Thesis (MScAgric)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The objective of this study was to consider whether smallholders operate within homogenous or differentiated farming systems i.e. a similar “‘one type”’ system or a system that could be described as a smallholder typology consisting of a number of farming types. The enquiry firstly described and analysed farm diversity and then developed risk attitude profiles of smallholder farmers in the Stellenbosch local municipal area in the Western Cape province of South Africa. The problem statements, directing this study is that there is a general misconception that smallholders are all “‘the same’” and that they all operate within one ‘“representative farming model”’; and that the majority of smallholders are risk averse. These views also argue that all smallholder farmers are not primarily directed at profit objectives, but that social considerations are most relevant and that different social orientations are shaping farming systems. These views are investigated in this study and the hypotheses directing this analysis is that smallholders in the study area are not a homogenous group; rather types within a broader farming typology, with different orientations and objectives and with different risk attitude profiles. The study originated as part of an international collaborative investigation – the South African Agrarian Diagnoses project, a joint research project of the Agro Paris Tech/Agence Francaise de Development, the Standard Bank Centre for Agribusiness Development and Leadership, Stellenbosch University and the University of Pretoria in to farmer diversity and farmer typologies in South Africa. This investigation looked at smallholder farming in different agrogeographical areas in South Africa, with this particular study focussing on potential smallholder farmer diversity in the Stellenbosch local municipal area. The Stellenbosch local municipality and Western Cape Department of Agriculture provided logistical support, information to this investigation and participated in focus group sessions. Smallholder activity in this study was defined to include both small scale farming activities and the mobilisation of smallholders/farm workers in so-called ‘“farm worker equity schemes’” – a type not included in the other regions. Data was collected from eight smallholders’ farming communities and the four different farm workers’ equity share schemes through surveys and interviews. The following towns and hamlets: Franschhoek, Kylemore, Lanquedoc (Herbal View and Spier Corridor), Pniel, Jamestown, Raithby, Lynedoch and Koelenhof; and four farm workers’ equity share schemes were: Swartrivier vineyard project, Koopmanskloof vineyard project, Enaleni Trust and Poker Hill vineyard project. Personal interviews and focus group discussions were conducted and cluster analysis was used for the diversity (typology) analysis and the Likert scale was employed to measure risk attitude profiles. A non-probability sampling approach was used to select a sample size of 49 respondents. The reason for using non-probability sampling technique was that when one wants to do the diversity analysis, one must try to include many respondents in the sample and the farmers that are included must be representative of the population from which they are selected. The variables selected as determinants of farm diversity included information about: demographics and households, land ownership and occupation, farming activities, farming objectives, agricultural inputs, labour, equipment, farming constraints, access to markets, financial support services, educational and training services, extension services and reasons for quitting farming activities. From this, different farming types and typologies were identified, described and structured. Preference indications for different risk management strategies were then used to measure and describe the risk attitudes of different types of smallholder farmers using the Likert risk attitudinal scale. The results and findings confirmed the study hypotheses relating to diversity in smallholder farming in the target area, namely that smallholders in this geographical area are not a homogenous group and rejects the stated hypotheses that most smallholder farmers are risk averse. A Stellenbosch smallholder typology, with six different farming types were established viz: type 1 – farmland-occupying but non-farming households (10.2% of the sample), type 2 – pensioner – livestock farmers (16.3% of the sample), type 3 – part-time cattle farmers (14.3% of the sample), type 4 – commercial equity share farmers (16.3% of the sample), type 5 – retirement planning crop producers (20.4% of the sample), and type 6 – commercial crop producers (22.5% of the sample). With regard to risk profiles, risk attitudes varied between these types and also within each type, hence risk attitudes for smallholders are also not found to be similar. The results revealed that those smallholder farmers moving on a development path towards commercial agriculture (types 4, 5 and 6) were risk preferring; less commercially orientated farm types (types 1, 2 and 3), showed risk averse and risk neutral orientations. The risk profile percentages of farmers interviewed were 43.2%, 34.1% and 22.7%, respectively for risk preferring, risk neutral and risk averse; this finding rejects the stated hypotheses. From these results, a number of issues, relevant to development support programmes, were proposed for further agricultural economic research. The most important of these are related to: appropriate development support strategies related to farm types and the potential development paths for each type; and the structuring of appropriate ‘“risk management instruments”’ for each type, in particular to support smallholder farmers; with a development trajectory towards commercial farming, i.e. to support emerging commercial farmers – an important category of farming listed in current government policy and in the National Development Plan. / AFRIKAANSE OPSOMMING: Die doelwit van hierdie studie was om ondersoek in te stel na die tipe kleinboere-stelsel (smallholder farming systems) wat voorkom in die Stellenbosch munisipale gebied in die WesKaap provinsie van Suid Afrika en die eenvormigheid al dan nie daarvan te ontleed. Eerstens is plaasdiversiteit ondersoek en ontleed; en daarna die risikohoudings van sondagie kleinboere. Die ontledings is dan gebruik om uitspraak te gee oor die eenvormigheid of diversiteit van kleinboerestelsels in die geogafiese gebied. Die probleemstelling wat hierdie studie gerig het, was dat daar ’n algehele wanbegrip mag bestaan dat kleinboere almal “dieselfde” is, of binne n ‘“eenvormige verteenwoordigende boerderymodel”’ funksioneer; en dat, gekoppel hieraan, die meerderheid kleinboere risikoafkerig is. Hierdie sienings hou ook voor dat alle kleinboere nie noodwendig op winsdoelwitte fokus nie, maar dat maatskaplike oorwegings ook relevant is en dat verskillende oriëntasies boerderystelsels vorm. Hierdie sienings word in hierdie studie ondersoek en die hipotese wat die analise rig, is dat die kleinboere in die studie nie ’n eenvormige of homogene groep is nie, eerder verskillende soorte/tipes kleinboere met verskillende oriëntasies en doelwitte en dus ook met verskillende risikohoudings. Die studie het sy oorsprong as deel van ’n internasionale samewerkende ondersoek – die South African Agrarian Diagnoses-projek van die Agro Paris Tech/Agence Francaise de Development, die Standard Bank Sentrum vir Agribesigheidsontwikkeling en Leierskap, Universiteit van Stellenbosch endie Universiteit van Pretoria oor die diversiteit en tipologieë van kleinboere in Suid Afrika. Hierdie ondersoek het gekyk na verskillende agro-geologiese gebiede in SuidAfrika, met hierdie studie wat gefokus het op die potensiële diversiteit van boere in die Stellenbosse plaaslike munisipale gebied. Die Stellenbosche Munisipaliteit en Departement van Landbou in die Wes Kaap het ondersteunend gestaan met logistiek en deelname aan fokusgroep gesprekke. Kleinboeraktiwiteit in hierdie studie is gedefinieer om beide kleinskaalse boerderyaktiwiteite op klein grond persele, as ook die mobilisering van kleinboere/plaaswerkers in sogenaamde gedeelde boerdery - eienaarskapskemas in te sluit – n unieke tipe wat nie in die ander streke ondersoek is nie.. Data is vanuit agt kleinboergemeenskappe en die vier verskillende gedeelde eienaarskapskemas vir plaaswerkers deur middel van opnames en onderhoude bekom. Die boerderygemeenskappe was in die volgende dorpe en klein dorpies gevestig: Franschhoek, Kylemore, Lanquedoc (Herbal View en Spier Corridor), Pniel, Jamestown, Raithby, Lynedoch en Koelenhof; en die vier gedeelde eienaarskapskemas vir plaaswerkers was: die Swartrivier wingerdprojek, die Koopmanskloof wingerdprojek, Enaleni Trust en die Poker Hill wingerdprojek. Persoonlike onderhoude en fokusgroepbesprekings is gehou en cluster analise is gebruik vir die diversiteit (tipologie) analise en die Likertskaal is gebruik risiko houding profiele te meet. 'N niewaarskynlikheidsteekproefneming benadering is gebruik om 'n steekproefgrootte van 49 respondente te kies. Die rede vir die gebruik van nie-waarskynlikheidsteekproefneming tegniek was dat wanneer 'n mens die diversiteit ontleding te doen, moet 'n mens probeer om soveel respondente in die monster en die boere wat ingesluit is, moet verteenwoordigend van die bevolking waaruit hulle gekies word om te sluit. Onderhoude is gedoen met sulke kleinboere en trosanalise is gebruik vir die analise van diversiteit (tipologie), en die Likert-skaal is gebruik om risikohoudingsprofiele te meet. Die veranderlikes wat as determinante van plaasdiversiteit gekies is, het inligting oor demografie en huishoudings, grondeienaarskap en -besetting, boerderyaktiwiteite, boerderydoelwitte, landboukundige insette, arbeid, toerusting, boerderybeperkings, marktoegang, finansiële ondersteuningsdienste, opvoedkundige en opleidingsdienste, uitbreidingsdienste en redes hoekom boerdery laat vaar is, ingesluit. Hieruit is verskillende boerderytipes geïdentifiseer en gekonstrueer. Voorkeure opsies vir verskillende risikobestuurstrategieë is gebruik om die risikohoudings van die deur middel van die Likert risikohoudingskaal te meet. Die resultate van hierdie studie het die hipotese oor die aanwesigheid van diversiteit bevestig, naamlik dat kleinboere in hierdie geografiese gebied nie ’n homogene groep is nie n verwerp die gestelde hipoteses dat die meeste kleinboere is risiko-sku. ’n Stellenbosch-tipologie, bestaande uit ses verskillende boerderytipes, is vasgestel: tipe 1 – huishoudings wat nie boer nie maar wat op landbougrond woon (10.2% van die monster), tipe 2 – pensioenaris-veeboere (16.3% van die monster), tipe 3 – deeltydse veeboere (14.3% van die monster), tipe 4 – kommersiële gedeelde eienaarskapskema boere (16.3% van die monster), tipe 5 – gewasprodusente wat aftrede beplan (20.4% van die monster), en tipe 6 – kommersiële gewasprodusente (22.5% van die monster). Met betrekking tot risikoprofiele het risikohoudings tussen die tipes en ook binne elke tipe gewissel, dus is die risikohoudings van kleinboere ook nie gevind om dieselfde te wees nie. Die resultate toon dat kleinboere wat in die rigting van kommersiële landbou beweeg (tipes 4, 5 en 6) risiko-voorkeurend is; daarenteen het minder kommersieel gerigte plaastipes (tipes 1, 2 en 3)risiko-afkerige en risiko-neutrale instellings getoon. In die geheel was die persentasies 43,2%, 34.1% en 22.7% vir risiko-voorkeurend, risiko-neutraal en risiko-afkerig onderskeidelik, wat ook die diversiteitshipotese ondersteun. Vanuit hierdie bevindings word ’n aantal kwessies wat relevant is vir ontwikkelingsondersteuningsprogramme vir kleinboere op verskillende ontwikkelingstrajekte, voorgestel vie verder elandbou ekonomiese navorsing. Die belangrikste hiervan hou verband met die aangewese ontwikkelingstrajekte per kleinboer tipe en daarmeegepaardgaande gepaste “risikobestuurinstrumente” – veral vir die ondersteuning van kleinboere met ’n ontwikkelingstrajek na kommersiële boerdery, m.a.w. opkomende kommersiële boere – ’n belangrike boerderykategorie wat in huidige regeringsbeleid en in die Nasionale Ontwikkelingsplan geprioritiseer word.

The objective of this research was to determine the effects of conventional inputs on soil chemical and biological properties compared to organic systems in a four year vegetable rotation. Tillage and cover crops were the same in all treatments to avoid confounding factors often present in similar research. Additional experiments investigated plant gene expression in organic and conventional management systems and in soils with decreased microbial diversity. Experimental plots were prepared in the spring of 2004; four replications of three management treatments, organic, low-input and conventional, were arranged in a randomized complete block design. The rotation consisted of edamame soybean, sweet corn, fallow (pastured poultry in organic plots), and potatoes. Soil samples were taken in the spring and fall of each year, along with data for pest damage, weed control, yield and quality. Soil samples were analyzed for enzyme activity (maximum activity under substrate saturation) and basic soil chemical properties. Treatments were compared over time using 2-Way ANOVA. Multiplex terminal-restriction fragment length polymorphism (M-TRFLP) profiles of the soil microbial community were compared using Multiple Response Permutation Procedures (MRPP). Multi-way ANOVA detected significant treatment effects over time in total carbon, nitrogen, Mehlich III K, Exchangeable K and exchangeable Na (p=0.05). Many significant changes in soil properties over time could not be attributed to treatment effects. All treatments produced similar yields, indicating that successful organic production of these vegetables is possible in Kentucky. Input costs for organic were 37% higher than conventional, due to the cost of organic fertilizer. The organic system required nearly 50% more labor hours than conventional or low-input. The low-input system was the most cost effective, with 58% less input expenses than the conventional system. Microarray analysis of approximately 37,500 Glycine max transcripts did not show significant differences in the gene expression between plants grown organically and conventionally, in plots with significant soil chemical and microbial differences. An experiment in progress is investigating changes in plant gene expression using real time RT-PCR in tomatoes grown in autoclaved soil and native field soil.

O filo Actinobacteria é, atualmente, considerado um dos maiores filos pertencentes ao domínio Bacteria. Este filo pode representar até 30% da comunidade microbiana do solo. Os organismos do filo Actinobacteria tem sido caracterizados como produtores de antibiótico e degradadores de substâncias complexas como os alcanos, presente em diversas substâncias encontradas em plantas. Em relação à degradação dos alcanos já tem sido comprovado que o gene alkB (alcano hidroxilase), presente no filo Actinobacteria, está relacionado a sua degradação. Porém, as comunidades de tais organismos podem ser alteradas por mudanças no uso do solo, que no Brasil ocorrem extensivamente devido a implantação de monoculturas. A cultura de cana-de-açúcar, que vem se expandido anualmente, se mostra como uma das culturas que podem alterar a microbiota do solo. Os diferentes sistemas de colheita de cana-de-açúcar, com e sem a queima da palhada, podem alterar a microbiota do solo. Assim, considerando o papel do filo Actinobacteria na ciclagem de matéria orgânica, além da sua importância biotecnológica, este trabalho avaliou como os diferentes sistemas de colheita da cana-de-açúcar influenciam as comunidades rizosféricas de Actinobacteria e de bactérias oxidadoras de alcano, sob condições controladas em casa de vegetação, utilizando técnicas moleculares para quantificar (qPCR), análisar a estrutura (T-RFLP) e a diversidade da comunidade (sequenciamento de metagenoma). Para isso o solos coletado de áreas de plantação de cana-de-açúcar com os manejos de colheita com e sem queima da palhada, foram utilizados em experimento de mesocosmos composto por vasos com planta, de onde foi coletado solo rizosférico, e vaso sem planta, de onde foi coletado solo controle. A quantificação dos gene 16S rRNA de Actinobacteria e do gene alkB não mostraram diferenças estatística nas comparações dos solos controles de cana-de-açúcar com e sem queima, e na comparação entre os solos rizosférico e controle de cada tipo de manejo de colheita. A análise dos Fragmentos Terminais de Restrição (TRFs) dos solos controle dos diferentes sistemas de colheita, mostraram uma separação da comunidade bacteriana presente no solo, o mesmo ocorreu nas comparações entre os solos rizosférico e controle de diferentes manejos de colheita. Porém, quando se observa a estrutura taxonômica da comunidade bacteriana nota-se que os filos Proteobacteria, Actinobacteria, Firmicutes e Acidobacteria são predominantes nos diferentes solos amostrados, as diferenças estatísticas entre os solos controle e rizosférico de cada tratamento se apresentam a partir da análises das famílias bacterianas presentes nos solos. Para o gene alkB, as sequências encontratas nos diferentes solos pertencem aos dois filos mais abundantes nos solos, os filo Proteobacteria e Actinobacteria, porém algumas sequências pertencem a bacterias não identificadas. Assim, conclui-se que as mudanças na estrutura da comunidade bacteriana presente em solo com monocultura da cana-de-açúcar são perceptíveis a partr da análises de grupos filogenéticos mais baixo e que a comunidade de bactéria degradadoras de alcanos são pertencentes, principalmente, os filos Actinobacteria e Proteobacteria, porém ainda é necessário mais estudos para a classificação das bactérias não identificadas / The phylum Actinobacteria is currently considered one of the major phyla belonging to the domain Bacteria. This phylum can represent up to 30% of the soil microbial community. The organisms of the phylum Actinobacteria has been characterized as antibiotic producers and degraders of complex substances such as alkanes, present in several substances found in plants. Regarding the degradation of alkanes it has already been proven that alkB gene (alkane hydroxylase), present in the phylum Actinobacteria, is related to its degradation. But the communities of such organisms can be altered by changes in land use, which in Brazil occur extensively due to implementation of monocultures. The cultivation of sugarcane, which has been expanded annually, appears as one of the crops that can alter the soil microbiota. The different sugarcane harvest systems, with and without straw burning, can alter the soil microbiota.Thus, considering the role of the phylum Actinobacteria in the cycling of organic matter, in addition to their biotechnological importance, this study evaluated how different harvest systems of sugarcane influence rhizospheric communities of Actinobacteria and alkane-oxidizing bacteria under controlled conditions in a greenhouse, using molecular techniques to quantify (qPCR), analyse the structure (T-RFLP) and diversity of the community (metagenomic sequencing). For this, the soil collected from sugarcane fields with harvest managements with and without burning the straw, was used in a mesocosms experiment composed of pots with a sugarcane plant, from where rhizosphere soil was collected, and without plant, from where control soil was collected. The quantification of Actinobacteria 16S rRNA gene and alkB gene showed no statistical differences in the comparison of sugarcane controls soil with and without burning, and in the comparison between rhizosphere and control soil of each type of crop management. Terminal Restriction Fragments (TRF) analysis of control soils of different harvesting systems showed a separation of the bacterial community present in the soil, the same occurred in the comparison between rhizosphere and control soils of different harvesting systems. However, when observing the taxonomic structure of the bacterial community it is noted that that the phyla Proteobacteria, Actinobacteria, Firmicutes and Acidobacteria are predominant in different sampled soils, the statistical differences between the control and rhizosphere soil of each treatment are presented from the analysis of bacterial families present in the soil. For alkB gene, the sequences found in different soils belong to the two most abundant phyla in the soil, the phylum Proteobacteria and Actinobacteria, but some sequences belong to unidentified bacteria.Thus, it is concluded that the changes in the structure of the bacterial community present in soil with monoculture of sugarcane are apparent from the analysis of lower phylogenetic groups and the alkane-degrading bacterial communities belong mainly to the phyla Actinobacteria and Proteobacteria, however it is still needed further studies for the classification of unidentified bacteria

A aplicação de sistemas inteligentes na área agrícola têm gerado grandes avanços na automação de alguns processos da cadeia produtiva, o que acarreta na redução de custos logísticos. Com o intuito de apoiar o desenvolvimento desses sistemas produtivos é proposto um sistema de visão usando tecnologia de imagens térmicas e lógica difusa para a estimativa da quantidade de frutos em cultura citros. Inicialmente é apresentada uma revisão bibliográfica dos diferentes sistemas usados para o reconhecimento de frutos e das diferentes aplicações da termografia em sistemas agrícolas. O algoritmo de processamento de imagens utilizado no desenvolvimento do projeto; usa as métricas dos parâmetros fuzzy para a melhora do contraste e para a segmentação da imagem. Já para a contagem dos frutos foi usada a Transformada de Hough Circular (THC). Com o intuito de validar o algoritmo proposto foi criado um banco de fotos, adquiridas num talhão de laranjeira doce Citrus (L.) Osbeck. Os testes feitos com o algoritmo indicam que a variação de temperatura entre o galho da arvore e o fruto não é muito alta, o que dificulta o processo de segmentação da imagem através dessa diferença, incrementando a quantidade de falsos positivos no algoritmo de contagem dos frutos. O reconhecimento de frutos isolados com o algoritmo proposto apresentou uma precisão total de 90,5% e para frutos agrupados a precisão foi de 81,3%. / In agriculture, intelligent systems and applications have generated great advances in automating some of the processes in the production chain. In order to improve the efficiency of those systems is proposed a vision system to estimate the amount of fruits in sweet orange trees. This work presents a system that relies on thermal images and fuzzy logic. A bibliographical review has been done to analyze the state-of-the-art of the different systems used in fruit recognition, and also the different applications of thermography in agricultural systems. The algorithm developed for this project uses the metrics of the fuzzines parameter to the contrast improvement and segmentation of the image, for the counting algorithm the Hough transform was used. In order to validate the proposed algorithm was created a bank of images of sweet orange Citrus (L.) Osbeck acquired in the Maringá Farm. The tests with the algorithm Indicated that the variation of the tree branch temperature and the fruit is not very high. Which makes the process of image segmentation using this differentiates, This Increases the amount of false positives in the fruit counting algorithm. Recognition of fruits isolated with the proposed algorithm present an overall accuracy of 90.5% and grouped fruits, the accuracy was 81.3%. The experiments show the need for a more suitable hardware to have a better recognition of small temperature changes in the image.

Este trabalho traz como eixo central o entendimento das diferentes formas de intervenção do Estado por meio de políticas públicas de reordenamento agrário e sua influência no processo de obtenção e utilização da renda agrícola. Desta forma, entendendo até quando as políticas públicas, especificamente aquelas destinadas ao reordenamento agrário, devem observar a ordem local, visto que esta ordem é construída de maneira a atender as necessidades destas sociedades, trazendo como hipótese de encaminhamento e solução a diferenciação das políticas atendendo as peculiaridades sociais. Tem como objetivo geral compreender como as diferentes políticas públicas destinadas ao desenvolvimento rural, especificamente as políticas de reordenamento agrário tem influenciado o processo de geração de renda (agrícola e de autoconsumo) em contextos culturais e de organização produtiva diversificada em três comunidades rurais do município de Presidente Juscelino/MA, sendo elas: Boa Vista dos Pinhos, Juçaral dos Pretos e Folhal. A metodologia utilizada para a realização deste trabalho foi inicialmente o levantamento histórico dos sistemas agrários, visando a compreensão da estrutura agrária e social em questão, posteriormente em outro momento do trabalho foram aplicados questionários semiestruturados com o objetivo de obter dados quanti qualitativos sobre o processo de geração da renda monetária, auto consumo, sendo encontrado nesse momento uma nova forma de ganhos conseguidos por meio da organização e da manutenção da estrutura social. Levando-se em conta referenciais antropológicos efetuou-se uma leitura do processo por meio da produção de farinha como eixo norteador e gerador das condições necessárias para produzir desenvolvimento. / This work has as central axis to understanding the different forms of State intervention, through public policies of agrarian reordering and its influence in the process of obtaining and using agricultural income. In this way, understanding even when public policies, specifically those aimed at agrarian reordering, must obey the local order. Since this order is constructed in such way as to meet the needs of these societies, bringing as a hypothesis of routing and solution the differentiation of the Policies taking into account social peculiarities. With the general objective of understanding how the different public policies aimed at rural development, specifically agrarian reordering policies, have influenced the process of income generation (agricultural and self-consumption) in cultural contexts and of diverse productive organization in three rural communities of the municipality of Presidente Juscelino/MA, being Boa Vista dos Pinhos, Juçaral dos Pretos and Folhal. The methodology used to carry out this work was initially the historical survey of the agrarian systems, with a view to understanding the agrarian and social structure in question, Later in another moment of the work, semistructured questionnaires were applied with the objective to obtaining qualitative and quantitative data on the process of generating monetary income. Self consumption, being found in this moment a new form of gains obtained through the organization and maintenance of the formal structure. Taking into account anthropological references was made reading of the process through the production of flour as a guiding axis and generator of the necessary conditions to generate development.

O filo Actinobacteria é, atualmente, considerado um dos maiores filos pertencentes ao domínio Bacteria. Este filo pode representar até 30% da comunidade microbiana do solo. Os organismos do filo Actinobacteria tem sido caracterizados como produtores de antibiótico e degradadores de substâncias complexas como os alcanos, presente em diversas substâncias encontradas em plantas. Em relação à degradação dos alcanos já tem sido comprovado que o gene alkB (alcano hidroxilase), presente no filo Actinobacteria, está relacionado a sua degradação. Porém, as comunidades de tais organismos podem ser alteradas por mudanças no uso do solo, que no Brasil ocorrem extensivamente devido a implantação de monoculturas. A cultura de cana-de-açúcar, que vem se expandido anualmente, se mostra como uma das culturas que podem alterar a microbiota do solo. Os diferentes sistemas de colheita de cana-de-açúcar, com e sem a queima da palhada, podem alterar a microbiota do solo. Assim, considerando o papel do filo Actinobacteria na ciclagem de matéria orgânica, além da sua importância biotecnológica, este trabalho avaliou como os diferentes sistemas de colheita da cana-de-açúcar influenciam as comunidades rizosféricas de Actinobacteria e de bactérias oxidadoras de alcano, sob condições controladas em casa de vegetação, utilizando técnicas moleculares para quantificar (qPCR), análisar a estrutura (T-RFLP) e a diversidade da comunidade (sequenciamento de metagenoma). Para isso o solos coletado de áreas de plantação de cana-de-açúcar com os manejos de colheita com e sem queima da palhada, foram utilizados em experimento de mesocosmos composto por vasos com planta, de onde foi coletado solo rizosférico, e vaso sem planta, de onde foi coletado solo controle. A quantificação dos gene 16S rRNA de Actinobacteria e do gene alkB não mostraram diferenças estatística nas comparações dos solos controles de cana-de-açúcar com e sem queima, e na comparação entre os solos rizosférico e controle de cada tipo de manejo de colheita. A análise dos Fragmentos Terminais de Restrição (TRFs) dos solos controle dos diferentes sistemas de colheita, mostraram uma separação da comunidade bacteriana presente no solo, o mesmo ocorreu nas comparações entre os solos rizosférico e controle de diferentes manejos de colheita. Porém, quando se observa a estrutura taxonômica da comunidade bacteriana nota-se que os filos Proteobacteria, Actinobacteria, Firmicutes e Acidobacteria são predominantes nos diferentes solos amostrados, as diferenças estatísticas entre os solos controle e rizosférico de cada tratamento se apresentam a partir da análises das famílias bacterianas presentes nos solos. Para o gene alkB, as sequências encontratas nos diferentes solos pertencem aos dois filos mais abundantes nos solos, os filo Proteobacteria e Actinobacteria, porém algumas sequências pertencem a bacterias não identificadas. Assim, conclui-se que as mudanças na estrutura da comunidade bacteriana presente em solo com monocultura da cana-de-açúcar são perceptíveis a partr da análises de grupos filogenéticos mais baixo e que a comunidade de bactéria degradadoras de alcanos são pertencentes, principalmente, os filos Actinobacteria e Proteobacteria, porém ainda é necessário mais estudos para a classificação das bactérias não identificadas / The phylum Actinobacteria is currently considered one of the major phyla belonging to the domain Bacteria. This phylum can represent up to 30% of the soil microbial community. The organisms of the phylum Actinobacteria has been characterized as antibiotic producers and degraders of complex substances such as alkanes, present in several substances found in plants. Regarding the degradation of alkanes it has already been proven that alkB gene (alkane hydroxylase), present in the phylum Actinobacteria, is related to its degradation. But the communities of such organisms can be altered by changes in land use, which in Brazil occur extensively due to implementation of monocultures. The cultivation of sugarcane, which has been expanded annually, appears as one of the crops that can alter the soil microbiota. The different sugarcane harvest systems, with and without straw burning, can alter the soil microbiota.Thus, considering the role of the phylum Actinobacteria in the cycling of organic matter, in addition to their biotechnological importance, this study evaluated how different harvest systems of sugarcane influence rhizospheric communities of Actinobacteria and alkane-oxidizing bacteria under controlled conditions in a greenhouse, using molecular techniques to quantify (qPCR), analyse the structure (T-RFLP) and diversity of the community (metagenomic sequencing). For this, the soil collected from sugarcane fields with harvest managements with and without burning the straw, was used in a mesocosms experiment composed of pots with a sugarcane plant, from where rhizosphere soil was collected, and without plant, from where control soil was collected. The quantification of Actinobacteria 16S rRNA gene and alkB gene showed no statistical differences in the comparison of sugarcane controls soil with and without burning, and in the comparison between rhizosphere and control soil of each type of crop management. Terminal Restriction Fragments (TRF) analysis of control soils of different harvesting systems showed a separation of the bacterial community present in the soil, the same occurred in the comparison between rhizosphere and control soils of different harvesting systems. However, when observing the taxonomic structure of the bacterial community it is noted that that the phyla Proteobacteria, Actinobacteria, Firmicutes and Acidobacteria are predominant in different sampled soils, the statistical differences between the control and rhizosphere soil of each treatment are presented from the analysis of bacterial families present in the soil. For alkB gene, the sequences found in different soils belong to the two most abundant phyla in the soil, the phylum Proteobacteria and Actinobacteria, but some sequences belong to unidentified bacteria.Thus, it is concluded that the changes in the structure of the bacterial community present in soil with monoculture of sugarcane are apparent from the analysis of lower phylogenetic groups and the alkane-degrading bacterial communities belong mainly to the phyla Actinobacteria and Proteobacteria, however it is still needed further studies for the classification of unidentified bacteria

[Truncated abstract] The initial success of the Green Revolution notwithstanding, the ability of our planet to produce sufficient food to support its growing population is causing growing concern. Indonesia, like many other countries, cannot produce sufficient rice to feed its people. This creates an imperative to import rice that Indonesia wishes to overcome. In addition, agricultural intensification has created ecological contamination from overuse and the mismanagement of chemical inputs. These problems threaten the sustainability of agricultural lands and Indonesia's ability to support national food selfsufficiency. The extension of agricultural lands is one alternative that has been implemented by the Indonesian government for more than two decades. Families from the crowded islands of Java and Bali have been translocated to the outer islands of Kalimantan, Sulawesi, and Papua. In South Kalimantan, the tidal swampland areas are one of the resettlement destinations; which are usually reclaimed for the purpose of increasing rice production. However, the difference between the natural characteristics, socialeconomics, language, and culture in South Kalimantan, compared with the homelands of the transmigrant farmers, has the potential to adversely affect the farming activities of both the transmigrant and the local indigenous farmers. This in turn might affect the sustainability of the tidal wetlands for agricultural production. It may also damage the ecological integrity of the coastal environment ... The research findings indicate that farming practices by the groups differed significantly. Similarly, there was a significant difference between the cultivation of traditional rice varieties and the HYV. Farming practices performed by the indigenous local farmers, who have lived in the swamplands for centuries, were more ecologically sustainable than those of their transmigrant counterparts in both of the tidal swamplands being assessed. Likewise, traditional (indigenous) rice variety cultivation appears to be more sustainable than the HYVs. Among the socio-economic and agronomic influences of the farming practices selected for statistical analysis, only the non-formal education variable had a significant impact on the sustainability index. Tidal swampland Type B has lower yields than Type A, but in both swampland types, indigenous farmers produce higher yields than the transmigrant farmers, while the HYV has a higher yield over the traditional one. Indigenous farmers received higher financial returns per ha compared to the transmigrant returns in tidal swampland Type A and Type B. The higher yields produced by the HYVs are not accompanied by a higher financial return per ha compared to the traditional variety. The conclusions of this research are that not only are indigenous farming practices more sustainable but that indigenous farmers achieve a higher overall output and higher returns per ha from their farming activities. Future research should be formulated to further investigate the implications for both increasing rice production and sustainability by extending the use of indigenous farming systems. The sustainability index developed in this research should be investigated for adaptation in other areas of Indonesia and possibly by other farming areas internationally.

In the semi - arid Mediterranean - type environments of southern Australia, soil and water resources largely determine crop productivity and ultimately the sustainability of farming systems within the region. The development of sustainable farming systems is a constantly evolving process, of which cropping sequences ( rotations ) are an essential component. This thesis focused on two important soil resources, soil water and nitrogen, and studied the effects of different crop sequences on the dynamic of these resources within current farming systems practiced on the upper Eyre Peninsula of South Australia. The hypothesis tested was that : continuous cropping may alter N dynamics but will not necessarily alter water use efficiency in semi - arid Mediterranean - type environments. Continuous cropping altered N - dynamics ; increases in inorganic N were dependent on the inclusion of a legume in the cropping sequence. Associated with the increase in inorganic N supply was a decrease in WUE by the subsequent wheat crop. Overall, estimates of water use efficiency, a common index of the sustainability of farming systems, in this study concur with reported values for the semi - arid Murray - Mallee region of southern Australia and other semi - arid environments worldwide. Soil water balance and determination of WUE for a series of crop sequences in this thesis suggests that the adoption of continuous cropping may increase WUE and confer a yield benefit compared to crop sequences including a legume component in this environment. No differences in total water use ( ET ) at anthesis or maturity were measured for wheat regardless of the previous crop. Soil evaporation ( E [subscript s] ) was significantly affected by crop canopy development, measured as LAI from tillering until anthesis in 2002, however total seasonal E [subscript s] did not differ between crop sequences. Indeed in environments with infrequent rainfall, such as the upper Eyre Peninsula, soil evaporation may be water - limited rather than energy limited and the potential benefits from greater LAI and reduced E [subscript s] are less. Greater shoot dry matter production and LAI due to an enhanced inorganic N supply for wheat after legumes, and to a lesser degree wheat after canola, relative to continuous cereal crop sequences resulted in increases in WUE calculated at anthesis, as reported by others. Nonetheless the increase in WUE was not sustained due to limitations on available soil water capacity caused by soil physical and chemical constraints. Access to more soil water at depth ( > 0.8m ) through additional root growth was unavailable due to soil chemical limitations. More importantly, the amount of plant available water within the ' effective rooting depth ' ( 0 - 0.8m ) was significantly reduced when soil physical factors were accounted for using the integral water capacity ( IWC ) concept. The difference between the magnitude of the plant available water capacity and the integral water capacity was approximately 90mm within the ' effective rooting depth ' when measured at field capacity, suggesting that the ability of the soil to store water and buffer against periodic water deficit was severely limited. The IWC concept offers a method of evaluating the physical quality of soils and the limitations that these physical properties, viz. aeration, soil strength and hydraulic conductivity, impose on the water supply capacity of the soil. The inability of the soil to maintain a constant supply of water to satisfy maximal transpiration efficiency combined with large amounts of N resulted in ' haying off ', and reduced grain yields. A strong negative linear relationship was established between WUE of grain production by wheat and increasing soil NO [subscript 3] - N at sowing in 2000 and 2002, which conflicts with results from experiments in semi - arid Mediterranean climates in other regions of the world where applications of N increased water use efficiency of grain. Estimates of proportional dependence on N [subscript 2] fixation ( % N [subscript dfa] ) for annual medics and vetch from this study ( 43 - 80 % ) are comparable to others for environments in southern Australia ( < 450mm average annual rainfall ). Such estimates of fixation are considered low ( < 65 % ) to adequate ( 65 - 80 % ). Nevertheless, the amount of plant available N present at sowing for subsequent wheat crops, and the occurrence of ' haying off ', suggests that WUE is not N - limited per se, as implied by some reports, but constrained by the capacity of a soil to balance the co - limiting factors of water and nitrogen. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2005.

Maya Mopan farmers in southern Belize face socio-economic hardships, persisting environmental constraints, and an unfavorable political climate that has prevented land tenure stability on reservation lands. This thesis describes the agricultural practices of a group of Mopan farmers and examines farm-site diversification and its relationship to ecological knowledge, out-migration, agricultural markets, and indigenous political systems. I also examine how modernization, religious conversions, and the Mopan's introduction into a capitalist economy have led to a decline in cultural practices and the augmentation of non-traditional behaviors among the younger generations. Data were obtained during my fieldwork in the Cayo and Toledo Districts of southern Belize from June-November, 2002. I conducted informal interviews with farmers and NGOs, engaged in participant observation techniques, documented 17 diversified Mayan farms, and formulated a self-administered questionnaire that was given to 38 students in the San Jose Village School. Additional data was acquired through voluntary work in farmers' fields and from available anthropological and agricultural literature. The results of this study indicate that Mopan farmers have diversified their farming systems by adopting new crop varieties, developing more sustainable agricultural techniques, increasing the production of cash crops, and adjusting their traditional labor systems. These findings are significant because they demonstrate ways in which farming communities throughout the tropics can improve their environments and economies amidst the influences of modernization, unsustainable development, and discriminatory government policies. / Graduation date: 2005

Support for sustainable agriculture by farmers and consumers is increasing as environmental and socio-economic issues rise due to more intensive farm practices. Site-specific crop management is an important component of sutainable agriculture, within which remote sensing can play an integral role. Field and image data were acquired over a farm in Saskatchewan as part of a national research project to demonstrate the advantages of site-specific agriculture for farmers. This research involved the estimation of crop biophysical parameters from airborne hyperspectral imagery using Spectral Mixture Analysis (SMA), a relatively new sub-pixel scale image processing method that derives the fraction of sunlit canopy, soil and shadow that is contributing to a pixel's relectance. SMA of three crop types (peas, wheat and canola) performed slightly better than conventional vegetation indices in predicting leaf area index (LAI) and biomass using Probe-1 imagery acquired early in the growing season. Other potential advantages for SMA were also indentified, and it was conclude that future research is warranted to assess the full potential of SMA in a multi-temporal sense throughout the growing season. / xiv, 194 leaves : ill. (some col.) ; 29 cm.