Canadian Forest Service Publications

Premature shoot growth termination allows nutrient loading of seedlings with an indeterminate growth strategy. 2013. Schott, K.M.; Pinno, B.P.; Landhäusser, S.M. New Forests 44(5):635-647.

Year: 2013

Issued by: Northern Forestry Centre

Catalog ID: 34841

Language: English

Availability: Order paper copy (free), PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1007/s11056-013-9373-9

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Nutrient loading of nursery seedling stock of species with an indeterminate growth strategy is challenging and poorly understood. Here, we explore the use of two potential techniques for nutrient loading of trembling aspen (Populus tremuloides Michx.) seedlings: (1) exponential fertilization and (2) early shoot growth termination in order to divert assimilated nutrients and carbon to storage rather than to growth. In the first study, aspen seedlings were treated with either exponential or constant fertilization rates, both of which supplied the same amount of nutrients over the growing season. Exponential fertilization resulted in overall poor planting stock form (stunted seedling growth and weak root development) and produced only marginal improvements of nutrient status. As a result, the exponential fertilization regime studied cannot be recommended as a treatment for aspen seedlings. In the second study we treated seedlings with a 2 x 2 factorial combination of fertilization and shoot growth inhibitor (SGI) applications with the fertilizer treatments varying in terms of mid-season fertilizer concentrations. Seedlings with SGI application had much higher tissue nutrient and carbon reserve concentrations than seedlings without a SGI application. In addition, nutrient uptake appeared to be more efficient in SGI treated seedlings, which could potentially result in significant reductions of nutrient application rates during aspen seedling production in nurseries. Overall, early shoot growth termination using a SGI appears to be an effective technique to produce nutrient loaded aspen seedlings.

Plain Language Summary

More trembling aspen seedlings are being planted, but there is little information available for nurseries on how to produce quality aspen seedlings for planting stock. We tested five nursery fertilization regimes to determine which treatment resulted in the best quality seedlings. Seedlings treated with a shoot growth inhibitor and standard fertilization rates had the highest nutritional reserves indicating that this may be an effective recipe for producing high quality aspen seedlings.