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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.
1

High tunnels extend the growing season in warm season crops tomato, cucumber and bell pepper

Splichal, Kyla Louise January 2020 (has links)
High tunnels are used to modify the crop environment by trapping solar energy, providing protection from unfavorable weather events, and extending the growing season in temperate regions. This project assessed yield and quality in three independent cultivar trials of warm-season crops tomato (Solanum lycopersicum L.), bell pepper (Capsicum annuum L.) and cucumber (Cucumis sativus L.) grown under high tunnel production compared with an outdoor field in eastern and western North Dakota. Tomato yields in the high tunnel were increased by 1.4 times over the field trial yields. Yields from the pepper cultivar trials both inside the high tunnel and outside field were comparable to one another at 1.24 kg plant-1 and 1.06 kg plant-1, respectively. Cucumber yields in the high tunnel were increased by 1.7 times over the field trial yields. Results indicate that in North Dakota, high tunnels extended the growing season, and increased production relative to field conditions.
2

Enhancing Out-of-Season Production of Tomatoes and Lettuce Using High Tunnels

Hunter, Britney L. 01 December 2010 (has links)
The growing season for vegetable crops is limited by freezing temperatures in arid high elevation climates such as northern Utah. Logan, Utah (41.73 N, 111.83 W, 1382 m elevation) has a short, variable growing season with an average frost-free period of 135 days. Extending the growing season provides growers with an opportunity to extend revenue into a normally unproductive period and benefit from out-of-season price premiums. High tunnels have been used to effectively extend the growing season for numerous crops by providing cold temperature protection. However, limited high tunnel research has been performed in arid high elevation regions that experience extreme temperature fluctuations. The use of high tunnels was investigated in North Logan, Utah to extend the growing season for tomatoes and lettuce. In 2009 and 2010, supplemental heating under low tunnels within high tunnels was investigated to provide early season cold temperature protection for tomatoes. Sunbrite tomatoes were transplanted into four high tunnels over three planting dates. Tomatoes were subjected to supplemental heating treatments including soil warming cables alone or in conjunction with 40-watt incandescent lights for air heating. The highest early season and overall yield was achieved with the 17 Mar. planting date. Early season yield was significantly less for the latest planting date (7 Apr.) compared to the 17 Mar. and 30 Mar. planting dates. Early season yield was significantly greater for treatment plots with soil plus air heating, and soil heating alone significantly improved total yield. The use of a vertical structure within a high tunnel was investigated to improve productivity for lettuce. Parris Island Cos lettuce was consecutively transplanted from spring 2008 to spring 2010 in a high tunnel at the same site. The vertical growing system allowed for 31 plants*m-2 in south oriented gutters, and 45 plants*m-2 in east/west oriented gutters compared to 25 plants*m-2 in the ground including space for maintenance. Root zone temperatures in the gutters fluctuated widely in response to air temperatures, and super-optimal soil temperatures impeded growth. Productivity (g*m-2) in the gutters was only significantly greater than productivity in the ground soil during the spring and fall months when soil and air temperatures were not frequently below 0 °C or above 24 °C. This thesis includes both research results and extension factsheets intended for growers interested in high tunnel production of tomato and lettuce.
3

Abiotic Factors during Spring and Fall in Ohio: Their Measurement and Shaping of Lettuce Tissue Abundance and Composition

Bumgarner, Natalie Ruth 25 June 2012 (has links)
No description available.
4

Cooling Capacity Assessment of Semi-closed Greenhouses

Lee, Wee Fong 22 June 2010 (has links)
No description available.
5

Extending the Tourist Season : An In-Depth Study of Tourism Relationships and Collaborations in Åre and Visby

Dolk, Gustav, Arvidsson, Johanna January 2024 (has links)
Projektet syftar till att utforska turismsektorns dynamik med fokus på förlängning av turistsäsongen, med Åre och Visby som jämförelseobjekt. Genom en djupgående dokumentanalys och intervjuer med personer inom destinationernas turismsektor identifieras kritiska faktorer för framgångsrik och hållbar destinationsutveckling. Frågeställningarna inkluderar strategier för att attrahera turister året runt och samarbetsformer för att förlänga säsongen. Resultaten visar att båda destinationerna har unika strategier baserade på geografiska och klimatiska förutsättningar. Åre satsar på vinter och sommar och vill ses som en åretrunt-destination medan Visby arbetar med att utvidga sommarsäsongen till höst och vår. Samarbeten mellan olika aktörer, såsom kommuner och näringsliv, är avgörande för att hantera utmaningarna med lågsäsonger. Slutligen framhävs att för att vara en ledande turistdestination som Åre och Visby, krävs både strategiskt arbete för att locka turister året runt och effektiva samarbeten inom turismsektorn.  The thesis aims to explore the dynamics of the tourism sector with a focus on extending the tourist season, using Åre and Visby as comparative subjects. Through in-depth document analysis and interviews with stakeholders in the destinations' tourism sectors, critical factors for successful and sustainable destination management are identified. Key inquiries include strategies to attract tourists year-round and forms of collaboration to extend the season. The results reveal that both destinations have unique strategies based on geographical and climatic conditions. Åre focuses on winter and summer tourism, striving to be a year-round destination, while Visby aims to extend its summer season into the fall and spring. Collaborations among various stakeholders, such as municipalities and businesses, are crucial for addressing off-peak season challenges. Ultimately, it is emphasized that to be leading tourist destinations like Åre and Visby, strategic efforts to attract tourists year-round and effective collaborations within the tourism sector are essential.
6

Ett matsystem med biologiska jordbruksmetoder och växthusodling : Kost, jordbruk och energibalans i växthus / A food system with biological farming methods and greenhouse cultivation : Diet, farming and greenhouse energy balance

Norlén, Mikael January 2016 (has links)
The project examines the possibilities to develop a local and sustainable model for food production in Uppsala with focus on diet, farming methods and different types of greenhouse installations. With the simulation software VIP energy 3.1.1 the energy balance and temperature development of greenhouses of different materials were calculated for different operating cases. The results were also compared when the greenhouse was installed stand-alone or integrated to the wall of a small standard or passive house. With a starch based diet and biological farming methods research suggests it is possible to produce food efficiently without compromising the environment or our health. The yearly food needs for a family of four that follows the suggested diet was estimated to 4362 kg and the outdoor land required to produce it was calculated to 4676 m2 through organic yield statistics. The area could however be reduced to 2813 m2 if the only starch staple in production was potatoes. The tender growing season in a greenhouse constructed with a covering of 5 mm glass or 5-16Ar-5 mm was calculated to 85 and 148 days respectively. The energy use required for year round production of mushrooms in the respective greenhouses was calculated to 53 or 16 kWh/m2,year. Half hardy plants required 399 or 173 kWh/m2,year and tender plants 953 or 358 kWh/m2,year. When the greenhouses were connected to the wall of a small house the heating demand could be reduced by up to 22 % depending on the operating case.

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