Seasonal Soil Nutrients Flux in Managed Ecosystems in FCT, Abuja

Abstract The study examined seasonal variations in soil nutrient composition and heavy metal concentrations within the Sarius Palmetum Botanical Garden, a managed recreational ecosystem located in Maitama, Federal Capital Territory, Nigeria. The objectives assessed nutrient dynamics and the influence of seasonal changes on soil properties, evaluated the ecological sustainability of the garden. Soil samples were collected from six sites in both wet and dry seasons using a 50 cm × 50 cm quadrat subdivided into 10 cm × 10 cm cells, with samples taken from intersections and homogenized into composites for laboratory analysis. A total of thirty soil samples were obtained per season making it a total of sixty for both seasons and analyzed for macronutrients such as (N, P, K), soil organic matter (SOM), organic carbon (OC), exchangeable cations, textural fractions, and heavy metals (Fe, Pb, Cu, Zn, Mn) using standard laboratory procedures. Data was analyzed using descriptive and inferential statistics such as means, tables, student’s t- test and ANOVA to determine significant variations across seasons. Results revealed distinct seasonal patterns, with higher concentrations of nitrogen, phosphorus, and magnesium recorded during the wet season. N, P, Ca, records 0.40, 29.18, and 4.96 in the wet season and 0.39, 29.02 and 4.94 in the dry season respectively, while soil organic matter and organic carbon showed moderate enrichment. Exchangeable cation varied significantly across the seasons, and textural analysis indicated sandy loam clay dominance in the study area. Heavy metals such as Fe and Cu were detected but fell within permissible limits, with 5.19 (wet), 5.18(dry) and 1.90 (wet), 1.89(dry). indicating minimal contamination. The study concluded that there were seasonal variations in the soil nutrients suitable for sustainable ecological and recreational functions, emphasizing the need for continuous monitoring to preserve soil health and ecosystem stability.