Abstract
Soil salinity is a major threat to the sustainability of agricultural production systems and has defeated civilisations whenever the cost of remediation exceeded the benefits. Among the reasons for this is the complexity of the plant-water-soil nexus and that the causes of salinity are often separated from the damage in time and space. There have been many activities to address salinity, and while good progress has occurred in commercially attractive irrigation areas, many apparently successful techniques, such as intercropping obligate halophytes with conventional crops, processing halophyte meals for human consumption and new uses for saline waters, have not been taken up, although the benefit in ecological terms is understood. There are limited payments available for some ecosystem services, but these are not yet a very recognised market for land users, whose agency is essential for long term success and addressing this requires institutional evolution. We conclude, from Australian experience, that a more concerted effort, perhaps initiated by a philanthropist, is needed to show merchants and agencies how a range of payments for ecosystem services can be turned into true markets in an aggregate way so the ‘knowledge of what can be done can be transformed into benefit’.
Highlights
Coevolution of plants and animals, including humans, has produced a situation where 7.8 billion people are sustained by agricultural production based on soils and water favourable to high net primary production (NPP)
This is often not considered in programs to address salinity at its source even though the damage to ancillary installations and equipment in many situations may exceed that to agriculture per se
Western Australia is most affected by salinity in Australia, with around 70% of arable land suffering from land salinisation
Summary
Coevolution of plants and animals, including humans, has produced a situation where 7.8 billion people are sustained by agricultural production based on soils and water favourable to high net primary production (NPP). Over the last 50 years, per capita availability of arable land has decreased by about two-fold, due to increasing rates of urbanisation and land degradation caused by various environmental constraints [5], pushing agriculture into marginal lands In most cases, such lands could be made productive only by irrigation. Salinity is but one form of damage to the natural resource base being carried by water, its damage is insidious and incurred by associated infrastructure This is often not considered in programs to address salinity at its source even though the damage to ancillary installations and equipment in many situations may exceed that to agriculture per se. Best available estimates in 2000 showed that about 5.7 million hectares of land were within regions identified as being at risk of or affected by dryland salinity
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