Evaluation of irrigation water quality for paddy cultivation in Bachok, Kelantan

Abstract

Evaluation of irrigation water quality status was conducted in Bachok district, Kemubu Agriculture Development Authority (KADA) from July 2021 to March 2022. Water quality changes in the irrigation canal were examined by measuring several physical and chemical water quality at eight sampling points. The sampling locations are primary irrigation canals used to supply water into the paddy fields. Water quality parameter measured were temperature, pH, Dissolved Oxygen (DO), Conductivity, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Ammoniacal Nitrogen (AN), Ca, Na and Mg. This paper aims to discuss irrigation water quality status using Water Quality Index (WQI), National Water Quality Standards (NWQS) and Sodium Adsorption Ratio (SAR). The results revealed that water quality were within NWQS Class II-IV except DO, AN and TSS in locations with intensive aquaculture. The average Water Quality Index in all sampling points ranged from 66.67-88.18, indicating that all irrigation water samples falls into the category of excellent and adequate water. The SAR values varied from 1.66-10.20, which means that all irrigation water samples were categorized into suitable for irrigation purposes. This work will help the decision makers to better manage irrigation water resources and policy development for paddy cultivation in KADA.