It seems that a tomato crop can do with less CO2 than the current CO2 dose levels applied in greenhouses. This is the result of research carried out by Wageningen UR Greenhouse Horticulture together with GreenQ-Improvement Centre in Bleiswijk. This research is carried out in the context of the programme Greenhouse as Energy Source.
Availability of CO2 and the amount to be dosed is a recurring issue in Next Generation Greenhouse Cultivation. When there is no heat demand, CHP (Combined Heat Power) or heater produce no CO2. Use of pure CO2 is the solution in this situation but this costs money and when permanent supply is impossible, CO2 must be delivered via tank transport. A lower availability of CO2 in the future requires a well thought-out strategy for the best possible dosing to achieve optimum plant results.
This is why Wageningen UR Greenhouse Horticulture is in the project Limited CO2 Dosing in Next Generation Tomato Cultivation conducting an experiment in two greenhouse sections. In the first section a normal CO2 dose level of 200 kg/(ha.h) is resulting in an annual use of 65 kg/m2 CO2 . CO2 dosing in the second section is adjusted resulting in half the annual amount (32.5 kg/m2). The adjustments involve the dosing capacity and the moment of dosing is dependent on ambient conditions. The variety Komeett is used in the experiment, the variety also used in this year’s Next Generation Greenhouse Cultivation experiment.
New questions
Cultivation is now coming to a close and the results give a new view on CO2 dosing in relation to climate. Production of the crop in the section with limited amounts of CO2 were only 1.5 kg/m2 lower. During a presentation for growers and suppliers researcher Arie de Gelder recently warned that this is a premature evaluation: “Proper analysis of our observations is required.” The results until now give cause for a debate about the current CO2 dosing methods.