Thesis (Ph.D.)--University of Western Australia, 2007.

Thesis (MScAgric)--University of Stellenbosch, 1955. / No Abstract Available

Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The cultivation of table grapes in the warmer areas of South Africa, indeed worldwide, is complicated by rest breaking problems in spring due to delayed budbreak. In order to overcome these problems rest breaking agents, mainly hydrogen cyanamide, are applied. However, instead of alleviating the problem, additional problems such as uneven budbreak and reduced production are often induced. This study was initiated to further understand the physiological processes occurring during budbreak and how the application of hydrogen cyanamide influences these processes. The following aspects were investigated in this study: a. The effect of hydrogen cyanamide on tissue cytokinin (specifically zeatin riboside) levels of Sultanina table grape vines after application at different times before natural budbreak was studied over two seasons. In 1997, hydrogen cyanamide was applied at three weeks before induced budbreak and in 1998 at six weeks before induced budbreak. One year-old canes were sampled weekly after hydrogen cyanamide application, divided into distal and proximal sections, then further divided into buds, bark and wood tissues and the zeatin riboside (ZR) levels determined. A relatively high amount of chilling coupled to late hydrogen cyanamide application in 1997 led to a large effect on ZR release, but did not lead to significant shifting of the budbreak pattern. Zeatin riboside peaks were observed in buds, internode wood and bark of treated vines compared to control vines. The peaks were higher in distal portions compared to proximal portions in all tissues. The relatively lower chilling and earlier application of hydrogen cyanamide in 1998 had a larger effect on the budbreak pattern while the bud ZR peak was shifted earlier. The distal portion bud ZR . peak was again higher than the proximal portion bud ZR peak. In 1997, as sampling was not initiated early enough, bud ZR peaks were only observed after budbreak, while in 1998 bud ZR peaks were observed before and after budbreak. The effect of these ZR increases on the development of inflorescence primordia, subsequent bunch development and ultimately production, are discussed. b. Free xylem sap was sampled at cane and spur pruned lengths from unpruned canes of Sultanina from budswell until after budbreak in 1999 and from three table grape cultivars, i.e Sultanina, Alphonse Lavalleé and Sunred Seedless, in 2001 and ZR levels determined. The ZR levels in the buds of these three table grape cultivars, pruned to different cane lengths were also determined. One year old canes of these cultivars, were each pruned to long canes (14 buds) and short spurs (2 buds). The ZR content in buds of these canes at distal and proximal positions were determined weekly from budswell until after budbreak in 1999. Xylary ZR peaks occurred before 50% budbreak. Spur xylary ZR levels of all three cultivars followed a similar pattern, although at lower ZR levels than that of the canes. This is similar to previous studies on xylary ZR levels of apple shoots. The high levels of free ZR found in xylem sap at the distal portions of canes support the hypothesis of a cumulative ZR build-up effect as cane length increases. Spur pruning resulted in earlier budbreak and a higher final budbreak than cane pruning. The proximal portions of shoots, whether spur pruned or the proximal portions of canes, showed elevated ZR levels in all cultivars. This difference in ZR levels in bud tissue of different portions of the cane would suggest a difference in ZR consumption or turnover. The results of this study have important management implications for the cultivation of vines in warmer areas in which hydrogen cyanamide is used to alleviate budbreak problems. / AFRIKAANSE OPSOMMING: Die verbouing van tafeldruiwe in die warmer gebiede van Suid-Afrika, soos straks wêreldwyd, word bemoeilik deur rusbreekprobleme in die lente weens vertraagde bot. Rusbreekmiddels, meestal waterstofsiaanamied, word gevolglik toegedien om hierdie probleme te probeer oorkom. In plaas van opheffing van die probleem, veroorsaak hierdie toedienings somtyds addisionele probleme soos ongelyke bot en verlaagde produksie. Hierdie studie is aangepak om die fisiologiese prosesse wat tydens bot plaasvind, beter te verstaan, asook hoe die toediening van waterstofsiaanamied hierdie prosesse beïnvloed. Die volgende is in hierdie studie ondersoek: a. Die invloed van waterstofsiaanamied op lootweefsel sitokinien (naamlik zeatin ribosied, ZR) vlakke van 'n Sultanina tafeldruif wingerd is oor twee seisoene ondersoek na toediening op verskillende tye voor bot. Waterstofsiaanamied is in 1997 drie weke en in 1998 ses weke voor geïnduseerde bot toegedien. Een jaar oue lote is weekliks gemonster na waterstofsiaanamied toediening, verdeel in apikale en basale gedeeltes en verder verdeel in ogies, bas en houtweefsel en die ZR vlakke bepaal. Relatief hoër vlakke koue, gekoppel met later watersiaanamied toediening het in 1997 tot 'n groot effek op ZR vlakke gelei, maar het nie die botpatroon wesentlik verskuif nie. Zeatin ribosied pieke is waargeneem in ogies, internode hout en bas van behandelde wingerd in vergelyking met kontrole wingerd. Die pieke was hoër in apikale gedeeltes in vergelyking met basale gedeeltes in alle weefsels. Die relatief laer koue en vroeër toediening van waterstofsiaanamied in 1998 het 'n groter effek op die botpatroon gehad, terwyl die ogie ZR piek vroeër geskuif is. Die apikale gedeelte se ogie ZR piek was weereens hoër as die basale gedeelte se ogie ZR piek. Monstering was nie vroeg genoeg begin in 1997 nie, aangesien ogie ZR pieke slegs na bot waargeneem is, terwylogie ZR pieke in 1998 voor en na bot waargeneem is. Die effek van hierdie verhoging in ZR vlakke op die ontwikkeling van blom primordia, daaropvolgende tros ontwikkeling en uiteindelik produksie, is bespreek. b. Vry xileemsap is gemonster van langdraer en kortdraer gedeeltes van ongesnoeide lote van Sultanina vanaf ogieswel tot na bot in 1999 en vanaf drie tafeldruif kultivars, naamlik Sultanina, Alphonse lavalleé en Sunred Seedless, in 2001 en die ZR vlakke bepaal. Die ZR vlakke van ogies van hierdie drie kultivars, gesnoei tot verskillende lootlengtes is ook bepaal. Eenjarige lote van hierdie kultivars is gesnoei tot langdraers (14 ogies) en kortdraers (2 ogies). Die ZR vlakke in ogies geleë op apikale en basale gedeeltes van hierdie lote is weekliks in 1999 bepaal vanaf ogieswel tot na bot Xileemsap ZR pieke is waargeneem voor 50% bot. Kortdraer xileemsap ZR vlakke het 'n soortgelyke patroon as die langdraers gevolg vir al drie kultivars, alhoewel teen laer ZR vlakke as die langdraers. Hierdie waarneming is soortgelyk aan vorige studies op xileemsap ZR vlakke van appel lote. Die hoë ZR vlakke gevind in die xileemsap van die apikale gedeeltes van lote ondersteun die hipotese van 'n kumulatiewe opbou van ZR soos die lengte van die loot toeneem. Die snoei van lote as kortdraers het gelei tot vroeër bot en 'n hoër finale bot persentasie as die snoei van langdraers. Die basale gedeeltes van lote het verhoogde ZR vlakke in al drie kultivars getoon, onafhanklik van die feit dat dit vanaf die kortdraer of die basale gedeelte van 'n langdraer was. Hierdie verskil in ZR vlakke in ogie weefsel van verskillende gedeeltes van die loot impliseer 'n verskil in ZR verbruik of omset. The resultate van hierdie studie het belangrike bestuursimplikasies vir die verbouing van wingerd in warmer gebiede, waar waterstofsiaanamied gebruik word om botprobleme te oorkom.

This study of the institutionalization and professionalization of agricultural chemistry during the second half of the nineteenth century analyses the relationship between chemical theories and social issues, ideas and experience of recycling, the development of fertilizers, and industrialization of agriculture. The study mainly takes a history of science and environmental history perspective with focus on the Swedish case. It does, however, address the international context offering a historical perspective of issues such as the relationship between population and natural resources, the sustainability of society and connections between science, technology and nature. The center of this study consists of an analysis of the work of the following agricultural chemists employed by the Swedish Royal Agricultural Society, enumerated in chronological order: Alexander Müller, Carl Erik Bergstrand, and Lars Fredrik Nilson. Other actors, such as agriculturists, administrators and politicians, were also important in the formation of agricultural chemistry in Sweden. Changes of aims and agricultural chemical ideals during the period of study reflect changes in society and shifting ideologies. During the second half of the nineteenth century a national "agricultural scientific infrastructure" was erected with experimental stations, agricultural schools, local experimental fields and agrarian experts. This network constituted a basis for agricultural science in society and functioned as an important channel for the modernization of agriculture and society. With agricultural chemistry as an empirical point of departure, this thesis also analyzes the transformations of agriculture with the establishment of cultural, economical and physical links between agriculture and the surrounding world. Theories about chemical cycles promoted recycling of nutrition and other materials between the city and the countryside, thereby connecting agriculture to the city. The development of new mineral and nitrogenous fertilizers gradually involved an increased use of inorganic raw materials and energy to manufacture nutrition. This process resulted in the intertwining of agriculture, science, mining, industry and energy production and the creation of an agro- industrial network, which was crucial for the development of agriculture during the twentieth century. In this context, agricultural science legitimized the development toward resource intensive farming methods. / digitalisering@umu

The archaeological and technical questions about ancient stone tools lead to various research activities such as chemical and petrographical analysis. Considering research areas and publications it can be suggested that mineralogical studies of stone samples of ancient stone tools have disclosed useful information concerning identification of the stone. Within this context, aim of this study is to determine the chemical, mineralogical and petrographical identities of the stone samples of Karain Cave (Antalya). Most paleolithic caves show one specific time interval layer but Karain Cave shows lower-upper and middle layers which give information about the migration ways between Near East and Europe. Stone tools excavated from Karain Cave are not only first human remainings in Anatolia but also first artworks of Anatolian people.Most of the stone tools excavated from Karain Cave are cherts. These cherts were analysed for archeological aspects but mineralogical, petrographical, and chemical contents have not been analysed yet. During the excavations at the Karain Cave in Antalya many stone pieces in different sizes and colors had been found. In this study ten samples were examined. The methods used consists of thin section, X- ray powder diffraction , scanning - electron microscopy coupled with energy dispersive X-ray analysis , differential thermal analyses and inductively coupled plasma mass spectrometry to determine material characteristics of the samples. Petrographically the nine of the samples are chert with some including radiolarian fossils. Microcrystalline &aacute / - quartz is the major mineral in the chert. Only one sample is composed calcite and is identified as micritic limestone. Chemical analysis reflect the typical composition of chert with the average values of / 40.9% Si and 1 sample is limestone, which is composed of 35.7% Ca . Minor elements are Fe, Al, K, and Ti in the samples. Thermal analysis is also supported the thin section studies.Further research is suggested for provenance analysis of stone tools from the Karain Cave.

MSc (Chemistry) / Department of Chemistry / In this work, modern pre-concentration techniques, namely dispersive liquid-liquid micro-extraction (DLLME) and QuEChERS, were used to analyse pesticides and heavy metals in complex matrices. The work is divided into six papers. In Papers 1, the recent developments and applications of DLLME during analysis of pesticides in food matrices were reviewed. The DLLME technique has captured the interests of many researchers in recent years. The major advantage, among others, of DLLME is miniaturisation in which the acceptor-to-donor ratio is reduced tremendously leading to high enrichment compared to other sample preparation techniques. In the present work, the different complex matrices where the DLLME technique has been employed for the analysis of pesticides are reviewed as well as the challenges associated with this technique. Papers II reviewed the recent applications and developments of the QuEChERS technique during the analysis of pesticides in food matrices. QuEChERS is a versatile pre-concentration method whose application spans the whole breath of organic compounds. There are three common standard methods used during QuEChERS and these are the original QuEChERS, AOAC and the EN methods. In this paper, recent developments and applications of QuEChERS techniques in the analysis of pesticides in food samples were reviewed. In Paper III, green pre-concentration techniques employed during analysis of pesticides were reviewed. Recently, the parameter of “greenness” during sample pre-concentration of pesticides in food matrices is as important as selectivity in order to avoid using large amounts of harmful organic solvents during sample preparation. Developing new green pre-concentration techniques is one of the key subjects in green chemistry in order to minimize the release of large volume of toxic organic solvents into the environment. Thus, to reduce the impact on the environment during trace analysis of pesticides in food matrices, new developments in pesticide pre-concentration have gone in three separate directions (which are reviewed in this paper): one is the search for more environmentally friendly solvents, the second one is miniaturization and the third one is the development of solvent-free pre-concentration techniques. Eco-friendly solvents such as supercritical fluids, ionic liquids and natural deep eutectic solvents have been developed for use as extraction solvents during pre-concentration of pesticides in food matrices. Also miniaturized pre-concentration techniques such as QuEChERS, dispersive liquid-liquid micro-extraction and hollow-fibre liquid phase micro-extraction have been used during trace analysis of pesticides in food samples as well as solvent-free techniques such as solid phase micro-extraction and stir bar sorptive extraction. All these developments are geared to ensure that pesticide pre-concentration in food matrices is green and were reviewed in this paper. The effect of vehicular emissions on the concentrations of selected heavy metals was investigated in Paper IV. The samples were pre-concentrated using DLLME prior to analysis with flame atomic absorption spectroscopy. Dithizone, chloroform and methanol were used as chelating agent, extraction solvent and dispersion solvent respectively during the DLLME technique. The pH of the sample was adjusted to around 8 using sulphuric acid or sodium hydroxide solution. The influential DLLME parameters, such as pH volume and type of extraction solvent, and voume of disperser solvent, were optimized prior to the application of the developed method to real samples (roadside dust, fruits and vegetables). In Paper V, chromium speciation in fruits and vegetables was studied. The chromium in fruit and vegetable sample juices was pre-concentrated using DLLME prior to analysis with flame atomic absorption spectroscopy. Diphenylcarbazide (DPC) was used as a chelating agent in this study, and salting out of the complex from the aqueous medium into the organic phase was effected using sodium acetate. Chloroform and methanol were used as extraction and dispersion solvents respectively in the DLLME method for the determination of chromium (VI). For total chromium, the trivalent chromium was oxidised using acidified KMnO4 to hexavalent chromium before performing the DLLME technique. The concentration of chromium (III) was determined by finding the difference between total chromium and concentration of chromium (VI). The important parameters that influence the efficiency of the DLLME technique were also optimized using the univariate approach. After optimization, the developed method was applied to real samples. In Paper VI, the concentration of malathion pesticide in fruits was determined using QuECHERS for pre-concentration and UV-Vis spectrophotometry for instrumental analysis. Acetonitrile was used as the extraction solvent and Z-sep+/PSA sorbent combination was used for sample clean-up. The acetonitrile extract from QuEChERS was then hydrolysed using KOH followed by reaction with acidified potassium bromate for colour development. The coloured product formed was then analysed using UV-Vis spectrophotometry. Among the fruits analysed, Oranges had no malathion residue in them. However, trace amounts of malathion, below WHO maximum allowable limits, were found in pears and apples. / NRF

Aflatoxin M1 (AFM1) is frequently found in milk and dairy products. It is a metabolite formed in cows from aflatoxin B1 (AFB1), contained in animal feeds. In cheese production AFM1 distributes between curds and whey. In this study, cows were fed 64 µg/AFB1/d for the high treatment, and 5 µg/AFB1/d for the low treatment, to obtain milk contaminated with AFM1 over the 0.5 µg/L and under 0.05 µg/L restrictions, respectively. Cheese was manufactured with milk contaminated with AFM1 at 0.8 and 0.03 ìg/kg by the higher and lower treatment, respectively. Two commercial cheeses were elaborated: a hard-aged cheese (cheddar cheese) and soft high moisture cheese (fresco cheese) to evaluate whether the cheese type had any impact on AFM1 analysis. AFM1 was extracted from cheese using immunoaffinity columns. Analyses were carried out by using high pressure liquid chromatography (HPLC) as the reference method and fluorometry as a method of validation. Analysis was by 2-way fixed factor analyses. AFM1 was detected in all samples by both methods of analysis. There were no detectable statistical differences between cheese types (P>0.05). AFM1 content was significantly different between the high and low concentration of AFB1 used to make the cheese type (P<0.01). Our regression model shows a linear relationship between fluorometry and HPLC methods; R2 = 0.9141 from cheddar cheese and R2 = 0.9141 from fresco cheese. There were no statistical differences between methods of analysis (P>0.05). Carryover of AFM1 in cheese detected by fluorometry in cheddar cheese was 163% and 80% for high and low treatments, respectively, and in fresco cheese was 119 and 133 for high and low treatments, respectively. These carryovers are below that reported in the literature. Results suggest that fluorometry is a simple and reliable AFM1 detection method for screening samples of complex matrices such as cheese.

This dissertation is an analysis of systematic studies of the land in the early American Republic, from the 1790s to the 1840s; more specifically, it explores the role scientific and technical practices played within that era's improvement ethic. I argue that science, as seen through the lens of agricultural chemistry and, to a lesser extent, geology, became an important, acceptable, and credible way to interact with early Republic land because it fit within the multivalent improvement ethic of that period. Through a study of the agricultural press, farmers’ diaries, and county and statewide scientific surveys, I examine how scientific and technical practices aided agricultural improvement, how they were promoted or resisted by local farmers, and in what ways they gained social credibility for interpreting and interacting with agrarian nature. Part I, “The Place of Science,” explores how science was interpreted by people. I there ask about the social, moral, instrumental, and literary places of agricultural science in rural culture. Part II, “The Science of Place,” asks instead how science interpreted the land, there studying county and state scientific surveys in Virginia. Underlying the entire work is an exposition of the georgic ethic (as distinct from the pastoral ethic), which emphasizes the labor-based means through which most rural peoples understood their land and ties the moral plea for cultural improvement to the material pursuit of agricultural progress. The story herein introduces the production of an important set of conditions that allowed later scientific developments across the land to have meaning and significance: forms of communication, precedents of organization, field-tested modes of analysis, a tradition of improvement and experimentation, the long-standing search for solutions to soil exhaustion, increasingly mechanistic philosophies of soil composition, a market force to drive all of these, and a unique American political and agricultural environment into which the above could take shape. The lesson is not that the entirety of our modern scientific worldview can be traced to the activities of a disgruntled antebellum American farming class, but that this example of rural science and agricultural improvement provides a fruitful example of what it takes to make a scientific worldview. Thus, arguments about philosophical and conceptual bases for scientizing the land–topics of great importance in the fields of environmental history and various branches of science and technology studies–gain strength and plausibility by reference to the workings of antebellum agents who first argued over the value of using science to define their land. By putting the circulation of agricultural science in the context of early Republic improvement-minded agents, we can better locate agrarian American culture into a post-Enlightenment setting, we are better equipped to recognize how everyday citizens came to treat scientific practices as legitimate means of interacting with their lands, and we have a more developed picture of how morality, materiality, and theory were wedded in the much-revered principles of practice and practicality. The sum of those points highlights how traditional means of managing the land, as with religious doctrine, almanac strictures, the lessons inherited through family lineage by generations of daily practice, or uncodified folk knowledge in general, were being complemented with or displaced by organized, methodical, and systematic–eventually, scientific–practices on the land. / Ph. D.

Made available in DSpace on 2016-04-28T14:16:10Z (GMT). No. of bitstreams: 1 Alexandre Alves de Araujo Costa.pdf: 541744 bytes, checksum: 43f4ea52683ab71fcf18f7280822265d (MD5) Previous issue date: 2010-10-20 / The agriculture, activity of primal importance for the human being, it is indeed a route of access for the application of the chemical knowledge towards its practice. Besides that, a sort of theoric concern that also configurated itself as one of the outlines on which was delineated the agricultural practices at the end of XVIII century and beginning of the XIX century, aiming the thecnincal development. Humphry Davy, who during his his career developed several studies with latent practical concerns, starts in 1802 one cycle of lectures about agricultural chemistry, supported by the Board of Agriculture, which extended until 1812, culminating with the publication of the book Elements of Agriculture in 1813. Davy, is usually known by his works with eletriciy and the posterior identification of several chemical elements. In his researchs, showed great interest towards nature and the composition of the matter, what was not different on agricultural researchs. Under the light of current historiography of science, this work intends to analyze how Humphry Davy used to explain the phenomena linked to vegetation, besides of the relevance of his books to agricultural practices / A agricultura, atividade de fundamental importância para o ser humano, é uma via de acesso à aplicação do conhecimento químico à prática. Além disso, uma certa preocupação teórica também se configurou como um dos contornos em que se delineava a prática agrícola do final do século XVIII e início do século XIX, com vistas ao melhoramento técnico. Humphry Davy, que durante sua carreira desenvolveu vários estudos com latente preocupação prática, inicia em 1802 um ciclo de palestras sobre química agrícola, apoiadas pelo Board of Agriculture, que se estenderam até 1812, culminando com a publicação do livro Elements of Agriculture em 1813. Davy é normalmente conhecido por seus trabalhos envolvendo eletricidade e a posterior identificação de vários elementos químicos. Em suas pesquisas, manifestava grande interesse em relação à natureza e à composição da matéria, o que não se mostrou diferente nas pesquisas agrícolas. À luz da atual historiografia da ciência, este trabalho pretende analisar como Humphry Davy explicava os fenômenos ligados à vegetação, além da relevância do seu livro às práticas agrícolas

[Truncated abstract] The principal aim of this thesis was to examine the response of the microbial community to the addition of small amounts (<50 μg C g-1 soil) of organic C substrates (‘trigger molecules’) to soil. This addition is comparative to indigenous soluble C concentrations for a range of soil types in Western Australia (typically measured between 20 and 55 μg C g-1 soil). Previously it has been reported that the application of trigger molecules to European soils has caused more CO2-C to be evolved (up to six fold) than was applied . . . Findings from this study indicated that there was an additional CO2 release (i.e. greater than the C added) on application of organic C substrates to some soil treatments. However, findings from this study indicate that the response of the microbial community to small additions of soluble C substrate is not consistent for all soil types and may vary due to greater availability of C, and supports the premise that microbial responses vary in a yet to be predicted manner between soil type and ecosystems. Differences in microbial response to the addition of soluble organic C are likely attributable to differences in soil attributes and environmental factors influencing both the diversity of microbes present and the frequency of food events. Theoretically, trigger molecules could also provide a possible control mechanism for microorganisms in arable farming systems. These mechanisms include stimulating either targeted pathogenic microorganisms that starve after depletion of a suitable substrate; or stimulating beneficial microorganisms to manipulate nutrient cycling, by targeting specific functional groups and altering mineralisation and immobilisation turnover rates.