In today's mature water economy it is much less likely that large new dams will be built at public expense for irrigation. However, the practice continues of selling water under historically determined non-transferable quotas at prices well below its cost and its productive value. This perpetuates uneconomic allocation of irrigation water, and tends to add to salinity problems.[59]

3 In many respects Australia is a difficult country to farm. Many pioneers had to convert native forests to pastures and arable land. Water supplies had to be conserved and distributed. The point has now been reached where some plants and animals are grown intensively under controlled environments.

Substantial resources have also been invested since 1947 in attempts by CSIRO to develop techniques of rain-making by the use of fine particle sprays (silver iodide smoke) to induce clouds, particularly cumulus formations in temperate areas, to precipitate their moisture. The results have not, however, yielded consistent and reliable evidence that rainfall can be significantly increased, particularly in the drought affected regions which need it most, and, in any case, the high costs of application have made the technique unattractive.

On the other hand, research on the use of mono-molecular surface films to cover dams and water storages has led to some practical methods of reducing evaporation losses by up to 50 per cent under certain conditions. Because of its national importance a great deal of research continues to be undertaken on problems of water collection, storage and use, and on techniques of irrigation and drainage. In most cases these issues involve difficult technological problems combined with equally complex economic considerations and, although progress is being made, setbacks and disappointments continue to occur.

Trace element research

By contrast, a series of improvements to the environment which were badly needed, universally welcomed and yielded outstanding economic returns were those associated with the provision of certain trace elements to the soils of many localities throughout temperate Australia.

The nutrients in Australia's very old and eroded soils had been badly leached and, although the relatively sparse native vegetation was adapted to these conditions the introduced crops and pastures were not. It was G. Samuel and C. S. Piper who, in 1929, recorded the first trace element deficiency, that of manganese in the black soils on which oats were being grown near Mount Gambier in South Australia.[60]

From the mid-thirties onwards trace elements progressively came to be regarded in Australia as fertilizers in the hands of agronomists, permitting successful crops and pasture production, where previously such pastures and crops could not be grown.[61]

Australian Academy of Technological Sciences and Engineering