Effect of Nitrogen Status on Salinity Tolerance of Tall Fescue Turf

ABSTRACT

Turfgrass salinity tolerance is usually studied under conditions of non-limiting nutrition, even though most turfgrasses are managed with growth-limiting levels of nitrogen (N). This study examined the effect of N status (replete versus deficient) on salinity tolerance in tall fescue (Festuca arundinacea Schreb.). Additionally, the interactive effects of N status and salinity on tissue ion concentrations were determined. Two cultivars (‘Monarch’ and ‘Finelawn I’) were grown in nutrient solution culture. Treatments included N level (100% or 25% of maximum N demand) and salinity (0, 40, 80, 120 meq L⁻¹). Salinity reduced leaf growth under high-N conditions, but much less so under low-N conditions. Concentrations of potassium (K), sodium (Na), and chloride (Cl) in the leaf sap were significantly higher in low-N than in high-N plants, indicating that increased salinity tolerance in low-N turf was not due to ion exclusion. These results suggest that efforts to screen turfgrasses for salt tolerance should be conducted using realistic N-fertility levels.

Keywords:

• Nitrogen deficiency
• ion accumulation