2-MIB, and geosmin, GSM) in drinking water sources are poorly removed by conventional treatment. This study systematically evaluated the standalone and combined performance of ozone micro-nano bubbles (O3-MNBs) oxidation and powdered activated carbon (PAC) adsorption for removing 2-MIB, GSM, and algal cells from source water. Results showed that O3-MNBs pre-oxidation achieved >97.5% removal of odorants at 400 ng·L−1 and 67.2% algal cell removal within 30 min. When applied as a deep treatment stage, the degradation rate constant (k) was 10.1%–25.6% higher than in pre-oxidation due to lower background matrix interference. Both pre-oxidation and deep treatment reduced effluent concentrations of 2-MIB and GSM to below 10 ng·L−1, with oxidation kinetics fitting pseudo-first-order models (R²>0.95). PAC adsorption of both compounds followed pseudo-second-order kinetics (R²>0.99), with GSM equilibrium adsorption capacity approximately 20.0% higher than that of 2-MIB. In pure water, adsorption capacity increased by >10.0% compared to raw water. Based on kinetic models, a quantitative prediction method was established for O3-MNBs oxidation and PAC adsorption processes, aiming to achieve efficient odorant removal and cost optimization, providing theoretical support for advanced drinking water purification and smart water plant construction.
Pulsed Electric Field Enhancement of Nitrogen Removal Performance and Microbial Community Structure Response in Anammox Granular Sludge
This study investigated the effects of a ring-shaped pulsed electric field (PEF) (1.5 V, 4 h on-time per cycle) on nitrogen removal performance and microbial community structure of anammox granular sludge (AnGS). Two anaerobic sequencing batch reactors (R1 control, R2 with PEF) were operated under stepwise increasing nitrogen loading rates (NLR). At NLR below 1,155 mg·(L·d)−1, R2 exhibited total nitrogen removal efficiency (TRE) 7.5%–17.0% higher than R1, with biomass, specific anammox activity (SAA), and extracellular polymeric substances (EPS) increased by 5%–7%, 21%–71%, and 54%–77%, respectively. However, at NLR above 1,320 mg·(L·d)−1, the toxic effect of nitrite dominated, and PEF enhancement diminished or even reversed to inhibition. Microbial community analysis revealed that at low-to-moderate NLR, PEF increased the relative abundance of Planctomycetes and key anammox bacteria (Candidatus Brocadia and Candidatus Jettenia), along with enhanced community richness (Chao1) and diversity (Shannon/Simpson indices). At high NLR, PEF decreased microbial richness compared to R1. Principal component analysis and redundancy analysis indicated that PEF was the key factor driving community differences at low-to-moderate NLR, whereas nitrite concentration became the dominant factor at high NLR. This study provides theoretical support for enhancing the resilience and engineering application of anammox processes.