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

Características quantitativas e qualitativas do capim-mombaça, submetido a doses crescentes de nitrogênio em clima tropical úmido – classificação AF

OLIVEIRA, Joelma Kyone Silva de 29 February 2016 (has links)
Submitted by Cássio da Cruz Nogueira (cassionogueirakk@gmail.com) on 2017-05-15T16:04:36Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_CaracteristicasQuantitativasQualitativas.PDF: 1827921 bytes, checksum: 280b50e3d6554eb8718b27a519046ac4 (MD5) / Approved for entry into archive by Edisangela Bastos (edisangela@ufpa.br) on 2017-05-18T12:42:50Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_CaracteristicasQuantitativasQualitativas.PDF: 1827921 bytes, checksum: 280b50e3d6554eb8718b27a519046ac4 (MD5) / Made available in DSpace on 2017-05-18T12:42:50Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_CaracteristicasQuantitativasQualitativas.PDF: 1827921 bytes, checksum: 280b50e3d6554eb8718b27a519046ac4 (MD5) Previous issue date: 2016-02-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A cadeia produtiva de ruminantes no norte do Brasil tem sua base sustentada por forragens, sendo então seu manejo e fertilização, garantindo a perenidade das gramíneas, de fundamental importância para a produção final de proteína de alto valor biológico para consumo humano. Objetivamos avaliar as características do Panicum maximum cv. Mombaça fertilizado com doses crescentes doses de nitrogênio em condições climáticas Af, sendo uma condição caracterizada por precipitação pluviométrica frequente em todos os meses do ano, ou seja, ausência de uma estacionalidade no regime de chuvas. Foram avaliadas características produtivas, morfogênicas, estruturais e químicas do capim-Mombaça em parcelas, sendo o experimento delineado em blocos ao acaso com seis tratamentos (0, 10, 20, 30, 40 e 50 kg de N ha-1 aplicação-1), cada aplicação realizada após cada corte e quatro repetições, uma repetição por bloco perfazendo um total de 24 parcelas e o corte feito a uma altura de resíduo de 40 cm, sempre que a altura média da parcela atingia 90 cm por ser considerada a altura em que o dossel intercepta 95% da luz incidente. Os dados foram submetidos à análise de variância e de regressão, a significância empregada foi de 5% dos coeficientes linear e quadrático e no coeficiente de determinação. A adubação nitrogenada afetou (p<0,05) taxas de alongamento, aparecimento, número de folhas vivas por perfilhos e a produção de massa seca do capim-Mombaça. A qualidade da forrageira também foi afetada pelas doses de N (p<0,05), sendo os teores de PB influenciados positivamente e os valores de CT negativamente. Os teores de fibra e lignina não foram influenciados pela fertilização (p<0,05), sendo um resultado positivo do ponto de vista nutricional da forragem, já que altos teores de fibra e lignina não favorecem o consumo e limitam a digestão. O nitrogênio proporciona melhores resultados quantitativos e qualitativos para capim-Mombaça em regiões de clima tropical. / The productive chain of ruminant in northern Brazil has its base sustained by forages being its management and fertilization, grasses perpetuity, extremely important for the high biological value protein final production for human intake. The study aimed to evaluate trades of Panicum maximum cv. Mombaça fertilized with increasing doses of nitrogen at Af weather conditions being this condition classified by frequent rainfall along every month of the year, so, showing no seasonality in rain scheme. There were evaluate productive trades, morphogenetic, structural and chemical of Mombaça grass in parcels. Being the experiment outlined in random blocks with six treatments (0, 10, 20, 30, 40 e 50 kg of N ha-1 aplication-1), each application performed after each cut and four repetitions, a repetition by block totalizing 24 plots and the cut done at a height of 40 cm, whenever the parcels high achieved 90 cm to be considered the time when the canopy intercepts 95% of incident light. The data were submitted to variance and regression analysis, with significance of 5% taken from the linear and quadratic coefficients of determination. Nitrogen fertilization affected (p<0,05) stretching rates, appearance, number of leaves alive by tillers and dry mass production. The forage quality was also affected by N doses (p<0,05), being the levels of CP positively affected and values of TC negatively. The fiber levels and lignin were not influenced by fertilization (p<0,05) being this result positive from the forage nutritional pint of view, once fiber and lignin high levels do not benefit consumption and cause a digestive limitation. The nitrogen provides better qualitative and quantitative results to Mombaça grass in tropical climate areas.
162

Vegetationsgeschichtliche und archäobotanische Untersuchungen zur Landwirtschaft und Umwelt im Bereich der prähistorischen Siedlungen bei Rullstorf, Ldkr. Lüneburg / Pollen analytical and archaeobotanical studies in agriculture and landscape development at the prehistoric settlements near Rullstorf, Northeast Lower Saxony

Kirleis, Wiebke 18 June 2002 (has links)
No description available.
163

Analysis and Simulation of Switchgrass Harvest Systems for Large-scale Biofuel Production

McCullough, Devita 25 January 2013 (has links)
In the United States, the Energy Independence and Security Act of 2007 mandates the annual production of 136 billion liters of renewable fuel in the US by 2022 (US Congress, 2007). As the nation moves towards energy independence, it is critical to address the current challenges associated with large-scale biofuel production. The biomass logistics network considered consists of three core operations: farmgate operations, highway-hauling operations, and receiving facility operations. To date, decision-making has been limited in post-production management (harvesting, in-field hauling, and storage) in farmgate operations. In this thesis, we study the impacts in the logistics network resulting from the selection of one of four harvest scenarios. A simulation model was developed, which simulated the harvest and filling of a Satellite Storage Location (SSL), using conventional hay harvest equipment, specifically, a round baler. The model evaluated the impacts of four harvest scenarios (ranging from short, October-December, to extended, July-March), on baler equipment requirements, baler utilization, and the storage capacity requirements of round bales, across a harvest production region. The production region selected for this study encompassed a 32-km radius surrounding a hypothetical bio-crude plant in Gretna, VA, and considered 141 optimally selected SSLs. The production region was divided into 6 sub-regions (i.e. tours). The total production region consisted of 15,438 ha and 682 fields. The fields ranged in size from 6 to 156 ha. Of the four scenarios examined in the analysis, each displayed similar trends across the six tours. Variations in the baler requirements that were observed among the tours resulted from variability in field size distribution, field to baler allocations, and total production area. The available work hours were found to have a significant impact on the resource requirements to fulfill harvest operations and resource requirements were greatly reduced when harvest operations were extended throughout the 9-month harvest season. Beginning harvest in July and extending harvest through March resulted in reductions in round balers ranging from 50-63%, as compared to the short harvest scenario, on a sub-regional basis. On a regional basis, beginning harvest in July and extending harvest through March resulted in baler reductions up to 58.2%, as compared to the short harvest scenario. For a 9-month harvest, harvesting approximately 50% of total switchgrass harvest in July-September, as compared to harvesting approximately 50% in October-December, resulted in reductions in round balers ranging from 33.3- 43.5%. An extended (9-month) harvest resulted in the lowest annual baler requirements, and on average lower baler utilization rates. The reduced harvest scenarios, when compared to the extended harvest scenarios, resulted in a significant increase in the number of annual balers required for harvest operations. However, among the reduced harvest scenarios (i.e. Scenario 3 and 4), the number of annual balers required for harvest operations showed significantly less variation than between the extended harvest scenarios (i.e. Scenarios 1 and 2). As a result, an increased utilization of the balers in the system, short harvest scenarios resulted in the highest average baler utilization rates. Storage capacity requirements were however found to be greater for short harvest scenarios. For the reduced harvest scenario, employing an October-December harvest window, approximately 50% of harvest was completed by the end of October, and 100% of total harvest was completed by the third month of harvest (i.e. December). / Master of Science
164

Fuel Yield Potential of Field Grown Agave americana L. Based on Water Soluble Carbohydrates, Acid Extractable Carbohydrates, and Enzymatic Digestibility Compared to Other Advanced Biofuel Feedstocks

Jones, Alexander M. 19 September 2017 (has links)
No description available.

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