Thesis (MscAgric (Horticulture))--University of Stellenbosch, 2008. / ‘Brookfield Gala’ apple trees were planted out in July 2003 in a Dundee soil form, consisting of well-aerated sandy loam soil. During the first 12 months trees received young tree solutions high in nitrogen. The nutrient solution of the 2nd leaf trees was based on a yield estimation of 10 ton. ha-1 plus 30%. Nutrient solutions for the 3rd leaf trees were based on 25 ton. ha-1 yield estimations and adapted upwards. Seasonal uptake and distributions were determined for macro and micro elements, using twoand three-year-old apple trees during the seasons 2004/2005 and 2005/2006. In the bearing apple trees the macro nutrient accumulated rapidly from late winter to late autumn. Prior to leaf drop most of the N, P, S, Mg and a small portion of K were redistributed back into the permanent parts of the tree. On the other hand, all Ca in the leaves was lost through leaf drop. Apple fruit contains comparatively large quantities (±60.2%) of K, which are removed during harvest. Guidelines for minimum and maximum nutritional requirements based on the amount necessary to produce 1 kg fruit were determined. For the 3rd leaf trees the minimum macro nutrient requirements (g. kg-1 yield) of N, P, K, Ca, Mg and S were ±1.7, ±0.3, ±2.3, ±0.5, ±0.2 and ±0.2, respectively. The maximum nutrient requirements (g. kg-1 yield) for N, P, K, Ca, Mg and S were ±2.6, ±0.4, ±3.3, ±1.9, ±0.4 and ±0.2, respectively. For the 3rd leaf trees the minimum micro nutrient requirements (mg. kg-1 yield) of Na, Mn, Fe, Cu, Zn, B and Mo were ±75.1, ±1.3, ±28.7, ±0.9, ±3.0, ±5.7 and ±0.3, respectively. The maximum nutrient requirements (mg. kg-1 yield) of Na, Mn, Fe, Cu, Zn, B and Mo were ±102.9, ±7.8, ±32.6, ±1.1, ±6.5, ±7.6 and ±0.3, respectively. Labelled N uptake and distribution for two- and three-year-old apple trees were also determined during the same seasons. The labelled N uptake and distribution results indicated that there was a low labelled N uptake in the initial growth stages, suggesting the importance of internal N reserves for plant development at the beginning of the season. In the active growing period more than 60% of the labelled N was found in the new growth. Uptake efficiency improved as the trees grew older. The effect of different nutrient levels on tree growth, yield and fruit quality was assessed: lower (80%) than the standard (100%) and three higher (120%, 140% and 160%). Results indicated that different nutrient levels had no effect on yield, blush or TSS during the 18 months of application over two bearing seasons. The application of biological products (humic acid, and compost plus compost extract) over a period of 18 months had a significant influence on the TSS, malic acid and citric acid concentrations. A tendency towards an increase in total fine root number and length occured with the addition of biological ameliorant.

Thesis (MscAgric (Horticulture))--University of Stellenbosch, 2008. / Commercial production of sweet cherries has recently increased in South Africa, with more than 400 ha planted by 2006. Cherry, a high chilling fruit variety, is however not suited for the mild winter climate of South Africa. This was recognizable through common observed symptoms of delayed foliation and poor fruit set. In addition, cherry is exposed to long and hot summers in the postharvest period. The objective of this study was to evaluate cherry cultural practices that can manipulate (reduce) the trees chilling requirement under South African conditions. Cultural practices where aimed at increasing reserves (nitrogen, cytokinin and carbohydrates) in the tree. In addition, bud dormancy progression of cherry buds was quantified to determine the bud dormancy progression pattern under mild winter conditions. This was achieved through sampling of cherry shoots from different cherry production areas which was then forced in the growth cabinets. A model was developed to identify possible factors and groupings that can explain the cherry bud dormancy pattern. A model, comprising two joined straight lines, was fitted in order to characterize bud dormancy behaviour for sweet cherry cultivars under mild winter conditions. All cherry cultivars followed the expected pattern of entrance and exit from dormancy. Factor analysis showed that factors related to the entrance into dormancy primarily characterize bud dormancy behaviour. Bud dormancy patterns were also a function of environmental conditions within a year as shown by cluster analysis. In addition, buds entered dormancy in mid-summer and remained dormant until chilling accumulation commenced. Bud dormancy release was generally extended over a three to five-month period for all cultivars. Prior to spring budburst exit of both lateral and terminal buds occurred rapidly. Data indicate that there is no ecodormant phase for cherry under the prevalent climatic conditions in South Africa. Further experimentation was aimed at increasing reserves within the trees through cultural practices. In the nitrogen trials, fertilization in the postharvest period had no significant effect on field budburst or bud dormancy progression in one-year-old shoots. Time of flowering was advanced in N treatments during 2007 only. Yield was not significantly increased. Therefore, in this trial, N fertilization in the postharvest period did not significantly reduce the chilling requirement of mature sweet cherry trees under mild winter conditions. Application of particle films (Surround® and Raynox®) or ethylene inhibitors (Retain®) in the summer did not reduce the heat stress the trees experienced. Treatments had no significant effect on carbon assimilation, stomatal conductance, leaf surface temperature, fluorescence, bud dormancy, budburst, flowering and fruit set. Cytokinins sprays (benzyladenine) in autumn did not affect bud dormancy progression, spring budburst or flowering. Hydrogen cyanamide application in spring significantly advanced budburst, time to full bloom and increased yield. Promalin® and Retain®, however, had no significant effect on budburst, flowering or yield. It is therefore evident that cherry, due to its unexpected bud dormancy behaviour and its inability to be significantly influenced by several cultural practices, adapts poorly to South African climatic conditions through not reducing its chilling requirement significantly.

Thesis (MscAgric (Horticulture))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Experiments were conducted to increase the percentage class one ‘Granny Smith’ and ‘Cripps’ Pink’ apples. ‘Granny Smith’ is the most widely grown apple cultivar in South Africa, but its profitability is compromised by the high incidence of sunburn, red blush and poor green colour development. ‘Cripps’ Pink’ is a very lucrative cultivar and producers are striving to maximise the production of fruit that qualify for export. Fruit technologists and growers are debating whether it is best to maximise class one fruit in ‘Cripps’ Pink’ by increasing total yield or by increasing fruit quality. The relationship between ‘Granny Smith’ canopy position and external fruit quality was investigated. Light exposure, peel temperature, green colour development, sunburn and red blush development was followed for individual fruit from the outer, intermediate and inner canopy. Dark green fruit were exposed to moderate to high light levels (25-50% full sun) during the first half of fruit development, similar to fruit that eventually developed sunburn and red blush. The difference came in during the latter half of fruit development when dark green fruit became shaded (3% full sun). Pale green fruit contained less chlorophyll due to consistent low light levels (2% full sun). Fruit at partially shaded canopy positions had a lower occurrence of sunburn and red blush than outside fruit and better green colour development than fruit from the heavily shaded inner canopy. Based on these data, pruning strategies and mulching were evaluated to alter canopy vigour and the light environment in such a way that green colour development is promoted and the occurrence of sunburn and red blush is reduced. In an older, vigorous orchard with a dense canopy, pruning was done to increase light distribution for green colour development and to induce more growth on the side of the trees that are prone to sunburn and red blush. Pruning improved green colour development without affecting sunburn or red blush. In a younger, non-vigorous orchard, pruning and mulching were used to invigorate the canopy to increase shading of fruit and thereby decrease sunburn and red blush. However, these treatments were not effective. Further research should focus on the use of shade nets, accompanied by rigorous pruning, to reduce sunburn and red blush while not decreasing green colour. Five different crop loads were established in an exceptionally high yielding (averaging over 100 ton·ha1) ‘Cripps’ Pink’ orchard by first the thinning of clusters, then the removal of small fruit and, finally, the selective removal of fruit from the shaded inner canopy. Treatments had no effect on iv fruit quality in the first season. The most severe thinning treatment increased the percentage class one fruit in the second season by increasing the number of fruit with adequate red blush. However, seen cumulatively, the higher crop loads yielded more class one fruit per hectare than the lower crop loads, without affecting reproductive and vegetative development or fruit storability. Producers should strive for the highest crop loads allowed by the fruit size limitations in cultivars that are not prone to alternate bearing / AFRIKAANSE OPSOMMING: Eksperimente is uitgevoer om die persentasie uitvoerkwaliteit ‘Granny Smith’ en ‘Cripps Pink’ appels te verhoog. ‘Granny Smith’ maak die grootste deel uit van appel aanplantings in Suid Afrika, maar die winsgewendheid daarvan word beperk deur `n hoë voorkoms van sonbrand, rooi blos en swak groen kleurontwikkeling. ‘Cripps’ Pink’ is `n baie winsgewende kultivar en produsente streef daarna om die persentasie uitvoerkwaliteit vrugte te maksimaliseer. Vrugte tegnoloë en produsente debatteer oor die wenslikheid daarvan om uitvoerkwaliteit vrugte te maksimeer deur totale produksie te verhoog of deur vrugkwaliteit te verbeter. Die verband tussen ‘Granny Smith’ draposisie in die blaredak en eksterne vrugkwaliteit is ondersoek. Ligvlakke, skiltemperatuur, groen kleurontwikkeling, sonbrand en rooi blos ontwikkeling is deur die loop van die seisoen gevolg vir individuele vrugte aan die buitekant, binnekant en intermediêre posisies binne die blaredak. Daar is gevind dat die donkerste groen vrugte, nes vrugte wat uiteindelik sonbrand en rooi blos ontwikkel het, blootgestel was aan matige tot hoë ligvlakke (25-50% vol son) gedurende die eerste helfte van vrugontwikkeling. Donker groen vrugte is egter oorskadu (3% vol son) tydens die tweede helfte van vrugontwikkeling. Vanweë konstante lae beligting (2% vol son) het binne vrugte min chlorofiel geakkumuleer en daarom is hierdie vrugte lig van kleur. Vrugte in gedeeltelike skadu ontwikkel min sonbrand en rooi blos in vergelyking met buite vrugte en toon beter groen kleurontwikkeling as vrugte in diep skadu binne die boom. Gegrond op bogenoemde resultate is die gebruik van snoei strategieë en deklae om die groeikrag en die ligomgewing van die boom te modifiseer, ten einde groen kleur ontwikkeling te bevorder en sonbrand en rooi blos te verminder, geëvalueer. In ‘n ouer, groeikragtige boord met ‘n digte blaredak is snoei gebruik om ligverspreiding te verbeter vir groen ontwikkeling en om meer groei te stimuleer aan die buitekant van die boom wat meer geneig is tot sonbrand en rooiblos. Groen kleur is wel verbeter, maar sonbrand en rooi blos is nie geaffekteer nie. In `n jonger, minder groeikragtige boord is ‘n deklaag aangebring en eenjarige lote getop, sodoende groei te stimuleer om sonbrand en rooi blos te verminder deur oorskaduwing van vrugte. Hierdie behandelings was egter nie effektief nie. Toekomstige navorsing moet fokus op die gebruik van skadunette tesame met ‘n nougesette snoei strategie om sonbrand en rooi blos te verminder sonder om groen kleur te verswak. Vyf verskillende vrugladings is geskep in `n uitermatig produktiewe (gemiddeld meer as 100 ton·ha-1) ‘Cripps’ Pink’ boord deur eers vrugtrosse uit te dun, gevolg deur die verwydering van klein vrugte en, laastens, die selektiewe verwydering van vrugte in die diep skaduwee van die binneste blaredak. Vrugkwaliteit is nie in die eerste seisoen nie deur oeslading geaffekteer nie. Die strafste uitdunbehandeling het wel die persentasie uitvoerbare vrugte in die tweede seisoen verhoog deur die aantal vrugte met voldoende rooi blos te vermeerder. Kumulatief gesien, het die hoër oesladings egter meer klas een vrugte per hektaar opgelewer sonder om die reproduktiewe en vegetatiewe ontwikkeling of die stoorvermoë van vrugte te affekteer. Produsente moet strewe na die hoogste oesladings wat toegelaat word deur vruggrootte beperkings in kultivars wat nie geneig is tot alternerende drag nie

Thesis (MscAgric (Horticulture))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Commercial fig production with popular European cultivars, Bourjasotte Noire, Col de Damme Noire and Noire de Caromb, is new to the Western Cape. Little research on fig production has been conducted in South Africa and producers are struggling to implement effective commercial practices. In order to establish practices that will maximise yield of quality fruit, the most productive one-year-old shoot lengths were identified in a phenological study. All shoot length categories evaluated in ‘Bourjasotte Noire’ (10 – 15 cm, 25 – 40 cm, 50 – 65 cm, 75+ cm) yielded fruit and will probably yield well the following season. In ‘Col de Damme Noire’, shoots longer than 60 cm seem to be suited to reproduction, yet they might produce a poor yield the following season. Shoots 10 – 20 cm long in ‘Noire de Caromb’ are productive relative to their length, while shoots 30 – 50 cm and 60 – 80 cm long are also fairly productive. Shoots longer than 100 cm produced suitable shoot lengths for yield the following season. Two experiments were conducted on ‘Bourjasotte Noire’ and ‘Col de Damme Noire’ to establish the type (Experiment 1, different intensity heading cuts) and timing (Experiment 2) of pruning cuts required to stimulate the growth of shoots of the same length as the shoots selected to be optimal for yield in the phenology study, and to reduce the expression of distal branching. In ‘Bourjasotte Noire’, removing one third of the total length of one-year-old shoots on 21 July by heading stimulated the development of more growth and longer current season shoots compared to other treatments, while reducing yield slightly. Heading back to three nodes in ‘Col de Damme Noire’ stimulated the growth of current season shoots of the optimal length established in the phenology study, while heading cuts on 30 June produced the longest average current season shoot length in ‘Col de Damme Noire’. To further address the effects of distal branching (acrotony), an experiment was conducted to establish whether rest breaking agents (RBA’s) in combination with tip-pruning can increase tree complexity by improving bud break, and whether increased complexity would increase yield in all three cultivars. A second experiment was conducted to evaluate the effects of timing RBA applications on bud break and harvest scheduling. Lift® increased the number of buds breaking in ‘Bourjasotte Noire’, while in ‘Noire de Caromb’ Dormex® and oil increased bud break. Tip-pruning increased the average shoot length in ‘Bourjasotte Noire’ and ‘Col de Damme Noire’, while causing a reduction in the amount of new growth in ‘Noire de Caromb’. Lift® applied 3 August and Dormex® applied 30 June shortened the number of days to 50% bud break in ‘Bourjasotte Noire’ and ‘Col de Damme Noire’. Both Lift® and Dormex® applied on 30 June decreased the number of days to 50% bud break and 50% harvest of the breba crop in ‘Noire de Caromb’. These treatments increased the number of fruit in both the breba and main crop of ‘Noire de Caromb’, but reduced fruit size. In conclusion, different approaches with regards to pruning needs to be followed for each cultivar to establish or maintain the optimal shoots for reproduction, while RBA’s can be used to force earlier, increased- bud break and harvest of breba fruit. / AFRIKAANSE OPSOMMING: Kommersiele verbouing van drie Europese vykultivars, Bourjasotte Noire, Col de Damme Noire en Noire de Caromb is nuut tot die Wes-Kaap. Baie min navorsing oor die verbouing van vye is al in Suid-Afrika gedoen, met die gevolg dat produsente sukkel om effektiewe kommersiële verbouingspraktyke te implementeer. ‘n Fenologiese studie van die drie kultivars is uitgevoer om vas te stel wat die mees produktiewe een-jaar-oue lootlengte is, met die doel om die opbrengs van kwaliteit vrugte te maksimeer. Al vier kategorieë wat ge-evalueer is in ‘Bourjasotte Noire’ (10 – 15 cm, 25 – 40 cm, 50 – 65 cm, 75+ cm) is gevind om geskik te wees vir huidige en volgende seisoen opbrengs. Lote langer as 60 cm is geskik vir opbrengs in ‘Col de Damme Noire’ in die huidige seisoen, maar mag in die volgende seisoen swak presteer a.g.v. die gebrekkige lengte van nuwe lote wat daarop ontwikkel. In ‘Noire de Caromb’ is gevind dat lote 10 – 20 cm lank baie produktief is relatief tot hul lengte en dat lote 20 – 50 cm en 60 – 80 cm lank ook relatief produktief is. Lote langer as 100 cm was minder produktief, maar het nuwe lote gelewer wat geskik is vir opbrengs die volgende seisoen. Twee snoei eskperimente is uitgevoer op ‘Bourjasotte Noire’ en ‘Col de Damme Noire’ om vas te stel wat die mees geskikte tipe snoeisnit (Eksperiment 1, verskillende dieptes van topsnitte) en tydstip om te snoei (Eksperiment 2) is met die doel om lote te produseer soortgelyk in lengte aan die wat in die fenologie studie uitgewys is as die produktiefste, en om moontlik die voorkoms van “kaalnekke” te verminder. In ‘Bourjasotte Noire’ is gevind dat die wegsnoei van ‘n derde van die loot op 21 Julie aanleiding gee tot meer groei, langer een-jaar-oue lote en ‘n effense afname in opbrengs. Geskikte lote langer as 60 cm kan in ‘Col de Damme Noire’ verkry word deur lote te top sodat net drie nodes oorbly. Die uitvoer van topsnitte op 30 Junie het langer gemiddelde lootlengtes tot gevolg gehad. Om die probleem van “kaalnekke” (apikale dominansie) verder aan te spreek, is ‘n eksperiment uitgevoer om vas te stel of rusbreekmiddels gekombineerd met tip-snoei gebruik kan word om kompleksiteit te vermeerder deur knopbreek te verhoog, en indien wel, of dit sal aanleiding gee tot verhoogde opbrengs in al drie kultivars. ‘n Tweede eksperiment met verskillende toedieningstye van rusbreekmiddels is uitgevoer om vas te stel of oeste geskeduleer kan word. Lift® het knopbreek verhoog in ‘Bourjasotte Noire’, terwyl Dormex® en olie knopbreek verhoog het in ‘Noire de Caromb’. Tip-snoei het die gemiddelde lootlengtes verhoog in ‘Bourjasotte Noire’ en ‘Col de Damme Noire’, terwyl dit groei verminder het in ‘Noire de Caromb’. Lift® toediening op 3 Augustus en Dormex® toediening op 30 Junie het die aanvang van 50% knopbreek vervroeg in ‘Boujasotte Noire’ en ‘Col de Damme Noire’. Beide Lift® en Dormex® toediening op 30 Junie het die bereiking van 50% knopbreek- en 50% oes vervroeg in ‘Noire de Caromb’. Hierdie behandeling het ook die aantal vrugte van die breba- en hoofoes vermeerder, maar vruggrootte verminder. Verskillende snoeibenaderings behoort dus gevolg te word om vir elke kultivar die regte lootlengtes te genereer of te onderhou, terwyl rusbreekmiddels gebruik kan word om knopbreek te vervroeg en verhoog, en om die breba oes te vervroeg.

Thesis (MScAgric)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Conyza bonariensis (flaxleaf fleabane) was reported for the first time, as a weed in California in 1893-1896. The first report of the occurrence of this weed in South Africa was made in May 1895 in Franschoek, South Africa. Paraquat resistance in C. bonariensis was first reported in the 1970s and early 1980s when resistance was observed from vineyards and citrus plantations in Egypt. More recently a report of herbicide resistance in South Africa was made in January 2003 when resistance occurred in C. bonariensis in the Breede Valley, South Africa. The resistance was to glyphosate, but recently reports of resistance to glyphosate and paraquat were received. C. bonariensis seeds were found to be positively photoblastic and germinated only under unfiltered white light and red light whilst no germination occurred under far-red light and in the dark. The optimum temperature range for C. bonariensis seed was found to be between 15 and 30°C, with no germination occurring at 0-5°C and at 35- 40°C. Optimum germination occurred at the soil surface. No germination occurred at depths of 2 cm and deeper. Although the optimum temperature range was found to be the same for the different biotypes tested. However, germination was highest in the susceptible biotype. Since farmers first reported paraquat and glyphosate resistance in C. bonariensis in the Breede Valley, South Africa, reports of resistance increase every year. Seed collected from populations suspected of being resistant to paraquat and glyphosate were obtained from the Breede Valley and screened for resistance. To determine the easiest, quickest, and most effective method to screen for paraquat and glyphosate resistance, two tests were evaluated viz. the petri dish assay method and the whoIeplant dose-response method. Both screening methods identified paraquat and glyphosate resistant biotypes. The petri dish assay method was found to be a more rapid method of screening for resistance in C. bonariensis. During this study it was found that both paraquat and glyphosate resistance does occur in the Breede Valley. The effect of growth stage on the level of herbicide resistance in C. bonariensis was tested. Herbicides other than paraquat and glyphosate were tested to determine if they could be used to control resistant C. bonariensis seedlings. The alternative herbicides tested included MCPA and Sorgomil Gold 600. The four herbicides were sprayed at different leaf stages. During the study it was found that growth stage does play an important role in the level of herbicide resistance. It was found that the control of different herbicides decreased with an increase in growth stage. The different herbicides showed varying levels of control depending on growth stage and resistant profile. Overall MCPA gave the best control at all leaf stages tested. What is gratifying was the finding that every biotype tested could be controlled by at least one of the treatments applied. This means that the producer using the most appropriate herbicide applied at the optimum application stage will be able to control most if not all the resistant populations of C. bonariensis that occur in the Western Cape. / AFRIKAANSE OPSOMMING: Conyza bonariensis (Kleinskraalhans) is vir die eerste keer as 'n onkruid gerapporteer in Kalifornia in 1893-1896. Die eerste waarneming van hierdie onkruid in Suid-Afrika is gemaak in Mei 189S in Franschoek. Parakwat weerstandbiedendheid in C. bonariensis is die eerste maal in die 1970s en vroeë 1980s waargeneem, toe weerstandbiedendheid opgemerk is in wingerde en sitrus plantasies in Egipte. Meer onlangs is 'n geval van onkruiddoder weerstandbiedendheid in Suid-Afrika aangemeld in Januarie 2003, toe 'n biotipe van C. bonariensis in die Breede Vallei weerstand-biedendheid getoon het teen 'n onkruiddoder. Die weerstand was teen glifosaat, maar onlangse berigte van weerstandbiedendheid teen glifosaat sowel as parakwat is ontvang. Daar is gevind dat die saadjies van C. bonariensis positief fotoblasties is en slegs ontkiem onder ongefiltreerde wit- en rooi lig, terwyl geen ontkieming voorkom onder ver-rooi lig en in die donker nie. Die optimum temperatuurreeks vir C. bonariensis saad is tussen IS en 30°C, met geen ontkieming wat by O-SoCen by 3S-40°C voorkom nie. Optimum ontkieming kom voor op die grondoppervlak. Geen ontkieming kom by dieptes van 2 cm of dieper voor nie. Alhoewel die optimum temperatuurreeks dieselfde is vir die verskillende biotipes wat getoets is, is daar tog 'n verskil in die persentasie ontkieming tussen die biotipes met die beste ontieming by die sensitiewe biotipe. Sedert boere die eerste geval van parakwat en glifosaat weerstandbiedendheid in C. bonariensis in die Breede Vallei, Suid-Afrika gerapporteer het, word meer gevalle van weerstandbiedendheid jaarliks aangemeld. Saad van populasies wat vermoedelik parakwat en glifosaat weerstandbiedend is, is in die Breede Vallei versamel en getoets vir weerstandbiedendheid. Om die maklikste, vinnigste en mees effektiewe metode van weerstandbiedendheidstoetsing te vind, is twee verskillende metodes van toetsing, naamlik die petribakkietoets en die heel plant dosis respons metode gebruik. Beide metodes van toetsing het parakwat en glifosaat weerstandbiedende biotipes geïdentifiseer. Daar is gevind dat die petri bakkie metode 'n vinniger manier van toetsing vir weerstandbiedendheid is. Die studie het ook bewys dat parakwat en glifosaat weerstandbiedendheid wel in die Breede Vallei, Suid-Afrika voorkom. Die effek van groeistadium op die vlak van onkruiddoder weerstandbiedendheid in C. bonariensis is ook tydens die studie getoets. Ander onkruiddoders buiten parakwat en glifosaat is getoets om te bepaal of hulle gebruik kan word vir die effektiewe beheer van weerstandbiedende C. bonariensis saailinge. Die alternatiewe onkruiddoders wat getoets is, was MCPA en Sorgomil Gold 600. Die vier onkruiddoders is gespuit by verskillende blaarstadiums. Gedurende die studie is daar gevind dat groeistadium wel 'n belangrike rol speel in die vlak van onkruiddoder weerstandbiedendheid. Die persentasie beheer van verskillende onkruiddoders neem af met 'n toename in die groeistadium. Die verskillende onkruiddoders se beheer het gewissel afhangend van weerstandbiedendheid en groeistadium. MCPA het die beste beheer by alle blaarstadiums wat getoets is getoon. Daar is ook gevind dat een of die ander van die onkruiddoders wat getoets is, gebruik kan word vir die suksesvolle beheer van onkruiddoder weerstandbiedendheid in elke biotipe wat getoets is. Dit beteken dat 'n produsent wat die korrekte onkruiddoder op die korrekte groeistadium toedien, in staat sal wees om die meeste, indien nie alle weestandbiedende C. bonariensis populasies wat in die Wes Kaap voorkom, te beheer.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2005. / The demand for protein for human and animal nutrition in South Africa is increasing and it will continuously increase. The effect of replacing soybean oilcake meal as protein source for broilers and full-fat soybean meal for weaner pigs, with different levels of sweet lupins (Lupinus angustifolius), canola oilcake and full-fat canola was examined. A basal diet with soybean oilcake as protein source was mixed with a diet using either sweet lupins or canola oilcake or full-fat canola in ratios of 100%, 67% and 33% respectively. In the broiler trial the test diets were fed for a period of six weeks with or without the enzyme Vegpro (Alltech). Pigs were fed the test diets, with and without Roxazyme® enzyme, ad libitum from 8.5 to 25 kg live weight. The fatty acid content of the fat pads of the broilers raised on the different diets was determined. The pigs were kept in the trial up to the grower- finisher phase. The fatty acid content of the carcass fat and muscle of pigs raised on the different diets was determined. The inclusion of enzymes had no effect on the growth, feed intake or feed conversion ratio of broilers fed the test diets. The provision of external dietary enzymes to the weaner pig diets failed to improve either dry matter intake or growth rate, but improved the feed conversion ratio. Broiler weights at six weeks of age were significantly higher for the control diet compared to the 20% lupin diet. There was no significant difference in the feed intake as the lupin content of the diets increased. The feed conversion ratio did not differ significantly between the control diet and the 6.6% lupin diet but became significantly poorer as the lupin content increased to 13.2% and 20% of the test diet. There were no significant differences in production performance of the control diet and the canola oilcake containing diet. The broiler weights at six weeks decreased significantly with each increase in the canola oilcake content of the diets. The feed intake of the 20% canola oilcake diet at week six was significantly less than the intake of the control diet, but not significantly less than the 6.6% and 13.2% canola oilcake diets. The feed conversion ratio of the control diet was significantly better than the 13.2% and 20% canola oilcake diets. No significant differences were found in week six between the 6.6% full-fat canola diet and the control diet for broiler weights and feed intake. The feed conversion ratio of the broilers fed the 13.2% and 20% full-fat canola diets was significantly poorer than the control diet. The final body weights of the weaner piglets fed the control diet were significantly higher than the final body weights of weaner piglets fed the lupin containing diets. The average daily gain of the weaner piglets fed the control diet was significantly higher than the gain of the weaner piglets fed the lupin containing diets. No significant differences in the feed intake and feed conversion ratio between the different lupin inclusion levels were detected. There were no significant differences in body weight, feed intake, average daily gain and the feed conversion ratio, between the various full-fat canola containing diets and the control diet. A significant difference in body weight was found between the weaner piglets fed the 20% canola oilcake diet and the weaner piglets fed the control diet. There were no significant differences in feed intake between the various inclusion levels of canola oilcake. The control and 6.6% canola oilcake containing diets had significantly higher average daily gains than the 20% canola oilcake containing diet. In the final trial the finisher pigs fed the test diet containing 25.00% lupins, had a final body weight significantly lighter than the final body weight of the finisher pigs fed the other test diets. The finisher pigs fed the test diet containing 25.00% lupins, also had a significantly reduced average daily gain and feed intake. The feed intake of the 25.00% canola oilcake diet was significantly lees than the feed intake of the 16.75% full-fat canola containing diet. The feed conversion ratio of the 25.00% lupin containing diet was significantly poorer than the feed conversion ratio of the 16.75% lupin containing diet, 8.25% lupin containing diet, 16.75% full-fat canola containing diet, 25.00% canola oilcake containing diet and the control diet. In a choice feeding trial growing pigs were offered four diets with four different protein sources: sweet lupins (25% inclusion level), canola oilcake (25% inclusion level), full-fat canola (25% inclusion level) and soybean oilcake (25% inclusion level), while their daily intakes were recorded. In a second choice feeding trial pigs were offered ten different diets with increasing levels (6.6%, 13.2%, 20%) of either sweet lupins, canola oilcake meal or full-fat canola meal. The pigs consumed significantly more of the soybean oilcake containing diet compared to diets containing the alternative protein sources. Pigs consumed significantly less of the full-fat canola diet compared to the sweet lupin and canola oilcake diets. Ten different canola cultivars were collected from two different locations in the Mediterranean rainfall area of South Africa namely the Western Cape (Swartland) and Southern Cape (Rûens) grain producing areas. The sinapine and glucosinolate content of various canola cultivars was compared and the influence of locality on the sinapine and glucosinolate content of the canola cultivars was determined. There were no significant differences (P < 0.05) in sinapine content when the canola produced in the Western and Southern Cape were compared. Varola 54 and Rainbow cultivars had significantly higher (P < 0.05) sinapine contents compared to the Varola 50 cultivar. Samples of lupins, field peas, faba beans and narbon beans were collected and analysed for amino acids, alkaloids, non-starch polysaccharides, tannin and starch. The digestible energy value of these alternative protein sources for pigs was determined. Significant differences were found in the amino acid content of the various crops. The alkaloid content of the lupins varied significantly between the sweet and bitter lupin varieties. Sweet L. angustifolius cultivars contained ca 50mg/kg and the bitter L. angustifolius cultivars ca 15000mg/kg alkaloids. The mean alkaloid content of L. albus cultivars was ca 1300mg/kg. The faba beans, narbon beans and peas had significantly higher values for tannins and starch, compared to lupins.

Thesis (MPhil (Animal Sciences))--University of Stellenbosch, 2006. / Rickets is described as a disease that affects young growing poultry. Poorly mineralized bones with thickened and irregular growth plates characterize it. The onset of rickets is characterized by a failure of mineralization of cartilage and bone. Other symptoms of rickets include reluctance to movement in affected birds. These birds will sit on their hocks and if startled they use their wings for balance. On necropsy, bones are soft and fragile and they have thickened growth plates. In this study 30% of the chicks aged between 7 and 8 days from a broiler flock, started showing splay leg problems. Affected chicks were unable to support their weight on their legs, some showing paralysis. The bones were soft and rubbery. To try and identify the possible cause, bones from the affected chicks were analyzed for calcium (Ca) and phosphorus (P) to determine the Ca:P ratio. Blood serum was also analyzed for the mineral content. Ca and P were the main focus of the tests as the problem was suspected to be rickets. The feed was analyzed for protein, Ca and P. The bone analysis showed a Ca:P ratio of less than 2:1, while results of the blood serum showed an inverse Ca: P ratio. The analysis results of the feed as well as the bones showed an imbalance in the Ca:P ratio which according to literature and research done is a possible cause for rickets. These findings combined with the symptoms displayed by the affected birds, lead to the suggestion that the problem in this study was rickets.

Thesis (MScAgric)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Storing soil organic carbon (SOC) is a possible way of reducing atmospheric CO2 and potentially mitigating the effects of global warming. This study looks at soil carbon stocks, the sampling methodology and modelling of soil organic carbon in indigenous forests, wetlands, grasslands and pine plantations in Woodbush in the North-Eastern escarpment of Limpopo Province, South Africa. Dominant Pine species planted in Woodbush are Pinus patula, Pinus elliotti and Pinus taeda. Woodbush plantation was selected as study area because it provided easy access to all the ecosystems that were to be studied. All ecosystems in Woodbush are located in such a way that it was easy to compare them, as they existed under similar environmental and climatic conditions. The climatic conditions of Woodbush promote accumulation of SOC due to relatively higher precipitation and cooler temperatures than most parts of Limpopo Province. Five transects were made: two in indigenous forests and three in plantations. Only the surface (0-7 cm) layer was sampled with a distance of 20 m between sampling points. Transects were not made in grasslands and wetlands because of the patchy occurrence of these ecosystems. In addition to transects, eight 1ha plots, two in each ecosystem, were sampled. Surface (0- 7 cm depth) samples were collected on a grid of 20 x 20 m in each sampling plot. Two soil profile pits were sampled in each sampling plot, with samples being taken at 5, 10, 15, 20 30, 40, 50 60, 75 and 100 cm depth. The average carbon stocks per hectare of land to a soil depth of 100 cm were as follows: 71 t.ha-1 in wetlands, 28 t.ha-1 in grasslands, 64 t.ha-1in indigenous forests, and 46 t.ha-1 in pine plantations. Although wetlands sequestered large amounts of SOC per hectare, their relative contribution to carbon sequestration was low because of the relatively small area (87.2 ha) they occupy in the study area (and in South Africa). Prediction models for vertical distribution of SOC were developed using STATISTICA 6.0 for each ecosystem in order to estimate the carbon stocks to a depth of 100 cm based on SOC content and soil bulk density of the surface samples. These models were developed from observed values in soil profiles for each ecosystem. SOC content and carbon stocks were analyzed using GIS (ARCVIEW). The GIS analysis was aimed at assessing the effect of topography, elevation, soil type, and vegetation on accumulation and distribution of SOC stocks. Most shallow Inanda soils were distributed at elevations between 1545 m and 1777 m, and on a gentle slope in the Northern aspect of the mountain. Deep Inanda soils were found mostly in the lower elevation range of 967 m and 1545 m on moderate slopes. Deep and shallow Inanda soils were found on the southern aspect. Deep Kranskop soils are evenly distributed and mostly found at an elevation range of between 1080 and 1430 m on gentle slopes, while at an elevation range of between 1430 and 1780 m, they were found on moderate slopes. Deep soils had higher SOC stocks than shallow soils and soils in the southern aspects had higher SOC stocks than in the northern aspects. / AFRIKAANSE OPSOMMING: Die berging van grond organiese koolstof is ‘n moontlike manier om atmosferiese koolsuurgas (CO2) te verminder en dus om die invloed van globale verwarming te versag. In hierdie studie was die grond-koolstof voorraad bestudeer, asook die metodologie van die monsterneming en modellering van organiese grond-koolstof van inheemse woude, vleie, grasvelde en denneplantasies. Die studie was uitgevoer op Woodbush plantasie gele op die Noord-Oosterlike platorand van die Limpopo Provinsie, Suid-Afrika. Die algemeenste dennespesies in Woodbush is Pinus patula, Pinus elliotti en Pinus taeda. Die Woodbush plantasie was gekies as studiegebied omdat dit oor al die ekosisteme wat bestudeer moet word, beskik. Die ekosisteme in Woodbush is naby mekaar en dus maklik vergelykbaar want die omgewings- en klimaatstoestande is eenders. Die klimaatstoestande van Woodbush bevorder die akkumulasie van grond organiese koolstof omdat die reënval hoër en die temperature laer is as in die meeste ander dele van die Limpopo Provinsie. Vyf dwarssnitte was gemaak, twee in inheemse woude en drie in plantasies. Monsters was net uit die grondoppervlak laag geneem (7 cm) met 20 m tussen monsterpunte. Dwarssnitte was nie in grasvelde en vleie gemaak nie want hierdie sisteme is te gelokaliseerd. Monsters was ook geneem in agt 1 ha persele, twee in elke ekosisteem. Oppervlakmonsters (tot ‘n diepte van 7 cm) is op ‘n ruitnet van 20 x 20 m uit elke perseel versamel. Monsters was verder ook geneem uit twee profielgate per perseel, op dieptes 5, 10, 15, 20, 30, 40, 50, 60, 75 en 100 cm. Die gemiddelde koolstof voorraad per hektaar, op ‘n gronddiepte van 100 cm, was as volg: 71 t.ha –1 in vleie, 28 t.ha-1 in grasvelde, 64 t.ha-1 in inheemse woude en 46 t.ha-1 in denneplantasies. Alhoewel vleie groot hoeveelhede grond organiese koolstof akkumuleer, is hulle bydrae tot koolstof akkumulasie laag want hulle beslaan ‘n klein oppervlak binne die studiegebied (87.2 ha) asook klein oppervlaktes binne Suid-Afrika. Voorspellingsmodelle vir die vertikale verspreiding van grondkoolstof was met die gebruik van STATISTICA 6.0 ontwikkel ten einde te skat wat die koolstofvoorrraad op ‘n diepte van 100 cm was. Die skattings was gebaseer op organiese grondkoolstofinhoud en die gronddigtheid van oppervlakmonsters. Hierdie modelle was ontwikkel vanaf die waargenome waardes van grondprofiele vir elke ekosisteem. Die organiese koolstofinhoud van die grond en die koolstofvoorraad is ontleed met behulp van GIS (ARCVIEW). Die GIS ontleding was daarop gemik om die effek van topografie, hoogte bo seespiëel, grondtipe en plantegroei, op die akkumulasie en verspreiding van organiese grondkoolstof, te beraam. Die meeste vlak Inanda grondvorms kom voor tussen 1545 m en 1777 m bo seespiëel, asook op effens steil hellings op die Noordelike berghang. Die diep Inanda grondvorms is geleë op laer hoogtes bo seespiëel, gewoonlik tussen 967 en 1545 m, op effens steil hellings. Beide diep en vlak Inanda gronde word gevind op die suidelike berghang. Diep Kranskop gronde is eweredig versprei en word gewoonlik tussen 1080 en 1430 m bo seespiëel, op effens steil hellings, gevind. Dit kom ook voor op matig steil hellings, tussen 1430 en 1780 m bo seespiëel. Daar is meer organiese koolstof in diep grond as in vlak grond en meer in gronde teen die suidelike hang as op die noordelike hang.

Thesis (MScAgric (Soil Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Acidic soils are a major limitation to agriculture worldwide. The Highveld in South Africa has many acidic soils and several coal burning power stations. These coal burning power stations generate alkaline fly ash as a waste material and it can thus serve as an ameliorant to the surrounding acidic soils. A two year field trial was undertaken to compare fly ash and other calcium ameliorants to alleviate the effects of subsoil acidity on maize root development. The field trail was established on Beestepan Farm in Middelburg, Mpumalanga. It consisted of 24 treatments, each done in triplicate, rendering a total of 72 plots. The materials used were unweathered fly ash (CCE 10%), calcitic lime (CCE 77%) and Calmasil (a calcium silicate slag, CCE 99%). Calmasil and lime were applied at rates of 0-, 1-, 2-, and 4t/ha, while fly ash was applied at 0-, 7-, 14- and 28t/ha. These treatments were applied to an acidic sandy loam soils in the presence or absence of 4t/ha gypsum. Beans were harvested after the first season following the application of amendments and maize was harvested in the second season. Yield, root length, leaf and soil analysis was undertaken to evaluate the effectiveness of the different liming materials. The effect of the treatments on fertility indicators such as pH, exchangeable acidity, Ca and Mg was investigated. Results indicated that all liming materials increased topsoil pH, soil nutrient and base status and crop yield in both seasons. Calmasil was the superior liming material in all respects. Fly ash increased pH minimally but reduced exchangeable acidity by 12% and 24% in the first and second seasons, respectively. Fly ash increased topsoil Ca levels from 74 to 102mg/kg and subsoil Ca from 61 to 114mg/kg. Topsoil Mg levels were increased from 7.3 to 16mg/kg and subsoil Mg was increased from 9.4 to 13mg/kg. The consequence of these increased nutrients was the subsequent increased foliar uptake of Ca and Mg. The substantial increase in bean yield from 958 to 1724kg/ha and maize yield from 5569 to 7553kg/ha following ash application compared well with results obtained from lime and Calmasil application. This may partly be due to the presence of additional plant nutrients such as P and K in the fly ash. Dissolution behaviour of fly ash indicates that upon exposure to acidity the release of micronutrients like B, Co, Cu, Fe, Mo, Mn and Zn occurs, and preliminary data shows that there is comparatively little concern regarding heavy metal accumulation in crops. The application of 4t/ha gypsum had no effect on pH and decreased subsoil acidity only minimally however, subsoil Ca status and acid saturation levels were considerably improved which would possibly account for the overall beneficial effect on maize yield, increasing by an average of 1071kg/ha. It was not possible to make any conclusions relating treatment application and maize root length. This field trial has confirmed that fly ash can be used as an efficient liming material and that it compares well with traditional liming materials. / AFRIKAANSE OPSOMMING: Suurgronde is ‘n groot beperking tot landbou wêreldwyd. Die Suid Afrikaanse Hoëveld het menigte suurgronde en verskeie steenkool-aangedrewe kragstasies. Hiedie kragstasies produseer alkaliese vliegas as ‘n afvalproduk. Hierdie vliegas kan dus dien as ‘n grondverbeteringsmiddel vir die aangrensende suurgronde. ‘n Tweejarige veldproef was onderneem om vliegas met ander kalsium-bevattende grondverbetereringsmiddels te vergelyk om die effek van ondergrondse suurheid op mielies op te hef. Hierdie veldproef was opgeset te Beestepan plaas in Middelburg, Mpumalanga. Dit het bestaan uit 24 behandelings wat drie keer herhaal was en lewer dus ‘n totaal van 72 persele. Die kalkmateriale wat gebruik was, is onverweerde vliegas (KKE 10%), kalsitiese kalk (KKE 77%) en Calmasil (‘n kalsium silikaat slak, KKE 99%). Calmasil en kalk was toegedien teen 0-, 1-, 2-, en 4t/ha, en vliegas teen 0-, 7-, 14- en 28t/ha. Hierdie behandelinge was toegedien tot ‘n suur leemsand met of sonder gips. Gips was toegedien teen 4t/ha. Een jaar nadat behandelinge toegedien was, is boontjies geoes en mieles was die daaropvolgende jaar geoes. Opbrengs, wortel lengte blaar- en grondontledings was uitgevoer om effektiwiteit te evalueer. Die effek van die behandelinge op indikatore van grondvrugbaarheid soos pH, uitruilbare suurheid, Ca en Mg was ondersoek. Resultate dui daarop dat alle kalkmateriale die grond se voedingstof- en basisstatus, bogrond pH asook gewasopbreng verhoog het. Calmasil was die beste kalkmateriaal in alle opsigte. Vliegas het die pH minimaal verhoog, terwyl dit die uitruilbare suurheid verminder het met 12% en 24% in die eerste en tweede jaar onderskeidelik. Vliegas het bogrond Ca vlakke vanaf 74 tot 102mg/kg vermeer, sowel as ondergrond Ca vanaf 61 tot 114mg/kg. Bogrond Mg was vermeer vanaf 7.3 tot 16mg/kg, asook ondergrond Mg vanaf 9.4 tot 13 mg/kg. Die gevolg van hierdie verhoogde voedingstowwe was die toename van Ca en Mg in die blare van die gewasse. Die beduidende toename in opbrengste van boontjies vanaf 958 tot 1724mg/kg en mielies vanaf 5569 tot 7553kg/ha na die toediening van vliegas vergelyk goed met die resultate van kalk en Calmasil. Dit is gedeeltelik toe te skryf aan die teenwoordigheid van addisionele plantvoedingstowwe soos P en K in vliegas. Oplossingstudies van vliegas dui op die teenwoordigheid van mikrovoedingstowwe soos B, Co, Cu, Fe, Mo, Mn en Zn. Aanvanklike data wys dat daar relatief min kommer oor swaarmetaal akkumulasie in gewasse is. Alhoewel 4t/ha gips geen effek op pH gehad het nie, en ondergondrondse suurheid minimaal verminder het, het ondergrondse Ca en gevolglik suurversadiging heelwat verbeter. Dit mag moontlik as verduideliking dien vir die oorhoofse voordelige effek van gips op mielie opbrengste, wat verhoog het met ‘n gemiddelde 1071kg/ha. Oorvleuende omstandighede het daartoe gelei dat geen konkrete afleidings gemaak kon word oor die wortel lengte van die mielies nie. Hierdie veldproef bevestig dat vliegas as ‘n effektiewe kalkmateriaal gebruik kan word en goed vergelyk met tradisionele kalkmateriale.

Thesis (MScAgric (Soil Science))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: The topic of landscape heterogeneity has captured the imagination of ecologists and agriculturists alike and has been extensively investigated in this dissertation. Heuweltjies are landscape features putatively created by the termite Microhodotermes viator through their burrowing and nest-building activities. They have been closely examined in the natural veld of the Western Cape in the recent past and are the focus of many ecological studies. However, the effect of heuweltjies in cultivated landscapes (e.g. vineyards, orchards and wheat lands) remains unexplored. This study contributes significantly to our understanding of soil modifications associated with heuweltjies, as well as the physiology of vines growing on and off heuweltjies and wine made from these vines. It was hypothesized that heuweltjies occurring in cultivated areas can significantly affect crop yield and quality, thereby establishing itself as a potentially important role player in the agricultural economy of the Western Cape. This study was conducted in two climatic regions of the Western Cape, Stellenbosch (Mediterranean climate, Cabernet Sauvignon) and Robertson (semi-arid climate, Shiraz) to better understand how differences in heuweltjie characteristics correspond to differences in rainfall and temperature. In both study areas, heuweltjie soils were compared to non-heuweltjie soils with respect to physical and chemical. Grapevines associated with these heuweltjies were also compared to those growing on the adjacent, non-heuweltjie soils to determine any variation in vine vigour, physiology, phenology, berry characteristics and wine quality. Through the use of ANOVA's and Fisher's LSD posthoc tests to indicate statistical significance in soil and grapevine characteristics, it was apparent that heuweltjies induce substantial changes in soil and vine properties. Significant differences in the water content exist between the soils of the heuweltjies and non-heuweltjie areas. Heuweltjie soils exhibited higher values in comparison to the non-heuweltjie soils in the Stellenbosch study area, with opposite results in Robertson. Heuweltjie soils also displayed higher exchangeable calcium and magnesium and higher total carbon and total nitrogen values than non-heuweltjie soils in both study areas. Differences in physiology were more subtle, but vine vigour was severely altered on the heuweltjie-associated vines, exhibiting excessive vegetative growth in Stellenbosch, leading to variations in berry characteristics on and off the heuweltjies. Again, the opposite was observed for Robertson. Lower sugar and alcohol percentages and higher titratable as well as malic acid concentrations were observed in the wines emanating from the heuweltjies in Stellenbosch. Sensory analyses proved significant, as lower astringency and alcohol burn were detected in the Cabernet Sauvignon heuweltjie wines than the non-heuweltjie wines in the Stellenbosch study area. Chemical differences in the wines from the Robertson study are were insignificant. However, a significantly lower fruitiness was observed in the Shiraz heuweltjie-wines when compared to the non-heuweltjie wines. Differences in soil water content between heuweltjies and its adjacent soils was the most influential factor in this study, and affected all of the soil-grapevine interactions to a large extent. Further research need to be conducted to better understand and clarify the reasons behind these variations, as well as possible effects of global warming on heuweltjie functioning in different climatic regions of the Western Cape. / AFRIKAANSE OPSOMMING: Die onderwerp van landskap heterogeniteit het die verbeelding van beide ekoloë en landboukundiges aangegryp en is op `n omvangryke wyse ondersoek in hierdie tesis. Heuweltjies is landskap eienskappe geskep deur die uitgrawe en nesbou aktiwiteite van die termiet Microhodotermes viator. Heuweltjies in die natuurlike veld is intensief bestudeer in die onlangse verlede en is die fokus van `n verskeidenheid ekologiese studies. In bewerkte landskappe (bv. wingerde, vrugteboorde en koringlande) is daar egter `n groot tekort aan navorsing oor die invloed van heuweltjies. Hierdie studie dra grotendeels by tot ons begrip van heuweltjie-geassosieërde grondverandering, asook die fisiologie van wingerd wat groei op en af van heuweltjies, sowel as die wyn afkomstig van hierdie wingerdstokke. Hipoteties sal heuweltjies in bewerkte areas die gewasopbrengs asook –kwaliteit betekenisvol beïnvloed en word so dus gevestig as `n potensieël belangrike rolspeler in die landbou-ekonomie van die Wes-Kaap. Die studie was onderneem in twee klimaatstreke van die Wes-Kaap, Stellenbosch (Mediterreënse klimaat, Cabernet Sauvignon) en Robertson (semi-ariede klimaat, Shiraz) om vas te stel hoe verskille in heuweltjie eienskappe ooreenstem met verksille in reënval en temperatuur. In beide studie areas is heuweltjie gronde met nie-heuweltjie gronde vergelyk met betrekking tot fisiese en chemiese eienskappe. Wingerdstokke geassosieër met heuweltjies is ook vergelyk met dié wat heuweltjies omring om enige variasie in groeikrag, fisiologie, fenologie, druifkorrel eienskappe en wynkwaliteit te bepaal. Deur gebruik te maak van ANOVA's en Fisher se LSD posthoc toetse om statistiese betekenisvolheid in grond- en wingerdeienskappe aan te dui, was dit duidelik dat heuweltjies wesenlike veranderinge in dié eienskappe teweegbring. Betekenisvolle verskille heers in die waterinhoud tussen die heuweltjie en nie-heuweltjie gronde. Heuweltjie gronde het hoër waardes getoon in vergelyking met die nie-heuweltjie gronde in die Stellenbosch studie area, met teenoorgestelde bevindings in Robertson. Heuweltjie gronde het ook `n hoër konsentrasie uitruilbare kalsium en magenesium, en totale koolstof en stikstof in vergelyking met nie-heuweltjie gronde. Verskille in fisiologie was baie meer subtiel, maar wingerd groeikrag was beduidend verskillend op die heuweltjie-geasossieërde wingerdstokke, met oormatige vegetatiewe groei in Stellenbosch wat lei tot `n verskil in druifkorrel eienskappe op en af van die heuweltjie. Weereens is die teenoorgestelde waargeneem in Robertson. Laer suiker en alkohol persentasies, asook hoër titreerbare - en appelsuur konsentrasies was te bespeur in die wyne afkomstig van die heuweltjies in Stellenbosch. Sensoriese analise het betekenisvolle verskille bewys, met `n laer vrankheid en alkohol-brand sensasie waargeneem vir die Cabernet Sauvignon heuweltjie wyne as die nie-heuweltjie wyne in die Stellenbosch studie area. Chemiese verskille in die wyne vanaf Robertson was onbeduidend. Sensoriese analise het egter anders bewys, met `n betekenisvolle laer vrugtigheid te bespeur in die nie-heuweltjie wyne as die heuweltjie wyne in die Robertson studie area. Verskille in die grondwaterinhoud tussen heuweltjies en omringende gronde was die mees invloedryke faktor in hierdie studie en beïnvloed tot `n groot mate al die grond-wingerdstok interaksies. Verdere navorsing is nodig om helderheid te verskaf agter die redes vir hierdie variasies, sowel as moontlike gevolge van aardverwarming op funksionering van heuweltjies in verskillende klimaatstreke van die Wes-Kaap.