Interactive Effects of Agroecological Zones and Land Use on Heavy Metal Distribution and Arbuscular Mycorrhizal Fungal Responses in Tropical Agricultural Soils of Southwestern Nigeria
Description
Dataset Description and Research Hypothesis This dataset examines the influence of agroecological zone and land-use system on heavy metal distribution and arbuscular mycorrhizal fungal (AMF) spore density in tropical agricultural soils. The study hypothesized that agroecological conditions and land-use history would influence Pb, Cd, and As concentrations and AMF abundance, and that heavy metal concentrations may be associated with AMF responses. Soil samples were collected from two agroecological zones in southwestern Nigeria (Rainforest and Derived Savannah) across three land-use systems: cocoa plantation, arable farmland, and undisturbed/control sites. The dataset contains measurements of soil Pb, Cd, and As concentrations and AMF spore density, together with relevant soil physicochemical properties. Pb concentration was significantly associated with agroecological zone (p = 0.0131), with higher concentrations in Rainforest soils. Cd was significantly associated with land-use system (p = 0.0223), with higher concentrations in cocoa soils than control soils. As showed a significant agroecological zone × land-use interaction (p = 0.00167), with the highest concentrations in Rainforest cocoa soils. AMF spore density also showed a significant zone × land-use interaction (p = 0.0139), with the greatest abundance in Rainforest cocoa soils. However, Pb, Cd, and As concentrations did not significantly predict AMF spore density (R² = 0.0103, p = 0.871), indicating that AMF abundance was not explained by individual metal concentrations alone. Overall, the data suggest that heavy metal distribution and AMF responses are shaped by the broader ecological and land-use context. The dataset can be used for analyses of heavy metal accumulation, AMF responses, soil quality, land-use effects, and agroecological variation in tropical agricultural systems.
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Soil samples were collected from two agroecological zones in southwestern Nigeria (Rainforest and Derived Savannah) and three land-use systems (cocoa, arable farmland, and undisturbed/control sites). Samples were collected, labelled, transported to the laboratory, and processed for soil physicochemical properties, Pb, Cd, and As concentrations, and AMF spore density. Heavy metals were determined using standard soil digestion and instrumental analytical procedures, while AMF spores were extracted by wet-sieving and decanting and counted microscopically. The data were organized by agroecological zone and land-use system, with replicate observations retained. Statistical analyses, including analysis of variance, post-hoc comparisons, Pearson correlation, and regression, were used to evaluate differences and relationships among the variables. Analyses and data visualization were performed using R statistical software.