Growth, nutrient dynamics, and interspecific competition of nutrient-loaded black spruce seedlings on a boreal mixedwood site

1996 ◽  
Vol 26 (9) ◽  
pp. 1651-1659 ◽  
Author(s):  
V. Malik ◽  
V.R. Timmer

Nutrient-loaded and conventionally fertilized containerized black spruce (Piceamariana (Mill.) BSP) seedlings were planted on a boreal mixedwood site in the Greater Clay Belt of Ontario to study their growth and interaction with natural vegetation. At planting, nutrient-loaded seedlings were similar in height and biomass to conventionally fertilized seedlings, but contained 39, 69, and 22% more tissue N, P, and K content, respectively. After two field growing seasons, nutrient-loaded seedlings attained 15–18% more height and 16–39% more biomass, resulting in 15–27% reduction in the biomass of neighbouring vegetation. Aboveground biomasses of seedlings and neighbouring vegetation were inversely related. Interspecific competition was more intense in the second year than in the first year of outplanting. Nutrient loading prior to planting stimulated nutrient uptake and root growth after planting, and reduced soil N availability by 6–20% during the first season, suggesting greater preemption of belowground nutrient resources. The enhanced competitive ability of loaded seedlings over naturally occurring vegetation was probably due to the contrasting nutrient utilization traits induced by greenhouse fertilization. Nutrient-loaded seedlings translocated more nutrients to actively growing parts from reserves built up during the greenhouse preconditioning phase than did conventionally fertilized seedlings. First-season growth and nutrient responses in the field and in previous greenhouse trials were significantly correlated, demonstrating the effectiveness of using intact bioassays to simulate and predict short-term field responses to competition treatments.

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.


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.


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 843
Author(s):  
Ella R. Gray ◽  
Matthew B. Russell ◽  
Marcella A. Windmuller-Campione

Insects, fungi, and diseases play an important role in forest stand development and subsequently, forest management decisions and treatments. As these disturbance agents commonly occur within and across landscapes, modeling has often been used to inform forest planning and management decisions. However, models are rarely benchmarked, leaving questions about their utility. Here, we assessed the predictive performance of a Bayesian hierarchical model through on–the-ground sampling to explore what features of stand structure or composition may be important factors related to eastern spruce dwarf mistletoe (Arceuthobium pusillum Peck) presence in lowland black spruce (Picea mariana (Mill.) B. S. P.). Twenty-five state-owned stands included in the predictive model were sampled during the 2019 and 2020 growing seasons. Within each stand, data related to the presence of eastern spruce dwarf mistletoe, stand structure, and species composition were collected. The model accurately predicted eastern spruce dwarf mistletoe occurrence for 13 of the 25 stands. The amount of living and dead black spruce basal area differed significantly based on model prediction and observed infestation, but trees per hectare, total living basal area, diameter at breast height, stand age, and species richness were not significantly different. Our results highlight the benefits of model benchmarking to improve model interpretation as well as to inform our understanding of forest health problems across diverse stand conditions.


1984 ◽  
Vol 14 (6) ◽  
pp. 933-939 ◽  
Author(s):  
Hans Nienstaedt

Using 3-year heights, the tallest 49 provenances were selected in a nursery test of 110 black spruce (Piceamariana (Mill.) B.S.P.) provenances. A field test of the selected provenances was planted in Wisconsin; two tests of 108 provenances, both in Minnesota. Characteristics evaluated in the nursery included heights after two, three, and five growing seasons, and growth initiation and cessation in the second and third growing season. Heights were measured in the field tests. Separate statistical analyses, ANOVA and simple correlation, were used for the full complement of provenances and for those that were selected. All nursery characteristics varied significantly; the correlations between latitude and height decreased with age, and were not significant after five season's growth. Differences among provenances in free growth may explain this. Selection at age 3 years was not effective; too many selection errors were evident in the test of the full complement of provenances. Early selection on the basis of heights and phenological characteristics is not an effective way of reducing large range-wide provenance tests to breeding populations.


1994 ◽  
Vol 70 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. L. Fleming ◽  
D. S. Mossa

A series of spot seeding experiments was set out on coarse-textured upland sites in northwestern Ontario to investigate how black spruce (Picea mariana [Mill.] B.S.P.) seedling establishment and growth could be improved by site selection and seedbed preparation. Virtually all germination occurred within the first growing season. Annual seedling mortality rates were greatest during the first year, then declined steadily and stabilized at low levels (<10%) after the third year. The highest fifth-year establishment ratios (seedlings/viable seed sown) were found on seedbeds derived from materials near the mineral soil/humus interface. On wetter sites (i.e., higher Soil Moisture Regimes) the best seedbeds occurred closer to the soil surface. Mean fifth year establishment ratios for the best seedbeds were 0.032 on moderately fresh to fresh sites, 0.146 on very fresh to moderately moist sites, and 0.082 on moist to very moist sites. On adjacent lowland sites, slow-growing, compact Sphagnum mosses had a mean establishment ratio of 0.179. Mean fifth-year seedling heights on upland sites ranged from 12 to 14 cm, and were not strongly correlated with site or seedbed type. Key words: direct seeding, black spruce, seedbed, seedling establishment, site type and germination


Author(s):  
Joan T. D. Suwalsky ◽  
Robert P. Klein ◽  
Martha J. Zaslow ◽  
Beth A. Rabinovich ◽  
Nancy F. Gist

2017 ◽  
Vol 14 (4) ◽  
pp. 755-766 ◽  
Author(s):  
Yingying Tang ◽  
Sarah F. Harpenslager ◽  
Monique M. L. van Kempen ◽  
Evi J. H. Verbaarschot ◽  
Laury M. J. M. Loeffen ◽  
...  

Abstract. The sequestration of nutrients from surface waters by aquatic macrophytes and sediments provides an important service to both natural and constructed wetlands. While emergent species take up nutrients from the sediment, submerged and floating macrophytes filter nutrients directly from the surface water, which may be more efficient in constructed wetlands. It remains unclear, however, whether their efficiency is sufficient for wastewater purification and how plant species and nutrient loading affects nutrient distribution over plants, water and sediment. We therefore determined nutrient removal efficiencies of different vegetation (Azolla filiculoides, Ceratophyllum demersum and Myriophyllum spicatum) and sediment types (clay, peaty clay and peat) at three nutrient input rates, in a full factorial, outdoor mesocosm experiment. At low loading (0.43 mg P m−2 d−1), plant uptake was the main pathway (100 %) for phosphorus (P) removal, while sediments showed a net P release. A. filiculoides and M. spicatum showed the highest biomass production and could be harvested regularly for nutrient recycling, whereas C. demersum was outcompeted by spontaneously developing macrophytes and algae. Higher nutrient loading only stimulated A. filiculoides growth. At higher rates ( ≥  21.4 mg P m−2 d−1), 50–90 % of added P ended up in sediments, with peat sediments becoming more easily saturated. For nitrogen (N), 45–90 % was either taken up by the sediment or lost to the atmosphere at loadings  ≥  62 mg N m−2 d−1. This shows that aquatic macrophytes can indeed function as an efficient nutrient filter but only for low loading rates (polishing) and not for high rates (purification). The outcome of this controlled study not only contributes to our understanding of nutrient dynamics in constructed wetlands but also shows the differential effects of wetland sediment types and plant species. Furthermore, the acquired knowledge may benefit the application of macrophyte harvesting to remove and recycle nutrients from both constructed wetlands and nutrient-loaded natural wetlands.


Author(s):  
W. James Grichar ◽  
Peter A. Dotray ◽  
Todd Baughman

Aims: To determine peanut response and weed control following the use of carfentrazone plus pyroxasulfone (C + P). Study Design:  Randomized complete block design with 3-4 reps depending on location. Place and Duration of Study: Studies were conducted during the 2015 and 2016 growing seasons in south Texas near Yoakum (29.276o N, 97.123o W), the High Plains of Texas near Lamesa (32.769o N, 101.977o W) or Brownfield (33.104o N, 102.161o W), and southwestern Oklahoma near Ft. Cobb (35.091o N, 98.275o W). Methodology: Plots were infested with naturally occurring weed populations. Pendimethalin was applied either preplant incorporated (PPI) or preemergence (PRE). Early postemergence (EPOST) applications varied according to weather conditions and peanut growth at each location. Postemergence (POST) treatments were applied 26 to 58 days after planting. Weed control and peanut stunting were visually estimated on a scale of 0 to 100 (0 indicating no control or plant death and 100 indicating complete control or plant death). Results: Peanut stunting with C + P was only noted at the High Plains and Oklahoma locations in 2015 but not 2016. Urochloa texana (Buckl.) control with C + P (PRE) varied from 75 to 93%. POST applications provided inconsistent control.  Amaranthus palmeri S. Wats. control with C + P (PRE) was at least 78% season-long while POST applications were inconsistent (24 to 100%).  Pendimethalin plus C + P controlled Cucumis melo L. var. Dudaim Naud. at least 80% late-season. Ipomoea hederacea Jacq. control was excellent season-long (> 80%) in 2015 but poor (< 60%) in 2016.  Reduced peanut yields were noted with C + P in Oklahoma in 2015 to excessive season-long injury.    Conclusion: The premix of C + P has potential for use in peanut especially for control of many small-seeded annual broadleaf weeds that continue to plague many peanut growers across the southwest.  For effective broad-spectrum annual weed control season-long, the addition of pendimethalin to PRE applications will be required.


2014 ◽  
Vol 42 (2) ◽  
pp. 516-522 ◽  
Author(s):  
Okan OZKAYA ◽  
Songül ÇÖMLEKÇIOGLU ◽  
Hatice DEMIRCIOGLU

The fig fruit is a unique, climacteric, highly perishable subject to rapid physiological breakdown. Application of 1-methylcyclopropene (1-MCP) was tested to delay ripening of black fig (Ficus carica L. cv. ‘Bursa Siyahi’) during storage overtwo growing seasons. Fruits were pre-cooled to 1 °C for 6 hours and afterwards treated with 500 or 1000 nl l-1 of 1-MCP for24 hours. Treated fruits were stored for 10 days at 1 °C, 90-95% RH and then evaluated. 1-MCP treatments showed thatethylene production, respiration rate, weight loss and concentrations of glucose, fructose and total soluble solids (TSS) were negatively correlated to the 1-MCP doses during cold storage (with the exception of TSS in the first year of experiment and respiration rate in the second year of the experiment). In contrast, pulp firmness and colour (ho) during cold storage werepositively correlated to the 1-MCP applied doses. Results of this study showed that although 1-methylcyclopropene applications slowed down fruit softening during the 10 days of storage, 1-methylcyclopropene appeared to have a relatively limited effect on slowing ripening of ‘Bursa Siyahi’ figs.


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