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EN
The author determined the ODR (oxygen diffusion rate) and water retention in the range of pH 0-2,8 in some organic and mineral soils of the Valley Odra river , the investigations showed typical relations between ODR and the moisture content of sand and loam soils. At the some time the author ascertained that the method of measurement does not give reliable results with a low moisture content (e.g. in sand soils already at pF 2,5). Soils with a heavier texture show weak oxygen influx (results obtained in the laboratory), while sand solis give results weighted by the error resulting in the laboratory from separating the sample from its natural environment and its evaporation to a given pF. The organic horizons of peat soils are featured by a low ODR measured in field conditions at full water capacity. In the laboratory an increase of ODR is visible in such samples; this is the result of an easier access of oxygen after their isolation from the profile. It is possible to conclude on a small serviceableness of the method (at the present stage) in laboratory conditions owing to possible sources of disturbance of measurements.
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EN
ODR was calculated for the soil water extracts prepared from freshly taken soil, wet soil stored in plastic bags and air dry soil. ODR in KCI solution was used as reference.ODR recorded for the extracts obtained from freshly taken soil was lower than for the extracts prepared from the stored soil samples. This indicates that for ODR measurements fresh soil should be investigated.
EN
Influence of the measuring procedure on the repeatability of measurement of the potential oxygen flux density in the soil has been presented. Five measuring procedures were applied: measurements taken one directly after another, reinstallation of the electrode after each measurement , reinstallation of the electrode after each measurement with a simultaneous mechanical cleaning of surfaces, measurements with 15-min breaks between consecutive measurements, measurements with electrochemical "cleaning" of the electrode surface.The OFD value was determined by a voltamperometric method using a tri-electrode measuring system. It was found out that the best repeatability can be obtained by repeating the measurement with 15-min (or longer) time intervals.
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