Determination of salinity tolerance in some warm season turfgrass cultivars and assesment of the results for landscaping practice

This study was carried out to determine the salinity tolerance of various warm season turfgrass cultivars (Cynodon dactylon 'Del Sol', Zoysia japonica 'Zenith', Paspalum vaginatum 'Seasprey' and Eremochloa ophiuroides 'Tifblair') by using irrigation waters with different salinity levels. The study was conducted under open sided, plastic film coated greenhouse conditions, planting cultivars in plastic pots (7 L) filled with a mixture of soil, sand, and peat (4:1:1 by volume) as a growing substrate. Six different irrigation water sources with gradually increased salinity levels [0.54 (T0, control; well water EC value), 5 (T1), 10 (T2), 20 (T3), 40 (T4) ve 60 (T5) dS.m-1] were applied to turfgrass cultivars. During the experiment, observations and measurements were made on the leaf firing, turf quality, clipping yield, shoot and root dry weights, leaf width and length. Salt tolerance and threshold value of cultivars were also calculated. In addition, leaf nutrient contents of cultivars under different salinity levels were determined. The results indicated that the increased salinity level of irrigation water negatively affected all parameters except the root dry weight. In terms of turf quality and leaf firing, P. vaginatum 'Seasprey' was the most salt tolerant, whereas C. dactylon 'Del Sol' and Z. japonica 'Zenith' showed moderate tolerance and E. ophiuroides 'Tifblair' was the least tolerant warm season turfgrass cultivars. Salinity threshold values were calculated as 11.4 dS.m-1 for C. dactylon 'Del Sol', 8.9dS.m-1 for Z. japonica 'Zenith' and 5 dS.m-1 for P. vaginatum 'Seasprey'. E. ophiuroides 'Tifblair' could not develop any tolerance against salinity. Salinity levels in irrigation water at 40 and 60 dS.m-1 resulted in complete plant death of all cultivars. However, the earliest plant losses were recorded in E. ophiuroides 'Tifblair' at a 20 dS.m-1 salinity level at 6 weeks after application. Results also indicated that increased salinity levels resulted in significant decreases in N, P, K contents and increases in Ca, Mg, Fe and Na contents of the leaves. In addition, the results of the experiment were assessed for landscaping practice.