Monday, November 5, 2007
75-4

Understanding Salt and Water Dynamics to Enhance the Quality of Turfgrasses Irrigated with Saline Water in a Mediterranean Environment: An Evaluation of Four Species.

Ghazi Abu Rumman, Kirsten Frost, Ed Barrett-Lennard, and Tim Colmer. University of Western Australia, M84 Plant Biology, 35 Stirling Highway, Crawley, WA 6009, AUSTRALIA

Secondary salinity threatens infrastructure and amenity areas in many regions worldwide. We have studied the comparative physiology of salt tolerance in selected species of turfgrass, and the changes in soil salinity, for plots irrigated with fresh or saline water. Four turfgrass species (Paspalum vaginatum, Sporobolus virginicus, Distichlis spicata – three halophytes; and Pennisetum clandestinum – a nonhalophyte) were planted in a randomized complete block design with three replicates. Each plot also housed a weighing lysimeter. Blocks were irrigated with saline (13 dS m-1) groundwater or with fresh water, both at approximately 80% replacement of net evaporation. Soil salinity over time was assessed with the EM38 and by soil sampling. Irrigation with saline water reduced turfgrass colour (i.e. ‘greenness') in Pennisetum, whereas it did not affect colour in Paspalum or Distichlis, and even increased colour in Sporobolus. Under non-saline conditions, water use by Pennisetum and Paspalum was 83% of net evaporation, being higher than Sporobolus (at 74%) and Distichlis (at 63%). Under saline conditions, water use of Pennisetum and Paspalum were both reduced (to 58-63% of net evaporation), whereas it was not affected in Distichlis and even increased slightly in Sporobolus. Data on osmotic and ionic relations in the four species will also be presented. Elucidation of quantitative relationships between growth, water use and root-zone salinity and water content will improve basic knowledge on the functioning of halophytes managed for turfgrass and contribute to the future sustainable management of these species on saline sites.