Macadamia biochar as a growth stimulus for Eucalyptus nitens forestry nurseries

The use of Biochar as a potting mix amendment to reduce fertiliser rates and aid the growth of Eucalyptus nitens seedlings grown for Tasmanian commercial forest plantations was investigated. The early growth of E. nitens seedlings (from seed to nine-month-old seedling) was analysed under controlled conditions (glasshouse) in a pot trial. The treatments combined two fertilizer levels (100% and 50% of the commercial rate) with eight biochar doses (0, 2, 5, 10, 20, 50, 80 and 100 t/ha). Seedling height was measured weekly during the experiment, while agronomic response data was collected at four destructive harvesting periods at 135, 177, 219 and 268 days after planting. The results of the agronomic response (height, biomass) showed a strong dependence on fertilizer level but no significant differences in reference to biochar levels. Biochar was found to influence the level of water content in leaves and soil.