ISHS Acta Horticulturae 440: International Symposium on Plant Production in Closed Ecosystems
AN ANALYSIS OF CROP GROWTH UNDER PLASTIC FILMS WITH DIFFERENT LONG-WAVE RADIATION TRANSMITTANCE |
| Authors: | T. Hamasaki, M. Okada |
| Keywords: | crop growth, greenhouse environment, leaf temperature, long-wave radiation, plastic film, soil temperature |
| Abstract:
Two wind tunnels (called "temperature gradient chamber ; TGC"), one covered with polyethylene (PE) film (long-wave radiation (LR) transmittance = 0.85) and the other with polyvinyl chloride (PVC) film (LR transmittance = 0.33), were used to evaluate the effects of LR transmittance of covering films on the relationships between air, soil and leaf temperature of spinach, and between air and soil temperatures and growth of rice. For both TGCs, the plots for mean soil temperature and mean leaf temperature against mean air temperature showed a linear relationship. Under PVC the soil to air temperature relationship was approximately 2 °C higher than under PE. Also, for spinach, the leaf to air temperature relationship under PVC was higher than under PE. In spite of the difference in the LR transmittance of covering films, the leaf to soil temperature relation showed one connected linear line under PVC and PE. Growth of rice seedlings had a stronger relation to soil temperature than to air temperature, indicating that soil temperature may need to be considered in analysis or control of crop growth. | |
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