WATER QUALITY ASSESSMENT FOR IRRIGATED AGRICULTURE IN NILPHAMARI DISTRICT

Abstract

An experiment was performed to determine the quality of groundwater for crop production in four Upazilla of Nilphamari district in Bangladesh. One hundred water samples of groundwater and surface water sources were collected from different locations for the determination of chemical quality. The research work was accomplished to assess the extent of water quality and to predict the suitability and acceptability for irrigation, drinking and domestic usage. Surface and groundwater samples collected from selected areas were classified by analyzing chemical constituents present therein. Several parameters like pH, EC, TDS, SAR, SSP, RSC, H, B, Fe, Mn etc were considered for the classification. The pH value of all the water samples fluctuated 6.81 to 7.81 and we found ‘suitable’ for irrigation, drinking and domestic usage. The EC and TDS volume of water samples were found in the range of 284 to 745 uS cm” and 104.5 to 458 mg L"respectively. On the basis of EC and SAR, all the waters were found low salinity and low to medium alkali hazard. Out of the 100 samples, 10 samples were classified as C2S4 and 90 samples were in C3S4 categories. SSP values of 45 samples were rated as excellent, 25 samples were good, 20 samples were permissible and 10 samples were doubtful classes were suitable for crop prediction. Out of 100 samples all samples were suitable for crop production on the basis of RSC values. On the basis of H;, 25 samples were moderately hard, 20 samples were hard and rest samples were very hard categories. TDS values of 10 samples were brackish water and the rest 90 samples were fresh water. The water should not be problematic for irrigation used and also can be safely used for domestic consumption. In the study areas, the water contained an appreciable amount of Ca Mg Na and K in the range of 0.10 to 8.82, 0.71 to 11.64, 1.65 to 7.8 and 0.000769 to 0.03 meq L", respectively. Fe, Mn, Zn, Cu, B, SO, and NO, concentrations were found within safe limit for irrigating crops. Finally the water samples were suitable for crop production. The relationship of water quality factors in computed regression line recorded among the pH-EC, pH-SAR, pH-SSP, and pH-RSP, EC-SAR, EC-SSP, EC-RSC, SAR-SSP, SAR-RSC and SSP-RSC where synergistic; relationship was found. In contrary, pH -EC, pH - SAR, pH - SSP, EC - SAR, EC - SSP and EC- RSC were found an antagonistic behavior. All the waters under test may be recommended for irrigating all types of agricultural crop in the study area. The present investigation indicated that the analysis of groundwater is important for proper understanding of the irrigation and drinking water quality and its impact on crop production and human health. It is suggested that irrigation water should be analyzed systematically for understanding the impact of irrigation water towards the healthy crops in the entire irrigated area through out the country. Some base loving crops can be grown successfully in the area.