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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.
51

Radiciações e frações solares UV, PAR, IV em estufa de polietileno : evolução anual média mensal diária e equações de estimativa /

Dal Pai, Enzo, 1982- January 2010 (has links)
Orientador: João Francisco Escobedo / Banca: Luiz Roberto Angelocci / Banca: Dinival Martins / Resumo: O trabalho descreve o estudo das radiações global(G), ultravioleta (UV), fotossinteticamente ativa (PAR), infravermelha (IV) e da insolação, em uma estufa de polietileno, medidas no período de março de 2008 a fevereiro de 2009 em Botucatu, São Paulo, Brasil. Foram analisados no presente estudo: 1- a evolução anual das radiações e frações solares UV/G, PAR/G e IV/G média mensal; 2- as equações de estimativa para as radiações UV, PAR e IV dentro da estufa em função das radiações global interna e global externa ; 3- evolução anual da insolação média mensal e a equação de estimativa Ångström para as radiações G, UV, PAR e IV dentro da estufa, em função da razão de insolação interna e externa. A evolução anual das radiações G, UV, PAR e IV médias mensais diárias dentro e fora da estufa, mostrou que alem do dia e local, dependem do clima, cobertura do céu, presença de vapor entre outros. As radiações foram maiores no verão-primavera e menores no outono-inverno. Os valores médios total dentro e fora da estufa foram: GIN = 13,1MJ/m2, UVIN= 0,34MJ/m2, PARIN = 6,70 MJ/m2 e IVIN = 6,15MJ/m2, GEX= 17,14MJ/m2, UVEX= 0,72MJ/m2, PAREX = 8.38 MJ/m2 e IVEX= 8.04MJ/m2. Os valores médios total, das frações em percentagem, dentro e fora da estufa foram: UVIN / GIN =2,6% ; PARIN/GIN = 50.6%, IVIN/GIN= 47,1%, UVEX / GEX = 4,18%, PAREX/GEX= 48,9% e IVEX/GEX= 46,9% respectivamente. As equações de estimativa, anual e sazonal, obtidas para as irradiações Huv, Hpar e Hiv em função da radiação HIN e HEX são lineares, tipo Y = aX, onde coeficiente angular quantifica percentualmente a fração espectral: anual HUVIN /HGIN = 2,6%; HPARIN/HGIN = 50,8% e HIVIN/HGIN = 46,7%, enquanto que a sazonal: Primavera HUVIN /HGIN = 2,5%; HPARIN/HGIN = 51,7% e HIVIN/HGIN = 45,7%; Verão: HUVIN /HGIN = 2,7%; HPARIN/HGIN = 51,8% e HIVIN/HGIN = 45,4%, ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study describes the study of the global radiation(G), ultraviolet (UV), photosynthetically active radiation (PAR), infrared radiation (IV) and insolation, inside a greenhouse of polyethylene, measures in the period of March 2008 to February of 2009 in Botucatu, São Paulo, Brazil. They had been analyzed in the present study: 1 - annual, monthly and average evolution of the radiations UV/G, PAR/G and IV/G; 2 - equations of estimate for radiations UV, PAR and IV inside of the greenhouse in function of the radiations global internal and global external; 3 - annual evolution of the monthly average insolation and Ångström equation of estimate for radiations G, UV, PAR and IV inside of the greenhouse, in function of the reason of internal and external insolation. The annual evolution of radiations G, UV, PAR and IV daily monthly averages inside and outside of the greenhouse, showed that beyond the day and place, they depend on the climate, the radiations had been bigger in the summer-spring and minors in the autumn-winter. The average values total inside and outside of the greenhouse had been: GIN = 13,1MJ/m2, UVIN= 0,34MJ/m2, PARIN =6,70 MJ/m2 and IVIN = 6,15MJ/m2, GEX= 17,14MJ/m2, UVEX= 0,72MJ/m2, PAREX = 8,38 MJ/m2 and IVEX= 8.04MJ/m2. The average values total, of the fractions in percentage, inside and outside of the greenhouse had been: UVIN/GIN =2,6%; PARIN/GIN = 50,6%, IVIN/GIN= 47,1%, UVEX/GEX = 4,18%, PAREX/GEX= 48,9% and IVEX/GEX= 46,9% respectively. The equations of estimate, annual and sazonal, gotten for the irradiations Huv, Hpar and Hiv in function of radiation HIN and HEX are linear, type Y = aX, where angular coefficient it quantifies the spectral fraction percentile: annual HUVIN /HGIN = 2,6%; HPARIN/HGIN = 50,8% and HIVIN/HGIN = 46,7%, whereas the sazonal: Spring HUVIN /HGIN = 2,5%; HPARIN/HGIN = 51,7% and HIVIN/HGIN = 45,7%; Summer: HUVIN /HGIN = 2,7%; ...(Complete abstract click electronic access below) / Mestre
52

Microclima na produÃÃo de alface hidropÃnica em ambiente protegido utilizando telas de sombreamento como subcobertura / Microclimate hydroponic lettuce production in greenhouse shading using screens as subcover

Francisco Alexandre de Lima Sales 28 March 2012 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A adequaÃÃo do microclima das estufas Ãs necessidades das culturas tornou-se um fator de suma importÃncia para o bom desenvolvimento das culturas no cultivo protegido, sendo que em determinados horÃrios as temperaturas internas se elevam podendo reduzir a fotossÃntese. Para isso, podem ser utilizadas tecnologias alternativas que adequem as temperaturas as necessidades das culturas, tais como o uso de telas de sombreamento, principalmente para a reduÃÃo da temperatura nos perÃodos mais quentes do dia. Sendo assim, o objetivo deste trabalho foi avaliar o efeito de diferentes tipos de telas de sombreamento instaladas internamente nas estufas, logo abaixo da cobertura, sobre o crescimento de duas variedades de alface do tipo crespa (Marianne e VerÃnica), em um sistema de produÃÃo hidropÃnico em NFT (TÃcnica de Fluxo Laminar). O experimento foi conduzido em estufas cobertas com filme PEBD de 150 Âm, que apresentavam os seguintes tratamentos: ambiente sem uso de tela como subcobertura (ST), ambiente com tela termorrefletora como subcobertura (TC), ambiente com tela de sombreamento preta como subcobertura (TP) e ambiente com tela vermelha como subcobertura (TV). Para avaliar a modificaÃÃo ambiental ocasionada pelo uso do filme PEBD e das telas, foram instalados, em cada estufa e no ambiente externo, termo-hidrÃmetros data loggers que registravam as variÃveis ambientais (temperatura e umidade relativa) a cada 30 minutos durante todo o perÃodo experimental. Posteriormente, foram calculados os graus dia acumulados de cada ambiente. Para analisar as alteraÃÃes nos padrÃes de resposta das plantas aos diferentes ambientes de cultivo, foram realizadas cinco coletas de plantas durante o perÃodo do experimento, sendo coletadas ao acaso, vinte plantas por tratamento. As plantas retiradas das bancadas eram repostas por outras vindas das bancadas de reposiÃÃo. ApÃs a coleta das plantas, as mesmas eram levadas ao laboratÃrio para realizaÃÃo das mediÃÃes de peso seco de raiz, caule e folhas, e da Ãrea foliar. Essas informaÃÃes foram utilizadas para estimar as variÃveis morfolÃgicas. Os resultados indicaram que o uso das telas como subcobertura afetou o ambiente no interior das estufas, principalmente a temperatura e a umidade relativa do ar, onde o uso das telas termorrefletora e preta reduziu a temperatura mÃxima em 4,7 e 3,6ÂC, respectivamente, com relaÃÃo ao ambiente que nÃo usava tela como subcobertura (ST). Em relaÃÃo ao acÃmulo de graus dia, o ambiente ST e TV apresentaram comportamentos bem similares, contudo os ambientes TC e TP apresentaram um menor acÃmulo tÃrmico em relaÃÃo a ST e TV. Quanto Ãs alteraÃÃes morfolÃgicas ocasionadas pelas modificaÃÃes ambientais foi possÃvel constatar que o uso das telas termorrefletora e preta influenciou de forma positiva o nÃmero de folhas, o nÃmero de folhas maiores que 10 cm e o Ãndice de Ãrea foliar. TambÃm foi possÃvel observar que as variÃveis, nÃmero de folhas, nÃmero de folhas maiores que 10 cm, Ãndice de Ãrea foliar, taxa de crescimento absoluto e taxa de assimilaÃÃo lÃquida ajustaram-se, com elevados Ãndices de determinaÃÃo, a uma equaÃÃo sigmoidal com trÃs parÃmetros. Enquanto que as variÃveis, razÃo de peso foliar, razÃo de Ãrea foliar, Ãrea foliar especÃfica e taxa de crescimento relativo apresentaram ajuste polinomial de 3Â grau. De modo geral, o uso das telas termorrefletora e preta proporcionou uma melhoria de alguns fatores primordiais ao comÃrcio das plantas (nÃmero de folhas maiores que 10 cm e IAF), porÃm nÃo se pode afirmar que tais condiÃÃes sejam significativas para todas as Ãpocas do ano, fazendo-se necessÃrios mais estudos em outras Ãpocas do ano. / The adequacy of the microclimate of greenhouses to the needs of crop, has become a very important factor for the proper development of protected crops, times and in certain internal temperatures rise and may reduce photosynthesis.For this alternative technologies can be used to suit the needs of temperatures cultures, such as the use of shading screens, particularly for reducing the temperature in the warmer periods of the day. Therefore, the objective of this study was to evaluate the effect of different types of shading screens installed inside the greenhouses, just below the roof, on the growth of two varieties of lettuce crisp (Marianne and Veronica), in a production system in NFT hydroponic (Laminar Flow Technique). The experiment was conducted in greenhouses covered with LDPE film of 150 micron, which had the following treatments: environment without using the screen as undercoverage (ST), ambient thermal reflector screen as undercoverage (TC), Environment shade cloth as black undercoverage (TP) and environment as undercoverage red screen (TV). To assess the environmental changes caused by the use of LDPE film and screens were installed in each greenhouse and an outdoor thermo-hygrometer data loggers that recorded the environmental variables (temperature and relative humidity) every 30 minutes throughout the period of Experimental. Subsequently, we calculated the accumulated degree days for each environment. To analyze changes in patterns of plant response to different environmental conditions, there were five samplings during the experiment, and randomly collected twenty plants per treatment. The plants were removed from the benches replaced by others coming from the stands replacement. After collecting the plants, they were brought to the laboratory for measurement of dry weight of root, stem and leaves, and leaf area. This information was used for estimating of variable morphological. The results indicated that the use of screens as undercoverage affected the environment inside the greenhouse, especially temperature and relative humidity, where the use of thermal reflector and black screens reduced the maximum temperature at 4.7 and 3.6 Â C, respectively, with the environment that was not on screen as undercoverage (ST). Regarding the accumulation of degree days, the environment and TV ST showed very similar behavior, however environments CT and VT had a lower thermal accumulation in relation to TS and TV. As for the morphological changes caused by environmental changes, we determined that the use of thermal reflector screens and black influenced, positively, the number of leaves, leaf number larger than 10 cm and the leaf area index. It was also observed that the variables, number of leaves, leaf number larger than 10 cm, leaf area index, absolute growth rate and net assimilation rate were adjusted, with high levels of determination, a sigmoidal equation with three parameters. While the variables, leaf weight, leaf area ratio, specific leaf area and relative growth rate showed a better fit 3rd degree polynomial. In general, the use of thermal reflector and black screens provided an improvement of some key factors to trade in plants (number of leaves greater than 10 cm and LAI), however, it is not possible to say that these conditions are significant for all seasons , making it necessary more study at other times of the year.
53

Efeitos de três lâminas de irrigação e de quatro doses de potássio via fertirrigação no meloeiro em ambiente protegido. / Effect of three irrigation water depths and four potassium levels applied by fertigation on melon crop under protected environment.

Adriano José Soares 29 January 2002 (has links)
Este trabalho teve como objetivo estudar os efeitos de três lâminas de irrigação e de quatro doses de potássio aplicadas via água de irrigação por gotejamento na produtividade e na qualidade dos frutos de melão (Cucumis melo L.), cv. Dom Carlos, com espaçamento de 1,2 m x 0,4 m. Visa também determinar os níveis de irrigação e as doses de potássio mais adequados para o meloeiro, cultivado sob fertirrigação em ambiente protegido no período de outono-inverno. O experimento foi realizado no período de abril/2000 à julho/2000 no Departamento de Engenharia Rural da ESALQ/USP. Foi utilizado delineamento experimental inteiramente casualizado com três repetições, em esquema fatorial 4 x 3. Os tratamentos resultam da combinação de três lâminas de irrigação(L1=50% Etc, L2= 75% ETc e L3=100% da ETc) e de quatro doses de potássio (K1=30; K2=90; K3=150 e K4=210 kg de K2O há -1 ). A fertirrigação foi realizada a cada dois dias, utilizando-se tanques onde os fertilizantes eram dissolvidos na água de irrigação. O monitoramento da umidade do solo foi feito com tensiômetros instalados em torno da planta; pelos valores de potencial mátrico, a lâmina de irrigação L3 manteve o perfil de distribuição de água mais constante do que os de L1 e L2. As produtividades, comercial , não comercial e total, foram influenciadas pelos níveis de irrigação, pelas doses de potássio e pela interação entre eles, sendo as maiores produtividades totais de 29,7 e 27 t ha -1, obtidas com as combinações de 150 kg de K2O ha -1 e 105 L planta -1 ciclo -1 (K3L2) e 150 kg de K2O ha -1 e 140 L por planta por ciclo (K3L3), respectivamente. Já as maiores produtividades comerciais foram 12,6 e 10 t ha -1, obtidas com as combinações 30 kg de K2O ha -1 e 105 L planta -1 ciclo -1 (K1L2) e 210 kg de K2O ha -1 e 140 L planta -1 ciclo -1 (K4L3), respectivamente. / The objective of this work was to study the effects of irrigation water depths and potassium levels applied by drip irrigation on yield and fruit quality of melon (Cucumis melo L.), cv. Dom Carlos, spaced 1,2 m x 0,4 m between rows and plants, respectively, and to determine the irrigation depths and potassium levels most suitable for fertigated melon cultivated in a greenhouse in the autumn-summer season. The trial was accomplished from april/2000 to june/2000 at the Departamento de Engenharia Rural of ESALQ/USP. The treatments were completely randomized with three replications in a factorial scheme 4 x 3, and resulted from a combination of three irrigation water depths (L1=50% ETc, L2=75% ETc and L3=100% ETc) and four potassium levels (K1=1,45; K2=4,35; K3=7,25 and K4=10,15 g of K2O plant -1 season -1 ). Fertigation was taken every two days using tanks where fertilizers were dissolved in the irrigation water. Soil moisture monitoring was made by tensiometers installed around the plant. From the matric potential values, the irrigation depth L3 maintained the water distribution pattern more constant than the L1 and L2. The marketable, non-marketable and total yields were modified by the irrigation depths, potassium levels and their interaction, with the higher total yields (29.7 and 27.0 ton ha -1 ) obtained with the combination of 150 kg K2O ha -1 and 105 L plant -1 season -1 (K3L2) and 150 kg K2O ha -1 and 140 L plant -1 season -1 (K3L3), respectively. The higher marketable yields were 12.6 and 10.0 ton ha -1 , obtained with the combinations of 30 kg K2O ha -1 and 105 L plant -1 season -1 (K1L2) and 210 kg K2O ha -1 and 140 L plant -1 season -1 (K4L3), respectively. Fruits' physical and chemical parameters evaluated are in agreement with that demanded by market.
54

Analysis of energy efficient heat and lighting systems in a subarctic greenhouse

Sigvardsson, William January 2023 (has links)
This report studies a subarctic greenhouse located in Nikkala, Sweden called Nikkala handelsträdgård. Through a visit to the greenhouse coupled with the creation of two simulation models this study investigates the differences in energy demand with water-carried and air-carried heating systems, high pressure sodium lights and Light emitting diode lights and insulation in parts of the greenhouse without a active cultivation. With the purpose of comparing the alternatives to the existing system at Nikkala handelsträdgård. This, to evaluate if an investment in insulation for the non cultivating parts or changing to a water-carried heating system with Light emitting diode lights could be considered profitable. Operating a greenhouse in a subarctic climate is a hard task and especially if the operation is year round. Efficient heating systems, thermal screens, dehumidifying measures and Lighting systems are crucial to ensure a profitable business. At Nikkala handelsträdgård they are currently using a pellets burner in combination with a air-carried heating system and HPS lamps in the majority of the greenhouse.  The simulations of the main greenhouse were made in Ansys fluent where the crop section was simulated by implementing source terms to a macro porous medium. The parts of the greenhouse which did not host an active cultivation were simulated in IDA ICE.  It was found that saving of just under 14 800 SEK monthly or 18 % could be made by implementing a water-carried heating system in combination with state of the art lighting. Given this a payback-time of 3-9 years could be expected given different scenarios. An implementation of insulation in the non cultivation greenhouse parts would save up to 25 300 SEK annually or 46 % of the heat demand and the investment would give a payback-time of 1-2 years given different scenarios. Given this a reduction of CO2 equivalents of just under 1,9 tonnes could be achieved yearly. It was concluded that relatively inexpensive investments could have a great impact on the energy demand and thereby the economical performance of a subarctic greenhouse. New operations should be built with a LED light system and water-carried heating system and all parts of the greenhouse which is not housing an active cultivation needs to be insulated.
55

Ecology and Management of Pythium species in Float Greenhouse Tobacco Transplant Production

Zhang, Xuemei 07 January 2021 (has links)
Pythium diseases are common in the greenhouse production of tobacco transplants and can cause up to 70% seedling loss in hydroponic (float-bed) greenhouses. However, the symptoms and consequences of Pythium diseases are often variable among these greenhouses. A tobacco transplant greenhouse survey was conducted in 2017 in order to investigate the sources of this variability, especially the composition and distribution of Pythium communities within greenhouses. The survey revealed twelve Pythium species. Approximately 80% of the surveyed greenhouses harbored Pythium in at least one of four sites within the greenhouse, including the center walkway, weeds, but especially bay water and tobacco seedlings. Pythium dissotocum, followed by P. myriotylum, were the most common species. Pythium myriotylum, P. coloratum, and P. dissotocum were aggressive pathogens that suppressed seed germination and caused root rot, stunting, foliar chlorosis, and death of tobacco seedlings. Pythium aristosporum, P. porphyrae, P. torulosum, P. inflatum, P. irregulare, P. catenulatum, and a different isolate of P. dissotocum, were weak pathogens, causing root symptoms without affecting the upper part of tobacco seedlings. Pythium adhaerens, P. attrantheridium, and P. pectinolyticum did not affect tobacco seeds or seedlings. The consequences of Pythium infection were more likely to be severe when they occurred during seed germination than at seedling emergence, or after plant stem elongation when seedling roots had started to grow into underlying nutrient solutions, depending on the species of Pythium. High and low variation was observed among isolates of P. dissotocum and P. myriotylum, respectively. Pythium myriotylum co-existed with multiple other Pythium or oomycete species in the same environments within tobacco greenhouses, and significant in vitro and/or in vivo interactions between P. myriotylum and some naturally co-existing species were revealed. Pythium porphyrae may have the potential to protect tobacco seeds and seedlings from P. myriotylum infection. Greenhouse Pythium control trials identified ethaboxam, mefenoxam, and copper ionization as potentially promising alternatives to etridiazole for Pythium disease management in tobacco transplant production. The outcomes of this project provide useful new information to better understand the composition, distribution, and diversity of Pythium communities in tobacco transplant greenhouses and to improve Pythium disease management for tobacco transplant production. / Doctor of Philosophy / Pythium diseases are common in tobacco transplant production and can cause up to 70% seedling losses in hydroponic (float-bed) tobacco transplant greenhouses. However, little is known about the composition and distribution of Pythium communities in tobacco transplant greenhouses. This project began with a tobacco transplant greenhouse survey, in which 12 Pythium species were recovered from center walkways, weeds, greenhouse bay water, and tobacco seedlings. Pythium dissotocum and P. myriotylum were the two types (species) of Pythium most commonly found in the survey. Pythium myriotylum, P. coloratum, and P. dissotocum were aggressive pathogens that suppressed seed germination and caused root rot, stunting, foliar chlorosis, and death of tobacco seedlings. Pythium aristosporum, P. porphyrae, P. torulosum, P. inflatum, P. irregulare, P. catenulatum, and an isolate of P. dissotocum, were weak pathogens causing root symptoms without affecting the upper part of tobacco seedlings. Pythium adhaerens, P. attrantheridium, and P. pectinolyticum did not affect tobacco seeds or seedlings. The symptoms caused by infection by Pythium species differed among host (tobacco) growth stages, except for the most aggressive species, P. myriotylum. High levels of variation were observed among isolates of P. dissotocum, in terms of vegetative growth rate (on V8 agar media) and aggressiveness on tobacco seed and seedlings. Pythium myriotylum was found to co-exist with multiple other Pythium or oomycete species (neighbor isolates) in the same environments within tobacco greenhouses. Significant interactions between P. myriotylum and some neighbor isolates were revealed, and these interactions significantly affect the consequences of P. myriotylum infection of tobacco seeds. Greenhouse Pythium control trials identified two chemical water treatments (ethaboxam and mefenoxam), and a non-chemical water treatment (copper ionization) as potentially promising alternatives to the current standard Pythium control (etridiazole) for Pythium disease management in tobacco transplant production. The outcomes of this project provide useful new information to both better understand the composition, distribution, and diversity of Pythium communities in tobacco transplant greenhouses and to improve Pythium disease management for tobacco transplant production.
56

Water born cooling of closed greenhouses : An enclosed vertical water curtain cooling system

Kamal, Ahmad January 2022 (has links)
The greenhouses play a key role in food sustainable production, the purpose of the greenhouses is to make an artificial suitable environment to grow different kinds of plants. The cost of energy used in the greenhouses to ensure the optimum temperature, humidity, and CO2 concentration, makes up a large part of the final cost of food. Due to global warming, the successive energy crises, and the food crises, the need to make the greenhouses more energy efficient and to utilize renewable energy resources is rapidly increasing. The enclosed water curtain cooling system meets the special requirement of the greenhouse cooling system, and it has potential energy savings when it is integrated with other systems such as heat pumps, underground water sources, and surplus heat energy recovery. This system involves two special nylon foils, and a thin layer of water flows between the two foils, the two foils will be stuck to eachother by the cohesive force of the water-detergent mixture, the detergent was added to decrease the water surface tension and ensure the even distribution of the water-detergent mixture over the nylon foils. In this study, an experimental model of the enclosed water curtain was made and two sets of tests were conducted, the first set was at room temperature around 20°C, and the second test was at room temperature around 25.7 °C with an electrical heater, each set contains three tests to measure the cooling capacity of the curtain, and each test takes 2 minutes, the curtain dimensions were height and width of 1.04 m and 1.20 m respectively. By measuring the difference between the average inlet and outlet temperature of the water-detergent mixture before and after the curtain, and the mixture mass flow rate during the test period, the cooling capacityof the curtain was calculated using the energy balance equation.It was found that the curtain cooling capacity increases with the increase of ambient temperature, The large heat transfer area of the curtain which allows using higher water temperature for cooling, and the useful features of the water membrane like the high absorption of the wavelength of infrared and the high transparency of the wavelength of visible light, make this system meets the special requirements of the greenhouses cooling system. However, to be able to apply this system in real-life, the design of the curtain should be improved, and suitable materials should be chosen to make it more reliable. Also, All tests in this study were conducted in the workshop in the absence of solar radiation, therefore, the actual performance of the curtain needs to be evaluated with the presence of solar radiation, to be able to study the effects of the direct and diffuse solar radiation with various spectrum range.
57

An Economic Impact Assessment of the Green Industry of Virginia

Coppedge, Emily Jean 03 August 2004 (has links)
An analysis of the green industry of Virginia was completed in the year 2002 using a mail survey sent to industry participants. The survey was conducted by the Virginia Agricultural Statistics Service (VASS). This data was used to run an economic impact analysis of the industry using IMPLAN Professional software. Additionally, the software was used to determine the approximate affects of drought and water restrictions on the green industry. VASS received a total of 1,146 surveys for a response rate of approximately 27%. Of these responses, 42 surveys indicated that they plan to have future green industry sales but were not presently involved in the business. Another 525 responses claimed to be no longer actively involved in the industry. Therefore, the actual response rate was much closer to 15%. This necessitated the use of numerous alternative data sources to create a more complete model representation of the green industry as a whole. Two separate model scenarios were created, the first using purely survey response data, the second including data from additional sources and factoring out for possible double-counting errors. Direct employment generated from the industry was predicted to be between 29 and 36 thousand jobs, depending on which model scenario is consulted. The total economic impacts predicted from the different models are $2.03 billion and $2.41 billion, respectively. The analysis of the affects of drought and water restrictions predicted a decrease in overall impacts by 33% and 23%, respectively. / Master of Science
58

Efeito da aplicação de CO2 na água de irrigação em diferentes fases fenológicas da cultura do melão (Cucumis melo L. var. Reticulatus) cultivado em ambiente protegido. / Effect of co2 application through irrigation water at different crop stages in melon (Cucumis melo L. VAR. Reticulatus) planted in greenhouse.

d'Albuquerque Junior, Boanerges Siqueira 27 January 2004 (has links)
Sabe-se que nos últimos 100 anos a concentração de CO2 na atmosfera vem aumentando devido ao aumento da atividade do homem em emitir mais de 8 bilhões de toneladas anuais de gás carbônico. Pensando no que isso poderia representar para as plantas, nas últimas décadas se intens ificaram os estudos com aplicação de CO2 nas plantas via ambiente e via água. Freqüentemente foram observados aumentos em crescimento de produção sob elevadas concentrações de CO2 na atmosférica. O melão tem se constituído em ótimo negócio para o Nordeste brasileiro. O Brasil passou a destacar-se no cenário internacional, embora com registros de quedas nas exportações nos últimos anos. Procurando-se melhorar os estudos com aplicação gás carbônico CO2 com o intuito de torna viável a aplicação, ou seja, diminuir a relação Custo/Benefício procurou-se diminuir número de aplicações e o volume de CO2 por ha -1 mantendo-se a produtividade daquelas aplicadas durante todo o ciclo. O objetivo deste trabalho foi estudar o efeito de uma dose de (CO2) em diferentes fases fenológico da cultura do melão aplicadas via água de irrigação por gotejamento subsuperficial, na, qualidade, produtividade, do meloeiro cultivado em ambiente protegido. Para isso, foi conduzido um experimento em duas estufas de 112 m 2 cada, estudando-se o efeito na aplicação de CO2 aplicada via água de irrigação no florescimento, na frutificação e no florescimento mais frutificação, além de uma testemunha na qual não houve aplicação de CO2. O delineamento experimental para o efeito das épocas foi o de blocos casualizados , com quatro repetições. A irrigação foi realizada utilizando-se o sistema de irrigação por gotejamento, sendo estes enterrados a 15cm de profundidade, e manejados por tensiômetros. A aplicação do gás foi realizada por intermédio de um cilindro de CO2 comercial e injetadas por diferença de pressão, durante o tempo necessário à aplicação da dose pré-estabelecida. Os resultados obtidos revelaram que a aplicação de CO2 via água de irrigação para os tratamentos na frutificação (T3) e florescimento (T1) proporcionou aumentos de 18%,17% em relação ao tratamento sem CO2 (T4), o menor incremento foi de 8,8% do T2 em relação ao T4. / It is known that in the last 100 years the carbon dioxide (CO2) concentration in the atmosphere is increasing due to the increase in human activity in emitting more than eight million tons yearly of carbon dioxide. Thinking on what this could mean for plants, studies had intensified in the last decades with CO2 application to plants through environment and water. Freq uently, increases in yield were observed under high CO2 concentration at atmosphere. Melon is turning into a big business for the northeast of Brazil. Brazil starts to stand out at the international scenery, beside records of export dropping in the last years. Trying to improve the studies with CO2 application, to minimize the cost benefit relationship and this way make it viable economically by diminishing the number of application and volume of CO2 per hectare maintaining the yield obtained by those applied through out year. The objective of this work was to study the effect of one single rate of CO2 applied at different crop stages through water by a subsurface drip irrigation system, at the yield and quality, of melon cultivated in greenhouse. For that, an experiment was led in two greenhouses of 112 m 2 each, being studied the effect of CO2 applied at flowering, at fruiting, and at flowering plus fruiting, besides an untreated plot with no application of CO2. The experimental design was for timing was randomized blocks with four replications. Irrigation was realized by a subsurface dripping irrigation system, which was positioned at 15 cm depth, and managed by tensionmeters. The CO2 injection, was provided by a commercial cylinder, and was done by pressure differential. Application time was that one the necessary time to apply the pre -established rate. Obtained data showed that the application of CO2 through irrigation water for the fruiting (T3) and flowering (T1) treatments provided yield increases of 18% and 17% respectively when compared to untreated (T4), the lowest yield increment was obtained by flowering plus fruiting (T2) compared to untreated.
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Interaction between greenhouse grown chrysanthemum and Frankliniella occidentalis : a modelling approach /

Nothnagl, Margit, January 2006 (has links) (PDF)
Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv., 2006. / Härtill 5 uppsatser.
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Microclima na produção de alface hidropônica em ambiente protegido utilizando telas de sombreamento como subcobertura / Microclimate hydroponic lettuce production in greenhouse shading using screens as subcover

Sales, Francisco Alexandre de Lima January 2012 (has links)
SALES, Francisco Alexandre de Lima. Microclima na produção de alface hidropônica em ambiente protegido utilizando telas de sombreamento como subcobertura. 2012. 95 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2012. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-30T12:59:34Z No. of bitstreams: 1 2012_dis_falsales.pdf: 1966477 bytes, checksum: c3c95147261d4aba1b9c5326c3aae021 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-30T13:00:33Z (GMT) No. of bitstreams: 1 2012_dis_falsales.pdf: 1966477 bytes, checksum: c3c95147261d4aba1b9c5326c3aae021 (MD5) / Made available in DSpace on 2016-06-30T13:00:33Z (GMT). No. of bitstreams: 1 2012_dis_falsales.pdf: 1966477 bytes, checksum: c3c95147261d4aba1b9c5326c3aae021 (MD5) Previous issue date: 2012 / The adequacy of the microclimate of greenhouses to the needs of crop, has become a very important factor for the proper development of protected crops, times and in certain internal temperatures rise and may reduce photosynthesis.For this alternative technologies can be used to suit the needs of temperatures cultures, such as the use of shading screens, particularly for reducing the temperature in the warmer periods of the day. Therefore, the objective of this study was to evaluate the effect of different types of shading screens installed inside the greenhouses, just below the roof, on the growth of two varieties of lettuce crisp (Marianne and Veronica), in a production system in NFT hydroponic (Laminar Flow Technique). The experiment was conducted in greenhouses covered with LDPE film of 150 micron, which had the following treatments: environment without using the screen as undercoverage (ST), ambient thermal reflector screen as undercoverage (TC), Environment shade cloth as black undercoverage (TP) and environment as undercoverage red screen (TV). To assess the environmental changes caused by the use of LDPE film and screens were installed in each greenhouse and an outdoor thermo-hygrometer data loggers that recorded the environmental variables (temperature and relative humidity) every 30 minutes throughout the period of Experimental. Subsequently, we calculated the accumulated degree days for each environment. To analyze changes in patterns of plant response to different environmental conditions, there were five samplings during the experiment, and randomly collected twenty plants per treatment. The plants were removed from the benches replaced by others coming from the stands replacement. After collecting the plants, they were brought to the laboratory for measurement of dry weight of root, stem and leaves, and leaf area. This information was used for estimating of variable morphological. The results indicated that the use of screens as undercoverage affected the environment inside the greenhouse, especially temperature and relative humidity, where the use of thermal reflector and black screens reduced the maximum temperature at 4.7 and 3.6 ° C, respectively, with the environment that was not on screen as undercoverage (ST). Regarding the accumulation of degree days, the environment and TV ST showed very similar behavior, however environments CT and VT had a lower thermal accumulation in relation to TS and TV. As for the morphological changes caused by environmental changes, we determined that the use of thermal reflector screens and black influenced, positively, the number of leaves, leaf number larger than 10 cm and the leaf area index. It was also observed that the variables, number of leaves, leaf number larger than 10 cm, leaf area index, absolute growth rate and net assimilation rate were adjusted, with high levels of determination, a sigmoidal equation with three parameters. While the variables, leaf weight, leaf area ratio, specific leaf area and relative growth rate showed a better fit 3rd degree polynomial. In general, the use of thermal reflector and black screens provided an improvement of some key factors to trade in plants (number of leaves greater than 10 cm and LAI), however, it is not possible to say that these conditions are significant for all seasons , making it necessary more study at other times of the year. / A adequação do microclima das estufas às necessidades das culturas tornou-se um fator de suma importância para o bom desenvolvimento das culturas no cultivo protegido, sendo que em determinados horários as temperaturas internas se elevam podendo reduzir a fotossíntese. Para isso, podem ser utilizadas tecnologias alternativas que adequem as temperaturas as necessidades das culturas, tais como o uso de telas de sombreamento, principalmente para a redução da temperatura nos períodos mais quentes do dia. Sendo assim, o objetivo deste trabalho foi avaliar o efeito de diferentes tipos de telas de sombreamento instaladas internamente nas estufas, logo abaixo da cobertura, sobre o crescimento de duas variedades de alface do tipo crespa (Marianne e Verônica), em um sistema de produção hidropônico em NFT (Técnica de Fluxo Laminar). O experimento foi conduzido em estufas cobertas com filme PEBD de 150 µm, que apresentavam os seguintes tratamentos: ambiente sem uso de tela como subcobertura (ST), ambiente com tela termorrefletora como subcobertura (TC), ambiente com tela de sombreamento preta como subcobertura (TP) e ambiente com tela vermelha como subcobertura (TV). Para avaliar a modificação ambiental ocasionada pelo uso do filme PEBD e das telas, foram instalados, em cada estufa e no ambiente externo, termo-hidrômetros data loggers que registravam as variáveis ambientais (temperatura e umidade relativa) a cada 30 minutos durante todo o período experimental. Posteriormente, foram calculados os graus dia acumulados de cada ambiente. Para analisar as alterações nos padrões de resposta das plantas aos diferentes ambientes de cultivo, foram realizadas cinco coletas de plantas durante o período do experimento, sendo coletadas ao acaso, vinte plantas por tratamento. As plantas retiradas das bancadas eram repostas por outras vindas das bancadas de reposição. Após a coleta das plantas, as mesmas eram levadas ao laboratório para realização das medições de peso seco de raiz, caule e folhas, e da área foliar. Essas informações foram utilizadas para estimar as variáveis morfológicas. Os resultados indicaram que o uso das telas como subcobertura afetou o ambiente no interior das estufas, principalmente a temperatura e a umidade relativa do ar, onde o uso das telas termorrefletora e preta reduziu a temperatura máxima em 4,7 e 3,6ºC, respectivamente, com relação ao ambiente que não usava tela como subcobertura (ST). Em relação ao acúmulo de graus dia, o ambiente ST e TV apresentaram comportamentos bem similares, contudo os ambientes TC e TP apresentaram um menor acúmulo térmico em relação a ST e TV. Quanto às alterações morfológicas ocasionadas pelas modificações ambientais foi possível constatar que o uso das telas termorrefletora e preta influenciou de forma positiva o número de folhas, o número de folhas maiores que 10 cm e o índice de área foliar. Também foi possível observar que as variáveis, número de folhas, número de folhas maiores que 10 cm, índice de área foliar, taxa de crescimento absoluto e taxa de assimilação líquida ajustaram-se, com elevados índices de determinação, a uma equação sigmoidal com três parâmetros. Enquanto que as variáveis, razão de peso foliar, razão de área foliar, área foliar específica e taxa de crescimento relativo apresentaram ajuste polinomial de 3º grau. De modo geral, o uso das telas termorrefletora e preta proporcionou uma melhoria de alguns fatores primordiais ao comércio das plantas (número de folhas maiores que 10 cm e IAF), porém não se pode afirmar que tais condições sejam significativas para todas as épocas do ano, fazendo-se necessários mais estudos em outras épocas do ano.

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