EFFECT OF AMENDMENTS AND SALINE IRRIGATION WATER ON SOIL PROPERTIES AND YIELDS OF RICE AND WHEAT IN A HIGHLY SODIC SOIL

A field experiment at Gudha Experimental Farm, Central Soil Salinity Research Institute, Karnal, India, in 1983/84 evaluated the effect of gypsum (12.5 t/ha, 50 % of gypsum requirement of soil), pyrite (10.2 t/ha, equivalent to gypsum on a sulphur basis), farmyard manure (FYM) (30 t/ha), gypsum + FYM, pyrite + FYM and a control, with saline (EC(iw) 4.0 dS/m) and non-saline (0-4 dS/m) irrigation water on soil properties and yields of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) in a highly sodic soil (pH 10.5, 96% exchangeable sodium). Application of these amendments enhanced the yield of both crops significantly, irrespective of the quality of the irrigation water used. Soil properties and crop yields were improved in the following order: control < FYM < pyrite < gypsum < pyrite + FYM < gypsum + FYM. Irrigation with saline water resulted in significantly higher yields of both crops than irrigation with non-saline water. Decreases in soil pH and exchangeable sodium and increases in exchangeable Ca + Mg and infiltration rate were greater after rice than wheat in the rotation, particularly when non-saline water was used.