Interactive effect of different salinity sources and their formulations on plant growth, ionic homeostasis and seed quality of maize

Soil salinity is one of the most pernicious environmental hazards affecting crop growth and productivity in arid and semi-arid climates. In saline soils, the crop plants encounter nutrients deficient conditions mainly due to antagonistic affinity of sodium (Na⁺) and chloride (Cl^-). The accumulation of salts in the rhizosphere restricts plant growth, the severity of which depends on the source and concentration of the salt. Therefore, we hypothesized that sodium containing salts could have toxic effects on maize plants either in a single or in combined form. To evaluate the interactive effect of sodium salts on plant growth, ionic homeostasis, and seed quality attributes, a pot study was performed using maize as a test plant at the research area of the College of Agriculture, University of Sargodha. Selected salts including, NaCl, Na₂SO₄ and their combination (NaCl + Na₂SO₄), were applied in equal ratio for different salinity levels (7, 10, 13 and 16 dS m^-1) and the untreated control. The results show that all the measured growth, yield, biochemical and quality attributes of maize were negatively affected with increasing concentration of all the salt sources; however, severity of these effects were more intense when NaCl was applied at all salinity levels. It is concluded that all salts (NaCl, Na₂SO₄ and NaCl + Na₂SO₄) had negative effects on biochemical, qualitative, growth and yield characteristics of maize plant. Most importantly, NaCl was found to be more harmful compared to Na₂SO₄ and mixtures of both salts due to the dominance of Na+ and Cl^-ions. Among all salinity levels, the more detrimental effects of NaCl occurred at salinity level of 16 dS m^-1.