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
Christopher Y. Choi and Gene Giacomelli
Newly formulated aqueous foam was tested in the field. The foam demonstrated the longevity necessary for practical field use. Soil temperatures beneath an insulation layer of aqueous foam were measured to determine the effectiveness of foam as soil mulch. Leaf temperature within a canopy was monitored to observe the modification of plant leaf temperature, and to evaluate the phytotoxic effects of foam applied directly to the leaf canopy. Leaves were not damaged after being covered with the foam for two weeks. The foam-protected soil was effectively insulated, and the aqueous foam proved to be an effective radiation shield against the cold night sky. Temperature differences as high as 5 °C (9 °F) were measured between the foam-covered and uncovered copper metal plates, which were used to simulate plant leaves. The foam covered plates were ≈80% as effective as the aluminum foil covered plates in reducing radiation heat transfer.
Christopher Y. Choi, Werner Zimmt, and Gene Giacomelli
Aqueous foam was developed to serve as a barrier to conductive, convective, and radiative heat transfer. Through the use of a bulking agent, the physical properties of gelatin-based foam were more stable, adhesive, biodegradable, and long lasting. The phytotoxicity, possible environmental hazard and removal of the foam were also considered. Resistance to freezing-thawing, heating-evaporation, and wind were evaluated. Studies to determine the foam's long-term stability under field weather conditions were completed. The handling and performance characteristics of the foam necessary for development of this application were determined. Factors that affect the physical properties and the utilization of the foam were quantified. These included the proportions of the foam components, the mixing temperature of the prefoam solution, the application temperature, and the rate of foam generation. The newly developed foam might be ideal for freeze and frost protection in agriculture.
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.
Seenithamby Lgogendra, Harry W. Janes, Harry Motto, and Gene Giacomelli
With the increasing establishment of greenhouses in conjunction with resource recovery projects (i.e., producing electricity by burning a low cost fuel), greenhouse facilities have access to low cost heat and in many cases electricity as well. In this regard we have been studying the production of spinach with the use of supplemental light.
The goal of the research was to establish the relationship between light and productivity and to also investigate the effects of light on tissue nitrate levels. The data indicate that an average daily PPF of 13-14 moles will provide enough energy to maximize the plant's relative growth rate. It was also found that supplemental HPS light with a PPF of 90 μmoles/m2/sec given over a 12h period will increase the total light received by a plant in mid-winter by about 50% and lead to a 10% decrease in leaf nitrate level.
Richard Snyder*, David Ingram, Blake Layton, Ken Hood, Mary Peet, Mary Donnell, Gene Giacomelli, Joe Kemble, Pat Harris, and Frank Killebrew
The Mississippi (MS) Greenhouse Tomato Short Course has been held every March since 1989. The purpose of this 2-day, intensive training is to educate growers so they will be able to successfully grow greenhouse tomatoes as a viable horticultural business. With a mixture of experienced, novice, and prospective growers, it is just as important to provide current growers with research based, practical information, as to expose potential growers to the realities of the business, helping them make an informed decision before investing time and money. Beginning as a small program for a handful growers in the conference room at the Truck Crops Experiment Station, it has gradually grown in number and diversity of participants and invited speakers, depth of subject matter, and geographic origin of growers and speakers. The 2003 program had 142 participants from over 20 states and 4 countries, making it the largest such program in the United States. This is in keeping with the recent trend. The typical lineup of topics includes the basics of producing a commercial crop of hydroponic greenhouse tomatoes, the budget for establishing and operating a greenhouse business, marketing and promotion, pest and disease identification and management, and the grower's point of view. Other topics, varying year to year, include heating, cooling, and ventilation of greenhouses, record keeping, new technologies, biological control, diagnostics, and alternative crops. For 2004, the subject of organic production will be introduced. With targeted extension programming such as this Short Course, the greenhouse tomato industry in MS has grown from 15 growers in 1989 to 135 growers today, producing $6.5 million in annual gross sales. Complete information can be found at www.msstate.edu/dept/cmrec/ghsc.htm.
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.