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ffi CrC research Director


ffi CrC research Director

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									Myth busting — critical
for smart investment
 f      fi CrC research Director
        Dr mike ewing (pictured right)
        has called for researchers to
either uphold or ‘bust’ current salinity
                                                    By Jill Griffiths
                                                    Kondinin group

management myths by focusing on
where the greatest economic benefits             are needed, selection and development of          “While substantial resources are currently
can be made.                                     some existing crop species for improved           being directed towards understanding salt
                                                 salinity tolerance presents a clear alternative   tolerance at gene level, with some success,
speaking at the 2nd international salinity       to domestication of halophytes.                   it is not a given that associated genetic
forum, Dr ewing said that when focusing                                                            engineering will lead to substantial or rapid
attention in the landscape it was important      there is also a need to look beyond salt-         improvements in performance of major field
not to tackle the worst areas first; economic    tolerant shrubs, as they did not necessarily      crops when grown in saline environments,”
benefits were generally best maximised by        offer the best prospects for forage innovation    Dr ewing said.
intervening on less salinity-impacted areas.     and livestock production.
                                                                                                   “research has shown tolerance to salinity is
“We should not confuse economic and              “legumes represent a priority opportunity for     physiologically and genetically complex, so
aesthetic benefits,” Dr Ewing said.              saline pasture innovation based on their high     comprehensive tolerance is unlikely to be
                                                 grazing value for livestock, enhancement of       delivered by a single gene. in this setting,
Dr ewing said it was a myth to think plants      companion species, cost savings in fertiliser     genetic engineering is challenging.
on saline land always had low inherent           nitrogen, and under-exploited genetic
                                                                                                   “the observed complexity of salinity
productivity and that scarce resources should    variation,” Dr ewing said.
                                                                                                   tolerance reduces the likelihood that this
be directed towards improving productivity
                                                                                                   knowledge will rapidly translate into useful
and income on non-saline land. rather, some      Molecular technologies take time                  transgenic cultivars.”
saline land justified investment in production
                                                 researchers and farmers alike have high
and research.
                                                 expectations around the ability of molecular           More information
                                                 technologies in delivering us quick and easy
Looking beyond halophytes                                                                          ffi CrC research Director, Dr mike ewing
                                                 solutions needed for change. The difficulties
another perpetuated myth is that saline          involved in using molecular technologies          T: (08) 6488 1876
agriculture depends entirely on the discovery    to produce plants with useful field salt
of new halophytes (extremely salt-tolerant       tolerance restricts their potential to become
                                                                                                   M: 0409 116 750
species). although new salt-tolerant plants      short- and medium-term solution providers.        E:

Do trees really work to tackle salinity?
 p    lanting trees on cleared
      agricultural land to lower
water tables and reduce salinity
                                                 george. for the study, trials were established
                                                 on 15 farms in south-western australia
                                                 between 1990 and 1996. the trials featured a
                                                                                                   revegetation is undertaken, but these benefits
                                                                                                   may be countered by reduced freshwater
has been promoted since the                      variety of tree-planting configurations, mostly
mid-1980s.                                                                                         the research also found that the level of
                                                 within upland catchments with the planted         revegetation required to provide significant
However, research by hydrologists from the       areas covering over 98% to less than 5% of the    salinity benefits at a farm-scale was unlikely
Department of agriculture and food, Western      landscape.                                        to be attractive to ‘mainstream farmers’,
australia (DafWa) shows that in some systems     the effect of the vegetation on the               unless there was income derived from the
this may not hold true.                                                                            revegetation.
                                                 water table was calculated from regular
research published by DafWa hydrologists         measurements made from 226 piezometers            even so, Dr george said it was still important
during 1999 concluded that trees were best       and observation bore holes.                       to plant trees.
planted in recharge areas, as discharge
                                                 research results concluded that the               “there is still a valid set of reasons to plant
plantings rarely reclaimed saline areas and
                                                 proportion of vegetation was the most             trees, but the original goals of salinity
water table responses were generally confined
                                                 significant factor influencing the water table    management have not been realised. our
to beneath the tree plantings. extensive
                                                 — the larger the area planted, regardless of      expectations in that regard were probably too
planting (up to 80 per cent of the landscape)
                                                 configuration, the greater the reduction in       high.”
was needed to significantly reduce the area
of salinity.                                     water table.
                                                                                                        More information
recent work supports this earlier research,      areas of less than 50% of plantings were
such as the recent study presented at the        unlikely to measurably reduce salinity at         Don bennett, DafWa
2nd international salinity forum by DafWa        the farm scale. some catchment-scale              T: (08) 9780 6298
hydrologists Don bennett and Dr richard          salinity benefits may occur when moderate         E:

                                                                                                        focus        ON PERENNIALS

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