EFFECT OF LAND USE AND DEPTH ON SOIL CHEMICAL PROPERTIES OF TARABA STATE TEACHING AND RESEARCH FARM, JALINGO

This study evaluates the chemical properties of soils under different land-use types, including cultivated land, fallow land, and orchard land, with a focus on variations across soil depths. The results indicate that pH levels are lowest in cultivated land (6.02-6.23), intermediate in orchard land (6.34-6.43), and highest in fallow land (6.78-6.92), increasing with depth in all cases. Electrical conductivity (EC) values remain consistently low across all land-use types (0.11 dS/m), suggesting non-saline conditions. Organic carbon (OC) and organic matter (OM) are highest in cultivated land at 15-30 cm (11.57% and 19.95%, respectively) and lowest in fallow land at the same depth (7.58% and 13.07%, respectively). Both OC and OM decrease with depth across all land-use types, reflecting organic matter accumulation in the topsoil. Total nitrogen (TN) follows a similar trend, with the highest concentration observed in cultivated land at 15-30 cm (0.12%) and lower values in fallow and orchard lands (0.08%). Available phosphorus (AVP) is most abundant in the topsoil of cultivated land (7.12 mg/kg) and decreases with depth, while cation exchange capacity (CEC) is highest in cultivated land at 0-15 cm (6.02 cmol/kg) and lowest in fallow land at 15-30 cm (3.43 cmol/kg). Percent base saturation (PBS) shows a significant increase with depth in cultivated land (77.35% at 15-30 cm) but a decline in fallow land (53.93% at 15-30 cm). Sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) remain low across all treatments, indicating minimal sodium-related soil degradation. The findings suggest that cultivation enhances soil fertility by increasing organic matter, nitrogen, and phosphorus levels, while fallow land exhibits higher pH but lower nutrient availability. Depth-related trends indicate a general decline in fertility-related properties due to reduced organic matter and clay content. These results emphasize the impact of land use on soil quality and provide insights for sustainable soil management practices.