High tunnels are a special type of greenhouse with primary operational goals of season extension, crop quality improvement, and new crop production opportunities to reach unique markets. From an engineering viewpoint, high tunnels have many of the same design concerns as larger, more complex greenhouses. They capitalize on the greenhouse effect as do all enclosed plant growth structures. However, less automated environmental control systems are required for the desired crop production. Tunnel designs are less complex and less expensive than large high-technology greenhouse ranges, but they must be designed and constructed with the fundamental assurance of structural stability, safety, efficient layout, appropriate environmental control, and effective crop management in mind.
Gene A. Giacomelli
Gene A. Giacomelli and William J. Roberts
The diversity of coverings for the greenhouse and other plant production structures has increased dramatically during the past 4 decades. This has resulted from the availability of new types of covering materials and enhancements of previously existing materials, as well as the demands for technological improvements within the expanding controlled environment agricultural industry. The types of coverings currently available are dominated by plastics. These range from traditional glass to the recent advent of polymer plastics, such as thin films or multilayer rigid thermoset plastic panels. Available enhancements such as ultraviolet radiation (UV) degradation inhibitors, infrared radiation (IR) absorbency, and anti-condensation drip surfaces, as well as their physical and spectral properties are discussed. The selection of specific covering alternatives has implications for the greenhouse superstructure and its enclosed crop production system.
Milton E. Tignor*, Gene A. Giacomelli, Tracy A. Irani, Chieri Kubota, Margaret J. McMahon, Sandra B. Wilson, and David A. Heleba
Currently, in the United States, the greenhouse industry covers more than 15,000 acres and is supported by a diverse number of firms with employee expertise that includes greenhouse manufacturing, engineering, irrigation, horticulture, IPM, sales, marketing, and business management. The growing greenhouse industry continues to be in need of highly trained undergraduates that have mastered an amalgam of scientific and business concepts necessary to be competitive in today's agricultural marketplace. Using a multidisciplinary approach we are creating a multimedia instrument for utilization in a variety of greenhouse related courses. This instrument ultimately will be available on the web for anyone to access. To ensure that our vision matches need, we have reviewed the courses offered throughout the United States at 1862, 1890, and 1994 land grant institutions. Course information collected includes; college, Dept., title, level, description, website (if available) and instructor e-mail (if available). Interestingly, there are at least 84 courses offering some aspect of greenhouse science in the U.S. Most are offered in Colleges of Agriculture or Engineering, but are housed in 17 diverse Dept.s. Examples include Dept.s of Horticulture; Agronomy and Horticulture; Agricultural Biosystems and Engineering; Plant, Soil, and Entomological Science; and Horticulture, Forestry, Landscape & Parks. This information will be utilized to focus the instructional design phase of the multimedia instrument, to contact current course instructors for feedback, and to frame future development of the resource.
Milton E. Tignor, Sandra B. Wilson, Gene A. Giacomelli, Chieri Kubota, Efren Fitz-Rodriguez, Tracy A. Irani, Emily B. Rhoades, and Margaret J. McMahon
Milton E. Tignor, Sandra B. Wilson, Lisa S. Hightower, Efren Fitz-Rodriguez, Gene A. Giacomelli, Chieri Kubota, Emily Rhoades, Tracy A. Irani, Margaret J. McMahon, Andrew N. Laing, David A. Heleba, and Sarah M. Greenleaf
Using a multidisciplinary approach, we are creating an instrument for utilization in a variety of greenhouse related courses. We now have over 3 hours of edited and titled video segments that were obtained at different locations by the same videographer. The greenhouse businesses in Arizona, Vermont, Ohio, and Florida were chosen due to their unique business strategies, level of computerization, type of greenhouse construction, management philosophies, and climate challenges. Individual video segments are based on nine topics that were covered at each location including computers, structure, plant life cycle, and labor. The videos have been placed on a streaming media server and will be burned to a DVD. An interactive Flash-based greenhouse environment simulator is nearly complete. This instrument allows students to model greenhouse environments based on climate data from each of the four video locations. Additionally, a searchable digital repository has been established that will allow other participants to submit materials for educational use. This open source software (DSpace) has an integrated distribution license which streamlines compliance with the Digital Millennium Copyright Act. Several hundred high quality images have already been uploaded, described and tagged. Learning assessment tools based on numerical self-evaluation and verification narratives are also being developed in conjunction with the multimedia tools. We have created a database of all the greenhouse courses at 1862, 1890, and 1994 institutions and hope to build a community of teachers that will utilize and contribute to the multimedia greenhouse collection. This community has already grown to include two international greenhouse experts who contributed interactive software for educational use.