The Effects of Different Irrigation Levels and Nitrogen Doses on Growth, Quality and Physiological Parameters of Warm-season Turfgrasses

This research was conducted to determine to effects of different irrigation levels and nitrogen doses (ND) on the various warm-season turfgrasses at the Agricultural Training and Research Centre of the Bursa Uludag University Faculty of Agriculture for two years in a row. The experimental design was the randomized blocks in a split-split plot design with three replications. The main plot was irrigation levels (I₁=25%, I₂=50%, I₃=75%, and I₄=100% of pan evaporation), subplots were turfgrass species [hybrid Bermudagrass (Cynodon transvaalensis x Cynodon dactylon) cv. Tifdwarf, seashore paspalum (Paspalum vaginatum Sw.) cv. Seaspray, zoysiagrass (Zoysia japonica Steud.) cv. Zenit], and sub subplots were ND’s (monthly 0.0, 1.25, 2.5, and 5.0 g N m^-2). Visual turfgrass color and quality, clipping yield, leaf relative water content (RWC), loss of turgidity (LT), chlorophyll content (CC), and electrolyte leakage were measured. According to the results, significant differences were determined among irrigation levels, turfgrass species, and ND’s for color, quality, clipping yield and physiological parameters. Turfgrass visual color, quality and clipping yield were shown to decrease significantly with decreases in irrigation water and N fertilizer. The study findings demonstrated that under a non-limiting water supply, irrigation could be decreased by adjusting N fertilizer rates with I₃N₃ treatments can maintain acceptable turfgrass visual color and quality under Mediterranean climatic conditions. In addition, at 25% (I₁) deficit irrigation level, leaf RWC, CC decreased significantly, while an increase was determined in LT. This research indicated that under 75% (I₃) deficit irrigation and N₃ ND, acceptable quality can be maintained with ‘seaspray’ seashore paspalum under Mediterranean climate performed.