Nutritional constraints to growth of Australian red cedar (Toona ciliata) seedlings in five north Queensland soils

Summary

Landscapes that are candidates for rehabilitation with tree species often include soils that are infertile, either inherently or as a result of previous agricultural, logging or mining activities. The potential nutritional constraints to the establishment of high-value cabinet timber species on five such north Queensland soils were evaluated in glasshouse nutrient omission experiments with seedlings of Australian red cedar (Toona ciliata M. Roemer). The soils, collected from sites now considered marginal or uneconomic for agricultural production but which had formerly supported tropical rainforest, were broadly representative of those available for plantation or agroforestry development in the region and differed in both parent materials and previous land-use histories. Within each soil there were marked differences in seedling dry matter production associated with the range of nutrient omission treatments that were imposed. Depending on the soil, single and multiple nutrient deficiencies were identified: phosphorus in a metamorphic soil from South Johnstone (Galmara series); nitrogen in a basaltic soil from Atherton (Pin Gin series); nitrogen and sulphur in a granitic soil from Feluga (Thorpe series); nitrogen, phosphorus, potassium, and sulphur in a basaltic soil from Innisfail (Eubenangee series); and phosphorus, potassium, and calcium, and possibly nitrogen and sulphur in an alluvial soil from Jarra Creek (Virgil series). This study demonstrates that there are potentially major nutritional constraints to the establishment and survival of tree species on many soils in north Queensland.