Since grass is abundant on our planet it plays an important role in the rendering of many different outdoor scenes. This study focuses on the real-time rendering of many individual grass blades with geometry. As a grass blade in real life is very thin and have a simple shape it can be represented with only a handful of vertices. The challenge is introduced when a meadow of grass is to be rendered as it can contain billions of grass blades. Two different algorithms were developed; one which use traditional vertex buffers to store and render the grass blades while the other makes use of textures. Quantitative data was generated from these algorithms. Among this data were images of the scene. These images were subjected to a questionnaire to collect qualitative information about the grass. All the generated data was then analyzed and interpreted to find advantages and disadvantages of the algorithms. The buffer-based algorithm was found to be slightly more computationally efficient compared to the texture-based algorithm. The quality of the visual result was perceived to be towards good while the realism was perceived as mediocre at best. The advantage of the texture-based algorithm is that it allows more options to handle the grass blades data when rendering. Using the terrain data to generate the grass blades was concluded to be advantageous. The realism of the grass could have been improved by using a grass blade texture as well as introducing variety in density and grass species. / Eftersom gräs är rikligt på vår planet spelar den en viktig roll vid renderingen av många olika utomhusscener. Denna studie fokuserar på realtidsrendering av många individuella gräsblad med geometri. Eftersom ett gräsblad i verkligheten är mycket tunnt och har en enkel form kan den representeras med endast en handfull vertiser. Utmaningen introduceras när en äng av gräs ska renderas eftersom som den kan innehålla miljarder gräsblad. Två olika algoritmer utvecklades, en som använder traditionella vertex buffrar för att lagra och rendera gräsbladen medan den andra använder sig av texturer. Kvantitativ data genererades från dessa algoritmer. Bland denna data fanns bilder av scenen. Dessa bilder utsattes för ett frågeformulär för att samla in kvalitativ information om gräset. All den data som genereras analyserades och tolkades för att hitta fördelar och nackdelar med algoritmerna. Den bufferbaserade algoritmen upptäcktes vara beräkningsmässigt effektivare jämfört med den texturbaserade algoritmen. Den upplevda kvalitén på det visuella resultatet ansågs vara närmare bra medan realismen uppfattades som medioker i bästa fall. Fördelen med den texturen-baserad algoritm är att den tillåter fler möjligheter att hantera gräsblads-data vid rendering. Slutsatsen av att använda terrängens data för att generera gräsbladen sågs vara fördelaktigt. Realismen av gräset kunde förbättrats genom att använda en gräsblads-textur, samt variation i densitet och gräsarter.

Low-grade coal, a poor source of energy, has long been regarded as waste material by the coal mining industry. Biological degradation of this coal material by ligninolytic fungal strains presents a viable strategy towards eliminating this unusable fossil fuel. To this end, a novel and patented bioprocess termed Fungcoal was developed. Fungcoal is a biological process utilised in the in situ treatment of waste coal and is based on the mutualistic relationship between the fungus Neosartorya fischeri and the graminaceous species Cynodon dactylon. The process facilitates the rapid conversion of waste coal into soil-like material that stimulates establishment of vegetation for eventual coal dump rehabilitation. While a number of in vitro studies have identified various fungal strains as efficient coal degraders, the mechanisms involved in the Fungcoal-stimulated degradation process have not been fully elucidated. Furthermore, implementation of Fungcoal at both pilot and commercial scale has not been achieved. Thus the objective of this work was to investigate Fungcoal as a bioprocess via examining the role of coal degrading fungi (CDF) and grasses as biocatalysts in coal biodegradation and for the self-cladding of waste coal dumps. Initially, waste coal degradation by N. fischeri, strain ECCN 84, was investigated, specifically focusing on the mechanisms underpinning the process. In vitro studies showed the addition of waste coal induced active fungal colonisation resulting in increased fungal biomass. Increased extracellular laccase (LAC) activity, occuring concomitantly with an increase in hyphal peroxisome proliferation, was also observed in the coal supplied fungal cultures. Analysis of the colonised waste coal revealed a time dependent reduction in the percentage weight of elemental carbon coupled with an increase in elemental oxygen. The results supported metabolism and degradation of waste coal by N. fischeri strain ECCN 84 and involvement of fungal extracellular laccase. The contribution of C. dactylon, a C4 grass species to in situ biodegradation of waste coal in the presence of coal degrading and mycorrhizal fungi (MF) was also investigated. Enhanced degradation of the waste coal into a humic soil-like material was observed within the rhizosphere. Analysis of the resultant substrate revealed an increased concentration of highly oxidised humic-like substances (HS). Fungi remained viable in the rhizosphere up to 47 weeks post-inoculation and cultivation of C. dactylon, indicating the resultant humic substance-rich rhizosphere provided an environment conducive for microbial proliferation and activity. Furthermore, humic substance enrichment of waste coal substrates supported germination and seedling emergence of several agronomic species including Zea mays (corn), Phaseolus vulgaris (bean), Pisum sativum (pea), and Spinacia oleracea (spinach). Use of various cladding materials to support coal biodegradation, by fungus-grass mutualism and rehabilitation of waste dumps was evaluated at commercial scale. While substantial physico-chemical changes were not evident in the absence of cladding or where waste coal was used as cladding material, successful establishment of grass cover and diversity was achieved within three hydrological cycles on dumps cladded with weathered coal. Work presented in this thesis successfully demonstrates the degradation of waste coal by N. fischeri. The biodegradation process included enhanced extracellular LAC activity coupled with increased 3 waste coal oxidation. Increased HS concentration of waste coal substrate supported germination and early seedling establishment of several agronomic species. At commercial scale a co-substrate in the form of carbon-rich weathered coal was essential to support fungus-grass mutualism and Fungcoal-induced rehabilitation. These findings support the developed Fungcoal concept and the underpinning rationale that the phyto-biodegradation of waste coal indeed depends on the mutualistic interactions between grass root exudates and the ligninolytic and mycorrhizal fungi. Taken together, these findings provide practical evidence of the contribution of fungi and grasses as mutualists in the biodegradation of waste coal and sustainable rehabilitation of waste coal dumps

Fundamental processes involved in the microbial degradation of coal and its derivatives have been well investigated and documented over the past two decades. However, limited progress in industrial application has been identified as bottleneck in further active development of the field. The sporadic and unanticipated growth of Cynodon dactylon (Bermuda grass) has been observed on the surface of some coal dumps in the Witbank coal mining area of South Africa. Preliminary investigations showed the formation of a humic soil-like material from the breakdown of hard coal in the root zone of these plants. The potential of this system to contribute to industrial scale bioprocessing of hard coal was investigated. This study involved an investigation of the C. dactylon/coal rhizosphere environment and demonstrated the presence of fungal species with known coal bioconversion capability. Amongst these Neosartorya fischeri was identified and its activity in coal bioconversion was described for the first time. Cynodon dactylon plant roots were also shown to be colonized by mycorrhizal fungi including Glomus, Paraglomus and Gigaspora species. The role of plant photosynthate translocation into the root zone, providing organic carbon supplementation of fungal coal bioconversion was investigated in deep liquid culture with the N. fischeri isolate used as the biocatalyst. Organic acids, sugars and complex organic carbon sources were investigated and it was shown that glutamate provided significant enhancement of bioconversion activity in this system. The performance of N. fischeri in coal bioconversion was compared with Phanaerochaete chrysosporium and Trametes versicolor, both previously described fungal species in the coal bioconversion application. Fourier transform infrared spectroscopy indicated more pronounced oxidation and introduction of nitro groups in the matrix of the humic acid product of coal bioconversion in N. fischeri and P. chrysosporium than for T. versicolor. Macro-elemental analysis of biomass-bound humic acid obtained from the N. fischeri catalyzed reaction showed an increase in the oxygen and nitrogen components and coupled with a reduction in carbon and hydrogen. Pyrolysis gas chromatography mass spectroscopy further supported the proposal that the mechanism of bioconversion involves oxygen and nitrogen insertion into the coal structure. The C. dactylon bituminous hard coal dump environment was simulated in a fixed-bed perfusion column bioreactor in which the contribution of organic supplement by the plant/mycorrhizal component of the system was investigated. The results enabled the proposal of a descriptive model accounting for the performance of the system in which the plant/mycorrhizal component introduces organic substances into the root zone. The non-mycorrhizal fungi utilize the organic carbon supplement in its attack on the coal substrate, breaking it down, and releasing plant nutrients and a soil-like substrate which in turn enables the growth of C. dactylon in this hostile environment. Based on these results, the Stacked Heap Coal Bioreactor concept was developed as a large-scale industrial bioprocess application based on heap-leach mineral processing technology. Field studies have confirmed that bituminous hard coal can be converted to a humic acid rich substrate in a stacked heap system inoculated with mycorrhizal and N. fischeri cultures and planted with C. dactylon.

A vegetation survey, based on plant communities, was conducted on the Ezemvelo Nature Reserve. The aim of the study was to identify, describe and classify plant communities of Ezemvelo Nature Reserve, and interpret them ecologically. The information derived from this study can then be used in the management of the Reserve. The floristic composition and habitat information were recorded in 210 sample plots. The data was captured in the TURBOVEG database and classified using the TWINSPAN numerical classification algorithm. The resulting phytosociological tables were compiled and organised using the MEGATAB computerised table management programme according to Braun-Blaunquet procedures. The data was also subjected to a Detrended Correspondence Analysis (DECORANA), processed by the PCOrd numerical ordination programme, to confirm the results of the classification. The ordination also illustrates any environmental gradients controlling the existence and distribution patterns of the different plant communities. Twenty-two major plant communities and 4 sub-communities were identified, described, and ecologically interpreted. The localities of the plant communities are indicated on map, compiled by using GIS. The plant communities on the Reserve are distributed in a mosaic of woodlands, grasslands and wetlands, based on the heterogeneous habitats created by the variations in topography, which is typical of Bankenveld vegetation. / Dissertation (MSc (Botany))--University of Pretoria, 2007. / Plant Science / MSc / unrestricted

It has been suggested that the Category 1 weed, Campuloclinium macrocephalum (Less) D.C has allelopathic potential, which would, at least partially, explain its apparent success as an alien plant in South Africa. Studies were done on the plant’s root, stems and leaves to determine where the strongest allelopathic potential can be found. Once it was determined that the leaves held the strongest potential, bioassay studies were conducted on lettuce (Lactuca sativa), Eragrostis tef, Eragrostis curvula and Panicum maximum with positive results found for C. macrocephalum’s allelopathic potential. Electron microscopy was performed to determine whether allelopathic substances originate and/or are stored on the surfaces of the leaf. Positive results proved that there are possible sources of allelochemicals on both adaxial and abaxial surfaces of young and mature leaves. A dipping experiment involving dichloromethane then followed to determine the solubility of the contents of the glands found on the leaf surfaces. It can be deduced from results of all of the experiments performed that C. macrocephalum is potentially allelopathic to dicotyledonous species and to grasses. Structures found on the leaves of the plant could possibly contain the allelochemicals used by the plant to ensure its successful invasive growth habits in South Africa. The allelopathic effects that this weed will have on desirable species should be considered within the broader context of its ability to interfere with those species. In this regard its competitive ability should also be studied. Campuloclinium macrocephalum is fast invading susceptible areas of South Africa; if continuous research on control and eradication of this plant is not carried out soon, the country could suffer grave economic losses. Copyright / Dissertation (MInstAgrar)--University of Pretoria, 2009. / Plant Production and Soil Science / unrestricted

With the increase in the number of fast-moving vehicles and the simultaneous development of road building technology, roadside bird mortality has become an increasingly important environmental issue that has the potential to do serious damage to already vulnerable bird populations. This project was therefore initiated after an alarming number of owls were found dead along the N17 and R550 roads in the rural areas between Springs and Devon in the East Rand highveld of Gauteng Province. Five hundred and fifty four owls of four species, namely Marsh Owls, the Red Data listed Grass Owl, Barn Owl and the Spotted Eagle Owl were collected on the stretches of the R550 and N17 during the period between October 2001 and September 2003. They accounted for 53.6%, 27.4%, 17.5% and 1.3% of the mortalities respectively. Unidentified species of owls accounted for the remaining 0.2%. It was found that the monthly mortality rates of the birds varied throughout the year, with the greatest losses being suffered during July, as opposed to relatively lower mortalities occurring during the warmer months. All carcasses were collected, their GPS locations plotted on a map, and ‘hotspot areas’ identified as places of highest incidences of mortalities of the owls. Vehicle-induced mortalities are then discussed in relation to these hotspots, in terms of vegetation and habitat descriptions, daily vehicle counts along the route, as well as fixtures found along the route. It was found that traffic density was indirectly proportional to owl mortalities, with higher traffic speeds definitely having an increasingly detrimental effect on the owl mortalities. Weather conditions also play a role in mortality counts, with the mortalities being significantly negatively correlated to rainfall. Moon phases were also related to the times of highest mortalities, however, this factor did not play a significant role in influencing road mortalities. Another factor that was studied was the influence of differing tarmac road surface temperatures as opposed to gravel road verge surface temperatures, and how these temperatures differed from the ambient temperature. It was found that there was not a big enough difference in the temperatures that would warrant (the previously thought notion) that the owls were attracted to the roads at night to gain heat. Gravel roads had very low incidences of owl mortalities with the highest mortalities recorded along tarmac roads that are bordered by open grasslands or cattle grazing paddocks. It was shown that tarmac roads, bordered by croplands, had a lesser effect on the owl mortalities. Another factor influencing the road mortalities of the owls is grain that is spilled on the road during transport. This initially seemed to be the major factor in attracting granivorous rodents to the roads, and in turn, attracting the owls to prey on them. Rodents identified from recovered pellets and the stomach contents of dead owls confirmed the fact that the majority of rodent prey items were indeed granivorous species, namely Mastomys natalensis and Rhabdomys pumilio. This is in disagreement with previous studies that indicated that a large proportion of the prey species of the Grass Owl was Otomys irroratus, a grass-eating species, even though a rodent trapping study to determine prey abundance within the area indicated a healthy population of O. irroratus. Further studies into prey items of the owls that were dissected indicated that the majority of the prey items recovered were not caught directly on the road as it was already partially digested, suggesting that the prey was caught prior to the owl being killed. From the pellet analyses, other prey items were also found to form part of the owls’ diets. It was found that insects formed largely the diet of the Marsh Owl during the spring, summer and autumn months, with them resorting to smaller rodents during the winter months. Spotted Eagle Owls also preyed almost exclusively on insects. Grass Owls, on the other hand, preyed on small mammals exclusively, with the very rare exception of some insects also being taken. Of all of the dead owls recovered on the roads, post mortems were carried out on only 78 of the carcasses. All of the dead owls examined were in good health prior to death. Various morphometrics of the examined owls were noted. Comparisons of body mass showed that females were larger than males for most species. This was also found for most other measurements as well. It was also found that, according to body mass comparisons, Barn Owls and Marsh Owls were significantly similar. Conducting ANOVA analysis on other morphometrics to determine gender differences, it was found that Grass Owl males were significantly different to females in terms of body mass and length. Marsh Owl males were significantly different to females in terms of body mass and tail length; with Barn Owl males being significantly different in terms of tarsus length to females. Except for Spotted Eagle Owl tarsus lengths all other measurements were in favour of females being significantly larger. These findings were also confirmed when applying the Dimorphism Index to all morphometrics measurements, especially body mass. The degree of parasite infestation was also studied during post mortem examinations. Very few cestodes and nematodes were found, with too few to have an effect on the overall health of the birds prior to death. The vegetation type was studied at transects that coincided with hotspot and non-hotspot sites. Using the PRIMER statistical software package, hotspot sites were found to have highest plant cover and diversity, whereas nonhotspot sites showed lowest plant cover and diversity, generally dominated by Hyparrhenia hirta. During these studies, the degree of available nesting habitat was determined and nesting sites were identified, using the ropedragging technique to flush out roosting and nesting owls that would otherwise have been impossible to find in the thick cover. It was found that Grass Owls preferred a habitat rich in thick grass cover that was relatively high (0.75 m–1 m). It was found that the grass species preferred by these owls were Eragrostis curvula, Paspalum sp., Setaria sp., Sporobolis sp., with few other small herbaceous plants. Marsh Owls, on the other hand, seemed not to be too partial regarding roosting and nesting sites, with them roosting and breeding in more mixed vegetation grasslands that had sparser cover, not reaching the height of the grass cover typical of the habitat preferred by the Grass Owls. Opposed to this were the non-hotspot vegetation sites. These sites were found to have vegetation cover unsuited to both the Marsh and Grass owls, with mixed H. hirta grassland not forming the dense cover, or the height, needed by those two species of owls. Foraging owls were also observed, with the vegetation type in the immediate vicinity noted. Vegetation types similar to breeding areas were noted in these foraging areas. Habitat preferences as well as breeding performance were noted for both grassland species of owls, and found to be directly related to land usage in terms of varying agricultural practices and regimes. Fallow, undisturbed lands were found to be highly productive for the owls. Lands planted with Eragrostis sp. were also found to be very productive, but only if left undisturbed for a period of time sufficient to allow the grassland owls to colonise it. Maize-planted fields were found to be utilised only as foraging fields and no breeding of owls was found to take place close to these fields. After extensive nest searching, it was found that both Marsh and Grass owls were breeding from late March to early June, with the Barn Owls breeding in October and again in March. Grass Owls occur in the study area because of the presence of a natural corridor of suitable habitat that runs parallel with the Blesbokspruit. This favourable habitat of the study area is thus conducive to high population density of grassland owls utilising these uncultivated patches of dense and tall vegetation. The high incidence of mortalities on the road in the study area is due to the concomitant high population densities. This healthy population seems to be sustaining the losses occurring on roads. Owls also seem to be gathering in larger numbers in hotspot zones because of the easy available prey, which are attracted to these high productive areas. Agricultural practices in the area lead to the spillage of grain on the road during transportation. Potential prey species foraging on the roads expose themselves to the nocturnal hunters offering an easy dinner. This process leaves these owls vulnerable to vehicle collisions. The overall population size may be larger than previously thought, not with standing the high mortalities already recorded. The small patches of viable habitat in the study area remains suitable for the breeding of the two grassland owl species allowing for such high densities to occur in the area. The Grass Owl, nonetheless, remains severely threatened as it already occurs as a high priority species for conservation concern in the Gauteng Province. This study provides the first assessment of this owl species of this scale in South Africa and this will ultimately promote the long-term survival of these owls. / Dr. V. Wepener

Please read the abstract in the section 00front of this document / Dissertation (MSc Agric (Animal Nutrition))--University of Pretoria, 2006. / Animal and Wildlife Sciences / unrestricted

Orientador: Ardemirio de Barros Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil / Made available in DSpace on 2018-07-24T02:55:15Z (GMT). No. of bitstreams: 1 Orsi_AngelaCristina_M.pdf: 4584140 bytes, checksum: 980f74a132481be6d8c7365b8f31e9b4 (MD5) Previous issue date: 1997 / Resumo: O foco desta dissertação é a geração de banco de dados espaciais da área compreendida entre os meridianos 47° 14' 37" e 46° 49' 12"W e os paralelos 22° 52' 47" e 23° 52' 47" e 23° 03' 50" S na cidade de Campinas, no Estado de São Paulo. Esta região foi escolhida devido ao grande desenvolvimento industrial e ao crescimento urbano verificado nas últimas décadas, quando, na maioria dos casos, o crescimento tem ocorrido de forma caótica gerando sérios impactos ambientais. Baseado na evolução das análises ambientais e na tecnologia de SIG foi possível montar um banco de dados digital e a partir dele selecionar áreas propícias à implantação de aterros sanitários. Utilizando-se de análises booleanas, para cada um dos atributos referentes as variáveis escolhidas foram atribuidos pesos em potência de 2 que possibilitou apresentação de valores individualizados,gerando 3.960 categorias. A partir destas categorias, utilizando-se de comandos do GRASS 4.1, os resultados foram satisfatórios, pois um mapa com 230 possibilidades foi gerado, sendo que a base digital geo-referenciada criada pode atender a outros objetivos em diferentes áreas do conhecimento científico / Abstract: The aim of this dissertation is to analyze the methodological approach of creating a digital spatial data base of the southem part of Campinas, in the State of São Paulo. This region has been chosen because of the large industrial development and urban growth shown in last decades, where of the cases this growth has generated serious environrnentalimpacts. The digital data base produced is based on environrnental evaluation analysis and GIS technology. Those methodologies were used with the specific purpose of selecting favorable areas for landtill, one of most commonlytechnical solution used for waste and garbage disposals. For each variable chosen different grades, were attributed in terms of power of two, which generating 3960 categories. The results achieved were considered safisfactory and a map with 230 possibilities was created. Another important conclusion of this dissertation is the plausibilityof use of this georeferenced digital data base created in several different areas of the scientificknowledge / Mestrado / Saneamento / Mestre em Engenharia Civil

A otimização de sistemas de pastejo não pode ser concebida simplesmente como a maximização da quantidade de forragem produzida ou ingerida pelos animais, sendo necessário considerar parâmetros que condicionam e determinam a persistência e a produtividade da pastagem. Nesse ponto, assegurar a capacidade de reposição de perfilhos assume importância fundamental. Dentro desse contexto, o objetivo deste experimento foi avaliar os efeitos de diferentes combinações entre intensidade e frequência de desfolha sobre a dinâmica, a densidade populacional de perfilhos e o acúmulo de forragem em pastos de capim-Mombaça pastejados por bovinos, visando determinar estratégias de manejo do pastejo que permitam obter alta produtividade e utilização de forragem, mantendo a estrutura do pasto dentro de limites aceitáveis de uso e garantindo, assim, a sua perenização. O experimento foi realizado na Universidade Federal de São Carlos, Araras, SP, entre 8 de janeiro de 2001 e 23 de fevereiro de 2002. Os tratamentos corresponderam a combinações entre duas intensidades (30 e 50 cm de resíduo) e duas freqüências de desfolha (pastejo iniciado com 95% e 100% de interceptação de luz do dossel - IL) e foram alocados às unidades experimentais conforme um delineamento de blocos completos casualizados e arranjo fatorial 2 x 2, com 4 repetições. O intervalo médio entre pastejos variou de 23 a 36 dias para os tratamentos de 95% e 100% IL, respectivamente, durante o período de primavera/verão. Durante o inverno, esses valores variaram de 95 a 186 dias. A altura do pasto em pré-pastejo foi um parâmetro confiável para ser utilizado como guia de manejo do pastejo baseado em condições de interceptação luminosa, uma vez que apresentou comportamento consistente e uniforme ao longo do período experimental. De forma geral, não houve diferenças entre as taxas de aparecimento e morte de perfilhos entre tratamentos. No entanto, taxas altas de mortalidade foram acompanhadas por taxas altas de aparecimento de perfilhos, com os maiores valores observados durante o período de primavera/verão relativamente a outono/inverno. Alta freqüência (95% IL) e/ou alta intensidade de desfolha (30 cm de resíduo) condicionaram a ocorrência de maiores taxas de mortalidade, propiciando uma maior renovação de perfilhos e, assim, um perfil mais jovem da população quando comparados aos tratamentos de desfolha menos freqüente (100% IL). Não houve diferença em densidade populacional de perfilhos (média de 380 perfilhos m -2 ), indicando que as diferenças em produção de forragem (18.230 a 27.220 kg MS ha -1 ) devem ter sido consequência de diferenças em produção por perfilho, com perfilhos jovens sendo mais eficientes no processo produtivo do que perfilhos mais velhos, fato que justificou a maior produção do tratamento 30/95 (27.220 kg MS ha -1 ). A densidade populacional de perfilhos variou com a época do ano, com os maiores valores registrados na época de verão, seguidos por aqueles do outono e primavera (400, 384 e 344 perfilhos m -2 , respectivamente). Os maiores valores de massa de forragem (8.100 kg MS ha -1 ) e altura em pré-pastejo (116 cm) ocorreram para os tratamentos que tiveram o pastejo iniciado com 100% IL comparativamente aos de 95% (5.400 kg MS ha -1 e 89,5 cm, respectivamente), pois estes permitiram um período de crescimento mais longo e, provavelmente, maior acúmulo de hastes e material morto, o que dificultou a manutenção do resíduo de 30 cm. Houve efeito de época do ano para todas as variáveis estudadas, indicando comportamento fortemente estacional do crescimento do capim-Mombaça. A partir dos resultados obtidos e considerando-se a importância da manutenção de uma alta taxa de renovação de perfilhos para otimização da produção e utilização de forragem, o pastejo deve ser iniciado quando os pastos atingem 90 cm de altura (95% IL) e interrompido quando rebaixado a 30 cm. / The optimization of grazing systems cannot be conceived simply as a maximization of the amount of produced herbage or dry matter consumed by grazing animals. It is necessary to take into account factors that condition and determine the persistence and productivity of pastures in order to ensure the ability of plants to replace dead tillers and maintain pasture stability. Against this background, the present experiment aimed at evaluating the effects of four combinations of grazing frequency and intensity on tiller dynamics/population density and herbage production of grazed Mombaça grass pastures to provide a firm basis for planning grazing management strategies that allow for high herbage productivity and utilization, preserving pasture structure within acceptable limits of use and ensuring its persistence. The experiment was carried out at Universidade Federal de São Carlos, Araras, SP, from 8 January 2001 until 23 February 2002. Treatments comprised combinations between two grazing intensities (post-grazing heights of 30 and 50 cm) and two grazing frequencies (grazing initiated at 95% and 100% canopy light interception - LI), and were assigned to experimental units (2000 m 2 paddocks) according to a complete randomized block design, following a 2x2 factorial arrangement, with 4 replications. The average grazing interval varied from 23 to 36 days for the 95 and 100% LI treatments, respectively, throughout the spring/summer period. During the winter, these intervals ranged from 95 to 186 days. Pre-grazing pasture height was a reliable grazing management guide based on canopy light interception, since it presented a homogeneous and consistent behavior during the entire experiment. There was no difference in tiller appearance and death rates among treatments. High tiller death rates, however, were accompanied by high tiller appearance rates, with higher values recorded during spring/summer in relation to autumn/winter. High grazing frequency (95% LI) and/or intensity (30 cm post-grazing height) resulted in the highest tiller death rates, causing a high tiller turnover that generated a younger profile in tiller population density compared to the low frequency treatments (100% LI). There was no difference in tiller population density among treatments (average of 380 tillers m -2 ), indicating that differences in herbage production (18,230 to 27,220 kg DM ha -1 ) must have been consequence of differences in production per tiller, with younger tillers being more productive than older ones, which was the main reason for the highest forage yield of the 30/95 treatment (27,220 kg DM ha -1 ). Tiller population density varied with time of the year, with higher values recorded during summer in relation to autumn and spring (400, 384 e 344 tillers m -2, respectively). The highest values for pre-grazing herbage mass (8,100 kg DM ha -1 ) and pre-grazing pasture height (116 cm) were recorded for the 100% LI treatments compared to 95% LI (5,400 kg DM ha -1 and 89.5 cm, respectively), since they resulted in longer grazing intervals than the 95% LI treatments. Accumulation of stem and dead material was certainly the main reason for the difference in herbage mass, and made it difficult for grazing pastures down to the target 30 cm post-grazing height. There was a season effect on all responses studied, indicating a very seasonal growth behavior of Mombaça grass pastures. Based on the results and baring in mind the importance of a high tiller turnover for optimizing herbage production and utilization, grazing must be initiated at 90 cm pre-grazing height (95% LI) and stopped at 30 cm post-grazing height.

This dissertation grew from an investigation of the farm Doornkloof in Irene, Pretoria. The farm was home to General Jan Smuts and it is here that he wrote his seminal philosophical work “Holism and Evolution” and found his own grass specie Digitaria Smutsii. The theoretical investigation is rooted in the interpretation of Holism, as an architectural theory, which informs the proposed design intervention. This study is informed by an analysis of the area of Irene, its origins and its future growth lead to the development of a holistic framework. This study proposes to inform the future socio-economic and historical importance of the farm as open public space for the citizens of Tshwane and Irene. The research intervention proposes a new architectural programmatic typology that will celebrate the importance of the Bankenveld landscape. The systematic rehabilitation of the grassland landscape will be achieved by introducing small scale interventions. The series of design interventions will rehabilitate the existing historical layers of the site, create new interest in the farm, improve the economic position of the Jan Smuts Foundation (the owners of the farm) and protect the landscape for the future generation users. / Dissertation MArch (Prof)--University of Pretoria, 2012. / Architecture / unrestricted