No description available.

Thesis (MSc)--Stellenbosch University, 1955. / ENGLISH ABSTRACT: no abstract available / AFRIKAANSE OPSOMMING: geen opsomming

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Mucoralean fungi are mostly saprotrophs that are frequently encountered in soil habitats. Using an isolation temperature of circa 25°C, other workers obtained these fungi from a wide diversity of geographical areas in southern Africa. However, it is known that psychrotolerant mucoralean fungi, able to grow at 25°C as well as at 5°C, occur in pristine Alti Mountain Grassland. Nothing is known about the diversity of these psychrotolerant soil fungi in other vegetation types of South Africa. Consequently, in this study, the psychrotolerant fungal taxa and numbers in soil from a vineyard and from pristine Mountain Fynbos were determined using an incubation temperature of 4°C and a complex isolation medium. The latter contained agar, malt extract, peptone, yeast extract, penicillin and streptomycin sulphate. Soil samples were analysed in late summer, autumn and mid-winter. It was found that, for the samples taken in late summer and autumn, the diversity of mucoralean species in the soil differed between fynbos and vineyard. In winter however, no significant difference was detected between the Shannon's diversity indices of mucoralean species in the soil samples taken from the two habitats. It was found that in both soil types, the percentage mucoralean fungi on the plates increased from summer to winter. In addition, the numbers of detectable Morlierella subgenus Morlierella on the plates were higher in winter than in late summer. The diversity of mucoralean species obtained during winter in fynbos and vineyard soil was significantly less than the diversity of these species in Alti Mountain Grassland soil. To determine if the Morlierella subgenus Morlierella isolates from the fynbos and vineyard soil, and those obtained from Alti Mountain Grassland, differ in the ability to grow at low temperatures, the radial growth rate on malt extract agar at 4°C and BOC was determined for each isolate. The results indicate that not only did seasonal changes occur in the taxa within Morlierella subgenus Morlierella, but that the isolates dominating the soil in different seasons also differed in the ability to grow at low temperatures. The percentage of isolates that had reached greater colony diameters after B days of incubation at 4°C, was higher for the isolates obtained in the cold wet month of July than for those obtained in the warmer dryer month of February. Similar results were obtained with the radial growth experiments conducted at BOC. The Morlierella subgenus Morlierella isolates obtained in winter from fynbos and vineyard soil showed less variation in low temperature growth rate than the isolates of this taxon obtained in winter from Alti Mountain Grassland soil during a previous study. This variation corresponds to the greater number (20) of Morlierella subgenus Morlierella species found in the grassland soil. Altogether only seven species of this subgenus was detected during the present study in the fynbos and vineyard soil samples. It was speculated that this difference in diversity between the fynbos and vineyard isolates, and the grassland isolates obtained in a previous study, might have been as a result of differences in the habitat or the enumeration methods used. The phylogenetic relationship between different psychrotolerant isolates of Morlierella subgenus Morlierella originating from the soil of the fynbos, vineyard and Alti Mountain Grassland, was subsequently determine through comparison of ITS regions, within ribosomal RNA repeats. Consequently, 45 psychrotolerant Morlierella subgenus Morlierella isolates originating from the three soil habitats was compared on the basis ITS 1 nucleotide sequence composition and radial growth rate at 4°C. Phylogenetic analyses showed that the isolates could be grouped into two clusters correlating with the ability to grow at low temperatures. Each cluster was further subdivided into two subgroups. It was found that except for one subgroup and the reference strain occurring in another subgroup, all the subgroups contain isolates originating from a single soil habitat. Therefore, the ITS 1 sequence of these fungi seems to indicate the original habitat and ability to grow at low temperatures. This correlation of the ITS sequence with the ecological habitat of a fungus has also been observed by other workers for other fungal groups. / AFRIKAANSE OPSOMMING: Mucoraliese fungi is meestal saprotrofe wat dikwels in grondhabitatte aangetref word. Deur gebruik te maak van 'n isolasietemperatuur van circa 25°C, het ander werkers dié fungi van 'n wye verskeidenheid geografiese gebiede in suidelike Afrika verkry. Dit is egter bekend dat die psigrotolerante mucoraliese fungi, wat in staat is om by 2SoC en ook by SaC te groei, in ongeskonde Alti Berg-Grasland voorkom. Niks is egter bekend oor die diversiteit van dié psigrotolerante grondfungi in ander veldtipes van suidelike Afrika nie. Die psigrotolerante fungustaksa en -getalle in grond van 'n wingerd en van ongeskonde Berg Fynbos is gevolglik in dié studie bepaal deur gebruik te maak van 'n inkubasietemperatuur van 4"C en 'n komplekse isolasiemedium. Laasgenoemde het agar, moutekstrak, peptoon, gisekstrak, penisillien en streptomisiensulfaat bevat. Grondmonsters is in die laatsomer, herfs en midwinter geanaliseer. Daar is 'n verskil gevind tussen die diversiteit van die mucoraliese spesies in die grond van fynbos en dié van wingerd in die monsters wat in die laatsomer en midwinter geneem is. In die winter is daar egter geen beduidende verskil gevind tussen die Shannon diversiteitsindekse van mucoraliese spesies in die grondmonsters wat uit die twee habitatte getrek is nie. In albei grondtipes is daar gevind dat die persentasie mucoraliese fungi op die plate toegeneem het van somer tot winter. Daarby was die aantal waarneembare Morlierella subgenus Morlierella op die plate meer in die winter as in die laatsomer. Die diversiteit van mucoraliese spesies wat in die winter uit fynbos- en wingerdgrond verkry is, was beduidend minder as die diversiteit van dié spesies in Alti Berg-Grasland grond. Om te bepaal of die Morlierella subgenus Morlierella isolate van die fynbos- en wingerdgrond en dié van Alti Berg-Grasland van mekaar verskil ten opsigte van hul vermoë om by lae temperature te groei, is die radiale groeitempo op moutekstrak by 4"C en aoc vir elke isolaat bepaal. Die resultate dui aan dat daar nie alleen seisoenale veranderinge in die taksa binne Morlierella subgenus Morlierella voorkom nie, maar dat die isolate wat tydens verskillende seisoene uit die grond verkry is, ook ten opsigte van hul groeivermoë by lae temperature van mekaar verskil. Die persentasie isolate wat groter kolonie diameters bereik het ná B dae inkubasie by 4°C, was hoër vir die isolate van die koue, nat Juliemaand as vir dié wat in die warmer en droër Februariemaand verkry is. Soortgelyke resultate is verkry met radiale groei-eksperimente wat by BOC gedoen is. Die MortierelIa subgenus MortierelIa isolate wat in die winter uit fynbos- en wingerdgrond verkry is, het In kleiner variasie in hul groeitempo by lae temperature getoon as die isolate in dié takson wat tydens 'n vorige studie in die winter uit Alti Berg-Grasland grond verkry is. Dié variasie stem ooreen met die groter aantal (20) MortierelIa subgenus MortierelIa spesies wat in die graslandgrond gevind is. Slegs sewe spesies van dié subgenus is gedurende die huidige studie in die fynbos- en wingerdgrondmonsters waargeneem. Daar is gespekuleer dat dié verskil in diversiteit tussen die fynbos- en wingerdisolate en die graslandisolate van die vorige studie die gevolg mag wees van verskille tussen die habitat of die enumerasiemetodes wat gebruik is. Die filogenetiese verwantskap tussen verskillende psigrotolerante isolate van MortierelIa subgenus MortierelIa uit die grond van die fynbos, wingerd en Alti Berg-Grasland, is vervolgens bepaal deur 'n vergelyking van interne getranskribeerde spasieerder (ITS) areas, binne ribosomale RNS herhalings. Daar is gevolglik 45 psigrotolerante MortierelIa subgenus MortierelIa isolate uit die drie grondhabitatte met mekaar vergelyk op grond van die basis ITS 1 nukleotied opeenvolgingsamestelling en radiale groeitempo by 4°C. Filogenetiese analises het die isolate in twee groepe verdeel op grond van hul vermoë om by lae temperature te groei. Elke groep is verder in twee subgroepe verdeel. Daar is gevind dat behalwe vir een subgroep en die verwysingstam wat in 'n ander subgroep voorgekom het, elkeen van die subgroepe bestaan het uit isolate wat van 'n enkele grond habitat verkry is. Dit wil dus voorkom of die ITS 1 opeenvolging van dié fungi 'n aanduiding gee van die oorspronklike habitat en die vermoë om by lae temperature te groei. Dié korrelasie tussen die ITS opeenvolging en die ekologiese habitat van 'n fungus is ook deur ander werkers vir ander fungusgroepe waargeneem.

Thesis (MScAgric)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The study was conducted in the Western Cape Province to investigate the effect of soil preparation on selected soil physical properties. This study was necessitated by the negative effects that high soil bulk density has on the growth and production of a vine. Soil preparation in South Africa are applied to remove root limiting layers in the subsoil and to create a larger soil volume for root growth. The question is whether it is always necessary because of the destruction of macropore structure and also the high costs that is involved. The study includes different soil forms, different depths of tillage, different tillage operations and also the change of soil physical properties with time. Soil physical properties that was investigated include, bulk density (cloth method), infiltration (mini disk infiltrometer and double ring infiltrometer), shear strength (pocket vane tester), soil strength (penetrometer) and root distribution (profile wall method). The main finding was that the positive effects of soil preparation were still clear after 25 years. The bulk density, shear strength, penetration resistance and infiltration with the double ring infiltrometer of the deeper soil preparation practices were considerably lower than those of undisturbed soil. Soil preparation shallower than 60 cm recompacted more than the deeper tillage treatments. Hydraulic conductivity with the mini disk infiltrometer yielded mixed results. This was mainly because measurements represented hydraulic conductivity through the whole profile and therefore can be influenced by many factors. Root distribution has increased with depth of tillage and the effect was clear at Nietvoorbij in the deeper (> 60 cm) soil preparation treatments. There were no significant difference between the two soil preparation methods (delve plough and soilmix) at Kanonkop, although the effect of secondary compaction by the soilmix was quite clear. Recompaction over a year was clear in the 2009 and 2010 tillage treatments at Broodkraal. The methods that were used to determine the soil physical properties have all yield good results. At all the sites the tillage treatments generally yielded better results than the undisturbed soils. It was also clear that the longer the time after tillage the smaller become the difference between the tillage treatments and the undisturbed soils. Recompaction did occur and therefore soil preparation might possibly be applied again before new vines wants to be planted. / AFRIKAANSE OPSOMMING: Die studie is in die Wes-Kaap Provinsie gedoen om die effek van grondvoorbereiding op geselekteerde grondfisiese eienskappe te ondersoek. Hierdie studie is genoodsaak deur die nadelige gevolge wat hoë gronddigthede op die groei en produksie van ’n wingerdstok het. Grondvoorbereiding in Suid-Afrika word toegepas om beperkende lae in die ondergrond te verwyder en sodoende ‘n groter grondvolume vir wortelgroei beskikbaar te stel. Die vraag is egter of dit altyd noodsaaklik is weens die vernietiging van voorkeur vloeikanale en die hoë kostes wat daarmee gepaard gaan. Die studie sluit verskillende grondvorms, verskillende dieptes van bewerking en verskillende tipes bewerking in asook hoe die toestande met verloop van tyd verander. Grondfisiese eienskappe wat ondersoek is, sluit in: bulkdigtheid (kluitmetode), infiltrasie (“mini disk” - en dubbelring infiltrometer), skuifsterkte (skroefbladmeter), grondsterkte (penetrometer) en wortelverspreidings (profielwand metode). Die studie is uitgevoer by drie verskillende proeflokaliteite, nl. Nietvoorbij, Kanonkop en Broodkraal. Die vernaamste bevindings was dat die grondvoorbereidingsbehandelings se voordelige effek oor die langtermyn, na 25 jaar, steeds duidelik waarneembaar was. Die bulkdigtheid, skuifsterkte, penetrasieweerstand en infiltrasie met dubbelring infiltrometer van die dieper grondbewerkingspraktyke was aansienlik laer as die kontrole behandelings (onversteurde grond) gewees. Die grondvoorbereidingsaksies vlakker as 60 cm het tot ʼn mate weer herverdig. Hidrouliese geleiding met minidisk infiltrometer het baie wisselvallige resultate opgelewer. Dit is hoofsaaklik omdat die meting die geleiding deur die hele profiel verteenwoordig en daar baie faktore is wat dit kan beïnvloed. Die wortelverspreiding het met diepte van grondbewerking toegeneem en die langtermyn voordelige effek was duidelik by Nietvoorbij in die dieper (> 60 cm) grondvoorbereidingsbehandelings sigbaar. Die twee grondvoorbereidingspraktyke (dolbewerking en “soilmix”) by Kanonkop het nie betekenisvol van mekaar verskil nie, alhoewel die effek van sekondêre kompaksie soos veroorsaak deur die “soilmix” implement, duidelik was. Herverdigting oor die tydperk van ’n jaar was duidelik tussen die 2009- en 2010 bewerking by Broodkraal. Die metingsmetodes waarmee die grondfisiese eienskappe ondersoek is, het almal goeie resultate gelewer. By al die proeflokaliteite het die bewerkingsbehandelings oor die algemeen beter resultate as die kontrole-behandelings (onversteur) gelewer. Hoe langer die tydperk na grondvoorbereiding hoe kleiner was die verskil tussen die bewerkingsbehandelings en die kontrole. Herverdigting het wel voorgekom en daarom sal grondvoorbereiding moontlik weer toegepas moet word wanneer nuwe aanplantings gemaak word.

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Cabernet Sauvignon is the most planted red cultivar in South Africa and the second most planted red cultivar in the Olifants River region. The cultivar is prone to vigorous growth with low yields. Excessive irrigation could accentuate these cultivar characteristics. Considering the foregoing, the aim of the study was to describe how Cabernet Sauvignon will react to climate, soil type (texture) and irrigation within the Lower Olifants River wine region to enable growers to make the right decisions regarding long term as well as short term cultivation practices. This study is part of a project carried out by the ARC Infruitec-Nietvoorbij at Stellenbosch to determine the effects of soil type and atmospheric conditions on yield and wine quality of Cabernet Sauvignon in different grape growing regions of South Africa. Similar studies are being carried out in the Orange River, Stellenbosch and Swartland regions of South Africa. The Lower Olifants River region could be divided into three climatic regions. Furthermore, two climatic regions is evident regarding the formation of grape wine colour and aromas. Proximity to the Atlantic Ocean would play an important role in a cultivar establishment policy. The variation in stem water potential (ΨS) could be related to soil water status expressed in terms of matric potential (ΨM). In the case of sandy soils, ΨS decreased substantially more as the ΨM decreased compared to the sandy loam soils. The reason could be that the unsaturated hydraulic conductivity in sandy soils decreased more rapidly as the ΨM decreased compared to the heavier soils. Thus could explain why the grapevines in the sandy soils experienced more water stress than the ones in the sandy loam soils at a given ΨM. Climate had a strong influence on grapevine water status with grapevines nearer to the ocean experiencing less water stress compared to the ones further inland. This was especially true for grapevines in the sandy soils. Vegetative growth and yield of grapevines in the sandy soils were more sensitive to water deficits compared to the ones in the sandy loam soils. For deficit irrigated grapevines in the sandy soils, vegetative growth and yield decreased by ca. 30% when ca. 55% less water was applied from flowering to harvest. Yield reduction were ca. 15% with no or very little influence on vegetative growth with ca. 80% reduction in water applied from flowering to harvest for grapevines in the sandy loam soils. The influence of soil texture on wine quality and style were evident under intensive irrigation as well as over different climatic regions. Overall sensorial potential wine quality of grapevines in sandy soils tended to be higher compared to the ones in the sandy loam soils. Deficit irrigation tended to increase wine colour intensity, irrespective of soil texture. Furthermore, deficit irrigation in sandy loam soils tended to increase wine fullness and the berry characteristics of the wine. Berry characteristics of wines from the sandy soils tended to be higher compared to the ones from the sandy loam soils. Too severe water deficits in sandy soils could be detrimental to wine quality. Climate tended to have an influence on wine style of grapevines in the sandy soils with wines produced further away from the ocean tended to have higher berry characteristics. Irrigation management could be a powerful tool to manipulate the grapevine in sandy soils. For grapevines the sandy loam soils in addition to regulated deficit irrigation, additional canopy management practices could be needed to improve wine quality. / AFRIKAANSE OPSOMMING: Cabernet Sauvignon is die mees aangeplante rooidruif kultivar in die Suid-Afrikaanse wynbedryf. In die Olifantsriver streek is dit naas Shiraz, die tweede mees aangeplante rooidruif kultivar. Cabernet Sauvignon is bekend as ‘n groeikragtige skaamdraer. Indien oorbesproei word, kan hierdie potensiële nadelige eienskappe nog meer na vore tree. Die doel van die studie is om die invloed van die klimaat, grond en besproeiing op Cabernet Sauvignon se vegetatiewe groei, produksie en wyngehalte in die Benede Olifantsrivier streek te bepaal. Hierdie inligting kan produsente help om ingeligte kortsowel as langtermyn besluite te maak rakende die verbouing van Cabernet Sauvignon. Hierdie studie vorm deel van ‘n breër studie in die Suid-Afrikaanse wynbedryf, gedryf deur die Landbou Navorsingsraad (LNR) Infruitec-Nietvoorbij, Stellenbosch om die invloed van atmosferiese toestande en grond op die produksie en wyngehalte van Cabernet Sauvignon te bepaal. Soortgelyke projekte word uitgevoer in die Oranjerivier, Stellenbosch en Swartland wynstreke. Die Benede Olifantsrivier streek kan verdeel word in drie klimaatstreke op grond van temperatuurdata. In terme van die ontwikkeling van druifkleur en aromas, kan die streek verdeel word in twee klimaatstreke. Die afstand vanaf die Atlantiese Oseaan kan ‘n belangrike rol speel in die ontwikkeling van ‘n kultivarriglynplan vir die streek. Grondwaterstatus, uitgedruk as die matrikspotensiaal (ΨM), kan aanleiding gee tot variasie in middag blaarwaterpotensiaal (ΨS) lesings. Die ΨS van die sand gronde verlaag vinniger soos die ΨM verlaag invergelyke met die sandleem gronde. Dit kan moontlik wees as gevolg van die verskil in die grond onversadigde hidroliese konduktiwiteit. Sand gronde se hidroliese konduktiwiteit verlaag vinniger soos die ΨM verlaag, invergelyke met sandleem gronde. Dit verklaar waarom wingerde in sand gronde by dieselfde ΨM, meer waterspanning ondervind as wingerde in sandleem gronde. Klimaat het ‘n invloed op die waterstatus van die wingerdstok. Wingerde nader aan die see het minder waterspanning ondervind invergelyke met wingerde wat verder in die binneland geleë is. Dit was veral die geval met wingerde in die sand gronde. Vegetatiewe groei en produksie van wingerde in die sand gronde is meer sensitief vir waterspanning as wingerde in die sandleem gronde. Tekortbesproeiing in die sand gronde het die groei asook produksie met ongeveer 30% verlaag deur ongeveer 55% minder water toe te dien vanaf blom tot oes. In teenstelling daarmee is die produksie van wingerde in die sandleem gronde met ongeveer 15% verlaag met geen tot baie min verlaging in die groeikrag. Ongeveer 80% minder water is toegedien vanaf blom tot oes. Grondtekstuur kan wyngehalte en -styl beïnvloed ten spyte van intensiewe besproeiing en klimaatsverskille. Sensoriese potensiële wyngehalte van wingerde in die sand gronde was beter invergelyke met dié van die sandleem gronde. Die wyne vanaf die sand gronde het ook geneig om oor meer bessie intensiteit te beskik as wyne vanaf die sandleem gronde. Tekortbesproeiing neig om die wynkleur intensiteit te verhoog, ongeag van grondtekstuur. Tekortbesproeiing in die sandleem gronde kan ook die volheid van die wyne verbeter, asook die bessie intensiteit van die wyn verhoog. Te hoë waterspanning in die sand gronde kan wyngehalte nadelig beïnvloed. Klimaat kan ook die wynstyl vanaf sand gronde beïnvloed met wyne verder vanaf die see wat oor meer bessie intensiteit beskik as wyne nader aan die see. Beheerde tekortbesproeiing kan as ‘n kragtige hulpmiddel gebruik word om wingerde in die sand gronde te manipuleer. Vir wingerde in die sandleem gronde, addisioneel tot beheerde tekortbesproeiing en normale loofbestuurspraktyke, kan ekstra loofbestuurspraktyke bv. die verwydering van sylootlote, dalk nodig wees om wyngehalte te verbeter.

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosach, 2010. / ENGLISH ABSTRACT: Cabernet Sauvignon, the most planted red wine cultivar in South Africa, is prone to vigorous growth with low yields. The aim of the study was to describe how Cabernet Sauvignon grapevines react to climate and irrigation within the Swartland region. Such knowledge would assist growers in decisions regarding long term as well as short term cultivation practices. This study was part of a larger project carried out by the Infruitec-Nietvoorbij institute of the Agricultural Research Council at Stellenbosch to determine effects of soil type and climate on yield and wine quality of Cabernet Sauvignon. The larger project was carried out in selected grape growing regions, i.e. Stellenbosch, Swartland, Lower Olifants River and Lower Orange River. Due to the proximity to the Atlantic Ocean, the study area in the Swartland region could be divided into two climatic regions for viticulture. Grapevines near Philadelphia closer to the ocean experienced less water constraints compared to those further inland near Wellington. Variation in stem water potential could also be related to soil water matric potential. Climate tended to have a more pronounced effect on the grapevine response to water constraints further inland than closer to the ocean. Vegetative growth, berry size and yield depended on water constraints experienced by the grapevines. In the warmer climate, severe constraints reduced yield. In the warmer climate, grapes started to ripen earlier than those in the cooler climate. Sugar concentration (mg/mL) was highest where grapevines experienced moderate water constraints. These seemingly balanced grapevines had the highest sugar accumulation, probably due to optimum photosynthesis and carbohydrate utilization. Low water constraints increased vegetative growth which could have been a sink for sugar loading. In addition to sugar loading, degree Balling (°B) increases could also have been due to a concentration effect where water constraints reduced berry volume. Therefore, °B is probably not a representative indicator of grapevine functioning. Anthocyanin biosynthesis, as quantified on a per berry basis, showed that sugar and anthocyanin could be co-regulated, with anthocyanin biosynthesis reaching a plateau when the sugar content per berry reached 200 mg/mL to 220 mg/mL. At véraison, the most intense grape colour occurred where grapevines experienced moderate water constraints, i.e. single drip line at Wellington and no irrigation at Philadelphia. However, at harvest grapes from the cooler climate tended to have more intense colour and higher phenolics, indicating that lower temperatures favoured anthocyanin biosynthesis. These results supported earlier findings that grapevine water status influences berry volume and dynamics of berry ripening. Water constraints tended to increase sensorial wine colour intensity, as well as wine fullness. Moderate water constraints at both localities resulted in the best sensorial wine quality. Yet there were indications that too severe water constraints could be detrimental to wine quality. Irrigation can be used to manipulate grapevine growth in warmer climates, but might be less effective in cooler climates. In warmer climates, moderate water constraints required to achieve balanced grapevine functioning can be obtained with single drip irrigation, but this might not be the case in cooler climates. / AFRIKAANSE OPSOMMING: Cabernet Sauvignon, die mees aangeplante rooiwynkultivar in Suid-Afrika, is geneig tot kragtige groei met lae opbrengste. Die doelwit van hierdie studie was om te beskryf hoe Cabernet Sauvignon-wingerdstokke reageer op klimaat en besproeiing in die Swartland-streek. Hierdie kennis sal kwekers help wanneer hulle besluite moet neem oor langtermyn sowel as korttermyn verbouingspraktyke. Hierdie studie was deel van ‘n groter projek deur die Infruitec-Nietvoorbij Instituut van die Landbounavorsingsraad op Stellenbosch om die effekte van grondtipe en klimaat op die opbrengs en wynkwaliteit van Cabernet Sauvignon te bepaal. Die groter projek is in geselekteerde wingerdverbouingstreke uitgevoer, nl. Stellenbosch, Swartland, Benede Olifantsrivier en Benede Oranjerivier. As gevolg van die nabyheid daarvan aan die Atlantiese Oseaan kon die studiegebied in die Swartland-streek in twee klimaatstreke vir wingerdbou verdeel word. Wingerdstokke by Philadelphia, wat nader aan die oseaan is, het minder waterstremming ervaar as dié verder binnelands naby Wellington. Veranderinge in stamwaterpotensiaal hou moontlik ook verband met die grondwater- matrikspotensiaal. Klimaat het ‘n groter effek op die reaksie van die wingerdstok op waterstremming verder binnelands as nader aan die oseaan. Vegetatiewe groei, korrelgrootte en opbrengs was afhanklik van die waterstremminge wat deur die wingerdstokke ervaar is. In die warmer klimaat het die ernstige stremminge opbrengs verminder. In die warmer klimaat begin druiwe vroeër ryp word as in die koeler klimaat. Suikerkonsentrasie (mg/ml) was die hoogste waar wingerde matige waterstremming ervaar het. Hierdie skynbaar gebalanseerde wingerdstokke het die hoogste suikerakkumulasie vertoon, moontlik as gevolg van optimum fotosintese en koolhidraatverbruik. Lae waterstremming het vegetatiewe groei verhoog, wat ook ‘n vraagpunt vir suikerlading kon wees. Benewens suikerlading kon verhogings in grade Balling (°B) ook moontlik aan ‘n konsentrasie-effek toegeskryf word in terme waarvan waterstremming die korrelvolume verminder het. °B is dus moontlik nie ‘n verteenwoordigende indikator van wingerdstokfunksionering nie. Antosianienbiosintese, soos gekwantifiseer op ‘n per-korrel basis, het getoon dat suiker en antosianien saam gereguleer kon word, en dat antosianienbiosintese ‘n plato bereik het wanneer die suikerinhoud per korrel 200 mg/mL tot 220 mg/mL was. By deurslaan het die mees intense druifkleur voorgekom waar die wingerdstokke matige waterstremming ervaar het, d.w.s. enkel druplyn op Wellington en geen besproeiing op Philadelphia. Teen oes was die druiwe in die koeler klimate egter geneig om meer intense kleur en meer fenole te bevat, wat aandui dat laer temperature antosianienbiosintese bevoordeel. Hierdie resultate ondersteun vroeër bevindings dat die waterstatus van die wingerdstok ‘n invloed op korrelvolume en die dinamika van korrelrypwording het. Waterstremming neig om die sensoriese wynkleurintensiteit te verhoog, asook die volheid van die wyn. Matige waterstremming op beide liggings het aanleiding gegee tot die beste sensoriese wynkwaliteit. Tog was daar aanduidings dat waterstremming wat te straf was, nadelig kon wees vir wynkwaliteit. Besproeiing kan gebruik word om wingerdgroei in warmer klimate te manipuleer, maar is moontlik minder effektief in koeler klimate. In warmer klimate kan die matige waterstremming wat benodig is vir gebalanseerde wingerdstokfunksionering, verkry word deur enkel drupbesproeiing, maar dit is moontlik nie die geval in koeler klimate nie.

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2011. / Includes bibliography. / ABSTRACT: The grapevine must constantly find a balance between two continually changing environments, the rhizosphere (i.e. soil) and the troposphere (i.e. macroclimate). The adaptations are extremely complex because they encompass complicated and interrelated processes that are not yet fully understood. In terms of water-use behaviour, differences between cultivars have been described in the literature. In this study, the water status and stomatal conductance of four cultivars (Shiraz, Grenache, Pinot noir and Chardonnay) grafted onto R99 were studied. Diurnal cycles of water status and stomatal conductance, from 07:00 to 19:00, were followed for a single day at the end of the 2009 season. The results showed that, at the end of the season, Shiraz was subjected to water stress conditions, losing leaves and showing symptoms of berry shrivelling. The other three cultivars had a much better canopy status and no symptoms of berry shrivelling were observed. Based on the canopy observations and a comparison of the curves of stem water potential (Ψs) and stomatal conductance (gs), it seems that Pinot noir and Chardonnay are closer to the water-use behaviour of Grenache noir, which is known as a “pessimistic” cultivar, than to Shiraz, which is an “optimistic” cultivar. A study of four plots each of Chardonnay/101.14 Mgt and Shiraz/101.14 Mgt was carried out in eight commercial vineyards in the Robertson region in order to investigate the relationship between soil and root morphology, and the influence thereof on canopy development and berry growth. These plots had different soil types. Important soil properties are reported to limit root growth, individually or as a combination of restrictions. It was found that the size of the root system of 101.14 Mgt is defined by soil physical and chemical properties. The roots of 101.14 Mgt under irrigation can grow to a depth of 100 cm or beyond if the soil physical and chemical properties allow it. Because the soil properties define the root system and the water storage/drainage, they greatly influence the plant water status, even under irrigation. In an arid zone like Robertson, irrigation is an important management tool. The balance between canopy growth before véraison and the ability of the root-soil system to maintain that canopy size during the ripening process is crucial in an area with a high evaporative demand. In this regard, not all the soil properties-root system combinations showed satisfactory performance in maintaining the canopy functioning, which affected berry sugar loading and berry volume. In another study that is presented, forty soil profiles were characterised in the Robertson valley. The root systems were considered as a product of the soil properties, and thus the morphology of the root systems was used as a starting point to group soils together. The importance of soil depth has been described well, thus the root systems were first classified according to rooting depth – into shallow and deep root systems. The deep root systems were then subdivided, creating two subgroups of high root density and low root density. The two extreme groups (i.e. shallow roots, and deep roots with high root density) have particularly different soil properties. The soil characteristics found in these extremes are represented up to certain point by families of the South African soil taxonomy, mainly due to the restrictive function of the B horizon. This restrictive function is related to soil properties that are taken into consideration in the South African soil classification and that are important for grapevine root growth, as well as the thickness of the described horizons and the physical and chemical differences between the horizons. Soil properties have an important influence on root morphology. Due to the fundamental role played by the root system in the overall plant functioning, soil properties are of critical importance. In an arid area, the low water pressure in the atmosphere and the high temperature greatly affect the plant water status. The soil-root system combination plays an important role in the ability of the root system to supply the plant with water during times of high evaporative demand. Different cultivars will react differently due to differences in transpiration control. The maintenance of an adequate water status will have an immense influence on canopy development and maintenance, and on normal and steady berry ripening. In this study it was found that not all the soil-root combinations can fulfil this satisfactorily. Thus, the grapevine balance determined by the combination of the soil-root-canopy complex and the influence of management techniques is extremely important for the favouring of a good canopy:root system ratio, a functional canopy throughout the season and a steady berry ripening curve.

This diploma thesis focuses on the issue of public life on Royal Vineyards in the period of 1880 - 1922. First of all, particular factors that form the image (character, identity) of Royal Vineyards as czech, healthy, modern and independent city with historical tradition, inhabited mainly by middle class population, are analysed. Further more the thesis is discussing czech public life on Vineyards. By the term public life is here meant an analysis of the formation and appearance of vineyard public spaces and cultural facilities and their importance for residents of Vineyards. Thesis is looking into the function of these spaces as a meeting place for various occasions (eg. holding of festivities, place of associational life, leisure activities). In other chapters german and jewish minorities are closer analyzed. Here the thesis focuses on the character of public life of these communities and their coexistence with Czechs. Examined is, among others, the question which aspects that shape the character of Vineards are the particular groups of residents identified with and which of them they considered as their own and how they have symolically inhabited them. Key words: Royal Vineyards, public spaces, festivities, local identity, Czechs, Germans, Jews, 1880 - 1922.

Les nombreux mouvements de terrain qui affectent les versants du vignoble champenois sont à l'origine de coûteux dégâts. Les causes de leur déclenchement restent cependant indéterminées. Basé sur une méthodologie pluridisciplinaire, ce travail de recherche vise à comprendre l'origine et le fonctionnement de ces désordres. A l'échelle régionale, deux grands ensembles se distinguent et mettent en avant le rôle de la structure sur les dynamiques géomorphologiques. Au nord, la cambrure de versant domine. D'âge antésaalien, elle s'est produite en phase ana et/ou cataglaciaire. Au sud, dans le secteur de la vallée de la Marne et de ses affluents, 264 glissements de terrain, d'âge tardiglaciaire pour la plupart, sont recensés. A l'échelle du bassin versant, les glissements de terrain se situent dans les secteurs à fort rendement hydrologique. En retour, leur présence modifie la répartition spatiale des sources : les plus profonds constituent une couverture semi-perméable déterminant un aquifère semi-captif. A l'échelle locale, les investigations géophysiques et piézométriques permettent de modéliser les relations hydrogéologiques entre formations superficielle et substrat. Il apparait que les glissements ont une structure très hétérogène, que les circulations d'eau y sont réduites et ralenties dans la masse du mouvement, et enfin que les échanges avec le substrat se produisent le long du plan de cisaillement. Dans ces conditions, l'influence des facteurs climatiques actuels sur la réactivation des glissements est indirecte et faible. / The numerous mass movements affecting the Champagne vineyards slopes cause expensive damages. However, triggering factors are still unknown. Using a multidisciplinary methodology, this research aims to understand the origin and the behavior of these instabilities. At a regional scale, two major groups are distinguished and show the importance of the geological structure on the geomorphological dynamics. Northwards, valleyside cambering of pre-Saalian age predominates. It took place during ana and/or cataglacial phase. Southwards, in the Marne valley and its tributaries area, 264 landslides, most of them dating from Tardiglacial period, are inventoried. At the watershed scale, areas with a high quantity of landslides correspond to the sectors of high hydrological yields. In return, the presence of landslides alters the spatial distribution of springs: deepest landslides constitute a semi-permeable cover leading to semi-confined aquifers. At the local scale, geophysical and piezometric investigations make it possible to model the hydrogeological relationship between superficial formations and substratum. It appears that landslides structure is heterogeneous, that the circulation of water is limited and slow in the landslide, and that the exchanges with substratum occur along the shear plan. Under these conditions, the influence of climatic factors on the current reactivations is both indirect and weak.

Vineyards in New Zealand suffer bird damage caused by several avian species, including blackbirds and silvereyes. The introduced European Blackbird takes whole grapes which reduces yield. The self-introduced Australasian Silvereye pecks on grapes, leaving them on the vine to be further attacked by fungi and bacteria, and the subsequent off-odours can cause grapes to be refused by the winery or to suffer a price-reduction. Bird control methods remain primitive and largely ineffective during the long ripening period of wine grapes. An ecologically sound method to manage and reduce bird pressure requires deeper understanding of why some birds eat grapes, especially since grapes are not particularly nutritious. This work investigated the extent to which blackbirds and silvereyes are attracted by various compounds in ripening grapes. Since in natural grapes these compounds develop and change simultaneously, I developed an artificial grape in which a single parameter could be investigated. Artificial grapes (and sometimes nectar) were presented on a bird feeder table and the responses of birds to hexose sugars, the aromas 2-3-isobutylmethoxypyrazine and geraniol, tartaric and malic acids, grape tannins, and purple and green colour were recorded on timelapse video and analysed.