Graduate Theses & Dissertations

Pages

AN INTEGRATED APPROACH TO WASTEWATER MANAGEMENT AND REUSE IN JORDAN
This research explores the obstacles Jordan is facing regarding the sustainable treatment and reuse of wastewater in the agricultural sector. It assesses the technical, socio-cultural, and political aspects of decision-making around water and wastewater management in Jordan by focusing on a case study involving wastewater usage in the Jordan Valley. It includes a literature review and interviews with representatives of key stakeholders. While at one level wastewater treatment is a technical process with technological solutions, a nuanced understanding of the non-technical challenges facing the wastewater treatment sector in Jordan is necessary. These challenges are inherently embedded in and contextualized by a series of historical, complex and dynamic political and socio-cultural issues involving stakeholders at local and national levels. Only through an interdisciplinary approach with real stakeholder engagement will meaningful solutions to these challenges be developed and implemented, and at least a portion of Jordan's water needs be meaningfully addressed. Author Keywords: Agriculture, Jordan Valley, Political challenges, Sociocultural challenges, Technical challenges, wastewater management
EVALUATION OF HAYFIELD MANAGEMENT STRATEGIES AND BOBOLINK TERRITORIAL HABITAT IN SOUTHERN ONTARIO
I implemented three hayfield management regimens in southern Ontario (a typical schedule at the farmer`s discretion, a delayed first harvest after July 14, and an early first harvest before June 1 with 65 days before second harvest), and evaluated the costs/benefits to farmers regarding hay quality and feasibility, and to Bobolinks (Dolichonyx oryzivorus) regarding reproductive activity and phenology. Typical management resulted in little to no Bobolink reproductive success, and early harvested sites were not (re)colonized. On delayed harvest sites Bobolinks experienced high reproductive success, but hay quality fell below ideal protein levels for most cattle before harvest. I also examined the habitat features Bobolinks use as the basis for establishing territories and associations between Bobolink territory size and habitat quality. I compared vegetation structure, patch size, and prey abundance between small and large territories. Small territories typically occurred on smaller fields with more preferred vegetation characteristics and greater prey abundance. Author Keywords: agro-ecosystem, Bobolink, Dolichonyx oryzivorus, grassland birds, hayfield management
An Analysis of Zoning By-laws and Urban Agriculture in the City of Peterborough, Ontario
Urban agriculture (UA) is becoming increasingly prevalent in Canadian cities. Despite this municipal zoning by-laws often do not address UA explicitly. Using eleven interviews of urban agricultural participants a case study of the City of Peterborough’s zoning by-laws and the barriers they might present to UA was conducted. Research suggests that UA can provide many benefits to urban areas. The analysis found that the City of Peterborough’s zoning by-laws do not directly address UA. In order to enable the development of UA in the City of Peterborough its zoning by-laws will need to be redesigned to address and regulate UA directly. Author Keywords: By-laws, food systems, land use, municipal planning, urban agriculture, zoning
Soil mineralizable nitrogen as an indicator of soil nitrogen supply for grain corn in southwestern Ontario
Soil mineralizable nitrogen (N) is the main component of soil N supply in humid temperate regions and should be considered in N fertilizer recommendations. The objectives of this study were to determine the potentially mineralizable N parameters, and improve N fertilizer recommendations by evaluating a suite of soil N tests in southwestern Ontario. The study was conducted over the 2013 and 2014 growing seasons using 19 field sites across southwestern Ontario. The average potentially mineralizable N (N0) and readily mineralizable N (Pool I) were 147 mg kg-1 and 42 mg kg-1, respectively. Pool I was the only soil N test that successfully predicted RY in 2013. The PPNT and water soluble N (WSN) concentration (0-30cm depth) at planting were the best predictors of fertilizer N requirement when combing data from 2013 and 2014. When soils were categorized based on soil texture, the relationships also improved. Our findings suggest that N fertilizer recommendations for grain corn can be improved, however, further field validations are required. Author Keywords: corn, nitrogen, nitrogen mineralization, soil nitrogen supply, soil N test, southwestern Ontario
Nitrogen and phosphorus bioavailability in soil amended with alkaline stabilized biosolids
Agricultural land application of biosolids recycles nutrients and organic matter to the soil, however the effect of treatment process on nutrient availability requires further research for better nutrient management. This study examined the bioavailability of nitrogen (N) and phosphorus (P) in alkaline treated biosolids (TB) when amended into three different soils. Despite a 45% reduction in total N and P content during treatment, TB did not show reduced N or P availability compared with sewage sludge (SS). Results of a corn growth experiment and a soil incubation showed that TB amendment resulted in little mineralization and generally net immobilization of N, and 2% total P availability to corn from TB. Results suggest that TB are not a source of bioavailable N in the short-term, but can be used as a P amendment for corn. Nutrient management of agricultural land receiving these materials should focus on P added and liming properties. Author Keywords: Alkaline treated biosolids, Nitrogen, Phosphorus, Soil fertility
Legume species, nitrogen rate and arbuscular mycorrhizal fungi inoculation effects on crop biomass and nitrogen requirement in a corn-legume system
Interseeding legume cover crops in grain corn may improve the environmental sustainability of corn production system in Southern Ontario. This study aimed to assess the effects of legume species, nitrogen (N) fertilizer rate and arbuscular mycorrhizal fungi (AMF) inoculation on biomass and N requirement in a corn-legume system. Corn was grown with red clover (RCl), microclover (MCl), hairy vetch (HV), or beans at 10 and 80 kg N ha-1 rates with and without AMF inoculation in a greenhouse for 7 weeks. Corn dry matter (DM) and N uptake were reduced by beans and HV (average 35%) compared with control; however, the DM for beans and HV was 7 and 3 times higher than RCl and MCl, respectively. The N2 fixation ability was similar among legume species and no significant N transfer from legume was detected. Overall, species collection was critical to the success of incorporating legumes into grain corn production. Author Keywords: Arbuscular mycorrhizal fungi, corn, legume cover crop, nitrogen
Regulation of Cytokinins During Kernel Development in High and Low Yielding Oat and Barley Lines
Cytokinins (CKs) are a family of plant phytohormones responsible for many areas of plant growth and development. There are four free base types of CKs found in higher plants, trans-zeatin (tZ), N6-(∆2-isopentenyl)adenine (iP), cis-Zeatin (cZ) and dihydrozeatin (DZ). CK biosynthesis is regulated by adenosine phosphate-isopentenyltransferase (IPT), which is encoded by a multi-gene family in many plant species. There are two types of IPT pathways responsible for CK production, the tRNA pathway and the AMP (ATP/ADP) pathway. The tRNA pathway putatively produces cZ and the latter predominantly produces iP type nucleotides. CKs have long been studied for their role in stress tolerance, signal transduction, and involvement in many areas of plant growth and development. This study focuses on the role of CKs and CK biosynthesis by IPT during kernel development and comparisons of its regulation in high and low yielding barley and oat lines. The sequence of a putative IPT encoding gene in barley and oat was identified by a blast search of other known IPT gene fragments in closely related species. Quantitative Real time PCR results based on primers designed for the putative barley and oat IPT gene revealed changes in expression of IPT during different stages of kernel development, but no significance difference was associated with yield. Correlation of IPT gene expression in barley with cZ CK profiles measured by HPLC-MS/MS, confirms a putative IPT gene is a tRNA- IPT. HPLC-MS/MS results reveal some CK types, such as benzyladenine, are more predominant in higher yielding lines. This suggests different types of CKs play a role in yield production. Future studies on more IPT genes in the barley and oat IPT gene family will outline a more clear representation of the role of IPT in barley kernel development. Author Keywords: Benzyladenine, Cereal grain, Cytokinin, Isopentenyl Transferase, Mass Spectrometry, Real Time PCR
Canid Predation of Domestic Sheep (Ovis aries) on Ontario Farms
Livestock predation by wild predators is a frequent and complicated issue, often cited as a significant factor in the decline of livestock production and justification for killing predators. Coyotes (Canis latrans) are the primary predators of sheep in Ontario. Some farms appear to be more susceptible to predation than others, despite the use of mitigation techniques. I explored land cover in the vicinity of farms as a potential influence on the level of predation, as coyote abundance and wild prey are correlated with certain habitat types. Using model competition, I show that landscape explains little variation in predation levels over all farms, but can explain 27% of variation in the percent of a flock killed. Total forest edge habitat and distance between forest patches were both positively associated with losses, suggesting a reduction in forest cover surrounding a farm puts the flock at greater risk. In addition, I tested four disruptive deterrents for effectiveness at protecting flocks. A matched-pairs analysis did not show a statistically significant benefit of these non-lethal mitigation tools. Author Keywords: Alternative Prey, Canis latrans, Coyote, Landscape, Predation Deterrents, Sheep
Agro-Ecological Zoning (AEZ) of Southern Ontario and the Projected Shifts Caused by Climate Change in the Long-term Future
This thesis proposes an agro-ecological zoning (AEZ) methodology of southern Ontario for the characterization and mapping of agro-ecological zones during the historical term (1981-2010), and their shifts into the long-term (2041-2070) projected climate period. Agro-ecological zones are homogenous areas with a unique combination of climate, soil, and landscape features that are important for crop growth. Future climate variables were derived from Earth System Models (EMSs) using a high emission climate forcing scenario from the Intergovernmental Panel on Climate Change 5th Assessment Report. The spatiotemporal shifts in agro-ecological zones with projected climate change are analyzed using the changes to the length of growing period (LGP) and crop heat units (CHU), and their manifestation in agro-climatic zones (ACZ). There are significant increases to the LGP and CHU into the long-term future. Two historical ACZs exist in the long-term future, and have decreased in area and shifted northward from their historical locations. Author Keywords: Agro-climatic Zones, Agro-ecological Zones, Agro-ecological Zoning, Climate Change, Crop Heat Units, Length of Growing Period
Cultivating Change
The global food system has been criticized for being environmentally, economically and socially unsustainable. As part of a local food movement, farmers’ markets (FM) are undergoing a revival in response to the escalating food system globalization of the past century. Despite the prevalence of FMs as formalized organizations, there remains a significant range in their operational strategies. Through 41 questionnaires and 17 interviews with market administrators across Ontario, in collaboration with the Haliburton County Farmers’ Market Association, I explored these strategies and analyzed the influence of community characteristics on FM operations. Factors that appear to have a significant impact on FM governance and management are market size and age, willingness to adapt to change, and relationships with external organizations. My findings suggest that democratic vendor engagement and documentation of procedural systems can help optimize market administration. In terms of vendor relationships, primary concerns include regulation of resellers, diplomatic vendor pool design, and creation of a collaborative atmosphere. As well, I conclude that customers are best viewed as socially invested stakeholders with a strong interest in learning about local food production. Author Keywords: farmers’ markets, global food system, local food systems, Ontario farmers’ markets, sustainability
Cytokinins in nematodes
To investigate cytokinins (CKs) in nematodes, CK profiles of a free-living Caenorhabditis elegans and a plant parasitic Heterodera glycines (soybean cyst nematode, SCN) were determined at the egg and larval stages. SCN had higher total CK level than C. elegans; however, CKs in SCN were mostly inactive precursors, whereas C. elegans had more bioactive forms. This is the first study to show that methylthiols are present in nematodes and may affect plant infection. In infectious SCN larvae, methylthiol levels were much higher than in eggs or C. elegans larvae. Furthermore, The CK profiles of SCN-susceptible and resistant Glycine max cultivars at three developmental stages revealed that, regardless of the resistance level, SCN infection caused an increase in root CKs. One resistant cultivar, Pion 93Y05, showed significantly high levels of bioactive N6-isopentenyladenine (iP) in the non-infected roots which indicated a potential role of CKs in soybean resistance to SCN. Author Keywords: Cytokinins, HPLC-MS/MS, Nematode, SCN resistance, Soybean
Potential Contribution of Mobile Processing Services to Food System Sustainability in the Regional Livestock Production Industry of Central Ontario
This qualitative study examines the applicability, impact, best practices, sustainability and livestock welfare implications of mobile processing service operation in central Ontario. Grounded theory concepts were utilized to analyze data generated from semi-structured interviews and a community focus group, supplemented by an initial exploratory literature review, and focused review approach to refine emergent categories. It was found that there is interest in, applicability for, and food system-sustainability benefit from mobile processing services, but market competition and regulatory context impede the profitability of operation, not just for mobile service, but for existing provincial plants. Public support for mobile or regionalized processing resources could address many of the sustainability concerns in our regional livestock production and consumption systems, but where appetite for such political action does not exist, solutions are required if we hope to address the continuing centralization, commodification, traditional profit-maximization and negative externality generation of our industrialized agri-food production system. Author Keywords: agri-business production and distribution, livestock welfare, mobile abattoirs and livestock processing, regional food systems, rural-urban relations, sustainability

Pages

Description

Graduate student theses produced at Trent University. You may also browse theses and dissertations by year, program, or author.

In collections

Search Our Digital Collections

Query

Enabled Filters

  • (-) ≠ Canadian studies
  • (-) = Agriculture

Filter Results

Date

2004 - 2024
(decades)
Specify date range: Show
Format: 2024/04/16

Collection

Author Name

Show more

Name (Any)

Show more

Degree

Degree Discipline

Subject (Topic)

Show more