Prerequisite for the analysis of soil gases and gas exchange between soil, plant and atmosphere is the catchment of these gases in order to be able to convey them to an analyzer. For that purpose different systems are available depending on the planned application.
- Closed hoods / closed measuring chambers:
Closed systems do not allow the exchange of air between the sample chamber and the atmosphere. They enable to observe the accumulation of a gas component over time. By assimilation in the closed measuring chamber, the concentration of gas components with a concentration below the measurement range of the analyzer, can be increased so that these are measurable.
- Open Covers / Open test chambers:
Open systems allow the gas exchange with the atmosphere and provide a measurement path that can be used to determine flow rates according to the gradient. The opening to the atmosphere ensures natural as possible conditions in the measuring chamber and a minimized influence on existing vegetation.
- Lance probes:
Lance probes are inserted into the ground and thus enable the extraction of soil gases from specific depths. Lance probes can be used for continuous sampling in the field as well as for discrete sampling for examination in the laboratory .
Which system is most suitable and which peripheral device should be used, depends on the intended application and the aim of the investigation.