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P.E. Danforth, T.M. Waliczek, S.M. Macey, and J.M. Zajicek

communities 14 Aug. 2007 < > National Wildlife Federation ® 2007 Schoolyard Habitats® 23 June 2007 < > Pale, P.E. Thompson, K.F. Keyes, M. 2001 Students, standards, and

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P.E. Cappiello

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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.

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Margarita Velandia, Karen L. DeLong, Annette Wszelaki, Susan Schexnayder, Christopher Clark, and Kimberly Jensen

billion pounds of plastic are used every year in the production of crops ( Fessenden, 2015 ). It is estimated that in vegetable production alone, U.S. farmers are using about 143,300 tons of PE mulch per year ( Shogren and Hochmuth, 2004 ). Recycling

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Christos Lykas, Constantinos Kittas, Nikolaos Katsoulas, and Maria Papafotiou

Heins, 2002 ). One of the limitations of photoselective (P) polyethylene (PE) films is that they reduce photosynthetic photon flux density ( PPFD ) affecting the photosynthetic rate of the plants ( Wilson and Rajapakse, 2001 ). Furthermore, light

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Huan Zhang, Carol Miles, Shuresh Ghimire, Chris Benedict, Inga Zasada, Hang Liu, and Lisa DeVetter

summer planting systems are promising, weed management is still a challenge. Plastic mulches, such as PE, have been used globally in agriculture since the 1960s, primarily in annual production systems, and provide the benefits of weed control, improved

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Ronald W. Moore, P.E. Read, and T.P. Riordan

Stolon nodal segments of Buchloe dactyloides (Nutt.) Engelm. were removed from greenhouse grown plants and placed on Gamborg's B5 medium in order to determine nodal position and 2,4-D level required to give maximum callus initiation. 2,4-D levels used were 5uM, 16uM, 35uM, and 50uM. Six nodal segments were grouped according to position on the stolon, from the most recent node (node one) to the basal node (node 6). It was concluded that node 4 gave statistically greater callus mass than nodes 1, 2, 3, 5, and 6. Increasing levels of 2,4-D suppressed callus initiation, with maximum response occurring at 5uM 2,4-D.

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W.L. Berndt, P.E. Rieke, and J.M. Vargas Jr.

Three bio-organic materials were evaluated at four application rates, based on N contents, for their potential to degrade Kentucky bluegrass (Poa pratensis L.) thatch in a field experiment. Treated thatch was reduced in thickness and had increased earthworm (Lumbricus spp. Hoff.) populations when compared to untreated thatch. Thatch thickness was negatively correlated with level of N (r = –0.91), thatch lignin content (r = –0.94), and earthworm population in the thatch (r = –0.64), and positively correlated with thatch cellulose content (r = 0.62).

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Lisa W. DeVetter, Huan Zhang, Shuresh Ghimire, Sean Watkinson, and Carol A. Miles

exploring plasticulture production using day-neutral cultivars targeting the fresh market. Black PE mulch is extensively used in plasticulture because of its low cost and ability to manage weeds, conserve soil moisture, modify soil temperatures, increase