NUTRIENT CONCENTRATIONS OF FOLIAGE AND SOIL IN SOUTH-WESTERN AUSTRALIA

The element found in highest concentration in the shoots of the South-western Australian plants surveyed is N followed by K > Ca > Cl > Mg > P > Mn > Zn > Cu. Tle oligotrophic families (mainly primitive Australian pioneer families Proteaceae, Casuarinaceae, Restionaceae and Epacridaceae) have the lowest nutrient concentrations. The nitrogen-fixing Mimosaceae and Papilionaceae have the highest N concentrations though the nitrogen-fixing Casaurinaceae have relatively low N concentrations. The native shrubs have lower tissue concentrations than the introduced species. Certain families possess a great variation in the concentration of tissue Mn (e.g. Proteaceae, Casuarinaceae) with certain individuals containing high concentrations compared to the average South-west Australian species. Increased amounts of soil nutrients can cause an increase in shoot concentration of the species found growing there, e.g. rich habitats (limestone heath) tend to have higher concentrations than those found on depleted habitats (sandplain heaths). There was no correlation found between shoot concentrations and mean annual rainfall.