Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Automated teller machines (ATMs) are a very important part of our daily lives. They are the key to accessing our bank accounts. Where they are located can determine how easy or difficult it is to access our bank accounts. ATMs are primarily designed to serve customers and should therefore be accessible and convenient to the customers. Hence, the question of where the ATMs should be located is a prime issue to both the customer and the bank. A geographical information system (GIS) is a tool that can be used to assist in answering questions about locations. It provides a means of determining optimal locations for any spatially referenced object. Against this backdrop, this study was undertaken to develop a method with which GIS can be used to find optimal locations for ATMs, taking Stellenbosch as a case study. Firstly, it was necessary to understand current factors affecting ATM locations, both locally and internationally. An extensive literature survey was conducted to gain an understanding of problems relating to locating ATMs. Interviews with bank officials were conducted to help understand more fully the problems and the current procedures used in locating ATMs. Obtaining the public's perception of ATMs was also paramount to this study. A household questionnaire survey was conducted in Stellenbosch to ascertain how customers feel about the current location of ATMs in Stellenbosch. Secondly, GIS was considered and evaluated as a tool to find optimal locations for ATMs. This involved discussing the capabilities of GIS and the various options that banks may have available. Thirdly, the ability of using GIS to find optimal sites was tested by applying GIS to Stellenbosch. Having done this, GIS was then used to find additional ATM sites. The results provide a basis for banks to locate ATMs in general. Keywords: GIS, ATMs, location, optimal locations, location-allocation, models, MINDISTANCE, MAKCOVER, MAXATTEND, MINDISTPOWER. / AFRIKAANSE OPSOMMING: Outomatiese tellermasjiene (OTMs) speel 'n baie belangrike rol in ons lewens vandag aangesien ons die meeste van ons banktransaksies deur middel van 'n OTM doen en ons bankrekeninge sodoende kontroleer. Die OTMs se primere doel is om 'n diens aan bank kliente te lewer, dus is dit uiters belangrik om liggings te identifiseer wat gerieflik en toeganklik is vir die kliënte en die bank. 'n Geografiese inligtingstelsel (GIS) kan gebruik word om vrae in verband met bestaande en beplande liggings vir OTMs te beantwoord. Die stelsel kan optimale liggings identifiseer vir spesefieke doeleindes, byvoorbeeld OTMs, ens. Teen hierdie agtergrond is hierdie studie onderneem om 'n metode te ontwikkel waarmee GIS aangewend kan word om optimale liggings vir OTMs te vind, met Stelle bosch as 'n gevallestudie. Ten eerste was dit nodig om die huidige faktore met betrekking tot die liggingskeuse vir OTMs, beide in die buiteind en die binneland, te ondersoek. "n Uitgebreide literatuursoektog is geloods om die probleme wat gepaard gaan met die bepaling van die keuse van "n OTM ligging, te bestudeer. Onderhoude is gevoer met amptenare van verskillende banke om die probleme rondom die kies van OTM-plasings te verstaan. Kliënte is ook genader vir hulle idees, benogdighede en probleme oor OTM-liggings in Stellenbosch. Tweedens is GIS geëvalueer as 'n moontlike stelselom die beste liggings vir OTM'e te bepaal. Dit het 'n bespreking van die vermoëns en voordele van GIS behels, sowel as 'n oorsig van beskikbare opsies vir die bank. Die vermoë om met die gebruik van GIS addisionele liggings vir OTMs in Stellenbosch te identifiseer, is daarna getoets. Die resultaat bied aan banke "n keuse van alternatiewe liggings vir die plasing van OTMs. Sluitelwoorde: GIS, ATMs, ligging, optimale ligging, ligging-toesegging, modelle, MINDISTANCE, MAXCOVER, MAXA1TEND, MINDISTPOWER

Thesis (MA (Geography and Environmental Studies)--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Issues relating to self-employment and the development of the so-called New Economy gained not only new founded momentum, but also more all round interest over the last two decades, especially from academic researchers. During this time, new emphasis was placed on the importance and significance of location. Consequently, urban areas were finally regarded as instrumental within providing the central backdrop for the competing nature of the global economy. Due to this fact, the emphasis again shifted from competition to the stimulation of investment. Local Economic Development (LED) was the South African method of doing so. Entrepreneurship became a major driving force of the South African market. Within the same past two decades substantial growth took place within Home-based Work, especially within Home-based Enterprise (HBE) activities. This can be attributed to the flexible organization of production that a home-based work (HBW) lifestyle can provide. Within the South-African context there does exists some empirical observations relating to HBW and TBE activities, but these studies have mostly focused on informal neighborhoods and other less affluent areas. This study however places the emphasis on the existence of HBW, selfemployment and HBE’s within all the income-group neighbourhoods in George. The existence of the traditional Spazashops and Shebeens is included, because these examples are extremely relevant within the South African context, but other specialized careers such as medical practitioners, childcare professionals, consultants, and producers of various products are also examined. The study wants to contribute to the discussion of urban sustainable development through the inclusion of HBW and HBE’s as potential strategies to reach sustainability within communities. Because of this, the primary aims and objectives of this study include the nature and extent of HBE activities throughout various neighbourhoods located on the periphery of the urban centre in George. A deeper understanding regarding the reasons behind the locational decision process (thus why participating home- businesses chose George as the location for their Small, Medium or Micro Enterprises (SMME’s) and the consequential location movement of these businesses was also examined. The spatial and structural relationships that exist between the growth and/or movement of formal businesses in the study area was further observed by the creation of a database stretching from 1995 to 2005 that lists and map these locational changes. / AFRIKAANSE OPSOMMING: Kwessies wat verband hou met selfwerksaamheid en die ontwikkeling van die sogenaamde Nuwe Ekonomie het oor die afgelope twee dekades reeds heelwat aandag vanaf navorsers geniet. Hernieude klem is geplaas op die belangrikheid van ligging, en stede word deesdae beleef as instrumenteel om ’n sentrale en mededingende rol te speel binne die globale ekonomie. As gevolg van hierdie stedelike mededingendheid het die fokus verskuif na die bevordering van investering. Gevolglik het Plaaslike Ekonomiese Ontwikkeling (PEO) in Suid-Afrika toenemende verandering na markgedrewe entrepreneurskap veroorsaak. Daar het ook tydens die afgelope twee dekades ’n aansienlike groei in Tuisgebaseerde Werk (TGW), veral onder Tuisgebaseerde Besigheid (TGB) aktiwiteite plaasgevind. Hierdie fenomeen kan toegeskryf word aan faktore soos die buigbare organisasie van produksie wat met ʼn TGW lewenswyse kan voorsien. Daar bestaan wel ’n aantal empiriese waarnemings rakende TGW en TGB aktiwiteite in Suid-Afrika maar hierdie studies is meestal gemik op informelenedersettings en mindergegoede areas. Hierdie studie plaas dus groter klem op die bestaan van TGW, selfwerksaamheid en TGB’e binne al die inkomste woonbuurte in George. Die bestaan van TGB’e in die minder-gegoede areas vorm ook deel van hierdie studie (byvoorbeeld die tradisionele Spaza of Huiswinkel en Smokkelhuis/ "Shebeen“ aangesien dit onmisbaar is binne die Suid-Afrikaanse konteks, maar ander gespesialiseerde beroepe wat ook in ’n woonbuurt kan voorkom (byvoorbeeld mediese praktisyns, kinderbewaarskole, konsultante en vervaardigers van allerlei) word ook ondersoek. Hierdie studie will graag bydra tot die bespreking van stedelike volhoubare ontwikkeling deur TGB’e te oorweeg as potensiële strategie om hierdie volhoubaarheid te bereik in gemeenskappe. Daarom is die primêre doelstellings van hierdie studie om die aard en omvang van TGB aktiwiteite tussen verskillende woonbuurte op die stedelikehinderland (in die omtrek van die stedelike kern) in George te ondersoek, ’n diepere begrip te bereik rakende die redes vir die besluite van hierdie deelnemende tuisondernemings (Klein-, Medium- en Mikro-ondernemings) om spesifiek George as vestiging te kies en laastens, die ruimtelike en strukturele verhoudinge wat duidelik is vanuit die formele groei (formele besighede se uitbreiding en/of verskuiwing) in George sedert 1995.

Thesis (MSc (Geography and Environmental Studies))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The automation of information extraction from earth observation imagery has become a field of active research. This is mainly due to the high volumes of remotely sensed data that remain unused and the possible benefits that the extracted information can provide to a wide range of interest groups. In this work an earth observation image processing system is presented and profiled that attempts to streamline the information extraction process, without degradation of the quality of the extracted information, for geographic object anomaly detection. The proposed system, implemented as a software application, combines recent research in automating image segment generation and automatically finding statistical classifier parameters and attribute subsets using evolutionary inspired search algorithms. Exploratory research was conducted on the use of an edge metric as a fitness function to an evolutionary search heuristic to automate the generation of image segments for a region merging segmentation algorithm having six control parameters. The edge metric for such an application is compared with an area based metric. The use of attribute subset selection in conjunction with a free parameter tuner for a one class support vector machine (SVM) classifier, operating on high dimensional object based data, was also investigated. For common earth observation anomaly detection problems using typical segment attributes, such a combined free parameter tuning and attribute subset selection system provided superior statistically significant results compared to a free parameter tuning only process. In some extreme cases, due to the stochastic nature of the search algorithm employed, the free parameter only strategy provided slightly better results. The developed system was used in a case study to map a single class of interest on a 22.5 x 22.5km subset of a SPOT 5 image and is compared with a multiclass classification strategy. The developed system generated slightly better classification accuracies than the multiclass classifier and only required samples from the class of interest. / AFIKAANSE OPSOMMING: Die outomatisering van die verkryging van inligting vanaf aardwaarnemingsbeelde het in sy eie reg 'n navorsingsveld geword as gevolg van die groot volumes data wat nie benut word nie, asook na aanleiding van die moontlike bydrae wat inligting wat verkry word van hierdie beelde aan verskeie belangegroepe kan bied. In hierdie tesis word 'n aardwaarneming beeldverwerkingsstelsel bekend gestel en geëvalueer. Hierdie stelsel beoog om die verkryging van inligting van aardwaarnemingsbeelde te vergemaklik deur verbruikersinteraksie te minimaliseer, sonder om die kwaliteit van die resultate te beïnvloed. Die stelsel is ontwerp vir geografiese voorwerp anomalie opsporing en is as 'n sagteware program geïmplementeer. Die program kombineer onlangse navorsing in die gebruik van evolusionêre soek-algoritmes om outomaties goeie beeldsegmente te verkry en parameters te vind, sowel as om kenmerke vir 'n statistiese klassifikasie van beeld segmente te selekteer. Verkennende navorsing is gedoen op die benutting van 'n rand metriek as 'n passings funksie in 'n evolusionêre soek heuristiek om outomaties goeie parameters te vind vir 'n streeks kombinering beeld segmentasie algoritme met ses beheer parameters. Hierdie rand metriek word vergelyk met 'n area metriek vir so 'n toepassing. Die nut van atribuut substel seleksie in samewerking met 'n vrye parameter steller vir 'n een klas steun vektor masjien (SVM) klassifiseerder is ondersoek op hoë dimensionele objek georiënteerde data. Vir algemene aardwaarneming anomalie opsporings probleme met 'n tipiese segment kenmerk versameling, het so 'n stelsel beduidend beter resultate as 'n eksklusiewe vrye parameter stel stelsel gelewer in sommige uiterste gevalle. As gevolg van die stogastiese aard van die soek algoritme het die eksklusiewe vrye parameter stel strategie effens beter resultate gelewer. Die stelsel is getoets in 'n gevallestudie waar 'n enkele klas op 'n 22.5 x 22.5km substel van 'n SPOT 5 beeld geïdentifiseer word. Die voorgestelde stelsel, wat slegs monsters van die gekose klas gebruik het, het beter klassifikasie akkuraathede genereer as die multi klas klassifiseerder.

Thesis (MSc (Geography and Environmental Studies))--Stellenbosch University, 2008. / Accelerating urban growth places increasing pressure not only on the efficiency of infrastructure and service provision, but also on the natural environment. City managers are delegated the task of identifying problem areas that arise from this phenomenon and planning the strategies with which to alleviate them. It is with this in mind that the research investigates the implementation of an urban growth model, SLEUTH, as a support tool in the planning and decision making process. These investigations are carried out on historical urban data for the region falling under the control of the Cape Metropolitan Authority. The primary aim of the research was to simulate future urban expansion of Cape Town based on past growth patterns by making use of cellular automata methodology in the SLEUTH modeling platform. The following objectives were explored, namely to: a) determine the impact of urbanization on the study area, b) identify strategies for managing urban growth from literature, c) apply cellular automata as a modeling tool and decision-making aid, d) formulate an urban growth policy based on strategies from literature, and e) justify SLEUTH as the desired modeling framework from literature. An extensive data base for the study area was acquired from the product of a joint initiative between the private and public sector, called “Urban Monitoring”. The data base included: a) five historical urban extent images (1977, 1988, 1993, 1996 and 1998); b) an official urban buffer zone or ‘urban edge’, c) a Metropolitan Open Space System (MOSS) database, d) two road networks, and d) a Digital Elevation Model (DEM). Each dataset was converted to raster format in ArcEdit and finally .gif images were created of each data layer for compliance with SLEUTH requirements. SLEUTH processed this historic data to calibrate the growth variables for best fit of observed historic growth. An urban growth forecast was run based on the calibration parameters. Findings suggest SLEUTH can be applied successfully and produce realistic projection of urban expansion. A comparison between modelled and real urban area revealed 76% model accuracy. The research then attempts to mimic urban growth policy in the modeling environment, with mixed results.

Thesis (MSc) -- Stellenbosch University, 2012. / ENGLISH ABSTRACT: One of the main objectives of the South African Wine of Origin Scheme (SAWOS) is to guarantee the quality of wine products emerging from South Africa’s viticultural production areas by preventing the abuse of names of products originating from outstanding viticultural areas. The study of terroirs contributes to knowledge that assists in delimiting potential viticultural areas in South Africa. Terroirs are areas with homogeneous groups of natural factors that, with the aid of effective management, have the potential to produce a unique product over a recognizable period. Natural terroir units (NTU) reflect the integration of relatively homogenous environmental factors, which include topography, climate, soil and geology. This study investigates the use of geographic information systems (GIS) and remote sensing methods in the identification of NTU in the Robertson wine district. Existing topographical, soil, geological and climatic GIS data layers were collected at various scales. In addition to this spatial data, orthorectified and radiometrically corrected SPOT 5 and ASTER satellite imagery were used to classify the land use/cover using an object-based image analysis (OBIA) approach. Eight land use/cover classes were distinguished by a sequential ruleset and an overall accuracy of 81.2% was achieved. The land use/cover layer was combined with the slope aspect and soil landscape to provide a three-component NTU description. One hundred and seventy NTU were identified, of which fifty five units exist for agriculture. These NTU can be used for site selection of agricultural produce and effective planning and management of land use. Climate was not included in the delimitation of NTU because the coarse resolution of climatic data could not be used to distinguish between different NTU. Therefore, all NTU identified in this research has similar climatic conditions. The major drawback of GIS-assisted terroir studies is the difficulty of representing a number of NTU on one GIS map. Therefore, it is recommended to associate the NTU map with a table of the classes instead. Furthermore, the accuracy, scale and resolution of available GIS data in South Africa influence the delimitation of NTU. Although remote sensing was found to provide efficient methods for land cover mapping, the use of multiseasonal satellite images would classify vineyards more efficiently because such an approach accounts for the different growth cycles of grapevines. / AFRIKAANSE OPSOMMING: Een van die hoof doelwitte van die Suid-Afrikaanse Wyn van Oorsprongskema (SAWOS) is om die kwaliteit van wynbouprodukte afkomstig van Suid-Afrikaanse wingerdbougebiede te verseker. Die studie van terroirs is geïdentifiseer as ‘n metode om moontlike wingerdbougebiede in Suid-Afrika af te baken. Terroirs is gebiede met relatief homogene natuurlike faktore wat oor ‘n erkenbare tydperk en met behulp van effektiewe bestuur die vermoë het om ‘n unieke produk te lewer. Dié natuurlike faktore word, “natuurlike terroir eenhede” (NTE) genoem en sluit topografie, klimaat, grond en geologie in. Hierdie navorsing ondersoek die gebruik van geografiese inligtingstelsels (GIS) en afstandswaarnemingstegnieke om NTE in die Robertson-wyndistrik te identifiseer. Bestaande ruimtelike topografiese-, grond-, geologiese- en klimaatdata is op ‘n verskeidenheid skale versamel. Bykomend tot hierdie ruimtelike data, is ortogekorrigeerde en radiometries-gekalibreerde SPOT 5 en ASTER satellietbeelde gebruik om landgebruik/ -bedekking te klassifiseer. Objekgerigte beeldanalise (OGBA) is toegepas tydens hierdie klassifikasie en agt landgebruik/ -bedekkingsklasse is onderskei deur gebruik te maak van ‘n stapsgewyse reëlstel. OGBA het ‘n algehele akkuraatheid van 81.2% gelewer. Die landgebruik/ -bedekkingsdata is gekombineer met hellingaspek en die grondlandskap om ‘n drieledige NTE-beskrywing te lewer. Een honderd en sewentig NTE is geïdentifiseer waarvan daar vyf-en-vyftig eenhede vir landbou bestaan. Hierdie NTE kan aangewend word vir die selektering van geskikte terreine vir landbou-gewasse en effektiewe grondgebruikbeplanning en -bestuur. As gevolg van die bestaande klimaatdata se growwe resolusie, was dit ongeskik om te onderskei tussen verskillende NTE. Dus heers daar soortgelyke klimaatstoestande vir elke NTE wat in hierdie navorsing geïdentifiseer is. Die grootste stremmende faktor wat GIS-verwante terroir navorsing beïnvloed, is die uitdaging om ‘n groot getal NTE op een kaart voor te stel. Daarom is dit beter om die NTE kaart met ‘n tabel te assosieer. Verder beïnvloed die akkuraatheid, skaal en resolusie van beskikbare digitale geografiese data in Suid-Afrika die afbakening van NTE. Alhoewel bevind is dat afstandwaarneming ‘n effektiewe metode is om landbedekking te karteer, sal die gebruik van meerseisoenale satellietbeelde wingerde meer doelmatig karteer omdat dit verskeie siklusse in die groei van wingerde in ag neem. SLEUTELWOORDE EN FRASES terroir, natuurlike terroir eenhede (NTE), geografiese inligtingstelsels, afstandwaarneming, wingerdkunde

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Despite recorded mountain wave related aircraft accidents in South Africa, very little literature exists on South African mountain waves. This study discusses the results of a mountain wave study in the Hex River Mountains in the Western Cape province of South Africa. The aim of this study was to measure mountain wave turbulence on the lee side of the mountains by conducting weather balloon soundings on the upwind and lee sides of the mountains. These soundings were performed over four days in the winter and spring, with each field day representing different synoptic scale weather conditions. Lee wave rotors were detected from several of the lee wave soundings. Significant values of horizontal vorticity around a north-south axis (y-component horizontal vorticity) were detected. The instrumentation was highly sensitive and able to measure even weak up and downdraft velocities associated with the rotors. Strong downdrafts were measured some mountain waves, but no strong downdrafts were detected near rotors which occurred below the mountain waves. The two dimensional positions of balloons were only available after a considerable amount of reanalysis. If this data can be made available onsite shortly after soundings, it can be used to decide where to move launch sites to, in order to obtain optimal results. / AFRIKAANSE OPSOMMING: Ten spyte van gedokumenteerde berggolf-verwante vliegongelukke, bestaan baie min literatuur oor Suid Afrikaanse berggolwe. Hierdie tesis bespreek die resultate van ‘n berggolfstudie in die Hexrivier Berge in the Weskaap Provinsie van Suid- Afrika. Die doel van hierdie studie was om die berggolfturbulensie aan die lykant van die berge te meet deur middel van weerballonopstygings aan beide die winden lykante van die berge. Hierdie opstygings is oor ‘n tydperk van vier winter en lente dae uitgevoer, met elkeen van die dae wat verskillende sinoptiese weersomstandighede verteenwoordig het. Rotors is waargeneem in die data van verskeie ballonopstygings wat aan die lykant uitgevoer is. Beduidende waardes van horisontale vortisiteit rondom ‘n noord-suid as (y-komponent horisontale vortisiteit) is gemeet. Die instrumentasie was hoogs sensitief en kon selfs swak op- en afstrominge meet. Sterk afstrominge is waargeneem in berggolwe, maar nie in die omgewing van rotors wat onmder die berggolwe voorgekom het nie. Die twee-dimensionele posisies van ballonne was slegs na aansienlike heranaliese van die data beskikbaar. Indien hierdie data kort na opstygings beskikbaar is tydens veldwerk, kan dit help met besluite oor alternatiewe posisies waarvandaan ballonopstygings gedoen kan word ten einde optimale resultate te bekom.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: South Africa is rich in biodiversity among which are semi-domesticated vegetable species which are known as wild or indigenous vegetables. These wild indigenous vegetables have been reported to be good in nutritional qualities such as macro and micronutrients. However, there is still a high prevalence of malnutrition; especially micronutrient deficiencies among low or marginal income bracket of the population. The use of indigenous vegetables has been proposed as part of the solutions to the problems of micronutrient malnutrition among these populations. Indigenous vegetables are an important source of food in the maize based subsistence farming sector of rural South Africa. Their main role is as relish as they are used as an accompaniment for staple cereal based diets. They are also generally reported to be rich in micronutrients. Although they may be consumed in small quantities, they influence the intake of cereal staples, manage hunger and play a central role in household food security for the poorer rural groups. Mixing several indigenous vegetables species in one meal contributes to dietary diversity in terms of more vegetable types as well as in terms of choice of relish. For some very poor families indigenous vegetables are substitutes for some food crops. The seasonal occurrence of these vegetables leaves many families without a food source during the off-season. Indigenous vegetables increase agro-biodiversity at the household level. This agro-biodiversity helps in buffering against the accumulation and multiplication of pests and diseases and provides important cover for the soil. Further research on agronomic, social and economic dimensions is required to understand the roles of IV in subsistence farming systems in South Africa. The survey study revealed that indigenous vegetables were important in the diets of most rural people in the study area. They were consumed as relish although they were not being cultivated. Their method of acquisition was gathering from homesteads and the wild. These vegetables were also believed to be medicinal. The local naming of wild vegetables varied among villages in the same district such that a vegetable in one village was assigned to a different species of vegetable in another village. They were reportedly abundant during summer and there was a decrease in availability off-season leaving vulnerable people who rely on them with a food shortage. The utilisation of wild vegetables among South Africans is reported to be declining due to over reliance on introduced temperate species. Efforts to domesticate and cultivate wild vegetables could be hampered by several factors including seed dormancy and premature flowering. In this present study dormancy was observed in C. olitorius. The response of wild genotypes of C. olitorius with different seed sizes to various dry heat and hot water treatments was evaluated. Steeping seeds in boiling water (95oC) for ten seconds and soaking seeds in a hot water bath at 80oC for ten minutes resulted in the highest response to germination in this species. The study also recorded significant interactions between heat treatment and seed sizes. We concluded that C. olitorius seeds of different sizes require diverse durations of exposure to heat treatment methods to break dormancy caused by an impermeable seed coat. Cleome gynandra is another species that is consumed as a vegetable in various parts of the world including Africa. The plant is also used as a medicinal herb for the treatment of various human diseases. Among the wild vegetables, C. gynandra has been reported to flower prematurely, a phenomenon known as bolting and common in many vegetable crops. Premature flowering (bolting) can be as a response to temperature extremes and photoperiod and affects many other leafy vegetables such as lettuce (Lactuca sativa), spinach (Spinacea oleracea) and mustard rape (Brassica juncea). Bolting leads to production losses in leaf vegetable crops as they flower before they have produced an economic yield. The removal of flowers and nitrogen application resulted in significant increases in the fresh and dry weight of cleome leaves. Removal of flowers resulted in a 46% increase in fresh weight of leaves. The observed positive response of leaf yield to removal of flowers offers a possible way to deal with the problem of bolting. The continuous removal of the flowers leads to increased utilisable leaf yield. The application of incremental amounts of nitrogen top dressing results in increased leaf yield in C. gynandra. The response of selected indigenous vegetables (Corchorus olitorius and Amaranthus cruentus) to micronutrients added to the soil was compared with the response of a reference crop; Swiss chard (Beta vulgaris var. cicla). For all the levels of micronutrients applied, Swiss chard accumulated Cu, Zn and Mn in the leaves at significantly (p<0.01) higher concentrations than the wild vegetables. Variations between the vegetables in the micronutrients were greater for Zn (72–363 ppm) and Mn (97.9–285.9 ppm) for Cu (8.8–14 ppm). C. olitorius had the least capacity to concentrate Mn and Zn in the leaf, which suggested that this vegetable is a less attractive candidate for agronomic bio-fortification of these elements. However, C. olitorius accumulated Fe at a significantly higher concentration (327 ppm) in the leaves than did Amaranthus (222 ppm) or Swiss chard (295 ppm). Sulphur as a macronutrient varied little in the plant species tested. The mean S concentration in the leaves ranged from 0.26% in C. olitorius to 0.34% in Amaranthus cruentus and Swiss chard. We concluded that the different vegetables have different abilities to take up Cu and Zn in the order Swiss chard > Amaranthus > Corchorus, and that they responded to micronutrients added to the soil but only up to certain limits of supplementation. The results from this current study seem to contradict the belief that wild vegetables have the inherent ability to concentrate mineral micronutrients in their tissue. Factors such as environment, anti-nutrients, dietary diversity, plant parts, plant age, and varieties result in differences in reported nutritional composition of indigenous vegetables. Post-harvest handling, storage, cooking and preservation also alter the composition. The need to optimise protocols for each vegetable type and for different laboratories makes analysis expensive. Equipment and methods of analysis are varied and may not be comparable, making it difficult to generalise on the composition of these vegetables. The Agricultural Research Council of South Africa and other stake holders are conducting studies on some aspects of these vegetables. There are still many information gaps regarding many aspects of these vegetables which require research attention. These include; the selection and improvement of genotypes, seed biology and germination studies, agronomic (population, fertiliser, crop mixtures) studies and phyto-chemical evaluation of these important species in order to encourage the overall use of these important indigenous resources. Finally, there is need to promote their increased utilisation. / AFRIKAANSE OPSOMMING: Suid- Afrika is ryk aan biodiversiteit waaronder half-mak groente spesies, wat as wilde of inheemse groente bekend is, voorkom. Hierdie wilde inheemse groente is aangedui om goed in voedingswaarde te wees met voldoende makro-en mikrovoedingstowwe. Daar is egter nogsteeds 'n hoë voorkoms van wanvoeding, veral tekorte aan mikronutriënte onder die lae of marginale inkomstegroep van die bevolking. Die gebruik van inheemse groente word voorgestel as deel van die oplossing van die probleem van wanvoeding onder hierdie bevolkings. Inheemse groente is 'n belangrike bron van voedsel in die mielie gebaseerde bestaansboerdery sektor van landelike Suid-Afrika. Hul vernaamste rol is as smoor waar dit gebruik word tesame met stapelvoedsel in ʼn graan-gebaseerde dieet. Hierdie groentes was oor die algemeen ook aangedui om ryk te wees in mikrovoedingstowwe. Hoewel hulle verteer kan word in klein hoeveelhede, beïnvloed hulle die inname van graan stapelvoedsel, en speel 'n sentrale rol in huishoudelike voedselsekuriteit vir die armer landelike groepe. Vermenging van verskeie inheemse groente spesies in een maaltyd dra by tot die dieet diversiteit in terme van meer groentesoorte sowel as in terme van die keuse van smaak. Vir 'n paar baie arm gesinne is inheemse groentes die plaasvervanger vir gewone groente gewasse. Die seisoenale voorkoms van hierdie groente laat baie gesinne sonder 'n bron van voedsel gedurende die af-seisoen. Inheemse groente verhoog landbou-biodiversiteit op ʼn huishoudelike vlak . Hierdie landbou-biodiversiteit help buffer teen die opbou en vermeerdering van peste en siektes en bied belangrike dekking vir die grond. Verdere navorsing op akkerbou-, maatskaplike en ekonomiese aspekte is nodig om die rolle van inheemse groentes in bestaansboerdery in Suid-Afrika te verstaan. Die studie opname het getoon dat inheemse groente belangrik was in die dieet van die meeste mense van die platteland in die studie area. Hierdie groentes was gebruik as smoor hoewel hulle nie gekweek word nie. Hul metode van verkryging is deur dit te versamel van huise en die natuur. Die groentes word ook as medisinaal beskou. Die plaaslike benaming van wilde groente het gewissel tussen dorpe in dieselfde distrik, tot so 'n mate dat die benaming van groente tussen dorpe verskil. Hulle was na bewering volop in die somer, en daar was 'n afname in die beskikbaarheid af-seisoen, wat kwesbare mense, wat staatmaak op hul voorkoms, met 'n tekort aan kos laat. Die benutting van wilde groente onder Suid-Afrikaners daal as gevolg van die afhanklikheid in nuwe spsies. Pogings om te mak en wilde groente te kweek, kan belemmer word deur verskeie faktore, insluitend saaddormansie en voortydige blom. In hierdie studie was dormansie waargeneem in C. olitorius. Die reaksie van wilde genotipes van C. olitorius met verskillende saad groottes op verskeie droë hitte en warm water behandelings, was geëvalueer. Sade was geweek in kookwater ( 95oC ) vir tien sekondes en ander in 'n warm water bad by 80oC vir tien minute, en het gelei tot die hoogste reaksie op ontkieming in hierdie spesie. Die studie het ook belangrike interaksies tussen hitte behandeling en saad groottes getoon. Ons het tot die gevolgtrekking gekom dat C. olitorius sade van verskillende groottes diverse duur van blootstelling vereis en ook so m.b.t. die ondeurdringbare saadhuid. Cleome gynandra is nog 'n spesie wat as 'n groente in verskeie dele van die wêreld, insluitend Afrika verbruik word. Die plant word ook gebruik as 'n medisinale plant vir die behandeling van verskeie siektes van die mens. Onder die wilde groente, was C. gynandra aangedui om vroeg te blom, 'n verskynsel wat bekend staan as “bolting” en is algemeen in baie groente gewasse. Voortydige blom (vas) kan wees as 'n reaksie op die temperatuur uiterstes en fotoperiode en raak ook baie ander groen groente soos blaarslaai (Lactuca sativa) , spinasie (Spinacea oleracea) en mosterd (Brassica juncea ) . “Bolting” lei ook tot produksie verliese in blaar groentegewasse as hulle blom voordat hulle 'n ekonomiese opbrengs opgelewer het. Die verwydering van blomme en stikstof toediening het gelei tot 'n aansienlike toename in die vars en droë gewig van Cleome blare. Verwydering van blomme het gelei tot 'n toename van 46% in vars gewig van die blare. Die waargenome positiewe reaksie van die blaar opbrengs deur verwydering van blomme bied 'n moontlike manier om die “bolting” probleem te hanteer. Die voortdurende verwydering van die blomme lei tot verhoogde bruikbare blaar opbrengs. Die toepassing van toenemende stikstof topbemesting het verhoogde blaar opbrengs in C. gynandra tot gevolg. Die reaksie van geselekteerde inheemse groente (Corchorus olitorius en Amaranthus spp ) met mikrovoedingstowwe toegevoeg tot die grond, is in vergelyk met die reaksie van 'n verwysings gewas; spinasiebeet (Beta vulgaris var cicla . ). Vir al die vlakke van mikronutriente toegepas, was die spinasiebeet opgehoopte Cu , Zn en Mn in die blare, in beduidend (p <0.01 ) hoër konsentrasies as die wilde groente.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Gully erosion is a major environmental problem not only having direct influences on site but also indirect influences felt further down the catchment. Combating gully erosion has proven to be elusive due to the difficulty in finding the causal factors and developing mechanisms involved. Soil is the medium in which gully erosion occurs yet few research have investigated it as a driving factor behind gully development and those that have has done it in a very elementary way. The first aim of this project was to physically and chemically characterise and classify the discontinuous gully system at Malansdam to establish the relationship between landscape hydrology and geomorphologic gully development with a focus on control factors. This was done by field observations, physical measurements and spatial and hydrological analyses with a Geographical Information System (GIS). The Malansdam gully system was the first ever recorded Strahler stream order (SSO) 5 classical gully system with the most active region being in the upper reaches where a steeper slope is experienced. Although piping was observed the V-shape channels and SAR data from traditional wet analysis indicated runoff to be the dominant formation process. A duo of factors, consisting of one anthropogenic and one natural factor respectively, was found that the major control factors behind the gully formation. A unique anthropogenic factor that has never been published beforehand was found to be the anthropogenic driving factor namely the ploughed contour cultivation technique employed by the farmers in the Sandspruit catchment. The ploughed contours act as channels firstly collecting and secondly moving water that would have drained naturally downwards in the valley to one exit point in the gully system. This allows increased erosive energy because of the larger volumes of water entering one single point in the upper reaches of the gully system where a steeper slope is experienced. The driving factor in the natural group was determined to be weak soil structure due to an abundant amount of exchangeable Mg2+ cations occupying the exchange sites on the clay fraction. This would cause soil to disperse in the presence of water even with a low amount of exchangeable Na+. Combat methods would accordingly exist in the form of rectifying the soil structure and finding an alternative to the ploughed contour system currently employed, but also planting vegetation especially grass or wheat in the gully channels. The second aim of this project was to determine the capability of Near Infrared (NIR) spectrometry, with wavenumbers 12 500 – 4 000 cm-1, to predict indicators used in soil science to establish the dispersive nature of a soil. These indices included the Exchangeable Sodium Percentage (ESP), Sodium Absorption Ratio (SAR), Magnesium Saturation Percentage (MS%), Electrical Conductivity (EC), Potential Hydrogen (pH) as well as the four main exchangeable cations namely calcium (Ca2+), potassium (K+), sodium (Na+) and magnesium (Mg2+). Surface and subsurface soil samples were collected from active gully heads. These samples were minimally pre-processed thus only dried, milled and sieved. Thereafter it was subject to NIR analysis making use of the Bruker multi-purpose FT-NIR Analyser (MPA; Bruker Optik GmbH, Germany) with a spectral range of 12 500cm-1 to 4000cm-1 which is. Partial Least Square Regression (PLSR) models were built for each index and the exchangeable cations making use of QUANT 2 utility of OPUS 6.5 (MPA; Bruker Optik GmbH, Germany) software. Five different regrssion statistics namely the coefficient of determination (r2), Root Mean Square Error of Cross Validation (RMSECV), Ratio of Performance to Deviation (RPD), Bias and the Ratio of Performance of Quartiles (RPIQ) were used to assess the legitimacy of each PLSR model. Upon validation all the PLSR models performed in line with previously published work and in certain cases better. The only exception was MS% which would require further investigation. NIR thus possess the capability to predict a soil’s dispersive nature in a fast, reliable, inexpensive and non- destructive way, thus implying whether or not it contributes to gully erosion at a significant level or only minimally. / AFRIKAANSE OPSOMMING: Donga erosie is 'n groot omgewingsprobleem. Dit het nie net ‘n direkte invloed op die area waar dit geleë is nie, maar het ook ‘n indirekte invloed wat elders in die opvangsgebied ervaar word. Bekamping van donga erosie is moeisaam aangesien die faktore wat aanleiding gee tot die vorming en dryf daarvan moeilik is om te bepaal. Grond is die medium waarin erosie plaasvind, maar daar is nogtans steeds min navorsing wat grond ondersoek het as ‘n moontlike faktor aanleiding gee tot donga erosie. Die wat dit al wel ingesluit het, het dit slegs op n baie elemntêre manier ondersoek. Die eerste doel van hierdie projek was om die diskontinue donga stelsel fisies en chemise te karakteriseer en klassifiseer om soedoende die verhouding tussen die landskap hidrologie en geomorfologiese donga ontwikkeling te bepaal met n fokus op die faktore wat dit dryf. Dit was gedoen deur middel van observasies gedoen terwyl veldwerk uitgerig was, fisiese metings asook ruimtelike en hidrologiese analises deur gebruik te maak van n Geografiese Inligting Stelsel (GIS). Die klassieke Malansdam donga stelsel is ‘n Strahler stroomorde (SSO) van 5 toegeken en is die eerste een ooit wat dit behaal het. Die mees aktiefste area was in die bolope waar die steilste helling ervaar was. Alhoewel ondergrondse pyp formasie waargeneem was het die V-vormige donga kanale en SAR data van die tradisionele nat analise aangedui dat afloop die dominante vorming proses was. Daar was gevind dat 'n duo van faktore, wat bestaan uit een menslike en een natuurlike faktor onderskeidelik, die faktore was wat donga ontwikkeling in die area dryf. 'n Unieke menslike faktor wat nog nie vantevore gepubliseer is, was bevind as die menslike faktor wat aanleiding gee tot donga erosie. Hierdie faktor is die bewerkiingsmetode wat in die Sandspruit opvangsgebied gebruik word naamlik geploegde kontoerbewerking. Die geploegde kontoere tree op as kanale om eerstens water te versamel en tweedens om die vloeirigting daarvan te wysig. Water wat onder natuurlike toestande afwaarts sou dreineer tot in die vallei word vasgevang deur die kontoere en gekanaliseer na een invloei punt in die donga. Hierdie proses verhoog die erosiekrag van die water aangesien groter volumes by 'n enkele punt in die steiler bolope van die donga stelsel invloei. Die dryf faktor in die natuurlike groep was swak grond struktuur. Die oorsaak hiervan was die besetting van ‘n grootmaat uitruilbare Mg2+ katione op die uitruil plekke van die kleifraksie. Dit sou veroorsaak dat grond in die teenwoordigheid van water maklik sou dispergeer, selfs in die teenwoordigheid van 'n lae hoeveelheid uitruilbare Na+ katione. Metodes om donga erosie te bekamp sal dienooreenkomstig bestaan uit die herstel van die grondstruktuur en die toepassing van 'n alternatiewe gondbewerkings stelsel. Die aanplanting van plantegroei, veral gras en koring binne die donga kanale sal verder help met die veg tot bekamping Die tweede doel van hierdie projek was om te bepaal indien naby infrarooi (NIR) spektrometrie (met golfnommer van 12 500 – 4 000cm-1) oor die vermoë beskik om aanwysers wat traditioneel in grondkunde gebruik word om die dispergering van grond te meet te voorspel. Hierdie aanwysers sluit vyf indekse in naamlik die Veranderlike Natrium Persentasie (ESP), Natrium Absorpsie Verhouding (SAR), Magnesium Versadiging Persentasie (MS%), Elektriese Geleidingsvermoë (EC) en die Potensiële Waterstof (pH) sowel as die vier hoof uitruilbare katione naamlik kalsium (Ca2+) , kalium (K+), natrium (Na+) en magnesium (Mg2+). Oppervlak en ondergrondse grondmonsters is ingesamel by die punt van oorsprong by aktiewe dongas. Hierdie monsters is minimaal voorberei, dus slegs gedroog, gemaal en gesif. Daarna was dit onderworpe aan die NIR analise. Die Bruker meerdoelige FT-NIR Analiseerder (MPA; Bruker Optik GmbH, Duitsland) met 'n spektrale omvang van 12 500cm 1 4000cm-1 is hiervoor gebruik. Parsiële kleinste kwadraat regressie (PLSR) modelle is gebou vir elke indeks asook die uitruilbare katione deur gebruik te maak van die nutsprogram Quant 2 van die OPUS 6.5 (MPA; Bruker Optik GmbH, Duitsland) sagteware. Vyf verskillende regressie statistieke naamlik die bepalingskoëffisiënt (r2), vierkantswortel fout tydens kruis validasie (RMSECV), verhouding van prestasie teenoor voorspellingsafwyking (RPD), sydigheid en die verhouding van prestasie van kwartiele (RPIQ) was gebruik om die geldighied van elke PLSR model te asseseer. Alle PLSR modelle het goed presteer, behalwe vir MS% wat verdere navorsing vereis. NIR beskik dus oor die vermoë om die aard van dispergering van grond te bepaal op 'n vinnige, betroubare, goedkoop en nie afbrekende manier. Dit kan dus effektief aangewend word as ‘n substitusie vir die traditionele metodes om te bepaal as grond a beduidende faktor is of nie.

Thesis (PhD (Geography and Environmental Studies))—Stellenbosch University, 2008. / GIS has revolutionized geographic analysis and spatial decision support and has greatly enhanced our understanding of the real world though it’s mapping and spatial modelling capabilities. Although GIS software is becoming more powerful, less expensive and more userfriendly, GIS still remains the domain of a selected few who can operate and afford these systems. Since the introduction of web mapping tools such as Google Earth, accessibility to geographic information has escalated. Such tools enable anyone with access to a computer and the Internet to explore geographic data online and produce maps on demand. Web mapping products have, however, a very narrow range of functionality. In contrast to GIS that focuses on spatial data capture, storage, manipulation, analysis and presentation, the function of web mapping tools is to visualize and communicate geographical data. The positive impact of web mapping tools suggests, however, that GIS has not yet developed to a level where anyone can use the technology to support spatial decisions and enhance productivity. A possible solution is to close the functional gap between web mapping tools and GIS to make spatial analysis more accessible, thereby promoting geographical awareness and supporting better spatial decisions.

Thesis (DPhil (Geography))--University of Stellenbosch, 1967. / 368 leaves printed on single pages, preliminary pages i-v and numbered pages 1-338. Includes bibliography, list of figures. / Digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner.