Assessment of soil fertility status based on NPK levels: A case study at agricultural research farm, Malakandher, Peshawar

Abstract

This study aims to evaluate the fertility status of soils at the Agricultural Research Farm, Malakandher, Peshawar, focusing on key macronutrients and physicochemical properties affecting crop productivity. Soil samples (0-15 cm depth) were collected from twelve representative farm blocks and analyzed for nitrogen, phosphorus, potassium, organic matter, soil pH, and electrical conductivity using standard laboratory procedures. The Kjeldahl method was used for nitrogen estimation, AB-DTPA extraction for phosphorus and potassium, Walkley-Black method for organic matter, and saturation extract techniques for pH and electrical conductivity. Results indicated significant variability in nutrient levels across fields: nitrogen ranged from 0.12% to 0.29%, phosphorus from 0.43 to 3.01 mg/kg, potassium from 97.5 to 151.9 mg/kg, and organic matter from 0.80% to 1.10%. Soil pH was moderately alkaline (7.08 to 7.29), while electrical conductivity values (0.53 – 0.66 dS/m) were generally sufficient. The findings suggest that while nitrogen and potassium levels are generally adequate, phosphorus deficiency requires attention. This study underscores the need for uniform and site-specific nutrient management strategies to improve fertilizer recommendations, enhance soil fertility, and support sustainable crop production in Malakandher and similar agroecological regions.