Academic literature on the topic 'Oenology and viticulture'

Today, the viticulture and oenology sector in Georgia has a fair potential for development. According to the statistical data, the income from the wine production is growing year by year for the country. Maintaining the growing potential of productivity in the viticulture and oenology sector is linked to the stable quality of grape and wine. The skilled workforce represents one of the essential components for ensuring production of high-quality products. Vocational trainings can provide both, the prospective and existing employees of the viticulture and oenology sector with the possibility to develop necessary skills. Moreover, each country has its own unique cultural, economic and social aspects that have to be taken into consideration in the process of assessing and reforming the country's educational potential. Numerous countries rely on the "mixed systems" that combine different types of work-based learning, including school-based vocational education and dual vocational education programs. However, in view of international best practice, dual programs are considered to be the best mode of instruction for vocational programs in the direction of viticulture and oenology. Introduction of work-based learning with the so called dual vocational education programs by the state in recent years, can be considered as a step forward in this direction. Also, the state offers short-term vocational education programs within the framework of close cooperation with the private sector. The viticulture and oenology sector is the first, together with the tourism sector, to be recognized as a priority by the state, therefore the training of students with dual vocational education programs has been piloted. In summary, for a vocational student, dual vocational education programs involve pursuing studies at a vocational education institution, where a student takes a theoretical course on a future profession, as well as a practical course necessary for acquiring practical and technical skills for the profession. This form of teaching provides more opportunities for deepening the public-private partnerships in education. On the one hand, it helps to reduce budgetary expenditures of the state and, on the other hand, allows the system to receive additional financial as well as intangible benefits. The interest of the private sector to participate in the educational process is multifaceted. However, one of the main reasons for the interest is possibility to hire experienced workforce in the future. Increasing the private sector involvement and delegating responsibilities to the private sector by the state represents a good opportunity to train/retrain qualified staff. This factor can be considered as a prerequisite for matching workforce demand and supply on the labor market. Training of highly qualified staff guarantees reduction of unemployment and poverty and ensures sustainable economic development of the country. Keywords: vocational education, dual vocational education programs, work-based learning, viticulture and oenology sector.

Biodynamics, as a viticultural method, is generally not well understood by either its practitioners or its detractors. Detractors complain that biodynamics is rooted in mysticism and has no scientific basis whatsoever and thus no place in the increasingly scientific world of viticulture and oenology. Proponents counter that the biodynamic method established by Rudolf Steiner in the early twentieth century is fundamentally based on scientific facts, and that the results of applying the method are consistent and easily discernible in both the vineyard and the wine glass. This article elucidates the very complex relationship between Steiner's theory and reductivist science and suggests that only by better understanding this relationship can we truly appreciate what the biodynamic method is.

Turkey is an appropriate country for viticulture due to its favourable climatological characteristics. Although Turkey produces plenty of grapes in the fertile soil and is one of the world's leading countries in terms of vineyard area, it is known that only 11% of the grapes produced are used in wine production. The difficulties encountered at every stage of the wine sector in Turkey are reflected in oenology education briefly defined as the science of wine and it is observed that the number of schools training qualified personnel in the field of wine is low. However, Turkey's closest rivals in terms of vineyard area and production quantities of grapes take place on the European continent where the situation is quite different. In these countries, the education of oenology is of great importance, and those who have completed the oenology education are given the title of oenologist. The purpose of this study prepared with content analysis method was to compare the oenology education in Turkey to oenology education in Europe and put forward some suggestions for oenology education in Turkey. As a result of the study, the following conclusions have been reached: Oenology education in Turkey is a neglected area of study for a lot of different reasons, oenology education is not given at undergraduate, graduate, and doctoral levels, and wine production technology education is given only in one state university at the associate's degree level. It is thought that the study will contribute to the literature, next researchers, the wine sector, and especially the institutions that provide education on wine.

Over time at Research and Development Stationfor Viticulture and Oenology Odobeşti, numerous intra- and interspecific sexual hybridizations have been carried out, in order to obtain new cultivars, with high productive and qualitative potential, with disease tolerances, resistant to stress factors, very well adapted to the climatic conditions specific to Vrancea vineyards.Thus, valuable hybrid elites were obtained, which represent a permanent source for the selection, approval and promotion of new grape cultivars. In order to evaluate the agrobiological and technological potential of some valuable hybrid elites, in the period 2016 - 2018, two elites were studied: ‘E.H. 10-1-6’ and ‘E.H. 6-1-1’. The results obtained from this study showed that these hybrid elites have a high productive and qualitative potential, show high biological resistance to the main diseases of the vine, and can be proposed for approval in order to improve the national assortment, in the context of sustainable viticulture.

Assessing sustainability of the wine industry requires improved characterization of its environmental impacts, namely in terms of water use. Therefore, quantification of water inputs and wastewater (WW) outputs is needed to highlight inefficiencies in wine production and related consequences for the environment. Water use and WW generation in irrigated viticulture and oenology remains insufficiently quantified for dry Mediterranean regions (e.g. South Portugal). This paper is focused on wine production under warm and dry climate conditions in the winegrowing region of Alentejo (South Portugal). This region experiences increasingly dry conditions, while the irrigated area keeps expanding, which puts exacerbates the pressure on existing local and regional water resources. Additionally, more erratic variation in climate conditions and the tendency for increasingly extreme climate events (e.g. heat waves) pose more challenges to Alentejo’s wine sector. We conclude that quantitative information on water use and management is not always easy to obtain or access, which hinders improved strategies and/or policies for water use at farm, winery and region-level. Up-to-date statistics and robust metrics can help to better characterize water use and WW flows for Alentejo’s wine region, while optimizing management in vineyards and wineries, in companies and region-wide. The paper is focused on a “Farm-Winery” scenario, which is the most common in South Portugal’s wine sector

The experience was carried out with the students of the optional subject “Wine and Health”, taught in 4th year of Degree of Oenology. This Degree has a low number of students, due to that, in the first year of teaching (2013/14) only three students enrolled in the subject, so we considered it was necessary to do something “different” to motivate students to enroll in this subject. This was carried out by inviting them to do a literature review on some topics, such as the relationship between moderate wine intake and Alzheimer’s, Parkinson’s, Cancer or Allergy. In addition, they had to make an audiovisual presentation and expose it in the Conference of Viticulture and Oenology that are celebrated in Almendralejo (Badajoz, Spain), every year at the beginning of May. In general, after five years it has been observed that this methodology has increased the interest of students for this subject, which is reflected in more students in class, more class attendance and great interest. In addition, they have developed transversal skills such as public speaking, which has provided them with security and will probably be useful when conducting job interviews.

The State Institute of Viticulture and Oenology (WBI) Freiburg Germany has been breeding disease-tolerant grape varieties (Piwis) since the 1930s. Since that time, 15 fungus-resistant white and red wine varieties and 4 table grape varieties have been cultivated. All these grape varieties are approved as Vitis vinifera. Until now, fungus resistance has been the focus of breeding work. Due to climate changings, it will be necessary in future to delay budding and ripening of grapevines. This would protect the vines from late frosts in spring and delay the ripening of the berries in autumn. In addition, the loosening of the grape structure and dry resistance will be future breeding goals. To improve the resistance and a later ripeness of the berries, new grape varieties which are currently being tested have been developed in cooperation with the INRA in Colmar (France).

Thesis (MScAgric (Viticulture and Oenology))--Stellenbosch University, 2008.
The production of good quality wine is essential to ensure competitiveness on an international level. Wine quality is usually evaluated for the visual, olfactory and taste characteristics of that specific wine. The winemaking process starts with the grapes in the vineyard followed by oenological practises in the winery until the final wine is bottled. Factors that could influence wine quality include the grape quality from which the wine is made and different techniques used during wine production. Other factors include the presence as well as the interaction between microorganisms found in the grape juice and wine, and the biochemical effect these microorganisms have on certain chemical compounds in the wine. The different microorganisms found in grape juice and wine can either have a negative or positive contribution to the final quality of the wine. During certain stages of the winemaking process the growth and metabolic activity of certain microorganisms is a necessity to produce good wine. During other stages the presence of certain microorganisms can lead to the development of compounds that is regarded as off-flavours and therefore lead to unpalatable wines of low quality. Yeast strains that naturally present on the grapes and in the winery can also contribute to the final quality of the wine. Brettanomyces yeasts are part of the natural flora of winemaking and can drastically influence the aroma characters of a wine through the production of volatile phenols. The general aroma descriptions of volatile phenols include "smoky", "spicy", "barnyard", "animal" and "medicinal". Although some wine drinkers believe that these characters can add to the complexity of a wine, high levels of volatile phenols is mostly regarded as off-flavours and mask the natural fruity flavours of a wine. With this study we wanted to generate a better understanding of the effect of different winemaking practises on the production of volatile phenols by B. bruxellensis. We evaluated the difference in volatile phenol production when B. bruxellensis was introduced before or after alcoholic fermentation. We have shown that B. bruxellensis could grow and produce volatile phenols during alcoholic fermentation. Results obtained also showed that commercial wine yeast strains could produce the vinyl derivatives that serve as precursors for Brettanomyces yeast to produce the ethyl derivatives. The commercial yeast strains differed in their ability to produce vinyl derivatives. Different malolactic fermentation scenarios were evaluated, namely spontaneous versus inoculated, and with or without yeast lees. Results showed that spontaneous malolactic fermentation had higher volatile phenol levels in the wine than inoculated malolactic fermentation. The treatment with lees reduced the level of volatile phenols, probably due to absorption by yeast cells. The presence of the phenyl acrylic decarboxylase (PAD1) gene and the production of volatile phenols by S. cerevisiae commercial yeast strains were evaluated in Shiraz grape juice and in synthetic grape juice. The results indicated that the yeast strains differ in their ability to produce 4-vinylphenol and 4-vinylguaiacol. All the yeast strains tested had the PAD1 gene. We also evaluated the presence of the phenolic acid decarboxylase (padA) gene and the ability of different lactic acid bacteria strains to produce volatile phenols in synthetic wine media. Although some of these strains tested positive for the phenolic acid decarboxylase gene most of them only produced very low levels of volatile phenols. This study made a valuable contribution on the knowledge about the effect of Brettanomyces yeast on the volatile phenol content of red wines during different stages of the winemaking process and when applying different winemaking practices. It also showed the effect between Brettanomyces yeast and other wine microorganisms and the possible influence it could have on the final quality of wine. Research such as this can therefore aid the winemaker in making certain decisions when trying to manage Brettanomyces yeast spoilage of wines.

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: Because of long-term climate changes, apparently associated with higher temperatures and fewer rainfall events, factors such as water-use efficiency and site selection for new cultivars are a matter of increasing importance for viticulture. Within this context, the root system is expected to play a key role. Its relevance to grapevine functioning is due to the numerous functions in which it is involved. In the light of this, the development of the root system is highly relevant to the viticulturist because of the fact that grapevine growth and functioning are dependent on the development of the root system. Differences can, therefore, be expected in terms of berry ripening on single grapevines of the same scion for situations with differing development of root systems, despite being grafted on the same rootstock. Root growth is influenced by several factors, among the ecological aspects. Soil parameters have a predominant influence on root growth and distribution but also annual root production can be altered by canopy manipulation. Due to the importance of root growth to the aboveground development of the vine, it is critical to gain understanding of the relationship between soil factors and root growth and distribution, and the central role that the subterranean environment plays in the concept of terroir. This study aimed to investigate the effect of selected soil physical and chemical parameters on root growth and distribution and to investigate whether having very different canopies influences root growth. In order to achieve these goals, two experiments were conducted; the first was performed in two commercial Sauvignon blanc vineyards each grafted onto Richter 110, non-irrigated, with two treatments: undisturbed lateral growth and complete lateral removal. The second study included the analysis of eight commercial Sauvignon blanc vineyards grafted onto Richter 99 and Richter 110 located in the Stellenbosch Wine of Origin District. Measurements of physical and chemical soil parameters, root growth and distribution, canopy growth and functioning, vine water status and berry composition were performed. The edaphic factors appeared to be one of the most important parameters that affected root development by changing soil water availability and possibly causing physical or chemical limitations on root growth. From the results of this study, it is clear that severe water stress and a pH (KCl) lower than 4.5 play a key role in the limitation of root growth. Due to the fact that most of the soils from the Stellenbosch Wine of Origin District, especially the subsoils, are acidic, this is a factor to consider before planting. On the other hand, the combination of favourable edaphic conditions, such as a subsoil pH of higher than 5.0, light- to mediumtextured subsoil and moderate water stress, allow increased growth of thin roots. However, the effect of canopy management on root growth cannot be discounted due to its importance in the variation of carbohydrate demand by competing sinks. This study showed that lateral removal done from when the berries are at pea size results in an increase in the number of thin roots (0.5-2.0 mm). The secondary leaf area represents at least the same leaf area as the primary leaf area in all the vineyards evaluated, which reveals the relative importance of the laterals in the total leaf area of the vine and the potential importance in terms of microclimate and leaf area available for photosynthesis. Studies of root growth should take the vineyard canopy architecture into account.
AFRIKAANSE OPSOMMING: As gevolg van langtermyn klimaatsveranderinge wat toegeskryf kan word aan die voorkoms van hoër temperature en laer reënval, is faktore soos effektiwiteit van waterverbruik en liggingseleksie vir nuwe kultivars van kardinale belang vir wingerdkunde. Binne hierdie konteks, speel die wortelsisteem ‘n belangrike rol. Die belangrikheid hiervan vir wingerdfunksionering kan toegeskryf word aan die talle funksies waarby dit betrokke is. Die ontwikkeling van die wortelsisteem is dus hoogs relevant vir die wingerdkundige, omdat wingerdgroei en funksionering afhanklik is van die ontwikkeling van die wortelsisteem. Verskille kan daarom dus verwag word in terme van korrelrypwording op ‘n enkele wingerdstok van dieselfde onderstok vir gevalle met verskillende ontwikkeling van die wortelsisteem, ten spyte daarvan dat dit op dieselfde onderstok geënt is. Wortelgroei word, onder ekologiese aspekte, deur verskillende faktore beïnvloed. Grondfaktore het meerendeels ‘n predominante invloed op wortelgroei en -verspreiding, terwyl jaarlikse wortelproduksie deur lowermanipulasie beïnvloed kan word. Weens die belangrikheid van wortelgroei vir die bogrondse ontwikkeling van die wingerd, is dit krities om kennis op te doen oor die verhouding tussen grondfaktore en wortelgroei en –verspreiding, asook die sentrale rol wat die subterreinomgewing op die terroir-konsep speel. Die studie was daarop gemik om die invloed van geselekteerde fisiese en chemiese parameters van grond op wortelgroei en -verspreiding vas te stel, en ook te ondersoek of verskillende lowers wortelgroei sal beïnvloed. Om laasgenoemde doelwitte te bereik, is twee eksperimente uitgevoer. Die eerste is uitgevoer in ‘n kommersïele Sauvignon blanc-wingerd wat geënt is op Richter 110, sonder besproeïng en met twee behandelings, naamlik onversteurde sêkondere lootgroei en volledige sêkondere lootverwydering. Die tweede studie het die analise van agt kommersïele Sauvignon blancwingerde geënt op Richter 99 en Richter 110 in die Stellenbosch Wyn van Oorsprong Distrik. Metings van fisiese en chemiese grondfaktore, wortelgroei en -verspreiding, lowergroei en -funksionering, plantwaterstatus en korrelsamestelling is uitgevoer. Dit blyk dat edafiese faktore een van die belangrikste parameters is wat wortelontwikkeling beïnvloed deur beskikbaarheid van grondwater te verander, en wat moontlik fisiese en chemiese beperkings op wortelgroei kan veroorsaak. Uit die resultate van die studie is dit duidelik dat intense waterspanning en ‘n pH (KCl) laer as 4.5 ‘n belangrike rol in die beperking van wortelgroei speel. Aangesien die meeste van die grondsoorte in die Stellenbosch Wyn van Oorsprong Distrik, veral al die subgronde, suur is, is dit ‘n faktor wat in oorweging geneem moet word voor aanplantings. Die kombinasie van gunstige edafiese toestande, soos ‘n subgrond met ‘n pH hoër as 5.0, ‘n lig tot medium tekstuur en matige waterspanning, sal dus aanleiding gee tot ‘n toename in die groei van dun wortels. Die effek van lowerbestuur op wortelgroei kan egter nie buite rekening gelaat word nie weens die belangrikheid daarvan in die variasie van koolhidraataanvraag deur kompeterende vraagpunte. Hierdie studie toon dat, indien sêkondere lootverwydering tydens ertjiekorrelgrootte toegepas is, dit aanleiding gee tot ‘n toename in die dun wortels (0.5 tot 2.0 mm). Die sêkondere blaaroppervlakte verteenwoordig minstens dieselfde blaaroppervlakte as die primêre blaaroppervlakte in al die wingerde wat ondersoek is, wat dui op die belangrikheid van sêkondere lote in die totale blaaroppervlakte van die wingerd en die potensiële belangrikheid daarvan in terme van mikroklimaat en blaaroppervlakte wat vir fotosintese beskikbaar is. Studies van wortelgroei moet lowerargitektuur in ag neem.

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2006.
The quality of wine is influenced by numerous factors of which the grapes, winemaking techniques and effective quality control are to name a few. The use of new techniques should be cost effective and always have a positive influence on the wine quality. The addition of commercial tannins to wine is a fairly new technique and the effects of these additions at the concentrations prescribed have not been investigated in detail. The commercial tannins can be added to wine for different reasons, which may include: stabilisation of colour, increasing the aging potential, to modify aromas, promote precipitation of proteins, limit the effect of laccase activity, substrate for micro-oxygenation, to act as a redox buffer and structural and mouth feel modification. The reason for the addition determines the type of commercial tannin that is used, the timing of the addition and the dosage used.

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: Previous research has shown that carotenoids are precursors of C13-norisoprenoid aroma compounds in wine. C13-norisoprenoids have low threshold values in wine with the most prominent C13-norisoprenoids being β-damascanone and β-ionone which contribute honey and floral like aroma to wine. Chlorophyll and its derivates have also been detected in wine with potential to be precursors to aroma compounds. Apart from the contribution of these pigments to wine aroma and quality they are vital role players in photosynthesis and are widely found in plants and plant products. The main functions of these pigments in plants are light collection and light-protection. Research has shown that environmental conditions, climate, light exposure of bunches and soil water deficit influence the carotenoid content of grape berries. Furthermore the concentration of carotenoids and chlorophylls has also been shown to differ between cultivars. No research in this regard has been done on Merlot grape berries. With this in mind, the aim of this study was to evaluate the effect of vigour and soil water content on the evolution of carotenoids and chlorophylls through ripening of grape berries from the cv. Merlot. However, when looking at methods to analyse carotenoids and chlorophylls in berry tissue, especially lyophilised tissue, there were no readily available methods. Thus, an extraction method to identify and quantify the carotenoid and chlorophyll profile of lyophilised tissue from unripe (green) to ripe (red) Merlot grape berries was needed. In this study the RPHPLC method of Taylor et al. (2006) for carotenoids and the extraction method of Mendes-Pinto et al. (2004) were adapted to analyse both carotenoids and chlorophylls in lyophilised grape tissue. The RP-HPLC method baseline separated all the carotenoids and chlorophylls and their derivatives. Recovery of standards from mock extractions was high, indicating that the extraction procedure was acceptable. However, extraction recovery tested in the matrix of the grape tissue showed less promising results due to the high acid content of grape tissue. Violaxanthin, neoxanthin and the chlorophylls were especially sensitive to low pH conditions which facilitated their degradation. The degradation products of these compounds under acidic conditions were identified as pheophytin a, b, chlorophillide a, pyropheophytin b, cisviolaxanthin, cis-neoxanthin, neochrome, mutatoxanthin and luteoxanthin. There is a possibility that some degradation products were already present in the tissue due to lyophilisation (since the water in the berry was then removed and the acid concentrated). More work is needed to investigate the effect of lyophilisation and storage on the composition of grape tissue of different maturity. The extraction method for grape berry tissue at different ripening stages should also be optimised further to effectively neutralise tissue acidity, without compromising the extraction of carotenoids significantly, in especially green berry tissue. The question as to whether cisisomers and chlorophyll degradation products are naturally present in grape berries or are formed during sampling and processing remains unanswered in the current study. This study confirmed that in general carotenoids and chlorophylls decrease on a per berry (μg/berry) and concentration (μg/g) basis from veraison to harvest. Furthermore, this study was inconclusive in showing that vigour differences have an effect on the rate of synthesis/degradation of carotenoids, chlorophyll and some other ripening parameters, namely malic acid, total glucose and fructose, total tannin and total anthocyanin, from pre-veraison (pea size) to harvest. Additionally, no significant effect of soil water content on carotenoids, chlorophylls and ripeness parameters was found in this study, most likely due the fact that high soil water capacity was found in lower soil layers which may have prevented significant differences in grapevine water status. Experimental plots selected for vigour differences based on normalised difference vegetation index (NDVI) images, pruning mass and soil water measurements by means of a neutron probe, showed significant differences in soil water content in only the first 30 cm of the soil for the ripening seasons studied. Predawn plant water potential measurements, however, indicated that none of the experimental vines experienced severe water stress which was previously shown to effect carotenoid content of grapes. The carotenoid 5,8-epoxy--carotene was quantified for the first time in grapes and represents a significant amount of the total carotenoids present at harvest. All the carotenoids and chlorophylls except -carotene appeared to be sensitive to seasonal variation in climatic conditions. Lutein and β-carotene were found to be the most abundant carotenoids present in Merlot grape berries together with chlorophyll a for both seasons studied. The values of these carotenoids also correlated well with previous research. However, chlorophyll a was found in much larger quantities in Merlot berries compared to reported data. This is possibly because in this study the chlorophyll degradation products were included in the calculation of chlorophyll a. Multivariate analysis showed promising preliminary prediction models (with correlation values of above 0.8 for both seasons analysed) for the prediction of the concentration of ripeness parameters (glucose, fructose, malic acid, total tannins and anthocyanins) with carotenoid and chlorophyll content. This result highlights the opportunity for the development of a rapid non-destructive method to measure carotenoids and chlorophylls in berries which in turn can predict optimal ripeness. Furthermore, since carotenoids are the precursors to C13- norisoprenoid aroma compounds in wine a preview of the potential contribution of these aromas to wine might be evaluated. Further research is necessary to investigate the possibility of building and validating such models.
AFRIKAANSE OPSOMMING: Vorige navorsing het getoon dat karotenoïede die voorlopers is van C13-norisoprenoïed aromaverbindings in wyn. C13-norisoprenoïede het lae drempelwaardes in wyn, met β- damassenoon en β-jonoon as die prominentste C13-norisoprenoïede wat ‘n bydrae tot die heuning en blomagtige aroma van die wyn maak. Chlorofil en sy derivate is ook reeds in wyn bespeur, met die potensiaal om voorlopers van aromaverbindings te wees. Buiten die bydrae van hierdie pigmente tot wynaroma en -kwaliteit is hulle ook belangrike rolspelers in fotosintese en kom hulle wydverspreid in plante en plantprodukte voor. Die vernaamste funksies van hierdie pigmente in plante is om lig te versamel en om as beskerming teen lig op te tree. Navorsing het getoon dat omgewingstoestande, klimaat, ligblootstelling van die trosse en grondwatertekorte die karotenoïedinhoud van druiwekorrels beïnvloed. Verder is ook getoon dat die konsentrasie van karotenoïede en chlorofille tussen kultivars verskil. Geen navorsing is al in hierdie opsig op Merlot-druiwekorrels gedoen nie. Met hierdie aspek in gedagte was die doelwit van hierdie studie om die effek van groeikrag en grondwaterinhoud op die evolusie van karotenoïede en chlorofille tydens die rypwording van druiwekorrels van die cv. Merlot te evalueer. Wanneer mens egter kyk na die metodes waarvolgens die karotenoïede en chlorofille in korrelweefsel geanaliseer word, is daar geen geredelik beskikbare metodes nie. ‘n Ekstraksiemetode om die karotenoïed- en chlorofilprofiel van geliofiliseerde weefsel van onryp (groen) tot ryp (rooi) Merlot-bessies te identifiseer en kwantifiseer was dus nodig. In hierdie studie is die RP-HPLC metode van Taylor et al. (2006) vir karotenoïede en die ekstraksiemetode van Mendes-Pinto et al. (2004) aangepas om beide karotenoïede en chlorofille in geliofiliseerde druiweweefsel te analiseer. Die basislyn van die RP-HPLC metode het all karotenoïede en chlorofille en hul derivate geskei. Herwinning van die standaarde vanaf skynekstraksies was hoog, wat aandui dat die ekstraksieprosedure aanvaarbaar was. Ekstraksieherwinning wat in die matriks van die druiweweefsel getoets is, het egter minder belowende resultate getoon as gevolg van die hoë suurinhoud van die druifweefsel. Violaxantien, neoxantien en die chlorofille was veral sensitief vir toestande van lae pH, wat hulle afbreking gefasiliteer het. Die afbrekingsprodukte van hierdie verbindings onder suurtoestande is geïdentifiseer as feofitien a en b, chlorofillied a, pirofeofitien b, cis-violaxantien, cis-neoxantien, neochroom, mutatoxantien en luteoxantien. Daar is ‘n moontlikheid dat sommige afbreekprodukte reeds in die weefsel teenwoordig was as gevolg van liofilisering (aangesien die water in die korrel reeds verwyder was en die suur gekonsentreerd was). Meer werk is nodig om die effek van liofilisering en berging op die samestelling van druifweefsel van verskillende rypheid te bepaal. Die ekstraksiemetode vir druifkorrelweefsel op verskillende stadia van rypwording moet ook verder geoptimaliseer word om weefselsuurheid doeltreffend te neutraliseer, sonder om die ekstraksie van karotenoïede noemenswaardig te kompromitteer, veral in groen korrelweefsel. Die vraag of cis-isomere en chlorofil afbreekprodukte natuurlik in die druifkorrels teenwoordig is en of hulle tydens monsterneming en prosessering gevorm word, kon nie in hierdie studie beantwoord word nie. Hierdie studie het bevestig dat karotenoïede en chlorofille oor die algemeen op ‘n korrel (μg/korrel) en konsentrasie (μg/g) basis afneem vanaf deurslaan tot oes. Hierdie studie het nie daarin geslaag om te toon dat groeikragverskille vanaf voor-deurslaan (ertjiekorrelgrootte) tot oes ‘n effek het op die tempo van sintese/afbreking van karotenoïede, chlorofil en ander rypwordingsparameters nie, naamlik op appelsuur, totale glukose en fruktose, totale tannien en totale antosianien. Daar is ook in hierdie studie geen noemenswaardige effek van grondwaterinhoud op karotenoïede, chlorofille en rypheidsparameters gevind nie, heel moontlik as gevolg van die feit dat hoë grondwaterkapasiteit in die laer grondlae gevind is, wat betekenisvolle verskille in wingerdwaterstatus kon verhoed het. Eksperimentele persele wat gekies is vir groeikragverskille op grond van genormaliseerde verskil plantegroei indeks (NDVI) beelde, snoeimassa en grondwatermetings met ‘n neutronvogmeter het net in die eerste 30 cm van die grond noemenswaardige verskille in grondwaterinhoud getoon vir die rypwordingseisoene wat bestudeer is. Voor-sonopkoms plantwaterpotensiaalmetings het egter aangedui dat geen van die eksperimentele wingerdstokke ernstige waterstres ervaar het nie. Sulke stres is voorheen aangedui om ‘n effek op die karotenoïedinhoud van druiwe te hê. Die karotenoïed 5,8-epoksi--karoteen is vir die eerste keer in druiwe gekwantifiseer en verteenwoordig ‘n noemenswaardige hoeveelheid van die totale karotenoïede wat met oes teenwoordig is. Al die karotenoïede en chlorofille behalwe -karoteen blyk sensitief vir seisoenale verskille in klimaatstoestande te wees. Luteïen en β-karoteen was die volopste karotenoïede in die Merlot-druifkorrels, tesame met chlorofil a, vir beide seisoene wat bestudeer is. Die waardes van hierdie karotenoïede was ook goed gekorreleer met vorige navorsing. Chlorofil a is egter in baie groter hoeveelhede in Merlot-korrels gevind in vergelyking met dít wat in die data gerapporteer is. Die rede hiervoor is moontlik dat die chlorofil-afbreekprodukte in hierdie studie in die berekening van chlorofil a ingesluit is. Meerveranderlikeontleding het belowende voorlopige voorspellingsmodelle getoon (met korrelasiewaardes van meer as 0.8 vir beide die seisoene wat geanaliseer is) vir die voorspelling van die konsentrasie van rypheidsparameters (glukose, fruktose, appelsuur, totale tanniene en antosianiene) met karotenoïed- en chlorofilinhoud. Hierdie resultaat beklemtoon die geleentheid vir die ontwikkeling van ‘n vinnige, nie-destruktiewe metode om karotenoïede en chlorofille in korrels te meet, wat op sy beurt optimate rypheid kan voorspel. Aangesien karotenoïede die voorlopers van C13-norisoprenoïed aromaverbindings in wyn is, kan ‘n voorskou van die potensiële bydrae van hierdie aromas tot wyn moontlik verder evalueer word. Verdere navorsing is nodig om die moontlikheid van die bou en geldigheidsbepaling van sulke modelle te ondersoek.

MScAgric
ENGLISH ABSTRACT: The Little Karoo region of South Africa stretches from Montagu in the west, through Barrydale on the Langeberg Mountain, towards Ladismith, Calitzdorp, Oudtshoorn and De Rust in the east, with the Swartberg mountain range in the north. The Wine of Origin district of Calitzdorp is a small, demarcated area around Calitzdorp in the Little Karoo, surrounded by the Rooiberg, Swartberg and Kleinberg mountains. With a mean February temperature (MFT) of 23.7ºC and a low annual rainfall of 233 mm, the district of Calitzdorp has a similar climate to that of the Douro Demarcated Region (DDR). The MFT is comparable to the DDR mean July temperature, and it seems that the Douro Superior sub-region to the east of the DDR has a mean July temperature of higher than 25°C. In the Cima Corgo sub-region (in the centre of the DDR), and the Baixo Cargo sub-region, the mean July temperatures are ±25°C and ±22°C respectively. Annual rainfall in the DDR is much higher, with Baixo Cargo recording 1 018 mm, Cima Corgo recording 658 mm and Douro Superior in the east recording only 437 mm. Touriga Naçional is one of the highest quality Portuguese red grape varieties. It produces high-quality port-style wine as well as table wines. Excellent quality Touriga Naçional wines have a dark black/purple colour, good extract, high, elegant tannin content and intense aromas, with typical plum, raisin, wild fruit, mulberry, “fynbos” and cherry aromas. The most suitable terroir for Touriga Naçional in the DDR has been found to be on sites that restrain the natural vigour of the grapevine. Soils with moderate to low water-holding capacity, in association with low rainfall, result in water deficits during the growing season and are considered optimal to restrict growth vigour. A steep, northern middle slope is ideal in the southern hemisphere for high temperatures and sunlight interception. Warm temperatures (25 to 30 °C) during the day and cooler temperatures during the night are optimal for photosynthesis and colour development. In order to study factors affecting the quality of Touriga Naçional in Calitzdorp, two Vitis vinifera L. cv. Touriga Naçional commercial vineyards in the Calitzdorp district were selected. Each vineyard was divided into two separate management blocks based on their empirically determined quality of production. Two crop-reduction treatments, the standard 50% crop reduction (which was considered to be the control) and a further less drastic treatment of 25% crop reduction, were applied. Significant differences were found in viticultural performance between the two adjacent Touriga Naçional management blocks in each vineyard, especially with respect to vigour. The upper management blocks, which provided grapes for reserve-quality port-style wines, experienced a higher water deficit due to the moderate soil water-holding capacity and higher temperatures in comparison to the lower sites. The higher water deficits had a restraining effect on the Touriga Naçional vines, and therefore the upper sites had lower vigour, which contributed to better quality of both the wine and port-style wine, and this could be recognised sensorially. However, it was not reflected in the chemical analytical results. Crop load also appeared to have an effect on the Touriga Naçional grapevines, but this appeared to be dependent on the management block. The 50% crop reduction had a significant positive effect on the sensory analyses, but did not significantly affect the chemical analyses. Calitzdorp terroir has a similar effect on Touriga Naçional compared to the DDR terroir, and that is why Calitzdorp can produce good table and port-style wines from Touriga Naçional.
AFRIKAANSE OPSOMMING: Die Klein Karoo-streek in Suid Afrika strek vanaf Montagu in die weste, deur Barrydale teen die Langeberg, na Ladismith, Calitzdorp, Oudtshoorn en De Rust in die ooste, met die Swartberg in die noorde. Die distrik van Calitzdorp is ‘n klein area rondom Calitzdorp, in die Klein Karoo, wat deur die Rooiberg, Swartberg en Kleinberg omring is. Calitzdorp het ‘n gemiddelde Februarie-temperatuur (GFT) van 23.7°C en ‘n lae jaarlikse reënval van 223 mm, wat soortgelyk is aan die klimaat van die Douro Vallei in Portugal. Die Douro Vallei se gemiddelde Julie-temperatuur (GJT) in vergelyking met die GFT van Calitzdorp is hoër, met temperature van meer as 25°C in die substreek Douro Superior. Vir die substreke Cima Cargo en Baixo Cargo is die GJT ±25°C en ±22°C onderskeidelik. Die jaarlikse reënval is ook hoër by Baixo Cargo, met 1 018 mm, Cima Cargo met 658 mm en Douro Superior met slegs 437 mm. Touriga Naçional is een van die beste Portugese rooi kultivars wat hoëkwaliteit tafel- en portwyne produseer. ‘n Tipiese hoëkwaliteit Touriga Naçional-wyn het ‘n swartpers kleur, hoë ekstrak, hoë elegante tanniene en intense aromatiese geure wat tipiese pruim, rosyne, wilde vrugte, moerbei, fynbos en kersie aromas insluit. Die geskikste terroir vir Touriga Naçional is op swak gronde wat die natuurlike groeikrag van die wingerdstok strem. Gronde met matige tot lae grondwaterhouvermoë tesame met lae reënval veroorsaak ‘n waterstremming in die wingerdstok gedurende die groeiseisoen en word as optimaal beskou omdat dit beheersde groei veroorsaak. In die suidelike halfrond word relatief steil, noordelike middelhange as ideaal beskou vir hoë temperature en maksimale sonligonderskepping. Gepaardgaande hiermee is die interne dreinasie verantwoordelik vir vinniger uitdroging van die grond. Hoë temperature (25 tot 30°C) gedurende die dag en koue nagte is optimaal vir fotosintese en kleurontwikkeling. Twee Vitis vinifera L. cv. Touriga Naçional kommersiële wingerde in die Calitzdorp-distrik is geselekteer en in twee afsonderlike bewerkingsblokke verdeel, gebaseer op kwaliteitsverskille. In elke blok was die verdeling van so ‘n aard dat daar ‘n hoërliggende helfte en ‘n laerliggende helfte was. Twee trosverminderingsbehandelings, nl. 50% (kontrole) en 25%, gebaseer op trosgetalle, is toegepas. By elkeen van die wingerde was daar betekenisvolle groeiverskille tussen die twee aangrensende helftes. Die boonste helftes (of gedeeltes) het minder gegroei a.g.v. ‘n hoër waterstremming sowel as hoër temperatuur as die laer helftes. Dit het geblyk om ‘n positiewe invloed op die kwaliteit van beide die tafel- en portwyne uit te oefen. Troslading het ook ‘n effek op die Touriga Naçional-wingerde gehad, maar dit blyk of dit blok-afhanklik is. Die 50% trosverminderingsbehandeling het ‘n beduidende positiewe verskil in die sensoriese analises gemaak, maar nie ‘n beduidende verskil in die chemiese analises van die wyne nie. Calitzdorp se terroir het ‘n soortgelyke effek op Touriga Naçional as dié van die DDR terroir en daarom kan Calitzdorp soortgelyke goeie tafel- en portwyne van Touriga Naçional produseer.

Thesis (MScAgric) -- University of Stellenbosch, 2001.
ENGLISH ABSTRACT: There is an increasing demand by the consumer for knowledge and understanding of the origin of each wine produced. This origin is directly linked to the interaction between the environment and grapevine, and therefore to the terroir. A terroir can be defined as a complex of natural factors being expressed through the final product and must therefore be studied in two steps, namely, the identification of relatively homogenous natural terroir units followed by their ecophysiological characterisation. The aim of this study was to characterise the Bottelaryberg-Simonsberg-Helderberg wine growing area according to existing digital information and to identify natural terroir units. The study area is situated to the southwest of Stellenbosch and covers an area of approximately 25 000 ha. Topography is a static feature of the landscape and affects the sunlight interception by a slope, exposure of a site to winds and drainage of soil water and air. It forms an important component of the terroir concept and has a strong interaction with the environmental components of climate and soil. The study area is bordered by mountains and bisected by a river valley resulting in a large variation in aspect and altitude affecting both spatial and temporal temperature variability. There is no doubt as to the important effect of climate on wine character and quality. A number of indices can be used to describe the regional climate. The study area has a Mediterranean climate with notable spatial variation of all climatic parameters due to its complex topography and proximity to the ocean. The effect of geology on wme character is less clear but appears to act through its contribution to the physical properties of the soil. In the Bottelaryberg-Simonsberg- Helderberg study area the geology is complex due to the high degree of tectonic movement and mixing of parent material. In situ weathering of rocks is seldom the only source of soil formation. Soil has a number of contributing factors affecting wine character and quality, inter alia, soil colour, temperature, chemical composition, depth and texture (affecting the water supplying properties of the soil). It is the last two that appear to have the most significant effect. Soil depth affects the buffer capacity of the soil to temper climatic extremes and the water supply has a well-recorded effect on vine growth and functioning. There is a high degree of soil variation in the Bottelaryberg-Simonsberg-Helderberg study area that is difficult to represent in soil associations. A pattern of soil distribution, however, can be noticed in relation to landscape variation. Terrain morphological units, altitude and aspect were used as pnmary keys for the identification of natural terroir units. Broad soil categories and geological information were included at a secondary level. This resulted in 195 units. These natural terroir units will form the basis for future ecophysiological characterisation in order to determine possible future cultivar distribution as well as the terroir effect on wine character.
AFRIKAANSE OPSOMMING: Daar is toenemende aanvraag vanaf die verbruiker vir kennis en begrip van die oorsprong van elke wyn wat geproduseer word. Die oorsprong is direk aan die interaksie tussen die omgewing en wingerd gekoppel, en daarom ook die terroir. Terroir kan omskryf word as die kompleks van natuurlike faktore wat in die finale produk uitdrukking vind en studies daarvan moet dus in twee stappe plaasvind, d.i. die identifisering van relatiewe homogene natuurlike terroir eenhede gevolg deur die ekofisiologiese karakterisering daarvan. Die doel van die studie was om die Bottelaryberg-Simonsberg-Helderberg wynproduserende gebied te karakteriseer, met behulp van bestaande versyferde data en om natuurlike terroir eenhede te identifiseer. Topografie is 'n vaste landskapskenmerk en beïnvloed sonligonderskepping deur hellings, blootstelling van 'n ligging aan wind en die dreinerin~ van grondwater en beweging van koue lug. Dit is 'n belangrike deel van die terroir konsep en het sterk interaksie met omgewingsfaktore van grond en klimaat. Die studiegebied word begrens deur berge en is deursny deur 'n riviervallei, met groot variasie in helling en aspek. Beide hiervan beïnvloed die ruimtelike- en daaglik-variasies in daaglikse maksimum temperatuur. Die belangrike effek van klimaat op wynkarakter en kwaliteit is duidelik soos weerspieël deur die beskikbaarheid van 'n aantal makroklimaatsindekse. Alle klimaatsparameters word deur topografie beïnvloed. Temperatuur en relatiewe humiditeit word ook deur afstand vanaf die see beïnvloed. Die studie area het 'n Meditereense klimaat, met merkwaardige ruimtelike variasie van alle klimaatsparameters. Die effek van geologie op wynkarakter is minder duidelik, maar het waarskynlik 'n effek op die fisiese eienskappe van 'n grond. Die geologie in die Bottelaryberg-Simonsberg- Helderberg studiegebied is kompleks, as gevolg van die hoë graad van tektoniese beweging en vermenging van moedermateriaal. In situ vorming van gronde uit gesteentes vind selde plaas: Grond het 'n groot aantal bydraende faktore, wat wynkarakter en -kwaliteit kon beïnvloed, onder andere, grondkleur, -temperatuur, -chemiese samestelling, -diepte en -tekstuur (wat die waterleweringsvermoë van die grond bepaal). Dit is veral laasgenoemde twee faktore wat blykbaar die mees opvallendste effek openbaar. Gronddiepte bepaal die buffer kapasiteit van die grond om klimaatsuiterstes te kan weerstaan en die waterleweringsvermoë het 'n alombekende effek op wingerdgroei en funksionering. Daar is 'n hoë graad van grondvariasie in die Bottelaryberg-Simonsberg-Helderberg studiegebied wat moeilik is om met grondassosiasies weer te gee. Daar is wel 'n patroon van grond distribusie wat verband hou met landskapvariasie. Terrein morfologiese eenhede, hoogte en aspek is gebruik as primêre sleutels vir die indentifisering van natuurlike terroir eenhede. Globale grondkategorieë en geologiese inligting is op 'n sekondêre vlak gebruik. Dit het 195 eenhede tot gevolg. Die natuurlike terroir eenhede sal die basis vorm vir toekomstige ekofisiologiese karakterisering, om die terroir effek op wynkarakter te kan bepaal.

Thesis (PhD(Agric))--Stellenbosch University, 2012.
ENGLISH ABSTRACT: A lack of defects is required for successful table grape marketing, which pre-suppose optimal vine performance, berry development and post-harvest quality. The supply of mineral nutrients affects vine development, physiology and berry quality. Despite a vast amount of research conducted over decades, there remain many unresolved issues regarding table grape vine nutrition to ensure optimal table grape quality and shelve-life. Unjustified fertilisation practices often include excessive applications of nitrogen (N), potassium (K) and calcium (Ca). A four-year field trial was therefore conducted on a sandy soil in the Paarl district of South Africa, using grafted on Ramsey, and trained to a gable trellis system. Nitrogen, potassium and calcium were applied, singular or in combination, at rates up to 300% the calculated annual nutritional requirement. The effect of these excessive applications on table grape performance under typical South African cultivation conditions was investigated for Vitis vinifera L. cv. Prime Seedless, a very early seedless table cultivar that is produced with minimum berry diameter of 18mm, with special reference to 1) vegetative growth, 2) expression of grapevine nutrient availability through foliar analyses, 3) berry nutrient accumulation patterns of this early cultivar, 4) manipulation of berry nutrient content through soil and bunch directed applications and 5) the effect of berry nutrient content on its quality. No definite vegetative growth responses (expressed as shoot length, leaf surface area and shoot mass) and leaf chlorophyll content differences were obtained for all the treatments. These results were obtained in a vineyard on a sandy soil where excessive N fertilisation caused a reduction of soil pH to detrimentally low levels and where the excessive N, K and Ca applications reduced mutual concentrations and that of Mg, in the soil. A lack of stimulation in vegetative growth may therefore be ascribed to the combined negative effect of these excessive applications on soil pH and vine nutrition. Although the N content of petioles was higher for treatments where N was applied, consistent significant increases in petiole N with N fertilisation were not observed. Petiole N concentration showed a decreasing trend throughout the season. Petiole K concentrations were significantly increased by the K fertilisation at all phenological stages. None of the K fertilisation treatments, however, succeeded to raise petiole K concentrations above the accepted maximum norms and petiole K concentration at a specific sampling stage varied significantly between the four seasons. A general decrease in petiole K concentration was found for all seasons. Calcium fertilisation did not increase soil Ca content, resulting in a lack of differences in petiole Ca concentrations between treatments. An increase in petiole Ca concentration towards harvest was obtained. Correlations between petiole nutrient concentration and berry mineral content at harvest were poor. The only way of knowing the mineral content of berries would seem to be by measuring it directly instead of deducing it from the results of leaf or petiole analyses. The dynamics of berry growth impacted on berry nutrient concentration. Early rapid berry growth, predominantly due to cell division and cell growth, was associated with the most rapid decreases in N, P and Ca concentration. Due to mobility of K and Mg in the plant, that exceeds other nutrients, the decrease in concentration of these two mineral elements was not as pronounced as that of the others. Nutrient accumulation was most rapid during the pre-véraison period, but only Ca showed a definite termination during the early ripening period. The continued inflow of N, P, K and Mg, albeit at slower rates immediately after véraison, should be taken into consideration when fertilisation is applied. As a table grape, total accumulation of each nutrient in Prime Seedless berries also far exceeded that of other cultivars studied thus far. A particular difference is that the berry flesh:skin ratio is much higher than that of previously studied cultivars, leading to higher levels of nutrient accumulation in the flesh. Slightly larger berry size was obtained for N applications and is ascribed to slight increases in early vegetative growth, allowing a better response to GA3 treatments. The use of GA3 for berry enlargement is also considered the reason why K fertilisation, resulting in increased berry K levels, did not affect berry size, as is often found for wine grapes. Higher available NO3 - in the soil on account of excessive N applications resulted in higher levels of berry N, despite sub-optimal soil pH regimes that were created by these treatments. Berry K concentration and content were increased by K fertilisation. Rapid vine K uptake and translocation to the berries seem to negate the reduced vine nutritional status as observed in petioles for situations of over-fertilisation with N. Berry Ca levels were not increased by Ca fertilisation or by bunch applied Ca. The rapid rates of berry growth, together with low rates of berry Ca uptake and Ca uptake that terminates at the onset of ripening, are assumed to be the main reasons for this result. Low levels of decay as well as a lack of consistently increased decay were obtained for N containing treatments. Nitrogen levels in the berries above which their susceptibility to fungal infection is increased, should be established. Information on specific N compounds that may lead to more susceptibility is required. Potentially increased berry browning on account of high rates of K fertilisation needs to be further investigated; indications that this may occur were observed. Neither soil applied Ca nor bunch applied Ca improved berry quality, although Ca treatments seemed to reduce decay during the only season that significant differences were obtained. The negative effect of excessive fertilisation on soil chemistry of sandy soils has again been highlighted by this study. This annuls the fertilisation, leading to inefficient fertilisation and a lack of the desired responses. As indicator of vine nutrient availability, petiole analysis, was proven unreliable and should be evaluated in parallel with soil analyses, taking seasonal variation into consideration. The danger of being only guided by published norms for leaf nutrient concentrations when establishing fertilisation practices has again been highlighted by this study. This research indicated that for a very early cultivar like Prime Seedless, nutrient accumulation dynamics can already start to change during the pre-véraison period in some seasons. This is due to different edaphic and climatic conditions as well as berry size, which leads to much higher flesh:skin ratios. Future research on table grapes would need to develop an understanding of the various factors and dynamics that determine berry nutrient concentration and accumulation of early ripening, large berry sized, seedless table grape cultivars.
AFRIKAANSE OPSOMMING: Suksesvolle bemarking van tafeldruiwe is ten nouste afhanklik van die beskikbaarheid van druiwe sonder defekte, wat ‘n direkte verband met optimale wingerdprestasie, korrelontwikkeling en na-oes kwaliteit inhou. Voorsiening van minerale voedingstowwe beïnvloed die stok se groei, fisiologie en korrelgehalte. Ten spyte van ‘n oorweldigende hoeveelheid navorsing wat oor dekades reeds gedoen is, is daar steeds onopgeloste kwessies aangaande bemesting van tafeldruiwe vir optimale druifgehalte en houvermoë. Die gevolg is onoordeelkundige bemestingspraktyke wat o.a. aanleiding gee tot oorbemesting met stikstof (N), kalium (K) en kalsium (Ca). ‘n Vier-jaar-lange veldproef is gevolglik op ‘n sandgrond in die Paarl distrik (Suid-Afrika) onderneem deur gebruik te maak van Vitis vinifera L. cv. Prime Seedless geënt op Ramsey en op ‘n dubbel-gewel prieelstelsel opgelei is. Stikstof, K en Ca is alleen, of in kombinasie, toegedien teen hoeveelhede gelykstaande aan 300% van die wingerd se jaarlikse behoefte. Die effek van hierdie oormatige toedienings op tafeldruif prestasie onder Suid-Afrikaanse verbouingstoestande is ondersoek, met spesiale verwysing na 1) vegetatiewe groei, 2) uitdrukking van voedingstofbeskikbaarheid deur blaarontledings, 3) die voedingstof akkumulasie patrone van korrels van hierdie vroeë kultivar, 4) manipulasie van korrel voedingstofinhoud deur grond en trosgerigte toedienings en 5) die effek van korrel voedingstofinhoud op kwaliteit. Die doel van die proef was om bemestinspraktyke van Prime Seedless, ‘n baie vroeë pitlose tafeldruifkultivar met ‘n minimum korrelgrootte van 18 mm, te verfyn. Deur die akkumulasie patrone van die druiwe uit te klaar is daar ook ondersoek ingestel of oestyd en na-oes gehalte deur oormatige toediening van voedingstowwe affekteer word. Geen duidelike verskille betreffende vegetatiewe groeireaksies (uitgedruk as lootlengte, blaaroppervlaktes en lootmassas) asook verskille in blaar chlorofilinhoud is vir die behandelings verkry nie. Hierdie resultate is verkry in ‘n wingerd op ‘n sandgrond, waar oormatige N-bemesting aanleiding gegee het tot grond pH verlagings tot die peil van nadelige vlakke. Verder het die oormatige N, K en Ca toedienings wederkerige verlagings in konsentrasies, asook op dié van Mg, in die grond teweeggebring. Die tekort aan vegetatiewe groeiresponse op die behandelings kon dus toegeskryf word aan ‘n gekombineerde effek van die oormatige toedienings op grond pH en voedingstofbalanse. Hoewel die N-inhoud van bladstele hoër was vir behandelings wat N toediening ingesluit het, was daar nie konstante toenames in die vlakke verkry nie. Bladskyf N-konsentrasie het afgeneem deur die loop van die groeiseisoen. Vir alle fenologiese stadiums was bladskyf Kkonsentrasies betekenisvol verhoog deur K-bemesting. Nie een van die Kbemestingsbehandelings het egter daarin geslaag om bladskyf K inhoud vir enige monstertyd bo die algemeen aanvaarde maksimum norms te lig nie. Verder het bladskyf K inhoud by ‘n spesifieke fenologiese stadium ook betekenisvol tussen seisoene verskil. Die K-inhoud van bladskywe het afgeneem met verloop van die seisoen. Kalsiumbemesting het nie die grond se Ca inhoud deurgans verhoog nie, wat dus die tekort aan verskille in Ca konsentrasies tussen die behandelings verklaar. ‘n Toename in Ca konsentrasie en korrel Ca inhoud is vanaf set tot oes waargeneem. Swak korrelasies tussen bladskywe se voedingstofinhoude en korrels se voedingstofinhoude is verkry. Die enigste manier waarop korrels se voedingstofinhoude dus afgelei kan word, blyk te wees deur direkte bepaling daarvan. Voedingstofinhoude van korrels is deur groeipatrone daarvan beïnvloed. Vroeë korrelgroei, hoofsaaklik a.g.v. seldeling en selgroei, het met die vinnigste afnametempo van N, P en Ca gepaard gegaan. As gevolg van die hoër beweeglikheid van K en Mg in die plant in vergelyking met ander voedingstowwe, was die afname in konsentrasie van hierdie twee elemente nie so groot soos vir die ander nie. Voedingstofakkumulasie was die vinnigste in die periode voor deurslaan. Slegs Ca het ‘n beeïndiging van opname aan die einde van hierdie periode getoon. Die voortgesette opname van N, P, K en Mg, alhoewel stadiger kort na deurslaan, moet in ag geneem word wanneer bemesting toegedien word. Vir hierdie kultivar het die totale opname van elke bemestingstof dié van die ander kultivars wat tot hede bestudeer is, ver oorskry. ‘n Spesifieke verskil is ‘n baie hoër vleis:dop verhouding as wat vir ander kultivars verkry is. Dit gee aanleiding tot baie hoër vlakke van voedingstofakkumulasie in die vleis. Effens groter korrelgroottes is verkry waar N toedienings gemaak is. Dit word toegeskryf aan klein toenames in vroeë vegetatiewe groei, wat dus beter reaksie op GA3 behandelings tot gevolg gehad het. Die gebruik van GA3 vir korrelvergroting word ook beskou as die rede waarom K-bemesting, wat tot hoër vlakke van K in die korrels aanleiding gegee het, nie korrelgrootte, soos by wyndruiwe, bevorder het nie. Hoër NO3 - in die grond (water), na aanleiding van N toedienings, het aanleiding gegee tot hoer vlakke van N in die korrels. Dit het plaasgevind ten spyte van sub-optimale grond pH wat deur die oormatige N toedienings veroorsaak is. Korrel K konsentrasie en -inhoud is deur K-bemesting verhoog. Vinnige opname en translokasie van K na die korrels het ook geblyk die rede te wees waarom die verlaagde voedingstatus van die stokke a.g.v. oorbemesting met N nie die korrels se K inhoud geaffekteer het nie. Die vinnige groeitempo van die korrels, tesame met lae vlakke van Ca opname, asook korrels se Ca opname wat tydens rypwording ophou, word as die redes vir die tekorte aan behandelingseffekte beskou. Lae vlakke van bederf, asook ‘n tekort aan betroubare tendense dat bederf deur Nbemesting verhoog word, is verkry. Daar moet vasgestel word of daar N vlakke in die korrels is waarbo hul vatbaarheid vir swaminfeksies verhoog word, en of daar spesifieke N verbindings is wat die korrels meer vatbaar maak vir bederf. Indikasies dat K-bemesting interne verbruiningsvlakke verhoog het, regverdig verdere ondersoek. Korrelkwaliteit is nie deur grond- of trosgerigte toedienings bevoordeel nie. Die negatiewe effek van oormatige bemesting op die chemiese samestelling van sandgronde is weer deur hierdie navorsing uitgelig. Dit lei tot oneffektiewe bemesting en ‘n tekort aan die verlangde effekte. Blaarontledings blyk onbetroubaar te wees as aanduiding van voedingstof beskikbaarheid. Dit moet evalueer word saam met grondontledings en ook seisoenale variasie in ag neem. Die gevaar om slegs deur gepubliseerde norme gelei te word wanneer bemestingspraktyke bepaal word, is weer deur hierdie navorsing uitgelig. Voorst is daar in hierdie navorsing gevind dat voedingstof akkumulasiepatrone van ‘n baie vroeë kultivar soos Prime Seedless alreeds voor deurslaan begin verander a.g.v. omgewingstoestande en korrelgroei wat tot ‘n veel hoër vleis:dop verhouding aanleiding gee. Toekomstige navorsing op tafeldruiwe behoort die faktore en dinamika wat voedingstofkonsentrasie en -akkumulasie in korrels van vroeë, groot korrel, pitlose tafeldruifkultivars beïnvloed verder te ondersoek.

Thesis (MScAgric)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: Due to the extraordinary drought resistance of the grapevine, viticulture without irrigation in the winter rainfall coastal areas of South Africa is a feasible and commonly used practice. Wine quality is largely determined by the quality of the grapes from which it is made. Grapevine physiology is affected both directly and indirectly by water stress, which may vary according to soil type and prevailing atmospheric conditions. The water status of the grapevine can affect grape composition profoundly, either directly or indirectly, in either a positive or negative way, depending on the degree as well as the duration of water stress. There are three important factors involved in the development of water stress, namely the transpiration rate, the rate of water movement from the soil to the roots, and the relationship of soil water potential to leaf water potential. All three these factors are affected by atmospheric and/or soil conditions. In warm winelands such as South Africa (Western Cape), with a mediterranean climate which is characterised by a hot, dry summer period, the most important characteristic of soil is its ability to supply sufficient water to the grapevine during the entire growing season. Leaf water potential (Ψl) has gained wide acceptance as a fundamental measure of grapevine water status, and has been widely applied in viticultural research. Shortly before dawn, Ψl approaches equilibrium with soil water potential and reaches a maximum daily value. The study formed an integral part of a comprehensive, multi-disciplinary research project (ARC Infruitec-Nietvoorbij Project No. WW13/01) on the effect of soil and climate on wine quality, which commenced in 1993 and will be completed in 2004. This study was conducted during the 2002/03 growing season in two Sauvignon blanc vineyards situated at Helshoogte and Papegaaiberg, both in the Stellenbosch district, approximately nine kilometres apart. Two experiment plots, representing contrasting soil types in terms of soil water regime, were selected in each vineyard. At Helshoogte the two soils represented the Tukulu and Hutton forms, and the soils at Papegaaiberg were of the Avalon and Tukulu forms. The aim of this study was to determine the effect of atmospheric conditions and soil water status on the level of water stress in the grapevines for each soil at each locality, as well as the effect of grapevine water stress on yield and wine quality. This was done by determining and comparing the soil water status, soil water holding capacity of the soils and the evapotranspiration of the grapevines on the two different soils, at each of the two localities differing in mesoclimate and topography. The atmospheric conditions at the two localities during the 2002/03 season were also determined and compared to the long-term average atmospheric conditions, and the level of water stress of grapevines on each soil at each locality was measured. During the 2002/03 growing season, atmospheric conditions were relatively warm and dry in comparison to the long-term averages of previous seasons. These conditions accentuated the effects of certain soil properties that may not come forward during wetter, normal seasons. The usually wet Tukulu soil at Helshoogte was drier than expected during the 2002/03 season compared to the Hutton soil. Due to more vigorous growth on the Tukulu soil, grapevines extracted more soil water early in the season, leading to a low soil water matric potential and more water stress in the grapevines. Due to the higher vigour, resulting in more canopy shading, and more water stress, the dominant aroma in wines from the Tukulu soil was fresh vegetative. The Hutton soil maintained consistency with regards to both yield and wine quality compared to previous seasons. On the other hand the Tukulu soil supported a higher yield, but with lower than normal wine quality. The Avalon soil at Papegaaiberg maintained the highest soil water potential towards the end of the season, probably due to capillary supplementation from the sub-soil. Grapevines on the Tukulu soil at Papegaaiberg experienced much higher water stress than ones on the other three soils, especially during the later part of the season. This could be ascribed to a combination of factors, the most important being the severe soil compaction at a shallow depth, seriously limiting rooting depth and root distribution, which is detrimental to grapevine performance. Both the soil water status and atmospheric conditions played important roles in determining the amount of water stress that the grapevines experienced at different stages. The air temperature and vapour pressure deficit throughout the season were consistently lower at Helshoogte, the cooler terroir, compared to Papegaaiberg, the warmer terroir. At flowering, Ψl was lower for grapevines at Helshoogte than at Papegaaiberg, showing that diurnal grapevine water status was primarily controlled by soil water content. The difference in grapevine water status between the two terroirs gradually diminished until it was reversed during the post harvest period when Ψl in grapevines at Papegaaiberg tended to be lower compared to those at Helshoogte. The relatively low pre-dawn Ψl at Helshoogte indicated that the grapevines were subjected to excessive water stress resulting from the low soil water content. However, grapevines at Helshoogte did not suffer material water stress (i.e. Ψl < -1.20 MPa) during the warmest part of the day, suggesting that partial stomatal closure prevented the development of excessive water stress in the grapevines. This suggests that low pre-dawn Ψl values do not necessarily imply that grapevines will experience more water stress over the warmer part of the day, or visa versa. This does not rule out the possibility that side-effects of partial stomatal closure, such as reduced photosynthesis, can have negative effects on grapevine functioning in general. These results also suggest that measurement of diurnal Ψl cycles at various phenological stages is required to understand and quantify terroir effects on grapevine water status.
AFRIKAANSE OPSOMMING: Danksy die droogteweerstand van die wingerdstok is die verbouing van wingerde sonder besproeiing ‘n praktiese en algemene verskynsel in die winterreënval-areas van Suid-Afrika. Wynkwaliteit word grootliks bepaal deur die kwaliteit van die druiwe waarvan dit gemaak word. Wingerdfisiologie word direk en indirek beïnvloed deur waterstres, wat kan varieer volgens die grondtipe en die heersende atmosferiese toestande. Die waterstatus van die wingerdstok beïnvloed druifsamestelling, direk of indirek, en positief of negatief, afhangend van die graad en tydsduur van die waterstres. Daar is drie belangrike faktore betrokke by die ontwikkeling van waterstres, naamlik die transpirasietempo, die tempo van waterbeweging vanaf die grond na die wortels, en die verhouding tussen die grondwatermatrikspotensiaal tot blaarwaterpotensiaal. Al drie die faktore word beïnvloed deur die atmosferiese en/of grondtoestande. In warm wynboulande soos Suid-Afrika (Weskaap), met ‘n meditereense klimaat wat gekarakteriseer word deur ‘n warm, droë somerperiode, is die belangrikste eienskap van grond die vermoë om voldoende water aan die wingerdstok te verskaf gedurende die hele seisoen. Blaarwaterpotensiaal (Ψl) het wye aanvaarding bekom as die fundamentele meting van wingerstokwaterstatus, en word wyd toegepas in wingerdkundige navorsing. Kort voor sonsopkoms, nader Ψl ‘n ewewig met die grondwatermatrikspotensiaal en bereik ‘n maksimum daaglikse waarde. Die studie vorm ‘n integrale deel van ‘n omvattende, multi-dissiplinêre navorsingsprojek (ARC Infruitec-Nietvoorbij Projek No. WW13/01) op die effek van grond en klimaat op wynkwaliteit, wat in 1993 in aanvang geneem het en in 2004 afgehandel sal word. Hierdie studie is uitgevoer gedurende die 2002/03 seisoen in twee Sauvignon blanc wingerde geleë by Helshoogte en Papegaaiberg, beide in die Stellenbosch distrik, ongeveer nege kilometer van mekaar. Twee eksperimentele persele, elkeen verteenwoordigend van kontrasterende grondtipes in terme van grondwaterregime, is geselekteer in elke wingerd. By Helshoogte word die twee gronde verteenwoordig deur die Tukulu en Hutton grondvorms, en die gronde by Papegaaiberg is van die Avalon en Tukulu vorms. Die doel van die studie was om die effek van atmosferiese toestande en grondwaterstatus op die wingerdstok se waterstatus vir elke grond by die twee lokaliteite te bepaal, sowel as die effek van die wingerdstok se waterstatus op die opbrengs en wynkwaliteit. Dit is gedoen deur die grondwaterstatus, die grondwaterhouvermoë, sowel as die evapotranspirasie van die wingerdstokke op die twee verskillende gronde by elk van die twee lokaliteite, wat verskil in mesoklimaat en topografie, te bepaal en vergelyk. Die atmosferiese toestande by die twee lokaliteite gedurende die 2002/03 seisoen is ook bepaal en vergelyk met die langtermyn gemiddelde atmosferiese toestande. Die vlakke van waterstres in wingerdstokke op elke grond by elke lokaliteit is ook gemeet. Gedurende die 2002/03 groeiseisoen, was die atmosferiese toestande relatief warm en droog in vergelyking met die langtermyn gemiddeldes van vorige seisoene. Hierdie kondisies aksentueer die effek van sekere grondeienskappe wat nie noodwendig na vore kom gedurende normale, natter seisoene nie. Die gewoonlike nat Tukulu grond by Helshoogte was droër as verwag gedurende 2002/03 in vergelyking met die Hutton grond. As gevolg van sterker groekrag op die Tukulu grond, het wingerdstokke meer grondwater onttrek vroeg in die seisoen, wat gelei het tot ‘n lae grondwatermatrikspotensiaal en meer waterstres in die wingerdstokke. Die sterker groeikrag het meer beskaduwing van die lower asook meer waterstres veroorsaak, wat gelei het daartoe dat die dominante aroma in wyne vanaf druiwe op die Tukulu grond vars vegetatief was. Die Hutton grond het bestendig gebly in terme van opbrengs en wynkwaliteit in vergelyking met vorige seisoene. Daarteenoor het die Tukulu grond ‘n hoër opbrengs gelewer, maar met laer as gewoonlike wynkwaliteit. Die Avalon grond by Papegaaiberg het die hoogste grondwatermatrikspotensiaal behou tot die einde van die seisoen, heelwaarskynlik a.g.v. kapillêre aanvulling vanuit die ondergrond. Wingerdstokke op die Tukulu grond by Papegaaiberg het heelwat meer waterstres ondervind as op die ander drie gronde, veral later in die seisoen. Dit kan toegeskryf word aan ‘n kombinasie van faktore, die belangrikse daarvan die erge grondkompaksie vlak in die grond, wat worteldiepte en -verspreiding ernstig beperk het, wat op sy beurt nadelig is vir wingerdprestasie. Beide die grondwaterstatus en atmosferiese toestande het ‘n belangrike rol gespeel in die bepaling van die hoeveelheid waterstres wat die wingerdstok op verskillende stadiums ondervind het. Die lugtemperatuur en waterdampdruktekort was regdeur die seisoen laer by Helshoogte, die koeler terroir, as by Papegaaiberg, die warmer terroir. Gedurende blom was die Ψl laer vir wingerdstokke by Helshoogte as by Papegaaiberg, wat daarop wys dat daaglikse wingerdstok waterstatus hoofsaaklik deur die grondwaterinhoud bepaal was. Die verskil in wingerdstok waterstatus tussen die twee terroirs het geleidelik verminder totdat dit omgekeer was gedurende die na-oes periode toe Ψl in wingerdstokke by Papegaaiberg geneig het om laer te wees in vergelyking met die by Helshoogte. Die relatiewe lae voorsonop Ψl by Helshoogte het daarop gedui dat die wingerdstokke aan oormatige waterstres onderwerp was. Die wingerdstokke by Helshoogte het egter nie materiële waterstres (i.e. Ψl < -1.20 MPa) gedurende die warmste gedeelte van die dag ondervind nie, wat aandui dat gedeeltelike huidmondjiesluiting plaasgevind het om die ontwikkeling van oormatige waterstres te verhoed.Dit dui aan dat lae voorsonop Ψl waardes nie noodwendig impliseer dat wingerdstokke meer waterstres gedurende die warmste gedeelte van die dag sal ondervind nie, of visa versa. Dit sluit nie die moontlikheid uit dat negatiewe neweeffekte van gedeeltelike huidmondjiesluiting, soos ‘n vermindering in fotosintese, ‘n negatiewe effek kan hê op die wingerdstok se funksionering in die algemeen nie. Hierdie resultate stel voor dat die meting van daaglikse Ψl siklusse gedurende verskeie fenologiese stadia benodig word om die effek van terroir op die wingerdstok se waterstatus te verstaan en te kwantifiseer.

Thesis (MscAgric (Viticulture and Oenology))--Stellenbosch University, 2008.
The effect of various irrigation strategies on grapevine water relations during the berry ripening period was investigated in a Shiraz/Richter 99 vineyard. Comparisons between different irrigation strategies (full/seasonal, véraison+post véraison, post véraison and no irrigation) were made. During the day, the seasonally irrigated vines experienced less water stress than the deficit treatments. Non-irrigated vines seemed to maintain higher diurnal leaf water potentials. Lower leaf water potentials indicated lower water contents in the vegetative and reproductive tissue. Full irrigation seemed to stimulate primary shoot length. Longer water deficit induced earlier and more complete shoot maturation (reserve accumulation). Re-distribution of leaf area on the shoot may occur when vines are subjected to water deficit. Extended water deficit seemed to induce earlier and restricted water loss from vegetative tissue. The water relations were reflected in the berry size. Irrigation during ripening seemed to induce a continuation of berry water loss. Transpiration losses were apparently much higher in fully irrigated vines whereas stomatal control efficiently maintained water relations in non-irrigated vines. Water deficit seemed to have enhanced the soluble solid accumulation. Irrigation treatments did not seem to affect the titratable acid and pH. The post véraison irrigation in particular seemed to favour a wide window for harvesting. Irrigation at post véraison and especially véraison+post veraison seemed to have a greater effect on the synthesis and extraction of phenolics, anthocyanins and tannins in the berry skins. Different irrigation strategies may affect grapes in such a way that different wine styles are obtained.

Thesis (MScAgric (Viticulture and Oenology)--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: ‘Crimson Seedless’ is currently one of the most important and popular table grape cultivars produced in South Africa, and as such it is of great economic value for table grape producers. Major concerns with ‘Crimson Seedless’ is that it is prone to inadequate colouring, and with increased yields the berry size decreases. An additional difficulty is that methods used to increase berry size, further impede berry colouring. A plant growth regulator (PGR) commonly used in table grape production, to enhance colour formation, is ethephon (2-chloro-ethyl-phosphonic acid, 2-CEPA). In recent years significant research has been done on the effect of sunlight on anthocyanin production in grapes, although this has primarily been on wine grape cultivars. Currently, there is limited knowledge on the effect of sunlight on table grapes, and how this might influence their anthocyanin composition and content. The effect of ethephon on colour of grapes and other fruit have been extensively researched and well documented. However, the effect of ethephon on the anthocyanin composition of ‘Crimson Seedless’ is not well known. The current study aimed to explore the effect of sunlight (by matter of exclusion) and management practices, namely defoliation and ethephon application, on the anthocyanin profile and content of ‘Crimson Seedless’. Four different treatments were applied to two ‘Crimson Seedless’ vineyards, the first site located in Paarl, and the second in De Doorns. The treatments were: 1. Naturally exposed bunches, 2. Exposed bunches treated with ethephon, 3. Bunches kept in shade boxes, 4. Shaded bunches treated with ethephon. At the De Doorns site an additional defoliation treatment was superimposed over the above treatments. An HPLC technique was modified for the separation and detailed profiling of ‘Crimson Seedless’ anthocyanins and was used to analyse the effect of the reported treatments on the anthocyanin profile of berry skins. The predominant anthocyanin in ‘Crimson Seedless’ is peonidin-3-glucoside (Pn-gluc), and this was found to be significantly increased only by ethephon application, and was not altered by sunlight or leaf removal. The responses of the other anthocyanin types varied according to the respective treatments applied. However, a general observation was that ethephon application more consistently increased the concentration of anthocyanins in berry skins than did sunlight. Leaf removal had the least significant effect on anthocyanin concentration.
AFRIKAANSE OPSOMMIMG: ‘Crimson Seedless’ is tans een van die belangrikste en gewildste tafeldruif cultivars wat in Suid-Afrika verbou word en daarom is dit van groot ekonomiese waarde vir tafeldruifprodusente. ‘Crimson Seedless’ is egter daarvoor bekend dat dit te swak kleur (volgens uitvoer spesifikasies) en tweedens is die cultivar geneig om kleiner korrels te ontwikkel wanneer die oeslading vermeerder word. ‘n Addisionele probleem is dat die praktyke wat in die industrie gebruik word om korrels te vergroot ‘n verdere negatiewe impak op ‘Crimson Seedless’ se kleur ontwikkeling kan veroorsaak. Die plant-groei-reguleerder wat algemeen in tafeldruif verbouing gebruik word, ten einde beter gekleurde druiwe te produseer, is ethephon (2-chloro-ethyl-phosphonic acid, 2-CEPA). In die laaste paar jaar was daar baie navorsing gedoen oor die effek wat sonlig het op die antosianien produksie van druiwe, maar navorsing was gefokus op wyndruif cultivars. Huidiglik is daar beperkte tegniese kennis oor die effek wat sonlig op tafeldruiwe het, en hoe dit moontlik die antosianien samestelling en inhoud kan beïnvloed. Daar is ook reeds verskeie studies gedoen en data gepubliseer oor die invloed wat ethephon op die kleur het van druiwe en ander vrugte, maar die invloed wat ethephon op die antosianien samestelling van ‘Crimson Seedless’ het, is nie wel bekend nie. Die doel van hierdie studie was om die effek van sonlig (deur uitsluiting) en bestuurspraktyke (blaarverwydering en ethephon toediening) te bestudeer en hoe dit die antosianien samestelling van ‘Crimson Seedless’ beïnvloed. Vier verskillende behandelings is toegedien in twee ‘Crimson Seedless’ wingerde, die eerste proefperseel in die Paarl en die tweede proefperseel in De Doorns. Die behandelings was: 1. Natuurlik blootgestelde trosse, 2. blootgestelde trosse met ethephon, 3. Trosse met skadubokse omhul, 4. Skaduboks trosse met ethephon. By De Doorns is ‘n addisionele blaarverwydering proef bygebring. ‘n HPLC tegniek was aangepas om die antosianien samestelling en inhoud van ‘Crimson Seedless’ te bepaal, en om die effek van die behandelings te ondersoek. Die HPLC data het getoon dat peonodien-3-glukosied (Pn-gluc) die primêre antosianien in ‘Crimson Seedless’ is met die hoogste inhoud van al die antosianiene. Pn-gluc was betekenisvol beïnvloed deur ethephon toediening, terwyl die ander behandelings geen betekenisvolle effekte daarop gehad het nie. Die effekte wat die ander antosianiene gehad het, het gevarieer volgens die behandelings wat toegedien was. ‘n Algemene observasie was dat ethephon toediening die antosianien konsentrasie in ‘Crimson Seedless’ druiwe skille meer konsekwent vermeerder het as die sonlig blootstelling. Die blaarverwydering het die minste betekenisvolle effek op die antosianien inhoud van ‘Crimson Seedless’ gehad.

In order to prepare our students for a challenging workplace, the Department of Viticulture and Oenology at Stellenbosch University in South Africa have ‘layered’ Engaged Learning strategies throughout the four-year undergraduate degree in an approach that is innovative in a science-based programme. In this research project, we assessed the effects of service-learning (SL) and a six-month internship on student employability by analysing reflections that were collected over a number of years. We also asked industry members whether they felt students had improved in key areas after the final year internship. The student submissions for SL showed evidence of personal growth and transformation, and those for the internship reflected industry requirements for professional skills in a complex and technically demanding milieu. It was found that these engaged experiences provided sound preparation for working life, as well as giving students opportunities for self-questioning and personal growth, which is unusual in the natural sciences learning environment.