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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.
71

Mudanças climáticas no Brasil: efeitos sistêmicos sobre a economia brasileira provenientes de alterações na produtividade agrícola / Climate change in Brazil: systemic effects on the Brazilian economy coming from changes in agricultural productivity

Souza, Bruno Santos de 10 August 2018 (has links)
Este trabalho mede o impacto econômico que as mudanças climáticas projetadas para as regiões brasileiras podem ter até o final do século. Em particular, estima o impacto direto que essa mudança no padrão climático terá sobre a produtividade das principais culturas agrícolas do país e o impacto indireto dessas mudanças na economia brasileira como um todo. Ademais, constrói um índice de vulnerabilidade que permite detectar quais são as regiões brasileiras mais vulneráveis em termos de mudanças climáticas para o período estudado. Por fim, utiliza metodologia proposta na literatura a fim de tratar da incerteza dos resultados de maneira explícita. A análise é realizada com dados de soja, cana-de-açúcar, milho, feijão café e laranja entre 1994 e 2015. Essas culturas representam cerca de 82% área de cultivo agrícola do país. Além disso, o modelo inter-regional de EGC usa os dados mais recentes disponíveis em sua calibragem e capta a interdependência regional dos 27 Estados brasileiros. Por fim, o trabalho usa as projeções para o padrão regional de mudanças climáticas fornecido pelo 5º Assessment Report do IPCC (AR5). Os resultados apontam para um impacto econômico bastante heterogêneo entre as regiões brasileiras. Em termos diretos, as perdas agrícolas totais até o final do século variam de 9,7% a 55,6% do PIB brasileiro até o final do século. Sob o aspecto regional, os Estados que apresentam maiores perdas são São Paulo, Paraná e Minas Gerais em todos os cenários. Os impactos de 2ª ordem derivados dessas perdas de produtividade variam de R$2,2 trilhões à R$ 9,2 trilhões a depender dos cenários e se estão mais concentrados nos Estados da região Sul, Sudeste e Centro-Oeste. / This study measures the impact Brazil has to have until the end of the century. In particular, estimating the impact that does not refer to a climate model on the Brazilian economy as a whole. In addition, construct the index of vulnerability that could detect those that are the most vulnerable regions in terms of climatic changes for the studied period. Finally, in the critical analysis, in order to treat the uncertainty of the results explicitly. The analysis is performed with data on soybean, sugarcane, corn, beans and orange between 1994 and 2015. The 6 countries represent 86% of the country\'s agricultural area. In addition, the CGE interregional model uses the most recent data on its calibration and capture in a regional interdependence of the 27 Brazilian states. Finally, the paper uses as projections for the regional pattern of change control by the IPCC\'s 5th Assessment Report (AR5). The results point to a very heterogeneous economic impact among the Brazilian regions. In direct terms, as the successive exchange rates until the end of the year, they vary from 9.7% to 55.6% of Brazilian GDP by the end of the century. Under the regional aspect, the states of which are most important are São Paulo, Paraná and Minas Gerais in all scenarios. The second-highest ratings ranged from R $ 2.2 trillion to R $ 9.2 trillion from the scenarios and are more concentrated in the states of the South, Southeast and Midwest
72

The Political Economy of Agricultural Development in Nigeria

Nwachukwu, Jude Uwaoma January 2016 (has links)
This dissertation is a case study, which examines the state of agricultural development in Nigeria. The study is intended to be a mirror for a wider undertanding of the state of agriculture Sub-Saharan African (SSA). Pitching its tent in a typical rural Nigerian agrarian community, and applying the political economy ideological framework, the study examines factors that impact and shape agricultural production in the country. It employs the plethora of social research techniques at the disposal of applied anthropologists including structured and unstructured interviews, questionnaires, participant observation, probing for history, and the use of photography and video recording among others. The study worked with a wide focus group including farmers, traders and government officials and analyzes field data through descriptive data analysis; the use of tables and charts; and comparing of results with related studies. The study found that many factors form a landscape and conspiracy of far-reaching significant negative impact on Nigerian farmers and hence on the agriculture sector of the whole country. The factors negatively impacting agricultural development in Nigeria include land tenure systems rooted in the social organization of farming communities; continually increasing populations against limited and constantly decreasing farmland size; lack of capital especially for the adoption of improved agricultural production technology; incessant conflicts; mass rural-urban migration; low level of education; repressive and exploitative State apparatus; systemic corruption of government officials; excessive dependence of oil economy to the exclusion of agricultural economy; application of institutional and economic development policies that are unfavorable to the agriculture sector; and poor or total lack of infrastructure among others. Correspondingly, the constellation of unfavorable social condition these factors create produces very far-reaching consequences for farmers and the country at large. These indlude farmers producing at levels of productivity below their potential; food insecurity; constantly rising poverty especially among Nigerian rural farmers; roof-high rate of unemployment; backwardness of other sectors that work hand-in-glove with agricultural production; poor health and reduced length of life directly connected with malnourishment; further occurrence of conflicts among and between communities as a result of poverty and hunger; sharp and continuous fall of farmers’ contribution to national GDP; inability of rural agricultural development to translate into rural and community development; entrenched poverty cycle especially among rural farming families; general backwardness in the socioeconomics of Nigerian rural farmers; and many more. In response to these telling findings, and in order to mitigate if not overcome the factors and sociopolitical, economic and institutional factors and conditions that militate against agricultural development in Nigeria, the study lays out some recommendations revolving around the installation and maintenance of policies that are pro-poor and pro-agriculture in order especially to boost agricultural productivity and ultimately to help lift farmers out of the assaults of poverty, food insecurity, hunger, and other problems that go with these. The recommendations fronted by the study cover the areas of the problems discovered especially that there needs to be installed institutions to effect changes in land tenure system; improvement in conflict management and resolution; giving back the democracy of agricultural production to farmers by restoring the sector and its former place in the overall economy; disengaging agriculture from its entrenchment in the “project” disposition associated with the development ideology; and above all, allowing agriculture to be a “process” in the hands of the people. In engaging in this on-going dialogue, this study has set to its merit the standard of how an applied anthropologist can contribute to wider study and understanding of social issues in Nigeria and in SSA at large.
73

Analyses of the agricultural production during the era of rural reform in China

Tsang, Ho Yee 01 January 1998 (has links)
No description available.
74

The effects of irrigation and nitrogen on productivity, marketable yield and [supercript 1]H-NMR based metabolic profiling of African nightshade (Solanum retroflexum)

Masemola, Makhutse Clive 09 1900 (has links)
Efficient agronomic practices are vital for achieving sustainable management of water resources and N for producing highly nutritious leafy vegetables to curb malnutrition and poverty. The importance of proper N and irrigation of sustainable crop production is well recognised in literature, although irrigation and N application rate guidelines for ALV’s might not be sufficient for advisory purposes, especially for smallholder and commercial farmers. The limited access is attributed by factors such as the lack of commercialisation as a result of limited agronomic information describing optimum management options for S. retroflexum. Availability of such information would contribute to successful commercialisation of this crop. The primary objective of this study was to establish optimum agronomic management practices for S. retroflexum for smallholder farmer as well as commercial production in South Africa. This project consists of three main components with the overall objective to evaluate agronomic management practices of irrigation and N application on the marketable yield, nutritional water productivity and 1H-NMR metabolic profiling under a rainshelter. The results suggested that S. retroflexum responded positively to N application rates until an optimum marketable yield was obtained at 150 kg N·ha-1 with I66%FC, followed by the I100%FC with 150 kg N·ha-1,while, the lowest biomass was recorded in the I33%FC irrespective of the N application rate. This also indicates of how S. retroflexum is affected by insufficient irrigation, even at sufficient N application rates. N and irrigation are key factors limiting plant survival and growth and low applications has adverse effects on the marketable yield of S. retroflexum. Dry matter production increased with the higher N application and a linear increase was observed with N application having a significant effect on the dry matter production. Maximum irrigation use efficiency (IUE), was obtained in the moderately irrigated treatment (I66%FC) and the 150 kg N·ha-1, followed by the I100%FC and 150 kg N·ha-1. The stressed irrigation and N treatments showed sustainably low irrigation use efficiency as compared to the well irrigated treatment. This suggests the competitive capacity of S. retroflexum roots to draw water from deeper parts of the soil profile, during stressed conditions to maintain the turgor pressure, indicating that production of S. retroflexum is possible in arid areas where water could be a limiting input, but might not be profitable for farmers. However, the biomass yields obtained under the less irrigated soil water conditions may lack the quality needed to market the produce. The NWP for Zn and Fe showed significant differences among the irrigation and N treatments. Although the NWP of Mg in S. retroflexum was neither influenced by irrigation nor N application, with no statistical differences between the irrigation and N application observed. Among the different irrigation and N treatments evaluated, I33%FC obtained the lowest NWP irrespective of the N application rate, followed by I100%FC. The NWP increased linearly with an increase in N application. Optimum Fe NWP was obtained with 150 kg N ha-1, but declined significantly at application 225 kg N ha-1 in I33%FC and I100%FC. Maximum Fe NWP was obtained with I66%FC with 150 kg N ha-1. The NWP Fe for S. retroflexum in this study, are acceptable when compared to those obtained in literature. Therefore a significant interaction between N and irrigation application exist, with respect to Fe and Zn availability of S. retroflexum, which could be ideal for Fe and Zn malnutrition alleviation in resource poor households. 1H-NMR based metabolomic profiling was utilized for compound annotation as effected by irrigation and N. Chlorogenic acid, proline, sucrose and trigonelline were associated with separation in the irrigation treatments. Since no separation of the irrigation or N treatments was observed with the PCA, an OPLS-DA plot was constructed. A pairwise comparison of the I33%FC and I100%FC samples was done, which provided better separation between the clusters for the first harvest. Even better separations were observed with a pairwise OPLSDA analysis of the I33%FC and I100%FC samples for the second harvest. Primary metabolites such as sucrose, and proline and secondary metabolites trigonelline and chlorogenic acid were responsible for grouping of the stressed irrigation treatment as compared to the well irrigated treatment. Main findings of the study suggest that S. retroflexum is highly nutritious in Fe, Zn and Mg, which might play a significant role in malnutrition alleviation. Solanum retroflexum requires sufficient soil water content, for achieving high nutrient yield and nutritional water productivity. The results clearly illustrate that the perception that S. retroflexum grow well on low soil fertility mostly practised in rural and smallholder farming is incorrect and misleading. Moreover, S. retroflexum can be an ideal cropping system for smallholder and commercial farmers in water scarce areas such as South Africa, although marketable yield is severely affected. / Agriculture and  Animal Health / M. Sc. (Agriculture)
75

Seleção genotípica e parâmetros genéticos da mamona influenciados por modelos fixos, aleatórios e mistos /

Piedade, Gabriela Nunes da. January 2019 (has links)
Orientador: Maria Márcia Pereira Sartori / Banca: Juliana Parisotto Poletine / Banca: Marcela Aparecida de Moraes / Resumo: Os efeitos da interação genótipos x ambientes dificultam a recomendação de cultivares de mamona (Ricinus communis L.) com características agronômicas satisfatórias, devendo-se o melhorista atentar-se à correta avaliação dos dados. Objetivou-se neste estudo avaliar os diferentes modelos em experimentos de melhoramento de mamona FCA Porte Baixo e compará-los com a análise tradicional de experimentos agrícolas, no que se refere aos parâmetros genéticos obtidos e a ordenação dos genótipos avaliados. Para tanto, foram utilizados dados de experimentos desenvolvidos nos anos de 2014 e 2015 nos municípios de Botucatu, Ilha Solteira, Penápolis e São Manuel, na época de semeadura da safra, nos quais 20 linhagens S5 foram distribuídas em delineamento experimental de blocos casualizados com três repetições. Com os dados de produtividade média dos grãos, análises de variância conjunta (ANOVA), considerando os diferentes modelos: fixo, aleatório e misto (bloco aleatório e fixo, ambiente e linhagem fixo), foram realizadas, assim como foram obtidos os componentes de variância associados aos efeitos aleatórios e os componentes quadráticos associados aos efeitos fixos. Parâmetros utilizados em programas de melhoramento genético e o ordenamento dos genótipos, também foram calculados. Observou-se que os valores da estatística F, assim como sua significância, obtidos na ANOVA, apresentaram variações de acordo com o modelo utilizado. Houve diferença entre os componentes de variância e quadráticos,... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The effects of genotype x environment interaction make it difficult to recommend castor bean (Ricinus communis L.) cultivars with satisfactory agronomic characteristics, and the breeder should pay attention to the correct evaluation of the data. The aim of this study was to evaluate the different models in FCA Porte Low castor bean breeding experiments and compare them with the traditional analysis of agricultural experiments, regarding the genetic parameters obtained and the ordering of the evaluated genotypes. For this purpose, data from experiments developed in 2014 and 2015 in the municipalities of Botucatu, Ilha Solteira, Penápolis and São Manuel at the time of sowing were used, in which 20 S5 strains were distributed in a randomized complete block design with three repetitions. With the average grain yield data, joint variance analysis (ANOVA), considering the different models: fixed, random and mixed (random and fixed block, environment and fixed lineage), were performed, as well as the variance components were obtained, associated with random effects and the quadratic components associated with fixed effects. Parameters used in breeding programs and genotyping were also calculated. It was observed that the F statistic values, as well as their significance, obtained in ANOVA, presented variations according to the model used. There was a difference between the variance and quadratic components, as well as between the estimated genetic parameters. The methodologies of traditional analysis, random model and mixed model, provided the same ordering of genotypes, except for the model where the block assumes fixed effect. Avoid the model in which all sources of variation have a random effect, in addition to the model in which only the source of variation block assumes a fixed effect. In contrast, when environment assumes a fixed effect, favorable estimates are obtained. / Mestre
76

Management practices, soil quality and maize yield in smallholder farming systems of central Malawi

Pelletier, Bernard, 1964- January 2000 (has links)
No description available.
77

THE POTENTIAL OF BIOCHAR TO ENHANCE ENVIRONMENTAL SUSTAINABILITY IN SWEDEN

Pensulo, Chibesa January 2012 (has links)
Environmental sustainability in Sweden is challenged by rising greenhouse gas emissions from transportation, input-intensive agriculture and potentially unsustainable removal of organic material from forests and farmland. The Swedish government is working towards sixteen environmental quality objectives in order to overcome these problems, among others.  The past decade gave rise to an international research community dedicated to investigate the age-old practice of applying charcoal to soil, practiced most notably by ancient civilisations in the Amazon region of South America. The high level of interest and controversy around this subject inspired this investigation of biochar’s potential benefits in Sweden.  A scientific study was conducted to examine the potential of biochar to enhance environmental sustainability in Sweden. This was largely a desk study, supplemented by expert interviews, GIS map work, an experiment and mathematical analysis.  It was found that there was insufficient research to date to prove the agronomic benefits of biochar in Sweden. More field studies are required to build up the evidence of its potential. Furthermore, as the rate of mineralization of the carbon content is dependent on numerous factors, including the composition of the soil to which the biochar is applied, it is difficult to conclusively define biochar’s carbon storage potential.  This study adds to the existing body of knowledge on the subject by integrating the conclusions from a variety of studies and expert opinions, as well as by providing maps indicating land areas in Sweden that would be likely to benefit from biochar application.
78

Agricultural policy and soil fertility management in the maize-based smallholder farming system in Malawi /

Tchale, Hardwick. January 2006 (has links) (PDF)
Univ., Diss.--Bonn, 2005.
79

What is the impact of livelihood strategies on farmers' climate risk perceptions in the Bolivian highlands

Rees, Lisa Marie. Valdivia, Corinne B. January 2009 (has links)
The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on December 18, 2009). Thesis advisor: Dr. Corinne Valdivia. Includes bibliographical references.
80

The impact of the global-warming-led climate change on agricultural production of major grain producing regions in China

Tsang, Heung-chun., 曾向俊. January 2011 (has links)
published_or_final_version / Applied Geosciences / Master / Master of Science

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