Some 30 growers attended the recent Arena Session at GreenQ Improvement Centre. Subject at hand: diffuse light and the monitoring of photosynthesis, a topic on many people’s mind these days. Sander Pot of Plant Dynamics gave a clarification on the relationship between photosynthesis and light in relation to the time of day and climatic factors such as moisture, temperature and CO2. At low light levels, the rule '1% more light gives 1% more photosynthesis' does indeed apply. With higher light levels, there are often limiting factors, causing extra light not to lead to more photosynthesis. Pot stressed that it is of importance to know which photosynthetic system the plant has: C3, C4, or CAM. A limiting factor that often occurs is that the stomata are not sufficiently open to be able to take in enough CO2.
Filip van Noort has spent the past two years doing research in the framework of the project 'Grip on Light'. This research was funded by Greenhouse as Energy. The tests showed that, at higher RH, plants can tolerate more light, and thus a growing acceleration of more than 25% is possible with pot anthurium. Van Noort pointed out, however, that the plant structure may change if there is more light in the greenhouse. It is advisable to then adjust the plant density.
After these two introductions a visit was paid to the Daylight greenhouse at IDC Energy with Wageningen UR Greenhouse Horticulture. In this innovative greenhouse, sunlight is deflected through Fresnel lenses on the south side of the nursery. This allows the direct sunlight to be converted into heat and / or electricity.
The afternoon was organized in the framework of ‘Collaborating on Skills’. This is a joint initiative of GreenQ Improvement Centre, Wageningen UR Greenhouse Horticulture, Priva, Certhon and TNO with the aim of promoting new, sustainable technologies in horticulture. For five years, the project will be co-financed by the Ministry of Economic Affairs and the Province of South Holland.