Suitability assessment of groundwater quality for irrigational use in Sagardighi block, Murshidabad district, West Bengal

Groundwater alone comprises nearly about 80% of the available water for irrigation purpose in Murshidabad and this usage of groundwater for irrigation is yet to increase further in the upcoming years. The present study was carried out to access the groundwater's suitability for different agricultural purposes in and around Sagardighi block of Murshidabad district, West Bengal, India. Groundwater samples from thirty three different locations around Sagardighi were collected and then tested in the laboratory for various physical as well as chemical parameters such as electrical conductivity (EC), total dissolved solids (TDS), pH, some major cations (Ca2+, Mg2+, Na+, K+, Fe2+) and some anions (CO32-, HCO3-, Cl-). To further delineate the suitable groundwater zones for irrigation practices, the irrigation water quality parameters such as sodium adsorption ratio (SAR), sodium percentage (Na%), magnesium adsorption ratio (MAR), permeability index (PI), residual sodium carbonate (RSC), Kelly's ratio (KR) were also calculated. Results show that most of the water samples had low to medium salinity, while only a very few of the samples show high salinity. Piper trilinear plot reveals that the water is primarily of Ca-Mg-HCO3- facies type. The SAR value of majority of the water samples in the study area are less than 10, which is within safe limits. RSC values indicate that the carbonate content is extremely low in the groundwater of the study area. Overall, the results indicate that majority of the samples are fit to be used for irrigational purpose. The findings of this study would help decision-makers in developing irrigation suitability planning and groundwater resource management in the future.