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Soil
Oxygen diffusion meter
In plant cultivation it is very important that the soil has proper ventilation. The necessary oxygen supply for the roots and the discharge of the carbon dioxide gas that is formed there, in case of most cultivated growth, takes place via the soil. Also soil chemical processes depend on the presence of oxygen in the soil.
14.36 Oxygen diffusion meter
The oxygen diffusion meter measures the mobility of oxygen in the soil. A mobility that is important for the availability of oxygen for plants. The method: measuring the electric current required for the reduction of all oxygen present at the surface of a cylindrical Pt-electrode in the soil. The flow of oxygen through the air-filled pores and the water film on the electrode is measured until the steady state is reached. The Oxygen Diffusion Rate (ODR) probe (Pt-electrode) should be placed in undisturbed soil. To this purpose a hole is pre-drilled to a depth of approximately 10 mm above the measuring point, after which the probe is lowered and carefully pushed into the bottom of the auger hole. It is advised to remove the electrode from the soil after a series of measurements in order to clean it. The meter provides a stabilized voltage between the ODR-probe and the Ag-AgCl-reference electrode. In very dry soils only part of the electrode will be covered in water. This results in a rising impedance between soil and electrode. In such a situation the meter can also be used to perform a redox-potential measurement.
14.36 Oxygen diffusion meter
The oxygen diffusion meter measures the mobility of oxygen in the soil. A mobility that is important for the availability of oxygen for plants. The method: measuring the electric current required for the reduction of all oxygen present at the surface of a cylindrical Pt-electrode in the soil. The flow of oxygen through the air-filled pores and the water film on the electrode is measured until the steady state is reached. The Oxygen Diffusion Rate (ODR) probe (Pt-electrode) should be placed in undisturbed soil. To this purpose a hole is pre-drilled to a depth of approximately 10 mm above the measuring point, after which the probe is lowered and carefully pushed into the bottom of the auger hole. It is advised to remove the electrode from the soil after a series of measurements in order to clean it. The meter provides a stabilized voltage between the ODR-probe and the Ag-AgCl-reference electrode. In very dry soils only part of the electrode will be covered in water. This results in a rising impedance between soil and electrode. In such a situation the meter can also be used to perform a redox-potential measurement.
