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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.
441

Thermal Reduction of Common Food-Borne Pathogens During Composting

Cooper, Ashley January 2015 (has links)
Soil amended with manure has been implicated as a source of produce contamination leading to foodborne gastrointestinal-disease outbreaks. While current composting guidelines require temperatures ≥ 55°C for 3 days to destroy bacterial pathogens, these requirements have not been evaluated for all pathogens. Investigation of parasite survival in manure required development of a flow cytometry method integrating the cell-impermeant viability dye SytoX for simultaneous quantification and viability assessment of Cryptosporidium and Giardia oocysts/cysts. Further studies will be required to apply this method to investigate thermal reduction in parasites. Studies conducted with bacterial pathogens indicated that E. coli O157:H7 survived longer than other pathogens at 50°C to 55°C. Listeria monocytogenes survived significantly better in chicken manure compared to cow manure at 50°C to 55°C. Results suggest composting guidelines are adequate for bacterial pathogen reduction; however, testing for E. coli O157 along with Salmonella may increase confidence in compost safety.
442

Effet d’une pollution (métaux lourds et pesticides) et d’amendement (Fumier) sur les activités enzymatiques de différents sols

Sagna, Bacary 23 November 2009 (has links)
La fertilité, la pollution de l’écosystème sol sont devenues aujourd’hui des préoccupations etdes problèmes écologiques majeurs. L’objectif de cette étude est d’arriver à travers l’activitémicrobienne (hydrolyse de la FDA) et un large panel de 16 enzymes (phosphatases,hétérosidases, polysaccharidases, oligosaccharidases, oxydasses), à appréhender l’impact depolluants et d’amendement. Cinq sols aux caractéristiques physico-chimiques différentes ontété étudiés, et ont été soumis à différents traitements réalisés en microcosmes. Ces traitementsont porté sur l’ajout de zinc, cadmium, d’un herbicide, d’un insecticide, d’un fongicide, d’unnématicide et de fumier.L’expression des activités enzymatiques dépend fortement du type de sol. Ainsi lafraction limoneuse du sol jouerait un rôle crucial dans l’expression des enzymes telluriques. Parailleurs les résultats obtenus ont montré que des sols très proches d’un point de vu physicochimiquene le sont pas forcément au niveau enzymatique et microbien.L’ajout du fumier dans nos différents sols a entraîné quelque soit le type de sol defortes modifications positives des activités microbiennes et enzymatiques. L’effet stimulateurdu fumier sur l’activité microbienne et enzymatique dépend non seulement des paramètres dusol mais surtout de son activité initiale. Entre autre, l’impact positif du fumier est moinsmarqué dans les sols ayant des activités enzymatique ou des quantités de matière organiquefaibles. La tendance semble s’inversée concernant l’activité microbienne.L’impact des métaux lourds sur l’activité microbienne et les enzymes testées esttributaire des paramètres (argile, M.O), et de la nature des métaux lourds. Le cadmium s’avèreplus néfaste que le zinc. Si la majorité des activités enzymatiques sont diminuées par laprésence de métaux lourds d’autres en revanche ne sont pas impactées.La présence de pesticides dans nos sols révèle une grande disparité de résultat. Selon letype de sol, le type d’enzyme, une inhibition, un effet neutre ou bien une stimulation del’activité microbienne ou enzymatique par les pesticides ont été observés.Cette étude a permis de montrer que les enzymes sont très réactives aux différentesperturbations anthropiques quelque soit le type de sol considéré. Cependant cette réactivité setraduit par une très grande diversité des réponses. Cette diversité de réponse résulte d’ungrand nombre de paramètres liés aussi bien aux caractéristiques physico-chimiques quebiologiques du sol. Il n’a donc pas été possible de définir une enzyme ou groupe d’enzymesusceptible d’être utilisée comme indicateur pour l’ensemble des sols ou des traitements / Fertility and pollution of the soil ecosystem have become today’s concern and major ecologicalproblems. The objective ofthis study is to estimate through microbial activity (hydrolysis ofFDA) and a wide range of 16 enzymes (phosphatases, heterosidases, polysacchridases,oligosaccharidases, oxydase), the impact of pollutants and amendment in soil. The five soilsstudied are different regarding their physical and chemical characteristics. This soils are areexposed to different treatments in microcosms. These treatments consist to pollute our soilswith heavy metals (zinc, cadmium), pesticides (herbicide, insecticide, fungicide, nematicide)or to add manure.Our results showed that the expression of enzymatic activities depends on soil type.Thus, the silt fraction of soil plays a crucial role in this expression of soil enzymes. The soilswith physico-chemical characters are very similars, have not necessarily the same enzymaticprofile and expression or microbial activity.The presence of manure on our differents soils greatly increased the enzymatic andmicrobial activities. The stimulatory effect of manure depends on soil parameters but also theinitial enzymatic and microbial soil activities. The results showed that the positive impact ofmanure is less pronouncing in soils where the initial enzyme activity and organic matterquantity are low.The impact of heavy metals on microbial activity and enzymes tested depends on soilparameters (clay, organic matter, pH, ...) and nature of heavy metal. Cadmium is more toxicand longer decreases enzymatic and microbial activities than zinc. The presence of heavymetals in soils has reduced most of enzymes activity. Other enzymes are also unchanged orincreased by the pollutants.Soil pollution by pesticides show a large disparity and diversity of results. Dependingon soil type or the enzyme tested, the diffrents results showed an increase, neutral effect ordecrease by pesticides of enzymes and microbial activities.Watever the type of soil considered, this study has shown that soil enzymes are verysensitive and responsive to human disturbance. The reactivity of telluric enzymes is manifestedby a very large diversity of responses. Diversity responses of soil enzymes is depended tophysico-chemical characters and also soil biological parameters. In this study, it is verydifficult to define one or group of enzymes as a bioindicator for all soil disturbances
443

Direct and residual effects of organic and inoganic fertilizers on soil chemical properties, microbial components and maize yield under long-term crop rotation

Tedla, Asfaw Belay 05 July 2010 (has links)
Management-induced degradation of soil chemical and microbial quality is one of the most pressing concerns and a considerable threat to the sustainability of agroecosystems. However, information on this important issue is limited and largely based on short-term studies. A long-term experiment initiated in 1939 at the University of Pretoria provided a unique opportunity to assess the direct and residual effects of manure and inorganic fertilizers on soil chemical properties, microbial components and maize yield in rotation with field pea. Long-term addition of manure resulted in increased total organic C (TO C), total Nand available P levels in the soil. Seasonally, these nutrients exhibited variations that appeared to be related to influences of crop rotation. Soil N content in an adjacent native site remained relatively constant but tended to increase in the control and manured plots. Soil microbial biomass C, Nand P and microbial populations were affected by previous manure application as well as by crop rotation. Microbial biomass and numbers were generally higher in the manured plots. Manure application also had substantial residual effects and resulted in maize grain yields higher than in the control. Long-term NPK application resulted in decreased TOC and basic cation contents, and lowering of soil pH. The decrease in TOC was greater in single fertilizer treatments whereas basic cation contents and pH declined more in the balanced fertilizer treatments. Soil microbial biomass and numbers were influenced by, and exhibited qualitative changes in response to, long-term fertilization. Crop rotation also exerted effects on chemical and microbial properties of the soil. Maize grain yield showed significant increases in response to balanced fertilizer treatments. Response of maize to simple fertilizer applications was not beneficial in terms of yield returns. These results suggest that judicious use of inorganic fertilizers may, in the long-term, maintain soil quality and productive capacity. A comparison of the effects of residual manure and NPK fertilizers on the content of selected nutrients, microbial properties, C and N inputs, tissue nutrient concentration and crop yield showed differences due to treatments. TOC, total N and available P levels were increased due to residual manure alone or in combination with NPK fertilizers. C and N inputs and tissue P concentration were also generally higher in manured than in the NPK treatment. However, the higher increase in nutrient contents of manured plots was not reflected in microbial properties of the soil. Despite lower nutrient levels, the NPK treatment resulted in relatively greater increases in microbial properties of the soil. The differential responses were largely due to differences in quality and decomposability of organic material. Organic material in the NPK treatment appeared to have a higher decomposition and turnover rate than in other treatments, suggesting that C limitation in soils of low C but good nutrient supply may be compensated by high turnover rates of the available organic materials. The beneficial effect of residual manure on microbial properties and crop yield was decreased by application of supplemental N fertilizer but remained unaffected by application of supplemental K fertilizer. The depressive effect of excess soil P levels on soil microbial properties and crop yield was exacerbated by supplemental N fertilizer and mitigated by supplemental manure and K fertilizer applied to residual P. The decrease in available P levels due to supplemental K application implies that this may serve as a viable alternative to ameliorate soils with excess P levels. / Thesis (PhD)--University of Pretoria, 2010. / Plant Production and Soil Science / unrestricted
444

Consorciação intercalar em linha com crotalária e feijão guandu anão na soqueira da cana-de-açúcar / Row intercropping with Sunnhemp and Pigeon Pea in the ratoon sugarcane

Trento Filho, Egyno 01 February 2010 (has links)
Made available in DSpace on 2016-01-26T18:56:20Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 116799 bytes, checksum: 3e8130b0b12cb48079c689686d6e6753 (MD5) Previous issue date: 2010-02-01 / Two great challenges for the sugar cane agribusiness are the reduction of the investment and of the operational cost to increase the competitiveness of the sugar and of the etanol. The improvement of the chemical and physical quality of the soil in elapsing of the years of cultivation of the cane is one of the factors that contribute to win those challenges. The objective of this work was of evaluating the effect of the row intercropping with Crotalaria juncea (Sunnhemp) and Cajanus cajan (Pigeon pea) in the productivity, technological quality and margin of industrial contribution of the ratoon sugarcane. The experiment was accomplished in Valparaíso - SP in the Usina da Barra S/A subsidiary Univalem, using the statistical delineation in randomized blocks with four repetitions each. The results demonstrated that the productivity of stems for hectare of the leguminous was similar to the control. The organic compost as only nutrition source presented the largest productivity. The technological quality was similar in all of the treatments. The treatments Compost organic, Control and Sunnhemp without compost presented Margin of Contribution Industrial fellow creatures amongst themselves and superiors to the other treatments. / Dois grandes desafios para a agroindústria canavieira são a redução do investimento e do custo operacional para aumentar a competitividade do açúcar e do etanol. A melhoria da qualidade química e física do solo no decorrer dos anos de cultivo da cana é um dos fatores que contribuem para vencer esses desafios. O objetivo deste trabalho foi de avaliar o efeito da consorciação intercalar em linha com Crotalaria juncea e Cajanus cajan na produtividade, qualidade tecnológica e na margem de contribuição industrial da soqueira de cana-de-açúcar. O experimento foi realizado em Valparaíso - SP na Usina da Barra S/A filial Univalem, utilizando o delineamento estatístico blocos completos ao acaso com quatro repetições. Os resultados demonstraram que a produtividade de colmos por hectare das leguminosas foram semelhantes à testemunha. O composto orgânico como única fonte de nutrição apresentou a maior produtividade. A qualidade tecnológica foi semelhante em todos os tratamentos. Os tratamentos Composto orgânico, Testemunha e Crotalária sem composto apresentaram Margem de Contribuição Industrial semelhantes entre si e superiores aos outros tratamentos.
445

Consorciação intercalar em linha com crotalária e feijão guandu anão na soqueira da cana-de-açúcar / Row intercropping with Sunnhemp and Pigeon Pea in the ratoon sugarcane

Trento Filho, Egyno 01 February 2010 (has links)
Made available in DSpace on 2016-07-18T17:51:05Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 116799 bytes, checksum: 3e8130b0b12cb48079c689686d6e6753 (MD5) Previous issue date: 2010-02-01 / Two great challenges for the sugar cane agribusiness are the reduction of the investment and of the operational cost to increase the competitiveness of the sugar and of the etanol. The improvement of the chemical and physical quality of the soil in elapsing of the years of cultivation of the cane is one of the factors that contribute to win those challenges. The objective of this work was of evaluating the effect of the row intercropping with Crotalaria juncea (Sunnhemp) and Cajanus cajan (Pigeon pea) in the productivity, technological quality and margin of industrial contribution of the ratoon sugarcane. The experiment was accomplished in Valparaíso - SP in the Usina da Barra S/A subsidiary Univalem, using the statistical delineation in randomized blocks with four repetitions each. The results demonstrated that the productivity of stems for hectare of the leguminous was similar to the control. The organic compost as only nutrition source presented the largest productivity. The technological quality was similar in all of the treatments. The treatments Compost organic, Control and Sunnhemp without compost presented Margin of Contribution Industrial fellow creatures amongst themselves and superiors to the other treatments. / Dois grandes desafios para a agroindústria canavieira são a redução do investimento e do custo operacional para aumentar a competitividade do açúcar e do etanol. A melhoria da qualidade química e física do solo no decorrer dos anos de cultivo da cana é um dos fatores que contribuem para vencer esses desafios. O objetivo deste trabalho foi de avaliar o efeito da consorciação intercalar em linha com Crotalaria juncea e Cajanus cajan na produtividade, qualidade tecnológica e na margem de contribuição industrial da soqueira de cana-de-açúcar. O experimento foi realizado em Valparaíso - SP na Usina da Barra S/A filial Univalem, utilizando o delineamento estatístico blocos completos ao acaso com quatro repetições. Os resultados demonstraram que a produtividade de colmos por hectare das leguminosas foram semelhantes à testemunha. O composto orgânico como única fonte de nutrição apresentou a maior produtividade. A qualidade tecnológica foi semelhante em todos os tratamentos. Os tratamentos Composto orgânico, Testemunha e Crotalária sem composto apresentaram Margem de Contribuição Industrial semelhantes entre si e superiores aos outros tratamentos.
446

Viabilidade de adubação da goiabeira 'Paluma' utilizando subproduto residual da indústria processadora de frutos da própria cultura /

Souza, Henrique Antunes. January 2009 (has links)
Resumo: A utilização de resíduos orgânicos, urbanos ou industriais, em áreas agrícolas pode ser justificada pela necessidade de um destino apropriado e reciclagem para esses materiais, visto que a quantidade gerada tem aumentado rapidamente com o tempo. É crescente o interesse dos governos, das instituições agronômicas e dos produtores rurais, por informações sobre o tema. A busca por novos insumos agrícolas é de muita importância para uma agricultura durável e viável. Diante disso, a utilização do subproduto da indústria de processamento de goiabas poderia substituir parcialmente a adubação mineral, tendo em vista o relativamente elevado teor de nutrientes contidos neste resíduo, diminuindo os impactos ambientais de seu acúmulo e reduzindo os custos de produção nas áreas frutícolas. Dada a escassez de informações na literatura e a importância do manejo adequado de resíduos orgânicos na agricultura, objetivou-se avaliar os efeitos da aplicação do subproduto em um Argissolo, determinando-se as alterações químicas provocadas no solo, no estado nutricional das goiabeiras e na produção de frutos. O delineamento empregado foi em blocos casualizados, com cinco tratamentos e quatro repetições, sendo as doses do subproduto (moído) iguais a: zero, 9, 18, 27 e 36 t/ha (peso seco). Foram feitas três aplicações: em 2006, 2007 e 2008. Houve incremento nas concentrações de P no solo; houve aumento dos teores foliares de N, Ca, Mg e Mn; a produção de frutos foi afetada positivamente no terceiro ano de condução do ensaio. / Abstract: The use of organic waste, urban or industrial, in agricultural areas can be justified by the need for an appropriate destination and recycling for these materials, since the amount generated has increased rapidly with time. There are growing interest from governments, institutions and farmers, for information on the subject. The search for new agricultural inputs is of great importance to make agriculture sustainable and viable. Thus, the use of residue from processing industry guavas could partially replace the mineral fertilizer, relatively high nutrients content, reducing the environmental impacts of its accumulation and reducing the production costs. Taking into account information in the literature and the importance of a suitable management of organic residue in agriculture, this research aimed to evaluate the effects of application of the residue from the guava processing industry on Ultissol, by determining the chemical changes induced in the soil, the nutritional status and production of guava fruit. The experimental design randomized blocks with four replications, and treatments correspond five doses of the residue equal to: zero, 9, 18, 27 and 36 t/ha (dry weight). Three applications were made of waste: in 2006, 2007 and 2008. The residue increased concentrations of phosphorus in the soil, the guava plants higher levels of N, Ca, Mg and Mn, the fruit production was affected positively and significantly in the third year of the experiment. / Orientador: William Natale / Coorientador: Renato de Mello Prado / Banca: Jairo Osvaldo Cazetta / Banca: José Darlan Ramos / Mestre
447

The effects of different dietary fibre levels on methane production and growth performance of Bonsmara and Nguni steers

Jiyana, Sanele Thabani 12 1900 (has links)
The aim of the study was to determine the effects of different dietary fibre levels on methane production and growth performance of Bonsmara and Nguni steers. Nine Bonsmara and nine Nguni male weaners aged 8 – 9 months were used for the study. On arrival, animals were fed Eragrostis curvula hay on ad libitum basis for the first 14 days as part of adaptation to the feedlot environment. Animals were gradually adapted to treatments to prevent metabolic disorders. The study was conducted as a 3 x 3 x 2 factorial experiment. Treatments were allocated in a completely randomised design. Data were submitted to analysis of variance (ANOVA). Student's t-LSD was calculated at the 5 % level (P < 0.05) to compare treatment means for significant effects. Feeding a diet that is low in crude fibre content had significantly increased (P < 0.05) growth performance in both breeds. Bonsmara steers had significantly higher growth performance (P < 0.0001) across all treatment diets compared to Nguni steers. High rumen total microbial count was observed in animals that received diets with low crude fibre. Reducing dietary crude fibre resulted in reduced methane production. Low dietary fibre showed low rumen archaea counts. There was a positive correlation between rumen pH and methane emission for both Bonsmara (R2 = 0.9105) and Nguni (R2 = 0.9517) steers. However, a negative correlation was observed between rumen total microbial count and feed conversion ratio for both Bonsmara (R2 = 0.8286) and Nguni (R2 = 0.7208) steers. The low rumen archaea counts were detected from the Bonsmara. Feeding diets with low fibre levels is recommended for improving growth performance and reducing methane production for Bonsmara and Nguni steers. / Agriculture and  Animal Health / M. Sc. (Agriculture)
448

Economic feasibility of anaerobic digestion of swine manure for a grower-to-finisher hog operation in Quebec

Apushev, Nurlan January 2004 (has links)
No description available.
449

Analysis of Bacterial Abundance and Species Diversity in Various Soils

Roth, McKenzie L. January 2012 (has links)
No description available.
450

An Environmental (LCA) and economic assessment (LCC) of on-farm and centralized alternatives for biogas production for two Swedish farms in Götene

Ouakrim, Abdelali January 2023 (has links)
Biogas production through anaerobic digestion is an important part towards the achievement of a bio-based and circular economy in Sweden. In fact, Swedish government proposed a strategy suggesting that biogas production should be increased from 2 TWh today to 7 TWh by 2030. Sweden has a large potential for biogas production from agricultural residues, not the least the Region Västra Götaland (RVG) where the stakeholders from the present study are located. The study explores the possibilities to use farm manure in co-digestion with deep bedding to produce biogas. The possibilities include two main alternatives for biogas production; mainly combined heat and power (CHP) to produce heat and electricity and biogas upgrading to produce bio-methane. The study took two existing organic farms in the municipality of Götene as a case study as well as an under-construction biogas plant by the company Gasum. The results of the present study also confirm that biogas could be a better option both economically and environmentally than fossil fuels. Additional results show that diesel consumption and energy prices are seen as hotspots that greatly influence both technical performance and economic profitability of biogas production. Another parameter is the geographical location of the studied system which could delimit or enhance the biogas production prospects depending on the proximity to gas grid or biogas unit. The aim of the study is to assess which of the studied alternatives is most profitable and has less environmental impacts; sending liquid manure to a biogas plant and receiving liquid fertilizer in exchange (centralized scenario) or invest in a biogas plant at the farm (on-farm scenario). A life cycle assessment (LCA) was conducted to compare environmental impacts of producing the equivalent of 1 MWh of biogas through on-farm plant and a biogas unit operated by the Finnish company Gasum. While a life cycle costing (LCC) was carried out considering a 10 year period with a 3% interest rate to analyze which of the two aforementioned options is more profitable for both farmers. Further this study aims to spur the interest of other scholars to further explore the potential of biogas/biomethane production within the agriculture sector and provide a better understanding of the different dynamics that impact the balance between energy provisions and the farm production process, and thus assist farmers to take part in the transition to a more renewable energy source.

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