SIMULATION OF GREENHOUSE CROP PHOTOSYNTHESIS: VALIDATION WITH CUCUMBER, SWEET PEPPER AND TOMATO

A model of greenhouse crop photosynthesis was validated with measurements of net photosynthesis and nighttime respiration of cucumber, sweet pepper and tomato.
Photosynthesis measurements were done during large parts of the growing period, using greenhouse compartments (size 192 m²) as assimilation chambers.

Non-photosynthetic crop respiration was simulated as growth respiration plus maintenance respiration.
Maintenance respiration was calculated based on dry weights of plant organs and growth respiration was calculated from average crop dry weight increase.
Measured crop gross photosynthesis was taken as measured net photosynthesis plus measured average nighttime respiration.
Simulated gross photosynthesis at different CO₂ levels agreed satisfactorily with measured gross photosynthesis for all three species.
Simulated nighttime respiration only agreed with measured respiration at moderate crop dry weights and Leaf Area Indices at 2 – 3, and mostly underestimated respiration.
At very high crop dry weights nighttime respiration was overestimated.

Simulations indicated that the three species had a similar crop photosynthetic response to environmental conditions.

IV International Symposium on CO2 in Protected Cultivation

H. Gijzen, J.G. Vegter, E.M. Nederhoff

https://doi.org/10.17660/ActaHortic.1990.268.6