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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

An historical overview and evaluation of the sustainability of the Land Redistribution for Agricultural Development (LRAD) Programme in South Africa

Tsawu, Simphiwe 03 1900 (has links)
Thesis (MPhil)--Stellenbosch University, 2006. / ENGLISH ABSTRACT: Land policy in South Africa prior to 1994 was used as a political instrument to discriminate against the black population by preventing them from accessing land. The National Party government promulgated various laws that allowed the government to forcefully removed millions of black people from their original land to the so-called reserves. These removals resulted in extensive landlessness, homelessness, poverty, unemployment and economic disempowerment of blacks in South Africa. Prior to 1994 the explosive issue of land reform was the subject of debates between the different political parties, with diverse viewpoints on what should be done. Following much debate, when the African National Congress (ANC)-led government took over in 1994, a market approach of “willingbuyer, willing-seller” (WBWS) was adopted, with as goal the redistribution of 30% of farmland to blacks by 2015. A land reform programme was instituted, consisting of three programmes, namely land restitution, land redistribution and land tenure reform. The ANC government originally regarded land reform as a key programme to address unequal patterns of resource distribution, but there seems to be a broad consensus that land reform has changed its originally objectives. By December 2004, all aspects of the land reform programme had only transferred an area equal to 4, 3 % of commercial agricultural land to blacks. At the National Land Summit of July 2005, the majority of delegates agreed that the WBWS principle in the land redistribution process is no longer appropriate and called for alternative policies, such as expropriation to fast track the process of redistribution in South Africa. This integrated assignment focuses on the Land Redistribution for Agricultural Development (LRAD) sub-programme of the land redistribution programme in South Africa. It gives an overview of the history of land issues and land reform in South Africa. The study then evaluates the sustainability of the LRAD programme and investigates the many problems and challenges that still face the programme. The research is mainly literature based, and combines primary and secondary sources. The study concluded that the LRAD programme will not meet its well-known objective of transferring 30% of farmland to blacks by 2015, unless radical steps are taken to change the policy. A section on proposed policy changes is included. It is felt that if sustainable development principles and resolutions that were taken on the recent Land Summit are taken seriously and implemented successfully, the LRAD programme may achieve its target by 2015. / AFRIKAANSE OPSOMMING: Voor 1994 is die Grondbeleid in Suid Afrika gebruik as ʼn politieke instrument om teen die swart bevolking te diskrimineer, deur hulle daarvan te weerhou om grond te bekom. Die Nasionale Party regering het verskeie wette gepromulgeer wat die regering toegelaat het om miljoene swart mense van hul oorspronklike grond te verwyder, na die sogenaamde reservate. Hierdie verskuiwings is die oorsaak van grootskaalse grondloosheid, dakloosheid, armoede, werkloosheid en ekonomiese ontmagtiging van swart mense in Suid Afrika. Voor 1994 was die eksplosiewe aspek van grondhervorming die onderwerp van debatte tussen die verskillende politieke partye, met uiteenlopende sienings oor wat gedoen moes word. Na baie debat, toe die ‘African National Congress’ (ANC) regering in 1994 oorneem, is ʼn gewillige koper, gewillige verkoper’ beleid aanvaar, met as doel die herverdeling van 30% van plaasgrond aan swartes teen 2015. ʼn Grondhervormingsbeleid in ingestel wat bestaan uit drie programme, naamlik grondrestitusie, grondherverdeling en grondeienaarskap hervorming. Die ANC regering het grondhervorming oorspronklik as ʼn sleutel program beskou om die ongelyke patroon van hulpbron verspreiding aan te spreek, maar daar is tans ʼn breë konsensus dat grondhervorming se oorspronklike doelwitte verander het. Teen Desember 2004, was daar, ingevolge alle aspekte van die grondhervormingsbeleid, slegs ʼn gebied gelyk aan 4,3% van kommersiële landbougrond oorgedra aan swart mense. By die Nasionale Grond Spitsberaad van Julie 2005 het die meerderheid van die deelnemers saamgestem dat die ‘gewillige koper, gewillige verkoper’ beleid nie langer geskik was nie, en is daar vir alternatiewe beleide gevra, soos onteiening om die proses van grondherverdeling te bespoedig. Hierdie geïntegreerde werkstuk fokus op die Grondherverdeling vir Landbou Ontwikkeling subprogram van die grondherverdeling program in Suid-Afrika. Daar word ʼn oorsig gegee van die geskiedenis van grondaangeleenthede en grondhervorming in Suid Afrika. Die studie evalueer die volhoubaarheid van die program en stel ondersoek in na die baie probleme en uitdagings wat die program nog in die gesig staar. Die studie is meestal literatuur-gebaseerd en kombineer primêre en sekondêre bronne. Die studie lei af dat die program nie sy welbekende doelwit van die oordra van 30% van plaasgrond na swart mense teen 2015 sal bereik nie, tensy radikale stappe geneem word om die beleid te wysig nie. Die studie sluit ʼn afdeling met voorgestelde beleidsveranderinge in. Daar word gevoel dat as volhoubare ontwikkelings-beginsels en besluite wat by die Grond Spitsberaad ernstig opgeneem en suksesvol geïmplementeer word, die program sy doelwitte teen 2015 mag bereik.
162

Fish-farming in South Africa : a study of the market environment and the suitable species

Mahieu, Alain 04 1900 (has links)
Thesis (MPhil)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Emerging global trends towards sustainable development have placed emphasis on the need to create sustainable food value chains. Many food value chains are becoming weakened through their reliance on eco-systems that are deteriorating. Furthermore, while food systems are under threat, global food consumption is on the rise. The conundrum seems inescapable. Humanity’s food supply methods have moved on from hunter-gatherer characteristics apart from the exception of the fishing industry. The current generation may be the last to witness the wide-spread practice of fishing. Aquaculture, and in particular fish-farming, has begun to show much potential as a method of producing sustainable sources of protein. Whether this can be utilized in the South African context is a challenge that needs to be verified. This research, presented as two articles, explores the potential for the development of the fish-farming sector in South Africa, and recommends suitable species. Although there is some literature on how fish-farming may have a place in South Africa’s sustainability quest, it is scarce. This research aims to enhance the literature base on fish-farming in South Africa, as well as provide further evidence on what the true potential is for fish-farming in South Africa. This was done through a series of primary and secondary data collection methods that allow for a thorough analysis of fish-farming in South Africa and the species involved. The analysis revealed that the fish-farming sector and the cultivatable species in South Africa are met with an array of opportunities and challenges. Overcoming these challenges will open the doors to exploit the opportunities available. / AFRIKAANS OPSOMMING: Opkomende globale tendense weerspieël dat dit noodsaaklik is dat klem gelê moet word op volhoubare ontwikkeling en dat dit van uitterste belang is om volhoubare voedsel waardekettings te skep. Verskeie voedsel waardekettings raak verswak deur hul afhanklikheid van eko-stelsels wat vernietig word. Verder, terwyl voedsel stelsels bedreig word, is globale verbruik van voedsel besig om te verhoog. Dié raaisel lyk onvermydelik. Mensdom se huidige voedselvoorraad metodes het aansienlik ontwikkel van dié van die jagter-versamelaars, met die uitsondering van die visbedryf. Die huidige generasie mag die laaste wees, wat die wyd verspreide praktyk van visvang beoefen, om daarvan te getuig. Akwakultuur, in besonder vis-boerdery, het begin om potensiaal te wys as 'n volhoubare bron in die vervaardiging van proteïen. Of dit in die Suid-Afrikaanse konteks gebruik kan word, is 'n uitdaging wat geverifieer moet word. Hierdie navorsing, wat aangebied word as twee tydskrifartikels, ondersoek die potensiaal vir die ontwikkeling van vis-boerdery in Suid-Afrika, en beveel ook gepaste spesies aan. Alhoewel daar sommige artikels is oor hoe vis-boerdery kan in pas in Suid-Afrika se soeke na volhoubaarheid, is dit skaars te vinde. Die navorsing beoog om die literatuur basis van vis-boerdery in Suid-Afrika op te skerp, en ter selfde tyd verdere bewys te gee oor die ware potensiaal van vis-boerdery in Suid-Afrika. Dit was gedoen deur 'n reeks van primêre en sekondêre data-insameling metodes wat voorsiening maak vir 'n deeglike ontleding van visboerdery in Suid -Afrika en die spesies betrokke. Die ontleding het getoon dat die vis-boerdery bedryf en die aankweek spesies in Suid-Afrika verskeie geleenthede en uitdagings in die gesig staar. Oorwinning van hierdie uitdagings sal dit moontlik maak om die beskikbare geleenthede te ontgin.
163

Analysis of the impact of training and capacity building by CASP on raising the income levels of emerging farmers in Limpopo Province

Xaba, Sharon Thembi 12 1900 (has links)
Thesis (MDF)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The South African government continues to provide post-settlement support to emerging farmers, with the objective of improving productivity through targeted funding or conditional grants. The Comprehensive Agricultural Support Programme (CASP), which came into effect in 2004, provides funding targeted at supporting emerging farmers. CASP has six pillars, of which this study focused on one, which is capacity building and training. The study investigated the assessment of the impact of training on the projects’ beneficiaries who had benefited from the CASP pillar of training and capacity building in the Limpopo Province. The methodology applied was the difference-in-difference technique. Projects that benefited from funding were regarded as the treatment group and those that did not benefit from the programme were regarded as the control group. The justification for the research was that while the government had financed CASP through fiscal allocation since 2004, because CASP is a conditional grant, there was a need to review the programme, focusing on establishing whether the budget allocation had achieved its intended objectives during this time. The objectives of the study were to measure whether there had been an improvement in the beneficiaries’ income levels. It focused on the status of the projects prior to the beneficiaries receiving training and benefiting from capacity building, and what the status was after receiving training through the programme, with the key determinant being an increase in income levels. Not all funded projects had benefited from the particular pillar investigated here. The selection of the beneficiaries to be trained was based on a skills audit which treated the groups as homogeneous, which was found to be inappropriate because of the differences in the prior skills, education levels and the specific interests of individuals. The findings were that there was variation in the increase of income levels. There was a positive relationship between training and reported increase in income levels in some projects, and a negative relationship between training and income levels for other projects. It was interesting that income levels increased for projects that had benefited from the CASP pillar of training and capacity building when the projects were analysed as a group, but when projects were analysed individually, it was revealed that there was a marginal decrease in income levels. There should be a shift in policy. The focus on training and capacity building should be a priority and should occur prior to the projects receiving infrastructure support. The 10% of the total CASP budget allocated for training and capacity building needs to be reviewed, taking into account that low skills levels continue to be the main reason why projects are not sustainable. There is also a need to review the impact of training. The type of training offered should not be generic for all projects, it should be differentiated to suit the both the people and the commodities concerned and should be more biased towards entrepreneurship, as this would enable emerging farmers to grow their business units and realise increased income levels.
164

Le rôle des organisations paysannes dans la professionnalisation de l'agriculture en afrique subsaharienne : le cas du Cameroun. / The role of peasan organizations in the professionnalization of agriculture : the case study of Cameroon

Achancho, Valantine 17 December 2012 (has links)
Dans tous les continents et en particulier dans les pays d'Afrique subsaharienne, les organisations paysannes ont toujours été au centre des politiques de développement de l'agriculture. Nombreuses et diversifiées, les organisations paysannes du Cameroun font l'objet d'une attention particulière de la part des pouvoirs publics qui depuis près de quatre décennies mettent en place des programmes de développement dont l'objectif principal est d'appuyer la professionnalisation de l'agriculture, à travers une structuration organisée du milieu rural. Le présent travail de recherche analyse le rôle des organisations paysannes dans la professionnalisation de l'agriculture. Il aborde et clarifie les notions de professionnalisation de l'agriculture et d'organisations paysannes à travers une approche sociologique et met en évidence la logique des programmes dits de professionnalisation, de même que les dynamiques d'organisation de producteurs agricoles qui évoluent au Cameroun. L'étude s'appuie sur des données d'observation des dynamiques d'organisations paysannes au Cameroun de 1994 à 2012 ainsi que du suivi des initiatives des projets d'appui aux organisations paysannes et aux filières agricoles. Les données collectées portent également sur une enquête réalisée auprès de 70 organisations paysannes dans les régions de l'Ouest, du Nord-ouest, du Sud-ouest, du Littoral et du Sud du Cameroun. Ces enquêtes ont permis de réaliser des entretiens de groupe avec environ 350 paysans issus d'organisations paysannes, et en particulier d'avoir des discussions plus approfondies avec 20 responsables d'organisations paysannes sur leur parcours et la nature de leur leadership. Sur la base des résultats obtenus, il a pu être établi que la professionnalisation de l'agriculture s'inscrit dans la logique des nouvelles offres « d'innovation » proposées par les partenaires du développement, avec pour objectif de contribuer au développement d'une agriculture plus performante dans les pays d'Afrique subsaharienne." [...] Suite et fin du résumé dans la thèse. / In all continents and especially in the sub Saharan countries, farmers organizations have always been at the center of development policies in agriculture. These farmers' organizations in Cameroon though many in number and diversified, are subject to particular attention by public authorities, who close to four decades today are putting in place development programs with main objective, being the support to professionalization of agriculture through the organization and the structuring of the rural milieu. This research analyses the role of farmers' organizations in the professionalization of agriculture. It treats and clarifies the notion of agricultural professionalization and farmer organizations using a sociological approach and put into evidence the logic of programs with focus on professionalization. It also treats the dynamics of farmer organizations in agriculture in Cameroon. The study is based on data from the observation of farmer's organizations dynamics in Cameroon from the year 1994 to 2012, and also, the follow up of initiatives of support projects to farmer organizations and the agriculture sub-sectors. Data collected is also from a survey carried out in 70 farmer organizations in the West, North West, South West, Littoral and South regions of Cameroon. These surveys permitted group discussions with about 350 farmers from different farmer organizations, and enabled particularly more elaborate discussions with 20 leaders of farmer's organizations on their experience and nature of leadership. On the basis of results obtained, it was established that the professionalization of agriculture is inscribed in the new logic of the supply of innovations proposed by development partners, with the aim of contributing to a more competitive agriculture sector in sub Saharan Africa." Last and final summary in the thesis.
165

PRODUCTION AND NUTRITION RECOVERY OF CROPS IN A RECIRCULATING AQUAPONIC SYSTEMS

Teng Yang (7037720) 16 August 2019 (has links)
<div>The goal of this research was to improve crop yield and quality and enhance nutrient use efficiency of aquaponics for the development of sustainable aquaponic production system. Aquaponics is the integration of aquaculture and hydroponics by recirculating water and residual nutrients resulting from aquaculture wastewater into hydroponic crop production. The project had four objectives. The first objective was to characterize nutrient composition and accumulation in recirculating water and plant parts of tomato, basil, and lettuce grown in aquaponic systems, and to compare their growth and yield with those grown in hydroponic systems. The second objective was to determine the effects of feeding management regime on water quality, crop yield and quality, and N use efficiency for vegetable and herb production in recirculating aquaponics in comparison to hydroponics. The third objective was to optimize water-flow rate for efficient aquaponic system for maximum crop yield. The fourth objective was to investigate and compare the N and P mass balance between aquaponics and hydroponics. Four conclusions were determined that 1) Aquaponic solution was deficient in Ca and/or Mg leading to plant nutrient deficiency but sufficient or high in P; And luxuriant nutrient profiles in hydroponics are not necessary to enhance crop yield in aquaponics as long as key factors affecting crop yield are identified and properly addressed. 2) Uniform feeding regime improved water quality by reducing toxic ions and enhancing initial nutrient availability and considerably increased the yield, quality and nitrogen use efficiency (NUE) of crops in aquaponics as close or similar to those in hydroponics. 3) Flow rate is an important factor affecting water quality parameters and optimizing flow rate is essential to maximize aquaponic crop production and improve energy efficiency; High hydraulic loading rate at 3.3 m3/m2-day improved performance and yield of all crops in an aquaponics system regardless of their growth rate, but the water hydraulic loading rate for fast-growing and medium-growing crops can be reduced to 2.2 m3/m2-day without production reduction. 4) Plant species had significant influence on N and P removal and mass balance in aquaponics and hydroponics; Fruity vegetables showed better growth adaption in aquaponic system, while yields of leafy vegetables may be reduced when grown in aquaponics than hydroponics; Aquaponics is more efficient than hydroponics releasing less environmental wastes, however, N and P use efficiency in aquaponics and hydroponics can be further improved via proper management.</div><div>The important findings obtained from this research will fill the knowledge gap in aquaponic research and provide new management strategies to improve quantitative study of aquaponic crop production and new management strategies for cultivating crops in aquaponics. The findings will also greatly contribute to the commercial aquaponic development, and ultimately improve food security and resource use efficiency in the US and global agricultural production.</div>
166

La microfinance au service d’une agriculture durable, illusion ou réalité ? : le cas de Madagascar (région de l’Itasy) / The microfinance in the service of sustainable agriculture , illusion or reality : the case of Madagascar (region of Itasy)

Ramanantseheno, Domoina 29 November 2012 (has links)
Le secteur agricole regroupe non seulement plus de la moitié de la population rurale pauvre des Pays les Moins Avancés (PMA), mais aussi plus de 60 % de la population active. La majorité des ruraux pauvres tire le principal de ses revenus de l’activité agricole. Le développement agricole peut donc être considéré comme un puissant facteur d’atténuation de la pauvreté. Cependant, le problème du financement des petites exploitations familiales dans les PMA reste un problème non résolu.Si l’on considère que la microfinance est un outil de réduction de la pauvreté, quel que soit le secteur d’activité auquel elle s’applique, alors l’effet optimal de sa mise en oeuvre devrait être constaté là où se trouve la plus grande partie de la population pauvre. Le secteur agricole des Pays Moins Avancés devient alors le terrain privilégié de cette expérimentation. Le défi qui s’impose à la microfinance est donc non seulement de fournir le capital aux agriculteurs, leur permettant d’accroître leur productivité, mais aussi de favoriser une agriculture au service de l'environnement.Par conséquent, le rôle spécifique de la microfinance dans l’agriculture, et plus particulièrement pour les petites exploitations familiales des PMA, est donc questionné.La microfinance saura-t-elle se présenter comme une alternative aux problèmes de financement de l’agriculture familiale ou ne restera-t-elle qu’une illusion ? / In the Less Advanced Countries, the agricultural sector is constituted not only by more than half of the rural population but also by over 60% of the active population. The majority of the poor rural people obtain their main resource incomes from the agricultural activities. The agricultural development could thus be considered as an attenuation factor of the poverty. However, the problem of the financial support toward the small family agricultural exploitation in the Less Advanced Countries still remains an unsolved issue.If microfinance is considered to be a tool for reducing poverty in any activity sector where it is used, then the optimal effect of its implementation should be observed in the area where the majority of poor population is located. So, the agricultural sector of the Less Advanced Countries becomes a privileged field of this experimentation. The challenge that the microfinance has to face is not only to provide financial support to the farmers for allowing them to increase their productivity, but also to promote an agriculture contributing to the environment.As a result, the specific role of the microfinance in the field of agriculture, in particularly for the small family agricultural exploitation in the Less Advanced Countries is questioned.Will the microfinance be able to present itself as an alternative for the issue of the financial support toward the family farms or will it be just an illusion?
167

Développement hydro-agricole au sud-est du lac Alaotra (Madagascar). Histoire, limites et pespectives de la maîtrise de l'eau / Hydro-agricultural development in the southeast of the lake Alaotra (Madagascar). History, limitations and perspectives of water management

Erismann, Julie 28 February 2014 (has links)
Le lac Alaotra est la plus grande étendue d’eau douce de Madagascar et les vastes plaines qui l’entourent ont tout naturellement attiré les convoitises des différents pouvoirs en place au cours de l’histoire, de sa colonisation. Essentiellement tournée vers la riziculture, cette région a bénéficié de nombreux aménagements qui ont transformé le paysage et le rapport des hommes à leur environnement. La combinaison au fil du temps des savoirs et savoir-faire paysans, techniciens, et l’intérêt des chercheurs en font aujourd’hui « le grenier à riz » de Madagascar. C’est autour de la maîtrise de l’eau, ressource essentielle dans ce pays d’économie rurale, que s’organise cette thèse de Géographie. À travers l’étude des vallées du sud-est de l’Alaotra, nous nous intéressons ici à montrer dans quelle mesure les aménagements hydro-agricoles permettent d’envisager un meilleur développement agricole et territorial et comment, dans un contexte de décentralisation, le contrôle et l’appropriation des ressources naturelles par les acteurs locaux peuvent engendrer des dynamiques et des modalités de gestion renouvelées de leur environnement. / Alaotra lake is the biggest body of fresh water in Madagascar and the vast plains surrounding it, have naturally become highly coveted by the various authorities over the course of it’s history and its colonization. Primarily based on rice cultivation, this region has benefited from numerous rural planning projects. As a result, the landscape as well as the relationship between the people and their land has been transformed. Over time, the combination of knowledges and know-how farmers, technicians and the research interest in this area, have made it Madagascar’s most significant rice granary. This geography thesis is structured around water management, an essential resource in a country based on rural economies. Through the study of the southeastern valleys, we will focus on showing the extent to which the hydro-agricultural planning allows us to consider better agricultural and territorial development and how, in a context of decentralization, the control and the appropriation of natural resources by local actors can lead to renewed management dynamics and procedures in their environment. / Ny farihy Alaotra no fihebanandranomandry lehibe indrindra ao Madagasikara , ary ny tany lemaka midadasika manodidina azy no nanitona ny fitsiriritan’ireo manampahefana nifandimby tao amin’ny tantaran’ny fiorenamponenana.Ny fambolem-bary no votoatim-piainana ao amin’io faritany io , ary fanajariana marobe no efa nanova tanteraka ny endrikin’ny tany sy ny fonenana eo . Ny fandrindrana ny fahalalàna sy fahaiza-miasan’ny tantsaha, ny mahay taozavatra , sy ny finiavan’ny mpikarodalana no nahatonga azy ho « lavabarin’i Madagasikara ». Manodidina ny fanafolahana ny rano , andry ijoroan’ny toekarenan’ny antsaha , no namolavolàna ity tandro-kevitra fandinihantany ity. Avy eo amin’ny fikatsahana natao tao amin’ireo lohasaha ao Atsimo-atsinanan’Alaotra no niaingan’ny sainay hampiseho fa ny fanajariana ny rano sy asatany no hahafahana mihevitra ny fivoaram-bokatra amin’ny voly sy ny faritany ; ary koa ao anatin’ny fitsinjarampitondrana , dia hahitàna fa ny fandinihana sy ny fandraisana an-tanana ireo loharanon-karena velona ataon’ny mpiasa eo antoerana no mety hiteraka fampandrosoana sy fivaozan’ny fitantanana ny toe-ponenana manotolo.
168

Sustainable Agri-food Production and Consumption

James D. Chapa (5930576) 11 June 2019 (has links)
Agri-food production is necessary to sustain the growing global population, but it adversely impacts the environment in various ways, including climate change, eutrophication, acidification, land and water uses, and loss of biodiversity, etc. These environmental impacts can also negatively affect human health, which could in theory outweigh the health benefits of nutritious food. While better agricultural practices need to be developed and applied to minimize the environmental burdens associated with the production chains, consumers are expected to implement more sustainable lifestyles and eat more environment-friendly foods. Life Cycle Assessment (LCA) is an analytical tool to evaluate the sustainability of a product by examining all the resources used and emissions generated during its life cycle. The first part of this work focused on the upstream production. An LCA of organic blueberry production was conducted to evaluate the trade-off between seasonal and local options and answer the question of whether imported fresh or domestic frozen blueberries are more sustainable. Fresh blueberries from Chile showed superior environmental performance within 2-week storage, due to lower electricity use associated with refrigeration and higher farming yield. Furthermore, length of storage and transportation distance were also found important; if farming yields are comparable, consumption of locally produced, fresh blueberries will be a better choice because of less energy use and shorter transportation distance. The second part of this work targeted at the downstream consumption and aimed to reduce the U.S. environmental footprint through changing adult eating habits. Supplemental functional units were applied in the LCA to incorporate the functions of food to provide nutrition and satiety. With controlled caloric intake, vegetarian diets were found overall more sustainable. However, large possible variations in the environmental impacts of the compared diets were observed due to wide range of nutritional quality of selected foods. Animal products, including meat and dairy especially, and discretionary foods were identified as hotspots in the American diet, that is, reducing the consumption of these foods or deliberately choosing more sustainable alternatives within the same food categories, like chicken and low-fat milk, can significantly improve the sustainability of current American dietary patterns. <br>
169

Arbuscular mycorrhizal fungi: crop management systems alter community structure and affect soybean growth and tolerance to water stress

Lisseth Zubieta (5930507) 03 January 2019 (has links)
<p>Arbuscular mycorrhizal fungi (AMF) are best known for their potential to help plants acquire nutrients, especially phosphorous. These microbes improve soil health by promoting soil aggregation and carbon sequestration, and further benefit plants by helping them withstand biotic and abiotic stress. Currently, there are 200 recognized species of AMF within the phylum Glomeromycota. Recent studies indicate that individual AMF species differ in the benefits they provide, with some even acting as parasites. Moreover, AMF community composition can be altered by soil and crop management practices, but the effect of these changes on the benefits conferred by AMF are still not well understood. Consequently, the goal of this study was to determine how two widely used crop management systems can alter the composition of AMF species, and affect the potential for these communities to promote the productivity and drought tolerance. To accomplish this goal, we collected AMF inoculum from a long-term crop systems trial comparing organic and conventional management for use in greenhouse trials where we subjected plants to drought. We collected AMF inoculum during mid-summer when differences between the two management systems were likely cause larger effects on AMF communities, and again in autumn after harvest to see if differences in AMF communities would persist. We determined AMF species composition using next generation sequencing. Results of this study confirm that soil-building practices commonly used in organic farming systems can improve soil health and increase the productivity of food-grade soybeans. They also demonstrate that AMF communities in Indiana croplands are highly diverse, and some of these taxa can improve soybean growth and help plants tolerate water stress. Although the overall diversity of AMF communities did not differ between the organic and conventional management systems in mid-summer, individual AMF taxa did differ between the systems, which were likely responsible for the greater tolerance to water stress observed when plants were amended with inoculum from the organic system. AMF communities present during autumn were significantly different between the two crop management systems, but did not result in differences in drought tolerance of soybeans, indicating that the loss of key AMF taxa in the organic system from the first relative to the second experiment was likely responsible. Finally, plants grown using inoculum from both crop management systems in autumn had greater tolerance to water stress than plants that received a AMF commercial inoculum. This provides further evidence that individual AMF species vary in the benefits they provide, and that the presence of a diverse consortium of AMF species is needed to optimize plant health and productivity in agricultural systems. Agricultural producers should consider incorporating soil-building practices that are commonly used in organic farming systems such as planting winter cover crops, to improve the health of their soil and enhance the productivity of their crops. <b></b></p> <br>
170

An exploration of sustainability problems in community gardens with specific reference to Pfukani Community Garden Project in Greater Giyani Municipality of the Limpopo Province

Checha, Samuel Mafemani January 2003 (has links)
Thesis (M. Dev.) -- University of Limpopo, 2003 / Refer to document

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