ISHS Acta Horticulturae 718: III International Symposium on Models for Plant Growth, Environmental Control and Farm Management in Protected Cultivation (HortiModel 2006)
MICROCLIMATE AND TRANSPIRATION OF GREENHOUSE ROSE CROPS: MEASUREMENTS AND SIMULATION |
| Authors: | O. Liran, J. Tanny, M. Teitel, M. Barak |
| Keywords: | roses, temperature, Penman-Monteith equation |
| Abstract:
Prediction of greenhouse microclimate and crop temperature and transpiration from external conditions, using relatively simple models, is still considered a challenge. The goal of this research is to compare experimental results obtained in a greenhouse in which roses were grown with an existing theoretical model. Experiments were done in a naturally ventilated greenhouse with a floor area of 69 mē that can be ventilated by two side openings, each about 3.0 mē, one on the west wall and the other on the east wall. A roof opening with an area of about 5 mē was also available. Two modes of natural ventilation were studied, side openings, and a combination of roof and side openings. The side openings were covered with a 50-mesh screen while the roof opening was covered with a 17-mesh one. The potted plants (245 roses) were arranged in six rows in the east-west direction. Temperature and humidity were measured at the two ends of the central row at a height of about 1.5 m and at four heights (0.15, 1.1, 2 and 3 m above floor level) at the center of the greenhouse. Transpiration was measured by five lysimeters, four measuring the transpiration of one plant each and one measuring the transpiration of other four plants. Net radiation, solar radiation and PAR were measured at the center of the greenhouse about 0.5 m above the plants top. Soil heat flux was measured about 5 cm below soil surface. A theoretical model (Boulard and Wang, 2000) based on Penman-Monteith equation was used to predict the interior air and crop temperatures and the transpiration rate. A good agreement was obtained with regard to the air temperature and transpiration between the model and experiment results. Averages of measured and predicted values were calculated for nine days of measurements, four hours each day (10:00 14:00). The average measured and predicted air temperatures were 30.5 and 30.7°C respectively and the corresponding values of the transpiration were 279 and 273 W m-2. | |
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