APPRAISAL OF QUALITY OF IRRIGATION WATER OF CANNING BLOCKS OF WEST-BENGAL

Irrigation water samples (92 and 79) collected from various sources of Canning (I and II blocks respectively) during 1991-94 were classified on the basis of electrical conductivity (EC) and sodium adsorption ra tio (SAR). There was good rise in salinity and Na+, Mg2+, Ca2+, Cl- an d B concentrations of irrigation waters, with change in the time of co llection from December-January to April-May. Water of each class stron gly influenced the salinity of the irrigated soils except class I wate r having EC less than or equal to 1.0 dS/m and SAR < 10 (m mol/litre)( 1/2). Using the threshold salt concentration limit of less than or equ al to 1 to 1.3 mg/litre (EC less than or equal to 1.5-2.3 dS/m) of wat ers and its influences on corresponding soils, 77 and 47% water in Can ning I and II blocks, respectively were found suitable for irrigation in December-January and; 35 and 25% in April-May.