Some physiological effects of high sodium, calcium and chloride concentrations on cotton

Abstract

This investigation was conducted to determine the effect of substrate concentrations of NaCl and/or CaCl₂ on cotton (Gossypium hirsutum L. Deltapine 16) growth, yield and tissue ionic balance. An attempt was made to study a possible Ca-Na interaction on the physiological and growth effects of salinity. A considerable amount of seemingly conflicting and confusing data exist on the detrimental effect of salinity growth, yield and ionic balance in several crops. Little data is available on the effect of Ca in offsetting detrimental effects of high substrate Na levels. Cotton plants were grown in the greenhouse in sand and irrigated with modified Hoagland's solution salinized with NaCl at 0, 10 and 100 me/l in combination with CaCl₂ at 1, 10, 20 and 100 me/l. Dry weight of the plant tissues and plant height were determined at two harvest dates (50 and 90 days) and used as indicators of salinity effects on growth and yield. Tissue ion levels were determined by flame spectroscopy (Na, K), atomic absorption spectroscopy (Ca, Mg) and specific ion electrodes (Cl NO₃). A nitrogen analyzer was used to determine total N levels of leaf tissue. In general, each increase in substrate NaCl concentration caused decreased growth and yield. The addition of only CaCl₂ to the substrate solution caised an effect on growth and yield only at the 100 me/l concentration in which a decrease in both parameters was observed due to the high salt level..