EFFECTS OF ENVIRONMENTAL CONDITIONS ON GROWTH AND PRODUCTION OF CUCUMBER; COMPARISON BETWEEN EMPIRICAL AND SIMULATION DATA.

In order to validate a computer simulation model on crop growth, experiments were done with glasshouse cucumber (Cucumis sativus L.). In the experiment reported here, the effect of carbon dioxide (CO₂) was studied.
In twelve compartments of an experimental glasshouse complex, cucumber cv. ‘Lucinde’ was planted januari 7, 1985. Four CO₂-concentrations (200, 330, 600 and 950 ppm) were given during daytime, from the start of the fruit growth period (januari 28) until the end of the experiment.
The other environmental conditions closely resembled the growing conditions in practical greenhouses in the Netherlands.

The growth and production were measured.
The first production was one week earlier in the highest CO₂ treatment than in the lowest. 110 days after planting the yields in the treatments (200, 330, 600, 950 ppm CO₂) were, compared to the production at 330 ppm, respectively: -30, 0, +37 and +45 %. The LAI was about 2 to 2.5 at day 60 and remained about constant because of pruning.

The main climatic factors in the experimental greenhouses (radiation outside the greenhouse, temperature and CO₂ concentration of the greenhouse atmosphere) were continuously measured and recorded.
These data were used as input data for a computer simulation model.
The model calculates the vegetative growth and the fruit production on the basis of simulated photosynthesis rate, respiration rates and dry matter distribution.
Comparisons of the simulated and the measured results showed a satisfactory agreement until about day 60, when pruning of the crop influenced the LAI in the experiment.
When the simulated LAI was corrected for the pruning, the simulation of the production after day 60 improved.

Symposium Greenhouse Climate and its Control

E.M. Nederhoff, A.H.C.M. Schapendonk

https://doi.org/10.17660/ActaHortic.1985.174.31