The most recent literature on CO2 use by plants was examined. Already much is known on photosynthesis and CO2 assimilation. Genetic modification was shown to boost photosynthesis by 20%. Naturally, the plant adapts to CO2 concentration. Also in sweet pepper and tomato crops adaptation to lower CO2 levels were observed, yet the extend and the rate of adaptation is hard to predict. The gathered knowledge was used to simulate crop growth at various supply strategies of CO2. The goal was to reduce CO2 dosing while maintaining an economically viable tomato yield. Simulations showed that under normal light conditions the crop can maximally assimilate 15 kg CO2 m-2, while conventional CO2 dosage is more than triple resulting in much loss to the air. Continuous applications of 50 kg CO2 ha-1 hr-1 led to a yield reduction of 20% relative to 200 kg CO2. Further model wise optimization of the CO2 dosing resulted in much lower CO2 losses while reducing fruit yield with only 2%. In this scenario only 13 kg CO2 m-2 j-1 was supplied, at 450 ppm during roof opening of >10%. A further optimization was enabled by allowing a 2° higher ventilation temperature. The results give options for a much lower CO2 dosage in practice than currently used.
|Name||Rapport / Stichting Wageningen Research, Wageningen Plant Research, Business unit Glastuinbouw|