Abstract
Most of the combustion ash produced from the woody biomass power plant has been considered as industrial waste. However, ash contains nutrients such as Ca and K and may be reusable as a fertilizer and/or soil material for cultivating seedlings. To evaluate the feasibility of using ash as container growing media, we measured the growth and nutrient status of Sugi (Cryptomeria japonica) and Hinoki (Chamaecyparis obtusa) seedlings planted in containers with different mixing ratios of 0% (as a control), 5%, 10% or 25% of ash application (by volume). Ash application did not increase the seedling size of both Sugi and Hinoki. The height, diameter, and biomass growth of Sugi treated with 25% ash application were significantly restricted compared with those of other treatments. In Hinoki, the height, diameter, and biomass growth were significantly restricted with 10% and 25% ash application. The exchangeable Mg and Na contents in the growing media at the end of the growing season were lower in the seedlings treated with a higher ash mixing ratio. Needle Ca content of Sugi was increased with a higher ash mixing ratio, whereas that of Hinoki was comparable among treatments. No significant difference was observed in needle Mg and K contents of both Sugi and Hinoki among treatments. These results suggested that ash could be mixed up to 10% and 5% for Sugi and Hinoki, respectively, into container growing media without restricting seedling growth. It would be necessary to investigate whether ash-mixed seedlings grow well after planting in a forest.
