Automatic sampling device and method for determining greenhouse gas emission flux from farmland

An automatic sampling device for determining greenhouse gas emission flux from farmland, comprising a static chamber, a flow meter, and a collection box;

• wherein
• the static chamber communicates with a gas inlet of the collection box;
• the flow meter is arranged in a gas pipe between the static chamber and the collection box;
• the static chamber is used to cover plants to be tested and to keep the plants to be tested in a closed environment;
• the flow meter is used to determine a gas flow rate in the gas pipe between the static chamber and the collection box in real time;
• and
• the collection box is internally provided with a plurality of collection loops and a controller, each collection loop is used to collect a gas in the static chamber at different time according to collection settings of the controller;
• and the collection settings comprise:
• gas collection start time, gas collection time interval, and the number of collections,
• wherein the collection loop comprises a gas inlet pipeline, a collection gas bag, and a gas outlet pipeline;
• wherein
• the gas inlet pipeline is used to open a gas path according to a control of the controller for gas collection, and to close the gas path according to a control of the controller after the gas collection is completed;
• the collection gas bag is used for gas collection and is closed after the gas collection is completed;
• and
• the gas outlet pipeline is used to open the gas path for gas exhausting according to a control of the controller after the collection of the collection gas bag is completed, and to close the gas path according to a control of the controller after the gas exhausting is completed;
• and
• wherein the collection box further comprises a gas intake pump and a gas extraction pump;
• wherein
• a gas inlet of the gas intake pump communicated with the gas inlet of the collection box, and a gas outlet of the gas intake pump communicates with a gas inlet of a gas inlet path;
• the gas intake pump is used to collect the gas in the static chamber into a corresponding collection loop;
• a gas inlet of the gas extraction pump communicates with a gas outlet of the gas outlet pipeline, and a gas outlet of the gas extraction pump communicates with a gas outlet of the collection box;
• and
• the gas extraction pump is used to exhaust gases from the gas inlet pipeline and the gas outlet pipeline in the collection loop.