Evaluating the effect of superabsorbents on soil moisture and physiological characteristics of Lolium perenne L. 'Chadegan' and Festuca arundinacea.

Creating water-conserving turfgrasses using superabsorbents in soil is a challenge especially in arid environments because their related soil and plant’s behavior is still less known. This research investigated soil moisture content and physiological characteristics of Lolium perenne L. ‘Chadegan’ (perennial ryegrass) and Festuca arundinacea (tall fescue), in the absence (control treatment) or presence of four superabsorbent types. The superabsorbents were Zeolite (zero and 10% wt), Bentonite (zero and 6%wt), Aquasorb (zero and 6 g/m2) and Boloorab (zero and 50 g/m2). The experiment was factorial based on a randomized complete block design with four replications. A one-month stop on irrigation occurred after the first five-month full irrigation regime to simulate drought stress conditions. The results showed tall fescue had higher leaf relative water content, lower relative electrolyte leakage and lower relative saturation deficit than that in perennial ryegrass after applying the drought stress. However, tall fescue had higher chlorophyll content than this factor in the ryegrass. Aquasorb and then Bentonite were able to improve the fresh weight and dry weight in roots and shoots under drought stress conditions compared to the control treatment. Using Aquasorb was associated with better physiological characters in the turfgrasses and higher water content in the soil. Overall, under drought stress conditions, planting tall fescue in a soil containing Aquazorb promised a better quality turfgrass for urban green spaces.