College of Agriculture & Natural Resources

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    Development of a model framework for simultaneous synthesis and selection of Anaerobic Digester Structures
    (2021-07-12) ; Asiedu, Nana Yaw
    The anaerobic treatment process has increasingly been recognized as an efficient technology for sustainable nutrient recovery, renewable energy generation, and environmental sanitation due to its strong potential to mitigate current energy resource and climate change challenges. However, the success of industrial-scale anaerobic digestion is only possible if the following two prerequisite factors are met: availability of a sustainable supply of organic feedstock and design of optimal process configurations containing appropriate digester subunits that are well adapted to the characteristics of the feedstock of interest. A lot of combinations of the fundamental anaerobic digester types exist, which becomes impossible to test all the possibilities in order to determine the one with the absolute best performance. This study did not focus attention on devising new digesters with the aim of improving the performance of the system, but rather optimally arranged some combinations of plug flow reactors (PFRs) and continuous stirring tank reactor (CSTR) systems. The objective of study was to establish a framework based on multi-criteria decision analysis, for optimal selection of anaerobic digesters and practical implementation of digester networks, which is amendable to any substrate and digester configuration. Anaerobic treatability study was performed using pineapple waste, pig waste, abattoir waste and food waste to obtain cummulative biogas yield curves followed by development of the digester configurations using the attainable region technique. A hybrid Analytical Hierachy Process and Fuzzy Technique for Order Preference by Similarity to Ideal Solution was used in the selection of plug flow anaerobic digesters for the configurations. The following biogas volumes were obtained at the end of the 30 days retention period; for pig waste, for abattoir waste, for food waste and for pineapple waste. Quantity of feedstock used was 5kg per sample. A novel framework for the selection of multi stage anaerobic digesters has been presented. Optimal digester configurations obtained differ based on substrate used. The selected plug flow anaerobic digesters for subunit were Expanded Granular Sludge Bed for scenario 1, scenario 2 and scenario 3 were Anaerobic Baffled Reactor.
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    Prevalence and identification of yam viruses responsible for seed yam degeneration in the Ejurasekyedumase and Atebubu-Amantin Districts of Ghana
    (2021-06-28) Marfo, Esther Agyemang;
    Yam viruses are reported to be widespread in all areas where yam is grown. In Ghana, viral diseases are known to cause about 50% of yield reduction on yam. It was for this reason that this research was carried out to manage yam viruses in Ghana. Surveys were conducted in the 2015 and 2016 cropping seasons in two major growing districts, Ejura-Sekyedumase and AtebubuAmantin of Ghana to determine the prevalence of yam virus. There was the need to identify the specific viruses producing the symptoms that were observed during the survey, as such symptomatic leaf samples were taken for analysis at the laboratory using RT-PCR. Out of the 40 leaf samples collected from each district, Ejura-Sekyedumase District had six mixed infections for both Yam mosaic virus (YMV) and Yam mild mosaic virus (YMMV) while eight single infections were recorded for YMMV. Atebubu-Amantin District had 10 mixed infections for both viruses and eight single infections for YMV. Molecular-based diagnostics techniques were also employed to monitor the health status of seven plants (Diosecorea rotundata Poir) established from positive selection, of which five of them did not amplify for any of the two viruses tested while two amplified for both viruses that were tested. Seed yams (‘Dente’, ‘Pona’ and ‘Laribako’) selected in 2015 from symptomless or mildly infected plants (positive selection), as well as those purchased from the Ejura market (farmer practice) and those selected from field diseased plants were established in field experiments in 2016 and 2017 cropping seasons at Ejura and Fumesua using a 3 x 3 factorial in randomized complete block design. The performances of the three seed yam sources were compared for their reaction to yam mosaic virus infection and tuber yield. The three white yam (D. rotundata) varieties used were; ‘Dente’, ‘Pona’ and ‘Laribako’. Plants raised from positive selection performed significantly (P<0.05) better with least virus percentage infection and disease severity scores irrespective of the variety. Positiveiii selection Dente out-yielded farmer practice Dente and diseased Dente by 35 and 66.7% respectively in the 2016 cropping season at Ejura. Similar result was obtained at Fumesua with positive selection Dente out-yielding farmer practice and diseased seed yams by 32.6 and 60.7% respectively. In the 2017 cropping season, even though there was general yield reduction indicating loss of seed yam quality with time, similar trend occurred with positive selection plants performing significantly (P<0.05) better with least virus incidence and severity scores at both locations. Positive selection Laribako produced the highest yield at both locations. With farmers’ current practice of recycling seed yams from one season to another, this study showed that positive selection was a good approach to reducing virus load in farmers’ farms as well as reducing seed yam degeneration while maintaining fairly good yields.
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    Analysis of project management practices in the public sector-the case of Weija-Gbawe municipal assembly
    (2021-05-10) Pinkrah, Justice;
    The study was set out to assess the project management practices among MMDAs in Ghana using a case study of Weija-Gbawe Municipal Assembly in the Greater Accra Region of Ghana. The specific objectives were as follow; to identify the current project management practices carried out by the Weija-Gbawe Municipal Assembly and to identify the challenges associated with project management practices by the Weija-Gbawe Municipal Assembly. The study made use of descriptive survey designed to assess the project management practices and the challenges associated with it. A total number of 35respondents were selected from the assembly for the survey. The study used both primary and secondary data. The data was analysed using both qualitative and quantitative approaches. The study found that 80 percent of the respondents sees procurement activities at the Weija-Gbawe Municipal Assembly as a core activity whiles 20 percent sees it as a non-core activity. Also, majority of the respondents indicated that there was no specific unit designated by the assembly to carry out project management related activities and also there were no specific personnel assigned to carry out project management related activities. The study also revealed that the personnel/ units that undertake project management activities at the assembly were identified to be field technician, specific project manager to a project, procurement personnel, contractors, audit unit, M & E personnel and others such as contractors. With respect to the current project management practices by the Weija- Gbawe Municipal Assembly, the study revealed that the topmost project management practices carried out by the assembly were; setting up overall project mission, purpose and goals, effective team building, effective procurement plan, ensuring top management support, instituting a well-laid out project specifications, effective consultations with project stakeholders and setting up project scope. The study also found that the assembly does not effectively practice the following project management practices; project integration, deliberate quality management practices, effective communication among project team members, monitoring and evaluation activities with time management plan being the least practiced. The study found that the top seven most challenges constraints associated with project management practices by the Weija-Gbawe Municipal Assembly identified were; corruption, payment difficulties and delays, poor coordination and communication structures, political interference, delays by contractors, fiscal constraints and extensive controls and as well, poor understanding of procurement practices. The study therefore recommends that the Weija-Gbawe Municipal Assembly should set up a unit to be responsible for project management related activities. It is also recommended that the assembly put more attention and emphasis on the project management practices that they currently fail in terms of implementation. They are; project integration, deliberate quality management practices, effective communication among project team members, monitoring and evaluation activities with time management plan being the least practiced. The assembly should also work to ensure that corruption or its perception is minimized through transparent award of contracts and effective supervision of project delivery devoid from political influences and interference to ensure that projects are delivered in accordance with the right standards. It is finally recommended that personnel in the assembly in charge of project management should be given regular training on project management and its related activities to ensure that they are well equipped to implement projects of the assembly efficiently and effectiveness.
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    Impact of Arbuscular Mycorrhizal Fungi Inoculation on Soybean (Glycine max) Production in the Semi-Deciduous Forest Zone of Ghana
    (May, 2018) Thioub, Malamine
    Phosphorus (P) is an important but limiting major nutrient in crop production. Its availability in the soil and consequently for plant nutrition remains a major challenge. The overall aim of this study therefore was to assess the potential of four arbuscular mycorrhizal fungi (AMF) isolates in enhancing mineral P fertilizer use efficiency in soybean and their beneficial residual effects on succeeding maize crop. Two pot experiments were conducted under greenhouse conditions using sterile river sand and a non-sterile soil on which two soybean lines (TGx 1989-48 FN and TGx 1989-75 FN) were evaluated. The soybean lines were inoculated with the four mycorrhizal isolates (Glomus etunicatum, G. fasciculatum, G. mosseae and Rhizophagus irregularis) as a preliminary screening study to select the top 50% symbionts. A factorial arrangement using a completely randomized design was used. Furthermore, a two-year field experiment was also conducted following the screening study during the minor and major cropping seasons of 2016 and 2017 respectively to evaluate the potential of combined mycorrhizal inoculation and P mineral fertilizer in enhancing soil P availability, soybean growth and yield and economic profitability. The two aforementioned soybean lines used in the pot experiments were separately inoculated with the top 50% mycorrhizal isolates (G. mosseae and R. irregularis). An uninoculated control treatment was included. Triple superphosphate (TSP) was applied at three levels (0, 15 and 30 kg P ha-1). A split-split plot design with three replications was used; soybean lines as the main-plot factor, TSP rates as the sub-plot factor while the AMF isolates constituted the sub-sub plot factor. In a separate experiment, an early maturing maize variety (Omankwa) was planted following the minor cropping season of 2017 to evaluate the residual effects of the imposed treatments on root length colonization, N and P uptake, shoot biomass and grain yields. The greenhouse study revealed that R. irregularis and G. mosseae improved P uptake, plant height, stem girth and shoot biomass yield of soybean relative to G. etunicatum and G. fasciculatum. In the field experiment, inoculation with the selected AMF isolates combined with 15 kg P ha-1 resulted in the highest soybean root length colonization, P use efficiency, shoot and grain P uptake, plant height, shoot biomass and grain yields. Furthermore, AMF + 15 kg P ha-1 reduced soil microbial biomass P by stimulating P release by soil microbes and thus increased soil available P. Again, G. mosseae showed higher performance in soybean root length colonization and P uptake, which reflected in the better growth and yield improvement than R. irregularis. The economic analysis indicated that inoculation using the selected mycorrhizal isolates combined with 15 kg P ha-1 had the highest net benefit and marginal rates of return and is therefore economically more profitable for soybean production. Glomus mosseae, underfield conditions persisted even after two cropping years. Maize root length colonization was higher in plots previously inoculated with AMF, which reflected in highest maize shoot N and P uptake, grain P uptake, shoot biomass and grain yields relative to the control. This study established that, the appropriate management of AMF inoculation is a potential to reducing the use of inorganic P fertilizers.
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    Assessing the Effectiveness of Native Rhizobia as Potential Strains for Local Inoculant Production for Enhanced Cowpea and Groundnut Yields in Northern Ghana
    (October, 2018) Osei, Ophelia
    Efficient exploration of the legume-rhizobium symbiosis via inoculation with rhizobia is constrained by the limited knowledge on the fate of introduced strains under field conditions and the unavailability of effective native strains for use as local inoculants. This research therefore sought to address these challenges in four studies: i) nodule occupancy determination ii) identification of effective native isolates iii) symbiotic performance evaluation of elite native isolates under field conditions and iv) assessment of the persistence of elite isolates following field inoculation. Significant differences (p< 0.05) in shoot biomass of cowpea following inoculation was observed. The differences were explained via nodule occupancy studies by designing specific primers for the test strain Bradyrhizobium pachyrhizi BR 3262 (a recommended cowpea strain in Brazil) using the comparative genomics approach. Out of eleven specific primer pairs designed, the primers 2645 and 2736 were observed to be highly sensitive and reliably detected the target strains in nodules extracts of gnotobiotic system and potted soil grown cowpea. These two primers are thus novel tools for determining the fate of BR 3262 in field inoculation studies. The approach for designing specific primers in this study should be applicable to other bacteria/rhizobium strains whose genomic sequences are available. Bioprospecting for nodules of groundnut and cowpea cultivated in farmers’ fields without inoculation was done followed by isolation of rhizobium in the laboratory. Authentication and symbiotic effectiveness evaluation of the isolated rhizobium strains led to the selection of seven effective isolates. The nitrogen accumulated via BNF of the selected effective isolates was significantly higher (p< 0.05) compared to the –N control treatment. Treatment with isolate KNUST 1002 resulted in a total N accumulation that was comparable to the reference strain 32H1 on groundnut (BR 1 variety) grown in potted soils. Genetic characterization of the seven effective isolates revealed them as diverse with isolates KNUST 1003 and KNUST 1007 belonging to the Rhizobium tropici speices. The five remaining isolates were identified to belong to the Bradyrhizobium yuanmingense species. The two most effective isolates were evaluated in the field alongside a positive (with nitrogen) and negative (without nitrogen or inoculation) control on cowpea (Songotra variety) and groundnut (Chinese variety) in multi-locational trials in the Northern region of Ghana using the randomized complete block design. On the average, cowpea grain yields produced by the inoculated treatments were significantly (p< 0.05) larger than the –N treatment. Isolate KNUST 1002 produced the best average yield (1056 kg ha-1 ) which was significantly different from the other treatments. Groundnut yields on the other hand were significantly larger with isolate KNUST 1006 (1234 kg ha-1 ). The chemical properties of soils in the study locations generally showed low soil fertility. The different soil types significantly influenced the performance of treatments across the study locations. Twenty-six and 23% of the variability in grain yields of cowpea and groundnut respectively, was explained by the soil type and treatment interaction. These results imply that effective native isolates in this study can improve grain yields of cowpea and groundnut based on location specific recommendations. The persistence of effective isolates following previous inoculation on cowpea and groundnut was assessed in the 2017 cropping season on ten of the sites considered in 2016. Nodulation in both previously inoculated and re-inoculated plots were significantly higher than the un-inoculated plots (+N and –N). Nodule dry mass recorded for isolate KNUST 1006 in previously inoculated plots did not differ significantly from that of re-inoculated plots on both target host. However, the nodule dry mass recorded for isolate KNUST 1002 on cowpea in previously inoculated plots was significantly lower than in re-inoculated plots. Increases in grain yield of groundnut were significantly larger for treatment with isolate KNUST 1006 than the other treatments for previously inoculated and re-inoculated plots. Isolate KNUST 1002 on cowpea produced significantly higher yields than the other treatments in previously inoculated and re-inoculated plots. The type of legume host in each case influenced the performance of the isolates. There were no significant differences in the yields produced by either of the isolates in previously inoculated and re-inoculated plots. These results indicate that effective native isolates persisted and effectively nodulated the target legumes obviating the need for re-inoculation in subsequent cropping season. The outcomes of these studies have important implications for the use of effective isolates from this study as inoculants to improve cowpea and groundnut yields particularly in Northern Ghana.