Archives of Agriculture and Environmental Science 5(4): 554-562 (2020) https://doi.org/10.26832/24566632.2020.0504019 This content is available online at AESA Archives of Agriculture and Environmental Science Journal homepage: journals.aesacademy.org/index.php/aaes e-ISSN: 2456-6632 ARTICLE HISTORY ABSTRACT Received: 14 September 2020 Revised received: 18 December 2020 Accepted: 21 December 2020 The main intent of this study was to investigate the condition of groundwater quality for irrigation purposes in and around the main Gadilam river basin, the east coast of southern India. A total of ffty groundwater samples were collected and analyzed for various parameters such as electrical conductivity (EC), pH, TDS, major cations (Ca 2+ , Mg 2+ , Na + , and K + ) and anions (SO 4 2- , Cl - , HCO 3 - , and NO 3 - ). Irrigation water quality parameters like the sodium absorption ratio (SAR), residual sodium carbonate (RSC), percentage sodium (%Na), magnesium hazard (MH), permeability index (PI), and Kelly ratio (KR) were computed to assess the irrigation water quality of groundwater. Furthermore, graphical representation diagrams such as USSL, Wilcox, and Doneen have been prepared for irrigation water quality. From the computation of SAR, Na%, RSC, PI, and KR values, it was found that 100% of groundwater samples were found to be suitable for irrigation purposes. Besides, USSL and Doneen diagrams show that the samples are safe for irrigation usage. The Wilcox diagram in the classifcation of electrical conductivity reveals that most samples fall into the good to permissible class (78%), in doubtful to unsuitable class (20%), and 2% of samples are unsuitable. Magnesium hazards of 82% of the groundwater samples are suitable for irrigation, while the remaining 18% of the samples exceeded the limit and found to be unsuitable for irrigation purposes. The study concludes that higher percentages of groundwater samples were suitable for irrigation purposes in the study area, and the concentration of magnesium infuenced groundwater at a few locations. ©2020 Agriculture and Environmental Science Academy Keywords Groundwater Irrigation water quality Main Gadilam River basin South India Citation of this article: Ravi, R., Aravindan S., Shankar, K. and Balamurugan, P. (2020). Suitability of groundwater quality for irrigation in and around the main Gadilam river basin on the east coast of southern India. Archives of Agriculture and Environmental Science, 5(4): 554-562, https://dx.doi.org/10.26832/24566632.2020.0504019 Suitability of groundwater quality for irrigation in and around the main Gadilam river basin on the east coast of southern India R. Ravi 1 , S. Aravindan 1 , K. Shankar 2* and P. Balamurugan 3 1 Department of Earth Sciences, Annamalai University, Tamil Nadu - 608 002, INDIA 2 Department of Applied Geology, School of Applied Natural Science, Adama Science and Technology University, ETHIOPIA 3 Department of Civil Engineering, M. Kumarasamy College of Engineering, Karur, INDIA * Corresponding author’s E-mail: geoshankar1984@gmail.com INTRODUCTION Water is crucial to life in the world, and knowledge of hydrochem- istry is essential in evaluating the quality of water to understand its appropriateness for a variety of requirements. Groundwater is the most valuable natural resource for human health, ecosystems, and socio-economic growth (Umamageswari et al., 2019). The existence of groundwater is beneficial for a variety of uses (Balamurugan et al., 2020c). Agricultural production could be a key source of economic value, as well as a backbone of the Indian economy. Approximately 70% of India's population is engaged in agricultural activities, either explicitly or implicitly, to provide sustenance (Rawat et al., 2018). It is everyone's responsibility to protect and increase agricultural production to sustain the country's rapidly growing population. Farmers are prone to water pollution, especially in developing countries where rapid industrialization is taking place. Historically, because of its accessibility and cost-effectiveness, farmers rely on surface water irrigation, which is likely to deteriorate due to industrial discharge, resulting in declining crop production and increased ORIGINAL RESEARCH ARTICLE