ISHS Acta Horticulturae 162: Symposium on CO2 Enrichment
PREVAILING CO2 CONCENTRATIONS IN GLASSHOUSES |
| Authors: | G. Heij, P.J.A.L. de Lint |
| Abstract:
On days with spring lightintensities, CO2 concentrations in glasshouses with a full-grown crop drops considerably below the ambient concentration of 340 ppm. In order to know which CO2 concentrations are prevailing under Dutch circumstances in the course of a year a recording of the CO2 concentrations was performed. On twenty-four holdings with a variety of types of glasshouses and crops the CO2 concentration, the opening of the ventilators and the position of the CO2 valve were recorded continuously during a period of eigtheen months. For five crops a sample out of this registration, over the three weeks in March, is given. Further, the situation during the five spring months in a crop of aubergine was worked out and presented. Finally, the data of a whole year regarding a house with both a sweet pepper crop and with yearround chrysanthemums are presented with respect to the amount of CO2 deficient hours. In summer, during many hours there is a shortage of CO2 in the glasshouses. From winter till midsummer the number of hours with reduced CO2 concentrations increases from 0 till 11 hours per day. Over the whole season it is seen from the registration on a sweet pepper holding, that from the ca. 4500 dayhours, at least during 1500 hours CO2 concentrations were below 340 ppm. For yearround chrysanthemum about 10 % deficient hours are registered. | |
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