COMPARATIVE ASSESSMENT OF SOIL PHYSICOCHEMICAL PROPERTIES, NUTRIENT AVAILABILITY, AND SALINITY-ALKALINITY CONSTRAINTS IN AGRICULTURAL SOILS OF MASTUNG AND MUSAKHEL DISTRICTS, BALOCHISTAN

Abstract

Assessment of soil physicochemical properties is fundamental for evaluating soil fertility and developing sustainable nutrient management strategies in arid and semi-arid agroecosystems. This study investigated the physicochemical characteristics of agricultural soils from the Mastung and Musakhel districts of Balochistan, Pakistan, to evaluate soil fertility status and identify major constraints limiting crop production. Soil samples were collected from three depths 0–10, 10–20, and 20–30 cm and analyzed for soil texture, pH, electrical conductivity, soil organic matter, soluble calcium and magnesium, carbonate, chloride, sodium, available potassium, and phosphorus.

The results revealed significant differences (P < 0.05) in soil physicochemical properties between the two districts and across soil depths. Mastung soils ranged from silt loam to sandy loam and exhibited significantly higher EC (2.13–2.36 dS m⁻¹) and alkaline pH (8.60–9.35), indicating greater salinity and alkalinity than Musakhel soils. Soil organic matter declined significantly with depth (0.55–0.42%), accompanied by decreases in available K (86.99–59.42 mg kg⁻¹), P (4.36–2.28 mg kg⁻¹), and Na (63.21–42.03 mg kg⁻¹), whereas CO₃²⁻ and Cl⁻ increased in the subsoil. In contrast, Musakhel soils were predominantly sandy loam with comparatively lower EC (0.74–1.27 dS m⁻¹) and pH (7.58–8.13), reflecting more favorable conditions for crop production. Potassium concentrations remained considerably higher (131.35–151.64 mg kg⁻¹), while phosphorus was consistently low (1.80–4.45 mg kg⁻¹), indicating phosphorus deficiency in both districts despite marked differences in salinity status.

Overall, Mastung soils are primarily constrained by alkalinity, moderate salinity, low organic matter, and nutrient depletion, whereas Musakhel soils exhibit comparatively better physicochemical quality and greater potassium availability. These findings provide baseline information for site-specific soil fertility management and sustainable agricultural planning aimed at improving crop productivity in the arid and semi-arid regions of Balochistan.