The research focuses on sustainable development at the community level in Sweden. Following the trend of sustainable development, the concept of distributed energy has emerged in the European Union. Authorities at all levels in Sweden have also actively promoted the deployment of distributed energy projects. Thereby the sustainable development of community-level has begun to flourish. The study selects five relatively mature sustainability cases to explore sustainable development at the community level in Sweden. Three cases are from Sweden, and the remaining two comparative cases are from Germany and Denmark. Based on qualitative research and case study, the thesis studies the implementation of relevant cases. It analyzes the differences and related challenges between the three Swedish communities and the German/Danish case regarding sustainable development. The study shows that all community cases have set the energy transition in the transportation sector as a priority in the plan. While paying attention to the energy transition, the three Swedish communities also pay more attention to the improvement of social equality and welfare in sustainability. Therefore, compared to the cases in the other two countries, the sustainable development of the three Swedish communities seems to be more balanced. However, whether for the three Swedish communities or the German/Danish case, there are still many challenges to realize the integration of sustainability strategies into community development.

In lifetime risk for Human Immunodeficiency Virus (HIV), Black men who have sex with men (BMSM) are at the greatest risk of all demographic groups. Creative modes of engagement have been established to reach this group in prevention efforts, including prevention programming in community-based organizations such as churches. Church-based HIV prevention is an emerging area of research and existing studies fall into one of three categories: BMSM’s perspectives on church and church-based HIV prevention, church leaders’ and members’ perspectives on HIV prevention in their congregations, and reported outcomes of HIV prevention interventions that have been conducted in church settings. Given the paucity of research in this area, a scoping analysis was conducted to survey the existing studies in order to identify overarching themes and gaps for future research efforts. In a review of the research, facilitators and barriers to successful implementation of HIV programming in churches emerged. Prominent barriers were stigmatizing sermons given in church and pastoral denial that HIV is a relevant issue to the Black community. Facilitators reported commonly were BMSM’s comfort found in faith and a pastor’s blessing of HIV prevention efforts in churches. Interventions primarily reported lessons learned in implementation of church-based HIV programs. A frequently reported lesson learned was the importance of close collaboration with participant churches to develop program curricula that were effectively couched within church doctrine, and that would be received well by church members. Some interventions also measured intervention efficacy outcomes, one of which showed a statistically significant decrease in HIV stigma post-intervention. This research has important implications for the effective development, implementation, and reporting of outcomes for future, church-based HIV interventions. As research in HIV prevention in the church continues to develop, it may be able to serve as a template for other community-based HIV prevention efforts and open doors for inclusion of other high risk groups such as injection drug users and sex workers.

China’s rapid urbanization and mass migration over the past several decades has resulted in approximately 69 million children being left-behind in the countryside. Many of these children suffer from problems linked to a lack of parental care and emotional support, including physical and psychological abuse, neglect, truancy, and even malnutrition. In 2010, the Chinese Ministry of Civil Affairs and UNICEF piloted a “child welfare director (CWD)” model in Chinese 120 hinterland villages aimed at empowering community members to fill the gaps in child welfare provision and to improve the well-being of disadvantaged children in rural areas. Since 2019 the Chinese government has strived to implement the CWD system across the country. Informed by a theoretical framework that encompasses the concepts of child development, family support, and child welfare models in China and Japan, this study investigates the implementation and further development of the CWD system. A comparative analysis of the Japanese commissioned welfare volunteer and chief child welfare volunteer system is also utilized to explore possible lessons for the Chinese circumstances. The research findings highlight the crucial coordination function of the CWD system in incorporating families, schools, government bureaus, and various social sectors into a synergetic network to connect fragmented child welfare resources and services to support disadvantaged children and families. Analysis of the Japanese approach sheds light on the further development of the CWD system in terms of consolidating the partnership between CWDs and schools, promoting the cooperation between CWDs and social welfare institutions, as well as strengthening the professionalism of CWDs. This research also examines the involvement of civil society in child welfare provision in contemporary China. For program planners and policymakers, this thesis emphasizes the central role of governments at various levels, along with the important though limited contributions of non-government sectors, in providing more financial, human, and training resources to support the implementation of the CWD system to enhance child welfare provision in rural China. A key recommendation arising from this research is to establish a new specially designated government department with responsibility for all relevant child welfare issues. The thesis also speaks to the wider issue of promoting rural revitalization and rural-urban integration to address the specific challenges of left-behind children in the Chinese countryside. / Graduate

The chemical and physical processes controlling contaminant fate and transport in the vadose zone limit the options for application of many remedial technologies. Foam delivery technology (FDT) has been developed as a potential solution to overcome these limitations for remediating subsurface and deep vadose zone environments using reactive amendments. Although there are many advantages to utilizing FDT for treatment in the deep vadose zone, little information is available on how the addition of these surfactants and remedial amendments affect the indigenous microbial communities in the deep vadose zone as well as the impact of biological transformations of surfactant-based foams on remediation efforts. The purpose of this study was to develop a rapid method for assessment of microbial communities in contaminated subsurface environments. This research was divided into two phases: (1) assess the toxicity of proposed FDT components on a single bacterial species, Shewanella oneidensis MR-1; and (2) determine the effects of these components on a microbial community from the vadose zone. In Phase I, S. oneidensis MR-1 was exposed to proposed FDT components to assess potential growth inhibition or stimulation caused by these chemicals. S. oneidensis MR-1 cultures were exposed to the surfactants sodium laureth sulfate (SLES), sodium dodecyl sulfate (SDS), cocamidopropyl betaine (CAPB), and NINOL 40-CO, and the remedial amendment, calcium polysulfide (CPS). Results from this phase revealed that the relative acute toxicity order for these compounds was SDS>>CPS>>NINOL40-CO>SLES≥CAPB. High concentrations of SDS were toxic to the growth of S. oneidensis MR-1 but low concentrations were stimulatory. This benchtop system provided a capability to assess adverse microbial-remediation responses and contributed to the development of in situ remedial chemistries before they are deployed in the field. For Phase II, sediments from the BC Cribs and Trenches (BCCT) area of the Hanford Site, WA, were characterized before and after exposure to potential FDT components. First, the phylogenetic and metabolic diversity of sediment from the BCCT was assessed by sequencing the microbial community and measuring the metabolic activity. The sediment was also incubated with various concentrations of SDS, CAPB, and CPS. Phylogenetic analysis detected phylotypes from the Alpha-, Beta-, Delta-, and Gammaproteobacteria, and Actinobacteria. Unlike the S. oneidensis MR-1 studies conducted in Phase I, the surfactants and CPS stimulated the metabolic activity of the native microbial communities. The observed stimulation could be caused by sorption of the chemicals to the sediment particles, or utilization of the surfactants by the microbial communities. These findings emphasize the importance of monitoring microbial activity at remediation sites in order to determine short and long term efficacy of the treatment, compliance with regulatory mandates, and act as an early warning indicator of unintended changes to the subsurface.

This dissertation presents the design and case study application of a participatory decision-making support tool for appropriate safe water systems development in marginalized low-income communities of the global South. The tool focuses on the resolution of two key design decisions: 1) selecting the appropriate level of application (i.e. household or community level) for a safe water system; and 2) selecting an appropriate water treatment technology (or technologies). The tool breaks the process down into four stages. First are pre-implementation steps which develop a contextualized, baseline understanding of the local community. Second is community-based field research, including focus groups and key informant/informal interviews, to investigate the two key design questions by exploring local preferences, capacities, and circumstances with community-members, government officers, NGO workers, and other stakeholders. Third are analytical steps to integrate information from baseline, informal, and primary research to generate recommendations on the two key design questions. This includes a comparative analysis of household and community level systems; a technology feasibility flowchart; performance assessments of technological alternatives with respect to appropriate technology criteria; and a multi-factor analysis to integrate information from the preceding analytical steps. Fourth are community forums in which further participatory action and research is planned on the basis of the recommendations emerging from the tool. Through these steps, the decision-making support tool guides implementing organizations through the stages of safe water systems design and planning in a manner that centres local people in the process. The tool weaves together several theoretical and methodological strands including humanitarian engineering, post-normal science, appropriate technology, participatory development, grounded theory, engineering decision-making, and water treatment engineering. The case study application of the decision-making support tool was conducted in a marginalized peri-urban community called Mylai Balaji Nagar in Chennai, India. This indicated that a household level approach is more appropriate for the case study community and that the TATA Swach filter, alum coagulation with chlorination, or boiling, in order of decreasing suitability, may be appropriate technologies for household application in the case study community. / Degree: Doctor of Philosophy Department: School of Engineering Advisor: Hall, Kevin / International Development Research Centre (IDRC)

Background : Studies of self-rated oral health are always done at either the individual level or the aggregate level. Partitioning individual and neighbourhood sources of variation also enables explorations of the influences of people’s social context on their self-rated oral health. Objective : The main objective of the study was to examine the influence of the social context in which people live on their self-rating of their oral health, independent of individual indicators of good oral health. Method : This study used a secondary analysis of data on a nationally representative sample of 2 907 South African adults (aged ≥ 16 years) who had participated in the 2007 annual South African Social Attitude Survey (SASAS). The 2007 SASAS used a multi-stage probability sampling strategy, with census enumeration areas as the primary sampling unit. Using an interviewer-administered questionnaire, the information obtained included socio-demographic data, the respondents’ level of trust in people (a proxy measure for social capital), oral health behaviours and self-rated oral health. Using the 2005 General Household Survey (GHS) (persons’ n=107 987; households’ n=28 129), the living environment characteristics of participants of the SASAS were obtained, including sources of water and energy supply and household cell phone ownership as a proxy measure for social networking. A mixed-effects model was then constructed to determine factors associated with a self-rating of oral health as ‘very good/good’. Results : Of the respondents, 51.7% were female. Among the respondents, 76.3% self-rated their oral health as good. There was a significant gender modifying effect, thus analyses was stratified by gender. The odds of self-rating oral health as good was significantly higher only among females living in areas with higher household cell phone ownership density, even after controlling for potential confounders. At the individual level, trust was positively associated with good self-rated oral health only among males, and higher social ranking in the society was positively associated with good self-rated oral health only among females. Overall, 55% of the total variance in self-rated oral health was explained by factors operating at the individual level, whereas 18% of the total variance was explained by factors operating at the community level. Self-report of recent oral health problems such as toothache and oral malodour were significantly associated with lower odds of self-rating their oral health as good, as was with reporting less frequent brushing. Conclusion : Good self-rated oral health may be positively associated with indicators of higher levels of social capital both at the level of the individual and the community and with less physical impairments of oral functioning. Furthermore, the findings indicate that unlike men’s oral health ratings, women’s oral health ratings are more likely to be influenced by women’s social relationships with others in the society. Copyright / Dissertation (MSc)--University of Pretoria, 2011. / School of Health Systems and Public Health (SHSPH) / Unrestricted

Research on intimate partner violence (IPV) and intimate partner sexual violence (IPSV) has largely focused on individual and dyadic-level risk factors, but recently studies have explored how the surrounding environment is associated with IPV/IPSV. Studies that have explored community-level variables typically only use IPV/IPSV samples and do not first compare indicators of IPV/IPSV to those of general crime in those same communities. To address these gaps, this study was conducted in two parts. Data were retrieved from the Tennessee Bureau of Investigation Reporting System, County Health Rankings and Roadmaps System, the US Census Bureau, and other sources. Study 1 first determined that aspects of gender inequality, specific socioeconomic variables, and health-related factors differentiated IPV/IPSV from community crime. Study 2 utilized multilevel modeling to further investigate the nested effects of IPV/IPSV on individuals within the larger community. Significant individual level variables included younger age, differences among relationship type, and drug use. At the community level, factors related to socioeconomics and children, firearm prevalence, and certain health-related factors (e.g., lack of health insurance) were important when comparing IPV/IPSV. Prevention and intervention efforts should improve healthcare access and medical IPV screening, target younger age groups, provide specific resources to improve socioeconomic status, and reduce excessive drug/alcohol use and firearm use in IPV/IPSV.

Take-all is the name given to the disease caused by a soilborne fungus Gaeumannomyces graminis (Sacc.) von Arx and Olivier var. tritici Walker (Ggt), an ascomycete of the family Magnaportheaceae (Cook, 2003). This fungus is an aggressive soil-borne pathogen causing root rot of wheat (primary host), barley and rye crops (secondary host). The flowering, seedling, and vegetative growth stages can be affected by the infection of the whole plant, leaves, roots, and stems. Infections of roots result in losses in crop yield and quality primarily due to a lowering in nutrient uptake. Take-all is most common in regions where wheat is cultivated without adequate crop rotation. Crop rotation allows time between the planting dates of susceptible crops, which causes a decrease in the inoculum potential of soilborne plant pathogens to levels below an economic threshold by resident antagonistic soil microbial communities. Soilborne disease suppressiveness is an inherent characteristic of the physical, chemical, and/or biological structure of a particular soil which might be induced by agricultural practices and activities such as the cultivation of crops, or the addition of organisms or nutritional amendments, causing a change in the microfloral environment. Disturbances of soil ecosystems that impact on the normal functioning of microbial communities are potentially detrimental to soil formation, energy transfers, nutrient cycling, and long-term stability. In this regard, an overview of soil properties and processes indicated that the use of microbiological and biochemical soil properties, such as microbial biomass, the analysis of microbial functional diversity and microbial structural diversity by the quantification of community level physiological profiles and signature lipid biomarkers are useful as indicators of soil ecological stress or restoration properties because they are more responsive to small changes than physical and chemical characteristics. In this study, the relationship between physico-chemical characteristics, and different biological indicators of soil quality of agricultural soils conducive, suppressive, and neutral with respect to take-all disease of wheat as caused by the soilborne fungus Gaeumannomyces graminis var. tritici (Ggt), were investigated using various techniques. The effect of crop rotation on the functional and structural diversity of soils conducive to take-all disease was also investigated. Through the integration of quantitative and qualitative biological data as well as the physico-chemical characteristics of the various soils, the functional and structural diversity of microbial IV communities in the soils during different stadia of take-all disease of wheat were characterised. All results were evaluated statistically and the predominant physical and chemical characteristics that influenced the microbiological and biochemical properties of the agricultural soils during different stadia of take-all disease of wheat were identified using multivariate analyses. Although no significant difference @ > 0.05) could be observed between the various soils using conventional microbiological enumeration techniques, the incidence of Gliocladium spp. in suppressive soils was increased. Significant differences @ < 0.05) were observed between agricultural soils during different stadia of take-all disease of wheat. Although no clear distinction could be made between soils suppressive and neutral to take-all disease of wheat, soils suppressive and conducive to take-all disease of wheat differed substantially in their community level physiological profiles (CLPPs). Soils suppressive / neutral to take-all disease were characterised by enhanced utilisation of carboxylic acids, amino acids, and carbohydrates, while conducive soils were characterised by enhanced utilisation of carbohydrates. Shifts in the functional diversity of the associated microbial communities were possibly caused by the presence of Ggt and associated antagonistic fungal and bacterial populations in the various soils. It was evident that the relationships amongst the functionality of the microbial communities within the various soils had undergone changes through the different stages of development of take-all disease of wheat, thus implying different substrate utilisation capabilities of present soil microbial communities. Diversity indices were calculated as Shannon's diversity index (H') and substrate equitability (J) and were overall within the higher diversity range of 3.6 and 0.8, respectively, indicating the achievement of very high substrate diversity values in the various soils. A substantial percentage of the carbon sources were utilised, which contributed to the very high Shannon-Weaver substrate utilisation indices. Obtained substrate evenness (equitability) (J) indices indicated an existing high functional diversity. The functional diversity as observed during crop rotation, differed significantly (p < 0.05) from each other, implying different substrate utilisation capabilities of present soil microbial communities, which could possibly be ascribed to the excretion of root exudates by sunflowers and soybeans. Using the Sorenson's index, a clear distinction could be made between the degrees of substrate utilisation between microbial populations in soils conducive, suppressive, and neutral to take-all disease of wheat, as well as during crop rotation. Furthermore, the various soils could also be differentiated on the basis of the microbial community structure as determined by phospholipid fatty acid (PLFA) analysis. Soil suppressive to take-all disease of wheat differed significantly (p < 0.05) from soils conducive, and neutral to take-all disease of wheat, implying a shift in relationships amongst the structural diversity of microbial communities within the various soils. A positive association was observed between the microbial phospholipid fatty acid profiles, and dominant environmental variables of soils conducive, suppressive, and neutral to take-all disease of wheat. Soils conducive and neutral to take-all disease of wheat were characterised by high concentrations of manganese, as well as elevated concentrations of monounsaturated fatty acids, terminally branched saturated fatty acids, and polyunsaturated fatty acids which were indicative of Gram-negative bacteria, Gram-positive bacteria and micro eukaryotes (primarily fungi), respectively. These soils were also characterised by low concentrations of phosphorous, potassium, percentage organic carbon, and percentage organic nitrogen, as well as low soil pH. Soil suppressive to take-all disease of wheat was characterised by the elevated levels of estimated of biomass and elevated concentrations of normal saturated fatty acids, which is ubiquitous to micro-organisms. The concentration of normal saturated fatty acids in suppressive soils is indicative of a low structural diversity. This soil was also characterised by high concentrations of phosphorous, potassium, percentage organic carbon, and percentage organic nitrogen, as well as elevated soil pH. The relationship between PLFAs and agricultural soils was investigated using principal component analysis (PCA), redundancy analysis (RDA) and discriminant analysis (DA). Soil suppressive to take-all disease of wheat differed significantly (p < 0.05) from soils conducive, and neutral to take-all disease of wheat, implying a shift in relationships amongst the structural diversity of microbial communities within the various soils. A positive association was observed between the microbial phospholipid fatty acid profiles, and dominant environmental variables of soils conducive, suppressive, and neutral to take-all disease of wheat. Hierarchical cluster analysis of the major phospholipid fatty acid groups indicated that the structural diversity differed significantly between soils conducive, suppressive, and neutral to take-all disease of wheat caused by Gaeumannomyces graminis var. tritici. The results indicate that the microbial community functionality as well as the microbial community structure was significantly influenced by the presence of take-all disease of wheat caused by Gaeumannomyces graminis var. tritici, and that the characterisation of microbial functional and structural diversity by analysis of community level physiological profiles and phospholipid fatty acid analysis, respectively, could be successfully used as an assessment criteria for the evaluation of agricultural soils conducive, suppressive, and neutral to take-all disease of wheat, as well as in crop rotation systems. This methodology might be of significant value in assisting in the management and evaluation of agricultural soils subject to the prevalence of other soilborne diseases. / Thesis (M.Sc. (Microbiology))--North-West University, Potchefstroom Campus, 2004.

Take-all is the name given to the disease caused by a soilborne fungus Gaeumannomyces graminis (Sacc.) von Arx and Olivier var. tritici Walker (Ggt), an ascomycete of the family Magnaportheaceae (Cook, 2003). This fungus is an aggressive soil-borne pathogen causing root rot of wheat (primary host), barley and rye crops (secondary host). The flowering, seedling, and vegetative growth stages can be affected by the infection of the whole plant, leaves, roots, and stems. Infections of roots result in losses in crop yield and quality primarily due to a lowering in nutrient uptake. Take-all is most common in regions where wheat is cultivated without adequate crop rotation. Crop rotation allows time between the planting dates of susceptible crops, which causes a decrease in the inoculum potential of soilborne plant pathogens to levels below an economic threshold by resident antagonistic soil microbial communities. Soilborne disease suppressiveness is an inherent characteristic of the physical, chemical, and/or biological structure of a particular soil which might be induced by agricultural practices and activities such as the cultivation of crops, or the addition of organisms or nutritional amendments, causing a change in the microfloral environment. Disturbances of soil ecosystems that impact on the normal functioning of microbial communities are potentially detrimental to soil formation, energy transfers, nutrient cycling, and long-term stability. In this regard, an overview of soil properties and processes indicated that the use of microbiological and biochemical soil properties, such as microbial biomass, the analysis of microbial functional diversity and microbial structural diversity by the quantification of community level physiological profiles and signature lipid biomarkers are useful as indicators of soil ecological stress or restoration properties because they are more responsive to small changes than physical and chemical characteristics. In this study, the relationship between physico-chemical characteristics, and different biological indicators of soil quality of agricultural soils conducive, suppressive, and neutral with respect to take-all disease of wheat as caused by the soilborne fungus Gaeumannomyces graminis var. tritici (Ggt), were investigated using various techniques. The effect of crop rotation on the functional and structural diversity of soils conducive to take-all disease was also investigated. Through the integration of quantitative and qualitative biological data as well as the physico-chemical characteristics of the various soils, the functional and structural diversity of microbial IV communities in the soils during different stadia of take-all disease of wheat were characterised. All results were evaluated statistically and the predominant physical and chemical characteristics that influenced the microbiological and biochemical properties of the agricultural soils during different stadia of take-all disease of wheat were identified using multivariate analyses. Although no significant difference @ > 0.05) could be observed between the various soils using conventional microbiological enumeration techniques, the incidence of Gliocladium spp. in suppressive soils was increased. Significant differences @ < 0.05) were observed between agricultural soils during different stadia of take-all disease of wheat. Although no clear distinction could be made between soils suppressive and neutral to take-all disease of wheat, soils suppressive and conducive to take-all disease of wheat differed substantially in their community level physiological profiles (CLPPs). Soils suppressive / neutral to take-all disease were characterised by enhanced utilisation of carboxylic acids, amino acids, and carbohydrates, while conducive soils were characterised by enhanced utilisation of carbohydrates. Shifts in the functional diversity of the associated microbial communities were possibly caused by the presence of Ggt and associated antagonistic fungal and bacterial populations in the various soils. It was evident that the relationships amongst the functionality of the microbial communities within the various soils had undergone changes through the different stages of development of take-all disease of wheat, thus implying different substrate utilisation capabilities of present soil microbial communities. Diversity indices were calculated as Shannon's diversity index (H') and substrate equitability (J) and were overall within the higher diversity range of 3.6 and 0.8, respectively, indicating the achievement of very high substrate diversity values in the various soils. A substantial percentage of the carbon sources were utilised, which contributed to the very high Shannon-Weaver substrate utilisation indices. Obtained substrate evenness (equitability) (J) indices indicated an existing high functional diversity. The functional diversity as observed during crop rotation, differed significantly (p < 0.05) from each other, implying different substrate utilisation capabilities of present soil microbial communities, which could possibly be ascribed to the excretion of root exudates by sunflowers and soybeans. Using the Sorenson's index, a clear distinction could be made between the degrees of substrate utilisation between microbial populations in soils conducive, suppressive, and neutral to take-all disease of wheat, as well as during crop rotation. Furthermore, the various soils could also be differentiated on the basis of the microbial community structure as determined by phospholipid fatty acid (PLFA) analysis. Soil suppressive to take-all disease of wheat differed significantly (p < 0.05) from soils conducive, and neutral to take-all disease of wheat, implying a shift in relationships amongst the structural diversity of microbial communities within the various soils. A positive association was observed between the microbial phospholipid fatty acid profiles, and dominant environmental variables of soils conducive, suppressive, and neutral to take-all disease of wheat. Soils conducive and neutral to take-all disease of wheat were characterised by high concentrations of manganese, as well as elevated concentrations of monounsaturated fatty acids, terminally branched saturated fatty acids, and polyunsaturated fatty acids which were indicative of Gram-negative bacteria, Gram-positive bacteria and micro eukaryotes (primarily fungi), respectively. These soils were also characterised by low concentrations of phosphorous, potassium, percentage organic carbon, and percentage organic nitrogen, as well as low soil pH. Soil suppressive to take-all disease of wheat was characterised by the elevated levels of estimated of biomass and elevated concentrations of normal saturated fatty acids, which is ubiquitous to micro-organisms. The concentration of normal saturated fatty acids in suppressive soils is indicative of a low structural diversity. This soil was also characterised by high concentrations of phosphorous, potassium, percentage organic carbon, and percentage organic nitrogen, as well as elevated soil pH. The relationship between PLFAs and agricultural soils was investigated using principal component analysis (PCA), redundancy analysis (RDA) and discriminant analysis (DA). Soil suppressive to take-all disease of wheat differed significantly (p < 0.05) from soils conducive, and neutral to take-all disease of wheat, implying a shift in relationships amongst the structural diversity of microbial communities within the various soils. A positive association was observed between the microbial phospholipid fatty acid profiles, and dominant environmental variables of soils conducive, suppressive, and neutral to take-all disease of wheat. Hierarchical cluster analysis of the major phospholipid fatty acid groups indicated that the structural diversity differed significantly between soils conducive, suppressive, and neutral to take-all disease of wheat caused by Gaeumannomyces graminis var. tritici. The results indicate that the microbial community functionality as well as the microbial community structure was significantly influenced by the presence of take-all disease of wheat caused by Gaeumannomyces graminis var. tritici, and that the characterisation of microbial functional and structural diversity by analysis of community level physiological profiles and phospholipid fatty acid analysis, respectively, could be successfully used as an assessment criteria for the evaluation of agricultural soils conducive, suppressive, and neutral to take-all disease of wheat, as well as in crop rotation systems. This methodology might be of significant value in assisting in the management and evaluation of agricultural soils subject to the prevalence of other soilborne diseases. / Thesis (M.Sc. (Microbiology))--North-West University, Potchefstroom Campus, 2004.

The objective of this work was to understand microbial population density and diversity, both spatially and temporally, in wetland mesocosms to gain a better fundamental understanding for use in the optimization and design of constructed wetlands (CWs). A standardized community level physiological profiling (CLPP) data analysis protocol was adapted and utilized for CW mesocosms. A new one-dimensional metric was developed to track community divergence using BIOLOGTM ECO plate data. The method proved easy to use, did not require a background in multivariate statistics, and accurately described community divergence in mesocosm systems. To study mesocosm biofilm-bound bacterial communities an appropriate detachment protocol was required. Various shaking protocols were evaluated for their effectiveness in the detachment of bacteria from mesocosm pea gravel, with a focus on detachment of viable and representative bacterial communities. A protocol based on mechanical shaking with buffer and enzymes was identified as an optimal approach and used further in this study. The bacterial communities associated with the interstitial water, pea gravel media, and rhizospheric regions from both planted and unplanted CW mesocosms were profiled using the CLPP method and compared. Vertical community stratification was observed for all mesocosm systems. Rhizospheric communities were found to be significantly more active than their gravel-associated counterparts, suggesting that although rhizospheric bacteria were less abundant in the mesocosms they may play a more significant role in the removal and fate of water born contaminants. The start-up dynamics of CW mesocosms was investigated using the CLPP and standard CW characterization methods over an eight month period. All mesocosms showed a steep increase in interstitial community divergence until day 75-100, at which point a steady-state was reached. The interstitial communities were also characterized in terms of similarity based on experimental design treatments (planted/unplanted and origin of seeding inoculum). Four stages were identified during the start-up consisting of an initial stage where mesocosm communities were differentiated based on origin of the inoculum, a period where adjustments and shifts occurred in all mesocosm, a time where all mesocosm communities were quite similar, and a final state where community differentiations were made based plant presence in the mesocosms.