Sustainable Practices for Restoring Cocoa Farm land in Gold Mining-Damaged Agricultural Lands in South West Nigeria

Research Hypothesis
The hypothesis of this study is that biochar and inorganic amendments significantly improve soil health, cocoa growth, and biodiversity in gold mining-impacted agricultural lands compared to untreated control plots.
Description of the Data
The dataset includes field data collected over 12 months from two gold mining-impacted agricultural sites (Aba Ooni and Aye Isale) in Osun State, Nigeria. The study employed a randomized complete block design with three treatments: biochar, inorganic amendments (NPK and lime), and a control. The dataset comprises:
1. Soil Parameters: Soil pH, organic matter content, macronutrients (N, P, K, Ca, Mg), and heavy metal concentrations (Hg, Pb, Cd).
2. Cocoa Growth Parameters: Plant height, stem diameter, leaf area index, and plant vigor scores.
3. Biodiversity Metrics: Plant and pollinator species counts and Shannon-Wiener Diversity Index.
Key Findings
1. Soil Health Improvement:
o Biochar significantly improved soil pH (6.2 ± 0.2) and organic matter (2.8 ± 0.1%) compared to control and inorganic amendments.
o Biochar reduced heavy metal concentrations (e.g., Hg: 0.12 ± 0.01 mg/kg vs. 0.65 ± 0.02 mg/kg in control).
o Inorganic amendments were effective but less impactful than biochar.
2. Cocoa Growth Enhancement:
o Biochar-treated cocoa plants showed the greatest height (78 ± 4.2 cm) and stem diameter (4.0 ± 0.3 cm).
o Leaf area index and plant vigor scores were highest in biochar plots, indicating enhanced photosynthesis and overall health.
3. Biodiversity Improvements:
o Biochar-treated plots had the highest biodiversity, with 18 ± 1.5 plant species and 9 ± 0.7 pollinator species.
o The Shannon-Wiener Index was highest in biochar plots (2.5 ± 0.2), reflecting improved ecosystem stability.
Data Interpretation and Usage
• Soil Restoration: The data highlights biochar’s superior ability to rehabilitate degraded soils, especially in mitigating acidity and heavy metal contamination.
• Cocoa Productivity: Growth metrics show that biochar improves cocoa plant development through better nutrient availability and soil structure.
• Ecosystem Health: Biodiversity metrics emphasize the role of biochar in enhancing ecological balance, making it a sustainable agricultural amendment.
Applications
Researchers and agricultural practitioners can use this dataset to:
• Develop sustainable soil restoration strategies in mining-impacted areas.
• Optimize biochar and inorganic amendment applications for cocoa farming.
• Assess biodiversity as an indicator of agroecosystem health.
The findings affirm biochar’s effectiveness in soil remediation and agroecological restoration, supporting its adoption for sustainable agricultural practices.