A SYSTEM FOR MEASUREMENT OF TRANSPIRATION, AIR MOVEMENT AND PHOTOSYNTHESIS IN THE GREENHOUSE

This paper describes various efforts to integrate evapotranspiration measurements carried out by inexpensive lysimeters with the information received by standard sensors to measure radiation, temperature, humidity and CO2 concentrations within a commercial greenhouse (GH). Such a system enables the calculation of air exchange, transpiration and photosynthetic activity of the entire GH canopy.
Integrating the output of these instruments for instantaneous calculations necessitates resolving variations in time responses as well as effects of precision, drifts, temperature and hysteresis.
These problems were solved by the adjustment and development of calibration, positioning and operating methods, setting of synchronization and averaging procedures.
The reliability of the collected data was confirmed by logical distribution profiles of the calculated characteristic values along the day and by their spatial distribution within the GH.
The information flow was slowed by the procedures mentioned above.
However, this measuring system suffices for the validation and calibration of crop models and for use as input for GH controllers.

International Workshop on Models for Plant Growth and Control of Product Quality in Horticultural Production

E. Dayan, E. Presnov, J. Dayan, A. Shavit

Greenhouses, Evapotranspiration, Canopy photosynthesis, Air exchanges

https://doi.org/10.17660/ActaHortic.2004.654.12