Baseline Assessment of Soil Physico-Chemical Parameters and Macro-Invertebrate Distribution Across Urban and Agricultural Matrices in Punjab, Pakistan

Abstract Purpose: Understanding the quantitative relationship between edaphic factors and soil fauna is vital for regional soil health monitoring. This study provides an empirical baseline assessment of soil physico-chemical parameters and macro-invertebrate (earthworm) abundance across four distinct urban and agricultural land-use matrices in Punjab, Pakistan. Methods: Using a stratified random sampling design across four sites (LCWU Ground, an agricultural sugarcane field in Pattoki, Lawrence Gardens, and a site near Sagian Bypass), soil samples were collected in five replicates per site. Soil depth cores (6 inches) were evaluated for earthworm counts. Standard laboratory methods were employed to quantify organic matter (titration), moisture content (gravimetric), pH, electrical conductivity (EC), and available phosphorus (spectrophotometric acid digestion). Results: Earthworm abundances varied significantly across matrices, ranging from means of 1.8 ± 0.8 at LCWU to 7.8 ± 0.65 in the agricultural sugarcane field. Organic matter percentages exceeded standard agricultural thresholds across all sites. Correlation analysis revealed a strong positive relationship between organic matter and earthworm abundance (r = 0.8811), whereas moisture content (r = -0.1116), pH (r = 0.0523), electrical conductivity (r = -0.0598), and available phosphorus (r = -0.2930) exhibited weak or negative correlations with earthworm numbers. Conclusion: Soil organic matter serves as a primary reliable indicator for regional earthworm population distribution. While these empirical baselines offer valuable insights for sub-tropical land-use management, multi-season studies are recommended to further investigate mechanistic biochemical pathways.