Restoration of saline land through revegetation

In southern Australia. the replacement of deep-rooted perennial native vegetation with shallow-rooted annual crops has resulted in a rising water table and the development of a major secondary salinity problem. It is now acknowledged that the restoration of landscapes will require the reintegration of perennial plants (trees, shrubs and fodders) back into farming systems. Notwithstanding this, in many regions, salinisation processes will continue because the available perennial options are less profitable than annual cropping. This review therefore focuses on a less holistic approach, namely. the partial restoration of productivity of saltland through revegetation with salt tolerant plants (halophytes). Three major stresses affect plant growth on saltland: salinity, water logging and inundation. Although halophytes can accumulate quite high concentrations of salt in their shoots, it is argued that the use of the halophytes to lower salt concentrations in most saline soils would be slow (at best). However, data are available to show that stands of halophytes can transpire sufficient water to lower watertables, thereby ameliorating water logging (and presumably inundation). One consequence of the use of groundwater by salt tolerant perennial plants is the accumulation of salt in the rootzone. This has the potential to be highly damaging to plant growth and survival in the longer-term. (C) 2002 Elsevier Science B.V. All rights reserved.