1,720,973 research outputs found
Snow crab waste-derived carbon nanofertilizers: effects of foliar and soil application on growth, yield, and phytonutrients of lettuce cultivated in a controlled environment
No full textCarbon nanofertilizers (CNFs) have gained significant attention in agriculture due to their nanoscale properties, which enhance nutrient uptake, photosynthesis, plant health, and crop yield while reducing the frequency of application and minimizing environmental pollution. This study investigated the effects of CNFs derived from snow crab waste on lettuce growth, yield, and phytonutrient composition using both foliar and soil drench applications under controlled conditions. Foliar application of CNFs demonstrated a positive impact on lettuce growth by increasing leaf number, leaf area (LA), chlorophyll content, and biomass production. It also enhanced ammonium and nitrate uptake and significantly improved the phytonutrient profile, including vitamins, phenolics, total soluble sugars, total antioxidants and protein content. The results indicated that foliar application is an effective strategy for rapid nutrient absorption, leading to improved plant metabolism and overall crop quality. Soil drench application of CNFs improved soil fertility by facilitating controlled nutrient release and reducing nutrient losses. This method positively influenced root growth, chlorophyll content, and phytonutrient accumulation, leading to sustained crop productivity. Synthetic fertilizer (NPK) resulted in higher growth and yield, though CNF treatment produced a comparable yield while enhancing minerals, total antioxidants, and total phenolic compounds. These findings highlight the potential of repurposing seafood waste into CNFs that can enhance soil fertility and plant nutrition. Future research should focus on optimizing CNF formulations for various crops, assessing long-term soil health impacts, and evaluating environmental sustainability to promote the broader adoption of CNFs in modern agriculture
Assessing the potential of cover crop mixtures in a faba bean cropping system under boreal climatic conditions
No full textPoor soil conditions and boreal climatic conditions in Newfoundland and Labrador (NL) are the major constraints in the establishment of cover crop (CC) mixtures. CC mixtures were grown as an additional forage source, which not only provided biomass but also balanced soil C:N ratio, scavenged N and improved soil health. An experiment (June 2022- September 2023) was conducted in Pasadena, NL, where fourteen CCs mixtures were introduced in a faba bean cropping system. The combinations composed of two-way and three-way CC species of legumes [red clover (RC), berseem clover (BC), hairy vetch (HV) and birdsfoot trefoil (BT)] and cereals [fall rye (CR), annual ryegrass (AR) and triticale (TR)] in a randomized complete block design. The results showed that CC mixtures were successfully established and highest DMY was observed for HVCR and RCCR. While BCAR and RCAR exhibited better fodder quality as compared to other CC mixtures. CC mixtures also improved the forage quality of the faba bean, weed suppression and benefit-cost-ratio. However, CC mixtures have a non-significant impact on faba bean yield stability. CC mixtures had a significant impact on SMBC while no significant effects on POX-C, POM-N, POM-C, MBN, and soil mineral N. PLFA analysis showed that CC mixtures have significant impact on G⁻, G⁺, total bacterial population and total PLFA content while had no significant effects on fungi and protozoa population. This research concluded that CC mixtures showed good DMY and forage quality along with improvement in weed suppression, benefit-cost-ratio, SMBC, and bacterial population.Includes bibliographical reference
Effect of crop rotation and different nitrogen sources on soil water retention and silage corn forage yield and quality in boreal climate
No full textBy implementing crop rotation and different nitrogen (N) sources, farmers can improve soil properties, leading to increased soil water retention (SWR) and ultimately enhancing crop yield and quality. This thesis research aimed to examine the impact of crop rotation and N sources on SWR, silage corn yield, and quality in boreal climates. A field trial was established in 2019 – 2021. Treatments were arranged in a split-plot design with four replicates. Rotation sequences were the main plots, and N sources were the subplots. Three models (van Genuchten, Brooks & Corey, and Durner) were applied to predict SWR curves (SWRC). The van Genuchten and Durner models provided more accurate predictions of SWRC than the Brooks & Corey model. Corn-corn-corn*agrotain (AG) showed superior agronomic performance and produced 17.75 Mg h-1 of forage yield compared to all others intreactions. SuperUTM produced higher non-fibrous carbohydrates, whereas AG produced higher forage energies (net energy of laction, net enery of gain, net enery of maintenance) and total digestible nutrient (TDN), than control. These findings suggest that AG and SU could be suitable choices to attain high forage yield and quality for dairy livestock under boreal climate.Includes bibliographical reference
Effect of natural media amendments on crop quality under controlled environmental conditions
No full textThe effect of different natural media amendments on the physical, chemical, and biological properties of soil is well studied and documented. Although there is more information on changes in soil parameters, few studies have demonstrated effects on crop quality. Herein, a greenhouse study was set up to identify the effect of wood ash (WA), paper sludge (SL), biochar (BC), and its combinations on kale’s nutritional profile grown in two different soil types (soil type 1, soil type 2) in Newfoundland, Canada. Pathway analysis revealed that although the same media amendments were used, the kale quality parameters were significantly altered by the grown soil type. It was shown that for soil type 2, most of the parameters were significantly enhanced compared to CTL (control) (p<0.05). For soil type 1, upon the addition of WA, SL, and BC there was a significant increase in the marketable yield; however, the crop’s nutritional parameters were not significantly changed. The lipidomics results showed that for soil type 1, WSBC (wood ash+sludge+biochar) amendment appeared to be effective in enhancing the functional lipids of 1,2 DGs, 1,3 DGs, ω6 lipids, and phospholipids. Whereas in kale grown in soil type 2, most of the studied functional lipids were increased upon the addition of SL and WBC (wood ash+biochar) media amendment. This different impact of media amendments on soils was also suggested from the pathway analysis revealing significantly different (p<0.05) lipid pathways associated with each soil type. In conclusion, WA, SL, and BC and the combination amendments showed a positive effect on kale’s nutritional profile, and this approach can be used to produce functional foods in controlled environmental conditions.Includes bibliographical reference
Non-invasive estimation of soil hydraulic parameters in boreal podzolic soils using ground-penetrating radar and hyrological models
No full textObtaining information on soil hydraulic parameters (SHPs), including their spatiotemporal variation, is fundamental to understanding flow and transport processes in the vadose zone. This research examined the potential of coupling time-lapse ground-penetrating radar direct ground wave (GPR-DGW) information with hydrological models for non-invasive estimation of SHPs in a boreal podzolic soil using two experimental studies. The first research study focused on estimating soil water content (SWC) variation in podzolic soil using GPR-DGW and predicting field-saturated hydraulic conductivity (Kfₛ) by integrating the estimated SWC variations into the Green-Ampt (GA) model. The second study investigated the potential of integrating SWC variation derived from GPR-DGW in the Hydrus-1D model for obtaining Mualem-van Genuchten (M-vG) parameters and simulating soil water dynamics. Both studies involved short-term Beerkan infiltration experiments monitored using a surface GPR system of 500 MHz center frequency, collecting time-lapsed traces every 5 s. The first study revealed that GPR-DGW can successfully provide continuous, reliable SWC variation data during a short-term infiltration, which proved useful in obtaining probable Kfₛ values from the GA model. The second study also found that reliable M-vG parameters can be obtained through the inversion of SWC variations from GPR-DGW in the Hydrus-1D model. In addition, good correlations were observed between measured SWC variation and those simulated using the inverted M-vG parameters. Overall, this research demonstrates a significant advancement in using GPR as a reliable and robust technique for large-scale SHPs prediction in boreal podzolic soils, with the possibility of extending to other soil types in future research.Includes bibliographical reference
Effects of vermicompost on soil physicochemical properties, kale (Brassica oleracea) crop growth and yield in Newfoundland podzolic soils
No full textNewfoundland and Labrador’s (NL) agricultural development faces challenges due to adverse weather, soil acidity, and low fertility. The pulp and paper industry generates large amounts of sludge or biosolids, which are often incinerated or disposed of in landfills without exploring organic waste recycling alternatives. Paper sludge (PS), a byproduct of Corner Brook Pulp and Paper Ltd., is a potential liming and nutrient source that offers a promising solution as a soil amendment due to its high pH and essential plant nutrients. Vermicomposting offers a more sustainable alternative compared to incineration, particularly because paper sludge has high water content, which lowers its calorific value and makes combustion inefficient. Additionally, its high nitrogen content, when combusted, contributes to nitrogen oxide emissions rather than being recycled as a nutrient, further reducing the sustainability of incineration. By converting PS into vermicompost and using it as an amendment, its use can further enhance soil properties by improving the physicochemical characteristics.
The first study assessed the impact of different vermicompost-to-soil ratios (0:100, 15:85, 30:70, 45:55) on soil physicochemical properties, and the second study evaluated the agronomic effect of vermicompost made from PS on the growth and yield of kale (Brassica oleracea). A pot experiment with nine soil (Orthic Ferro-Humic Podzol), vermicompost, and urea combinations was conducted in a controlled environment for the second study. Except for the 0:100 mix (with 100% N), urea levels were set at 0 and 50% of the N required by kale. Findings from the first study (Physicochemical properties) revealed that vermicompost application significantly lowered soil bulk density by 17.8–58.1% and increased total carbon by 133%–470%, total nitrogen (N) by 102–302%, organic matter by 64–1107% and soil porosity by 15.5–41.8% compared to the control. Results of the second study (Growth chamber experiment) showed that vermicompost-enriched soils significantly enhanced kale growth, increasing shoot mass by 57–120 g per plant, height by 8–12 cm per plant, and leaf count by 5–9 leaves per plant. This study highlights PS-derived vermicompost as a solution to improve the fertility of NL’s podzolic soils, supporting crop growth while replacing a considerable amount of synthetic fertilizer, promoting organic waste recycling, and contributing to local food security
Soil fertility characterization in podzolic soils of western Newfoundland using electromagnetic induction (EMI) sensors
No full textThis study was conducted to assess the possibility of predicting soil fertility properties in western Newfoundland using multi-coil (MC) and multi-frequency (MF) electromagnetic induction (EMI) sensors. Two studies on podzolic boreal soils evaluated the effectiveness of apparent electrical conductivity (ECa) and apparent magnetic susceptibility (MSa) from both MC and MF EMI sensors in characterizing available nitrogen (N), phosphorus (P) and soil organic matter (SOM) as significant soil fertility properties. The first study evaluated the effectiveness of MC and MF-EMI sensors to estimate soil ammonium (NH4+), nitrate (NO3-) and orthophosphate (PO43-) using ECa as a proxy under two different land uses. The second study assessed the effectiveness of MSa obtained from the MC and MF-EMI sensors to estimate and map SOM using a statistical and geostatistical analysis. The first study revealed the potential application of EMI ECa as a proxy to assess the spatial variability of NH4+, NO3- and PO43- within a narrow range of concentrations for a specific site. A comparison between statistical and geostatistical analysis in the second study suggested that cokriging of SOM with densely sampled EMI MSa could provide higher accuracy in estimating and mapping SOM in podzolic soil. Both studies revealed that multiple linear regression models were more effective with the inclusion of soil water than simple linear regression models in predicting soil nutrients and SOM. However, the MC EMI sensor provided a better estimation of soil nutrients, whereas the MF-EMI sensor predicted SOM more effectively. The overall findings from this study demonstrated the potential of EMI sensors as a more accurate and robust method than conventional methods to evaluate and map soil fertility properties in boreal podzolic soils. Further studies are required to assess the potential of EMI sensors under different crop types, management practices, and moisture regimes to estimate and map soil fertility properties for podzolic soils
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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