Assessment of Ground Water Quality for Irrigation in the Farms of Horticultural College and Research Institute, Periyakulam, Theni District

Ground water quality of Horticultural College and Research Institute (HC & RI), Periyakulam located in Theni District, Tamil Nadu was assessed during January 2021. Ground water samples were collected from bore wells and their quality parameters were assessed. pH values ranged from 6.88 to 7.81; electrical conductivity values ranged from 0.20 to 1.28 dSm-1 and most of the samples were under high salinity class (C3) (84.6%). Calcium, magnesium, sodium and potassium content ranged from 1.68 to 4.72 m.e L-1, 0.72 to 10.6 m.e L-1, 1.35 to 10.3 m.e L-1 and 0.05 to 0.23 m.e L-1 respectively. Most of the samples were found to be magnesium dominating and magnesium exceeds the calcium content in most of the water samples. Magnesium toxicity will be exhibited in the continuous use of water to crops. No carbonates were noticed. Bicarbonates, chloride and sulphate concentration varied from 2.0 to 13.4 m.e L-1 , 1.12 to 7.52 m.e L-1 and 0.02 to 0.99 m.e L-1 respectively. The sequence of cations were found in the order of Mg2+ >Na+> Ca2+ >K+ and anions followed the sequence of HCO3- >Cl- > SO42-. Total hardness in the study area varied from 120 to 686 mg L-1 and majority of the samples (61.5 %) were very hard. RSC values varied from -3.76 to 5.24 meL-1 and most of the samples come under the moderate category (61.5%) followed by safe (38.5%). RSBC varied from 0.32 to 9.48 m.e L-1 and majority of the samples come under the safe category (61.5%) followed by unsafe (23.1%) and moderate (15.4%). SAR values ranged from 0.83 to 5.11 and all the samples were found to be low sodium category (S1). There is no sodicity problem existing in the ground waters. In the present study, the permeability index ranged from 39.4 to 80.3 per cent and the majority of the samples come under the permeability hazard class II, which can be used for irrigation without any permeability problem in the soils. As per CSSRI, Karnal classification, majority of the ground water samples coming under good (76.9), followed by marginally alkaline (15.4%) and alkaline (7.7%). Marginally alkaline and alkaline waters should be managed carefully to avoid a negative impacts on soil and crops.