EFFECT OF SODIUM TO CALCIUM ACTIVITY RATIO AND RESIDUAL SODIUM-CARBONATE IN IRRIGATION WATER ON PHYSICOCHEMICAL PROPERTIES OF THE HAPLUSTALFS AND PERFORMANCE OF WHEAT (TRITICUM-AESTIVUM L)

Two texturally different, fine loamy (clay loam) and coarse loamy (sandy loam) mixed hyperthermic Haplustalfs were irrigated with waters of varying quality, prepared artificially using different levels of SCAR (Sodium to calcium activity ratio) and RSC (Residual sodium carbonate) to raise the wheat crop. The magnitude of change in physico-chemical properties is not identical at equivalent level of RSC in irrigation water. Increasing levels of SCAR from 7 to 10 and RSC from 0 to 10 me L-1 in irrigation water decreased the electrical conductivity, hydraulic conductivity, water holding capacity and contents of organic carbon, soluble cations and anions and increased the pH and ESP of the soil. The effect on morphological characters, dry matter yield and uptake of nutrient varied with Mg.Ca ratio in irrigation water and clay content of the soil. The reduction in plant growth, dry matter yield and nutrient uptake was more pronounced at SCAR value of 10 in irrigation water and in soil finer in texture, indicating SCAR to be a better ind'' for judging the suitability of irrigation water than that of SAR.