Growth and nutrient responses of Betula platyphylla, Larix kaempferi, and Chamaecyparis obtusa to different application methods of solid compound fertilizer

Abstract

We investigated the effects of different placement methods of applying slow-release fertilizer on the growth and foliar nutrients of three contrasting tree species (i.e., fast-growing Betula platyphylla and Larix kaempferi and slow-growing Chamaecyparis obtusa) to provide implications for increasing their growth and survival in marginal forest lands. We applied 84 g pot–1 of solid compound fertilizer (SCF) at different positions: No fertilization (CON), subsurface placement (SCFs), and bottom placement [35-cm depth (SCFb)] in a greenhouse condition. Results revealed that the height and RCD (root collar diameter) of the three species had the highest growth under SCFs. Total biomass across SCFs, SCFb, and CON ordered as follows 130, 72, and 28 g seedling–1 in B. platyphylla, 89, 38, and 27 g seedling–1 in L. kaempferi, and 61, 24, and 23 g seedling–1 in C. obtusa. In contrast, SCFb resulted in the highest root length across the treatments in all species. The root biomass allocation was also higher in SCFb (28%–40%) than that of SCFs (12%–24%). SCFs had higher N uptake in all species than the other treatments. In conclusion, SCFs has shown to be the most effective placement method of SCF application for increasing aboveground biomass and nutrient (N) acquisition, while SCFb was the placement effective for increasing root length and root biomass growth in all species. These results are relevant to the promotion of ecofriendly and cost-effective fertilization approach of increasing growth and survival of economically important forest tree species, especially in steep slope and erosion-prone areas or marginal forest lands.