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.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-01T15:00:43Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Ingrid Alexssandra Neris Lino Dissertação PPGBF 2014.pdf: 662209 bytes, checksum: 777a9730d26a1dfaa03734a7ee039358 (MD5) / Made available in DSpace on 2016-04-01T15:00:43Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Ingrid Alexssandra Neris Lino Dissertação PPGBF 2014.pdf: 662209 bytes, checksum: 777a9730d26a1dfaa03734a7ee039358 (MD5) Previous issue date: 2014-02-25 / O uso combinado de inóculos micorrízicos e esterco bovino pode incrementar a produtividade vegetal e a fertilidade do solo. O objetivo do presente trabalho foi determinar se a aplicação de inóculos micorrízicos, com e sem adubação orgânica, influenciam positivamente a produtividade da cultura do milho e a atividade biológica do solo. A influência foi determinada em experimentos de campo conduzidos em 2012 e 2013 no município de São João, PE, com quatro tratamentos de inoculação (três inoculados e um sem inoculação) e dois de adubação orgânica (com e sem esterco bovino). Nas condições testadas, a inoculação com fungos micorrízicos arbusculares não foi suficiente para aumentar a produtividade e a composição mineral de plantas de milho em condições de campo, independente da adubação. A aplicação do esterco bovino em plantios de milho influenciou positivamente a produtividade, enquanto o efeito na composição mineral das plantas variou conforme o nutriente analisado e as condições hídricas às quais a cultura foi submetida. Os teores de proteínas relacionadas à glomalina e a atividade microbiana do solo não foram influenciados significativamente pela adubação orgânica e pela inoculação com FMA, o que pode estar relacionado ao tempo de duração do experimento, considerado insuficiente para permitir a mensuração dos efeitos do adubo e dos inóculos. A inoculação com FMA em sistemas agrícolas pode trazer benefícios significativos em longo prazo, uma vez que contribui com o potencial infectivo do solo, verificado pela maior densidade de glomerosporos no solo e maior colonização micorrízica nas plantas inoculadas. Doses maiores de inóculos micorrízicos devem ser analisadas em associação com doses menores de esterco bovino, visando aumento da produtividade da cultura. / The combined use of mycorrhizal inoculants and manure can increase crop productivity and soil fertility. The objective of this study was to determine whether the application of mycorrhizal inoculum, with and without fertilization, positively influence productivity of maize under field conditions, and soil biological activity. The influence was determined in field experiments conducted in 2012 and 2013 in the city of São João, PE, with four inoculation treatments (three inoculated and one non-inoculated) and two fertilization treatments organic manure (with and without manure). Under the conditions tested, inoculation with mycorrhizal fungi did not affect productivity and mineral composition of corn plants under field conditions, independent of fertilization. The application of manure in maize positively influenced productivity, while the effect on the mineral composition of the plants varied according to the nutriente analyzed and moisture conditions to which the culture was submitted. The levels of proteins related to glomalin and soil microbial activity were not significantly influenced by organic fertilization and the inoculation with AMF, which may be related to the duration of the experiment, considered insufficient to allow measurement of the effects of fertilizer and inoculants. Inoculation with AMF in agricultural systems can bring significant long-term benefits, as it helps with the infective potential of the soil, verified by the higher density glomerosporos the soil and greater mycorrhizal colonization in the inoculated plants. Higher doses of mycorrhizal inoculants should be analyzed in combination with lower doses of manure, aiming to increase crop productivity.

Orientador: Enrique Ortega Rodriguez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T23:34:31Z (GMT). No. of bitstreams: 1 Kamiya_DanieldeSouza_M.pdf: 3604427 bytes, checksum: e082451c244ea784a0083a8c79ba7bb6 (MD5) Previous issue date: 2005 / Mestrado / Mestre em Engenharia de Alimentos

Orientadores: Mara de Andrade Marinho, Jurandir Zullo Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-21T20:55:57Z (GMT). No. of bitstreams: 1 Walter_MicheleKarinaCotta_D.pdf: 5601129 bytes, checksum: 5c0f3ea57b4369e0f0ec8123daabfa91 (MD5) Previous issue date: 2012 / Resumo: No estado do Rio Grande do Sul a deficiência hídrica associada às limitações da qualidade física dos solos tem comprometido o rendimento da cultura da soja, resultando na maioria das vezes em prejuízos econômicos ao produtor e degradação dos recursos naturais. Os objetivos deste estudo foram avaliar a aptidão edafoclimática de terras no RS ocupadas com sistemas de sucessão e de rotação de culturas (soja, trigo, milho, ervilhaca, aveia e sorgo), assim como analisar a viabilidade econômica da conversão dessas áreas em florestas, com geração de créditos de carbono. A adequação do uso atual das terras foi efetuada a partir da avaliação da aptidão agrícola das terras. A contabilização do estoque de carbono nas culturas agrícolas foi realizada de forma direta, por meio de coleta de dados em área experimental da Embrapa Trigo, em Passo Fundo (PF) - RS, e em áreas comerciais de grãos, em Frederico Westphalen (FW) - RS. O estoque de carbono florestal foi estimado considerando cenários simulados com Eucalyptus grandis e Pinus taeda L. usando o modelo de contabilização de carbono CO2Fix. A análise econômica foi conduzida aplicando-se os critérios de avaliação econômica VPL, TIR e B/C. Os resultados demonstraram que o uso atual da maioria das terras em PF (84%) é adequado e está de acordo com a aptidão agrícola. Entretanto, em FW cerca de 27% das terras estão sendo utilizadas acima da sua capacidade suporte. As áreas avaliadas em PF apresentaram maior capacidade de estocagem de carbono tanto nos cenários agrícolas quanto nos florestais. As terras em FW apresentaram alta incidência e susceptibilidade à degradação, principalmente por erosão. O cenário de cultivo de eucalipto com rotação de sete anos e três ciclos de corte, manejado para produção de madeira para celulose foi o que apresentou maior capacidade para geração de créditos de carbono. Dentre os cenários manejados para produção de madeira serrada, o cultivo do pinus com rotação de 21 anos e dois desbastes proporcionou o maior número de créditos de carbono. A análise econômica demonstrou maior viabilidade dos sistemas florestais comparativamente aos sistemas de sucessão de culturas trigo/soja e trigo/soja - trigo/soja - trigo/milho atualmente implantados nas áreas estudadas. A inclusão de créditos de carbono em projetos de conversão de áreas agrícolas em florestais pode resultar em aumento da rentabilidade em aproximadamente 14% para o cenário com pinus e 15% e 7% para o cenário com eucalipto manejado para serraria e celulose, respectivamente. Conclui-se que nas áreas estudas a conversão dos sistemas de sucessão e rotação de grãos em floresta de eucalipto ou pinus com a geração de créditos de carbono constitui alternativa viável para investimentos de médios e longos prazos / Abstract: In the state of Rio Grande do Sul (RS) - Brazil, water deficiency and poor physical soil quality decrease the soybean productivity and, in the majority of the cases, cause not only economic losses to the producer but also degradation of the natural resources. The objectives of this study were to evaluate the edaphoclimatic suitability of lands in RS occupied with succession systems and crop rotation (soybean, maize, wheat, vetch, oats and sorghum), as well as analyze the economic and environmental viability of converting these areas in forests, with the generation of carbon credits. The suitability of land use was assessed using the methodology "Avaliação da Aptidão Agrícola das Terras". The accounting of carbon stock in the crops was conducted in a direct way, by collecting data in the experimental area of Embrapa Wheat, in Passo Fundo (PF) - RS, and in commercial areas of grains in Frederico Westphalen (FW) - RS. The carbon stock was estimated in simulated forest scenarios with Eucalyptus grandis and Pinus taeda using the carbon accounting model CO2Fix. The economic analysis was conducted by applying the criteria of economic evaluation NPV, IRR, and B/C. The results showed that the current use of most land in PF (84%) is in accordance with its agricultural potential. However, in FW 27% of the land is being used above its carrying capacity. The evaluated areas in PF showed higher carbon storage capacity in agricultural and forest scenarios. The areas in FW showed a high incidence and susceptibility of environmental degradation, especially with regard to the risk of erosion. The scenario of growing Eucalyptus grandis with seven years of rotation and three cycles of cutting, managed for pulpwood production, showed the greatest capacity to generate carbon credits. Among the scenarios handled for sawn timber production, the cultivation of pinus with rotation of 21 years and two thinnings resulted in the highest number of carbon credits. The economic analysis showed higher viability of forest systems compared to systems of succession planting wheat / soybeans and wheat / soybean - wheat / soybean - wheat / maize currently deployed in the areas studied. The inclusion of carbon credits in projects for converting farmland into forest can result in increased profitability. It is approximately 14% for the scenario with Pinus taeda and 15% and 7% in the scenario with Eucalyptus grandis for sawn timber and pulp respectively. The conclusion is that in the areas studied the conversion of succession and rotation of grain into eucalyptus or pinus forest with the generation of carbon credits is a viable alternative to investments in medium and long term / Doutorado / Planejamento e Desenvolvimento Rural Sustentável / Doutor em Engenharia Agrícola

Submitted in fulfillment of the requirements of the Master of Information and Communications Technology degree in Information Technology, Durban University of Technology, Durban, South Africa, 2017. / This dissertation reports on the original study that undertakes the development of a frugal information system to support subsistence farmers through the use of the Agricultural Production Systems Simulator (APSIM) as a support tool to assist them in optimal strategic decisions making. The field of agriculture is vast and in-depth and a number of critical factors like soil type, rainfall and temperature are involved that farmers have to take into account. Farmers persistently face the challenges of increasing and sustaining yields to meet with the populaces demand with often limited resources, which makes strategic decisions on what to plant, when to plant, where to plant and how to plant in a particular season imperative. The way in which this study attempts to solve this agricultural decision making problem is with the use of the APSIM. This technology platform provides an advanced simulation of agricultural systems that can enable subsistence farmers to simulate a number of variables ranging from plant types, soil, climate and even management interactions. This research presents a frugal web-based crop planning decision support system that subsistence farmers can take advantage with the use of the APSIM. The APSIM platform was used to run simulations for various regions with the results containing the expected level of success along with other useful information for a specified crop in the vicinity, using state of the art software platforms and tools ranging from Google Maps application programming interfaces, Microsoft’s model view controller framework, JavaScript and others. The validity of this system was tested through a number of design science methods including structural testing and illustrative scenarios, show capability of the information system. The results obtained from this evaluation show a small but powerful tool that has the capability of servicing a multitude of farmers with crop management decisions. / M

South Africa (SA) is food secure on a national level, however citizens in rural and marginalised areas face household food insecurity due to lack of access to this food. South Africa has low fertility soils and scarce water resources. Climate change reports of unpredictable weather conditions will further exacerbate these challenges. The majority of the agricultural production methods in SA are industrialised and rely heavily on external inputs. Alternative agricultural production methods which are environmentally less taxing, are affordable and yield nutritious food, need to be investigated and adopted. A long-term trial investigating the differences in yields between conventional and organic farming systems was established at the NMMU George Saasveld campus. A baseline study preceded the cropping seasons to establish pre-treatment soil conditions before the two farming systems were be implemented. The trial was a randomized complete block design split into organic, conventional and control plots. In the first cropping season (summer) three crops cabbage (Brassica oleracea var. capitata), sweet potato (Ipomea batatas) and cowpea (vigna ungucuilata) were planted under the different treatments. Soil fertility changes after application of chemical and organic fertilizer were measured. Soil pH and phosphorus increased whilst potassium and soil carbon decreased from baseline levels. The organic plots were found to have higher soil pH, potassium and carbon, whilst P was higher in the conventional plots. The organic cabbages had a yield 12% lower than conventional cabbages, organic cowpeas were 51% lower than conventional cowpeas. Baboons damaged sweet potato plots before maturity. Broccoli (Brassica oleracea var. italica), radish (Raphanus sativa) and green pea (Pisum sativum) were planted in the second cropping season (winter). Organic broccoli yields were 51% lower than conventional broccoli, organic green peas were 18 % lower than conventional green peas. The organic radish yields were 36% lower than conventional yields and this was statically significant. The yield differences were statically significant between control and conventional cabbages (25%) and broccolis (68%). The results indicate that there is on average an initial 25% yield difference between organic and conventional farming systems. Similar studies have shown that the yield gap can be reduced within three to four years. This study presents preliminary results of trials that are to continue for ten years, during which time the yield differences may vary.

Orientadores: Maristela Simões do Carmo, Sonia Maria Pessoa Pereira Bergamasco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-27T11:32:12Z (GMT). No. of bitstreams: 1 Lopes_AntonioWagnerPereira_D.pdf: 5863877 bytes, checksum: f421469d012dbefbafe028068cd6366e (MD5) Previous issue date: 2015 / Resumo: Objetivou-se proceder à análise de práticas agrícolas e estratégias constituídas por grupos de assentados da região de Araraquara e de Ribeirão Preto, localizados na região Central e Nordeste do Estado de São Paulo. Buscou-se discutir a perspectiva de um novo paradigma de produção, que venha substituir moldes comumente encontrados na produção da agricultura familiar, e a possibilidade de ações expressas em sinais voltados à Agroecologia. O objetivo deste trabalho foi realizar uma caracterização no tocante à produção, à alimentação, ao autoconsumo, à relação com os recursos naturais, com as políticas públicas - discutindo, através dos mesmos, perspectivas de desenvolvimento rural para os assentamentos, em modalidades distintas de assentamento: um PA e um PDS. Metodologia: foram realizadas inúmeras visitas a campo, com intuito de melhor conhecer o modo de vida dos grupos dos assentados, valiosas na construção da relação de confiança com os produtores; registros fotográficos e aplicação de 50 questionários - 31 no assentamento Bela Vista do Chibarro e 19 no assentamento Sepé Tiarajú, através de uma amostra em grupos de produção, no PA (Projeto de Assentamento) Bela Vista e, na existência de cooperativas, no PDS (Projeto de Desenvolvimento Sustentável) Sepé Tiarajú. Os atores que compõem a amostragem são produtores de quatros grupos do Bela Vista: Grupo da Palha, Grupo de Produtores Individuais de Hortaliças, Grupo Pedra D¿água, grupo dos que não aderiram à Cana e quatros cooperativas do Sepé Tiarajú: Cooperagrosepé, Fraterra, Cooperecos e Cooperfit. Pelos resultados obtidos, apresentaram-se as seguintes tendências: nos PAs mais antigos, predominam práticas convencionais, embora existam sinais de agrobiodiversidade, no plantio "embolado", no manejo do solo, na redução do uso de insumos na produção das hortas, na reedição de hábitos tradicionais na criação de suínos e aves. A renda mensal, cujo cálculo não apresenta plena exatidão ficou no Bela Vista em torno de R$ 2.000,00 e no Sepé Tiarajú, R$1.500,00. Nas duas modalidades, o autoconsumo mostrou a impossibilidade de ser dissociado da renda, sendo uma possível alavanca de segurança alimentar nos assentamentos e para a população do entorno. No assentamento Bela Vista, a escola, considerada modelo, atua como elemento irradiador das práticas sociais inovadoras no seio da comunidade. No Sepé Tiarajú, além da proibição dos agrotóxicos, o número crescente de SAFs, reforçado pela aprovação recente de um projeto no Comitê de Bacia hidrográfica, que vai implicar na instalação de 31 novos SAFs, o saldo organizativo expresso na boa relação entre as cooperativas, justificada por afinidade, reflete-se em todo o conjunto do assentamento, não apenas no sistema produtivo. Discutiu-se na tese sistemas produtivos vinculados a estratégias familiares que se fazem presentes nos dois assentamentos analisados. Igualmente foi investigada a influência de políticas públicas no desenvolvimento dos assentamentos, tendo sido constatado que os PAs mais antigos arcaram, de modo mais acentuado do que os PDSs, com o ônus da incerteza e da frágil presença do órgão gestor. A partir de 2004, as políticas públicas federais se transformam em alavancas possíveis de desenvolvimentos dos assentamentos, especialmente o PAA e o PNAE, o que vai depender em muito das ações levadas adiante pela gestão pública local / Abstract: The aim of this research was to analyze agricultural practices and strategies adopted by groups of settled families in the region of Araraquara and Ribeirão Preto, located in the Central and Northeastern region of São Paulo state. We have tried to discuss the production paradigm, which may substitute the manners usually found in the production of familiar agriculture and the possibility of actions expressed in signals voltados to Agroecology.The aim of this research is to carry out a characterization of production, food, self-consumption, the relationship with natural resources and with the public policies and, based on these aspects, to discuss perspectives of rural development for the settlements, in distinct modalities of settlements: a PA (Settlement Project) and a PDS (Sustainable Development Project). Methodology: several field visits were made with the aim of knowing better the way of life of the settled group, which were significant in the construction of a confidence relationship with the producers; photographic registers and the application of 50 questionnaires- 31 in the Bela Vista do Chibarro settlement and 19 in the Sepé Tiarajú, using a sample of the production groups in PA Bela Vista and, in case of existence of cooperatives, in the PDS Sepé Tiarajú. The actors who compound the sample are producers belonging to 4 groups from Bela Vista: " Grupo da Palha", Group of Individual Vegetable Producers, "Grupo Pedra d¿água", a group of settlers who didn't join sugarcane and 4 cooperatives of Sepé Tiarajú: Cooperagrosepé, Fraterra, Cooperecos e Cooperfit.The obtained results showed the following tendencies: in the oldest PAs, conventional practices are more prevalent, although there are signals of agrobiodiversity in the "embolden" planting, in the soil management, in the reduction of the use of inputs in the production of vegetables, in the reedition of traditional habits in poultry and pig raising. The monthly income, whose amount is not exact, reached around R$ 2.000,00 in Bela Vista and around R$ 1.500,00 in Sepé Tiaraju. In both modalities, home consumption showed the impossibility of divorcing it from the income, being a possible lever of food security in the rural settlements and for the surrounding communities. In Bela Vista Settlement, the school, considered as a model, acts as a central element of innovative social practices in the center of the community. In Sepe Tiarajú, besides the prohibition of agrotoxics, the crescent number of SAFs, reinforced by the recent approval of a project in the "Comitê de Bacia Hidrográfica", which will bring the installation of 31 new SAFs, the organizational balance expressed in the good relationship among the cooperatives, justified by affinity, reflects on the whole of the settlement, and not only on the productive system. We discussed productive systems linked to common strategies which are present in both analyzed rural settlements. We also investigated the influence of public policies in the development of settlements, and we verified that the oldest PAs bore, more than the PDSs, with the burden of uncertainty and of the fragile presence of the management organ. Since 2004, the federal public policies have become possible levers for settlements¿ developments, specially the PAA and the PNAE, depending mainly on the actions developed by the local public management / Doutorado / Planejamento e Desenvolvimento Rural Sustentável / Doutor em Engenharia Agrícola

Orientador: Alan Rodrigo Panosso / Resumo: O bioma Cerrado tem sofrido modificações nas últimas décadas, perdendo parte de sua cobertura original para culturas anuais, pastagens e florestas plantadas, tendo diferentes usos da terra. Neste trabalho, foram estudadas as interações entre os diferentes usos da terra em áreas do bioma Cerrado, bem como da dinâmica de carbono no solo e os fatores latentes formados pelos atributos físicos e químicos do solo, por meio de modelos de análise de equações estruturais, com auxílio das técnicas estatísticas multivariadas. Ensaios experimentais foram conduzidos na Fazenda de Ensino, Pesquisa e Extensão (FEPE/UNESP), localizada em Selvíria-MS: Floresta plantada de Eucalipto - Eucalyptus camaldulensis (EU); Floresta plantada de Pinus - Pinus caribaea var. hondurensis (PI); Sistema silvipastoril (SI) com uma área contendo floresta plantada de Aroeira (Myracrodruon urundeuva) e capim Braquiária (Brachiaria decumbens, e Mata Nativa (MN). Foi estudado os efeitos dos atributos físicos: densidade do solo (Ds), macroporosidade (Ma), microporosidade (Mi) e químicos com ênfase especial nas propriedades relacionadas à dinâmica do carbono no solo: matéria orgânica do solo (MO), estoque de carbono do solo (EstC), estoque de nitrogênio do solo (EstN), relação carbono e nitrogênio (C/N) e o grau de humificação da matéria orgânica do solo (HLIFS). A emissão de CO2 do solo (FCO2), umidade e temperatura do solo foram avaliados nas áreas durante três períodos distintos (definidos a partir do regime hídr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Cerrado biome has undergone modifications in recent decades, losing part of its original cover to annual crops, pastures and planted forests, having different land uses. In this work, the interactions between the different land uses in areas of the Cerrado biome, as well as the soil carbon dynamics and the latent factors formed by the physical and chemical attributes of the soil through structural equation analysis models were studied. with the aid of multivariate statistical techniques. Experimental tests were performed at the Teaching, Research and Extension Farm (FEPE / UNESP), located in Selvíria-MS: Eucalyptus planted forest Eucalyptus camaldulensis (EU); Planted Pine Forest - Pinus caribaea var. hondurensis (PI); Silvipastoral system (SI) with an area containing Aroeira (Myracrodruon urundeuva) and native grass (Brachiaria decumbens), and Mata Nativa (MN). The effects of physical attributes: soil density (Ds), macroporosity (Ma), microporosity (Mi) and chemicals attributes were studied with special emphasis on properties related to soil carbon dynamics: soil organic matter (MO), soil carbon stock (EstC), soil nitrogen stock (EstN), carbon and nitrogen ratio (C / N), and the degree of soil organic matter (HLIFS). Soil CO2 emission (FCO2), soil moisture and temperature were evaluated in the areas during three distinct periods (defined from the water regime observed in the areas) called P1, P2 and P3, season rainfall, drought and transition, respectively, between March... (Complete abstract click electronic access below) / Doutor

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2016. / Despite the expansive size of the Bokoni complex, our knowledge with regards to many aspects of its occupancy is limited. Due to the agriculturally centred nature of the Bokoni, it is important to understand this facet of Bokoni life from as many perspectives as possible. This project aims to take us one step closer to achieving a deeper understanding of the agricultural practices of the Bokoni people. Through my fieldwork and the processing of collected data on land management practices of this society have been explored. Additionally Khutwaneng and the Bokoni complex in general, provide an interesting case study in the role of resilience in agricultural communities. Their agricultural success is inseparably linked to the adaptive strategies employed throughout their occupancy. This allowed for the consideration of the recursive relationship between resilience and sustainability, furthering our understanding of the Bokoni complex. / LG2017

A rapidly expanding world population and extreme climate change have made food production a crucial challenge in the twentyirst century. Therefore, improving crop production through agricultural management could be an effective solution for this challenge. However, due to the associated cost and time to perform field works, researchers widely rely on agricultural system modeling to examine the impacts of different crop management scenarios. However, due to the complexity of agricultural system modeling, their applications in producing practical knowledge for producers are limited. Concurrently, deep learning techniques have been recognized as a preferred method when dealing with large datasets. This study was performed in three phases. First, A deep learning network was utilized and trained by incorporating a large number of datasets produced by the Decision Support System for Agrotechnology Transfer (DSSAT) model. To the best of our knowledge, no research has been done in the literature on modeling a cropping system by deep learning. An model accuracy level of around 98\% was obtained, and it was 770 times faster than classical crop models DSSAT in calculating 900,000 different crop growth scenarios. However, The second phase of the study examined the robustness of the deep learning model under a wider range of environmental factors (e.g., different irrigation and climatological conditions) while a deep learning structure was desired compare to the first study. To optimize the deep learning structure, three variable reduction methods were used (Bayesian, Spearman, and Principal Component Analysis). The result of this study showed that a deep learning structure could be developed that has a similar accuracy level as the original model while the structural size was reduced up to 80 times. In the third phase of the study, three techniques (L1/L2 regularization, and neurons dropout) were used to address the overfitting problem in some deep learning models. The L2 regularization was identified as the most effective method that increased model generalization and reduced overfitting. The overall results from this study demonstrated the effectiveness of the proposed deep learning technique in replicating the yield results from crop modeling under different climatological and management conditions.