Residual sodium bicarbonate (RBSC)
Gupta (1983) classified the groundwater for irrigation use based on the
relation between the bicarbonate and calcium ions. The excess
concentration of sodium bicarbonate leads to a harmful effect on soil
(Rahman et al., 2017). In the study area, the RBSC value ranges from
-11.96 to 7.21 meq/L, with an average of -0.05 meq/L (Table.4). About
90% of the sample locations are suitable, and 10% of samples are the
marginal state of contamination (Table.6). The spatial distribution of
RBCS 660.00 sq.km area falls under suitable, and 6.95 sq.km area is a
marginally contaminated type of groundwater (Fig.11e). A higher value of
RBSC indicates the dissolution of organic matter in the soil.