Botany Department, Lucknow University, Lucknow-226007
High alkalinity (S.A.R.) in irrigation waters depressed growth, dry matter production, chlorophyll content and the activity of iron enzymes—catalase and peroxi-dase—in rice plants raised in pot culture. The magnitude of the alkalinity effects being more marked in non-calcareous—low cation exchange capacity—sandy-loam soils than in calcareous sandy-loam or clay-loam soils. Irrespective of alkalinity, high calcium carbonate content in soils also depressed the growth, dry matter production, chlorophyll content and activities of the iron enzymes. High concentration of sodium bicarbonate in irrigation waters largely accounted for the detrimental effects of high S.A.R. on growth and metabolism of rice plants.
