Post-outplanting growth of containerized seedlings of Cryptomeria japonica and Chamaecyparis obtusa in growth media containing wood ash

Abstract

Power generation using wood biomass has become popular as a renewable source of energy; however, the disposal of large amounts of combustion ash generated on account of it has become problematic, especially with the increasing operation of large power plants. Wood biomass ash contains nutrients, such as potassium and calcium; therefore, it may be used as a fertilizer in the growth medium of containerized seedlings. This may allow us to effectively utilize wood ash and also reduce the cost of growing seedlings. Hence, the influence of wood ash containing media on the growth of seedlings should be clarified not only in the container but also after planting. After outplanting containerized seedlings of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa) in wood ash containing media with different wood ash mixing rates into the nursery, the growth of sugi seedlings in 5% and 10% mixing rates was observed to be similar to that in 0% mixing rate. The development of sugi seedlings in 25% mixing rate was significantly lower than that in 0%, 5%, and 10% mixing rates; however, it caught up with that of the other ones after three years. The growth of hinoki seedlings in 5% mixing rate was similar to that in 0% mixing rate. The mortality of hinoki seedlings in 10% and 25% mixing rates was high, whereas the growth of a few seedlings was the same as that in 0% mixing rate. Although the limit of wood ash mixing rate in the containerized seedling medium differed between sugi and hinoki, the growth of seedlings after outplanting could be ensured if the mixing rate was within the limit.