Irrigation Water Quality Based on Hydro Chemical Analysis of Ganga-Sone Divide Region of Bihar

The hydro chemical study reveals the quality of water and its suitability for agricultural purpose. Presence of excessive quantities of salts in groundwater is one of the major constrains in agro-well farming in Ganga-Sone Divide. Irrigation with poor quality waters may bring undesirable elements to the soil in excessive quantities affecting its fertility. Electrical conductivity (EC), sodium percentage (Na%), sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) can be used as criteria for finding the suitability of irrigation waters. The objective of this study is to evaluate the suitability of the irrigation water quality of the Ganga-Sone divide region. Major cations, Na⁺, Ca²⁺, Mg²⁺, K⁺ and major anions, Cl, SO₄, HCO₃, CO₃ were determined from 26 observation sites selected by CGWB located in Ganga-Sone divide region to assess the hazards of salinity, sodium and bicarbonate. Out of selected sites, based on EC, 46% of the wells have medium salinity water, 50% of the wells have high salinity water and 4% of the wells have very high salinity water. Based on percent of sodium, 69% of the wells have excellent irrigation water quality, 19% of the wells have good irrigation water quality, 4% of the wells have permissible irrigation water quality, 4% of the wells have doubtful irrigation water quality and 4% of the wells have unsuitable irrigation water quality. Based on SAR, almost all the wells have the good quality of irrigation water. Based on RSC, 100% of the wells have good irrigation water quality.