Suitability assessment of natural water in relation to irrigation and soil properties

Abstract

An investigation was carried out using 25 natural water samples from Narayanganj district, Bangladesh to examine the quality of both groundwater and surface water in relation to pollution and the suitability of these waters for irrigation. High concentrations of Na, Ca, Mg, HCO3, and Cl ions were recorded in all the tested samples. Significant variations in the values of electrical conductivity (EC), total dissolved solids (TDS), and major ions were observed. Some samples contained high levels of EC (0.184 to 1.624 dS m-1 at 25°C) that revealed the presence of soluble salts which could cause crust formation and seal development of the soil profile due to the chemical and mechanical action of test water, and reduce infiltration rate. The average concentrations of Ca and Mg were 78.15 and 16.55 mg L-1. Higher amounts of Ca and Mg ions contributed to the water hardness in some samples. Sodium adsorption ratio (SAR) and the amount of residual sodium carbonate (RSC) ranged from 0.14 to 4.09 and -7.62 to 0.11 meq L-1, respectively, values within the safety limit. Soluble sodium percentage (SSP) ranging from 6.31 to 64.46, graded as excellent to doubtful. The latter category might be unsuitable for crop production and irrigation. The most serious hazard was represented by the contamination with highly soluble Na that could cause a salinity problem in the soil environment and decrease crop yields.