School of Agricultural, Earth and Environmental Sciences

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A 40,000-year record of vegetation and fire history from the Tate Vondo region, Northeastern Southpansberg, South Africa.
(2014) Baboolal, Deeva Lata.; Finch, Jemma M.
Records from the Quaternary period are used to confirm possible inferred climatic changes, reveal the responses of species to these changes, and serve as an archive against which modern environmental dynamics can be assessed. Fueled by a need to understand current climatic changes, the call for palaeoclimatic research in the southern African subregion has become more compelling. In southern Africa, such research has been largely restricted to springs and swamps as the subregion lacks natural lakes, with some exception of a few coastal lakes such as Lake Sibaya and Lake Eteza. Due to the arid and semi-arid landscapes which prevail in southern Africa, there is a paucity of suitable sedimentary deposits in the region. The highly organic peat deposit of Mutale Wetland, situated in the Tate Vondo region of the northeastern Soutpansberg presents an ideal opportunity for conducting palaeoenvironmental research. The Mutale Wetland contains relatively old sediments dating back to >30,000 cal years BP, placing this record within the late Quaternary period. Palaeoenvironmental techniques including radiocarbon, pollen and charcoal analyses were applied to produce a palaeoenvironmental reconstruction for Tate Vondo. A 302 cm sedimentary core was extracted from the Mutale Wetland. Detailed analyses show that prior to ca. 34,000 cal yr BP, conditions were fairly warm and dry. This is inferred from a dominance of open grassland vegetation. An expansion of Podocarpus forests together with an increase in fynbos elements suggest a shift to cool, subhumid conditions during the LGM. Cooler conditions persisted until ca. 12,000 cal yr BP. Thereafter, a climatic amelioration was experienced. The appearance of low charcoal concentrations throughout the late Pleistocene suggests that fire was infrequent. Between ca. 4000 – 1500 cal yr BP, conditions became warmer and drier, inferred from the development of arid savanna vegetation. The sharp increase in charcoal after ca. 4000 cal yr BP, broadly coinciding with the arrival of the first agriculturalists in the area, has implications for the history of human occupation in the Soutpansberg rather than shifts in climate. The succession from savanna to fynbos vegetation together with expanded forests implies a return to cool and moist conditions from ca. 1500 – 400 cal yr BP. Arid savanna persists from ca. 400 to the present, implying warmer and drier conditions towards the present day. Furthermore, from ca. 400 cal yr BP, the pollen and charcoal record indicate that the majority of recent changes in vegetation have been driven by anthropogenic activity. This record has contributed to an improved understanding of late Quaternary changes in climate, vegetation history and human impact in the northeastern Soutpansberg.
A Bayesian geo-statistical approach for plantation forest productivity assessment after the fast-track land reform in Zimbabwe.
(2023) Chinembiri, Tsikai Solomon.; Mutanga, Onisimo.; Dube, Timothy.
The principal objective of the current study was to investigate how the new generation multispectral remote sensing, along with variants of the Bayesian hierarchical geostatistical methodology, could handle prediction uncertainty of carbon (C) stock. The assessment of C stock prediction uncertainty was conducted in a managed and disturbed plantation forest ecosystem located in Manicaland province of Zimbabwe. To achieve this, the study made use of ancillary data from the multispectral (Landsat-8 and Sentinel-2) remote sensing platforms, which informed the application of different inferential and methodological variants within the Bayesian hierarchical geostatistical framework. Allometric equations suited for the target plantation tree species in the sampled region were used to derive C stock from Above ground Biomass (AGB) sampled on 500 m2 circular supports. These Bayesian geostatistical models utilized a combination of Landsat-8 and Sentinel-2 derived vegetation indices, along with climatic and topographic variables. The study found that the Normalized Difference Vegetation Index (𝑁𝐷𝑉𝐼), Distance to settlements (𝐷𝐼𝑆𝑇), and Soil Adjusted Vegetation Index (𝑆𝐴𝑉𝐼) played crucial roles in influencing the spatial distribution of C stock in the studied region. Enhanced Vegetation Index (𝐸𝑉𝐼) is an insignificant predictor for both Landsat-8 and Sentinel-2 driven C stock predictions. Among the tested Bayesian approaches, the spatially varying coefficient (SVC) model, the multi-source data-driven Bayesian geostatistical approach, and the frequentist geostatistical framework were examined. Regardless of the various specifications for independent variables in the predictive C stock modelling within the Bayesian framework, 𝑁𝐷𝑉𝐼 and 𝐷𝐼𝑆𝑇 emerged as significant predictors of the modelled response variable. The non-stationary and Sentinel-2 driven Bayesian hierarchical model, with 𝑁𝐷𝑉𝐼 and DIST covariables, proved to be the most effective prediction model in the studied plantation forest ecosystem in Zimbabwe. This best-performing C stock predictive model was subsequently used to predict C stock under both current (1970-2000) and future (SSP5-8.5) 2075 climate scenarios. The results of the Bayesian constructed hierarchical model indicate a significant shrinkage of forest C stock density and distribution under the future SSP5-8 (2075) business-as-usual climate projection. Basically, the findings of this study highlight the critical role of new generation multispectral remote sensing and Bayesian geostatistical approaches in assessing and predicting carbon stock uncertainty in forest ecosystems. These insights have significant implications for informed land management strategies, aligning with the goals and recommendations of the Intergovernmental Panel on Climate Change (IPCC) to effectively address climate challenges and enhance sustainable land management practices.
A critical analysis of current approaches to SMME development and support within the eThekwini Municipal Area.
(2009) Chetty, Anneline.; Bob, Urmilla.
Small, Medium and Micro Enterprises (SMMEs) are considered to be the engines of growth of any economy. In the light of recent economic events and the recession that is surging rapidly across the globe, more and more attention is being focused on SMME development and support. Whilst there are a number of organisations (both public and private) which provide support to SMMEs within the eThekwini Municipality Area (EMA), the overall impacts of these initiatives on SMME growth and development is minimal and there is a dearth of studies that critically examine business support services for SMMEs which the public and private sectors provided. One of the major reasons for this minimal impact is the lack of communication and coordination between various service providers which often results in fragmentation and duplication of services. This study analyses the support measures offered to SMMEs not only from the perspective of the SMMEs themselves but also examines the perspectives of service providers from both the public and private sectors. This study is also placed within a multi-disciplinary conceptual framework which includes the political economy approach, neoliberalism, the public-private-sector debate and empowerment theories with specific reference to the South African context. This study is unique in that it analyses SMME development and support within the EMA from various perspectives within a single study. The objectives of this study were to investigate the awareness and experiences of SMMEs with regards to their support and development and also to critically examine the attitudes and perceptions of service providers (both public and private) towards SMME development and support. In addition, this study sought to assess the capacity of both the private and public sectors to provide effective support and development to SMMEs. An additional objective of this study was to determine the value placed on support measures by determining SMMEs’ willingness to pay for services provided, but more importantly to determine the attitudes of the public and private sectors towards the payment for services offered. Both qualitative and quantitative methods were adopted. In terms of the latter, quantitative surveys were conducted with 250 SMMEs who attended various fairs and conferences held across the EMA. Semi-structured interviews (qualitative approach) were conducted with representatives from the private and public sectors that provide support or services to the SMMEs in the EMA. In this regard, 53 representatives from the public sector and 50 from the private sector were interviewed. The analysis was undertaken thematically and, where relevant, findings pertaining to the different stakeholders interviewed were compared and discussed. Some of the key findings indicate that SMME respondents were more aware of local government and the services they provide than any other tier of government. Furthermore, SMME respondents within the study did not fully grasp the concept of Business Development Services (BDS) and the associated benefits for their business. SMMEs rely heavily on government to provide services free of charge. The main finding is that private sector service providers are better qualified, positioned and trained to provide BDS than the public sector whose main roles should be that of regulator, facilitator and promoter. Whilst government has been a strong proponent of SMME development and support since 1994, this study presents a strong case for the increased role of the private sector. In addition, this study also motivates that local government through their Municipalities can play a significant role in SMME development and support in partnership with the private sector.
A critical assessment of the Namibian protected area management effectiveness tracking tool.
(2010) Mulonga, Samison Nzehengwa.; Dent, Mark Clifford.
Protected Areas (PAs) are one of the most effective mechanisms for biodiversity conservation. They are found in almost every country and have been adopted by the international community through various conventions and agreements. However setting aside areas as protected areas does not automatically qualify them to be effectively managed. Research around the world has shown that some PAs are not well managed due to different reasons in different parts of the world. Therefore it is important to determine management effectiveness of PAs to ascertain whether they are managed according to the objectives for which they were created. The Management Effectiveness Tracking Tool (METT) is one of the tools developed to evaluate management effectiveness of PAs around the world. The tool has been implemented in a number of countries including Namibia where it has been modified into the Namibia Management Effectiveness Tracking Tool (NAMETT) through the United Nations Development Programme and Global Environment Facility’s Strengthening the Protected Areas Network (SPAN) project. However the effectiveness of this tool in providing necessary information about PA management effectiveness was not ascertained before implementation. The Namibian PA management authorities on the other hand need a tool for determining management effectiveness of PAs for management decision-making and as part of their obligations through international conventions which they signed. The aim of this research study was to analyse and assess the NAMETT as a management effectiveness tool for PAs in Namibia, by looking at the strength and weakness of the tool. This will inform whether its worthwhile adopting the tool as a standard management effectiveness evaluation tool for Namibia’s PAs. To accomplish this NAMETT assessment data obtained from the two NAMETT assessments undertaken by SPAN project was analysed. Furthermore different qualitative techniques were used including a semi-structured questionnaire as part of a case study approach. A comprehensive literature review was undertaken in the process and links to students undertaking similar research projects and professionals in the PA management industry were established and complemented the research data. Data obtained from NAMETT assessment undertaken by SPAN project appear to provide a picture of the different levels of management effectiveness in Namibia’s PAs suggesting the tool could be adopted for management effectiveness of Namibia’s PAs. Research data and information gathered shows that at the moment there is no management effectiveness tracking tool in Namibia. PA management authorities lack the necessary management effectiveness information for decision making. Currently only reports, the Incident Book Monitoring System (IBMS) and park inspections are the only sources of information for PA management authorities in Namibia. These tools are inadequate as they do not provide information at a strategic level which can help show trends and weakness and strength in PA management. Therefore a METT tool based on the World Commission on Protected Area’s Framework of which Namibia is a signatory is warranted. The NAMETT provides good information but lacks a link or section that should highlight the health of the ecosystem or provide information on biodiversity. Furthermore the tool has shortfalls in terms of implementation training and guidelines to assist implementers. Despite this, stakeholders who participated in the research project indicated that the tool should be adopted as the standard management effectiveness tool for PAs in Namibia. This however should come with alignment of the tool to local conditions and development of implementation guidelines as well as linkage to other form of PA management tools such as game counts and the IBMS. There is lack of robust management system for PAs in Namibia which will consolidate implementation of NAMETT. Such a system should involve planning, implementation, reporting and adaptive management. Therefore if NAMETT is to be adopted there is a need for such a system to be in place to enable data and information from the different tools to be able to complement each other for informed decision making about PA management.
A description of the chemical and physical growth of New Zealand white and chinchilla rabbits.
(2024) Eniwaiye, Adenike Adetutu.; Rani-Kamwendo, Zikhona Theodora.
This study investigates two key aspects in animal science: (i) describing the growth potential and chemical composition of two commercially bred rabbit strains, in order to optimize the composition of their feed based on variables predicted by simulation modelling; (ii) testing the hypothesis that the allometric relationship between body parts remains consistent across different strains, sexes, and body protein levels. In other words, the research assesses whether animal scientists have faced challenges in modifying the proportional relationship between the weight of different body parts of rabbits and their body protein weight. The primary goal of the study was to outline the physical and chemical transformations in the body composition of two commercially bred rabbit breeds, namely New Zealand White and Chinchilla, over a 126-day growth period. The key focus was on investigating how the growth performance of developing rabbits is affected by sex and age, considering the influence of body protein. Moreover, the research examined alterations in growth and variations in the physical and chemical elements of the body. To achieve the objectives, series of studies were conducted: In this experiment, a total of 220 rabbits, consisting of both New Zealand White and Chinchilla strains, were utilized. Weekly weighing of 100 rabbits from each strain were conducted, starting from day 14 (due to the fragility of the kittens at birth) and continuing until day 140, in order to assess the growth potential of each rabbit. Additionally, samples were collected from 120 rabbits from each strain at specific ages: day 14, 21, 28, 35, 42, 56, 70, 84, 112, and 140. Before slaughter, the animals underwent weighing to determine their weight exclusive of internal organs. Post-slaughter, their weight was measured again to discern the weightof internal organs, skin, and the weight without the skin. The dissected body parts were weighed, labeled, and stored in a freezer for subsequent thawing and mincing. The specimens were then subjected to freeze-drying to extract water content. Following this, they underwent further grinding before being analyzed for protein, lipid, and ash. Moreover, the Gompertz equation was applied to individual body parts and the protein weight of each body component. The parameters of the Gompertz equations were defined as the final weight of these components, their rate of maturation, and the time required to achieve the peak growth rate of each component. By utilizing data from each individual rabbit, allometric regressions were employed to establish the relationship between the weights of physical and chemical components. The natural logarithm of body protein weight served as the independent variable, while the natural logarithm of body component weight served as the dependent variable. A significant allometric relationship was found between body weight and pelt weight, as the weight growth process occurs continuously from birth to maturity. Body weights and chemical composition of males and females (bucks and does) of the two strains remained similar throughout the trial. Mature body weights for both strains (New Zealand White and Chinchilla) at 140 days averaged 1760 g and 1558 g; mature body protein weights averaged 95 g/kg and 61 g/kg; and mature body lipid contents averaged 40 g/kg and 55 g/kg, respectively. Rates of maturing per day of body weights for males and females of both strains averaged 0.0241 and 0.251; pelt-free, 0.0294 and 0.0251, and body lipid was 0.0441 and 0.0225, respectively. The rates for body protein differed between New Zealand White females and Chinchilla females (0.0172 vs 0.0256/d). Separate equations were needed for males and females to describe the allometric relationships between lipid and protein in the pelt-free body. The rate of maturing of pelt in the New Zealand White was higher in females than in males (0.0249 vs 0.0214/d), and the mature weight was lower in females than in males (45vs 52 g/kg), respectively. Common values of the sexes for both strains are represented when there were no apparent variations in the constant terms and regression coefficients. The saddle weights, regardless of the protein content in both sexes of the New Zealand White, can be described by a single constant term of 1.0193, and a lower single constant term value of -1.1070 in the Chinchilla rabbit. The goodness of fit (R2) for both strains was highest in the saddle with 0.974 and 0.957 in the New Zealand White and Chinchilla gigantas rabbits, respectively, while it was lowest (0.922) in the pelt of New Zealand White and hindlimb (0.892) of the Chinchilla gigantas rabbits. Sexes differed in the allometric relationships of all component parts measured in both breeds. A common relationship between the two strains could be used to predict the weights of all rabbit major component parts. Further studies are recommended to confirm the findings of this study. Keywords: Chemical, Chinchilla, Components, Physical, New Zealand white, Rabbits.
A framework to improve irrigation design and operating strategies in the South African sugarcane industry.
(2009) Jumman, Ashiel.; Senzanje, Aidan.; Lecler, Neil Louis.
The purpose of this study was to develop a framework to assess irrigation design and operating strategies. This objective was achieved successfully and the framework was applied to formulate guidelines to increase farm profitability whilst using scarce resources, such as water and electricity, effectively. The study was targeted at sugarcane irrigated with semi-permanent irrigation systems. “ZIMsched 2.0”, a water balance and crop yield prediction model and the “Irriecon V2” economic assessment model were available at the start of the study. The missing link, however, was a relatively cost effective and efficient method to design and cost irrigation hardware alternatives. Irrigation hardware impacts on both the agronomic and economic performance of systems, for example, through different peak design capacities and associated operating limitations. Thus, a novel, spreadsheet-based irrigation design tool, with an automated costing component, was developed to complete the framework. The framework was used to investigate the costs and benefits of potential design and operating solutions to a selection of irrigation issues, including: over-irrigation on shallow soils, the opportunity to shift electricity use out of expensive peak periods and, the opportunity to demonstrate the benefits of deficit irrigation strategies. For shallow soils, the increase in system hardware costs, needed to better match water application to soils, increased margins due to more effective water use. Innovative deficit designs and operating strategies allowed for reductions in water and electricity costs. The reduced costs, however, did not always offset yield penalties and revenue loss resulting from water stress. The financial benefits of deficit irrigation strategies were shown when water savings were used to convert dry land cane into irrigated cane. This highlighted the differences between the direct and opportunity costs of water. Finally, a field work component, relating to the precise monitoring of irrigation strategies and corresponding crop responses was included in this study. Systems which enabled soil water potential and stalk extension to be monitored remotely via the internet were considered useful for the successful implementation of an optimum irrigation strategy. The easily accessible data allows for effective decision making and more importantly, reassures famers of the current state of their crop.
A laboratory and glasshouse investigation on the effect of liming with fly ash and processed stainless steel slag on two contrasting South African soils.
(2008) Ndoro, Esina Tambudzayi.; Hughes, Jeffrey Colin.
Soil acidity is a major land degradation problem that limits crop production globally. The high cost of traditional liming materials (calcitic limestone, dolomite etc.) and the vast areas of land that require liming have led to the exploratory utilisation of alkaline industrial by- products such as fly ash and stainless steel slag. The liming potential and effects of liming with fly ash (from the Duvha power station) and processed stainless steel slag (Calmasil) on two acid soils were investigated in this study. The quality of fly ash and Calmasil as liming materials and their potential impacts on the soil quality and plant growth were investigated. The effects of liming with these materials on soil pH, EC, extractable Al, Mn, base cations and trace elements were investigated in an incubation experiment. A glasshouse trial was conducted to assess the effects of these materials on the growth of an acid intolerant crop, perennial rye grass. The incubation and glasshouse study were of a factorial design with two acid soils (the Avalon and Inanda soils), three materials (fly ash, Calmasil and lime); and five application rates of 0, 50, 100, 200 and 400% of the recommended optimum liming rate (OLR) for the growth of perennial rye grass. Characterization of fly ash showed that the major elements (>5%) present (Si > Al > Fe) are not comparable to lime (Ca > Si > Mg) and that it has a low liming potential (calcium carbonate equivalence (CCE) of 9.6%) in comparison to lime. The chemical composition of Calmasil is comparable to lime with Ca > Si > Mg as the major elements and it has a very high liming potential (CCE = 97%). The incubation experiment showed that adding fly ash and Calmasil increased the pH of both soils. However, at the optimum liming rate (100% OLR), only the treatment with Calmasil in the Avalon soil attained pH levels within the desired pH range. Extractable Al and Mn decreased with addition of fly ash and Calmasil to levels comparable to lime in the incubated soils. Addition of fly ash and Calmasil also increased the extractable base cations of both soils. The yield-response of perennial rye grass to treatments in both soils was in the following order: fly ash > Calmasil > lime. Application of fly ash at > 200% OLR in the Avalon soil caused injury of ryegrass. Application of fly ash and Calmasil at lower rates has great agronomic potential in ameliorating soil acidity.
A review of the fluvial geomorphology monitoring of the receiving streams of the Mooi-Mgeni [River] Transfer Scheme Phase 1.
(2009) Hunter, Alistair Malcolm Scott.; Kotze, Donovan Charles.; Dent, Mark Clifford.; Archer, Lynette Deborah.
The Mgeni River is the major water resource for the eThekwini Metropolitan and Msunduzi Municipalities. At the end of 2002, the Mooi-Mgeni Transfer Scheme Phase 1, which transfers water from the Mooi River into the Mgeni catchment to augment the water supply to this region, was completed. The interbasin transfer of water resulted in the loss of habitat, erosion of the stream channel and transformation of the riparian zone in the receiving streams. Stream regulation resulting in an altered flow regime is considered the greatest threat to a riverine environment. An Environmental Management Plan (EMP), incorporating fluvial geomorphological monitoring procedures, was implemented to monitor the impact of the transfer on the receiving streams, the Mpofana and Lions Rivers, and to determine the rate and magnitude of erosion. A comparison of the geomorphological monitoring procedure of the EMP with best practice geomorphological monitoring derived from a review of the national and international stream geomorphological literature was conducted in this study. In addition, the implementation of the EMP geomorphological monitoring procedures was described and onsite observations of physical impacts on the receiving streams were completed. The geomorphological monitoring of the EMP included the use of erosion pins, survey of stream cross-sections and fixed-point photography. Photographs and data were collected from February 2003 to June 2006. The comparison of these monitoring methods against stream assessment best practices revealed the strengths and weaknesses of the geomorphological monitoring implemented in the receiving streams. Several key weaknesses were revealed. Firstly, an inadequate number of stream cross sections was included in the monitoring procedures. Secondly, although the erosion pins indicated some general trends in the erosion of the stream channel, they did not give a true impression of the rate and magnitude of change in slope and channel width of the stream, and the location of the erosion pins sites did not take into account the actual direction of flow during transfer as erosion pin sites were selected during low flow conditions. In addition, it was difficult to determine whether the erosion pins had been lost due to erosion or to turbulence. The results were difficult to assess and did not show whether the erosion was localised at the pins or the section of bank or stream profile. Thirdly, analysis of platform changes in the stream channel (e.g. through a comparison of aerial photograph sets) was lacking and no attempt was made to integrate the results from the different methods. Overall, the study concluded that the geomorphological monitoring of the EMP was limited, and it did not highlight the rate and magnitude of erosion in the receiving streams. Based on the findings of this study, recommendations are provided for geomorphological monitoring of the receiving streams of the Mooi Mgeni Transfer Scheme.
A simulation study of cane transport system improvements in the Sezela Mill area.
(2009) Giles, R. C.; Bezuidenhout, Carel Nicolaas.
The South African sugar industry is of significant local and international importance and covers an area in excess of 450 000 hectares. This area yields approximately 21 million tons of sugarcane per annum which is transported almost exclusively by road, from farms to the sugar mills. The industry is under increasing economic pressures to improve its productivity and competitiveness and sugarcane transport in the sugarcane supply chain has been identified as one area where large improvements and associated cost reductions can be made. This is mainly due to the excess in number of vehicles in the inbound transport system, the high relative cost of transport compared to other production costs in producing sugarcane, and the high fixed costs associated with truck fleet operations. A simulation case study of the transport system was completed in 2005 in the Sezela Mill area in which approximately 2.2 million tons of sugarcane is transported per annum over an average distance of 29 km by approximately 120 independently managed vehicles owned by a wide range of hauliers and individual growers. This amounts to an estimated cost of R58 million per annum. This study investigated the potential savings that could occur as a result of a central fleet control system with integrated vehicle scheduling. A scheduling software package named ASICAM, which resulted in significant savings in the timber industry (Weintraub et al, 1996), was applied within the Sezela region. Results suggested that the number of trucks in the fleet could theoretically be reduced by at least 50%, providing that a central office controls vehicle movements and that all hauliers serve all growers in an equitable fashion. In addition, investigations towards decreasing loading times, decreasing offloading times, changing vehicle speeds and increasing payloads by reducing trailer tare mass showed further reductions in the number of trucks required.
A study of bruchid resistance and its inheritance in Malawian dry bean germplasm.
(2007) Kananji, Geoffrey Acrey Duncan.; Melis, Robertus Johannes Maria.; Derera, John.; Laing, Mark Delmege.
Dry bean (Phaseolus vulgaris L.) is economically and nutritionally an important legume, not only in Malawi, but in many parts of Africa and Latin America. Unfortunately, two bruchid species (Acanthoscelides obtectus Say, and Zabrotes subfasciatus Boheman) are known to cause extensive damage in storage, reducing the economic importance, food value and planting value of the crop. The aim of this study was to: i) ascertain farmers’ perceptions of the importance of bruchids as storage pests, and to identify their preferred varietal traits in dry beans; ii) screen Malawian dry bean landraces for effective and adaptable sources of resistance to the two bruchid species; iii) determine the gene action and inheritance of bruchid resistance. Farmers’ perceptions on the importance of the two bruchid species to beans both in the field and in storage were established using a participatory rural appraisal (PRA) in three extension planning areas (EPAs) in Lilongwe agricultural development division (ADD). Results confirmed that the two bruchid species are important storage pests, causing serious storage losses among smallholder farmers. In the absence of any control measures, farmers indicated that more than 50% of their stored beans could be lost to bruchids. Indigenous bruchid control measures are not very effective, making it necessary to search for other control methods. It was also clear from the PRA results that breeders need to consider both agronomic and culinary traits in bean cultivar development. This would enhance uptake of newly developed varieties. To address the problem of bruchid damage experienced by smallholder farmers, a total of 135 dry bean genotypes, comprising 77 landraces and 58 improved varieties (obtained from collaborating partners) were tested under laboratory infestation (nochoice test methods) and field infestation (free-choice test methods). The objective of this study was to identify effective sources of resistance to the two bruchid species. Results of the study showed that there was a wide variation among the genotypes for resistance to the two bruchid species. Overall results showed that 88% of the genotypes ranged from susceptible to highly susceptible to Z. subfasciatus and only 12% of the genotypes were moderately resistant to resistant. Genotype screening for resistance to A. obtectus showed that only 12.5% were resistant, whereas 87.5% were moderately to highly susceptible. All of the improved genotypes were 100% susceptible to A. obtectus in storage. One landrace, KK35, consistently showed a high level of resistance to both bruchids under laboratory infestation, with results similar to the resistant checks (SMARC 2 and SMARC 4), while another landrace, KK90, displayed stable resistance under both laboratory and field infestation. However, performance of most genotypes was not consistent with field and laboratory screenings, suggesting that mechanisms of bruchid resistance in the field are different from that in the laboratory and field screening should always be used to validate laboratory screening. Resistance in the field was not influenced by morphological traits. The seed coat played a significant role in conferring resistance to both bruchid species in the laboratory, whereas arcelin did not play any significant role in conferring resistance in the landraces. The inheritance of resistance to A. obtectus was studied in a 6 x 6 complete diallel mating design, involving crosses of selected Malawian dry bean landraces. The F1 crosses, their reciprocals, and six parents were infested with seven F1 generation (1 to 3 d old) insects of A. obtectus in a laboratory, no-choice test. There were significant differences among genotypes for general combining ability (GCA) and specific combining ability (SCA). However, SCA accounted for 81% of the sum of squares for the crosses, indicating predominance of the non-additive gene action contributing to bruchid resistance. A chi-square test for a single gene model showed that 5 of the 13 F2 populations fitted the 1:2:1 segregation ratio of resistant, intermediate and susceptible classes, respectively indicating partial dominance. The eight F2 populations did not conform to the two gene model of 1:4:6:4:1 segregation ratio of resistant, moderately resistant, moderately susceptible, susceptible and highly susceptible classes, respectively. Average degree of dominance was in the partial dominance range in five F3 populations, but in general resistance was controlled by over-dominance gene action in the F2 populations. The additive-dominance model was adequate to explain the variation among genotypes indicating that epistatic effects were not important in controlling the bruchid resistance. The frequency distribution of the 13 F3 populations for resistance to A. obtectus provided evidence for transgressive segregation, suggesting that resistance is conditioned by more than one gene. Reciprocal differences were not significant in the F2 generation seed; but were significant in four crosses in the F3 generation seed for adult bruchid emergence, suggesting that maternal effects or cytoplasmic gene effects also played a role in the inheritance of resistance to the common bean weevil. Through this study, important sources of bruchid resistance in dry bean have been identified in Malawian landraces (KK35, KK90 and KK73). These resistant sources will be used in a breeding programme to develop bruchid resistant bean cultivars, as well as improve resistance in susceptible commercial bean cultivars currently grown by farmers in Malawi.
A systems-thinking based evaluation of predator conflict management on selected South African farms.
(2008) Snow, Timothy V.
The backbone of this study was a systems thinking based analysis of the management and control of predators as practiced in South Africa since the advent of Europeans in 1652. The first bounties were introduced for a variety of animal species in 1656. Many species became labeled as vermin and were persecuted, often with the intention of eradication. A variety of controls have been applied, of which many have not kept pace with contemporary thinking or technology, and which by simply killing predators fail to address the crux of the issue of predator – livestock conflict. Many of the methods used cannot be applied to specifically remove an individual damage-causing animal. Considerable collateral ecological damage is inflicted by the killing of animals regarded as innocent bystanders. The objective of the analysis was to highlight the futility of temporary solutions which fail to resolve the conflict in the long term. These quick fixes frequently perpetuate an ecological imbalance which exacerbates the predator – livestock conflict. The analysis used raw data from a questionnaire survey conducted by the Poison Working Group of the Endangered Wildlife Trust (EWT-PWG) (2003). The EWT-PWG intended to assess pesticide abuse as toxicant for predators by farmers, and to identify all control methods used. The data forthcoming was Cartesian in nature and a fixed snap-shot in time. This study sought to identify the root cause of the conflict by applying systems thinking which added the dimension of cause and effect interrogation. The study categorised and described predator conflict management methods as lethal or preventative, and assessed each category in archetypal terms from a systems thinking perspective. It also sought to identify leverage points, or small changes which have profound effects, to stimulate a change in approach to humanpredator conflict management. In order to assess and illustrate the positive change brought about by application of preventative methods, a small group of farmers who had initiated changes in their predator conflict management over the five years subsequent to the EWTPWG survey were selected from the original group for reassessment. Through evaluation of predator conflict management methods from a systems thinking perspective, and by probing learning processes, the shortcomings or failure of inappropriate management responses to conflict situations were shown to exacerbate conflicts. Contrarily, it was illustrated that application of systems thinking and a process of addressing the root cause of conflict issues in predator conflict management, was a longer term solution. The study illustrated that application of long term proactive prevention and conflict avoidance principles, can offer long term solutions for predator conflict managers.
Abandoning the Ark in Durban: development, displacement, resettlement and livelihood struggles.
(2021) Fitzgerald, Tara Jade.; Maharaj, Bridgemohan.
Forced removals, the theme of this thesis, through evictions, clean-up campaigns and development-induced displacement, results in the ‘hygienisation’ of public space and the ‘violent un-homing’ of vulnerable communities. The Ark Christian Ministries Church (ACMC) was established in 1982 in Durban’s notorious Point Precinct, offering shelter and rehabilitation opportunities for socially excluded and marginalised persons in the inner city. As the city forged ahead with the Point Waterfront Development mega-project and prepared to host the 2010 FIFA World Cup, the Ark was shut-down in 2004. Notwithstanding a spirited resistance, one hundred families were forced to relocate to Welbedacht East, 30km from the Point Precinct. The aim of this study is to examine the implications of Development-Induced-Displacement and Resettlement (DIDR) on the livelihoods of those displaced from the Ark homeless shelter in the Point Precinct in Durban, and their survival strategies after relocating to the urban edge in Welbedacht. Influenced by theories of displacement, social justice and human rights, this thesis analysed the displacement, resistance, relocation and livelihood struggles of the Ark dwellers. A mixed-method approach was adopted in this study, drawing from qualitative and quantitative techniques and information from documents. The study found that those displaced remained socially excluded and marginalised in Welbedacht and expressed a deep sense of detachment and hopelessness. Their lives were characterised by unemployment, poverty and social pathologies. The former Ark residents failed to restore their livelihood opportunities and remain in a constant state of precarity. The study identified a new form of displacement. ‘New-Place Displacement’ refers to the inability to adapt to the new environment or integrate with surrounding communities. Instead, the ‘Arkians’ remained in a constant state of alienation in Welbedacht.
The above-ground biomass composition and nutrient content of commercial Eucalypts and their use in managing sustainable intensive forestry in South Africa.
(2003) Herbert, Martin Antony.; Zwolinski, Janusz.
A study was undertaken of the biomass composition of ten eucalypt species growing on five sites in the timber growing regions of southeastern Mpumalanga. The species comprised E. deanei, E. dunnii, E. elata, E. fastigata. E. grandis, E. macarthurii, E. nitens, E. saligna, E. smithii and E. viminalis. The average tree height was 19.3 m and dbh 15.9, with stocking at 1494 stems/ha and merchantable yield at 153 t/ha. The sites had been established under commercial conditions seven years earlier as a series of identical site-species trials, and differed widely with respect to air temperature and effective precipitation. The soils were derived from granite, and either shallow and rocky (Glenrosa form) or deep and friable (Inanda forms). Sample trees were felled at the height of summer, separated into the biomass components of leaves, branches, on-tree dead matter, bole bark and bole wood, and weighed for fresh mass. Sub-samples were taken of each component for laboratory determinations of moisture and nutrient content, as well as bole wood density. Statistical analysis of the results show significant differences between species and sites as well as site species interactions for the tree mass of biomass components, and nutrient composition and water content. While overall E. smithii and E. dunnii produces the largest biomass, there are strong site interactions due to the varying degrees of site specificity required by different species. The proportions of the different biomass components differ between species and across sites, with the bole mass fraction increasing as growth rate improves. Biomass moisture is highest in bark and leaves, especially for the Viminales species group of the genus Symphyomyrtus. This group also has the highest wood density, while density within the stem is remarkably uniform for most species. Density generally increases with tree vigour. Nutrient concentrations are greatest in leaf and bark and least in bole wood, and are strongly influenced by soil nutrient status. There are considerable differences between species, with the subgenus Monocalyptus showing generally the lowest values. Models are developed to estimate biomass components from tree mensurational parameters and their nutrient content from soil variables. Nutrient budgets are developed on an equivalent tree mass basis to estimate the quantity of nutrients required to grow biomass. Nutrient quotients of the biomass produced per unit of nutrient are calculated to compare the efficacy with which biomass is produced per species, and comparisons made for average growing conditions across the study region. While the most economical subgenus is Monocalyptus, the most efficient of current commercial species is E. smithii, followed by E. nitens, E. macarthurii, E. grandis and E. dunnii. Nutrient export during harvesting exceeds natural inputs, is exacerbated by 60% on average when retaining bark on logs, and more than doubled if slash is burnt. Further research is required into estimating soil reserves and extending the study to other site types.
Abscisic acid metabolism in a Citrus Sinensis flavedo enzyme system.
(1998) Kalala, Maloji.; Cowan, Ashton Keith.
This research project had its major objective the unequivocal demonstration that the plant growth regulator, abscisic acid could be produced in vitro from labelled precursors. In addition, this project was intended to demonstrate the metabolic relationship between β, β-xanthophyll turnover and ABA biosynthesis. Finally attempts were made to isolate the enzyme responsible for the cleavage of the immediate xanthophyll precursor to ABA, 9'-cis-neoxanthin. This was achieved using a cell-free system developed from Citrus flavedo which demonstrated formation of xanthoxal and abscisic acid from zeaxanthin, antheraxanthin, violaxanthin and neoxanthin. In addition product abscisic acid was shown to incorporate label from mevalonic acid lactone establishing the terpenoid origin of this plant growth regulator. 9'-cis-neoxanthin cleavage enzyme was present in the Citrus cell-free system, partially purified, and separated from lipoxygenase activity and shown to convert 9'-cis-neoxanthin into xanthoxal and related but unidentified neutral products.
The acceptance of indigenous leafy vegetables and their contribution to household food security in Limpopo and Mpumalanga provinces, South Africa.
(2022) Zulu, Sinethemba.; Ngidi, Mjabuliseni Simon Cloapas.
The dietary shift from indigenous leafy vegetables to cash crops production and consumption increased the risk of micronutrients deficiency diseases, especially among rural-poor communities. The less consumption of ILVs promotes hunger and food insecurity among rural and urban households. An increase in consumption of these leafy vegetables helps minimize malnutrition, hunger, and food insecurity. Each ILV contain different levels of micronutrients, suggesting that diversifying ILVs in consumption has the potential to reduce health conditions associated with micronutrient deficiency. Therefore, understanding consumer acceptance of indigenous leafy vegetables (ILVs) is important in enhancing their consumption levels to increase micronutrient intake. However, the determinants of consumers' acceptance of ILVs, vis-à-vis its potential impact on household food security, is neglected by researchers, as a result, declining. This study was set out to assess the determinants of acceptance of indigenous leafy vegetables by consumers in Limpopo and Mpumalanga provinces. The study used secondary data that was collected by the South African Vulnerability Assessment Committee in 2016. A total of 1520 respondents were selected from the two provinces using a multistage stratified sampling method. In analyzing the determinants of consumers' acceptance of ILVs, a seemingly unrelated regression (SUR) model was employed. The results of SUR showed that the gender of the household head, marital status, HIV status, wages/salary, and grants were statistically significant in influencing the acceptance of ILVs by consumers. The study further revealed that amaranth and cleome were the most accepted leafy vegetables while blackjack was the least accepted one. Education and marital status had a negative influence on the acceptance of all leafy vegetables being investigated in this study. While estimating the impact of ILVs consumption on household food security, the household food insecurity access scale (HFIAS) was used to determine the household food security status of the respondents. In the same vein, the endogenous switching probit model (ESPM) was employed to estimate the impact of ILVs consumption on household food security status. The results from the household food insecurity access scale (HFIAS) showed that a large proportion of the population was food secure while a small portion of the population was food insecure. The correlation coefficients rho_1 and rho_ 0 in the ESRM were negative (-0.992) and positive (0.970), respectively. This indicates that self-selection occurred in the consumption of ILVs between both consumers and non-consumers of ILVs. The results from descriptive statistics revealed that most consumers did not produce ILVs but consumed them. While a small number of farmers produced ILVs yet did not consume them. The household size and wealth index variables were positive and significant to the consumption of ILVs. On the other hand, age, gender, and education variables had a negative influence on the consumption of ILVs. To increase the acceptance of ILVs, especially the least accepted ones. The study recommends that extension officers must educate farmers about the importance of these leafy vegetables. NGOs can provide agricultural input such as seedlings, fertilizers, farm machinery to encourage the production of underutilized ILVs among smallholder farmers, including blackjack. Strategies to enhance value addition and sensitization of consumers to traditional knowledge regarding leafy ILVs, and their nutritional importance to the human diet are required.
Access to irrigation and its impact on vulnerability to poverty and food security amongst South African farming households.
(2023) Adetoro, Adetoso Adebiyi.; Ngidi, Mjabuliseni Simon Cloapas.; Danso-Abbeam, Gideon.
The significance of participating in irrigation technology in eliminating vulnerability to poverty and improving farming households’ food security status cannot be overemphasized. Numerous studies have empirically examined the influence of farm management practices, including irrigation, on poverty reduction and overall household well-being. However, a notable gap exists in the literature concerning the specific impact of irrigation farming on vulnerability to poverty, multidimensional household poverty, and the welfare of rural farming households. This study aims to address this gap by exploring the nuanced relationship between irrigation participation and key welfare indicators within the context of rural communities. The study consists of four main objectives, each of which is an article and chapter of this thesis. In each of the articles, the significance, methods, data, findings and policy implications are detailed, and these are presented in the below sections. In the first objective, the study employed the documentary analysis approach and bibliometric technique to mine and analyse relevant documents for evaluating facts and evidence, which largely concurs with the method of information gathering used in the qualitative study method. In the analysis period (1991-2022), the most published articles on impacts of irrigation on household poverty appeared to be in 2022, indicating the growing concern on depleting food resource access. Overall, the findings revealed that irrigation adoption produced better yields and increased farm incomes thereby reducing rural household poverty as well as vulnerability to poverty. The study, therefore, suggests that more sophisticated and innovative methods, such as the proposed multi-level framework, conglomerate approach, and community-led solutions, should be developed and implemented to promote household food dynamics, food system resilience, and governance in the context of South Africa. The second segment of the research focuses on the effect of participation in irrigation farming on food security among rural farming households. The study employed an endogenous treatment effect with ordered outcome to achieve its objectives. The empirical findings indicate that the engagement of rural households in irrigation farming has a higher probability of mitigating food insecurity. This is attributed to the enhanced productivity and improved food accessibility that irrigation farming provides, particularly in the face of severe weather-induced shocks like drought. The findings also showed that the gender of the household head, the size of the household, unemployment status, access to market outlets, remittances and crop diversification (CDV) factors increase the likelihood of rural farmers’ involvement in irrigation farming, as well as reduces their food insecurity. Based on the findings, the study suggested that government intervention policies and a restructuring of rural operations to include more technological innovations such as advanced irrigation systems be reviewed. The third segment of the study focuses on the vulnerability of smallholder farmers to multidimensional poverty, which was carried out using the Alkire Foster multidimensional poverty index developed by the Oxford Poverty and Human Development Initiative. The findings showed that the deprivation indicator ranges from 5% to 90%, where about 66% and 55% were deprived of food security (SDG2) and education (SDG4), respectively. The results of the probit analysis reveal that gender, remittances, crop diversification (CDV), education, seasonal farming and market outlets significantly influence the multidimensional poverty and vulnerability to multidimensional poverty of rural households in the study areas. The last part of the study examines the factors that influence farmers’ participation in irrigation farming, as well as how it affects farmers’ welfare (proxy by food consumption expenditure per capita) and household poverty (indicated by the poverty gap index, poverty severity and poverty vulnerability). The endogenous switching regression (ESR) model was employed to account for selection bias that could be caused by both observed and unobserved household factors, including observed and unobserved farm-level factors. The empirical results show that gender, household size, educational attainment, crop diversification and market outlets, among others, influenced farmers’ decisions to practise irrigation farming. Farmers engaging in irrigation farming have their food consumption per capita increased by 44%, while nonparticipants would have increased their consumption expenditure per capita by 23% if they had participated. Moreover, the participating farmers reduced their poverty gap index by 20% and poverty severity by 22%, whereas non-participating farmers could have reduced their poverty gap index and poverty severity by 5% and 17%, respectively had they engaged in irrigation farming. Participation in irrigation farming also reduced poverty vulnerability by 25%, while non-participants may have reduced poverty vulnerability by 3% had they participated. Overall, the study suggests that the household food dynamics and food system resilience and governance in the context of South Africa need to devote more time to reliable and innovative methods, such as the conglomerate approach, community-led solutions and appropriate strategies, which need to be implemented in order to mitigate the collapse of the nation’s food systems. In addition, the study recommend that enhancing farmers’ access to irrigation is crucial for meeting the Sustainable Development Goals (SDGs), which aim to eradicate poverty in all its manifestations everywhere. Lastly, the study suggests that improving policies related to improving education and increasing crop diversification among other factors, could contribute to reducing the multidimensional poverty and the households’ vulnerability to poverty.
The accuracy of arm-associated height estimation methods compared to true height in a multi-racial group of young South African adults.
(2015) Lahner, Christen Renée.; Kassier, Susanna Maria.; Veldman, Frederick Johannes.
Background: Stretch stature is the gold standard for measuring true height, but when this is not possible height estimation methods are used. To date, only two South African studies regarding height estimation techniques have been published. Objective: To investigate the accuracy of arm-associated height estimation methods used for the calculation of true height compared to stretch stature in young South African adults. Design: A cross-sectional descriptive design was employed. Setting: Pietermaritzburg, Westville and Durban, KwaZulu-Natal, South Africa, 2015. Subjects: Convenience sample (N=900) aged 18 to 24 years, which included an equal number of subjects from both genders (n=150 per gender) stratified across race (White, Black and Indian). Results: Highly significant differences exist between genders (p<0.001), where males had larger stretch statures and arm-associated measurements than females (p<0.001). Highly significant differences exist between race groups (p<0.001), where whites had significantly different stretch statures as well as different armassociated measurements compared to Blacks and Indians. Some similarities were found between race groups, especially between Blacks and Indians. Arm-associated height estimation methods can be used as estimates of true height in accordance with the following study findings: (i) among Black African males, the World Health Organisation (WHO)-adjusted equation would seem to be the most appropriate, followed by demi-span male equation; (ii) among Black African females, the demispan female equation would seem to be the most appropriate, followed by total armspan; (iii) among Caucasian males, the total armspan would seem to be the most appropriate, followed by half-armspanx2; (iv) among Caucasian females, the total armspan would seem to be the most appropriate, followed by half-armspanx2; (v) among Indian males, the demi-span male equation would seem to be the most appropriate, followed by the WHO-adjusted equation; and (vi) among Indian females, the WHO-adjusted equation would seem to be the most appropriate, followed by demi-span female equation. Discussion:. The anthropometric variation between genders and race groups was linked to the exposure to secular growth conditions, which influences a subject's physiological ability to achieve their maximal height. The Vitruvius theory was proposed where total armspan potentially represents a subject's maximal height, and the ability for them to reach that height is dependent on exposure to consistent ambient secular growth conditions during the window period and beyond. Conclusion: In conclusion, this study's findings provides a baseline for future height studies to be conducted on the South African population, where each anthropometric method should be validated for each race and gender.
Achieving local economic development through natural resource-based tourism in KwaZulu-Natal.
(2003) Trotter, Dayle Carey.; Hill, Trevor Raymond.
A number of development strategies and programmes are currently being explored in South Africa as a part of a renewed ihitiative to overcome the imbalances persisting from the apartheid era with respect to development, wealth, income and opportunity, and in order to address problems increasing unemployment brought on by the decline of traditional employment sectors. Local Economic Development (LED) is one such strategy that seeks to utilize local resources and skills in order to promote economic growth and create employment opportunities. Similarly, tourism, which has become one of the most critical forces shaping the world's economy, has been recognised as a potential growth alternative in South Africa, and is being increasingly implemented into LED strategies across the country. Although the studies that have identified the link between tourism and LED are increasing, it is clear that research on the topic remains limited. This research therefore contributes to the existing literature, and investigates how three localities in Kwazulu-Natal have identified the tourism potential of the locally available natural resources, and how different actors have embarked on tourism-based projects that have sought to achieve LED. A series of semi-structured interviews formed the principle research method and information was obtained over a period of a year from a number of key stakeholders and role-players in each case study. It was found that all three case studies have created employment opportunities and have empowered local communities through skills development and training. This research attempts to highlight the potential opportunities and limitations of the pursuit of natural resource-based tourism as a catalyst for local economic development, such that other localities that are seeking to adopt a similar approach may learn from these experiences.
Adaptation and behaviour of finishing pigs to Vachellia tortilis leaf meal inclusion.
(2017) Thabethe, Fortune.; Chimonyo, Michael.
The broad objective of the study was to determine the adaptation and behaviour of pigs fed on incremental levels of Vachellia tortilis leaf meal based diets. Forty-eight clinically healthy male pigs Large White × Landrace with a mean (± SD) body weight of 63.8 ± 3.28 kg were randomly assigned to individual pens in a completely randomized design. Eight pigs were fed on diets that contained 0, 30, 60, 90, 120 and 150 g/kg DM of V. tortilis leaf meal. Pigs were fed ad libitum and had free access to clean water throughout the experiment. Average daily feed intake (ADFI), average daily gain (ADG) and gain: feed ratio (G: F) were determined weekly. The adaptation period was calculated at the end of the experiment for each individual pig. Coefficient of variation (CV) of feed intake across V. tortilis leaf meal diets was calculated. Number of visits to the feeder were calculated. The time spent eating, drinking, standing, lying down, sniffing, biting objects and licking objects were observed using six closed circuit television cameras (CCTV) once a week for three days. There was a quadratic decrease (P < 0.001) in ADFI, while ADG increased linearly (P < 0.001) with incremental level of V. tortilis leaf meal. Incremental level of V. tortilis leaf meal increased G: F ratio quadratically (P < 0.001). A linear increase in adaptation period of pigs was observed (P < 0.05) with increasing inclusion level of V. tortilis leaf meal. The variation of feed intake, expressed as a coefficient of variation, increased linearly (P < 0.05) with increasing inclusion level of V. tortilis leaf meal. Increasing inclusion levels of V. tortilis leaf meal linearly iii decreased time spent eating, lying down and the number of visit to the feeder (P < 0.05). Time spent standing and biting objects increased linearly with increasing inclusion level of V. tortilis leaf meal (P < 0.05). There was no relationship (P > 0.05) between V. tortilis leaf meal inclusion and time spent drinking, sniffing and licking of objects. It can be concluded that pigs require a long time to adapt to Vachellia diets. Increasing levels of V. tortilis leaf meal also alters time spent on behavioural patterns of pigs.
An adaptation of the SCS-ACRU hydrograph generating technique for application in Eritrea.
(2004) Ghile, Yonas Beyene.; Schulze, Roland Edgar.; Smithers, Jeffrey Colin.
Many techniques have been developed over the years in first world countries for the estimation of flood hydrographs from small catchments for application in design, management and operations of water related issues. However, relatively little attention has been directed towards the transfer and adaptation of such techniques to developing countries in which major hydrological decisions are crucially needed, but in which a scarcity of quality hydrological data often occurs. As a result, hydrologists and engineers in developing countries are frequently unable to alleviate the problems that extreme rainfall events can create through destructive flood flows or, alternatively, they do not possess the appropriate tools with which to design economically viable hydraulic structures. Eritrea is a typical example of a developing country which faces difficulties in regard to the adaptation of an appropriate design flood estimation technique for application on small catchments. As a result, the need has arisen to adapt a relatively simple and robust design flood model that can aid hydrologists and engineers in making economic and safe designs of hydraulic structures in small catchments. One objective of this study was, therefore, to review approaches to hydrological modelling and design flood estimation techniques on small catchments, in order to identify the barriers regarding their adaptation, as well as to assist in the selection of an appropriate technique for application, in Eritrea. The southern African adaptation of the SCS (i.e. Soil Conservation Service) design hydrograph technique, which has become a standard method for design flood estimation from small catchments in that region, was selected for application on small catchments in Eritrea for several reasons. It relies on the determination of a simple catchment response index in the form of an initial Curve Number (CN), which reflects both the abstraction characteristics and the non-linear stormflow responses of the catchment from a discrete rainfall event. Many studies on the use of SCS-based hydrological models have identified that adjustment of the initial CN to a catchment's antecedent soil moisture (ASM) to be crucial, as the ASM has been found to be one of the most sensitive parameters for accurate estimates of design flood volumes and peak discharges. In hydrologically heterogeneous regions like Eritrea, the hypothesis was postulated that simulations using a suitable soil water budgeting procedure for CN adjustment would lead to improved estimates of design flood volumes and peak discharges when compared with adjustments using the conventional SCS antecedent moisture conditions (SCS-AMC) method. The primary objective of this dissertation was to develop a surrogate methodology for the soil water budgeting procedure of CN adjustment, because any direct applications of soil water budgeting techniques are impractical in most parts of Eritrea owing to a scarcity of adequate and quality controlled hydrological information. It was furthermore hypothesised that within reasonably similar climatic regions, median changes in soil moisture storage from the socalled "initial" catchment soil moisture conditions, i.e. LIS, were likely to be similar, while between different climatic regions median LISs were likely to be different. Additionally, it was postulated that climatic regions may be represented by a standard climate classification system. Based on the above hypotheses, the Koppen climate classification, which can be derived from mean monthly rainfall and temperature information, was first applied to the 712 relatively homogeneous hydrological response zones which had previously been identified in southern Africa. A high degree of homogeneity of median values of LIS, derived by the daily time step ACRU soil moisture budgeting model, was observed for zones occurring within each individual Koppen climate class (KCC) - this after a homogeneity test had been performed to check if zones falling in a specific KCC had similar values of median LIS. Further assessment within each KCC found in southern Africa then showed that a strong relationship existed between LIS and Mean Annual Precipitation (MAP). This relationship was, however, different between KCCs. By developing regression equations, good simulations of median LIS from MAP were observed in each KCC, illustrating the potential application of the Koppen climate classification system as an indicator of regional median LIS, when only very basic monthly climatological information is available. The next critical task undertaken was to test whether the estimate of median LIS from MAP by regression equation for a specific Koppen climate class identified in southern Africa would remain similar for an identical Koppen climatic region in Eritrea. As already mentioned, LIS may be determined from daily time step hydrological soil moisture budget models such as ACRU model. The performance of the ACRU stormflow modelling approach was, therefore, first verified on an Eritrean gauged research catchment, viz. the Afdeyu, in order to have confidence in the use of values of LIS generated by it. A SCS-ACRU stormflow modelling approach was then tested on the same catchment by using the new approach of CN adjustment, termed the ACRU-Koppen method, and results were compared against stormflow volumes obtained using the SCS-AMC classes and the Hawkins' soil water budgeting procedures for CN adjustment, as well as when CNs remain unadjusted. Despite the relatively limited level of information on climate, soils and land use for the Afdeyu research catchment, the ACRU model simulated both daily and monthly flows well. By comparing the outputs generated from the SCS model when using the different methods of CN adjustment, the ACRU-Koppen method displayed better levels of performances than either of the other two SCS-based methods. A further statistical comparison was made among the ACRU, the SCS adjusted by ACRU-Koppen, the SCS adjusted by AMC classes and the unadjusted SCS models for the five highest stormflows produced from the five highest daily rainfall amounts of each year on the Afdeyu catchment. The ACRU model produced highly acceptable statistics from stormflow simulations on the Afdeyu catchment when compared to the SCS-based estimates. In comparing results from the ACRU-Koppen method to those from the SCS-AMC and unadjusted CN methods it was found that, statistically, the ACRU-Koppen performed much better than either of the other two SCS based methods. On the strength of these results the following conclusions were drawn: • Changes in soil moisture storage from so-called "initial" catchment soil moisture conditions, i.e. L1S, are similar in similar climatic regions; and • Using the ACRU-Koppen method ofCN adjustment, the SCS-SA model can, therefore, be adapted for application in Eritrea, for which Koppen climates can be produced from monthly rainfall and temperature maps. Finally, future research needs for improvements in the SCS-ACRU-Koppen (SAK) approach in light of data availability and the estimation ofL1S were identified. From the findings of this research and South African experiences, a first version of a "SCSEritrea" user manual based on the SAK modelling approach has been produced to facilitate its use throughout Eritrea. This user manual, although not an integral part of this dissertation, is presented in its entirety as an Appendix. A first Version of the SCS-Eritrea software is also included.

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