Assessment of Soil Fertility Status and Nutrient Distribution in Agricultural Soils of Gusau Local Government Area, Zamfara State, Nigeria.

Abstract

Soil fertility assessment is a prerequisite for sustainable agriculture in semi-arid regions, where continuous cultivation often leads to nutrient depletion. This study evaluated the fertility status and nutrient distribution of agricultural soils in the Wanke and Mada districts of Gusau, Zamfara State, Nigeria. One hundred and twenty (120) soil samples were systematically collected from two depths (0–20 cm and 20–50 cm) and analyzed for key physicochemical properties using standard laboratory procedures. The results indicated that soil pH ranged from 6.01 to 6.16, reflecting slightly acidic conditions suitable for most tropical crops. Organic carbon (1.00–1.23%) and total nitrogen (0.09–0.11%) levels were low to moderate, suggesting a need for organic matter stabilization. Notably, available phosphorus (7.04–8.57 mg kg⁻¹) fell below critical thresholds, identifying it as a primary limiting factor. The exchange complex was dominated by calcium (Ca²⁺) and magnesium (Mg²⁺), with an effective cation exchange capacity (ECEC) of 5.63–6.20 cmol(+) kg⁻¹ and a high base saturation (75–82%). While the soils demonstrate moderate nutrient retention capacity, the deficiencies in nitrogen and phosphorus pose risks to long-term productivity. To mitigate these constraints and ensure food security in the region, the study recommends integrated soil fertility management, specifically the incorporation of organic amendments and balanced inorganic fertilizer application.