摘要
Narail Sadar Upazilla is a major agricultural productive region of Narail District, Bangladesh. The crop production here significantly depends on the Chitra River water for irrigation. The present study was undertaken with an aim to evaluate the usability of this river water for irrigation purpose during pre-monsoon, monsoon and post-monsoon. Sampling was conducted three times in each season both in high tide and low tide. The collected samples were analyzed for some physicochemical parameters including pH, electrical conductivity (EC), total dissolved solid (TDS), major cations (Na+, K+, Ca2+ and Mg2+) and major anions (HCO3?, PO43?, SO42?, Cl? and NO3?). The calculated chemical indices’ values for the collected water samples during pre-monsoon indicate that this river water is chemically suitable for irrigation during pre-monsoon with respect to sodium adsorption ratio (SAR), residual sodium carbonate (RSC) and permeability index (PI). The values of all chemical indices declare this river water fitness for use in irrigation both in monsoon and post-monsoon. According to Wilcox diagram, all of the water samples irrespective of tide and sampling stations fall within “permissible to doubtful” category during pre-monsoon while the water samples collected in both tide from all stations fall within “excellent to good” category during monsoon and post-monsoon. The United States Salinity Laboratory (USSL) diagram certifies this river water as C1-S1 (low salinity along with low sodium level) type during monsoon and post-monsoon which makes the river water suitable for use in irrigation in these two seasons while the water is mostly C3-S1, C3-S2 and C3-S3 (high salinity along with low to high sodium level) type in pre-monsoon which makes the river water restricted for use in irrigation in this season.
Narail Sadar Upazilla is a major agricultural productive region of Narail District, Bangladesh. The crop production here significantly depends on the Chitra River water for irrigation. The present study was undertaken with an aim to evaluate the usability of this river water for irrigation purpose during pre-monsoon, monsoon and post-monsoon. Sampling was conducted three times in each season both in high tide and low tide. The collected samples were analyzed for some physicochemical parameters including pH, electrical conductivity (EC), total dissolved solid (TDS), major cations (Na+, K+, Ca2+ and Mg2+) and major anions (HCO3?, PO43?, SO42?, Cl? and NO3?). The calculated chemical indices’ values for the collected water samples during pre-monsoon indicate that this river water is chemically suitable for irrigation during pre-monsoon with respect to sodium adsorption ratio (SAR), residual sodium carbonate (RSC) and permeability index (PI). The values of all chemical indices declare this river water fitness for use in irrigation both in monsoon and post-monsoon. According to Wilcox diagram, all of the water samples irrespective of tide and sampling stations fall within “permissible to doubtful” category during pre-monsoon while the water samples collected in both tide from all stations fall within “excellent to good” category during monsoon and post-monsoon. The United States Salinity Laboratory (USSL) diagram certifies this river water as C1-S1 (low salinity along with low sodium level) type during monsoon and post-monsoon which makes the river water suitable for use in irrigation in these two seasons while the water is mostly C3-S1, C3-S2 and C3-S3 (high salinity along with low to high sodium level) type in pre-monsoon which makes the river water restricted for use in irrigation in this season.
