Water Relations and Drought Tolerance of Four Turfgrasses

Abstract

Greenhouse studies were conducted on three warm-season turfgrasses, `Midlawn' bermudagrass [ Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy], `Prairie' buffalograss [ Buchloe dactyloides (Nutt.) Engelm.], and `Meyer' zoysiagrass ( Zoysia japonica Steud.), and a cool-season turfgrass, `Mustang' tall fescue ( Festuca arundinacea Schreb.) to determine 1) water relations and drought tolerance characteristics by subjecting container-grown grasses to drought and 2) potential relationships between osmotic adjustment (OA) and turf recovery after severe drought. Tall fescue was clipped at 6.3 cm once weekly, whereas warm-season grasses were clipped at 4.5 cm twice weekly. The threshold volumetric soil water content (SWC) at which a sharp decline in leaf water potential (ψ L ) occurred was higher for tall fescue than for warm-season grasses. Buffalograss exhibited the lowest and tall fescue exhibited the highest reduction in leaf pressure potential (ψ P ) per unit decline in ψ L during dry down. Ranking of grasses for magnitude of OA was buffalograss (0.84 MPa) = zoysiagrass (0.77 MPa) > bermudagrass (0.60 MPa) > tall fescue (0.34 MPa). Grass coverage 2 weeks after irrigation was resumed was correlated positively with magnitude of OA ( r = 0.66, P < 0.05).