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CSIRO and Bureau of Meteorology 2015 ). This has resulted in dryland salinity
being reclassified from being a major threat to agricultural productivity in the 1990s
to now being a lower-order threat to farm viability. This experience may be relevant
to other dryland agricultural regions with similar Mediterranean and temperate cli-
mates and a history of dryland salinity because of accumulated salts. However, the
drying climate has made the establishment of commercial trees and perennial pas-
tures, common recommended practices for reducing recharge to saline ground
water, more difficult (John et al. 2005 ). The need and cost-effectiveness of surface
and groundwater drains is also reduced because of the lower groundwater levels and
a slower accumulation of salt in topsoils.
9 Conclusions and Future Research Thrusts
Groundwater-induced dryland salinity can appear without prior warning because
groundwater levels are usually not monitored in dryland farming areas. There is also
often a poor understanding of the impact of land clearing on catchment water bal-
ances. Because it can also be associated with sodicity and waterlogging it can be
poorly diagnosed and management responses scan be sub-optimal.
Moreover, a common misconception is that because dryland salinity only affects
2.1 % of dryland agricultural areas world-wide it can be solved with a modest inter-
vention. However, work cited here has shown that it is a symptom of a significant
water imbalance over a larger landscape and solutions need to acknowledge this
scale and long response time-scales. The saline areas are also typically in the most
fertile lower landscape areas and connected to the remaining riverine and related
terrestrial and ecological systems.
The long time-lags are also often unappreciated. The mobilised salt may have
accumulated over hundreds of thousands of years and the hydrological imbalance
may have been going on for decades but was unrecognised. Sometimes the seasonal
or management conditions immediately prior to its emergence may be mistaken as
the primary cause because the long time lag between cause and effect is not appreci-
ated. As a result of these complexities, management interventions are often unsuc-
cessful and money is wasted on solutions that will not deliver the expectations of
funders, not enabling land owners to recover sunk costs. We show that in low-
fertility saline land unable to justify expensive interventions the best response may
be to ‘live with salinity’ and grow crops and pastures with the ability to handle the
conditions. Modifying waterlogging and soil sodicity issues may help these crops
and pastures yield better while operating within the changing hydrologic
conditions.
Dryland salinity is affected by the catchment’s geology, regolith (weathered
material above basement), topography, climate, past water use by plant (which
affects the accumulation of salts) and recent changes to water balances because of
land management practices. Each occurrence therefore has its own unique circum-
D.J. McFarlane et al.