Assessment of tyre burning impact on forest soil mineral nutrients in Arakanga Forest Reserve, Southwestern Nigeria

Abstract

Soil nutrients are needed for healthy forest growth. Forest soils were assessed at two different sites and depths (0-30cm and 30-60cm) within Arakanga Forest Reserve (AFR) to determine the effects of tyre burning on the mineral nutrient concentration of the soil. The two sites include the tyre burning part of the reserve (Site 1) and control site (Site 2). The AFR is a forest reserve in Ogun state, Nigeria that falls under the purview of a peri-urban forest. A 4x2 factorial experiment was laid out in a Randomized Complete Block Design (RCBD). Soil samples were randomly collected in each site at different depths and taken to the laboratory for further analysis. The trend for macronutrients in Sites 1 and 2 was as follows K>Mg>Na>Ca. Site 1 had a higher Sodium and Calcium at 0-30cm depth though there was no significant difference (p≥0.05) in their concentration between depths and sites. Potassium and Magnesium at both depths and sites varied significantly (p≥0.05). The order of concentration of micro-nutrients in Sites 1 and 2 include; Fe>Zn>Mn>Cu and Zn>Fe>Cu>Mn respectively. Copper, Iron, Zinc and Manganese concentrations were higher at 0-30cm depth in Site 1. Soil properties such as Organic Carbon, Organic matter, Total Nitrogen and Available Phosphorus were higher at 0-30cm; Bulk density and porosity were higher at 30-60cm depth and also varied between sites. Proper protection of the forest reserve from scavengers who illegally burn tyres to extract tiny steel wires should be enforced to sustain healthy forest growth.