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: email@example.com 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 run-off. 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: firstname.lastname@example.org focus ON PERENNIALS 3
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