Exponential fertilization increases nutrient uptake and ectomycorrhizal development of black spruce seedlings

1998 ◽  
Vol 28 (5) ◽  
pp. 674-682 ◽  
Author(s):  
A M Quoreshi ◽  
V R Timmer

Intensive fertilization may inhibit adequate mycorrhizal development for forest nursery stock production. Containerized black spruce (Picea mariana (Mill.) BSP) seedlings exposed to four fertilization regimes (one conventional and three exponential at 12.5, 12.5, 25, and 50 mg N/seedling, respectively) and two ectomycorrhizal inoculations (Hebeloma crustuliniforme (Bull. ex St-Amans) Quel. and Laccaria bicolor (R. Mre.) Orton) were grown from seed to assess mycorrhizal formation and nutrition of young trees under intensive greenhouse culture. Exponentially increasing fertilizer additions stimulated ectomycorrhizal development (49-85%) compared with conventional constant-rate fertilization (22-26%). Exponential fertilization also increased seedling N (13-34%) and P (5-18%) uptake, although dry matter production was reduced (17-25%) at the lowest exponential addition rate. Ectomycorrhizal inoculation did not affect seedling biomass but increased uptake of N (6-17%), P (5-20%), and K (4-18%), demonstrating a potential for nutrient loading by fungi. Higher ectomycorrhizal formation found under exponential fertilization regimes was attributed to lower initial nutrient levels maintained in the growing media. Results indicate that high exponential fertilization combined with fungal inoculation may be effective for producing both nutrient-loaded and ectomycorrhizally infected planting stock.


1999 ◽  
Vol 29 (4) ◽  
pp. 474-486 ◽  
Author(s):  
Moses Imo ◽  
Victor R Timmer

Impacts of methods to overcome competing vegetation (fertilization, herbicide application, and shading) on conventional and nutrient-loaded black spruce (Picea mariana (Mill.) BSP) seedlings were examined on six forest site types in northeastern Ontario using vector competition analysis. Four sites (Alnus; hardwood; mixedwood, herb rich; and mixedwood, herb poor) were selected to represent high competition, and two sites (feathermoss and Vaccinium) to represent low-competition forest sites. Although similar in biomass before planting, loaded seedlings had greater N, P, and K content than nonloaded seedlings. After planting, loaded seedlings outperformed growth of nonloaded seedlings under all vegetation-control treatments on all sites. Herbicide application eliminated noncrop vegetation but resulted in significantly higher seedling biomass only on the high-competition Alnus site. Field fertilization stimulated weed growth resulting in seedling suppression on the high-competition sites, while nutrient loading countered weed competition on most sites. Interpretation of these results by vector competition analysis revealed that, without fertilization, competition for nutrients was the primary factor limiting seedling growth, while competition for light and (or) moisture was greater after fertilizer addition on weed-prone sites. Similar interpretation revealed no seedling-weed interactions in the less competitive sites.



2000 ◽  
Vol 30 (2) ◽  
pp. 191-201 ◽  
Author(s):  
M Quoreshi ◽  
V R Timmer

Containerized black spruce (Picea mariana (Mill.) BSP) seedlings fertilized conventionally (12.5 mg N/plant) or exponentially (12.5, 25, or 50 mg N/plant) and inoculated with Hebeloma crustuliniforme (Bull. Ex St-Amans) Quel. or Laccaria bicolor (R. Mre.) Orton were periodically monitored for a 20-week greenhouse rotation to assess growth dynamics, steady-state N and P nutrition, and ectomycorrhizal development. Growth and nutrient accumulation increased exponentially for the exponential regimes and more linearly for the conventional regime, although final biomass was similar except for the low-dose exponential addition. Shoot/root biomass ratios were relatively stable for most of the growing season, characterizing steady-state nutrient supply that benefits seedling outplanting performance and mycorrhizal colonization. Exponential fertilization also stimulated mycorrhiza formation even at high loading (25 or 50 mg N) rates that build up nutrient reserves in the seedlings without affecting seedling size. Plant nutrient uptake was more efficient under exponential fertilization and (or) fungal colonization, although efficiency dropped off at high loading levels. Vector nutrient diagnosis revealed marked nutrient dilution under conventional fertilization, but steady-state nutrition under exponential fertilization that coincided with satisfactory mycorrhiza development on seedlings. Dilution-free nutrient conditions for seedlings may provide stable carbohydrates for symbiosis and may develop enhanced tolerance to high fertilizer inputs.



2001 ◽  
Vol 31 (8) ◽  
pp. 1357-1366 ◽  
Author(s):  
Moses Imo ◽  
Victor R Timmer

Enhanced nutrient mobilization from old to current growth is a key mechanism that confers competitive ability to nutrient-loaded black spruce (Picea mariana (Mill.) BSP) seedlings planted on high-competition forest sites in northern Ontario. This study examines effects of nutrient loading and differing vegetation management (herbicide, fertilization, shading) on growth, partitioning, and net retranslocation of N between current and old shoots of newly planted black spruce seedlings on six contrasting boreal sites. Nutrient loading during nursery culture improved seedling growth and N uptake and retranslocation after transplanting. Herbicide application accelerated growth and N uptake only on the high-competition Alnus, hardwood, and mixedwood sites but had no effect on the less competitive feathermoss and Vaccinium sites. Weed removal on competitive sites reduced N retranslocation significantly. Field fertilization reduced N retranslocation in seedlings and promoting tree growth and N uptake on the less competitive feathermoss and Vaccinium sites. However, fertilization stimulated weeds on high-competition sites suppressing seedling biomass and N uptake. Factors that seem to affect net N retranslocation include the type and level of internal N reserves, biomass and N accumulation and partitioning, external N supply, and other stresses that limit plant growth such as competition.



2000 ◽  
Vol 30 (5) ◽  
pp. 744-752 ◽  
Author(s):  
A M Quoreshi ◽  
V R Timmer

Early growth potential of nutrient-loaded and (or) Laccaria bicolor (R. Mre.) Orton inoculated (Picea mariana (Mill.) BSP) seedlings was investigated using pot bioassays retrieved from a low-competition feathermoss site and a high competition hardwood-Alnus site in the boreal forest. Mycorrhizal seedlings were similar in biomass and shoot/root ratio to nonmycorrhizal seedlings at planting but significantly higher in nutrient content depending on fertilization regime and loading rate. After transplanting, both nutrient-loaded and inoculated seedlings outperformed conventional seedlings, increasing dry matter production by 20-49% with loading and by 45-92% with combined treatments. Nutrient uptake followed similar trends, increasing N, P, and K uptake by 80-124, 89-129, and 72-106%, respectively, for combined treatments compared with conventional seedlings, demonstrating the advantage of both nutrient loading and inoculation in early plantation establishment. Seedling response was greater on the feathermoss site, presumably because of less competition for nutrients and light. Vector diagnosis indicated the response was associated with a primary limitation of N and P that was alleviated by nutrient loading and mycorrhizal inoculation, particularly when treatments were combined. A strong correlation between preplant N content and outplant biomass suggests that initial nutritional status is a better criterion for predicting stock quality than traditional morphological parameters of seedlings.



1984 ◽  
Vol 14 (4) ◽  
pp. 554-558 ◽  
Author(s):  
M. E. Krasny ◽  
K. A. Vogt ◽  
J. C. Zasada

Root and shoot biomass and mycorrhizal development were examined for white spruce (Piceaglauca (Moench) Voss) seedlings naturally regenerating in four floodplain communities in the boreal forest. Mean seedling biomass was highest in the open community and lowest in the spruce community. Seedlings growing in the open community had higher root:shoot ratios (0.50) compared with seedlings growing in the willow (0.34), alder (0.20), and spruce (0.24) communities. Essentially all short roots of spruce seedlings growing in all four communities were infected by mycorrhizal fungi throughout the growing season.



1988 ◽  
Vol 18 (7) ◽  
pp. 962-964 ◽  
Author(s):  
Hank A. Margolis ◽  
Jacques Bégin ◽  
Richard Beeson ◽  
Pierre Bellefleur

Containerized black spruce seedlings (Piceamariana (Mill.) B.S.P.) were grown at the greenhouse at CIP Inc., Harrington, Québec, from February until May, 1987. We wished to test whether differences in the quantity and quality of light received from two commercially available lamps during photoperiod extension would alter the allocation of carbon between lignin and cellulose in shoots and roots. Photoperiods were extended from 17:00 to 01:00 using either metal halide and high-pressure sodium lamps together or high-pressure sodium lamps alone. At night, the treatment using both types of lamp together increased the photon flux density of blue light (400–500 nm) at seedling height 10-fold, from 0.32 to 3.2 μE m−2 s−1. Photosynthetically active radiation was increased 4-fold, from 4.5 to 17.9 μE m−2 s−1. Total seedling biomass did not differ statistically between light treatments at any given time. However, seedling biomass averaged over all times was statistically higher (p ≤ 0.03) for seedlings in the treatment using both types of lamp together. Percent lignin, percent cellulose, and lignin to cellulose ratios were not significantly affected by the light source used during photoperiod extension. As expected, percent lignin and percent cellulose in shoots and roots increased significantly with time. The percentage of seedlings judged unacceptable because of spiralized stems was not affected by light source and averaged 21.9%.



1970 ◽  
Vol 46 (6) ◽  
pp. 470-472 ◽  
Author(s):  
George E. MacKinnon

An average of 17 million tubed seedlings were planted annually in the Province of Ontario from 1966 to 1969. Plans call for increasing the programme to an estimated 20 million tubed seedlings in 1971.Tubed seedlings provide a supply of seedling stock, which can be planted during the summer months, making the best use of available labour supply. Other advantages are ease of planting on shallow-soiled sites, ease of handling, low planting costs, and flexibility provided by production of seedlings on short notice to meet immediate needs. The principal species grown are black spruce, white spruce, jack pine, red pine and white pine. The ground is generally site prepared prior to planting by mechanical scarification or prescribed burning. Planting is carried out at average spacing of 1,000 trees per acre. Survival figures of recent planting, after one year, indicate survival comparable to that of standard bare-rooted nursery stock.



1998 ◽  
Vol 28 (2) ◽  
pp. 206-215 ◽  
Author(s):  
V Malik ◽  
V R Timmer

Black spruce (Picea mariana (Mill.) BSP) seedlings were exponentially nutrient loaded by applying 3 or 6 times more fertilizer than recommended for conventional seedling production in the nursery. Loaded seedlings were similar in height and biomass to nonloaded seedlings after nursery culture, but their tissue N, P, and K content was almost twice as much as that of nonloaded seedlings. The seedlings were transplanted on intact potted substrates (bioassays) retrieved with natural vegetation from two boreal mixedwood sites and grown for one season in a greenhouse to study early- and late-season growth and nutrient dynamics, and nutrient loading and herbicide effects on N retranslocation processes. After transplanting, height and biomass growth of loaded seedlings were, respectively, 9-14% and 24-49% more than nonloaded seedlings in herbicide-treated plots, and 14-32% and 42-85% more in untreated plots, resulting in 32-39% biomass reduction in natural vegetation. The effect of nutrient loading on growth was attributed to earlier and greater biomass and N partitioning to current needles and roots that promoted N uptake (up to 20.9 ± 1.7 mg) compared with nonloaded seedlings (up to 11.8 ± 1.2 mg). Although both loading and herbicide treatments stimulated seedling growth and N uptake, N retranslocation from older to actively growing tissues was promoted by loading but reduced by herbicide treatment. The results demonstrate the high dependence of seedlings on internal nutrient reserves when planted in competitive environments, and that nutrient retranslocation is mainly driven by current growth, nutrient uptake, and internal nutrient reserves.



2002 ◽  
Vol 32 (11) ◽  
pp. 2022-2031 ◽  
Author(s):  
Anna Wallstedt ◽  
Andrew Coughlan ◽  
Alison D Munson ◽  
Marie-Charlotte Nilsson ◽  
Hank A Margolis

Sites dominated by Kalmia angustifolia L. are often associated with slow decomposition of organic matter, decreased nitrogen (N) mineralization rates, and low black spruce (Picea mariana (Mill.) BSP) productivity. The objective of this study was to separate the effects of belowground competition by Kalmia from the effects of water-soluble soil phenols on black spruce seedlings growing under different levels of Kalmia cover. A factorial greenhouse bioassay was established in which black spruce seedlings were grown for 6 months in intact blocks of soil with three different levels of Kalmia cover. The soil was treated with charcoal to reduce the amounts of water-soluble phenols, and (or) tubes were inserted to exclude Kalmia roots. At low Kalmia cover, reducing the level of belowground competition increased seedling biomass by 134%. However, reducing belowground competition did not increase seedling biomass at the two higher levels of Kalmia cover. It is possible that seedling biomass remained low because of an increased immobilization of N in the organic layer. Furthermore, the proportion of ectomycorrhiza morphotypes differed among seedlings growing under different levels of Kalmia cover. The effect of water-soluble phenols on seedling growth remains uncertain, since we observed a confounding effect of the charcoal treatment on soil microbial biomass and seedling response.



2021 ◽  
Vol 49 (2) ◽  
pp. 12244
Author(s):  
Xiuli CHU ◽  
Xianyou LUO ◽  
Zhichun ZHOU

Exponential fertilization (EF) can feed seedlings with more nutrients than needed for growth and continuous lighting is expected to reduce the risk of loading at high application rate. In this study, red-seed tree (Ormosia hosiei Hemsley & E. H. Wilson) seedlings were raised by EF at a low rate of 160 mg nitrogen (N) plant-1 (conventional) (N-phosphorus [P]-potassium [K], 12-9-12) and a high rate of 600 mg N plant-1 (intensive), which was adapted from previous studies with large-pot-seedlings. Both fertilizer regimes were nested to either of two light spectra from high-pressure sodium (HPS) and light-emitting diode (LED) sources with three replicates for each combined treatment. Seedlings subjected to the conventional regime in the LED spectrum showed better growth and greater biomass accumulation with higher leaf N and P contents than other ones. In the conventional fertilizer regime, the LED spectrum also resulted in higher photosynthesis shown by more pigments and higher N synthesis than the HPS spectrum. The HPS spectrum strengthened P synthesis in the intensive regime. The antioxidative activity was stimulated by a high dose of EF, hence excessive toxicity was likely induced. We recommend using the normal rate of 160 mg N plant-1 for the culture of red-seed tree seedlings with LED lighting to promote seedling quality without causing excessive nutrient toxicity.



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