ISHS Acta Horticulturae 797: International Workshop on Greenhouse Environmental Control and Crop Production in Semi-Arid Regions
PHOTOSELECTIVE SHADE NETTING INTEGRATED WITH GREENHOUSE TECHNOLOGIES FOR IMPROVED PERFORMANCE OF VEGETABLE AND ORNAMENTAL CROPS |
| Authors: | Y. Shahak, E. Gal, Y. Offir, D. Ben-Yakir |
| Keywords: | colored shade-nets, light scattering, crop yield, pest control, protected cultivation |
| DOI: | 10.17660/ActaHortic.2008.797.8 |
| Abstract:
Photoselective shade-netting is an emerging approach in protected cultivation. The photoselective net products are based on the introduction of various chromatic additives, light dispersive and reflective elements into the netting materials. They are designed to selectively screen various spectral components of solar radiation (UV, PAR and beyond), and/or transform direct light into scattered light. The spectral manipulation is aimed to specifically promote desired physiological responses, while the scattering improves the penetration of the modified light into the inner plant canopy. Additional potential benefits relate to photoselective effects on plant pests, beneficial insects or diseases. Studies of ornamental crops, traditionally grown in shade-net houses, revealed distinct responses to the red, yellow, blue, grey and pearl nets, compared with common black nets of the same shading factor. These include stimulated vegetative vigor, dwarfing, branching, leaf variegation and timing of flowering. The photoselective netting concept was further tested in vegetable cultivation in either net-houses, or in combination with insect-proof nets or greenhouse plastic film covers. The red and pearl nets repeatedly increased the productivity of leafy crops, bell peppers and ornamentals, compared with each crop’s standard cover. Although the shade-net holes allow free passage of small pests, the rates of pest infestations and vector-borne viral diseases were affected by the color and reflectivity of the nets. For example, the incidence of an aphid borne cucumber mosaic virus disease was significantly lower under the pearl (10 folds) and yellow (3 folds) nets, compared to black nets. Whiteflies penetration and establishment was 2 fold lower under the Yellow net compared to the black net. The photoselective, light-dispersive shade nets provide a unique tool that can be further implemented within protected cultivation practices. | |
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