Correlation of Soil Quality Properties in a Tree Biosphere: A Case Study of Burnt and Unburnt Hevea brasiliensis Plantations

Aim of study: The study examined the correlations of soil quality properties in a tree biosphere: a case study of burnt and unburnt Hevea brasiliensis plantations.Area of study: The research was conducted in burnt and unburnt Hevea brasiliensis plantations in Edo State, Nigeria.Material and method: Soil samples were collected from sampled areas within the burnt and unburnt rubber plantations using the grid sampling method. Samples were obtained from both topsoil and subsoil layers and analyzed for soil properties using standard soil analytical procedures. The Pearson Product Moment Correlation (PPMC) statistical technique was used to determine correlations among soil quality properties.Main results: Soil pH showed a significant positive correlation with calcium (Ca) (0.68), magnesium (Mg) (0.76), potassium (K) (0.73), iron (Fe) (0.76), zinc (Zn) (0.76), copper (Cu) (0.73), manganese (Mn) (0.69), and clay (0.67) at p < 0.05, and with exchangeable acidity (EA) (0.61) and effective cation exchange capacity (ECEC) (0.62) at p < 0.01 in the topsoil of the unburnt rubber plantation. Silt showed a significant negative correlation with sand (-0.81) at p < 0.05 and with K (-0.63), Cu (-0.63), and Mn (-0.63) at p < 0.01 in the subsoil. Soil organic matter (SOM) revealed a significant positive correlation with total organic carbon (TOC) (0.96) at p < 0.05 in the topsoil of the burnt rubber plantation. Zinc (Zn) demonstrated a significant negative correlation with phosphorus (P) (-0.61) at p < 0.01 in the topsoil of the burnt rubber plantation. Clay showed a significant positive correlation with pH (0.67), EA (0.64), and ECEC (0.68) at p < 0.05 and with K (0.60) and Cu (0.60) at p < 0.01 in the topsoil of the unburnt site. Total heterotrophic bacteria count (THBC) indicated a significant positive correlation with Fe (0.95) at p < 0.05 in the topsoil of the burnt rubber plantation. THBC also showed significant positive correlations with Ca (0.74), Mg (0.83), Na (0.83), K (0.74), Fe (0.82), Zn (0.69), Cu (0.74), and Mn (0.74) at p < 0.05 in the subsoil.Research highlights: The study revealed significant relationships among soil properties, which have important implications for soil quality management in burnt and unburnt rubber plantations. The findings also provided reliable empirical data on soil quality properties that can support precision agriculture and aid in the establishment and management of rubber plantations.