Investigating the Quality of Groundwater for Agricultural Purposes in Parts of Kerman Province

This research was conducted in order to investigate the quality of groundwater for agricultural use in the northern and central parts of Kerman Province. In this study, there were 534 water samples from 8 counties (Kerman, Zarand, Bam, Bardsir, Jiroft, Baft, Faryab, and Rafsanjan), which were collected from different sources, and concentration of Na+, Ca+2, Mg+2, Cl-, SO4-2, and HCO3-2 was determined. Also, indicators such as Total Dissolved Solids (TDS), Sodium Absorption Ratio (SAR), Permeability Index (PI), Residual Sodium Bicarbonate (RSBC), Electrical Conductivity (EC), Salinity Potential (PS), Magnesium Hazard (MH), Water Hardness (TH), percentage of sodium soluble in water (SSP) were determined and evaluated. After determining the quality characteristics of water, the results were compared and interpreted with water standards for agriculture. AqQA software was used to draw graphs to investigate and compare water characteristics. Based on the results, more than 37% of the studied resources were classified as unsuitable (salinity above 2 dS/m) in terms of salinity. Zarand and Rafsanjan counties had unfavorable conditions in terms of groundwater quality indicators, with EC, SAR, PS, TH, SSP and MH in critical conditions in one or both counties, but, in terms of agricultural water standards, the other sites had good quality water. The combined type of underground water in all areas was Ca-Mg-SO4-Cl: while in the northern parts of the province, such as Rafsanjan, Zarand, Bardsir, as well as Bam and Kerman, the predominant anion of water was chlorine, in Faryab, Baft and Jiroft, the status of the predominant anions was slightly sulfate. In most of the counties, Na+>Mg+2>Ca+2 were the dominant anions of chlorine-waters, and little bicarbonate was observed. Also, the dominant water in all areas were Na-Cl and Mg-Cl . Therefore, it is necessary to manage water properly and plant crops suitable for the chemical conditions of waters.