2017 NO.1
Optimizing the growth and N status of containerized Australian Blackwood (Acacia melanoxylon) seedlings with exponential nitrogen loading
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| Optimizing the growth and N status of containerized Australian Blackwood (Acacia melanoxylon) seedlings with exponential nitrogen loading | ||
| Ding Xiaogang | ||
| Guangdong Academy of Forestry, | ||
| Abstract: | ||
| Exponential nitrogen (N) loading approach has been used to optimize seedling growth in container seedling production. However, the response of seedling growth to N loading and optimal N loading rates are species-dependent. There is a lack of information on optimal N loading in container production of Australian Blackwood (Acacia melanoxylon) seedlings. In this study, 7 exponential N loading at rates of 0, 50, 100, 200, 300, 400, and 600 mg N seedling-1, respectively, were applied at the week 3, 6, 9, 12 and 14 after transplanting to determine optimal loading approach based on seedling height, root collar diameter (RCD), biomass accumulation and N uptake in tissue-cultured Australian Blackwood (A. melanoxylon) seedlings. Seedlings did not respond to N loading 3 wk after transplanting, then the accumulative addition of N loading for improved RCD and seedling height was 12.99 and 28.02 mg N seedlings-1 in the 100 N and 400 N treatment 6 wk after transplanting, respectively, and on 9 and 12 wk, that for improved seedling growth was 63.64 and 400 mg N seedling-1 in the 200 N and 400 N treatment, respectively. Vector diagnosis of final biomass and N status indicated that the dose of 100 and 400 mg N seedling-1 was characterized to be "deficient" and "optimum" dose of exponential N loading for Blackwood seedlings. These conclusions promise to figure out a precise fertilization regime for Blackwood seedlings and the demonstration of dynamic seedling performance could be used for other tree species | ||
| Key words: Australian Blackwood · Exponential N loading · Growth performance · Luxury N consumption · Vector diagnosis |