Hydro-chemical Assessment of Water Used for Agricultural Soil Irrigation: Case Study in the Water Area of the Three Morava Rivers in the Republic of Serbia

Abstract

This study investigates the hydrogeochemical characteristics and water quality of irrigation water from the aspect of its potential negative impact on soil salinization and the creation of maps for the spatial distribution in the area of the three Morava rivers, which includes the basin of the South, West, and Great Morava. A total of 215 irrigation water samples were tested and assessed based on the analysis of the following parameters: pH, electrical conductivity (EC), total dissolved salt (TDS), sodium adsorption ratio (SAR), and content of SO42-, Cl-, HCO3-, CO32-, Mg2+, Ca2+, Na+, K+. The results showed that the average content of ions was as follows: Ca2+ > Mg2+ > Na+ > K+ and HCO3- > SO42- > Cl- > CO32- Assessment of the suitability of irrigation water was determined by calculating the following indices: sodium percentage (Na %), residual sodium carbonate (RSC), permeability index (PI), magnesium hazard (MH), potential salinity (PS), Kelly index (KI), total hardness (TH), irrigation water quality index (IWQI). Using the irrigation water quality index (IWQI), which was assessed based on comparing irrigation water quality parameters with specific standards with one value, was determined that 95.34% of the tested samples were ranked as excellent and good, and 4.66% of samples were determined as poor and very poor. Based on the Wilcox diagram, USSL diagram, and Doneen diagram, it was concluded that most of the samples are suitable for irrigation. Using multivariate statistical techniques and correlation matrices in combination with other hydrogeochemical tools such as Piper, Chad, Hydrochemical Facies Diagram (HFE), and Gibbs diagram, the main factors associated with hydrogeochemical variability were identified. The work aims to point out to policymakers and decision-makers the use of water for irrigation of appropriate quality and the need for continuous monitoring and risk management through the establishment of tools for generating quick reports for application in real-time at the research site.