Manual chamber method
The closed chamber method is a widely used technique in quantifying greenhouse gas emissions (GHG). In fact, more than 95% of published emission studies used this method. This approach is low cost and can be implemented in remote sites as it can run without power supply. It can be used to measure emissions at the field and farm level and further applying it in large scale GHG estimations which is an essential component of national emission inventories.
The closed chamber approach works by the accumulation of GHG fluxes in the chamber's headspace. The gas concentration inside the chamber increases over time; this indicates the amount of flux from the soil.
In carrying out the experiment, chambers are placed in specific locations on the agriculture plot and, at certain time intervals, air samples are physically extracted from the chamber using an air-tight syringe. The concentration of GHG samples is quantified using a gas chromatograph and the soil flux of GHGs is calculated through regression of the gas concentration with time.