Table 2_Coupled salinity, nutrient, and trace-element patterns in arid agricultural soils of hail, Saudi Arabia: an integrated laboratory–GIS screening assessment.xlsx

Average shale concentrations were used as reference values for screening-level contamination assessment.</p>Results<p>Five interrelated process domains were identified: salinity–sodicity, carbonate–alkalinity buffering, nutrient and agronomic enrichment, lithogenic background, and trace-element/metalloid mobility. After exclusion of one non-physical pH result, pH ranged from 7.68 to 9.00 (median: 8.20). Electrical conductivity ranged from 595 to 54,700 μS cm⁻¹ whereas total dissolved solids ranged from 380 to 46,200 mg kg⁻¹.

Electrical conductivity was strongly correlated with total dissolved solids (r = 1.00), alkalinity/HCO₃⁻ (r = 0.99), Cl⁻ (r = 0.94), F⁻ (r = 0.97), and NO₃⁻ (r = 0.80), indicating apparent salt–nutrient coupling within the analytical matrix. Map-derived principal components PC1, PC2, and PC3 explained approximately 42%, 25%, and 11% of the spatial-pattern variance, respectively.

PC1 represented a salt–nutrient accumulation axis, whereas PC2 reflected parent-material and heavy-mineral influences. Average-shale screening of 29 complete eight-element records yielded pollution load index values of 0.07–0.31 (median: 0.12). Twenty-eight records were classified as having low ecological risk, while Soil-29 exhibited moderate risk (RI = 296), driven predominantly by Cd.

No composite PLI or RI was assigned to Soil-26 because its negative Cd result was identified as a non-physical analytical artifact.</p>Discussion<p>The findings indicate that Hail soil chemistry reflects coupled irrigation, evaporative, agronomic, buffering, and lithogenic controls rather than independent elemental distributions. Because complete batch-specific analytical and QA/QC records were unavailable, the results constitute screening-level evidence and should not be interpreted as regulatory, bioavailability, or human-health-risk classifications.

The integrated framework provides a basis for prioritizing confirmatory sampling, improving salinity management, and developing locally representative geochemical baselines for arid irrigated landscapes.</p>