Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Late-season fertilization of Picea mariana seedlings under greenhouse culture: biomass and nutrient dynamics. | Ann. For. Sci. 59 2002 255-264 INRA EDP Sciences 2002 DOI forest 2002021 255 Original article Late-season fertilization of Picea mariana seedlings under greenhouse culture biomass and nutrient dynamics Joseph R. Boivin Brad D. Miller and Vic R. Timmer Faculty of Forestry University of Toronto 33 Willcocks Street Toronto Ontario Canada Received 27 March 2001 accepted 9 October 2001 Abstract - Conventional nursery culture of containerized black spruce Picea mariana Mill. . seedlings usually involves a late-season interval commonly called the hardening period when fertilization and water are withheld to promote frost-hardiness. Considerable growth may occur during this time which may lead to internal nutrient dilution a condition often detrimental to subsequent field performance. Continued late season fertilization at 6 or 12 mg N seedling-1 of seedlings during the hardening period was tested as a technique to prevent late season nutrient dilution and possibly to increase nutrient reserves. Root growth was increased much more than shoot growth during this period. Late-season fertilization raised N P and K uptake as much as 164 70 and 32 respectively compared to conventionally fertilized seedlings with no late-season fertilization. Depending on dose rate and pre-hardening nutrient loading this technique demonstrates the potential to build internal nutrient reserves in seedlings. Nutrient dilution was temporarily averted by late-season fertilization suggesting that intensive and prolonged nutrient supplementation during the hardening period may further delay or eliminate nutrient dilution in seedlings. black spruce hardening period nitrogen nutrient dilution nutrient loading Résumé - Fertilisation en fin de saison des plants de Picea mariana cultivés en serre dynamique de la biomasse et des elements nutritifs. Dans les pépinières l elevage en container de plants de Picea mariana Mill. . comporte normalement en fin de saison une phase appelée période d
