M.Ing. / Please refer to full text to view abstract

Les systèmes fourragers sont difficiles à gérer, en particulier à cause de leur sensibilité aux variations climatiques. La conception de systèmes fourragers flexibles, capables de garantir voire d'accroître leurs performances productives et environnementales face à ces variations, est donc un enjeu important. Cet objectif nécessite de la part de l'éleveur un comportement gestionnaire qui valorise la diversité biologique végétale et animale, et du territoire d'exploitation. Pour ce faire, cette thèse propose une démarche de modélisation systémique et de simulation dynamique permettant d'étudier une large gamme de systèmes fourragers sous différents contextes de production. Sa principale originalité réside dans la représentation des comportements gestionnaires sous forme de plans flexibles d'activités par lesquelles les éleveurs contrôlent les processus biologiques en oeuvre dans leurs systèmes. Un exemple d'application illustre comment, grâce au réalisme de cette représentation, la mise en oeuvre de la démarche contribue à stimuler l'apprentissage des experts et des chercheurs, en remettant en cause, à l'échelle du système fourrager, leurs hypothèses issues d'un diagnostic de pratiques d'éleveur à l'échelle de la parcelle. / Grassland-based livestock systems are difficult to manage, particularly because of their sensitivity to weather variations. The design of flexible systems, capable of maintaining or even increasing their productive and environmental performances in spite of such variations, is thus a major issue. Such aim requires that the farmer's management behavior be oriented toward the exploitation of the opportunities provided by plant, animal and farmland diversity. To this end, this thesis proposes an approach relying on systemic modeling and dynamic simulation that enables to study a wide range of grassland-based livestock systems under different production contexts. Its main originality is the modeling of management behaviors as flexible plans of activities through which the farmer controls the biological processes occurring within the system. Thanks to the realism of this representation, an example of application displays how the use of the proposed approach contributes to stimulate learning of experts and researchers by reviewing, at the system scale, their hypothesis formulated at the plot scale based on a diagnosis of the farmers' practices.

The general antibacterial activity of Drimia delagoansis, Petalidium oblongifolium and Ipomoea adenioides was determined using selected Gram-positive and Gram-negative bacteria. Only extracts or compounds with high antibacterial activity were then tested against the causative agent of heartwater, Ehlrichia ruminantium, since the latter requires specialised culturing conditions. The crude aqueous extract of D. delagoansis had low antibacterial activity with its highest MIC against Gram-negative bacteria being 20.0 mg ml-1 while the crude methanolic extracts of P. oblongifolium and I. adenioides had their highest antibacterial activity against Gram-negative bacteria at MIC's of 5.0 and 10.0 mg ml-1 respectively. Two compounds were isolated and identified from I. adenioides and an unidentified one was isolated from P. oblongifolium. The two compounds from I. adenioides proved to be caffeic acid with MIC's of 0.8 and 1.0 mg ml-1 against Gram-positive and Gram-negative bacteria respectively; and ethyl caffeate with MIC's of 0.4 and 1.0 mg ml-1 against Gram-positive and Gram-negative bacteria respectively. Synergism between the two compounds increased the respective MIC's to 0.4 and 0.2 µg ml-1 against Gram-positive and Gram-negative bacteria. The unidentified compound isolated from P. oblongifolium had a very low MIC of 2.5 µg ml-1 against E. ruminantium. / Thesis (PhD (Botany))--University of Pretoria, 2007. / Plant Science / unrestricted

Rinderpest, the most dreaded bovine plague, struck the cattle of the BaSotho in British Basutoland early in 1897. By December the murrain had spent itself, having reduced the cattle population by half As it did so, the rinderpest claimed the primary historical significance of an epidemic. By sharpening behaviour and illuminating latent or developing tendencies, the rinderpest helped to reveal the nooks and crannies of contemporary historical processes that would have otherwise eluded historical visibility. This thesis brings out the complexities and ambiguities surrounding the epidemic. It uses the crisis occasioned by the panzootic in its multifaceted manifestations as a prism through which we might view the complex aspects of contemporary historical processes. It goes beyond the narrow limits of the crisis itself to discerning the broader and wider historical patterns that the rinderpest helped to highlight.

Le rôle croissant de la pression pastorale sur la végétation en Tunisie, et en particulier dans la Dorsale tunisienne, a été étudié par plusieurs chercheurs (Long, 1959 ; Gounot et Schoenenberger, 1967 ; Le Houérou, 1959 et 1969). Cependant, ces études sous.estiment le rôle de l'homme et particulièrement l'activité d'élevage dans la variation spatiale de la végétation en Tunisie. L'un des premiers objectifs de cette thèse est donc, la production d'une carte de végétation à grande échelle qui prend en compte l'influence de l'homme sur le paysage. Les mutations récentes des modes de vie des paysans conduisent à placer l'élevage au centre des relations de l'homme à son milieu. Le rôle de la pression pastorale est considéré comme l'un des éléments explicatifs de la dynamique de la végétation forestière. Cette thèse adopte une démarche socio-économique et historique pour tester l'hypothèse suivante : bien que l'élevage soit reconnu comme un facteur d'influence dans la dynamique de végétation dans les marges arides du Tell oriental, son rôle n'a jamais été dominant. Il a été toujours associé à d'autres activités paysannes jugées nuisibles à la végétation comme le charbonnage, les incendies, les défrichements... L'abandon et/ou le ralentissement de ces activités dans le cadre des nouvelles mutations socio-économiques, ont fait de l'élevage un facteur déterminant dans la dynamique de la végétation. La thèse comprend trois parties : La première partie aborde la reconstitution de l'évolution qui a conduit au peuplement actuel. Cette évolution est dominée par la sédentarisation des pasteurs et a conduit à la genèse des douars actuels peuplés de petits agriculteurs-éleveurs. Dans ce système de production, la place de l'élevage pastoral est prépondérante et persistante. La deuxième partie de la thèse montre les analyses qui ont permis de réaliser une cartographie détaillée du couvert végétal. La cartographie de la végétation est utilisée pour faire le point sur l'état de conservation du couvert végétal et procéder à une estimation qualitative et quantitative des ressources fourragères disponibles au sein de chaque unité spatiale homogène. Dans la troisième partie La troisième partie analyse principalement les enquêtes, les observations de terrain, les données sur les effectifs des troupeaux, les sources d'alimentation du bétail et l'évolution de son état corporel. L'analyse de ces données permet de définir les systèmes d'élevage développés dans la région étudiée, de cartographier la répartition de leur pression pastorale sur la végétation forestière et steppique, à partir de chaque foyer de peuplement assurant la gestion du troupeau et de l'espace. / The growing role of grazing pressure on vegetation in Tunisia, and in particular in the Tunisian Dorsal has been studied by several researchers (Long, 1959; Gounot et Schoenenberger, 1967; Le Houérou, 1959 and 1969). However, these studies neglect the role of man and especially the breeding activity in the spatial variation of vegetation in Tunisia. One of the primary objectives of this thesis is the production of a large.scale vegetation map that takes into account the influence of man on the landscape. Recent changes in farmer's lifestyles lead to put livestock in human relations center in the middle. The role of grazing pressure has become one of the factors explaining the dynamics of forest vegetation. This thesis adopts a socio-economic and historical approach to test the assumption that farming is recognized as an influential factor in the dynamic vegetation in arid margins Tell East; its role has never been dominant. It was always associated with other activities deemed harmful to vegetation peasant like coal, fire, land clearing ... The abandonment and / or deceleration of these activities in the framework of the new socio-economic changes have made Livestock a major factor in the dynamics of vegetation. The thesis has three parts: The first part deals with the reconstruction of the evolution that led to the current settlement. This evolution is dominated by the settlement of pastoralists and has led to the genesis of the current douars inhabited by small farmers and breeders. In this production system, instead of pastoralism is predominant and persistent. The second part of the thesis shows the analysis that enabled a detailed land cover mapping. The vegetation mapping is used to take stock of the vegetation cover conservation status and conduct a qualitative and quantitative estimation of forage resources available within each homogeneous spatial unit. In the third part, based primarily on surveys, field observations, data on the number of livestock, livestock feeding sources and changes in body condition. Analysis of these data to define farming systems developed in the study area; map the distribution of their grazing pressure on forest and steppe vegetation, from each stand home use management herd management and space.

This study explores how livestock in rural communities were accessed, used as livelihoods portfolios and how off-farm activities and portfolios such as social grants, support from family members and employment assisted the rural poor to build their asset base. Empirical data was collected from 26 villages in the three districts. In particular the study examines firstly, the nature of rural poverty in these villages in the three districts and how households with and without livestock (cattle, sheep, goats, dogs, pigs, cats, ducks, horses and donkeys) used livestock local knowledge to sustain a living. Secondly it explores how the local government and related rural development agencies, intervened in livestock production and the thesis highlights the problematic nature of these interventions, and the implications this has for the form and nature of livestock ownership and use in relation to rural livelihoods. Arising from this, the thesis thirdly explores Ruliv‟s through concrete case studies, the challenges, constraints and implications of a pre-dominant top-down approach to rural development. Contrary to this approach, the study illustrates, through the Rhoxeni case study, the potential effectiveness of a „bottom-up‟ actor oriented approach to rural development. Fourthly, the study explores how local government initiatives intervened in the development of a rural livestock project in Alfred Nzo District Municipality through the Integrated Sustainable Rural Development Programme Goat Project. Here iv the concerns of „commercialisation‟ of livestock production are explored and the thesis points to the implications that the exclusion of social and cultural meanings of livestock have for assumed paths of commercialisation and its associations with development. Fifthly the study explores the potentiality of emerging black commercial farmers who had acquired large areas of agricultural land through local government interventions (Land Redistribution Agricultural Development) but who lacked further support and capacity to transform themselves into commercial farmers. The thesis concludes that their livestock and crop farming activities remained more subsistence and livelihood based, than any transition to expected technical market oriented commercial farming. Overall, the thesis argues that while local government planning for rural development prioritised commercial agriculture as the basis of rural development and the key mechanism of rural poverty alleviation in developmental policies (PGDP, IDP, LED), rural poverty has actually been deepening. In this context, the study argues that the value of livestock to the rural poor lies „outside‟ of its assumed economic value and is more firmly and determinedly located in its social meanings and values, despite these significant levels of material poverty. This has major implications for understanding livelihoods, engaging livestock agency, defining farming and what it means to be a „farmer‟ and engaging with prevalent understandings and practices directed at rural development.

This study investigated the vegetation and soil characteristics in relation to distance from water points under different land management systems in semi-arid rangelands of South Africa. Six study sites, two each from communal grazing, commercial farming and game reserves were selected. Two watering points were selected in each study site. Two 500 m transects were laid from the selected watering points. Each transect was divided into sub-transects at 25 m, 50m, 100m, 200m, 300m and 500m from water points. A 100 m2 plot was marked in each sub-transect to record grass biomas, species composition, structure and distribution of woody vegetation and physical and chemical soil properties. Data were collected for two seasons 2012/13 (winter and summer). Thirty and 41 grass and woody species respectively were identified in all study areas. The most common and dominating grass species include Cynodon dactylon, Digitaria eriantha, Eragrostis obtusa, Setaria sphacelata and Sporobolus fimbriatus. Cynodon dactylon and S. sphacelata occurred more abundantly (p < 0.05) in the game reserves than in the other land management catergories. All the grass species had similar (p > 0.05) abundance along distance gradient from water points. Grass dry matter (GDM) showed significant differences (p < 0.05) between and within land management systems. However, GDM was not significantly affected by season, location of water point within each farm or reserve and distance along water points. Acacia karoo, Coddia rudis and Ehretia rigida were the most dominant woody species. Tree equivalent (TE) density of all encroaching woody plants combined was significantly (p < 0.05) higher on the communal area (1732 TE ha-1) than the commercial ranches (1136 TE ha-1) and game reserves (857 TE ha-1), but with no marked variations along distance from water points under all the land management systems. The electric conductivity (EC) was significantly (P < 0.01) higher in game reserves than in communal grazing areas and ranches. Soil organic matter percentage showed greatest and lowest values in the game reserves and commercial respectively. Soil pH and bulk density did not vary but soil organic matter (SOM), EC, bulk density and soil compaction were significant different with no increasing or decreasing trends. Soil properties were affected by herbivore pressure and trampling around water points with inconsistence magnitude and direction. In conclusion, grass species composition and GDM did not respond to distance from water points because either grazing gradient was absent or the length of transects was not enough to explain the absence or presence of gradients. High proportion of A. karoo and high densities of seedlings and saplings would seem as very good indicators of the woody vegetation changes in the different land management systems and distance from water points. The soil quality indicators around the water-points showed that livestock and game affected soil parameters.

This thesis describes issues of Agriculture of the European Union, with focus on its socioeconomic and economic aspects. It also describes issues of EU's international trade with agriculture products.

Made available in DSpace on 2016-01-26T18:56:28Z (GMT). No. of bitstreams: 1 Fabricio Loureiro de Almeida.pdf: 435983 bytes, checksum: 629e4d1dc48dd21c0cc71010136fa202 (MD5) Previous issue date: 2013-02-28 / Soybean cultivation is extremely risky when you have soil conditions with low clay content, low water retention and irregular rains. Therefore maintenance of mulch can reduce the risks for the production of this culture so important for Brazilian agribusiness. Aiming at improving the qualities of the soil tillage system has been widely adopted in Brazil as having the benefit of maintaining ground cover, preservation or increase organic matter and improve the physical, chemical and biological soil. Within this context, the use of tropical forages in integrated crop and livestock farming livestock integration forest constitutes an excellent option for the production of straw and roots and thus improve the efficiency of water use in addition to improving the chemical characteristics and biological soil. This experiment consists of two chapters. Chapter I: Crop Rotations in different production systems to improve the environment of soybean cultivation in western São Paulo. Chapter II: Productivity of soybean in different positions between rows of eucalyptus in intercropping system. The experiment was conducted in the experimental area Campus II of the University of Western São Paulo in Presidente Prudente (SP) in an Ultisol, between May 2010 and March 2012. We tested five different systems in separate plots, with sizes ranging between 1.0 and 1.8 ha and a maximum distance of 500m between them. The systems were: 1) brachiaria / + Brachiaria eucalyptus / eucalyptus / soybean, 2) brachiaria / corn Brachiaria + / brachiaria / soybean, 3) peanut / brachiaria / soy / brachiaria / soybean; 4) Irrigated Pasture, 5) Witness pasture degraded. The results were submitted to analysis of variance, and means were subjected statistically by Tukey test at 5% probability. / O cultivo de soja é mais arriscado quando se tem condições de solo com baixos teores de argila, baixa retenção de água e chuvas irregulares. Portanto uma manutenção de cobertura morta pode diminuir os riscos para a produção dessa cultura. Visando essa melhoria nas qualidades do solo o sistema de semeadura direta tem sido amplamente adotado no Brasil tendo como beneficio a manutenção da cobertura do solo, preservação ou aumento da matéria orgânica e a melhoria das propriedades físicas, químicas e biológicas do solo. Dentro desse contexto, o emprego de forrageiras tropicais em sistemas de integração lavoura pecuária e integração lavoura pecuária floresta constitui-se uma excelente opção para a produção de palha e raízes e, dessa forma melhorar a eficiência de uso de água alem de melhorar as características químicas e biológicas do solo. Esse experimento consiste de dois capítulos. Capitulo I: Efeito dos sistemas de produção na qualidade do solo e na produtividade de soja no oeste paulista. Capitulo II: Produtividade de soja em diferentes posições entre renques de eucalipto em sistema consorciado. O experimento foi conduzido em área experimental do Campus II da Universidade do oeste paulista em Presidente Prudente (SP), em um Argissolo Vermelho, entre maio de 2010 e março de 2012. Foram testados cinco diferentes sistemas separados em talhões, com dimensões variando entre 1,0 e 1,8 ha e com distância máxima entre eles de 500m. Os sistemas foram: 1) braquiária/eucalipto+braquiária/eucalipto/soja;2)braquiária/milho+braquiária/braquiária/soja; 3)amendoim/braquiária/soja/braquiária/soja; 4)Pastagem irrigada; 5)Testemunha com pastagem degradada. Os resultados foram submetidos à analise de variância, e as médias foram submetidas estatisticamente pelo teste de Tukey, à 5 % de probabilidade.

Made available in DSpace on 2016-07-18T17:51:12Z (GMT). No. of bitstreams: 1 Fabricio Loureiro de Almeida.pdf: 435983 bytes, checksum: 629e4d1dc48dd21c0cc71010136fa202 (MD5) Previous issue date: 2013-02-28 / Soybean cultivation is extremely risky when you have soil conditions with low clay content, low water retention and irregular rains. Therefore maintenance of mulch can reduce the risks for the production of this culture so important for Brazilian agribusiness. Aiming at improving the qualities of the soil tillage system has been widely adopted in Brazil as having the benefit of maintaining ground cover, preservation or increase organic matter and improve the physical, chemical and biological soil. Within this context, the use of tropical forages in integrated crop and livestock farming livestock integration forest constitutes an excellent option for the production of straw and roots and thus improve the efficiency of water use in addition to improving the chemical characteristics and biological soil. This experiment consists of two chapters. Chapter I: Crop Rotations in different production systems to improve the environment of soybean cultivation in western São Paulo. Chapter II: Productivity of soybean in different positions between rows of eucalyptus in intercropping system. The experiment was conducted in the experimental area Campus II of the University of Western São Paulo in Presidente Prudente (SP) in an Ultisol, between May 2010 and March 2012. We tested five different systems in separate plots, with sizes ranging between 1.0 and 1.8 ha and a maximum distance of 500m between them. The systems were: 1) brachiaria / + Brachiaria eucalyptus / eucalyptus / soybean, 2) brachiaria / corn Brachiaria + / brachiaria / soybean, 3) peanut / brachiaria / soy / brachiaria / soybean; 4) Irrigated Pasture, 5) Witness pasture degraded. The results were submitted to analysis of variance, and means were subjected statistically by Tukey test at 5% probability. / O cultivo de soja é mais arriscado quando se tem condições de solo com baixos teores de argila, baixa retenção de água e chuvas irregulares. Portanto uma manutenção de cobertura morta pode diminuir os riscos para a produção dessa cultura. Visando essa melhoria nas qualidades do solo o sistema de semeadura direta tem sido amplamente adotado no Brasil tendo como beneficio a manutenção da cobertura do solo, preservação ou aumento da matéria orgânica e a melhoria das propriedades físicas, químicas e biológicas do solo. Dentro desse contexto, o emprego de forrageiras tropicais em sistemas de integração lavoura pecuária e integração lavoura pecuária floresta constitui-se uma excelente opção para a produção de palha e raízes e, dessa forma melhorar a eficiência de uso de água alem de melhorar as características químicas e biológicas do solo. Esse experimento consiste de dois capítulos. Capitulo I: Efeito dos sistemas de produção na qualidade do solo e na produtividade de soja no oeste paulista. Capitulo II: Produtividade de soja em diferentes posições entre renques de eucalipto em sistema consorciado. O experimento foi conduzido em área experimental do Campus II da Universidade do oeste paulista em Presidente Prudente (SP), em um Argissolo Vermelho, entre maio de 2010 e março de 2012. Foram testados cinco diferentes sistemas separados em talhões, com dimensões variando entre 1,0 e 1,8 ha e com distância máxima entre eles de 500m. Os sistemas foram: 1) braquiária/eucalipto+braquiária/eucalipto/soja;2)braquiária/milho+braquiária/braquiária/soja; 3)amendoim/braquiária/soja/braquiária/soja; 4)Pastagem irrigada; 5)Testemunha com pastagem degradada. Os resultados foram submetidos à analise de variância, e as médias foram submetidas estatisticamente pelo teste de Tukey, à 5 % de probabilidade.