This system consists of a short soil probe and an oxygen content meter. The probe is pushed into the soil manually.  Once at the right depth the probe is lifted slightly.  In this way the probe opens itself. Next, the oxygen content meter is connected to the probe and, using a bellows, soil gas is drawn through the meter and the O2 content is measured, and with that an important growing parameter for trees and plants, can be read. The probe has a small dead volume, so that a measurement can be executed accurately within minutes. The oxygen content meter operates with an electrochemical cell. This cell has a limited service life (about 1.5 years), but can be calibrated easily with air (21%) and with a gas free of oxygen (natural gas, nitrogen).