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Effect of Soil Amendments on Short-Term CO2 Fluxes on Revegetated Mine Soil

Wilson Waanab Zoogah*, Mariam K. Al-Lami, Abdullah Al Moinee, Kwame Awuah-Offei, and Joel G. Burken

Department of Mining and Explosives & Department of Civil, Architectural and Environmental Engineering, Missouri S&T, Rolla, MO, *wwzyp6@mst.edu

Acknowledgments:

DOE RUN, Tambudze Tinozivashe,

Minerals Commission, Ghana, Mine Sustainability Modeling Research Group & Phytometals Research Group

Introduction:

The relationship between soil amendments and CO₂ fluxes is well-established in agricultural contexts. However, a critical knowledge gap exists regarding their impact on carbon dynamics in post-mining reclamation settings. Degraded mine soils differ significantly from agricultural soils due to:-1. Compacted structure and low porosity, 2. Altered microbial communities, 3. Extreme pH conditions, 4. Low organic matter, and 5. Limited vegetation establishment. This study aims to improve our understanding of how soil amendments influence short-term CO₂ fluxes during early stages of mine site revegetation.

Research Objective

Primary Objective: Evaluates the relationship between different soil amendment combinations (biochar, manure, woodchips, and arbuscular mycorrhizal fungi) and short-term CO₂ flux variability in revegetated mine soil. Hypothesis: Amendment type significantly influences short-term CO₂ emissions in mine soil, with organic amendments (biochar + manure) stimulating higher microbial activity and respiration.

Figure 2: Diagram of Experimental Design (15 pilot plots at the vegetated mine site illustrating design and specific amendments applied to each subplot)

Results

ANOVA-based statistical analysis showed variation in CO₂ emissions among different treatments.

Ongoing and Future Work

1. Extended Monitoring: Capture seasonal and annual dynamics.

2. Mechanistic Studies: Investigate amendment-induced changes

3. Correlation Analysis: Link fluxes to environmental variables

Methods and Experimental Design

Measurement Period: July–October 2025 (12 weeks, capturing late summer through early fall)

Instrumentation: LI-8100A Automated Soil CO₂ Flux System

  • 45 sampling points (3 collars per plot x 15 plots)
  • Measurement frequency: Weekly automated readings
  • Measurement duration: 2-minute chamber closure per reading

Conclusions and Implications

The Primary Findings: Soil amendment type significantly influences short-term CO₂ fluxes in revegetated mine soil (F(4, 442) = 14.1, p < 0.001), confirming that amendment selection has measurable impacts on carbon cycling during early reclamation stages.

This study provides preliminary insights into the effect of amendments on CO₂ ​ fluxes. The variation in CO₂​ emissions confirms that adding different soil amendments results in distinct, measurable, short-term effects on carbon cycling in revegetated mine soil. The findings and future work can be the basis of recommendations for sustainable mine reclamation practices.

Figure 4. Short-term Mean CO₂ ​Flux (μmol m−2 s−1) comparison for the different treatment groups.

Figure 3. Box plot illustrating the overall distribution of FCO₂DRY for each of the major amendment groups and control plots over the entire study period.

Key words:

Mine Revegetation, Soil Amendments, Short-term CO₂ Fluxes, and Reclamation.

Source

df

Sum of Squares

Mean Square

F-statistic

p-value

Treatment

4

87.8

21.95

14.1

< 0.001

Residuals

442

689.3

1.56

 

Table 1. Analysis of Variance for CO₂ flux across five amendment treatments on revegetated mine soil

Study site Characteristics

Location: Sweetwater Mine Site, Ellington, Reynolds County, Missouri, USA

Mine Type: Lead mining operation

Reclamation Status: Active revegetation (2-3 years post-disturbance)

Plot Dimensions: 20′ × 23′ measurement area per plot

Soil Type: Reconstructed mine soil with lime treatment

Vegetation: Soil seeded in Spring 2023 with a seed mix of native and prairie plants cover establishment

Climate: Humid continental (hot summers, cold winters)

Figure 1: LI-8100A Instrument

References:

1. Hu, J., et al. (2023). Environments, 10(2):19. 2. Bednik, M., et al. (2023). Materials, 16(21):6950. 3. Ahirwal, J., et al. (2017). Sci. Total Environ., 583:153. 4. Owiny, A.A. & Dusengemungu, L. (2024). Heliyon, 10(13):e33141. 5.Mathiba, D. S., & Awuah-Offei, K. (2015). Environmental Geotechnics, 2(3):149-158. 6. Zoogah, W.W., et al. (2026). SME Annual Conference & Expo (MinExchange), 26-028, pp. 232–246.

Statistical Model:

Yij = μ + τi + εij

where:

Yij = CO₂ flux observation

μ = overall mean flux

τi = treatment effect �(i = 1,...,5)

εij = random error

Treatment Effect Interpretation:

ANOVA-based statistical analysis showed variation in CO₂ emissions among different treatments." → should be updated to: One-way ANOVA revealed significant treatment effects on CO₂ flux (F(4,442) = 14.1, p < 0.001, η² = 0.113). L+M+W exhibited the highest mean flux (4.07 µmol m⁻² s⁻¹), 49% higher than untreated control. Tukey HSD confirmed L+M+W differed significantly from all other treatments

Amendment Effects: Mean CO2 fluxes differ between the plots with different soil amendments. This possibly indicates varied impacts on microbial activity and soil respiration.

Carbon Cycling: The observed variations provide insights into how amendments influence short-term carbon dynamics in revegetated mine soils.

Key Finding: F(4, 442) = 14.1, p < 0.001

Strong evidence that treatment type significantly affects CO₂ flux in revegetated mine soil

Statistical Analysis

  • ANOVA test to determine significant differences in short-term fluxes from plots with different soil amendments.
  • Completely Randomized Design (CRD)
  • 15 experimental plots randomly assigned to 5 treatment groups (3 replicates each).
  • Weekly measurements per collar over time (repeated measures), with total observations: n =447

Data Collection

  • CO₂ flux (μmol m⁻² s⁻¹)
  • Soil temperature (°C)
  • Soil moisture (%VWC)
  • Atmospheric pressure (kPa)

Research Questions

  • Do different amendment combinations produce significantly different CO₂ flux patterns?
  • Which amendments show the greatest impact on soil respiration?
  • How do temporal patterns vary across treatment types

Hypotheses:

H₀: μ₁ = μ₂ = μ₃ = μ₄ = μ₅ (no treatment effect)

Hₐ: At least one treatment mean differs

α = 0.05

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