Hydrochemical properties of groundwater and land use and land cover changes impact on agricultural productivity: An empirical observation and integrated framework approaches

Land use and land cover (LULC) dynamics of the Bankura district effect groundwater resources and agricultural productivity, particularly the expansion of urban land, discharge of fertiliser mixed water from agriculture and reduction of scrubland. This study investigates the Spatio-temporal relation between groundwater qualities (GWQ), LULC and agricultural productivity of the Bankura district in 2009 and 2020. The twelve standard water qualities parameters; "pH, electrical conductivity (EC), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), iron (Fe3+), bicarbonate (HCO3<overline>), chloride (Cl-), sulfate (SO42-), nitrate (NO3-), and fluoride (F-)" were considered for the study. Landsat-5, 7 and 8 images were classified for 2009 and 2020 to detect LULC dynamics related to GWQ. The results showed that GWQ was depleted in 2020 compared to 2009, with agricultural land suffering from lower GWQ than other land uses. Some of the water quality indices (Mean value of pH, EC, Ca2+, Mg2+, and NO3-) drastically declined in 2020 compared to 2009. The degree of contamination (CD) analysis showed the above value of zero (>CD) is highly vulnerable for dug well users. The mean nitrate (7.281 to 51.387 mg/l), calcium (38.366 to 58.082 mg/l), chloride (121.861 to 125.981 mg/l), and potassium (15.261 to 18.363 mg/l) concentration levels drastically increase over the agricultural land. To know the relationship between LULC and agriculture productivity, block-wise production and yield analysis of both years have been presented. It was seen that there are low crop and high productivity observed from the 2009 to 2015 block of Bankura. The overall result indicates that human activities are the primary cause of spatial-temporal changes in GWQ and agricultural productivity. The geospatial-based water quality assessment benefited in understanding changes in GWQ and developing appropriate site-specific agricultural and health policies.