Effects of Eucalyptus saligna biochar-amended media on the growth of Acmena smithii, Viola var. hybrida, and Viola × wittrockiana

Abstract

SummaryBiochar has been proposed as a suitable component for growing media; however, little research has been done on the effects of biochar-amended media on ornamental plant growth. We investigated the effects of four rates of application of Eucalyptus saligna wood biochar [0, 2.5, 5.0, or 10.0% (w/w)] in combination with three rates of a controlled-release fertiliser [CRF; 0 (no CRF), 3 kg m-3 (half-rate CRF), or 6 kg m-3 (the recommended rate of CRF)] on the growth of lilly pilly (Acmena smithii), pansy (Viola var. hybrida), and viola (Viola ?? wittrockiana) in a glasshouse experiment. The results showed that dry weight yields increased significantly in all species studied in response to an increase in CRF treatment; however, there was no significant effect of biochar treatment on any species. The combined application of biochar and CRF had significant effects on the concentrations and uptake of different mineral elements by all three species; however, the results were highly variable and no consistent trend was observed. We suggest that the positive responses in nutrient uptake could be attributed to improved fertiliser-use efficiency, as indicated by a higher dry weight yield per unit weight of CRF applied. It is unclear from our results whether E. saligna wood biocharamended growing media could provide nutrients directly to the species studied. Further studies are required to determine whether growing media amended with this biochar are suitable for use in ornamental nursery production.