Evaluating the impact of irrigation water quality on soil chemical properties using chemical indices and multivariate analysis in Northern Ghana

This study investigates the chemical interactions between irrigation water quality and adjacent soils across five agricultural zones in Northern Ghana: Bolgatanga, Duru, Gotinga, Libga, and Pong Tamale, over 20 years from 2000 to 2025. A total of 23 physicochemical parameters, including pH, EC, NO₃⁻, Na⁺, heavy metals, and salinity indices, were analyzed in soil and water samples using standardized laboratory protocols. Statistical analyses, such as Spearman correlation, Welch’s t-test, delta and volcano plots, were employed alongside Linear Mixed Effects Models (LMM) to assess temporal and spatial dynamics. Results show progressive accumulation of EC, NO₃⁻, and Na⁺ in soils, driven by irrigation practices and fertiliser use. EC and Na⁺ demonstrated strong water-soil linkages, while nutrients like PO₄³⁻ and Mg²⁺ showed weak correlations due to complex soil retention dynamics. LMMs revealed significant effects of water quality and time on soil parameters, with EC, NO₃⁻, and Pb emerging as key indicators of degradation. The findings underscore the need for site-specific irrigation management, improved drainage, and continuous monitoring to sustain soil health. This study offers a robust, multivariate framework for understanding soil-water interactions under long-term irrigation, providing valuable insights for sustainable agricultural practices in semi-arid regions.