ABSTRACT
Nitrogen (N) absorption is inhibited by root zone salinity, which could result in increased NO3 leaching. Conversely, N absorption is enhanced by moderate N deficiency. Because turfgrasses are grown under N-limiting conditions, it is important to understand the interactive effects of salinity and N deficiency on N uptake. This study examined the effect of N status (replete versus deficient) and salinity on N (15NO3 and 15 NH4) uptake and partitioning by tall fescue (Festuca arundinacea Schreb.). 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, and 120 meq L−1) in a factorial arrangement. Absorption of NO3 and NH4 was greater in low-N than in high-N cultures, but was reduced by salinity under both N treatments. Salinity reduced partitioning of absorbed N to leaves and increased retention in roots. These results suggest that turfgrass managers should consider irrigation water quality when developing their fertilizer program.
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Notes
∗,
∗∗,
∗∗∗ Significant at P = 0.01, 0.001, respectively.
∗,
∗∗,
∗∗∗ not significant, significant at P = 0.05, 0.01, and 0.001, respectively.