Salt Effects on Seedling Growth and Ion Uptake of Three Pecan Rootstock Cultivars1

Abstract

AbstractSalt damage is often reported in irrigated cultivation of pecans (Carya illinoensis K.), yet little is known about the concentration or the salt element present in soils, which causes the damage. This study was conducted to evaluate the effects of salinity, Na and Cl on growth and ion uptake of pecan seedlings used as rootstock. The seedlings of three cultivars (‘Apache’, ‘Burkett’, and ‘Riverside’) were grown for 2 years in outdoor lysimeters containing fine loamy sand (calcareous, mixed, thermic, Typic Torripsaments). They were irrigated with eight different qualities of water; four of which had salinity levels of 0.8, 2.1, 3.4, and 6.2 dS m−1 and the additional four containing greater proportions of Na, Cl, or CaSO4. Seedling growth evaluated in terms of leaf, stem, and root weights was inversely related to Na concentrations in soil solutions as well as Na contents of seedling leaves with r values generally exceeding 0.90. The concentrations of Na in soil solutions corresponding to 25% reduction in seedling growth were approximately 40 mmol L−1 for Apache and Burkett, and 50 mmol L−1 for Riverside. Leaf Cl contents correlated neither with Cl concentrations in the soil solutions nor with seedling growth. Seedlings of Riverside absorbed substantially lesser amounts of Na and produced equal or greater root mass, and may be better suited as rootstock in saline areas.