Effects of the Road Deicing Practices on Gas Exchange Parameters in Urban Lawn Ecosystems

Abstract

More than 1100 million ha of the lands are affected by the soil salinity globally. In Europe, soil salinization affects 1 to 4 million ha and is concentrated mainly in Mediterranean. Among the major causes of salinization in rural areas are salt-water introgression into the ground waters used for irrigation and dust suppression practices, in urban areas - deicing of roads with chloride salts (NaCl, CaCl2). To simulate urban soil salinization after the release of the deicing agents, Lolium perenne, typically used in urban public and private lawns, was planted in pots and grown in the green house for 5 months before being treated with NaCl 0 mM, 30 mM and 90 mM solution as regular irrigation practice. The grass was moved to 4 cm height. Gas exchange measurements: soil respiration, ecosystem respiration and net ecosystem exchange were measured from planted and non-planted collars, installed in the pots. Soil salinization affected negatively soil respiration rates but increased plant respiration proportionally to the level of salinization. Together with the decline in gross primary production, it resulted in no changes in the net ecosystem exchange rates between control and salt treatments. Lolium perenne could be recommended for urban lawns subjected to periodical salinization.