Physiological modelling shows the options for a grower how to sustain high production levels with constrained supply of CO₂ fertilizer

In the coming years the supply of industrial CO2 for greenhouse crop fertilization will decrease due to the measures to reduce fossil fuel use and the carbon footprint of industry. The limitation in CO2 supply urges growers to dose CO2 as efficient as possible. Using an extensive physiological model of tomato, we simulated the crop’s adaptation to lower CO2 concentrations while aiming at a similar production level as for high CO2 supply. Despite a twofold decrease in CO2 supply the modelled production was shown to hardly decrease as a result of a smart CO2 dosage following crop demand and a constrained room opening without causing too high temperatures. The higher CO2 utilization efficiency was also increased by simulating an increase in CO2 assimilation of the leaves as observed in experiments on plant adaptation to lower CO2 levels. A series of model scenarios were carried out to test the effects of air movement, humidity and timing of additional CO2 supply on CO2 utilization efficiency. The prospects of designing a feasible CO2 constrained greenhouse system are discussed.