The role of common iceplant (Mesembryanthemum crystallinum) in the deterioration of medic pastures

The presence of residues of iceplant (Mesembryanthemum crystallinum) was found to significantly decrease the production of a volunteer annual pasture in subsequent years. Iceplant gathers salt from throughout the root zone of even a slightly saline soil and accumulates it in the aerial parts of the plant. Following senescence, rain leaches the salt onto the soil surface, which becomes so saline as to inhibit the growth of most competing species, and of iceplant itself. It is suggested that as the salt is leached from the top soil, iceplant can dominate by being able to establish at higher levels of soil salinity than potential competitors. The accumulation of salt in iceplant is not primarily a halophytic mechanism but a competitive strategy, allowing it to be a facultative halophyte.