Evaluating the suitability of shallow aquifer for irrigational purposes in some parts of Kelantan, Malaysia

Groundwater is a precious natural resource for the people of Kelantan, Malaysia, as it constitutes the main source of water supply. It serves as the most reliable source of water for their domestic and agricultural activities. This study was aimed at assessing the suitability of groundwater for irrigational purposes in some selected communities of Kelantan where farming activities are very intensive. Thirty-two (29 groundwater and 3 surface water) samples were collected and analysed for major anions and cations. Physicochemical parameters such as electrical conductivity (EC) and total dissolved solids (TDS) were also measured. From the results of the analyses and measurements, the suitability of the groundwater for irrigation were evaluated based on the TDS, EC, percentage sodium (%Na), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), Boron classification, fluoride and Nitrate. US salinity laboratory (USSL) diagram and distribution maps of different parameters were also applied in the present investigation. SAR plot indicates that the groundwater falls within the excellent class for irrigation. In terms of sodium percentage, most of the samples fall within the doubtful class with few samples in permissible class. With respect to residual sodium carbonate, majority of the samples exhibit doubtful class with only few samples in permissible limit. Other samples recorded are not suitable for irrigation. Based on the boron classification, the samples fall within the excellent water class. The groundwater in the study area is generally good for irrigation purposes. However, there are few instances which are problematic and would require special irrigation methods