Ion Uptake in Tall Fescue as Affected by Carbonate, Chloride, and Sulfate Salinity

Abstract

Turfgrass nutrient uptake may be differentially affected by different salts. The objective of this study was to compare nutrient uptake in tall fescue ( Festuca arundinacea Schreb.) as affected by carbonate, chloride, and sulfate under iso-osmotic, iso-Na ⁺ strength conditions. ‘Tar Heel II’ and ‘Wolfpack’ cultivars were subjected to NaCl, Na ₂CO ₃, Na ₂SO ₄, CaCl ₂, NaCl+ CaCl ₂, Na ₂CO ₃+ CaCl ₂, and Na ₂SO ₄+ CaCl ₂, in the range of 0 to 225 mM. There was no cultivar difference regarding K, Na, Mg, and Mn content in shoots. ‘Tar Heel II’ had higher shoot Ca content than ‘Wolfpack’, which were 6.9 and 5.7 g kg ⁻¹, respectively. In general, K ⁺/Na ⁺ ratio decreased with increasing salt concentrations, which reached <1 at about 87.5 mM in Na ₂CO ₃ treatment. All salt treatments decreased Mg content in shoot tissues, especially in Na ₂CO ₃ and treatments containing CaCl ₂. Both Ca and Mg content in shoot were higher in the NaCl treatment than the Na ₂SO ₄ and Na ₂CO ₃ treatments. All salt treatments except Na ₂CO ₃ had higher Mn content in shoots compared to the control. In conclusion, nutrient uptake was differently affected by carbonate, chloride, and sulfate which are different in pH, electrical conductivity (EC), and osmotic potential at the same concentration. Adding Ca to the sodium salts increased Ca content and balanced K ⁺/Na ⁺ in shoots, but did not increase Mg content, which was below sufficient level. Maintaining Mg content in shoots under salinity stress was recommended. The physiological impact of elevated Mn content in shoot under salinity stress requires further study.