Sodium chloride effects on carbon dioxide exchange rates and other plant and soil variables of ponderosa pine

Abstract

The effects of winter-applied sodium chloride on different plant and soil variables of ponderosa pine (Pinusponderosa Laws) were studied. Potted [Formula: see text]-year-old pine seedlings were treated with sodium chloride foliar sprays and subjected to irrigation treatments at salt concentrations of 0, 3000, 6000, and 9000 mg/L. Sodium chloride irrigations significantly affected the amount of foliar injury, electrical conductivity of the soil, and soil and foliar sodium and chloride levels. All sodium chloride irrigation treatments caused severe foliar injury and almost total mortality during the experiment.Treatments with sodium chloride foliar spray and distilled water irrigations had little effect on soil pH or electrical conductivity, foliar levels of sodium and chloride, and leaf injury or net photosynthesis. However, when plants were grouped according to soil levels of sodium and chloride, it was obvious that those plants having the highest soil sodium and chloride concentrations also had significantly higher injury levels and lower net photosynthesis rates. Soil concentrations of both these ions were too low to cause a decrease in soil solute potential. However, one or both of the sodium or chloride ions could have interfered with nutrient balance, osmotic regulation, or caused some type of specific ion toxicity.