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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Action research as a framework for systemic and organic change

Geron, Liduvino S., University of Western Sydney, Hawkesbury, Faculty of Agriculture and Rural Development January 1992 (has links)
This document outlines how organizational action was mobilized in examing and improving current organizational practices. The study was conducted in a technical task-based research organization in the Philippines and was triggered by a concern for the seeming unfavorable feedback the organization receives from the external environment. An analysis of the organizational situation showed among other factors, the apparent lack of a mechanism that relates the organization's research findings to policy making. Through action researching and using the Soft Systems Methodology as a framewrok, an action plan was developed which is designed to improve the situation. The document also discusses insights and lessons learnt in the conduct of action research. Particular focus was placed on key issues that affect individual participation and organizational actions; and how action research fares as a potential framework for organic and systemic change. From the examination of the action research experience, it became apparent that in order to fully harness the potentials of action researching, opportunities for individual participation must be well distributed and taken by the action research members. The factors affecting individual participation in group processes such as group needs, group culture and power issues in and out of the group, must likewise be addressed. This is to promote coordination, commitment and critical consciousness among group members which are essential in effecting organic and systemic change. As the research was conducted within the broad setting of agricultural research, where efforts are placed to enhance agricultural development, this document likewise discusses the potential of action research as an alternative framewrok for Research and Development (R and D) activities. It presents how action research can mobilize grassroots initiatives and actions which are crucial to a sustainable agricultural development. / Master of Science (Research) Systems Agriculture
2

IPM in Midwestern Agriculture: Implications to Pests, Pollinators, and Yield

Jacob R Pecenka (11797601) 19 December 2021 (has links)
<p>There is an existing conflict thrust upon U.S. food production systems; optimize crop yield to provide sustenance to a growing population while minimizing ecological impacts of high-intensity agriculture. This balancing act is experienced by Indiana’s watermelon growers who must maintain marketability of a crop that is reliant on insect pollinators. The dependence on pollinators to produce yield means that growers have to consider the negative impacts pesticide applications may have on both the desired pest and non-target pollinators. Navigating these trade-offs must be considered not just in the watermelon fields, but the surrounding agricultural landscape that has become increasingly reliant on prophylactic insecticides to control pests. This dissertation work results from an intensive set of experiments replicating grower practices in experimental fields throughout Indiana to assess the relationships of pests, pollinators, and crop yield.</p> Beginning with a priming year in 2017, watermelon plots were planted within larger corn fields to replicate the agriculture landscape and provide a “snapshot” of typical environment. These plots were paired at multiple locations and provided a contrast between a conventional management system that replicates grower insecticide programs with an IPM approach that removes insecticide applications outside of those based on scouting recommendations. I found that, while pest abundance and damage was higher in IPM fields, the increased pollinator visits in IPM fields led to higher yields in watermelons while corn yield was unaffected by an absence of insecticide use. Managed pollinator hives were placed in these fields and IPM resulted in the colonies exhibiting greater weight gain, lower mortality, increased reproductive growth, and higher insecticide residue accumulation. Insecticide residues were found more frequently at higher levels in the leaf tissue, crop pollen, field soil, and honey bee-collected pollen taken from CM fields. Despite these findings, there was a variable effect of the surrounding land use on the quality of collected pollen or the insecticides gathered by pollinators. These experiments demonstrate that IPM is a viable set of practices for specialty crop growers in the Midwest; successfully monitoring insect pests and conserving pollination services from both managed and wild pollinators. These findings provide a comprehensive look at the effect of IPM practices not just on the a specialty crop, but to the surrounding agricultural landscape as well. An IPM approach can be implemented by growers to decrease non-target effects from insecticides while maintaining or even improving productivity and profitability.
3

Sustainable Biochar and Charcoal Production Technologies

Francis Asare (14221814) 07 December 2022 (has links)
<p>   </p> <p>Biochar and charcoal cannot properly be discussed without understanding the diverse technologies available for their production. This is because approximately 70% of wood harvested worldwide is burned for energy and this, in addition to unstainable agricultural activities, has caused a massive increase in deforestation and contributed to climate change. Due to this, current global interventions are focused on promoting sustainable approaches through the expansion of agricultural technologies in countries where the deforestation rate keeps increasing due to overdependency on unsustainable and inefficient conversion technologies. It is therefore obvious that African regions cannot be left out when talking about the impact of global agriculture and charcoal production. Not only is 95% of all household energy used in Africa derived from burning wood in the form of charcoal and firewood, but sub-Saharan Africa regions also contribute 62% to global charcoal production. Since sustainability approaches are of global concern and must be understood from different perspectives and regions, this work analyzed sustainable agriculture and climate mitigation strategies using charcoal and biochar production as indicators. From a sustainability point of view, the study categorized this assessment into three chapters to help understand the preferences of local producers in relation to technologies used and the necessary actions or interventions needed for future improvements.</p> <p><br></p> <p>In the first chapter, 492 charcoal producers from Ghana were interviewed with semi-structured questionnaires to understand the demographics of charcoal producers, species used for charcoal, and how these producers intend to sustain the charcoal industry in terms of acquisition of wood resources/raw materials. This helped to analyze how the demographics of charcoal producers influence the charcoal production industry, characterize some wood species suitable and acceptable for sustainable charcoal production, and to recommend some necessary interventions toward sustainability.</p> <p><br></p> <p>In the second chapter, the heating characteristics of the most common indigenous species and exotic species identified in the first chapter were examined for their charcoal production properties (yield and calorific values) using the most common conversion technology available in the study area (earth mound). The heating/calorific values of these species were also determined using a ballistic bomb calorimeter. This also helped in examining the impact of the common charcoal production technologies on the qualities of charcoal produced and their corresponding impacts on the environment. Additionally, this chapter identified that most charcoal production species have longer rotation times with added values other than being used for charcoal. Furthermore, inappropriate conversion technologies minimize charcoal yield and quality; therefore, developing more efficient and affordable conversion kilns would increase charcoal production efficiency and improve the sustainable production of charcoal.</p> <p><br></p> <p>Based on the recommendation from chapter two, chapter three focused on building transferable skills and knowledge to help smallholder farmers and charcoal producers to fabricate cost-effective retorts/kilns for biochar and charcoal production. Through the process, we reviewed, selected, redesigned, and manufactured three common global conversion technologies and tested their potential for sustainable biochar and charcoal production using wood and crop stubbles (corn husk, corn cob, and sorghum residues). This helped in proposing best techniques and technologies suitable for biochar and charcoal production based on their production and use variables. It was therefore concluded that when farmers gain more knowledge and skills in manufacturing relevant and cheap technologies at their convenience, they could make the right subsequent choices towards sustainable agricultural practices.</p> <p>  </p>
4

TAXONOMIC STUDIES AND THE EVOLUTION OF HABITAT PREFERENCE IN THE CYSTOBASIDIOMYCETES

Pedro Pablo Parra Giraldo (7041446) 15 August 2019 (has links)
Pucciniomycotina is a subphylum with a high diversity in terms of habitat and life history strategies that include plant parasites, animal associates (including opportunistic human pathogens), saprobes and antagonists of other fungi. The class Cystobasidiomycetes within this subphylum is a representative of such diversity and remains understudied. Their role in nature and the associations they establish with their hosts for most of the species is still unknown. In this study we used taxonomic and phylogenetic methods to present an inventory of strains in this class collected for more than 20 years from all over the world and preserved in the Aime Lab Culture Collection. Molecular and morphological data for six new species in the genera <i>Bannoa, Buckleyzyma</i>, <i>Halobasidium</i> and <i>Sakaguchia </i>were also presented. Additionally, mating experiments were performed by pairing strains of <i>Bannoa</i>; this is the second time in the genus that clamp connections and basidia are observed. We also found that newly described species of <i>Bannoa</i> can be co-inhabitants of sori of rust fungi. In general, antagonistic interactions can occur through: 1) direct physical contact between two fungi, i.e., mycoparasitism; or, 2) the production of antimicrobial compounds. In the Cystobasidiomycetes, direct physical antagonistic interaction which is associated with sexual states has been reported in species of Cystobasidium, Naohidea, Cyphobasidium and Occultifur. On the other hand, the production of antimicrobial compounds which mainly occurs between the yeast stage of the fungi and other organisms has only been reported in Cystobasidium pallidumand Hasegawazyma lactosa. We also hypothesize that the common ancestor to Cystobasidiomycetes is a mycoparasite due to the fact that this life strategy is present in most of the lineages in the class. To test this hypothesis, we grouped into five categories the host association or substrate from which strains of extant species in the Cystobasidiomycetes were isolated, i.e.,animals, plants, fungi, aquatic or decaying organic matter. We constructed a resolved phylogeny for the class based on seven locito study the evolutionary origins of mycoparasitism through ancestral character reconstruction with representation of all described species. Our analysis suggests that the most likely hypothesis is that the most recent common ancestor of the Cystobasidiomycetes was associated to fungi.<br>
5

Challenges faced by emerging farmers in the managing projects towards sustainable agricultural development in Capricorn District, Limpopo Province, RSA

Matlou, Ntebatse Yvonne January 2018 (has links)
Thesis (M. Dev.) -- University of Limpopo, 2018 / The research investigated the challenges faced by emerging farmers in managing projects towards sustainable agricultural development in Capricorn District. The literature established the importance of project management in the context of sustainable agricultural development. In this regard, it was found that it is of extreme importance to support emerging farmers in managing agricultural projects where emerging farmers are engaged through a participatory approach in decision making processes for sustainable agricultural development. Further, this research seeks to investigate the factors that hinder project management from influencing emerging farmers to manage and sustain the agricultural projects in the area of the study. Data was collected through semi-structured interviews and questionnaires were distributed to the selected sample within the target population. The purposive sampling method was used to select the 16 project officers for interviews while questionnaires were distributed randomly for 30 emerging farmers in the Molemole and Polokwane Municipalities. The findings of the study suggest that most emerging farmers and project officers think that the lack of resources and training hamper the management and sustainability of agricultural projects. To conclude, it is expected that the recommendations will highlight strategies and policies that could be put in place to accelerate the management of agricultural projects and their sustainability in the Capricorn District.
6

Žemės ūkio reikšmė visuomenės gerovei / Agricultural value to public welfare

Stanytė, Sandra 13 June 2012 (has links)
Magistrantūros studijų baigiamasis darbas, 65 puslapiai, 16 paveikslų, 14 lentelių, 67 literatūros šaltiniai, 1 priedas, lietuvių kalba. PRASMINIAI ŽODŽIAI: visuomenės gerovė, žemės ūkis, darnus žemės ūkio vystymasis, žemės ūkio daugiafunkciškumas. Tyrimo objektas – žemės ūkio reikšmė visuomenės gerovei. Tyrimo tikslas – atskleidus žemės ūkio reikšmės ir poveikio visuomenės gerovei vertinimo problematiką, įvertinti žemės ūkio reikšmę visuomenės gerovei. Uždaviniai: 1) atskleisti žemės ūkio poveikio visuomenės gerovei vertinimo galimybes, remiantis žemės ūkio daugiafunkciškumo ir darnaus žemės ūkio vystymosi koncepcijomis; 2) pagrįsti žemės ūkio vaidmens ir jo reikšmės visuomenės gerovei vertinimą per ekonominę, socialinę ir aplinkosauginę dimensijas; 3) įvertinti žemės ūkio reikšmę visuomenės gerovei Lietuvoje per socialinę, ekonominę ir aplinkosauginę dimensijas. Tyrimo metodai: mokslinės literatūros loginės analizės ir sintezės, statistinių duomenų analizės, grafinis vaizdavimo būdas. Tyrimo rezultatai: • pirmojoje darbo dalyje pateikti žemės ūkio reikšmės visuomenės gerovei socialiniai, ekonominiai, aplinkosaugos aspektai. Pateiktas įvairių organizacijų ir mokslininkų, tyrėjų požiūris į žemės ūkio reikšmę visuomenės gerovei; • antrojoje darbo dalyje identifikuoti rodikliai, naudojami vertinant žemės ūkio reikšmę visuomenės gerovei; • trečiojoje darbo dalyje įvertinta Lietuvos žemės ūkio reikšmė visuomenės gerovei per ekonominę, socialinę ir aplinkosauginę dimensijas... [toliau žr. visą tekstą] / The final work of University Postgraduate studies, 65 pages, 16 pictures, 14 tables, 67 referencies, 1 annex, Lithuanian language. KEY WORDS: public welfare, agriculture, sustainable agricultural development, multifunctionality of agriculture. Research object: agricultural value to public welfare. Research aim: assess agricultural value to public welfare. Objectives: 1) to reveal assessment possibilities of the effects of agriculture on public welfare based on multifunctionality of agriculture and sustainable agriculture development; 2) to reason the assessment of agriculture and its importance to public welfare through the economic, social and environmental dimensions; 3) to asssess the significance of the agricultural value to public welfare in Lithuania by social, economic and environmental dimensions. Research methods: logical analysis and synthesis of scientific literature, visualization, statistical data analysis. Study results: • The first part presents social, economic and environmental aspects of the agricultural value, describes the approach of organizations, scientists and researchers to agricultural value to the public welfare; • The second part of the paper presents indicators that are used to assess the agricultural value to public welfare; • The third part assess Lithuanian value of the agriculture to public welfare through economic, social and environmental dimensions. Due to the multiplicity of the public welfare and abudance of agricultural functions... [to full text]
7

Human-in-the-loop of Cyber Physical Agricultural Robotic Systems

Maitreya Sreeram (9706730) 15 December 2020 (has links)
The onset of Industry 4.0 has provided considerable benefits to Intelligent Cyber-Physical Systems (ICPS), with technologies such as internet of things, wireless sensing, cognitive computing and artificial intelligence to improve automation and control. However, with increasing automation, the “human” element in industrial systems is often overlooked for the sake of standardization. While automation aims to redirect the workload of human to standardized and programmable entities, humans possess qualities such as cognitive awareness, perception and intuition which cannot be automated (or programmatically replicated) but can provide automated systems with much needed robustness and sustainability, especially in unstructured and dynamic environments. Incorporating tangible human skills and knowledge within industrial environments is an essential function of “Human-in-the-loop” (HITL) Systems, a term for systems powerfully augmented by different qualities of human agents. The primary challenge, however, lies in the realistic modelling and application of these qualities; an accurate human model must be developed, integrated and tested within different cyber-physical workflows to 1) validate the assumed advantages, investments and 2) ensure optimized collaboration between entities. Agricultural Robotic Systems (ARS) are an example of such cyber-physical systems (CPS) which, in order to reduce reliance on traditional human-intensive approaches, leverage sensor networks, autonomous robotics and vision systems and for the early detection of diseases in greenhouse plants. Complete elimination of humans from such environments can prove sub-optimal given that greenhouses present a host of dynamic conditions and interactions which cannot be explicitly defined or managed automatically. Supported by efficient algorithms for sampling, routing and search, HITL augmentation into ARS can provide improved detection capabilities, system performance and stability, while also reducing the workload of humans as compared to traditional methods. This research thus studies the modelling and integration of humans into the loop of ARS, using simulation techniques and employing intelligent protocols for optimized interactions. Human qualities are modelled in human “classes” within an event-based, discrete time simulation developed in Python. A logic controller based on collaborative intelligence (HUB-CI) efficiently dictates workflow logic, owing to the multi-agent and multi-algorithm nature of the system. Two integration hierarchies are simulated to study different types of integrations of HITL: Sequential, and Shared Integration. System performance metrics such as costs, number of tasks and classification accuracy are measured and compared for different collaboration protocols within each hierarchy, to verify the impact of chosen sampling and search algorithms. The experiments performed show the statistically significant advantages of HUB-CI based protocol over traditional protocols in terms of collaborative task performance and disease detectability, thus justifying added investment due to the inclusion of HITL. The results also discuss the competitive factors between both integrations, laying out the relative advantages and disadvantages and the scope for further research. Improving human modelling and expanding the range of human activities within the loop can help to improve the practicality and accuracy of the simulation in replicating an HITL-ARS. Finally, the research also discusses the development of a user-interface software based on ARS methodologies to test the system in the real-world.<br>
8

Role of Fungal and Host-Associated Volatiles in the Chemical Ecology of Scolytine Beetles Affecting Hardwood Trees

Matthew W Ethington (10731882) 30 April 2021 (has links)
<div>Native and invasive bark and ambrosia beetles threaten the health and productivity of natural and planted forests worldwide. Management of these pests relies on semiochemical-based tactics, but these are often ineffective at monitoring for incipient populations or decreasing pest populations. The role of fungal and non-host volatiles in colonization behavior remains unknown for many important bark and ambrosia beetle species, thereby hindering their control. In this dissertation, I tested the hypothesis that fungal and tree-associated volatiles influence the host colonization behavior of bark and ambrosia beetles that affect hardwood trees. This work describes the identification of novel fungal and host-associated semiochemicals that may aid in future management of these important pests.</div><div><br></div><div>In Chapter 1, I review the current literature describing the volatile chemical ecology of bark and ambrosia beetles that inhabit hardwood trees. A review of groups with numerous identified semiochemicals, as well as considerations for future research is included.</div><div><br></div><div>In Chapter 2, I test the hypothesis that host colonization by the peach bark beetle (Phloeotribus liminaris) is chemically mediated by compounds associated with infested hosts. I found that benzaldehyde mediates colonization by the peach bark beetle, and that that benzaldehyde lures are effective attractants in field-trapping studies.</div><div><br></div><div>In Chapter 3, I test the hypothesis that ambrosia beetle attraction to host stress compounds can be modified by symbiotic fungal volatiles. I found that for three species of invasive ambrosia beetles individual fungal volatiles act as repellents, with species-specific differences in response to different compounds.</div><div><br></div><div>In Chapter 4, I test the hypothesis that attraction of the walnut twig beetle (Pityophthorus juglandis) to its pheromone lure can be enhanced by symbiotic fungal volatiles. I found that symbiotic fungal volatiles consistently enhance attraction of the beetles to their fungus, while one symbiotic fungal volatile of ambrosia beetle species repelled the walnut twig beetle.</div><div><br></div><div>In Chapter 5, I summarize results from each of the chapters and discuss patterns observed in the response to fungal and host-associated volatiles among the focal bark and ambrosia beetle species. I also discuss future research needs and directions to continue development of the knowledge surrounding scolytine chemical ecology and management of these pest beetle species.</div>
9

Multiple Tactics to Improve our Understanding of Soybean Diseases

Mariama Tricuonia Brown (15295693) 14 April 2023 (has links)
<p>  </p> <p>Sudden death syndrome (SDS) caused by <em>Fusarium virguliforme</em> is one of the top yield-reducing diseases of soybean. This disease results in a two-stage symptom development, root rot followed by foliar interveinal chlorosis and necrosis. Foliar symptoms typically appear late in the growing season [full pod to full seed (R4 to R6) reproductive growth stages]. Prior to foliar symptoms, a destructive technique is usually carried out to identify the root rot phase of SDS. This technique requires intensive crop scouting and an expert for accurate diagnosis. Therefore, a nondestructive technique is needed to diagnose SDS disease in the absence of visible foliar symptoms. Additionally, no soybean cultivar is completely resistant to SDS and no single method can completely manage this disease. So, an improved integrated approach is needed for SDS disease management. </p> <p>Foliar fungal diseases such as frogeye leaf spot (<em>Cercospora sojina</em> Hara), Septoria brown spot (<em>Septoria glycines</em> Hemmi), and Cercospora leaf blight (<em>Cercospora</em> spp.) are also economically important diseases of soybean. To limit the losses caused by these diseases, several management methods can be used including the application of foliar fungicide. However, due to the low foliar disease pressure that is observed most years, fungicide applications may not be warranted to be applied annually in Indiana. </p> <p>The objectives of this research were: 1) to assess the effectiveness and economic impact of integrated management strategies that include cultivar selection, seed treatment, and seeding rate on SDS in Indiana; 2) to pre-symptomatically and non-destructively detect SDS disease using hyperspectral measurements; and 3) to evaluate foliar fungicides on soybean foliar diseases and yield in Indiana. </p> <p>Results from this research support the use of a seed treatment to protect soybean roots from SDS infection and the use of a moderately resistant cultivar planted at a seeding rate of 346,535 seeds/ha to protect yield and maximize on net returns. This research also demonstrated the ability of hyperspectral reflectance to discriminate healthy from <em>F. virguliforme</em> infected soybean roots in the absence of foliar symptoms. In addition, results show that fungicide applications can reduce foliar disease over the nontreated control, but under low foliar disease risk, these fungicides did not significantly increase yield over the nontreated control. Altogether, these results will contribute to improved soybean disease management approaches in Indiana.</p>
10

PRODUCTION AND NUTRITION RECOVERY OF CROPS IN A RECIRCULATING AQUAPONIC SYSTEMS

Teng Yang (7037720) 16 August 2019 (has links)
<div>The goal of this research was to improve crop yield and quality and enhance nutrient use efficiency of aquaponics for the development of sustainable aquaponic production system. Aquaponics is the integration of aquaculture and hydroponics by recirculating water and residual nutrients resulting from aquaculture wastewater into hydroponic crop production. The project had four objectives. The first objective was to characterize nutrient composition and accumulation in recirculating water and plant parts of tomato, basil, and lettuce grown in aquaponic systems, and to compare their growth and yield with those grown in hydroponic systems. The second objective was to determine the effects of feeding management regime on water quality, crop yield and quality, and N use efficiency for vegetable and herb production in recirculating aquaponics in comparison to hydroponics. The third objective was to optimize water-flow rate for efficient aquaponic system for maximum crop yield. The fourth objective was to investigate and compare the N and P mass balance between aquaponics and hydroponics. Four conclusions were determined that 1) Aquaponic solution was deficient in Ca and/or Mg leading to plant nutrient deficiency but sufficient or high in P; And luxuriant nutrient profiles in hydroponics are not necessary to enhance crop yield in aquaponics as long as key factors affecting crop yield are identified and properly addressed. 2) Uniform feeding regime improved water quality by reducing toxic ions and enhancing initial nutrient availability and considerably increased the yield, quality and nitrogen use efficiency (NUE) of crops in aquaponics as close or similar to those in hydroponics. 3) Flow rate is an important factor affecting water quality parameters and optimizing flow rate is essential to maximize aquaponic crop production and improve energy efficiency; High hydraulic loading rate at 3.3 m3/m2-day improved performance and yield of all crops in an aquaponics system regardless of their growth rate, but the water hydraulic loading rate for fast-growing and medium-growing crops can be reduced to 2.2 m3/m2-day without production reduction. 4) Plant species had significant influence on N and P removal and mass balance in aquaponics and hydroponics; Fruity vegetables showed better growth adaption in aquaponic system, while yields of leafy vegetables may be reduced when grown in aquaponics than hydroponics; Aquaponics is more efficient than hydroponics releasing less environmental wastes, however, N and P use efficiency in aquaponics and hydroponics can be further improved via proper management.</div><div>The important findings obtained from this research will fill the knowledge gap in aquaponic research and provide new management strategies to improve quantitative study of aquaponic crop production and new management strategies for cultivating crops in aquaponics. The findings will also greatly contribute to the commercial aquaponic development, and ultimately improve food security and resource use efficiency in the US and global agricultural production.</div>

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