Abstract:
Analyses of rainwater samples from 24 stations in Victoria have shown that with increasing distance from the coast there is a sharp decrease in the influence of the ocean on the nature of the dissolved ions. About 150 miles inland the ionic ratio of sodium to potassium falls below 10, that of sodium to chloride exceeds unity, and calcium becomes the dominant cation. This is considered to reflect the influence of terrestrial material such as the dry surface of soils. As soils also contain sodium and chloride ions, the common assumption that all the chloride in the rain is derived from the ocean is unjustified, hence calculations of the net accession of salt are unwarranted. In southern Australia, sulphate ions are present in much smaller amounts than in other countries and this may contribute to the observed deficiencies of sulphur in plant nutrition. Details are given of the method of collecting the rainwater and of its analysis.