Agriculture Reference
In-Depth Information
• Connect the other piece of tubing on the opposite end of
the Draeger tube, and attach one of the needles to the far end
of the tubing.
• After 30 minutes, insert the needle in the measurement
apparatus through one of the stoppers into the head space
inside the pipe, and insert the other needle (which is attached
to nothing) through the other stopper to provide for airflow.
Draw air through the Draeger tube by pulling back slowly on
the plunger at the rate of 5 cc per second until 100 cc of air
has been drawn into the syringe.
• Read the color change on the Draeger tube. If the color
change has not reached the 0.5 mark in the column labeled “n
= 1", take 4 additional samples. Expel the air from the syringe
before each sample by first disconnecting it from the tubing
and then reconnecting it to the tubing before the next draw.
Do all 5 draws at the rate of 5 cc per second until 100 cc of air
has been drawn into the syringe. Read the results from the “n
= 5" column on the Draeger tube.
You can calculate the amount of CO2 (and hence the soil
respiration and its biological activity) through use of the
following formula:
