THE CO2 REQUIREMENTS OF GREENHOUSE CROPS
Greenhouses do not constitute closed systems so that a large portion of the CO2 released by the soil is lost. On the other hand, there is no good correspondence between soil respiration and the course of CO2 requirement.
The indication that a tomato crop needs 6–7 g CO2.m2.h-1 can hardly be of further use. Unfortunately, in the literature are lacking data concerning the net values of assimilation activity of greenhouse crops by hours, excepting the curve for the day course of CO2 uptake by tomato crops presented by the author (Daunicht, 1968).