Influence of Tree Species on Soil Nutrients Status in Murke Grassland and Nkafamiya Montane Soils of Adamawa State, Nigeria

Abstract

This study assessed soil physicochemical properties in grassland, and montane ecosystems in Adamawa State, Nigeria. Soil samples were collected at 0-20 cm (surface) and 20-50 cm (subsurface) depths from each ecosystem, analyzing physical properties (texture, bulk density, particle density, and total porosity and key nutrient indicators (soil organic carbon, soil organic matter, total nitrogen, available phosphorus, pH, electrical conductivity, exchangeable cations [Ca, Mg, Na, K]). The influence of plant species (Tamarindus indica, Adansonia digitata, Vitellaria paradoxa) on these properties was also evaluated. Results showed significant variations across ecosystems. Soil texture varied from sandy loam to loamy sand, montane soils had the highest clay (up to 17.8%) and lowest bulk density (0.90 g/cm³). Grassland soils showed higher bulk density (up to 1.55 g/cm³) and Potassium (up to 1.27 cmol/kg). Montane ecosystem exhibited the highest soil organic carbon (up to 1.55%), soil organic matter (up to 2.67%), and Total nitrogen (up to 0.15 mg/kg) while grassland had the lowest (soil organic carbon as low as 0.05%, soil organic matter as low as 0.03%, Total nitrogen as low as 0.01 mg/kg). These differences were attributed to favorable environmental conditions in montane and ecosystem. Grassland soils were slightly alkaline (pH up to 7.69), contrasting with acidic montane soils (pH as low as 6.11). Higher soil organic carbon in montane ecosystem increased effective cation exchange capacity (ECEC), while low organic matter in grasslands explained their reduced nutrient status. Exchangeable cations varied, with montane soils having the highest Ca (up to 6.00 cmol/kg) and Exchangeable cations (up to 0.25 dS/m), and grasslands the highest Na (up to 0.78 cmol/kg) and Potassium.